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This article refers to the chemical recovery of cellulose from fabrics composed of Cotton (CO)/Polyester (PES) achieved using Ionic Liquids (ILs). Initially, the effect of ionic liquids on the surface of the textile is analyzed, determining the influencing factors related to the entry of IL inside the textile and the chemical mechanism that controls the system. This work considers the influence of the time, ratio, and temperature variables on the system, with the aim of defining which of them has a greater influence on the process. The ability of ionic liquids, specifically 1-Allyl-3-Methylimidazolium Chloride (AmimCl), to dissolve cellulose and subsequently regenerate the material through a simulation of the wet spinning process is evaluated. The responsible for the fiber’s inflation, water or DMSO, has also been another factor of study, analyzing the influence of each solvent and the interactions when in contact with the ionic liquid. Finally, the regenerated substance is characterized by its surface structure using the Scanning Electron Microscope (SEM), its molecular structure by Infrared Spectroscopy Analysis (FTIR), and its thermal stability by Thermogravimetric Analysis (TGA) Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura

Biodegradation of polyesters driven by enzymes is considered as one of the most effective way of degradation of these materials, as a way to control plastics accumulation in the environment. In this study, we present two different strategies to tune the enzymatic degradation of PBS films triggered by a lipase from Pseudomonas cepacia. Firstly, the kinetics of enzymatic degradation of PBS films was regulated by applying multilayer coats of polysaccharide alginate and chitosan (Alg/Chi) films. Secondly, self-degradable PBS films were prepared by embedding lipase-filled alginate particles. For comparison purposes, a detailed enzymatic degradation study of neat PBS films exposed to a lipase from P. cepacia in solution was made to determine the main experimental parameters influencing their degradation in solution. The results showed that an increase in enzyme concentration increased the degradation extent and rate of neat PBS films. At a fixed enzyme concentration, stirring of the solution containing the enzyme and the PBS also increased the biodegradation rate. In the case of the PBS films coated with a different number of Alg/Chi layers by spray-assisted LbL and subjected to enzymatic degradation experiments in solution, the extent of degradation was found to be dependent on the number of protective coating layers. Therefore, the Alg/Chi biobased coating constitutes an effective barrier to the diffusion of the lipase, thus proving its effectiveness in modulating the enzymatic activity as a function of coating thickness. In the case of self-degradable PBS containing lipase-embedded alginate beads (employed to protect the enzyme during high-temperature processing), only limited biodegradation was observed as the amount of encapsulated enzyme employed was too small. Nonetheless, these results are promising, as the enzymatic activity –indicative of the degradation capacity of the enzyme– determined for all these samples was about 2 orders of magnitude lower than that of previous assays., This research was funded by the projects MAT2017-83014-C2-1-P, MAT2017-83014-C2-2-P, PID2020-113045GB-C21 and PID2020-113045GB-C22 funded by MCIN/ AEI /10.13039/501100011033 and by the Basque Government through grant IT1503-22. We would also like to acknowledge the financial support from the BIODEST project; this project has received funding from the European Union’s Horizon 2020 Research and Innovation Programme under the Marie Skłodowska-Curie grant agreement No. 778092. M.I.P. is supported with an FPI contract (PRE2018-086104) to develop a PhD thesis. R.H. is member of the CSIC Interdisciplinary Thematic Platform (PTI+) Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy+ (PTI-SusPlast+). J.M.R. is a FRS-FNRS Senior Research Associate. Authors would also like to thank Dr. Ana Beloqui for helpful discussions on enzymatic activity.

El consum de tèxtil per habitant creix de manera exponencial, de manera que, el desenvolupament de nous processos sobre la gestió i els tractaments de residus tèxtils resulta una oportunitat clau per aconseguir models integrals d’economia circular que assegurin el tancament dels cicles. Actualment, es calcula que aproximadament un 80% dels residus tèxtils generats estan constituïts per fibres de cotó (CO) i polièster (PES). L’heterogeneïtat en els residus tèxtils és tot un repte per a la indústria tèxtil, per la qual cosa en aquest projecte s’estudia la recuperació de la cel·lulosa provinent de teixits PES/CO a partir de l’ús de líquids iònics (ILs). Inicialment s’analitza l’efecte dels líquids iònics sobre la superfície del teixit, determinant els factors influents referents a l’entrada del IL a l’interior del teixit i el mecanisme químic que governa el sistema. En aquest projecte es contempla l’estudi de les variables de temps, ràtio i temperatura del sistema, amb l’objectiu de definir quina d’elles té una major influència sobre el procés. S’avalua la capacitat dels líquids iònics, en concret de l’AmimCl, per a dissoldre la cel·lulosa i posteriorment regenerar la matèria mitjançant una simulació del procés wet spinning. El medi d’inflament de la fibra, aigua o DMSO, també ha estat un altre factor estudiat, examinant així la influència de cada dissolvent i les interaccions quan entren en contacte amb el líquid iònic. Finalment, de la matèria regenerada es caracteritza la seva estructura superficial a partir del microscopi electrònic d’escombratge (SEM), la seva estructura molecular mitjançant un anàlisis d’espectroscòpia infraroja (FTIR) i la seva estabilitat tèrmica amb un anàlisi termogravimètric (TGA). El consumo de textil por habitante crece de manera exponencial, de manera que, el desarrollo de nuevos procesos sobre la gestión y los tratamientos de residuos textiles resulta una oportunidad clave para conseguir modelos integrales de economía circular que aseguren el cierre de ciclos. Actualmente, se calcula que aproximadamente un 80% de los residuos textiles generados están constituidos por fibras de algodón (CO) y poliéster (PES). La heterogeneidad en los residuos textiles es todo un reto para la industria textil, por lo que en este proyecto se estudia la recuperación de la celulosa proveniente de tejidos PES/CO a partir del uso de líquidos iónicos (ILs). Inicialmente se analiza el efecto de los líquidos iónicos sobre la superficie del tejido, determinando los factores influyentes referentes a la entrada del IL en el interior del tejido y el mecanismo químico que gobierna el sistema. En este proyecto se contempla el estudio de las variables de tiempo, ratio y temperatura del sistema, con el objetivo de definir cuál de ellas tiene una mayor influencia sobre el proceso. Se evalúa la capacidad de los líquidos iónicos, en concreto del AmimCl, para disolver la celulosa y posteriormente regenerar la materia mediante una simulación del proceso wet spinning. El medio de inflamiento de la fibra, agua o DMSO, también ha sido otro factor estudiado, examinando así la influencia de cada disolvente y las interacciones cuando entran en contacto con el líquido iónico. Finalmente, de la materia regenerada se caracteriza su estructura superficial a partir del microscopio electrónico de barrido (SEM), su estructura molecular mediante un analisis de espectroscopia infrarroja (FTIR) y su estabilidad térmica con un analisis termogravimétrico (TGA). Textile consumption per inhabitant is growing exponentially, and therefore the development of new processes related to the management and treatment of textile waste is a key opportunity to achieve comprehensive circular economy models that ensure the closure of cycles. Nowadays, it has been estimated that approximately an 80% of the textile waste generated is composed of cotton (CO) and polyester (PES) fibers. The heterogeneity in the textile waste is a huge challenge for the textile industry, and for this reason this project studies the recovery of cellulose coming from textile fabrics composed of PES/CO making use of ionic liquids (ILs). Initially, the effect of ionic liquids on the surface of the textile is analyzed, determining the influencing factors related to the entry of IL inside the textile and the chemical mechanism that controls the system. This project considers the study of the time, ratio, and temperature variables of the system, with the aim of defining which of them has a greater influence on the process. The ability of ionic liquids, specifically AmimCl, to dissolve cellulose and subsequently regenerate the material through a simulation of the wet spinning process is evaluated. The responsible for the fiber’s inflation, water or DMSO, has also been another factor of study, analyzing the influence of each solvent and the interactions when in contact with the ionic liquid. Finally, the regenerated substance is characterized by: its surface structure using the scanning electron microscope (SEM), its molecular structure by infrared spectroscopy analysis (FTIR) and its thermal stability by thermogravimetric analysis (TGA).

