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Carbon/Phenolic Composites (CPCs) are essential to manufacture many portions of the nozzle assembly of Solid Rocket Motors (SRMs) which are essential both to preserve the independent access to space as well as for the homeland security. In our research, a feasible approach aimed at preliminary retrieving the in-plane and out-plane thermal diffusivity of CPCs through the Oxy-Acetylene Torch (OAT) tests was validated. The proposed approach showed to be effective and able to bypass some limitations of common protocols, especially in terms of capability to determine the thermal diffusivity of CPCs at high heating rates. A comprehensive work of comparison of the obtained data with state-of-the-art CPCs such as MX-4926 and FM-5014 has also been carried out, evidencing the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

In this work, the use of nano-boron carbide as a nanomodifier of phenolic matrix was envisioned. Particularly, nano-boron carbide/phenolic-based nanocomposites were produced and investigated. The obtained nanostructured matrices were also used to produce carbon fiber-based bulk molding compounds (BMC). The thermal stability of nanocomposites and BMCs was investigated by thermogravimetric analysis both in nitrogen and in air atmospheres. The good dispersion and distribution of the nanosized particles in the matrix was confirmed by transmission electron microscopy while the post-burning appearance of the BMCs was investigated by visual inspection and scanning electron microscopy. The experimental data highlighted the remarkable effects of nano-boron carbide on the thermal stability and oxidation resistance of the carbon fiber-based BMCs. Moreover, the boron oxide produced by the conversion of boron carbide allowed a substantial improvement of the dimensional stability of the BMC which also exhibited considerable residual structural integrity after burning. POLYM. COMPOS., 38:1819-1827, 2017. © 2015 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

• A feasible approach able to assess the heat capacity as a function of temperature (up to 550 °C) of carbon/phenolic composites has been validated. • Common DSC and TGA equipments were used. • The protocol was studied using both bulk or powdered samples. • The protocol was validated on ad hoc made CPCs and compared to state-of-the-art aerospace-qualified materials such as the MX-4926. • The possibility to evaluate the heat of decomposition of high char yield was also discussed. Carbon/Phenolic Composites (CPCs) are among most important Thermal Protection System (TPS) materials. In addition to the challenges related to the manufacturing issues - partially covered in this paper - the possibility to properly characterize the thermo-physical and thermo-mechanical properties of CPCs is extremely important. These data are not only used to size the TPS of a space vehicle or the nozzle components of a Solid Rocket Motor (SRM) but they are also essential to model the response of a CPC in a given hyperthermal environment. However, most of the papers reporting the thermo-physical and thermo-mechanical properties of CPCs are based on very old testing facilities and, in many cases, special equipments have been developed ad-hoc. As a result, the aim of this paper was to identify a feasible approach able to assess the heat capacity as a function of temperature (up to 550 °C) of CPCs through the use of common DSC and TGA analysis, taking into account all the degradation steps of the polymeric matrix undergoing charring. The possibility to evaluate the heat of decomposition of high char yield matrices through the introduced protocols was also discussed. [Display omitted] [ABSTRACT FROM AUTHOR]

The development of bio-based materials is of great importance in the present environmental circumstances; hence, research has greatly advanced in the valorization of lignin from lignocellulosic wastes. Lignin is a natural polymer with a crosslinked structure, valuable antiradical activity, unique thermal- and UV-absorption properties, and biodegradability, which justify its use in several prospective and useful application sectors. The active functionalities of lignin promote its use as a valuable material to be adopted in the composite and nanocomposites arenas, being useful and suitable for consideration both for the synthesis of matrices and as a nanofiller. The aim of this review is to summarize, after a brief introduction on the need for alternative green solutions to petroleum-based plastics, the synthesis methods for bio-based and/or biodegradable thermoplastic and thermosetting nanocomposites, along with the application of lignin nanoparticles in all green polymeric matrices, thus generating responsiveness towards the sustainable use of this valuable product in the environment. [ABSTRACT FROM AUTHOR]

Using biomass to develop and obtain environmentally friendly and industrially applicable biomaterials is increasingly attracting global interest. Herein, cellulose nanocrystals (CNCs) and lignin nanoparticles (LNPs) were extracted from Lemna minor L., a freshwater free-floating aquatic species commonly called duckweed. To obtain CNCs and LNPs, two different procedures and biomass treatment processes based on bleaching or on the use of an ionic liquid composed of triethylammonium and sulfuric acid ([TEA][HSO4]), followed by acid hydrolysis, were carried out. Then, the effects of these treatments in terms of the thermal, morphological, and chemical properties of the CNCs and LNPs were assessed. The resulting nanostructured materials were characterized by using Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) spectroscopy, thermo-gravimetric analysis (TGA), and scanning electron microscopy (SEM). The results showed that the two methodologies applied resulted in both CNCs and LNPs. However, the bleaching-based treatment produced CNCs with a rod-like shape, length of 100–300 nm and width in the range of 10–30 nm, and higher purity than those obtained with ILs that were spherical in shape. In contrast, regarding lignin, IL made it possible to obtain spherical nanoparticles, as in the case of the other treatment, but they were characterized by higher purity and thermal stability. In conclusion, this research highlights the possibility of obtaining nanostructured biopolymers from an invasive aquatic species that is largely available in nature and how it is possible, by modifying experimental procedures, to obtain nanomaterials with different morphological, purity, and thermal resistance characteristics. [ABSTRACT FROM AUTHOR]

