Search

In this paper, the synthesis and properties of poly(1,4-cyclohexanedimethylene-co-isosorbide terephthalate) (PCIT) with isosorbide (IS) content ranging from 16 to 61 mol% relative to the total diols amount were investigated. Amorphous polymers were successfully synthesized without isosorbide ring hydration. Glass transition temperature (Tg) linearly increased of 1.1 °C for each molar percent of isosorbide included in the polyester, meanwhile melting temperature (Tm) linearly decreased of 2.1 °C for semi-crystalline samples (up to 25 mol% of isosorbide). Molar masses of semi-crystalline samples were easily increased using high temperature solid-state polymerization (SSP) and reduced viscosity (ηred) higher than 70 mL g−1 were obtained. Semi-crystalline samples exhibit outstanding impact resistance compared with commercial high performance copolyester, whereas amorphous copolyesters exhibit acceptable mechanical properties coupled with high thermal resistance. Results confirmed the promising association between isosorbide and 1,4-cyclohexanedimethanol to reach tunable thermal and mechanical properties, depending on the targeted applications.

Fully biobased copolyesters poly(isosorbide-co-butylene 2,5-furandicarboxylate) (PISBF) were synthesized from 2,5-dimethylfuran dicarboxylate (DMFD), isosorbide (IS) and 1,4-butanediol (BDO) via transesterification and polycondensation reactions. The resulting copolymers were characterized by 1H NMR, 13C NMR, GPC, intrinsic viscosity, DSC, TGA and tensile testing, respectively. The NMR characterizations had confirmed that BDO was successfully introduced into the poly(isosorbide 2,5-furandicarboxylate) (PIF) polyester chains. Over the IS experimental composition range 20–80 % in copolymer chains, PISBF copolymers had TD, 5% values higher than 370 °C and TDM higher than 405 °C, and Tg values within the range of 55 °C and 150 °C. Introduction of BDO units into PIF chains imparted the PISBF copolyester with better mechanical performance than PIF, thus PISBF copolyesters with IS content of 20–50% were strong and toughened copolymers with Young’s modulus about 1400 MPa, tensile strength at break higher than 53 MPa, and elongation at break higher than 46%.

A series of three random copolyesters comprising biscoumarin and chalcone units as prime monomers, spaced with aliphatic alkyl chains of varying methylene units and 4,4′-oxydibenzoate, was synthesized and characterised by FTIR, NMR, TGA, DSC and XRD. The antimicrobial activity of the copolyesters was studied using Agar disc diffusion and broth dilution assay. The inhibitory effects of copolyesters were higher for Gram positive than Gram negative bacteria. All the copolyesters exhibited appreciable antimicrobial activity. In particular, copolyester 4c, poly(biscoumarin-4,4′-oxydibenzoate-3-methoxychalcone) exhibited highest inhibition zone range of 19±0.39 mm for Bacillus subtilis, 20±0.51mm for Staphylococcus aureus and 20±0.22 mm for Staphylococcus epidermidis. Bacillus subtilis was more sensitive towards copolyester 4c exhibiting a minimum inhibitory concentration of 39.05 μg/mL. Chalcone coupled biscoumarin copolyester presented good antimicrobial activities comparable with those of standard antimicrobial agents, Chloramphenicol and Amphotericin-B. Thus the incorporation of biscoumarin and chalcone units in the polymer chain exhibit very good antimicrobial activity against gram positive bacterial and fungal strains.

The interaction of (L)-lactic acid with p-tert-butylthiacalix[4]arene containing ethoxycarbonyl fragments in the 1,3-alternate conformation was studied in tetraglyme. For the first time, the lactic acid oligomer was obtained by polycondensation with the macrocycle and characterized by 1H, 13C NMR, IR spectroscopy, MALDI mass spectrometry and gel permeation chromatography. Thermal stability of the obtained copolyester of lactic acid and thiacalix[4]arene was studied by TG/DSC analysis and the effect of the macrocyclic platform on its thermal properties was shown. Copolyester obtained was thermally more stable than oligolactic acid. Self-assembly of synthesized oligomer was studied by dynamic light scattering method. It was shown that monodisperse particles (PDI = 0.13) with the size of 208 ± 4 nm are formed in CH3CN solution at 2.5 × 10−5 M concentration.

This article uses 1, 4-dithiane-2, 5-diol as a monomer to synthesize aliphatic random copolyester (PDDD).PDDD was synthesized by direct melt polycondensation method and characterized by FT-IR and 1H- NMR. The physical properties of PDDD were characterized by X-ray diffraction, differential scanning calorimetry, as well as viscosity and solubility measurements. The anticancer, antioxidant, and antimicrobial activity of PDDD were evaluated to investigate its potential biomedical applications. Generally, good results were obtained. It is evident that the copolyester exhibits favorable and tunable physical, thermal and biological properties and so is a suitable candidate for biomedical applications.

A molecular-level understanding of ion and polymer dynamics in imidazolium–poly(ethylene glycol) (PEG) copolyester ionomers having different counteranions [PF6– vs (CF3SO2)2N–], alkylene spacer len...

Shape memory polymers are of great interest for biomedical applications. However, most stimuli used to trigger shape memory processes, including heat, light, electricity, magnetism, and pH are inconvenient and maybe harmful to the body. Here, we designed and fabricated a new shape memory porous scaffold using biocompatible and readily available water as the trigger. This scaffold was based on poly(fumaricacid-co-1,7-octadiene diepoxide-co-terephthalic acid) (PFOT) synthesized via epoxide ring-opening polymerization in one step. The PFOT scaffold promoted the adhesion, spreading, proliferation and function of cardiomyoblast H9C2 cells in a manner comparable to that for the poly(lactic-co-glycolic acid) scaffold. It exhibited an excellent water-responsive shape memory effect with a fixity and recovery ratio >97% and a shape-recovery process of several minutes, suitable for surgery. In addition, the PFOT scaffold presented good in vitro biodegradation. More importantly, PFOT contains extensive free hydroxyl ...