[eng] Rapid population growth is leading to many environmental problems, among which a large waste generation should be highlighted. More than 40% of these wastes correspond to organic wastes that are mainly treated by composting, anaerobic digestion, incineration, or even landfilled. Hence, it is important to implement new treatment strategies within the circular economy concept transforming organic waste treatment plants into biorefineries. In this way, acidogenic fermentation emerges as a key technology to valorise these substrates producing high value- added products such as volatile fatty acids (VFAs), that could be further transformed into bioplastics (i.e., polyhydroxyalkanoates or PHA). Consequently, acidogenic fermentation and co-fermentation of waste activated sludge (WAS) and food waste (FW) were studied to achieve a VFA-rich effluent for its subsequent conversion into PHA. The pH effect on the acidogenic fermentation of FW was studied in batch mode (pH range from 4 to 11) and in semi-continuous fermenters working under acidic (6) and alkaline pH (9.5-10). Batch tests revealed that pH between 6-9 could lead to a higher VFA production, with a higher acetic acid content when pH increased within this range. In the semi-continuous fermenters, a maximum VFAs yield of 503.1 mgCOD/gVS was obtained when working at pH 6 with acetic, butyric and caproic acids as majoritarian VFAs, while at pH 10, a lower yield (315.1 mgCOD/gVS) was obtained with acetic as the main acid. WAS and FW co-fermentation was explored (50%, 70% and 90% WAS on VS basis), demonstrating the benefits, since a higher fermentation yield was obtained in WAS/FW co-fermentation assays compared to WAS or FW mono-fermentation. In all mixtures tested, the buffer capacity of WAS was enough to maintain the pH above inhibitory levels without reagents addition. Moreover, when the proportion of FW in the WAS/FW was raised, more butyric and less propionic acid was produced achieving a maximum fermentation yield of 480 mgCOD/gVS when the mixture was 50%FW+50%WAS. Since the effect of each FW fraction has been barely studied, discontinuous assays using diverse FW fractions were also performed. The principal components analysis (PCA) revealed the relation between each fraction and each fermentation profile. Furthermore, these assays were essential to understanding the importance of balancing the protein-to-carbon ratio to achieve a maximum VFA yield of about 500 mgCOD/gVS. WAS and FW co-fermentation was studied under long-term conditions in semi-continuous fermenters at several organic loading rates (OLR). This study demonstrated the importance of microorganisms’ immigration with the feed substrates and their adaptation in semi-continuous processes. The stages carried out at OLR 9 and 11 gVS/(L·d) obtained lower VFAs yields probably due to the methanogenic activity favoured at the neutral pH. However, when higher OLR were applied (14 and 18 gVS/(L·d)), the pH started to decrease with a concomitant increase on the VFA yield until achieving a maximum of 475 mgCOD/gVS, with butyric as the main acid. Moreover, this study demonstrates that not only the FW properties and its proportion affect the obtained VFA yield and distribution on co-fermentation, but also the WAS characteristics are important, especially when the pH is low, and the buffering capacity could avoid a sudden drop in the pH. Finally, the start-up and operation of a sequencing batch reactor (SBR) to select PHA-storing microorganisms was performed using a VFA-rich feeding with an OLR of 2.0 and 2.8 gCOD/(L·d). The biomass selection was carried out with a double growth limitation strategy (feast/famine and uncoupled carbon and nitrogen feeding). The successful selection of PHA-storing biomass was confirmed in batch accumulations assays where VFA pulse feeding strategy was used obtaining a PHA content between 44 and 46% (on SS basis) with polyhydroxybutyrate (PHB) as the main component., [spa] El gran crecimiento poblacional está comportando una gran generación de residuos que necesitan ser tratados de la mejor manera posible. Por ello, la Unión Europea propone implementar nuevas estrategias de tratamiento de residuos dentro del concepto de economía circular mediante la transformación de las plantas de residuos en biorrefinerías, donde los residuos son concebidos como productos. En este sentido, el proceso de fermentación acidogénica emerge como una tecnología clave para valorizar los sustratos orgánicos en forma de productos de alto valor añadido como son los ácidos grasos volátiles (AGVs) que pueden ser usados para la producción de bioplásticos (polihidroxialcanoatos o PHA). Los residuos alimentarios y los fangos activos de las depuradoras son los residuos orgánicos más generados en las zonas urbanas. Actualmente son tratados por separado, pero debería contemplarse su tratamiento conjunto ya que resultaría beneficioso debido a las sinergias que se formarían. Por este motivo, la presente tesis se basa en el estudio de la fermentación acidogénica de estos residuos por separado, así como su tratamiento conjunto (co-fermentación) con el fin de generar un efluente rico de AGVs para su posterior conversión en PHA. Para ello, se llevaron a cabo estudios en discontinuo y en semi-continuo para comprobar el efecto del pH en la fermentación de los residuos alimentarios viendo que tiene un papel crucial. Seguidamente, se estudió la co-fermentación de fangos activados con los residuos alimentarios en diferentes proporciones. Este estudio demostró que la capacidad tampón del fango era suficiente para sostener el pH por encima de los niveles inhibitorios. Asimismo, se mostraron sinergias al co-fermentar estos residuos con producciones mayores que mono-fermentando, viendo que la proporción de cada residuo afectaba a la producción y perfil de los AGVs. Además, también se estudió la relación entre cada fracción de los residuos alimentarios y el perfil de producción de ácidos. También se comparó el efecto de trabajar en discontinuo y semi-continuo viendo que tenía importantes efectos debido a la inmigración y adaptación de los microorganismos. Finalmente, se estudió la viabilidad de producir PHA usando un efluente sintético rico en AGVs obteniendo unos buenos porcentajes de acumulación del biopolímero.

This work explores for the first time the enzymatic synthesis of poly(butylene-co-e-caprolactone) (PBSCL) copolyesters in bulk using commercially available monomers (dimethyl succinate (DMS), 1,4-butanediol (BD), and e-caprolactone (CL)). A preliminary kinetic study was carried out which demonstrated the higher reactivity of DMS over CL in the condensation/ring opening polymerization reaction, catalyzed by Candida antarctica lipase B. PBSCL copolyesters were obtained with high molecular weights and a random microstructure, as determined by 13C NMR. They were thermally stable up to 300 °C, with thermal stability increasing with the content of CL in the copolyester. All of them were semicrystalline, with melting temperatures and enthalpies decreasing up to the eutectic point observed at intermediate compositions, and glass transition temperatures decreasing with the content of CL in the copolyester. The use of CALB provided copolyesters free from toxic metallic catalyst, which is very useful if the polymer is intended to be used for biomedical applications. Peer Reviewed Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles

Diblock copolymers (PPDLx-b-pPAAy) were prepared from ω-pentadecalactone and l -glutamic acid or l -lysine amino acids by ring opening polymerization initiated by amino groups. Telechelic amino-ended poly(ω-pentadecalactone) with a length of 15–20 repeating units was firstly synthesized by enzymatic polymerization by means of CALB and then used as macroinitiator for the polymerization of the N-carboxyanhydrides of the two α-amino acids conveniently protected as benzyl and eN-carbobenzoxy derivatives, respectively. The molecular weight of the polypeptide block was accurately controlled by adjusting the amino acid/macroinitiator ratio used in the feed. Copolymers with Mn ranging between ∼5000 and ∼40,000 g·mol−1 and varying ester/peptide ratio were obtained and characterized in detail by GPC and NMR spectroscopy. The thermal properties of these copolymers were evaluated by TGA and DSC, and their structure in the solid-state including their response to heating, were examined by FTIR and XRD at variable temperature. It was shown that the polypentadecalactone segment was crystallized for all compositions and that the polypeptide counterpart adopted a two-dimensional hexagonal packing of α-helices at temperatures above melting of the polyester block. SAXS revealed the presence of a biphasic nanostructure with a repeating distance of 27 nm for the case of glutamic-based copolymers. It was demonstrated that both glutamic and lysine-based PPDLx-b-pPAAy copolymers could self-assemble in well-shaped nanospheres with a diameter in the ∼200–400 nm range and a negative zeta-potential.

Robust and flexible free-standing films made of spin-coated poly(lactic acid) (PLA) and poly(3,4-ethylenedioxythiophene) (PEDOT) nanolayers have been prepared. A steel sheet coated with a sacrificial layer of PEDOT:poly(styrenesulfonate) (PSS) and a spin-coated nanolayer of PLA was used as working electrode for the anodic polymerization of 3,4-ethylenedioxythiophene monomer. The latter was only successfully accomplished when rounded-shape nanoperforations of average diameter 49¿±¿14¿nm were introduced into PLA layers, which was achieved by combining the phase segregation processes undergone by immiscible PLA:poly(vinyl alcohol) (PVA) mixtures with selective solvent etching to remove PVA domains. Nanoperforations allowed the utilization of the semiconducting PEDOT:PSS sacrificial layer to immobilize the electropolymerized PEDOT chains. Morphological and topographical studies show the templating effect of PEDOT layers. In addition of flexibility and mechanical strength, free-standing 5-layered films present good electrochemical activity, evidencing their potential ability to reversibly exchange ions with the medium. These properties offer important advantages with respect to those of neat PLA and supported PEDOT films, as has been illustrated by cell culture and protein adsorption assays. Cell cultures evidenced the superior behavior of 5-layered films as bioactive platforms for fibroblast and epithelial cells proliferation, while adsorption assays reflected their potential as selective bioadhesive surfaces for protein separation

Monomers obtained from renewable feedstocks have emerged as a sustainable alternative to petroleum derived polymers. One of the biomass derived polyesters that has recently been gaining attention as an alternative to petrochemical polyethylene terephtalate (PET) for food and beverage packaging applications is poly(ethylene furanoate) (PEF). However, similar to PET, PEF is not biodegradable or compostable and its end-of-life options must be thus considered to avoid contributing to the accumulation of plastic waste. In this manuscript, PEF films were first produced using thermo-compression, an industrially relevant processing method, and their thermal, mechanical, and barrier properties were determined and compared to those of PET and other biopolyesters to ascertain their suitability for food packaging. Thereafter, the chemical glycolysis of PEF film waste was investigated using a sustainable and thermally stable acid–base organocatalyst. After succesfully deconstructing PEF into bis(2-hydroxyethyl)-furan-2,5-dicarboxylate (BHEF), the obtained BHEF diester was used to resynthesize PEF using the same catalyst to generate a new biopolyester with similar thermal properties to the virgin one in a closed-loop cycle., The authors thank for technical and human support provided by IZO-SGI SGIker of UPV/EHU and European funding (ERDF and ESF). Authors gratefully acknowledge financial support from Spanish Ministry of Science and Innovation (MICI) through projects MAT2017-83373-R and RTI 2018-097249-B-C21.