The main objective of this research activity was to design and realize active films with tunable food functional properties. In detail, caffeic acid (CA), a polyphenol with high antioxidant effect, was used as active ingredient in poly (vinyl alcohol-co-ethylene) (EVOH) films at 5 wt.% and 15 wt.% and successfully realized by means of the solvent casting process. Optical, morphological, thermal and mechanical studies were considered to define the effect of the presence of the CA component on the structural properties of the matrix. In addition, moisture content and antioxidant activity were evaluated, to have clear information on the CA effect in terms of functional characteristics of realized food packaging systems. Results from tensile tests showed increased values for strength and deformation at break in EVOH_CA based films. Results from colorimetric and transparency analysis underlined that the presence of caffeic acid in EVOH copolymer induces some alterations, whereas the addition of the active ingredient determined a positive radical scavenging activity of the formulations, confirming the possibility of practically using these polymeric systems in the food packaging sector. [ABSTRACT FROM AUTHOR]

We propose a new methodology for long-term biopotential recording based on an MEMS multisensor integrated platform featuring a commercial electrostatic charge-transfer sensor. This family of sensors was originally intended for presence tracking in the automotive industry, so the existing setup was engineered for the acquisition of electrocardiograms, electroencephalograms, electrooculograms, and electromyography, designing a dedicated front-end and writing proper firmware for the specific application. Systematic tests on controls and nocturnal acquisitions from patients in a domestic environment will be discussed in detail. The excellent results indicate that this technology can provide a low-power, unexplored solution to biopotential acquisition. The technological breakthrough is in that it enables adding this type of functionality to existing MEMS boards at near-zero additional power consumption. For these reasons, it opens up additional possibilities for wearable sensors and strengthens the role of MEMS technology in medical wearables for the long-term synchronous acquisition of a wide range of signals. [ABSTRACT FROM AUTHOR]

In the present review, the possibilities for blending of commodities and bio-based and/or biodegradable polymers for packaging purposes has been considered, limiting the analysis to this class of materials without considering blends where both components have a bio-based composition or origin. The production of blends with synthetic polymeric materials is among the strategies to modulate the main characteristics of biodegradable polymeric materials, altering disintegrability rates and decreasing the final cost of different products. Special emphasis has been given to blends functional behavior in the frame of packaging application (compostability, gas/water/light barrier properties, migration, antioxidant performance). In addition, to better analyze the presence of nanosized ingredients on the overall behavior of a nanocomposite system composed of synthetic polymers, combined with biodegradable and/or bio-based plastics, the nature and effect of the inclusion of bio-based nanofillers has been investigated. [ABSTRACT FROM AUTHOR]

• Experimental investigation of high temperature thermal storage concrete materials. • Phase change materials (solar salt) added to concrete to increase energy density. • Thermal and mechanical characterization of concrete and 2 wt% phase change material. • Thermal and mechanical properties increase with no phase change materials leakage. • Better behaviour of phase change material/diatomite even after 250 °C. Thermal energy storage is one of the most appropriate technologies to correct the gap between the energy generation and supply and to address energy challenges. Concrete is generally the preferred "solid" heat storage material because its low cost and good thermal conductivity. The major disadvantage is its low heat stored density involving the use of large amounts of concrete. Latent heat storage materials (or phase change materials), have received more attention due to much higher heat storage density and extremely smaller temperature variation during the thermal energy charge/discharge process. These materials can be incorporated in the concrete by using different methods. When the phase change material is encapsulated or added in a shape-stabilized new material, as diatomite, the phase change material leakage is avoided. Thermal and mechanical characteristics of a new heat storage material, composed by concrete with the addition of 2% Solar Salts by weight (as phase change material) in powder or capsules form, were analyzed. The results showed an increase of the main thermal (volumetric heat capacity and conductivity) and mechanical properties while phase change material leakage was not observed. In particular, the phase change material/diatomite capsules provide a better behavior even after 250 °C. [ABSTRACT FROM AUTHOR]

Here, we present novel biocompatible poly(butylene trans-1,4-cyclohexanedicarboxylate) (PBCE)-based random copolymer nanostructured scaffolds with tailored stiffness and hydrophilicity. The introduction of a butylene diglycolate (BDG) co-unit, containing ether oxygen atoms, along the PBCE chain remarkably improved the hydrophilicity and chain flexibility. The copolymer containing 50 mol% BDG co-units (BDG50) and the parent homopolymer (PBCE) were synthesized and processed as electrospun scaffolds and compression-molded films, added for the sake of comparison. We performed thermal, wettability, and stress–strain measures on the PBCE-derived scaffolds and films. We also conducted biocompatibility studies by evaluating the adhesion and proliferation of multipotent mesenchymal/stromal cells (hBM-MSCs) on each polymeric film and scaffold. We demonstrated that solid-state properties can be tailored by altering sample morphology besides chemical structure. Thus, scaffolds were characterized by a higher hydrophobicity and a lower elastic modulus than the corresponding films. The three-dimensional nanostructure conferred a higher adsorption protein capability to the scaffolds compared to their film counterparts. Finally, the PBCE and BDG50 scaffolds were suitable for the long-term culture of hBM-MSCs. Collectively, the PBCE homopolymer and copolymer are good candidates for tissue engineering applications. [ABSTRACT FROM AUTHOR]