Semicrystalline polymers generally undergo polymorphic crystal transition and lamellae structural changes during stretching deformation. Such stretch-induced multilevel microstructural evolutions a...

Biobased dihydroxy-terminated aliphatic copolyesters were synthesized from melt-polycondensation of 1,6-adipic acid with 1,6-hexanediol and 1,10-decanediol. The isodimorphic behavior of the copolyesters was explored to identify the pseudo-eutectic copolyester, which was selected as macro-initiator for ring opening polymerization of l -lactide to prepare poly( l -lactide)-b-poly(hexamethylene-co-decamethylene adipate)-b-poly( l -lactide) (PLLA-b-PHDA-b-PLLA) triblock copolymers varying PLLA block length. The blocky structure was confirmed by GPC and NMR, and the influence of PLLA block length on physical and mechanical properties was investigated. Impact testing showed that the impressive impact strength was achieved, that is, the values of PLLA10-PHDA-PLLA10 and PLLA20-PHDA-PLLA20 were largely enhanced to 357.2 J/m and 259.6 J/m, respectively, about 9–12 times greater than that of PLLA homopolymer (28.6 J/m). SEM micrographs of impact fractured surface showed that the triblock copolymers underwent a transition from brittle fracture of neat PLLA to ductile fracture, which is attributed to the introduction of flexible aliphatic polyester as middle soft building block of triblcok copolymers. This work demonstrated isodimorphic aliphatic copolyesters as midblock of PLLA-based triblock fully biobased biodegradable copolymers towards highly toughened PLLA material.

Herein, two fully renewable copolyester series, namely poly(pentylene 2,5-furandicarboxylate-co-caprolactone) (PPeCFs) and poly(hexamethylene 2,5-furandicarboxylate-co-caprolactone) (PHeCFs) were successfully synthesized with combining e-caprolactone (CL) with poly(pentylene 2,5-furandicarboxylate) (PPeF) and poly(hexamethylene 2,5-furan dicarboxylate) (PHeF) with different molar ratios. These materials, with a CL content ranging from 10 to 50 mol%, were synthesized for first time using stannous octoate as catalyst via ring opening polymerization (ROP). Their chemical structures and molar composition were evaluated by 1H NMR, 13C NMR and FTIR spectroscopies, while their thermal properties were investigated in detail using Fast Scanning Calorimetry (FSC), Differential scanning calorimetry (DSC) and Thermogravimetric analysis (TGA). The obtained results, in combination with Wide-Angle-X-ray diffractometry (WAXD), showed that copolymerization of CL with PHeF and PPeF led to semi-crystalline and partially amorphous copolyesters respectively, providing the basis for significant thermal properties enhancement with respect to the polycaprolactone (PCL) homopolymer, and therefore a much wider range of melting points (Tm) and glass transition temperatures (Tg) were obtained. TGA of the new copolymers showed excellent thermal stability, exceeding 310 °C and 360 °C for PHeCFs and PPeCFs respectively, while their decomposition mechanism was evaluated by pyrolysis-gas chromatography/mass spectroscopy (Py-GC/MS). Almost all copolyesters and mainly the ones with 40 and 50 mol% CL content showed accelerated enzymatic hydrolysis rate.

As an essential biodegradable polyester species, poly(butylene succinate) (PBS) is restricted for wider applications due to its low thermal/mechanical properties and unsatisfactory (bio)degradability. Current practice of introducing either stiff or flexible building blocks into PBS main chains remains challenging to achieve a synergistic enhancement of the thermal and (bio)degradability of this material. We herewith report a series of PBS copolyesters based on the carbohydrate-derived isosorbide (1,4:3,6-dianhydro-D-glucidol, IS) (PBIS) by utilizing its unique intrinsic characters of being rigid and hydrophilic. The target copolyesters were constructed with a broad scope of IS content (0–100 mol%) and with random microstructures. The Mn values and the intrinsic viscosities of these polyesters are in the scopes of 7300–38,700 g mol−1 and 0.33–0.82 dL g−1, respectively. The results shown in this work clearly demonstrated that the presence of IS enhances the Tg values almost linearly and simultaneously promotes (neutral, acidic) hydrolytic and enzymatic degradations (with porcine pancreas) of the copolyesters. PBIS copolyester containing 20 mol% IS displays comparable hydrolytic and enzymatic degradation rates with those of PBSA (20 mol% adipic acid), but a substantially 23 °C higher Tg value. Detailed characterization of the molecular structures, micro-sequential structures, molecular weights and polydipersities, thermal properties, hydrophilicities and (bio)degradability are provided. The (bio)degradation and degradation mechanism study of these copolyesters are reported for the first time.

To improve the mechanical properties of bio-based poly(ethylene succinate), the sugar monomer isosorbide, which is relatively easy to obtain, was used as a copolymerized third monomer to synthesize poly(ethylene-co-isosorbide succinate), a 100% biomass copolyester. The effects of isosorbide on the crystallinity and thermal properties of copolyester were studied by nuclear magnetic resonance( 1H NMR), differential scanning calorimeter( DSC), and thermogravimetric(TG). Owing to its distinct rigid bicyclic structure, isosorbide can improve the glass transition temperature of the copolyester and decrease the crystallization rate, as well as accelerate the hydrol ysis of the copolyester. Simultaneously, the introduction of isosorbide can effectively improve the antistatic properties of copolyester.