363 p. In this thesis, the preparation of PBS-ran-PCL biodegradable and biocompatible copolyesters by ring opening-melt polycondensation polymerization with three different molecular weight is presented. The copolymers have been characterized by proton and carbon nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), polarized light optical microscopy (PLOM), scanning electron microscopy (SEM), Raman, FT-IR, GIWAXS and wide angle X-ray scattering (WAXS). The PBS-ran-PCL copolyesters were able to crystallize in the entire composition range and displayed a pseudo-eutectic region. Most copolymers away from the pseudo-eutectic region exhibited a single crystalline phase (PBS-rich or PCL-rich crystalline phase), while within the pseudo-eutectic region the copolymers were double crystalline. Obtained results demonstrated that the copolymers are isodimorphic. Isothermal crystallization kinetics showed that both nucleation density and spherulitic growth rate of the copolyesters are determined by the component that constitutes the majority phase and was a strong function of composition and supercooling. For the infiltrated random copolyesters, results revealed that the nucleation process changed from heterogeneous in bulk to surface or homogeneous nucleation in the nanopores. Polymat

Un dels teixits actuals més utilitzats en la indústria tèxtil és el polièster (PET), tant per les seves propietats físiques i químiques, com pel seu cost assequible per a tothom. No obstant, és un material hidròfob, per tant, no transporta ni dispersa l’aigua líquida alliberada del cos. L’eliminació de calor i aigua del cos permet millorar el nivell de confort. Per tant, si la transpiració queda atrapada arran o a prop de la pell, pot provocar un augment de la temperatura corporal, causant deshidratació, fatiga i disminució del rendiment.[1] És per això que actualment s’estan realitzant experiments per tal de millorar aquesta propietat del PET mitjançant la modificació superficial del teixit. En aquest projecte es pretén augmentar el benestar i el confort del PET augmentant la seva hidrofilitat amb la modificació de la superfície del mateix. Per això, s’han aplicat tres tractaments diferents a mostres del teixit que han estat impregnades amb glicerol i aigua, avaluant així la permeabilitat del PET amb glicerol. A més, s’han realitzat els tractaments a mostres impregnades amb glicerol i NaOH per tal de comprovar si l’hidròxid de sodi, degut a la seva facilitat per adherir-se a les fibres, segons estudis realitzats [2], millora la penetració del glicerol i s’obtenen millors resultats. Els tractaments utilitzats són per esgotament en bany termoestàtic de va-i-ve a 40ºC durant una hora, i per microones, estudiant també un possible pretractament amb plasma de corona. Uno de los tejidos actuales más utilizados en la industria textil es el poliéster (PET), tanto por sus propiedades físicas y químicas, como por su coste asequible para todos. Sin embargo, es un material hidrófobo, por tanto, no transporta ni dispersa el agua líquida liberada del cuerpo. La eliminación de calor y agua del cuerpo permite mejorar el nivel de confort. Por lo tanto, si la transpiración queda atrapada a ras o cerca de la piel, puede provocar un aumento de la temperatura corporal, causando deshidratación, fatiga y disminución del rendimiento. [1] Es por ello por lo que, actualmente se están realizando experimentos para mejorar esta propiedad del PET mediante la modificación superficial del tejido. En este proyecto se pretende aumentar el bienestar y el confort del PET aumentando su hidrofilidad con la modificación de la superficie de este. Por ello, se han aplicado tres tratamientos diferentes a muestras del tejido que han sido impregnadas con glicerol y agua, evaluando así la permeabilidad del PET con glicerol. Además, se han realizado los tratamientos a muestras impregnadas con glicerol y NaOH para comprobar si el hidróxido de sodio, debido a su facilidad para adherirse a las fibras, según estudios realizados [2], mejora la penetración del glicerol y se obtienen mejores resultados. Los tratamientos utilizados son por agotamiento en baño termostático de va-y-ven a 40ºC durante una hora, y por microondas, estudiando también un posible pretratamiento con plasma de corona. One of the most used fabrics in the textile industry today is polyester (PET), because of its physical and chemical properties and for its affordable cost for everybody. However, it is a hydrophobic material, therefore it does not transport or disperse the liquid water released from the body. The elimination of heat and water from the body improves the comfort level. Therefore, if perspiration is trapped close to the skin, it can cause an increase in body temperature, causing dehydration, fatigue, and decreased performance. [1] That is why, currently, experiments are being carried out to improve this property of PET by superficial modification of the tissue. This project aims to increase the well-being and comfort of PET by increasing its hydrophilicity by modifying its surface. For this reason, three different treatments have been applied to tissue samples that have been impregnated with glycerol and water, thus evaluating the permeability of PET with glycerol. In addition, treatments have been carried out on samples impregnated with glycerol and NaOH to check whether sodium hydroxide, due to its ease of adhering to fibers, according to studies [2], improves the penetration of glycerol and better results are obtained. The treatments used are by exhaustion bath at 40ºC for one hour, and by microwave, also studying a possible pre-treatment with corona plasma.

262 p. The overall objective of this work was to study the suitability of Poly Lactic Acid (PLA) and starch containing natural agents, as active packaging. For this, we chose several natural actives substances such as essential oils and plant extracts of rosemary, myrtle, thyme and pistachio tree to produce an active food packaging. Firstly, composition analyses, as well as a phytochemical and biological characterization of these actives substances were elaborated. Secondly, the mode of inclusion of these active agents in PLA and starch matrices and also their potential effects on diverse optical, thermal, mechanical and barrier properties of PLA and starch were investigated. An evaluation of the antifungal and antioxidant activities of these films was studied. Then, a study of the release of the active agents was accomplished from PLA and starch films in contact with a food simulant. The results showed that PLA has the capacity to contain natural active substances and protect food from microbial spoilage. Also, the thermal, the mechanical, and the water vapor barrier properties of PLA were enhanced by the incorporation of commercials essential oils of rosemary (0.5%) and thyme (0.5% and 5%) and the ethyl acetate extracts of thyme (0.5%) and myrtle (0.5% and 1.5%). The incorporation of thyme commercial essential oil into starch film-forming solution, has improved the mechanical and the barriers properties. PLA films containing essential oils and plant extracts have shown promising results to be applied as active food packaging, since they have enhanced the antifungal and antioxidant properties of PLA.

Cyclic oligomers of isomannide 2,5-furandicarboxylate were synthesized using the high dilution condensation method. A mixture of dimer, trimer, and tetramer species largely enriched in dimer was obtained. These cyclic oligomers were made to react with oligo(butylene 2,5-furandicarboxylate) in bulk at 220 °C by ring opening polymerization using Sn(Oct)2 as a catalyst. A series of random poly(butylene 2,5-furandicarboxylate) copolyesters containing isomannide in a range of 5–50 mol % and with weight-average molecular weights between 30,000 and 50,000 g·mol–1 were prepared. These copolyesters started to decompose above 300 °C, and only those containing less than 10 mol % of isomannide showed signs of crystallinity. They displayed glass-transition temperatures in the 40–100 °C range with values increasing steadily with the content in isomannide. At difference with poly(butylene 2,5-furandicarboxylate) homopolyester that is reluctant to undergo hydrolysis, the isomannide-containing copolyesters were noticeably degraded by water, much more rapidly when exposed to lipases.

The evaluation of the performance of polyesters under in vitro physiologic conditions is essential to design scaffolds with an adequate lifespan for a given application. In this line, the degradation-durability patterns of poly(lactide-co-glycolide) (PLGA), polydioxanone (PDO), polycaprolactone (PCL) and polyhydroxybutyrate (PHB) scaffolds were monitored and compared giving, as a result, a basis for the specific design of scaffolds from short-term to long-term applications. For this purpose, they were immersed in ultra-pure water and phosphate buffer solution (PBS) at 37 &deg, C. The scaffolds for short-time applications were PLGA and PDO, in which the molar mass diminished down to 20% in a 20&ndash, 30 days lifespan. While PDO developed crystallinity that prevented the geometry of the fibres, those of PLGA coalesced and collapsed. The scaffolds for long-term applications were PCL and PHB, in which the molar mass followed a progressive decrease, reaching values of 10% for PCL and almost 50% for PHB after 650 days of immersion. This resistant pattern was mainly ascribed to the stability of the crystalline domains of the fibres, in which the diameters remained almost unaffected. From the perspective of an adequate balance between the durability and degradation, this study may serve technologists as a reference point to design polyester-based scaffolds for biomedical applications.

Cyclic oligomers of hexamethylene furanoate and hexamethylene terephthalate were obtained from 1,6-hexanediol and the corresponding methyl esters using Candida antarctica lipase B (CALB) enzyme catalyst. HPLC, MALDI-TOF MS, and NMR analyses showed that mixtures composed from cyclic dimer up to heptamer were obtained almost quantitatively. Subsequently, these cycles were polymerized by ring opening polymerization (ROP) mediated by CALB to obtain semicrystalline polymers. In addition, we demonstrated that the polymers obtained from the ROP process could be transformed into cyclic oligomers in high yields using enzymatic cyclodepolymerization, thereby recycling the polymer in a circular biosynthetic path.