The present work reports on the development of environmentally friendly, completely biodegradable wood plastic composites based on polylactide (PLA) and tangerine peel flour (TPF), plasticized by α-terpinyl acetate (TA). The TPF varied in the 10--30 wt% while the PLA to TA (wt%/wt%) was set to 4 (i.e., 25 wt% TA plasticizer was added with regard to the PLA wt%). The developed composites were processed by extrusion and injection molding. The composites presented excellent elongation at break, achieving values of 300% for the PLA+TA sample. Elongation at break values of 200% for the PLA composite with 10 wt% TPF and plasticized with TA were obtained. Those results were confirmed by the appearance of filament-like structures observed in field emission scanning electron microscopy images. Differential scanning calorimetry and dynamic mechanical thermal analysis revealed a remarkable decrease in the glass transition temperature of PLA as a result of the plasticizing effect of TA. Glass transition was reduced from 63°C down to 41°C approximately. This implied an increase in the ductility of the material. The samples with TPF exhibited a dark brown color, making them perfect for wood plastic composite applications. Water contact angle results show that TA and TPF change the wetting properties of the obtained composites. A general decrease in the water contact angle was observed with the addition of TPF and TA. Finally, disintegration tests proved that the developed composites are fully biodegradable. All the samples except for neat PLA achieved 100% disintegration in controlled compost soil conditions after 5 weeks, while neat PLA reached complete disintegration in 6 weeks. [ABSTRACT FROM AUTHOR]

Solid Rocket Motors (SRMs) are used to launch satellites and other civilian or military payloads in orbit. Due to their low density and outstanding insulation capability, EPDM/aramid fibers ablatives represent the state of the art of Elastomeric Heat Shielding Materials (EHSMs) SRMs. However, this class of polymeric ablatives tend to exhibit a limited ablation resistance induced by thermo-oxidation and mechanical erosion due to the propellant combustion byproducts. In order to increase the thermo-oxidation resistance, char retention, and insulation index, boron based fillers can be considered in the material formulation of the SRM insulation liner. In this work we systematically studied the effect of different boron containing fillers embedded in EPDM based EHSMs. The heat capacity, thermal stability, mechanical properties, ablation resistance, pre- and post-oxy-acetylene torch testing morphology of these materials were analyzed evidencing the clear benefits of these fillers. [ABSTRACT FROM AUTHOR]

This work reports on the development of polylactide (PLA)/mango kernel seed flour (MKSF) composites combined with tributyrin (TBN) and triacetin (TCN) as plasticizers. Thus, wood plastic composites (WPC) are obtained by extrusion and injection-molding processes. The solubility, mechanical, morphological, thermal, colorimetric, water absorbance, flowability, and disintegrability properties are evaluated. The ductility of the PLA+MKSF composite is improved by the plasticizing effect of TBN and TCN (10 phr (parts per hundred resin) each). Elongation at break is increased from 4.4 up to 9.5 and 8.3%, respectively. The theoretical solubility analysis supports the good miscibility between PLA with TBN and TCN (relative energy difference (RED) values of 0.86 and 0.73, respectively) deduced from the mechanical performance. Field emission scanning electron microscopy (FESEM) images also corroborate the mechanical findings, where a decrease in the presence of voids in the PLA matrix suggests certain compatibility between MKSF and TBN, and TCN. Differential scanning calorimetry (DSC) and dynamic-mechanical-thermal analysis (DMTA) results show that the plasticizers decrease the glass transition temperature and the melting temperature of PLA, thus improving its ductility. Thermogravimetric analysis (TGA) results indicate that the thermal stability of the composite is slightly decreased due to the relatively high volatility of the plasticizers, while MKSF does not affect this matter. The composites exhibit excellent biodegradability, presenting more than 90% of disintegration in compost soil conditions in 12 weeks. Finally, MKSF provided the composites with a wood-like dark brown color and with high water absorbance. [ABSTRACT FROM AUTHOR]

Ablative materials are at the base of entire aerospace industry; these sacrificial materials are used to manage the heat shielding of propulsion devices (such as liquid and Solid Rocket Motors (SRMs)) or to protect vehicles and probes during the hypersonic flight through a planetary atmosphere. Accordingly they are also known as Thermal Protection System (TPS) materials. Some non-polymeric materials have been successfully used as ablatives; however, due to their versatility, Polymeric Ablatives (PAs) represent the widest family of sacrificial TPS materials. In fact, when compared to non-polymeric ablatives such as high melting point metals, inorganic polymers (or metal oxides or carbides), PAs have some intrinsic advantages such as: tunable density, lower cost, and higher heat shock resistance. This review covers all main topics related to the science and technology of ablative materials with current and potential applications in the aerospace industry. After a short, yet comprehensive, introduction on non-ablative materials, this review paper summarizes fifty years of research efforts on polymeric ablatives, starting from the state of the art solutions currently used as TPS, up to covering the most recent efforts for nanostructuring their formulations. [ABSTRACT FROM AUTHOR]