We modified poly(butylene succinate) (PBS) with sugar-based monomer isosorbide to improve the bond strength between PBS and metal interfaces and thereby alleviate the environmental problems caused by nondegradable hot-melt adhesives. We analyzed the efficiency of different catalysts in the synthesis of poly(butylene-co-isosorbide succinate) (PBIS) copolyesters. The thermal stability, thermodynamic characteristics, and melting viscosity of PBIS copolyesters were systematically evaluated by characterization. The results indicate that isosorbide can greatly improve the bond strength of the interface between PBS and the iron plate when copolyesters are used as hot-melt adhesives.

Pristine poly(butylene adipate-co-terephthalate) (PBAT) is a biodegradable aliphatic-aromatic copolyester that shows no photoluminescent features. The radio induction of photoluminescence (PL) properties in PBAT, after exposure to high doses of gamma radiation, was firstly reported in 2014. These new PL properties have great potential for applications at “in vitro” imaging of human cancer, bio-imaging devices and radiation dosimetry. In this paper, we report the radio induction of photoluminescence (PL) properties in PBAT, after exposure to low energy UV irradiation. In this investigation, films of PBAT, produced by the wire-bar coating technique, were exposed to UV radiation for periods of time ranging from 50 to 500 hours. The PL emission analysis revealed that UV irradiation performed under O2 rich air atmosphere enhances the PL output when compared to irradiations performed in the air. FTIR data confirm that the mechanism behind the UV photo-induction of PL features are similar to the mechanism suggested for gamma radio-induction PL emission. The PL intensity x Spectral Irradiance relationship and RGB color components, the green (G) and blue (B) components, can be used to perform 2D UV dosimetry. The high quantum yield emission of UV-induced PL near 500 nm observed in PBAT is a very interesting finding because it involves the development of a new cheap biodegradable photoluminescent polymer that finds application in drug delivery, bio-imaging devices and also in 2D dosimetry.

Poly(ethylene terephthalate) (PET), known for its clarity, food safety, toughness, and barrier properties, is a preferred polymer for rigid packaging applications. PET is also one of the most recycled polymers worldwide. In light of climate change, significant efforts are underway to improve the carbon footprint of PET by synthesizing it from bio-based feedstocks. Often times, specific applications demand PET to be copolymerized with other monomers. This work focuses on copolymerization of PET with a bio-based co-monomer, 2,5-furandicarboxylic acid (FDCA) to produce the copolyester (PETF). We report the multifunction of FDCA to influence the esterification reaction kinetics and the depolymerization kinetics (via alkaline hydrolysis) of the copolyester PETF. NMR spectroscopy and titrimetric studies revealed that copolymerization of PET with different levels of FDCA improved the esterification reaction kinetics by enhancing the solubility of monomers. During the alkaline hydrolysis, the presence of FDCA units in the backbone almost doubled the PET conversion and monomer yield. Based on these findings, it is demonstrated that the FDCA facilitates the esterification, as well as depolymerization of PET, and potentially enables reduction of reaction temperatures or shortened reaction times to improve the carbon footprint of the PET synthesis and depolymerization process.

In the present paper, many unsaturated polyesters has been synthesized using maleic anhydride, phthalic anhydride and succinic anhydride for esterification with new monomer [E)-1-(4-hydroxyphenyl)-3-(3-methoxy-4-hydroxyphenyl) prop-2-en-1-one]. These polyesters were polymerized by condensation reaction . Their chemical structures were characterized using FTIR, 13C-NMR and 1H NMR spectroscopy. Thermal properties have been analysed using Differential Scanning Calorimetry of synthesized polyesters All the polymers showed well thermal stability and perfect data of glass transition temperature (Tg) also the results showed polyesters and monomer were successfully synthesized by giving well spectrum improved existing an ester functional group (-COO-) in spectrums each polymer prepared also existent Chalcone functional group(-CO-CH=CH-) in spectrum of monomer.

Synthesizing different types of sequence-controlled copolyesters can enrich the diversity of copolyesters and modify their properties more precisely, but it is still a challenge to synthesize a complicated sequence-controlled copolyester using different hydroxy acids in a living polymerization manner. In this work, a highly regioselective and stereoselective catalytic system was developed to synthesize biorenewable and biodegradable copolyesters of mandelic acid and lactic acid with isotactic-alternating, heterotactic-alternating, and ABAA-type precise and complicated sequences. Because of the regular incorporation of mandelic acid into polylactide, these sequence-controlled copolymers of mandelic acid and lactic acid show higher glass-transition temperatures than polylactide and a random copolymer. A stereocomplexation interaction between two opposite enantiomeric isotactic polymer chains was also discovered in the isotactic-alternating copolymer.

In this study, an unsaturated copolyester, poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxy-10-undecenoate] (PHBU), was produced by an engineered strain of Escherichia coli, cross-linked via thiol-ene click chemistry, and analyzed for improved physical properties and biocompatibility with human mesenchymal stem cells. By cross-linking the PHBU polymer, an increase in tensile strength of greater than 200% to 26.2 MPa was observed, resulting in a material with physical properties closer to those relevant for soft tissue replacement. Results showed that this chemically cross-linked polyester did not exhibit significant cytotoxicity toward human cells after chemical modification. The chemically modifiable copolyester described here could potentially be used as a replacement for an assortment of tissues currently without viable material alternatives in the field of tissue-engineering.