Sugar-based polyesters derived from sorbitol and isohexides were obtained via solvent-free enzymatic catalysis. Pendant hydroxyl groups, coming from the sorbitol units, were present along the polyester backbone, whereas the two isohexides, namely, isomannide and isoidide dimethyl ester monomers, were selected to introduce rigidity into the polyester chains. The feasibility of incorporating isomannide as a diol compared to the isoidide dimethyl ester as acyl-donor via lipase-catalyzed polycondensation was investigated. The presence of bicyclic units resulted in enhanced Tg with respect to the parent sorbitol-containing polyester lacking isohexides. The different capability of the two isohexides to boost the thermal properties confirmed the more flexible character provided by the isoidide diester derivative. Solvent-borne coatings were prepared by cross-linking the sugar-based polyester polyols with polyisocyanates. The increased rigidity of the obtained sugar-based polyester polyols led to an enhancement in hardness of the resulting coatings.

Gramicidin (GA), a very hydrophobic pentadecapeptide with important biological activities (i.e. in addition to its well-known antimicrobial and antibiotic activities, GA has been recently identified as a potent therapeutic agent against different carcinomas), has been loaded by electrospraying in poly(tetramethylene succinate) (PE44), a biodegradable and biocompatible aliphatic polyester. Microspheres (average diameter: 5.0 ± 0.7 μm) were successfully obtained from the mixture of GA and PE44 solutions in ethanol and chloroform, respectively. The loading of the peptide, which has been proved by FTIR and X-ray photoelectron spectroscopies, essentially occurred at the surface of the microspheres, as was reflected by scanning electron microscopy micrographs and atomic force microscopy phase images. In spite of this, the thermal stability of the polyester matrix remained essentially unaltered, even though the wettability decreased. The release of GA in phosphate buffer saline (PBS) was limited by the very low solubility of the peptide in aqueous solution, a fast burst effect followed by the establishment of equilibrium after 5 days of being observed in this hydrophilic environment. The release behaviour was very different when the hydrophilicity of the medium was reduced by adding ethanol. In this case, a very fast but sustained release was identified during the first few hours. On the other hand, biological tests have demonstrated that GA retains its antimicrobial activity after loading and does not alter the biocompatibility of PE44. Our results prove that, despite its hydrophobicity and relatively large number of residues, the loading of GA in a polymeric matrix represents an alternative strategy for the release of this versatile peptide in cancer therapy., Authors thank supports from MINECO and FEDER (MAT2015-69367-R, MAT2015-69547-R and CTQ2013-40855-R) and Gobierno de Aragón – Fondo Social Europeo (research group E40). Support for the research of C.A. was received through the prize “ICREA Academia” for excellence in research funded by the Generalitat de Catalunya.

Microfibras de poli(éster amida) y poli(éster urea) – biodegradables y derivadas de αaminoácidos – fueron preparadas e investigadas para contribuir en la investigación de polímeros para biomedicina. Las fibras electrohiladas se obtuvieron a partir de los mencionados polímeros, de sus blends y copolímeros de diferentes composiciones, una vez fueron optimizados los parámetros del proceso para conseguir un flujo continuo de polímero, y por consiguiente, fibras de calidad a escala microscópica. Además, se ensayó la incorporación de un bio-fármaco, en concreto la enzima lisozima, para la construcción de una matriz con actividad antibacteriana con resultados positivos ante una bacteria gram-positiva (S. aureus), aunque no se observó la misma efectividad contra una bacteria gram-negativa (E. coli). Asimismo, las propiedades de las fibras no cambiaron con la incorporación de esta enzima. Para verificar la composición de los blends preparados y confirmar la presencia de los enlaces principales en estos polímeros se realizaron técnicas de caracterización espectroscópica. Conjuntamente, fueron necesarios análisis térmicos para determinar la temperatura de transición vítrea y así descubrir la razón por la cual algunas de las matrices fibrosas cambiaron su morfología a films. Las medidas del ángulo de contacto manifestaron propiedades superficiales muy distintas, donde las matrices con fibras mostraron una alta hidrofobicidad y aquellas que se convirtieron en films resultaron más hidrofílicas.

Cyclic butylene furandicarboxylate (c(BF)n) and butylene isophthalate (c(BI)n) oligomers obtained by high dilution condensation reaction were polymerized in bulk at 200 °C with Sn(Oct)2 catalyst via ring opening polymerization to give homopolyesters and copolyesters (coPBFxIy) with weight average molar masses in the 60,000–70,000 g·mol−1 range and dispersities between 1.3 and 1.9. The composition of the copolyesters as determined by NMR was practically the same as that of the feed, and they all showed an almost random microstructure. The copolyesters were thermally stable up to 300 °C and crystalline for all compositions, and have Tg in the 40–20 °C range with values decreasing almost linearly with their content in isophthalate units in the copolyester. Both melting temperature and enthalpy of the copolyesters decreased as the content in butylene isophthalate units increased up to a composition 30/70 (BF/BI), at which the triclinic crystal phase made exclusively of butylene furanoate units changed to the crystal structure of PBI. The partial replacement of furanoate by isophthalate units decreased substantially the crystallizability of PBF.

El gran desenvolupament que actualment estan experimentant els biopolímers es deu fonamentalment als alts preus i a la disminució de les reserves de petroli, juntament amb la preocupació que existeix avui en dia en matèria de sostenibilitat ambiental. Entre els polímers d'origen renovable, els polièsters alifàtics són dels més estudiats ja que es consideren molt adequats per aplicacions com a biomaterials a causa de la seva biocompatibilitat i biodegradabilitat. En aquesta tesi s'han preparat polièsters renovables mitjançant química sostenible i utilitzant derivats de l'oli de ricí, com a producte de partença. Concretament, s'han fet servir reaccions amb àcid 10-undecenoïc per obtenir els monòmers, que contenen grups funcionals àcid carboxílic i epòxid o alcohol. Tots dos tipus de monòmer són capaços d'experimentar polimerització, obtenint així polímers lineals i ramificats amb grups hidroxilo funcionalitzables. S'ha demostrat que aquests polímers són degradables enzimàtica i hidrolíticament. A més a més s'han modificat aquests polièsters amb diferents biomolècules com els aminoàcids. Finalment, utilitzant enzims com a catalitzador s'han sintetitzat copoliésters de bloc i d’empelt a partir d'aquests monòmers o polièsters i derivats del polietilenglicol. Com a resultat s’han obtingut polímers amfifílics capaços de formar micel·les en les quals és possible encapsular drogues per ser alliberades de forma controlada. El gran desarrollo que están experimentando actualmente los biopolímeros se debe fundamentalmente a los altos precios y disminución de las reservas de petróleo, junto con la preocupación que existe hoy en día en materia de sostenibilidad ambiental. Entre los polímeros de origen renovable los poliésteres alifáticos son los que se han estudiado en mayor profundidad por ser los más adecuados como biomateriales, debido a su biocompatibilidad y biodegradabilidad. En esta tesis se han preparado poliésteres renovables mediante química sostenible y el uso de derivados de aceite de ricino como materia de partida. Concretamente, se han usado reacciones a partir del ácido 10-undecenoico para obtener monómeros que contienen grupos funcionales ácido carboxílico y epóxido o alcohol. Ambos monómeros son capaces de experimentar polimerización, obteniendo así polímeros lineales y ramificados con grupos hidroxilo funcionalizables. Se ha demostrado que estos polímeros son degradables enzimática e hidrolíticamente. Además, estos poliésteres se han modificado con diferentes biomoléculas como aminoácidos. Finalmente, utilizando enzimas como catalizador se han sintetizado copoliésteres de bloque y de injerto a partir de estos monómeros o poliésteres y derivados del polientilenglicol. Como resultado, se han obtenido polímeros amfifílicos capaces de formar micelas, en las cuales es posible encapsular drogas para ser liberadas de forma controlada. Currently biopolymers experienced a great development due to the high prices and decrease of petroleum reserves along with the concern increasing in terms of environmental sustainability. Aliphatic polyesters are among the most studied polymers from renewable resources, because they are considered very suitable for applications as biomaterials due to their biocompatibility and biodegradability. In this thesis, renewable polyesters have been prepared from derivatives of vegetable castor oil and using sustainable chemistry. Specifically, 10-undecenoic acid has been used to synthesize the monomers which contain carboxylic acid and epoxide or alcohol. These monomers by polymerization lead to linear or branched polymers with available reactive hydroxyl groups. It has been shown that these polymers are enzymatically and hydrolytically degradable. In addition, these polyesters have been modified with different biomolecules as aminoacids. Finally, using enzymes as catalyst have been synthesized block and grafted copolyesters from these monomers or polyesters and polyethylene glycol derivatives. As result, amphiphilic polymers capable of forming micelles have been synthesized, which can encapsulate drugs to be released.