The efficacy of polylactic acid (PLA)/Magnesium (Mg)-based materials for driving stem cells toward bone tissue engineering applications requires specific Mg surface properties to modulate the interface of stem cells with the film. Here, we have developed novel PLA/Mg-based composites and explored their osteogenic differentiation potential on human adipose stem cells (hASCs). Mg-particles/polymer interface was improved by two treatments: heating in oxidative atmosphere (TT) and surface modification with a compatibilizer (PEI). Different contents of Mg particles were dispersed in PLA and composite surface and bulk properties, protein adsorption, stem cell-PLA/Mg interactions, osteogenic markers expressions, and lipids composition profile were evaluated. Mg particles were uniformly distributed on the surface and in the bulk PLA polymer. Improved and modulated particle-polymer adhesion was observed in Mg particle-treated composites. After 21 days in canonical growth culture conditions, hASCs on PLA/MgTT displayed the highest expression of the general osteogenic markers, RUNX2, SSP1, and BGLAP genes, Alkaline Phosphatase, type I Collagen, Osteopontin, and Calcium deposits. Moreover, by LC/MS QTOF mass-spectrophotometry lipidomic analysis, we found in PLA/MgTT-cells, for the first time, a remodeling of the lipid classes composition associated with the osteogenic differentiation. We ascribed these results to MgTT characteristics, which improve Mg availability and composite osteoinductive performance. [ABSTRACT FROM AUTHOR]

The control of the nanostructure and the addition of nanoparticles to polymers have led to structural and functional property enhancements in a number of polymeric systems as a material answer to continuous requirements from advanced industrial sectors. The availability of new nanoparticles with extraordinary properties (i.e. carbon nanotubes, graphenes, but also nanoclays, nanocellulose, metals and ceramics) have determined new and exciting possibilities for a continuous enlargement of polymer markets. However, the potentialities of these new materials are still strongly dependent on the development and scaling-up of reliable processing routes. Therefore, the purpose of this report is to review the main processing approaches for nanostructured polymers and nanocomposites starting with a brief review of available nanoparticles and on their functionalization to promote a better polymer–particle interaction. Regarding processing, the review firstly addresses the bottom-up approaches typically adopted for nanostructured polymers, blends and copolymers. Then, the different technologies required by the top-down processing of thermoplastic and thermosetting polymer matrix systems are reviewed. Finally, the report addresses the recent applications of nanostructured polymers and nanocomposites as matrices of advanced composite materials. In all cases, the main processing approaches and the main structural and functional properties characterizing these materials and their potential and current industrial applications are specifically addressed. [ABSTRACT FROM AUTHOR]

In this work, we propose a wireless wearable system for the acquisition of multiple biopotentials through charge transfer electrostatic sensors realized in MEMS technology. The system is designed for low power consumption and low invasiveness, and thus candidates for long-time monitoring in free-living conditions, with data recording on an SD or wireless transmission to an external elaborator. Thanks to the wide horizon of applications, research is very active in this field, and in the last few years, some devices have been introduced on the market. The main problem with those devices is that their operation is time-limited, so they do not match the growing demand for long monitoring, which is a must-have feature in diagnosing specific diseases. Furthermore, their versatility is hampered by the fact that they have been designed to record just one type of signal. Using ST-Qvar sensors, we acquired an electrocardiogram trace and single-channel scalp electroencephalogram from the frontal lobes, together with an electrooculogram. Excellent results from all three types of acquisition tests were obtained. The power consumption is very low, demonstrating that, thanks to the MEMS technology, a continuous acquisition is feasible for several days. [ABSTRACT FROM AUTHOR]

Highlights: [•] The kinetics of a poly(urethane-isocyanurate) were modeled with an autocatalytic approach. [•] The relationship between the transition temperatures and conversion of the urethane and isocyanurate networks was measured with DSC analysis. [•] The urethane network was found to interact with the isocyanurate network through the vitrification effect. [•] A chemorheological model which contemplated the viscosity contribution of each network was proposed. [•] The chemorheological model was able to predict the experimental data and it was used to predict the behavior at elevated temperatures, where the rheometer was unable to measure the viscosity variation as a function of time. [Copyright &y& Elsevier]

The use of phase change materials (PCM) for thermal energy storage (TES) is of great relevance, especially for the exploitation, in various ways, of the major ecological resource offered by solar energy. Unfortunately, the transition to the liquid state of PCM requires complex systems and limits their application. The goal of producing shape-stabilized phase change materials (SSPCM) is mainly pursued with the use of media capable of containing PCM during solid/liquid cycles. In this work, four cheap shape stabilizers were considered: sepiolite, diatomite, palygorskite and zeolite and two molten salts as PCM, for medium (MT) and high temperature (HT). The SSPCM, produced with an energy saving method, showed good stability and thermal storage performances. Diatomite reaches up to 400% wt. of encapsulated PCM, with a shape stabilization coefficient (SSc) of 97.7%. Zeolite exhibits a SSc of 87.3% with 348% wt. of HT-PCM. Sepiolite contains 330% wt. of MT-PCM with an SSc of 82.7. Therefore, these materials show characteristics such that they can be efficiently used in thermal energy storage systems, both individually and inserted in a suitable matrix (for example a cementitious matrix). [ABSTRACT FROM AUTHOR]