[EN] ZnO compounds exert a catalytic effect on the degradation of polyesters and could affect the biodegradability of such polymers. Herein, composites of 2 wt% of ZnO particles and biodegradable commercial Ecovio polymer, a blend of poly(lactic acid) (PLA) and a copolyester, are prepared by melt extrusion process to further study the effect of the incorporation of ZnO particles on the biodegradability of this polyester under composting conditions. Different nano- and micro-sized ZnO particles are employed to investigate the effect of the size, morphology, and surface charge of ZnO on the physicochemical properties of the polymeric composite and nanocomposite by differential scanning calorimetry (DSC) and thermogravimetric analyses (TGA). The influence of such compounds on the compost disintegradability is further investigated by different techniques including, gel permeation chromatography (GPC), confocal Raman microscopy and energy dispersive x-ray spectrometer (EDX). The results demonstrate that the ZnO particles significantly accelerate the disintegration process of the Ecovio polymeric blend under a composting environment., This research was funded by the MICINN under the projects PID2019–10460 0RB-I0 0 and MAT2017–86450-C4–1-R , the Spanish National Research Council (CSIC) under the project NANOMIND CSIC 201560E068 , the Agencia Estatal de Investigación (AEI, Spain), and Fondo Europeo de Desarrollo Regional (FEDER, EU). F.R-M is indebted to MINECO for a ‘Ramon y Cajal’ contract (ref: RyC-2015–18626), which is co-financed by the European Social Fund . F.R-M also acknowledges support from a 2018 Leonardo Grant for Re- searchers and Cultural Creators (BBVA Foundation).

Big spherulite structure and high crystallinity are the two main drawbacks of poly(butylene succinate) (PBS) and hinder its application. In this work, a new type of copolyester poly(butylene succinate-co-butylene acetylenedicarboxylate) (PBSAD) is synthesized. With the incorporation of acetylenedicarboxylate (AD) units into PBS chains, the crystallization temperature and crystallinity are depressed by excluding AD units to the amorphous region. In contrast, the primary nucleation capability is significantly strengthened, without changing the crystal modification or crystallization kinetics, leading to the recovery of total crystallization rate of PBSAD under the same supercooling condition. The existence of specific interaction among AD units is found to be crucial. Although it is too weak to contribute to the melt memory effect at elevated temperature, the interaction continuously strengthens as the temperature falls down, and the heterogeneous aggregation of AD units keeps growing. When the aggregating process reaches a certain extent, it will induce the formation of a significant amount of crystal nuclei. The unveiled nucleation mechanism helps to design PBS copolymer with good performance.

The friction and wear (adhesive and abrasive wear modes) behavior of thermoplastic compounds is a multifaceted procedure, intensely pretentious by strand and special filler properties as well as operational conditions. This chapter reveals the tribological execution of small glass strand (SGF)-reinforced thermoplastic copolyester elastomer (TCE) compounds filled with both micro- (polytetrafluroethylene, silicon carbide, aluminum oxide, and molybdenum disulfide) and nanosized (aluminum oxide and perflouropolyether) special space grouts. Two-body abrasive wear (single-pass and multipass conditions) test results showed that TCE packed with PTFE space filler exhibited superior resistance to abrasion. Three-body abrasive wear data revealed that the specific wear rate (Ks) diminished with an increase in the grazing distance and increased with an upsurge in silica sand particle size. Dry sliding wear test results revealed that a TCE crossbreed compound fortified with SGF and filled with PTFE, SiC, Al2O3, and MoS2 particulates exhibited improved resistance to attrition. On the other hand, a TCE crossbreed compound filled with perfloropolyether (PFPE) nanofiller demonstrated the lowest friction coefficient in the study group. Decisively, the worn faces of the chosen wear-tested specimens were assessed using a scanning electron microscope to distinguish the involved attrition mechanisms.

A biodegradable copolyester, poly(butylene succinate-co-ε-caprolactone) (PBS_CL), was used for first time as an excipient for pharmaceutical dosage forms using direct compression and hot processing techniques (ultrasound-assisted compression (USAC) and hot melt extrusion (HME)). Robust binary systems were achieved with hot processing techniques, allowing a controlled release of the drug. With only 12% v/v of PBS_CL, controlled release forms were obtained using USAC whereas in HME over 34% v/v of excipient is necessary. Amounts over 23% v/v allowed a long-extended release for more than 72 h following diffusional kinetic. Thanks to the high melting point of theophylline and the physicochemical properties of PBS_CL selected and synthesized, the structure of the excipient inside the USAC tablets and HME filaments corresponds to a continuum medium. A percolation threshold around 23% v/v was estimated, which agrees with a continuum percolation model. The polymer shows a high excipient efficiency value using HME and USAC. A nanostructured matrix with wall thicknesses lower than 0.1 µm was obtained. This leads to a very effective coating of the drug particles by the excipient, providing a slow and reproducible release. The present study therefore supports the use of PBS_CL, for the preparation of controlled release dosage forms using hot processing techniques Ministerio de Economía y Competitividad MAT2016-77345-C3-3-P Ministerio de Ciencia, Innovación y Universidades RTI2018-095041-B-C31, RTI2018-095041-B-C33