44 p.-6 fig.-2 tab.-5 fig.supl., Polyhydroxyalkanoates (PHAs) are biodegradable polyesters that accumulate in the cytoplasm of certain bacteria. One promising biotechnological application of these biopolymers contemplates its utilization as supports for protein immobilization. Here, the PHA-binding domain of the Pseudomonas putida KT2440 PhaF phasin (BioF polypeptide) was investigated as affinity tag for in vitro functionalization of poly-3-hydroxybutyrate (PHB) particles with recombinant proteins, namely full-length PhaF and two fusion proteins tagged to BioF (BioF-C-LytA and BioF- β-galactosidase, containing the choline-binding module C-LytA and the β-galactosidase enzyme, respectively). Protein-biopolyester interaction was strong and stable in a wide range of pH and temperature, and the bound protein was highly protected from self-degradation, while binding strength could be modulated upon particle coating with amphiphilic compounds. Finally, a mini-bioreactor with immobilized BioF- β-galactosidase displayed a very stable enzymatic activity after several continuous activity+washing cycles. Our results demonstrate the potentialities of PHA and the BioF tag for the construction of novel bioactive materials., Importance: Our results confirm the biotechnological potential of the BioF affinity tag as a versatile tool for functionalizing PHA supports with recombinant proteins, leading to novel bioactive materials. The BioF tag wide substrate range presumably allows protein immobilization in vitro to virtually all natural PHAs as well as blends, copolymers or artificial, chemically-modified derivatives with novel physical-chemical properties. Moreover, the strength of protein adsorption may be easily modulated by varying the coating of the support, providing new perspectives for the engineering of bioactive materials that require a tight control of protein loading., This work was supported by Spanish Ministry of Economy and Competitiveness (grants BFU2010-17824, BIO2013-44878-R, BIO2013-47684-R and BIO2016-79323-R) and Community of Madrid (Spain) (NanoBIOSOMA S20 1473 3/M lT-2807)

En la actualitat, els poliuretans i els polièsters són dos dels materials polimèrics més importants ia que se poden utilitzar en multitud de camps donada la seva versatilitat. Els últims avenços en la investigació sobre aquest tipus de polímers venen donats per la creixent demanda de processos més sostenibles i l'ús de matèries primeras d'origen renovable. Algunes d'aquestes són els olis vegetals, com l'oli de ricí el qual no és apte per el consum humà. A partir d'aquest oli, s'obté l'àcid ricinoleic amb un rendiment elevat. Aquest àcid es converteix mitjançant piròlisi en àcid undecenoic i heptanal. L'àcid undecenoic ha estat àmpliament utilitzat per a la síntesi de diferents monòmers i polímers amb elevats rendiments i sostenibilitat química. En canvi el heptanal, apreciat per les qualitats olfactives d'alguns dels seus derivats, és àmpliament utilitzat com un intermediari de síntesi per a la indústria de fragàncies i aromes. Malgrat l'ús d'aquest compost com a producte intermedi químic en la química de polímers és pràcticament inexistent. En la present tesi s'ha investigat una àmplia varietat de transformacions químiques per obtenir monòmers bifuncionals i renovables així com els seus polièsters i poliuretans, utilitzant heptanal com a matèria primera. Tanmateix, s'han desenvolupat diferents nanosistemes basats en aquests polímers com són micel·les o nanocàpsules. Com a conclusió general, s'ha demostrat que la transformació de l'heptanal en monòmers i polimers mitjançant processos mediambientalment compatibles és una alternativa sostenible en química de polimers. En la actualidad, los poliuretanos y los poliésteres son dos de los materiales poliméricos más importantes ya a que se pueden utilizar en multitud de areas debido a su versatilidad. Los últimos avances en la investigación sobre este tipo de polímeros son impulsados por la creciente demanda de procesos más sostenibles y el uso de materias primas renovables. Algunas de estas materias primas renovables son los aceites vegetales, como el aceite de ricino el cual no es comestible. A partir de este aceite, se obtiene el ácido ricinoleico con un alto rendimiento. Este ácido se convierte mediante pirólisis en ácido undecenoico y heptanal. El ácido undecienoico ha sido ampliamente utilizado para la síntesis de diferentes monómeros y polímeros con elevados rendimientos y sostenibilidad química. En cambio el heptanal, apreciado por las cualidades olfativas de algunos de sus derivados, es ampliamente utilizado como un intermediario de síntesis para la industria de fragancias y aromas. Sin embargo, el uso de este compuesto como producto intermedio químico en la química de polímeros es prácticamente inexistente. En esta tesis se ha investigado una amplia variedad de transformaciones químicas para obtener monómeros bifuncionales y renovables así como sus poliésteres y poliuretanos, utilizando heptanal como materia prima. Además, se desarrollaron diferentes nanosistemas basados en estos polímeros como son micelas o nanocápsulas. Como conclusión general, se ha demostrado que la transformación de heptanal en monómeros y polimeros mediante procesos mediambientalmente compatibles es una alternativa sostenible en química de polimeros. Nowadays, polyurethanes and polyesters are two of the most important polymeric materials that can be used in different applications due to their versatility. The recents advances in the research of these kinds of polymers are driven by the growing demand for greener processes and the use of renewable raw materials. Some of these renewable raw materials are vegetable oils, such as non-edible castor oil. From this oil, ricinoleic acid is obtained in a high yield. Ricinoleic acid is converted by chemical thermal cracking process into undecenoic acid and heptanal. Undecenoic acid has been widely used for the synthesis of different monomers and polymers combining high performance and sustainability. Heptanal, appreciated for the olfactory qualities of certain of its derivatives, is widely used as a synthesis intermediate for fragrance and aroma industry. However, the use of C7 cut of castor oil thermal cracking as a chemical intermediate in polymer chemistry is practically non-existent. In this thesis, we have explored a wide variety of chemical transformations to obtain bifunctional biobased monomers and their polyesters and polyurethanes, using heptanal such as raw material. Furthermore, the development a novel nanoparticles with some of these materials was carried out. As a general conclusion, the transformation of heptanal into monomers and polymers using environmentally friendly procedures has been shown to be a sustainable alternative in polymer chemistry.

In the present study poly (butylene sebacate- co -terephthalate)s having different compositions were synthesized with a high yield and a random distribution by thermal transesterification of poly (butylene sebacate) and poly (butylene terephthalate) homopolymers. The copolymer with the highest comonomer ratio was the least crystalline sample, although the melting peaks corresponding to both, sebacate and terephthalate-rich phases were still observable in calorimetric heating runs. This copolymer was associated with interesting thermal and mechanical properties, as the maximum melting point was higher than 100 °C and the storage modulus was also high (i.e. 1.1 × 10 9 N/m 2 and 1.7 10 8 N/m 2 were determined just before and after the main glass transition temperature of −12 °C). As all studied samples were thermally stable up to temperatures clearly higher than the fusion temperature, they could be easily processed. Increasing the terephthalate content of the copolymers resulted in higher hydrophobicity, which had a minor influence on cell adhesion and proliferation of both fibroblast-like and epithelial-like cells. Hydrolytic and enzymatic degradability were assessed and the effect of composition and crystallinity on the degradation rate was investigated. Molecular weight measurements during exposure to a hydrolytic media indicated a first order kinetic mechanism during the initial stages of degradation before reaching a limiting molecular size, which was indicative of solubilization. The most amorphous sample appears as a highly promising biodegradable material since it showed a significant weight loss during exposure to all selected degradation media, but also exhibited good performance and properties that were comparable to those characteristic of polyethylene.

Poly(ethylene succinate) (PES) with weight-average molecular weight above 60,000 g mol-1 was efficiently obtained by enzymatic ring opening polymerization of cyclic oligo(ethylene succinate)s c(ES)n, which in turn were prepared by lipase-catalysed cyclocondensation in solution of dimethyl succinate and ethylene glycol. The methodology was demonstrated to be also applicable to the synthesis of high molecular weight PES-copolyesters containing butylene succinate, e-hydroxycaproate or L-lactate units with a random distribution.

New biodegradable polymeric materials have been developed in order to minimize the environmental impact caused by the traditional packaging found in the market. Polyhydroxyalkanoates (PHAs) are biopolymers with important features such as biodegradability and biocompatibility; however, the costs associated with PHAs production and the limited mechanical properties reduce their application. Whey is a residual product from dairy industry and gelatin is a biopolymer with good processing characteristics. In this context, a filmogenic solution based on these two biopolymers was incorporated into pure PHA films to improve their optical, mechanical, and structural properties. The filmogenic solution was prepared from gelatin, cheese whey and PHAs, using glycerol as plasticizer agent. The multilayers films (gelatin concentrations at 3 and 5%, w/v) showed higher values for all properties when compared with the PHA standard film. In this sense, the addition of this solution was responsible for the improvement of the film properties. The 5% gelatin multilayers films added of cheese whey and PHAs showed better results when compared with the multilayers films with gelatin at 3%. The film composed of gelatin 5% and cheese whey showed a water vapor permeability ranging from 0.45 g mm/m2/d/kPa, elongation of 2.18%, and opacity of 14.5%. However, the results of the morphological analysis showed that both films presented a homogeneous surface without cracks. Moreover, the results of the thermal analysis of both films indicate polymeric miscibility. Thus, the choice of the best film will depend on its applicability. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44458.