This work reports on the development of starch-rich thermoplastic based formulations produced by using mango kernel flour, avoiding the extraction process of starch from mango kernel to produce these materials. Glycerol, sorbitol and urea at 15 wt% are used as plasticizers to obtain thermoplastic starch (TPS) formulations by extrusion and injection-moulding processes. Mechanical results show that sorbitol and urea allowed to obtain samples with tensile strength and elongation at break higher than the glycerol-plasticized sample, achieving values of 2.9 MPa of tensile strength and 42 % of elongation at break at 53 % RH. These results are supported by field emission scanning electron microscopy (FESEM) micrographs, where a limited concentration of voids was observed in the samples with sorbitol and urea, indicating a better interaction between starch and the plasticizers. Thermogravimetric analysis (TGA) shows that urea and sorbitol increase the thermal stability of TPS in comparison to the glycerol-plasticized sample. Differential scanning calorimetry (DSC) and dynamic-mechanical-thermal analysis (DMTA) verify the increase in stiffness of the sorbitol and urea plasticized TPS and also illustrate an increase in the glass transition temperature of both samples in comparison to the glycerol-plasticized sample. Glass transition temperatures of 45 °C were achieved for the sample with sorbitol. [ABSTRACT FROM AUTHOR]

Abstract: The alignment of single walled carbon nanotubes (SWCNTs) in an epoxy monomer liquid medium by the application of a DC electric field has been investigated, taking into account the various transport phenomena involved: the tube rotation in the electric field, the translation of polarized SWCNTs toward each other to form a chain-like structure and the migration of the tubes toward the positive electrode. Moreover, the relaxation mechanism which takes place when the electric field is switched off has also been considered. Experimental tests, performed to verify the effectiveness of the model, are based on the application of an electric field to a liquid epoxy–SWCNT colloid (0.025wt.%) while measuring the current and observing the system by optical microscopy. As a result of the modeling it is possible to identify the processing conditions that allow the alignment of SWCNTs in an epoxy resin through the short-time application of a DC electric field. Experimental measurements are in agreement with the model’s predictions. [Copyright &y& Elsevier]

Abstract: Polymer Layered Silicate Nanocomposites based on a commercial grade resol were produced using a simple, low labor cost, mechanical approach which allowed to avoid the process of intercalative polymerization of phenol and formaldehyde. Commercial compatibilized montmorillonite was selected as the main nanoreinforcement, while the matrix was a resol diluted in methanol. The aim of this work was to optimize the production technique of the above mentioned nanocomposites. Therefore intercalation of the resin was promoted by high speed mixing, and the processing parameters were varied in order to find the optimum dispersion. The produced nanocomposites were characterized and compared by means of X-ray diffraction, SEM and thermogravimetric analysis. The results of the characterization tests indicated that it was possible to obtain a good degree of dispersion as well as and uniform distribution of the nanoclay platelets. However, TGA measurements showed that the introduction of well dispersed nanoclays did not result in a consistent improvement of thermal stability respect that of the neat resol. [Copyright &y& Elsevier]

Abstract: We report how dodecanethiol (DT) surfactant can be used as a good dispersant to solubilize octadecylamine functionalized single-walled carbon nanotubes (ODA-SWCNTs) in order to confine them in the polystyrene phase of the polystyrene-b-polyisoprene-b-polystyrene (SIS) block copolymer matrix. It has been also demonstrated how the block copolymer matrix is not able to self-assemble in ordered morphology when the ODA-SWCNTs are not modified with the surfactant. DT assisted confinement of carbon nanotubes into the PS phase causes not only the nanostructuration of the host polymer matrix but also switches the self-assembled nanostructure from ordered cylinders in the case of neat SIS to a self-assembled lamellar nanostructure. [Copyright &y& Elsevier]

Thermoreversible physical gels of poly(styrene- b-butadiene- b-styrene) (SBS), formed by the dissolution of the block copolymer in a mid-block-selective solvent (THF), have been studied and characterized with particular attention to their morphology and rheological behavior. The effects of the addition of silver (Ag) nanoparticles to the SBS matrix, on the behavior of the physical gels, were also studied. The external surface of the Ag nanoparticles has been modified by using as surfactant material, dodecanethiol, in order to achieve their confinement in just one block of the SBS block copolymer matrix. The results of this study show that the gel stability is not affected by the presence of Ag nanoparticles. In fact, the micellar domains of the nanocomposite gel based on SBS block copolymer and Ag nanoparticles has been obtained and the physical gel behavior have been confirmed by rheological analysis. [ABSTRACT FROM AUTHOR]