In the field of artificial prostheses for damaged vessel replacement, polymeric scaffolds showing the right combination of mechanical performance, biocompatibility, and biodegradability are still demanded. In the present work, poly(butylene-co-triethylene trans-1,4-cyclohexanedicarboxylate), a biodegradable random aliphatic copolyester, has been synthesized and electrospun in form of aligned and random fibers properly designed for vascular applications. The obtained materials were analyzed through tensile and dynamic-mechanical tests, the latter performed under conditions simulating the mechanical contraction of vascular tissue. Furthermore, the in vitro biological characterization, in terms of hemocompatibility and cytocompatibility in static and dynamic conditions, was also carried out. The mechanical properties of the investigated scaffolds fit within the range of physiological properties for medium- and small-caliber blood vessels, and the aligned scaffolds displayed a strain-stiffening behavior typical of the blood vessels. Furthermore, all the produced scaffolds showed constant storage and loss moduli in the investigated timeframe (24 h), demonstrating the stability of the scaffolds under the applied conditions of mechanical deformation. The biological characterization highlighted that the mats showed high hemocompatibility and low probability of thrombus formation, finally, the cytocompatibility tests demonstrated that cyclic stretch of electrospun fibers increased endothelial cell activity and proliferation, in particular on aligned scaffolds.

Tribology (which is the study of friction, wear, and lubrication) has emerged as one of the fields that contribute to sustainable development through environmentally friendly solutions. These solutions are aimed to reduce energy consumption by lowering power losses during sliding applications. Power losses at sliding interfaces can be diminished by reducing the abrasive and adhesive nature of hard metal asperity interactions. One way to reduce friction losses is using high-performance polymer coatings (HPPCs) as interacting (sliding) surfaces (tribopairs). It has been shown that HPPCs based on polyether ether ketone (PEEK), polytet- rafluoroethylene (PTFE), and aromatic thermosetting copolyester (ATSP) blended with solid lubricants can withstand high bearing loads and provide self-lubrication. High-Performance Polymer (HPP) Blends. Thermal Properties of Polymer Coatings. Micro-/Nanoindentation and Micro-/Nanoscratch Techniques. Micromechanical Properties of HPPCs. Correlation of Micromechanical Properties with Microstructure Primera edición

Considering the rising demand to diminish energy consumption and CO2 emissions, the biobased segmented block copolymer, poly(butylene succinate-co-dilinoleic succinate) (PBS-DLS) with 70:30 (wt %) ratio of hard to soft segments was obtain using Candida antarctica lipase B (CAL-B) as a biocatalyst. Throughout two-step synthesis in diphenyl ether, biobased diethyl succinate was polymerized with renewable 1,4–butanediol and dimer linoleic diol to obtain “green” copolyester as a sustainable alternative to petroleum-based materials. Proton nuclear magnetic resonance (1H NMR) analysis confirmed that, using enzyme as a catalyst, we were able to produce multiblock copolymer and gel permeation chromatography (GPC) measurements revealed number-averaged molecular mass to be 25,000 g/mol. Additionally, differential scanning calorimetry (DSC) analysis revealed low-temperature glass transition (Tg) of soft segments and high melting point (Tm) of hard segments which indicate on two-phase morphology. Furthermore, cytotoxicity test using L929 murine fibroblasts was conducted on extracts of obtained PBS-DLS copolymer, indicating excellent biocompatibility in vitro.

This research synthesizes novel copolyester (PCITN) containing biobased isosorbide, 1,4-cyclohexandimethanol, terephthalic acid, and 2,6-naphthalene dicarboxylic acid and characterize its properties. The PCITN copolyester was extruded into film, and its performance properties including: tensile strength, Young&rsquo, s modulus, thermal, dimensional stability, barrier (water barrier), and optical (birefringence and transmittance) were analyzed after uniaxial stretching. The films have higher Tg, Tm, dimensional stability, and mechanical properties than other polyester-type polymers, and these performance properties are significantly increased with increasing stretching. This is due to the increased orientation of molecular chains inside the films, which was confirmed by differential scanning calorimetry (DSC), X-ray diffraction (XRD), and birefringence results. Good water barrier (0.54%) and lower birefringence (△n: 0.09) of PCITN film compared to poly(ethylene terephthalate) (PET), poly(ethylene 2,6-naphthalate) (PEN), and polyimide (PI) films, used as conventional substrate materials for optical devices, make it an ideal candidate as performance material for next-generation flexible devices.

In this study, poly(butylene sebacate-co-terephthalate) (PBSeT) was successfully synthesized using various ratios of sebacic acid (Se) and dimethyl terephthalate (DMT). The synthesized PBSeT showed a high molecular weight (Mw, 88,700&ndash, 154,900 g/mol) and good elastomeric properties. In particular, the PBSeT64 (6:4 sebacic acid/dimethyl terephthalate mole ratio) sample showed an elongation at break value of over 1600%. However, further increasing the DMT content decreased the elongation properties but increased the tensile strength due to the inherent strength of the aromatic unit. The melting point and crystallization temperature were difficult to observe in PBSeT64, indicating that an amorphous copolyester was formed at this mole ratio. Interestingly, wide angle X-ray diffraction (WAXD) curves was shown in the cases of PBSeT46 and PBSeT64, neither the crystal peaks of PBSe nor those of poly(butylene terephthalate) (PBT) are observed, that is, PBSeT64 showed an amorphous form with low crystallinity. The Fourier-transform infrared (FT-IR) spectrum showed C&ndash, H peaks at around 2900 cm&minus, 1 that reduced as the DMT ratio was increased. Nuclear magnetic resonance (NMR) showed well-resolved peaks split by coupling with the sebacate and DMT moieties. These results highlight that elastomeric PBSeT with high molecular weight could be synthesized by applying DMT monomer and showed promising mechanical properties.