Three series of polyalkanoates (adipates, suberates and sebacates) were synthesized using as monomers three sugar-based bicyclic diols derived from D-glucose (Glux-diol and isosorbide) and D-mannose (Manx-diol). Polycondensations were conducted in the melt applying similar reaction conditions for all cases. The aim was to compare the three bicyclic diols regarding their suitability to render aliphatic polyesters with enhanced thermal and mechanical properties. The ensuing polyesters had molecular weights (Mw) in the 25,000–50,000 g mol-1 range with highest values being attained for Glux-diol. All the polyesters started to decompose above 300 °C and most of them did not display perceivable crystallinity. On the contrary, they had glass transition temperatures much higher than usually found in homologous polyesters made of alkanediols, and showed a stress– strain behavior consistent with their Tg values. Glux-diol was particularly effective in increasing the Tg and to render therefore polyesters with high elastic modulus and considerable mechanical strength.

The synthesis, characterization and comparative evaluation of properties of two series of cationic PBS copolyesters bearing respectively ammonium and tributylphosphonium side groups, are reported. The copolyesters with contents in ionic units up to 50 mole-% as well as the fully ionic homopolyesters were prepared by polycondensation in the melt catalyzed by CALB or TBT. Their Mn ranged between 20,000 and 5000 g mol-1 depending of composition and the type of ionic group that is involved. All the copolyesters were non-water soluble and showed good thermal stability. They were semicrystalline with melting temperatures and enthalpies decreasing with the ionic contents. The interactions interplayed by the ionic groups restricted largely the molecular mobility and caused a significant increase in the melt viscosity and glass transition temperature of PBS and a decrease in crystallization rate. Both ammonium and phosphonium containing PBS copolyesters were able to be coupled with sulfonated PBS to generate ionic polymer blends with modified crystallizability. The presence of both ammoniums and phosphoniums provided PBS with remarkable antimicrobial activity against gram-positive and gram-negative bacteria.

In this communication we wish to report on the synthesis of PBFxSy copolyesters by ring opening polymerization (ROP) using either organometallic catalysts or enzymes. The ROP of macrocyclic oligomers (MCOs) has been demonstrated to offer significant advantages over the traditional polycondensation method. The synthesis of MCOs of butylene succinate c(BS)n is known from long whereas MCOs of butylene 2,5-furandicarboxylate (c(BF)n) have not been reported until very recently. In this work, the synthesis of c(BF)n and c(BS)n has been performed using high dilution condensation (HDC) and enzymatic cyclization, respectively. Mixtures of dimer to tetramer and dimer to nonamer were obtained for c(BF)n and c(BS)n respectively.

In this work we have prepared and compared the thermal and mechanical properties of aliphatic polyesters made from aliphatic diacids with different polymethylene chain lengths (2, 4, 6, 8) and three bicyclic sugar derived diols namely, dianhydro-1,4:3,6-D-glucitol (also known as isosorbide, Is), and two bicyclic diazetalized hexitols, 2,4:3,5-di-O-methylene- D-mannitol (Manx-diol) and -D-glucitol (Glux-diol) derived from D-mannose and D-glucose respectively (Fig. 1)

Bacterial polyesters such as polyhydroxyalkanoates (PHAs) are of great interest for a large number of applications both because of their properties and because they come from renewable resources, despite having a higher cost than commodity polymers. Their foaming—although it presents some difficulties—could be an option to increase their competitiveness. In this work, two strategies have been studied to enhance the poly(3-hydoxybutyrate-co-4-hydroxybutyrate) (P3HB4HB) foamability by extrusion foaming. The effect of the cooling system (water-quenching or air-cooling), chain extender (CE) addition and chemical blowing agent (CBA) amount were evaluated. Density, cellular morphology, mechanical and thermal properties were studied. Optimal density reduction was achieved with use of CE and 3–4 wt.% of CBA masterbatch. The most effective strategy on density reduction was the addition of CE, while the water quenching had only a slight influence on the samples in which CE was not present. CE addition decreased the viscosity and the degradation rate of the polymer, thus leading to lighter foams with larger cells but with equal or even slightly better resistance to compressive and tensile stress, in general terms.

Copolyesters derived from 1,4-butanediol and constituted also of aliphatic and aromatic dicarboxylate units in a molar ratio of 3:7 were synthesized by a two-step polycondensation procedure. Succinic, adipic, and sebacic acids were specifically selected as the aliphatic component whereas terephthalic acid was chosen as the aromatic moiety. The second synthesis step was a thermal transesterification between the corresponding homopolymers, always attaining a random distribution as verified by NMR spectroscopy. Hybrid polymer composites containing 2.5 wt % of hydroxyapatite (HAp) were also prepared by in situ polymerization. Hydroxyl groups on the nanoparticle surface allowed the grafting of polymer chains in such a way that composites were mostly insoluble in the typical solvents of the parent copolyesters. HAp had some influence on crystallization from the melt, thermal stability, and mechanical properties. HAp also improved the biocompatibility of samples due to the presence of Ca2+ cations and the damping effect of phosphate groups. Interestingly, HAp resulted in a significant increase in the hydrophilicity of samples, which considerably affected both enzymatic and hydrolytic degradability. Slight differences were also found in the function of the dicarboxylic component, as the lowest degradation rates was found for the sample constituted of the most hydrophobic sebacic acid units. View Full-Text

Entropically driven ring-opening copolymerization of mixtures of a fraction of cyclic oligo(hexamethylene terephthalate)s composed of cycle sizes from 2 to 5 and p-dioxanone was used to prepare random copolyesters covering a range of aromatic (HT) to aliphatic (DO) units ratios from 9 to 1.3. The composition and microstructure of the copolyesters were accurately determined by 1H and 13C NMR, respectively. The copolyesters showed thermal degradation and glass transition temperatures in good agreement with their comonomeric composition and microstructure, and they crystallized for contents in DO less than 30%, adopting the same crystal structure as poly(hexamethylene terephthalate). The copolyesters appeared to be sensitive to hydrolytic degradation, which was observed to take place superficially with the generation of non-water-soluble degraded fragments and with the release of water-soluble dioxanoic acid to the aqueous medium.

Multifunctional electrospun scaffolds were prepared from two polylactide (PLA) grades having slightly different d-lactide content (4.2 wt % and 2.0 wt %). Triclosan (TCS), ketoprofen (KTP), and p-coumaric acid (CUM) were selected as bactericide, anti-inflammatory, and antioxidant agents, respectively. Single, binary, and ternary drug-loaded microfibers having a unimodal diameter distribution could be prepared using a common chloroform:acetone:dimethylsulfoxide mixture and similar operational parameters (i.e., voltage, flow rate, and tip-collector distance). FTIR spectra were sensitive to the low amount of drugs loaded and even showed slight differences in PLA conformation. DSC heating scans clearly demonstrated the ability of electrospinning to induce molecular orientation of PLA and also the nucleation effect of incorporated drugs to induce crystallization. Thus, crystallinity of binary drug-loaded scaffolds was significantly higher than observed for unloaded samples. Release behavior of the three drugs from loaded scaffolds and PLA matrices in PBS:ethanol medium was evaluated. A rapid release was always detected, together with partial drug retention which was higher when the more stereoregular PLA matrix was employed. A strong bactericidal effect was found when scaffolds were loaded with 3 wt/vol % of TCS, but incorporation of a small percentage of KTP (i.e., 1 wt/vol %) had a bacteriostatic effect even in the absence of TCS. The inherent cytotoxicity of TCS could be well neutralized by enhancing cell viability by incorporation of CUM and/or KTP. Multifunctional electrospun scaffolds were prepared from two polylactide (PLA) grades having slightly different d-lactide content (4.2 wt % and 2.0 wt %). Triclosan (TCS), ketoprofen (KTP), and p-coumaric acid (CUM) were selected as bactericide, anti-inflammatory, and antioxidant agents, respectively. Single, binary, and ternary drug-loaded microfibers having a unimodal diameter distribution could be prepared using a common chloroform:acetone:dimethylsulfoxide mixture and similar operational parameters (i.e., voltage, flow rate, and tip-collector distance). FTIR spectra were sensitive to the low amount of drugs loaded and even showed slight differences in PLA conformation. DSC heating scans clearly demonstrated the ability of electrospinning to induce molecular orientation of PLA and also the nucleation effect of incorporated drugs to induce crystallization. Thus, crystallinity of binary drug-loaded scaffolds was significantly higher than observed for unloaded samples. Release behavior of the three drugs from loaded scaffolds and PLA matrices in PBS:ethanol medium was evaluated. A rapid release was always detected, together with partial drug retention which was higher when the more stereoregular PLA matrix was employed. A strong bactericidal effect was found when scaffolds were loaded with 3 wt/vol % of TCS, but incorporation of a small percentage of KTP (i.e., 1 wt/vol %) had a bacteriostatic effect even in the absence of TCS. The inherent cytotoxicity of TCS could be well neutralized by enhancing cell viability by incorporation of CUM and/or KTP.