Abstract: The intrinsic ability of block copolymers to self-assemble at nanoordered level into different nanoscale structures has been used in this study to obtain nanocomposites. Ordered architectures of silver nanoparticles confined in a poly(styrene-b-isoprene-b-styrene) (SIS) block copolymer matrix have been generated. Both cetyl trimethylammonium chloride (TMAC) and dodecanethiol (DT) were used as surfactants to obtain dispersed nanocomposite films. Morphologies generated in Ag/SIS nanocomposites, detected through atomic force, resulted to be more dependent on the amount of silver nanoparticles than on the other variables chosen in the present study such as amount and type of surfactant and preparation parameters. The experimental observations are consistent with phase diagram predictions obtained for hybrid systems composed of block copolymers and nanoparticles. [Copyright &y& Elsevier]

The aim of this work is to develop high‐performance adhesives to join carbon fiber reinforced composites (C/C) for use in aerospace applications; in order to guarantee sound mechanical strength, a low coefficient of thermal expansion, and ease of application on large components. Several different adhesive formulations, based on phenolic or cyanate‐ester resins (charged with the maximum experimentally feasible amount of carbon‐based fillers), are developed and tested. The measurements of the lap shear strength at room temperature of the C/C joined by means of one phenolic and one cyanate ester‐based resin demonstrates that these formulations are the most suitable for the given application. A complete characterization, by means of viscosimetry, dilatometry, and thermal gravimetric analysis, coupled with gas analysis by means of mass spectroscopy, confirms that the phenolic‐based formulation is the most promising joining material. A nano‐indenter is used to obtain its Young modulus and hardness, both inside the joint and as a bulk cured adhesive. [ABSTRACT FROM AUTHOR]

Poly(vinyl alcohol-co-ethylene) (EVOH) films containing zinc oxide nanorods (ZnO Nrods) at 0.1, 0.5, and 1 wt%, were realized by solvent casting. The effect of ZnO Nrods content on morphological, thermal, optical, mechanical, and oxygen permeability properties were analyzed. In addition, moisture content and accelerated-aging test studies were performed, with the intention to determine the influence of zinc oxide nanofillers on the functional characteristics of realized packaging systems. Tensile properties showed increased values for strength and deformation-at-break in EVOH-based formulations reinforced with 0.1 and 0.5 wt% of zinc oxide nanorods. Results from the colorimetric and transparency investigations underlined that the presence of ZnO Nrods in EVOH copolymer did not induce evident alterations. In addition, after the accelerated-aging test, the colorimetric test confirmed the possibility for these materials to be used in the packaging sector. This behavior was induced by the presence of zinc oxide nanofillers that act as a UV block that made them useful as an efficient absorber of UV radiation. [ABSTRACT FROM AUTHOR]

• Experimentally validated the durability and weatherability of a large area sensing skin for civil infrastructure. • An accelerated weathering chamber was used to apply a series of humidity, and UV radiation cycles to specimens manufactured for this study. A additional sensor deployed on a bridge in Iowa for six and a half years was removed from the field and analyzed in the laboratory • A variety of tests were performed to characterize the specimens' mechanical, thermal, optical, and electrical performance. Additionally, strain sensitivity analyses were performed on specimens of interest. • Results showed that titania inclusions improved the sensor dielectric's durability against weathering while the carbon black doped conductive layers provided the skin sensor with a high level of durability and weatherability protection. Structural health monitoring of civil infrastructure requires low-cost, scalable, long-term, and robust sensing technologies due to the size and complexity of the geometries under consideration. This paper investigates the durability and weatherability of a large area sensing skin engineered for civil infrastructure applications. This sensing skin is based on a soft elastomeric capacitor made of three thin layers based on an SEBS block co-polymer matrix. The inner layer is filled with titania and acts as the dielectric, while the external layers are doped with carbon black and work as the conductive plates. In this work, a variety of specimens, including the dielectric layer without the conductive plates, were fabricated and tested within an accelerated weathering chamber by simulating thermal, humidity, and UV radiation cycles. Beyond the accelerated weathering tests, a sensor deployed on a bridge in Iowa for six and a half years was removed from the field and analyzed in the laboratory. A variety of other tests were performed in order to characterize the specimens' mechanical, thermal, optical, and electrical performance. Additionally, strain sensitivity analyses were performed on specimens of interest. Results showed that titania inclusions improved the sensor dielectric's durability against weathering, while the carbon black doped conductive layers provided the skin sensor with a high level of durability and weatherability protection. The results in this work contribute to a better understanding of the degradation of SEBS-based matrices as well as the behavior of these skin sensors when deployed for the monitoring of civil infrastructure. [ABSTRACT FROM AUTHOR]