Structural, thermal and mechanical properties of the compostable composites comprising a biodegradable aliphatic-aromatic copolyester (namely, the poly(butylene adipate-co-terephthalate; PBAT), and microcrystalline cellulose (MCC) derived from agricultural waste, the wheat stalk, were investigated. Purely physical interaction between the components was found to be responsible to get the MCC phase quite uniformly embedded in the PBAT matrix, the latter being the dominating component of the composites surface. There were two distinct thermally activated degradation regimes characterized by separate activation processes corresponding to the decomposition of the MCC and the PBAT phases, respectively. The physically bound and rather weak but large PBAT-MCC interfacial areas provoked more rapid thermal degradation of the composites compared to the pure components. While the PBAT acted as a highly ductile material upon tensile loading, the composites maintained high ductility only up to 20% by weight of the MCC. The drastic reduction in the ductility for higher filler loading was attributed to the possible void formation at the interfacial region followed by crack initiation and propagation leading eventually to the premature specimen fracture. The composite materials thus fabricated were hence found to suit for low-load bearing applications.

Bio-based unsaturated poly(butylene adipate-co-butylene itaconate) (PBABI) aliphatic copolyesters were synthesized with pentaerythritol (PE) as a modifier, observing the melting point, crystallization, and glass transition temperatures were decreased from 59.5 to 19.5 °C and 28.2 to −9.1 °C as an increase of itaconate concentration, and Tg ranged from −54.6 to −48.1 °C. PBABI copolyesters tend to the amorphous state by the existence of the BI unit above 40 mol%. The yield strength, elongation, and Young’s modulus at different BA/BI ratios were valued in a range of 13.2–13.8 MPa, 575.2–838.5%, and 65.1–83.8 MPa, respectively. Shear-thinning behavior was obtained in all BA/BI ratios of PBABI copolyesters around an angular frequency range of 20–30 rad s−1. Furthermore, the thermal and mechanical properties of PBABI copolyesters can be well regulated via controlling the itaconic acid contents and adding the modifier. PBABI copolyesters can be coated on a 3D air mesh polyester fabric to reinforce the mechanical property for replacing traditional plaster applications.

In recent years, a significant progress has been made in the development and study of nanoparticles aimed at biomedical applications. Polymer systems are believed to be an interesting perspective in this direction, because they can be designed as multifunctional systems for drug delivery and release, as well as they can provide information about their location using fluorescence spectroscopy methods. The nanoparticles get directly into the bloodstream through intravenous injections. In most cases, the first molecules which they interact are proteins, which are one of the main constituents of the human body and the driving force of most biological processes. Therefore, understanding the interaction between nanoparticles and proteins is important for the safe and effective use of nanoparticles. In this regard, changes in the properties of nanoparticles after interaction with albumin have been analyzed and it has been shown that albumin, depending on the structure of the amphiphilic copolyester, either acts as an additional stabilizer of nanoparticles dispersed phase or leads to partial aggregation. At the same time, the albumin layer slightly affects the characteristics of biodistribution and the hydrolytic properties of the obtained amphiphilic copolyesters with fluorescent moieties.

The hydrophilic copolyester polyethylene terephthalate (PET) (ENCDP-X) was successfully synthesized by chemical modification consisting of copolymerization and blending and the comonomers, including sodium isophthalate-5-sulfonate (SIPE), polyethylene glycol (PEG), 2,2-dimethyl-1,3-propanediol (NPG) and matting agent TiO2 with different content. Moreover, the structural characterization of sequential structure, crystallization and thermal properties were studied. The results showed that the comonomers were successfully embedded in the copolyester, the actual molar ratio in the copolyester was consistent with the relative feed ratio and the degree of randomness was calculated to be 0.99, showing that the random copolymers synthesized during the melt polycondensation process and the chemical structure was roughly consistent with the expected molecular chain sequence structure. The thermal parameters of the modified copolyester, containing the glass transition temperature (Tg), melting point (Tm), crystallinity (Xc) and thermal degradation temperature, were decreased, and the cold crystallization temperature (Tc) was increased. In addition, with the increasing of the TiO2 content, it improves the thermal performance of the copolyester and it is beneficial to processing and application. The above conclusion is further verified by non-isothermal kinetic analysis. In addition, the copolyester exhibited the better hydrophilicity than pure PET.

© 2020 by the authors., In the present study, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) [P(3HB-co-3HHx)] was reinforced with hydroxyapatite nanoparticles (nHA) to produce novel nanocomposites for potential uses in bone reconstruction. Contents of nHA in the 2.5–20 wt % range were incorporated into P(3HB-co-3HHx) by melt compounding and the resulting pellets were shaped into parts by injection molding. The addition of nHA improved the mechanical strength and the thermomechanical resistance of the microbial copolyester parts. In particular, the addition of 20 wt % of nHA increased the tensile (Et) and flexural (Ef) moduli by approximately 64% and 61%, respectively. At the highest contents, however, the nanoparticles tended to agglomerate, and the ductility, toughness, and thermal stability of the parts also declined. The P(3HB-co-3HHx) parts filled with nHA contents of up to 10 wt % matched more closely the mechanical properties of the native bone in terms of strength and ductility when compared with metal alloys and other biopolymers used in bone tissue engineering. This fact, in combination with their biocompatibility, enables the development of nanocomposite parts to be applied as low-stress implantable devices that can promote bone reconstruction and be reabsorbed into the human body., This research work was funded by the Spanish Ministry of Science and Innovation (MICI) project numbers RTI2018-097249-B-C21 and MAT2017-84909-C2-2-R and the POLISABIO program with grant number 2019-A02.