El desenvolupament de nous biopolímers ha esdevingut un tema de gran interes, degut tant a la disminució de les reserves de petroli i el seu preu com als problemes derivats de la sostenibilitat mediambiental. A banda dels benificis mediambientals que suposen, l’aplicacio de la quimica click permet la transformació eficient d’aquests materials. Un tipus particular de polímers renovables son els poliesters alifátics, que son adequats en moltes aplicacions donada la seva biocompatibilitat i biodegradabilitat. En aquesta tesi s’han preparat poliesters emprant oils vegetals con l’oli de rici i l’oli de girasol i amb l’aplicacio de la química click. En particular, s’han aplicat les adicions tiol-è i tiol-í als l’àcid 10-undenoic i 10-undecinoic, derivats de l’oli de rici, per obtenir monomers de condensació que contenen funcionalitats tioèter i vinilsulfur respectivament. L’addició tio-Michael s’ha aplicat a l’enona de l’oleat de metil, derivada del oli de girasol per obtenir un monomer hidroxiester que conté un grup cetona. A partir d’aquests monomers i de bioplastics ja desenvolupats com l’acid polilàctic o la caprolactona s’han desenvolupat copolímers a l’atzar i de bloc les propietats dels quals els fan una alternativa per aquests materials convencionals. Finalment, la modificació d’aquests nous poliesters permet l’acces a un ventall de poliesters funcionalitzats., El gran desarrollo que están experimentando actualmente los biopolímeros se debe fundamentalmente a los altos precios y disminución de las reservas de petroleo junto con la preocupacion que existe hoy en dia en materia de sostenibilidad ambiental. Por otra parte, además de sus beneficios medioambientales, se puede aprovechar la química “click” para una transformación eficiente de estos materiales. Entre los polímeros de origen renovable los poliésteres alifáticos están entre los más estudiados por ser considerados muy adecuados para aplicaciones como biomateriales debido a su biocompatibilidad y biodegradabilidad. En esta tesis, se han preparado poliésteres renovables combinando la utilización de aceites vegetales (ricino y girasol) y química “click”. En particular, se han usado reacciones de acoplamiento tiol-eno y tiol-ino con los ácidos 10-undecenoico y 10-undecinoico, para obtener monómeros de condensación que contienen funcionalidades tioéter y sulfuro de vinilo respectivamente. La adición tio-Michael se aplicó a un derivado del aceite de girasol, el oleato de metilo que contiene un grupo funcional enona, para obtener un monómero hidroxiéster con grupos cetona, capaz de experimentar policondensación. Además, se han sintetizado copoliésteres al azar y en bloque a partir de estos monómeros y ácido poliláctico y policaprolactona para obtener materiales cuyas propiedades les convierten en una alternativa a estos poliésteres convencionales. Por último la modificación de estos materiales permite acceder a una gran variedad de poliésteres funcionalizados., The development of biobased polymers is nowadays attracting a great deal of interest due to the high price and future depletion of fossil fuel stocks, together with concerns regarding environmental sustainability. Moreover, besides their sustainability benefits, taking advantage of click chemistry allows for the efficient transformation of these materials. One particular class of renewable polymers is aliphatic polyesters that are generally considered to be well suited for applications as polymer-based biomaterials due to their biocompatibility and biodegradability. In this thesis, we have prepared renewable polyesters taking into advantage of collaboration between vegetable oils (castor and sunflower oils) and click chemistry. In particular, thiol-ene and thiol-yne reactions were applied to the castor oil derivatives, 10-undecenoic acid and 10-undecynoic acid, to obtain condensable monomers containing thioether and vinylsulfide functionalities respectively. Thiol-Michael addition was applied to a sunflower oil derivative, enone-containing methyl oleate, to synthesize a polycondensation hydroxyester monomer with ketone functionality. In addition, several random and block copolyesters from these monomers and biobased plastics such as poly(lactide) (PLA) and poly(ε-caprolactone) (PCL) have been developed with potential as these conventional analogues. Finally, the postpolymerization modifications of the polyesters allowed to develop a platform of functionalized polyesters.

Biotechnologically accessible 1,4-butanediol and vegetal oil-based diethyl sebacate were copolymerized with bicyclic acetalized d-glucose derivatives (Glux) by polycondensation both in the melt at high temperature and in solution at mild temperature mediated by polymer-supported Candida antarctica lipase B (CALB). Two series of random copolyesters (PBxGluxySeb and PBSebxGluxy) were prepared differing in which d-glucose derivative (Glux diol or Glux diester) was used as comonomer. The three parent homopolyesters PBSeb, PBGlux, and PGluxSeb were prepared as well. Both methods were found to be effective for polymerization although significant higher molecular weights were achieved by melt polycondensation. The thermal properties displayed by the copolyesters were largely dependent on composition and also on the functionality of the replacing Glux unit. The thermal stability of PBSeb was retained or even slightly increased after copolymerization with Glux, whereas crystallinity and melting temperature were largely depressed. On the contrary, the glass-transition temperature noticeably increased with the content in Glux units. PGluxSeb distinguished in displaying both Tg and Tm higher than PBSeb because a different crystal structure is adopted by this homopolyester. The hydrolytic degradability of PBSeb in water was enhanced by copolymerization, in particular, when biodegradation was assisted by lipases.

2,4:3,5-di-O-methylene-D-glucitol (Glux-diol) was used for the synthesis of poly(butylene succinate) (PBS) copolyesters by melt polycondensation. Glux-diol possess a rigid bicyclic asymmetric structure made of two fused 1,3-dioxane rings and two hydroxyl functions at the end positions. Copolyesters were prepared over the whole range of compositions with molecular weights varying from 26 000 to 46 000 g mol-1 and a random microstructure. The thermal stability of PBS did not significantly alter with the presence of Glux units. The glass transition temperatures (Tg) steadily increased from -28 to 80 ºC along the whole copolyester series with the insertion of Glux. On the contrary, melting temperature (Tm) and crystallinity decreased because of the lack of regularity of the polymer chain although copolyesters with contents of Glux units up to 30 mole% were semicrystalline. The stress–strain behavior changed according to variations produced in thermal transitions. The replacement of 1,4-butanediol by Glux-diol slightly increased both the hydrolytic degradability and the biodegradability of PBS. Compared to other bicyclic sugar-based diols reported in the literature, Glux-diol appeared to be more efficient in both increasing the Tg and enhancing the susceptibility to hydrolysis of PBS.

Este proyecto estudia el actual sistema productivo de impresión y laminación de un film de poliéster destinado al sector de la alimentación. La finalidad es determinar aspectos como la viabilidad, capacidad de producción, rendimiento y optimización de recursos. Posteriormente se plantean diversos escenarios que mejoren el proceso productivo actual como la introducción de un nuevo sistema de secado o la puesta en marcha de una ampliación de los equipos del proceso. La metodología empleada ha sido modelizar virtualmente mediante el software SIMIO los diferentes escenarios y posteriormente realizar un estudio económico de cada uno que evalúe la viabilidad de las inversiones propuestas. Se han planteado cuatro escenarios y se ha obtenido que únicamente tres son viables económicamente. Las mejoras introducidas han permitido ampliar la capacidad de producción hasta un 200% para el proceso de impresión y laminación, consiguiendo con esta inversión un VAN a cinco años de 729.674,65€, una TIR del 75,32% y un periodo de retorno de un año y un mes. También se ha realizado un estudio ambiental sobre el actual sistema productivo obteniendo como resultado que este proceso es sostenible ya que los residuos generados son tratados correctamente. Finalmente se ha podido concluir que inversión es la más apropiada según el nivel de producción que se desee alcanzar.

The use of NMR spectroscopy in solution to investigate the chemical structure of engineering poly(alkylene terephthalate)s such as poly(ethylene terephthalate) (PET), poly(trimethylene terephthalate) (PTT), and poly(butylene terephthalate) (PBT) is reviewed. Chemical defects present in the polyester chain, such as oxydialkylene units, as well as accompanying side products such as cyclic oligomers generated in the polycondensation, are well detected in 1H NMR spectra. The technique is also demonstrated to be effective for identifying, and even for quantifying in certain cases, the end groups of these polyterephthalates, including those that are generated in small amounts as a consequence of thermal degradation. The application of NMR to the study of the chemical microstructure of copolyesters derived from such polyterephthalates is also reviewed for its unique ability to determine comonomeric sequence lengths and degree of randomness (R). Copolyesters synthesized by either melt polycondensation or entropically driven ring opening polymerization, in addition to those prepared by solid-state modification or melt blending, are the object of this review.

Electrospun scaffolds from an amino acid containing poly(ester urea) (PEU) were developed as promising materials in the biomedical field and specifically in tissue engineering applications. The selected poly(ester urea) was obtained with a high yield and molecular weight by reaction of phosgene with a bis(alpha-aminoacy1)-alpha,omega-dioldiester monomer. The polymer having L-Ieucine, 1,6-hexanediol and carbonic acid units had a semicrystalline character and relatively high glass transition and melting temperatures. Furthermore it was highly soluble in most organic solvents, an interesting feature that facilitated the electrospinning process and the effective incorporation of drugs with bactericidal activity (e.g. biguanide derivatives such as clorhexidine and polyhexamethylenebiguanide) and enzymes (e.g. alpha-chymotrypsin) that accelerated the degradation process. Continuous micro/nanofibers were obtained under a wide range of processing conditions, being diameters of electrospun fibers dependent on the drug and solvent used.; Poly(ester urea) samples were degradable in media containing lipases and proteinases but the degradation rate was highly dependent on the surface area, being specifically greater for scaffolds with respect to films. The high hydrophobicity of new scaffolds had repercussions on enzymatic degradability since different weight loss rates were found depending on how samples were exposed to the medium (e.g. forced or non-forced immersion). New scaffolds were biocompatible, as demonstrated by adhesion and proliferation assays performed with fibroblast and epithelial cells. (C) 2014 Elsevier B.V. All rights reserved.