Abstract Novel multifunctional composite poly(lactic acid) (PLA) films with alginate microbeads containing silver nanoparticles (AgNPs) were developed for potential antimicrobial food packaging applications. AgNPs, 10–20 nm in size, were synthesized in a Na-alginate solution by a hydrothermal method yielding a sterile, pH neutral colloid solution of low viscosity that was electrostatically extruded to produce Ag/alginate microbeads (190 μm in size) with retained AgNPs. Dried microbeads were uniformly dispersed in PLA films with retained AgNPs as confirmed by UV–Vis spectroscopy and scanning electron microscopy. The films were characterized regarding thermal and mechanical properties as well as silver release in different food simulants. Results show that PLA matrix served as a diffusion barrier so that the released silver concentration in water after 10 days was within the prescribed limit of 0.05 mg kg−1 while the films induced inhibitory effects against Staphylococcus aureus in the agar diffusion test. Highlights • Low viscosity Ag/alginate colloid solutions were produced by hydrothermal synthesis • Electrostatic extrusion yielded microbeads with preserved silver nanoparticles • PLA composite films containing Ag/alginate microbeads were made by solvent casting. • PLA matrix in composite films served as a diffusion barrier for silver release. • PLA composite films inhibited the growth of S. aureus at low silver release. [ABSTRACT FROM AUTHOR]

Abstract Lignin nanoparticles (LNP) have been esterified and etherified by citric acid and then blended with poly (vinyl alcohol) (PVA) at various loading levels (up to 10 wt%). Poly(vinyl alcohol) nanocomposite films containing unmodified and modified lignin nanoparticles (LNP and MLNP) were prepared through solvent casting approach. Microscopic investigation of films fractured surfaces confirmed that MLNP could be evenly dispersed in PVA matrix, and no macroscopic phase separation was generated in the nanocomposite films. Water contact angle, swelling efficiency and moisture adsorption properties of LNP and MLNP based films were measured and compared, revealing an overall increase of dimensional stability and reduced moisture adsorption for MLNP nanocomposites. MLNP based nanocomposite films outperformed the films containing LNP in antioxidant property and transparency, slight sacrificing in UV-absorbing, confirming these materials as promising candidates for applications requiring high antioxidant potential and improved performance towards light absorbance. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Highlights • Waxy and non-waxy barley flours were selected for the extraction of starch nanoparticles. • Organic and alkali treatments were adopted to purify the barley waxy cultivar. • Nanoparticles with reduced mean diameter and thermal stability originated from waxy starch. • Amorphous nanoparticles derived from waxy and non-waxy barley starches were extracted. Abstract Waxy and non-waxy barley flours were selected as native material for the extraction, by acidic hydrolysis, of starch nanoparticles (NPs), with the main aim of evaluating how their different amylose/amylopectin ratio affected NPs structural characteristics. To this scope, two approaches based, respectively, on the use of NaCl/toluene (called organic treatment) and of sodium hydroxide solutions (called alkali treatment) were adopted in order to purify the waxy flours to give starch granules. Morphological investigations of waxy flour after alkali and organic treatments, before and after acetone washing, showed that the isolation methods of the starch did not affect the general morphologic characteristics of starch granules. The method found to provide the best outcomes in terms of thermal and morphological properties was also applied to purify the non-waxy barley. The results confirmed that waxy starch characterized by granules of smaller dimensions (WS) gave amorphous nanoparticles (WNP) with reduced mean diameter and thermal stability with respect to NPs obtained from non-waxy barley flour. [ABSTRACT FROM AUTHOR]

Abstract This work investigated, for the first time, the role of nanosized lignin (LNP), in comparison with microlignin (LMP), when introduced at two different weight amounts (5% and 10 wt%) in bulk phenol–formaldehyde resol as adhesive. Morphological analysis was performed to check out the dispersion and interfacial bonding of lignin in the phenolic resin. The curing process has been examined by differential scanning calorimetry (DSC), while the thermal stability of the composites has been evaluated by using thermogravimetric (TGA) and thermo-mechanical (TMA) analysis. Results exhibited that small amount of lignin could both favor the thermal cure reaction, due to its abundance of phenylpropane units, and the initial thermal resistance could be consequently improved, especially when the nano-sized lignin was used. Meanwhile, the effect of micro- and nano-modification on tensile shear strength of wood lap joints based on lignin-phenol–formaldehyde resol adhesives was also analyzed. Results showed that 5 wt% of LNP could positively increase the shear strength from 8.7 to 10.9 MPa, opening the possibility of using environmental friendly nanoscale lignin in cross linked traditional phenol wood adhesives with enhanced adhesion performance, strongly related to nanoparticles higher specific surface area and reactivity. Graphical abstract Unlabelled Image Highlights • Nanosized (LNP) and microlignin (LMP) were added to phenol–formaldehyde resol adhesive. • Nanolignin could both favor the cure reaction, due to its abundance of phenylpropane units. • Nanosized lignin homogenously dispersed absorbed and inhibited dimensional changes. • Higher specific surface area and reactivity for LNP increase the shear strength of wood joints. [ABSTRACT FROM AUTHOR]