Unsaturated poly (butylene adipate-co-butylene itaconate) (PBABI) copolyesters were synthesized through melt polymerization composed of 1,4-butanediol (BDO), adipic acid (AA), itaconic acid (IA) and 1,2,4,5-benzenetetracarboxylic acid (BTCA) as a cross-linking modifier. The melting point, crystallization and glass transition temperature of the PBABI copolyesters were detected around 29.8&ndash, 49 &deg, C, 7.2&ndash, 29 &deg, C and &minus, 51.1 and &minus, 58.1 &deg, C, respectively. Young&rsquo, s modulus can be modified via partial cross-linking by BTCA in the presence of IA, ranging between 32.19&ndash, 168.45 MPa. Non-isothermal crystallization kinetics were carried out to explore the crystallization behavior, revealing the highest crystallization rate was placed in the BA/BI = 90/10 at a given molecular weight. Furthermore, the thermal, mechanical properties, and crystallization rate of PBABI copolyesters can be tuned through the adjustment of BTCA and IA concentrations.

Aromatic copolyesters, derived from bio-based nipagin and eugenol, were synthesized with renewable 1,6-hexandiol as the spacer. Number-average, weight-average molecular weights (Mn, Mw), and polydispersity (D) values were determined by size exclusion chromatography (SEC). Chemical structures were confirmed by 1H NMR and 13C NMR spectroscopies. Chemical microstructure analysis suggested that the nipagin and eugenol-derived units were inserted into polymer chains in an arbitrary manner. Due to the short chain of 1,6-hexanediol, the splitting of magnetically different methylene carbons, adjacent to the alcohol-oxygens, proved to be more sensitive towards sequence distributions, at the dyed level, than those from 1,10-decanediol. Thermal gravimetric analysis (TGA) demonstrated that these polyester materials have excellent thermal stability (&gt, 360 &deg, C), regardless of the content of eugenol-derived composition incorporated. Differential scanning calorimetric (DSC) and wide-angle X-ray diffraction (WXRD) experiments revealed the semicrystalline nature for this kind of copolyesters. The crystallinities gradually decreased with the increase of eugenol-derived composition. Thermal and crystalline properties were well discussed from the microscopic perspective. The point of this work lies in establishing guidance for future design and modification of high-performance polymer materials from the microscopic perspective.

In this work, a bio-based copolyester with good mechanical properties was synthesized and characterized in terms of structure, main properties and biodegradability Determining the chemical structure of such materials is important to understand their behavior and properties. Performing an extraction of insoluble cross-linked polymer using different solvents allowed us to analyze how the polymer behaves when subjected to different chemical environments, and to obtain soluble samples suitable for more in-depth analysis. Chemical structure of poly (xylitol sebacate-co-butylene sebacate) was determined by a 1H NMR and FTIR analysis of both prepolymer gel sample and samples obtained by extraction of cross-linked polymer using different solvents. Block structure of the copolymer was confirmed by both NMR and DSC. Gel fraction, swelling value, water contact angle, and mechanical properties were also analyzed. Biodegradability of this material was confirmed by performing enzymatic and hydrolytic degradation. Synthesizing sugar-alcohol based copolyester using three monomers leads to obtaining a material with interesting chemical structure and desirable mechanical properties comparable to conventional elastomers.

Poly(ethylene-co-isosorbide terephthalate) (PEIT) copolyesters could be used in various applications depending on their ability to crystallize. Moreover, the possibility to carry out solid-state post-condensation (SSP) is conditioned by its ability to sufficiently crystallize. The present study, thus, gives a systematic investigation of isothermal crystallization of these statistical copolyesters with isosorbide contents ranging from 4.8 to 20.8 mol.%. For each copolyester composition, the lowest isothermal half crystallization times and the highest Avrami constant (K) were obtained around 170 &deg, C. Over the range of composition that was studied, both melting points and melting enthalpies decreased with increasing amounts of isosorbide (from 250 to 207 &deg, C and from 55 to 28 J/g, respectively). On the contrary, half crystallization time displayed an exponential increase when increasing isosorbide contents in the studied range. Finally, structural and thermal analysis of PIT homopolyester are reported for the first time, showing that only ET moieties crystallized when PEIT was subjected to isothermal crystallization at 170 &deg, C.

Dye-sensitized photooxygenation reaction of bio-based double bond-containing substrates is proposed as sustainable functionalization of terpenes and terpenoids to transform them into polyoxygenated compounds to be employed for the synthesis of new bio-based polyesters. As proof of concept, citronellol 1 has been regioselectively converted into diol 4 using singlet oxygen (O-1(2)), a traceless reagent that can be generated from air, visible light and zeolite supported-photosensitizer (Thionine-NaY). With our synthetic approach, diol 4 has been obtained in two-steps, with good regioselectivity, using green reagents such as light and air, and finally a solvent-free oxidation step. From this compound, a citronellol-based copolyester of poly(butylene succinate) (PBS) has been synthesized and fully characterized. The results obtained evidence that the proposed copolymerization of PBS with the citronellol-based building blocks allows to obtain a more flexible and functionalizable material, by exploiting a largely available natural molecule modified through a green synthetic path.