2,3-O-Methylene-L-threitol (Thx) is a cyclic carbohydrate-based diol prepared by acetalization and subsequent reduction of the naturally occurring tartaric acid. The structure of Thx consists of a 1,3-dioxolane ring with two attached primary hydroxyl groups. Two series of partially bio-based poly(butylene terephthalate) (PBT) copolyesters were prepared using Thx as a comonomer by melt polycondensation (MP) and solid-state modification (SSM). Fully random copolyesters were obtained after MP using mixtures of Thx and 1,4-butanediol in combination with dimethyl terephthalate. Copolyesters with a unique block-like chemical microstructure were prepared by the incorporation of Thx into the amorphous phase of PBT by SSM. The partial replacement of the 1,4-butanediol units by Thx resulted in satisfactory thermal stabilities and gave rise to an increase of the Tg values, this effect was comparable for copolyesters prepared by MP and SSM. The partially bio-based materials prepared by SSM displayed higher melting points and easier crystallization from the melt, due to the presence of long PBT sequences in the backbone of the copolyester. The incorporation of Thx in the copolyester backbone enhanced the hydrolytic degradation of the materials with respect to the degradation of pure PBT.

Poly(alkylene terephthalate)s, PET and PBT in particular, are materials of great relevance and growing projection in the thermoplastic field but are today almost totally produced from fossil resources. The current huge consumption of these polyesters necessitates urgent actions addressed to make them renewable by using naturally-occurring raw materials. Among the different approaches that are being followed to develop bio-based poly(terephthalate)s, the use of bicyclic carbohydrate-derived difunctional compounds as building-blocks is receiving much attention in the last few years because partially renewable polyesters with high Tg may be thus obtained. This review presents a critical account of the terephthalate homopolymers and copolymers that have been synthesized using the two types of carbohydrate-based bicyclic monomers, isohexides and diacetals, explored to date. The properties displayed by the novel bio-based poly(terephthalate)s in relation to the bicyclic structure of the used monomers are comparatively reviewed and their potential as emergent materials for thermoplastic applications is evaluated.

A series of poly(hexamethylene terephthalate- co -hexamethylene 5-sodium sulfoisophthalate) copolyesters containing from 5 to 50 mol % of sulfonated units as well as the two parent homopolymers are prepared by melt polycondensation. The polyesters are obtained with high molecular weights, which decrease with the increased content of sulfonated units in the copolymer. Polyesters with 5 and 10 mol % of sulfonated units are semicrystalline whereas for contents equal or above 20 mol % they are unable to crystal- lize from the melt. Thermogravimetric analysis show that the thermal stability decreases with the content in sulfonated units. Isother- mal crystallizations of semicrystalline copolyesters show that the insertion of the sulfonated units causes a reduction of crystallizabil- ity, most probably due to the occurrence of ionic aggregations. It is observed a synergistic effect on the mechanical properties for copolymers with contents of around 5 mol % where the elongation at break increases drastically. Moreover, the hydrolytic degrada- tion of the copolymer is enhanced with the content in sulfonated units

The carbohydrate-based diol 2,4:3,5-di- O -methylene- D -mannitol (Manx) has been used to obtain aliphatic polyesters. Manx is a symmetric bicyclic compound consisting of two fused 1,3-dioxane rings and bearing two primary hydroxyl groups. In terms of sti ff ness, it is comparable to the widely known isosorbide, but it a ff ords the additional advantages of being much more reactive in polycondensation and capable of producing stereoregular polymers with fairly high molecular weights. A fully bio-based homopolyester (PManxS) has been synthesized by polycondensation in the melt from dimethyl succinate and Manx. The high thermal stability of PManxS, its relatively high glass transition temperature ( T g =68 ° C) and elastic modulus, and its enhanced sensitivity to the action of lipases point to PManxS as a polyester of exceptional interest for those applications where biodegradability and molecular sti ff ness are priority requirements. In addition, random copolyesters (PB x Manx y S) covering a broad range of compositions have been obtained using mixtures of Manx and 1,4-butanediol in the reaction with dimethyl succinate. All PB x Manx y S were semicrystalline and displayed T g values from − 29 to +51 ° C steadily increasing with the content in Manx units. The stress − strain behavior of these copolyesters largely depended on their content in Manx and they were enzymatically degraded faster than PBS.

Mixtures of the dimethyl esters of adipic acid and 2,3:4,5-di-O-methylene-galactaric acid (Galx) were made to react in the melt with either 1,6-hexanediol or 1,12-dodecanediol to produce linear polycyclic copolyesters with aldarate unit contents varying from 10 up to 90 mole %. The copolyesters had weight–average molecular weights in the ∼35,000–45,000 g mol−1 range and a random microstructure, and were thermally stable up to nearly 300 °C. They displayed Tg in the -50 to -7 °C range with values largely increasing with the content in galactarate units. All the copolyesters were semicrystalline with Tm between 20 and 90 °C but only those made from 1,12-dodecanediol were able to crystallize from the melt at a crystallization rate that decreased as the contents in the two comonomers approached each other. Copolyesters containing minor amounts of galactarate units adopted the crystal structure characteristic of aliphatic polyesters but a new crystal polymorph was formed when the cyclic sugar units became the majority. Stress–strain parameters were sensitively affected by composition of the copolyesters with the mechanical behavior changing from flexible/ductile to stiff/brittle with the replacement of adipate units by the galactarate units.

A series of poly(ethylene terephthalate) terpolyesters containing varying amounts of both 1,4-cyclohexylenedimethylene and isosorbide units were prepared by melt phase polycondensation. These terpolymers were obtained with high molecular weights and polydispersities around 2.0–2.5. The nuclear magnetic resonance data revealed that they were all random terpolymers and that small amounts of isosorbide were lost during the polycondensation reaction. Thermal data showed that terpolymers with 90 mol% of ethylene units were crystalline, whereas the two other series containing 80 and 70 mol% were unable to crystallize from the melt. For the three series studied, it was observed that the glass transition temperature increased steadily with the content of isosorbide units, and that they had similar thermal stability.

The ring-opening polymerizations of the dilactones glycolide and the S,S- and S,R-stereoisomers of lactide were studied using quantum mechanical methods. The ring strain and the conformational distribution of these cyclic monomers and of the polymers were calculated, and the effect of the medium on the polymerization was predicted, for both bulk and solution. The polymerizability of the three monomers in the gas phase, that is, nonpolar medium, is much greater than that of d-valerolactone or 1,4-dioxan-2-one. This difference vanishes in the polar medium chloroform, which is attributed to the fact that, while all of these monomers possess polar cis-lactone bonds, the three dilactones possess small dipole moments. The data are combined to give polymerization enthalpy and free energy values. The four stereoregular lactide polymers did not differ significantly in energy. Accordingly, the ability to synthesize any one of these rests on catalyst specificity (‘‘polymer chain-end control’’). Although introduction of sterically demanding methyl groups into glycolide is expected to favor coiled conformations and decrease polymerizability, this was not found to be the case. Good agreement of calculated values with experimental data from the literature was achieved.

2,4:3,5-Di-O-methylene-D-mannitol, abbreviated as Manx, is a D-mannitol-derived compound with the secondary hydroxyl groups acetalized with formaldehyde. The bicyclic structure of Manx consists of two fused 1,3-dioxane rings, with two primary hydroxyl groups standing free for reaction. A homopolyester made of Manx and dimethyl terephthalate as well as a set of copolyesters of poly(butylene terephthalate) (PBT) in which 1,4-butanediol was replaced by Manx up to 50% were synthesized and characterized. The polyesters had Mw in the 30 000−52 000 g mol−1 range and a random microstructure and were thermally stable up to nearly 370 °C. They displayed outstanding high Tg with values from 55 to 137 °C which steadily increased with the content in Manx. Copolyesters containing up to 40% of Manx were semicrystalline and adopted the crystal structure of PBT. Their stress− strain parameters were sensitively affected by the presence of carbohydrate-based units with elongation at break decreasing but tensile strength and elastic moduli steadily increasing with the degree of replacement.

The development of polymers based on monomers from renewable feedstock, and more specifically from carbohydrates, is a steadily growing field of interest because of the properties that can generate these unique structures. They are promising materials with novel technical possibilities and improved properties, such as biocompatibility and biodegradability1,2 2,4:3,5-Di-O-methylidene-D-glucitol is a carbohydrate-based diol suitable for the preparation of linear polycondensates. This compound is readily prepared from Dgluconolactone by acetalization and subsequent reduction.4The fused bicyclic dioxolane rings provide rigidity to the molecule making it an interesting candidate for replacing aromatic rings in conventional aromatic polyesters. A series of copolyesters made of dimethylterephthalate, 1,6-hexanediol and 2,4:3,5-di-O-methylidene-D-glucitol (PHxGlxyT) with gludioxol contents ranging between 5 and 32 mol % were synthesized by melt polycondensation and characterized by NMR and FTIR spectroscopy, GPC and viscosimetry. The copolyesters had a random microstructure and number-average molecular weights ranging from 5,000 to 15,000. The influence of the content in gludioxol on the synthesis results, structure and thermal properties of the novel copolyesters was comparatively evaluated and discussed.

Outgoing