Random disposal and accumulation of commodity plastics in the open environment after their end use is an issue that has triggered a lot of concerns both in public and academic debates owing to their seemingly high contribution toward the environmental pollution and potential impacts on biota and human health. Thus, finding the greener solution to this problem has got immense socio-economic and ecological significance. As a result, there is an increasing trend of using biodegradable or compostable polymeric materials. It has been demonstrated that the incorporation of plants-based reinforcing fillers into biodegradable polymers to construct composite materials have proved benefits in various applications. A great deal of research has been performed in order to develop novel sustainable polymeric materials having tailored physical properties over a wide range. As a consequence, by using bio-based fillers, new composite materials have been developed and commercialized. In this chapter, initially, the attention will be made on the review of different methods of extracting microcrystalline (MCC) and nanocrystalline (NCC) celluloses from different agro-based wastes using a series of thermo-mechanical and chemical processing routes. After a quick review on the structure-properties correlation of the micro- and nanocomposites of copolyesters, we shed light on biodegradable green composites with special emphasis on their morphological studies and correlations to deformation and degradation behavior. On the ground of the results obtained from our laboratory complemented by literature works, the structure-property correlations of copolyester-based composites have been discussed. Finally, the chapter concludes highlighting the new trends, major challenges, and opportunities relevant to the related research field.

In this work, we study for the first time, the isothermal crystallization behavior of isodimorphic random poly(butylene succinate)-ran-poly(&epsilon, caprolactone) copolyesters, PBS-ran-PCL, previously synthesized by us. We perform nucleation and spherulitic growth kinetics by polarized light optical microscopy (PLOM) and overall isothermal crystallization kinetics by differential scanning calorimetry (DSC). Selected samples were also studied by real-time wide angle X-ray diffraction (WAXS). Under isothermal conditions, only the PBS-rich phase or the PCL-rich phase could crystallize as long as the composition was away from the pseudo-eutectic point. In comparison with the parent homopolymers, as comonomer content increased, both PBS-rich and PCL-rich phases nucleated much faster, but their spherulitic growth rates were much slower. Therefore, the overall crystallization kinetics was a strong function of composition and supercooling. The only copolymer with the eutectic composition exhibited a remarkable behavior. By tuning the crystallization temperature, this copolyester could form either a single crystalline phase or both phases, with remarkably different thermal properties.

In this paper, we study for the first time the effect of hard confinement on the isodimorphic crystallization of random copolyesters. A series of poly(butylene succinate-ran-caprolactone) samples encompassing the entire composition range were successfully infiltrated into nanoporous alumina templates (anodic aluminum oxide (AAO)) with a fixed diameter of 100 nm. The samples were characterized using scanning electron microscopy (SEM), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and grazing-incidence wide-angle X-ray scattering (GIWAXS). FTIR proved that poly(butylene succinate) (PBS)-rich nanofibers showed interactions between the copolyester chains and the walls of the AAO templates; however, the poly(ε-caprolactone) (PCL)-rich nanofibers did not show any interaction with the AAO walls. All infiltrated samples experienced a very large decrease in crystallization temperature, as expected, since the level of confinement is large enough to suppress heterogeneous nucleation. In spite of this, all copolymers were able to crystallize, regardless of composition. Additionally, when Tc or Tm is plotted versus copolymer composition, a clear pseudoeutectic point is observed. These results indicate that the isodimorphic behavior of the copolyesters is maintained under hard confinement. Infiltrated PCL undergoes homogeneous nucleation (inside the nanopore volume) as expected by the lack of interaction with the AAO walls. On the other hand, PBS exhibited a surface nucleation mechanism triggered by the interactions with the AAO walls. In the case of random copolymers, all PCL-rich copolymers nucleated homogeneously. However, in the case of PBS-rich copolymers, the nucleation gradually changed from surface-induced nucleation for neat PBS to homogeneous nucleation as the PCL concentration in the copolymers increased and the interactions of PBS chains with the AAO walls are diluted. The confinement under 100 nm nanopores did not change the orientation of the PBS or PCL phase crystals, which kept their chain direction perpendicular to the pore axis, as demonstrated by GIWAXS., The authors acknowledge the support of the National Key R&D Program of China (2017YFE0117800) and the National Natural Science Foundation of China (21873109, 51820105005). The authors would also like to acknowledge financial support provided by the BIODEST project; this project has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement no. 778092. The UPV/EHU and ICTP-CSIC Institutions acknowledge financial support from the Spanish Ministry of Science, Innovation, and Universities (MAT2017-83014-C2-2-P and MAT2017-83014-C2-1-P). M.S. thankfully acknowledges her Ph.D. fellowship by POLYMAT Basque Center for Macromolecular Design and Engineering. The authors would like to thank Dr. Antxon Martinez de Ilarduya and Prof. Sebastian Muñoz for their help in the synthesis of copolyesters at UPC, Spain. J.M. gratefully acknowledges support from the Provincial Council of Gipuzkoa under the program Fellow Gipuzkoa and “Fomento San Sebastián” in the framework program “Retorno del Talento Local” Donostia up! 2016.

A biodegradable bio-based copolyester, poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) with the 3-hydroxyhexanoate composition of 5.4 mol%, was used in this study. A liquid isothermal bath (LIB) was installed into the high-speed melt spinning process to improving the mechanical properties of the PHBH fibers. When the spin-line passes through the LIB, temperature of the molten polymer can be controlled to the liquid temperature whereas the frictional stress of about 100 times higher than that in the air can be applied to the spin-line in the liquid. In the process with the LIB, the liquid temperature, the depth of the liquid bath and the take-up velocity were varied. Tensile strength of the high-speed spun PHBH fibers without LIB was only around 100 MPa. On the other hand, tensile strength of the fibers prepared with the LIB increased with the reduction of liquid temperature and with the increase of take-up velocity. At the take-up velocity of 1 km/min, liquid temperature of 40 °C and liquid depth of 20 cm, the fibers with the tensile strength of 176 MPa could be obtained. The WAXD measurement revealed that along with the highly oriented β-form crystals, co-existence of the β-form crystals was confirmed for the PHBH fibers of high strength prepared using the LIB.