Abstract The study evaluated the effects of 4 wt% nanohydroxyapatite (HA), 6 wt% zinc l -carnosine (MDA) and 1.5 wt% Ciprofloxacin (AB) on the mechanical, thermal and biological properties of glass ionomer cements (GIC). Filler and additive concentrations were selected after a previous study had tested single components and different percentages. Specimens included five silicon molds of each GIC cement for all tests. They were stored at room temperature for 24 h from specimen collection to analysis. Mechanical tests, calorimetric analysis, morphological investigation, antibacterial and cell viability assays were conducted. One-way analysis of variance (ANOVA) was used for data analysis with significance set at p < 0.05. Adding HA, MDA and AB to GICs modified their thermal, mechanical and microbiological properties. Polymerization increased. A slight decrease in the compressive strength of modified GICs was observed in dry condition (p < 0.05). Cement extracts affected cell viability in relation to extract dilution. Mechanical behavior improved in modified glass ionomer cements, especially with the powder formulated antibiotic. Overall cytotoxicity was reduced. Therefore adding nanohydroxyapatite, antibiotic and a mucosal defensive agent to conventional glass ionomer cement in special need patients could improve the clinical, preventive and therapeutic performance of the cements, without altering their mechanical properties. Highlights • Effects of modified GIC on human oral cells • GIC and modified GIC have variable effects on oral tissue in vitro. • HA, ciprofloxacin and zinc l -carnosine modify the mechanical properties of GICs. [ABSTRACT FROM AUTHOR]

Abstract In this contribution, binary blends of thermoplastic starch (TPS) and poly(butylene trans -1,4-cyclohexanedicarboxylate) (PBCE) have been prepared by melt extrusion. The effect of different amounts of PBCE and the presence of citric acid as compatibilizer have been studied with respect to the blend behavior. In particular, morphological and thermal studies allowed for the determination of the compatibility between the blend components, and of their characteristic thermal transitions and thermal stability. Envisioning potential packaging applications, surface wettability, moisture absorption and migration of food simulant have been investigated. In addition, mechanical properties and gas permeability have been evaluated after conditioning the films in dry and humid environment. Highlights • Blends of thermoplastic starch and poly(butylene trans -1,4-cyclohexanedicarboxylate) have been prepared by melt extrusion. • The effect of blend composition and of the presence of citric acid have been studied with respect to the blend behavior. • Compatibilized binary blends are characterized by improved mechanical and barrier properties to oxygen and carbon dioxide. [ABSTRACT FROM AUTHOR]

Novel ternary films have been realized by using poly(vinyl alcohol) (PVA) as polymeric matrix, nanostructured starch as reinforcement phase and hydroxytyrosol (HTyr), a low-molecular phenolic compound present in olive oil, as antioxidant agent. Nanostructured starch, in the form of starch nanocrystals (NC) and nanoparticles (NP) obtained by acid hydrolysis and ultrasound irradiation of starch derived from the bread wheat variety Cadenza (WT, amylose content 33%) and a derived-high amylose line (HA, amylose content 75%), was considered. The developed multifunctional films were characterized in terms of morphological, thermal and optical properties, water absorption capacity, overall and specific migration into a food simulant and antioxidant properties. Experimental data showed a prolonged release of HTyr from all ternary films and the released HTyr retained a strong antioxidant activity. The data, compared to those of PVA/HTyr binary films, demonstrated the key role of nanostructured starch in the ternary formulations in promoting a gradual release of HTyr. Overall, PVA fillm combined with nanoparticles from low amylose starch and hydroxytyrosol resulted as the most promising ternary formulation for food packaging applications. [ABSTRACT FROM AUTHOR]

Clear-sky conditions are an essential need to allow proper high-temperature solar cooking. Moreover, it is not an easy task to accomplish evening cooking, especially during wintertime when solar radiation is available only for a few hours. A solution to bypass these drawbacks lies in adopting a cooker provided with a thermal storage unit. The storage unit proposed in this work is a double-walled vessel composed by two stainless steel cylindrical pots assembled concentrically. The annular space between the pots was loaded with 4 kg of phase change material (PCM) based on a ternary mixture of nitrite and nitrate salts (solar salt: 53 wt% KNO 3 , 40 wt% NaNO 2 , 7 wt% NaNO 3 ). The thermal storage unit was characterized by means of a test rig including a high-concentration-ratio (10.78) solar box cooker. Four different sets of 14 experimental tests, divided into a heating and a cooling phase, were carried out to assess the performance of the solar cooker with the storage unit. It was found that the PCM thermal storage significantly improves the load thermal stabilization when solar radiation is not available: the load cooling time in the range 170–130 °C was determined to be from 65.12% to 107.98% higher than that without the solar-salt-based PCM thermal storage, proving the effectiveness of the proposed solution. [ABSTRACT FROM AUTHOR]

This work investigates the feasibility of using coffee silverskin (CSS), one of the most abundant coffee waste products, as a reinforcing agent in biopolymer based composites. The chemical composition, antioxidant activity and morphology of CSS were studied by specific chemical essays and scanning electron microscopy, whilst the thermal stability and the functional groups available on the surface were investigated by thermogravimetric analysis and infrared spectroscopy, respectively. The thermal stability and fibrous structure of CSS make it suitable as a reinforcing filler in polymer composites, which was confirmed by manufacturing biocomposites with improved stiffness and tensile strength, not degraded by CSS addition when compared to the neat biopolymer. [ABSTRACT FROM AUTHOR]

There was a hope that highly reactive nanoparticles would strongly facilitate crosslinking in epoxy-amine systems. In this work, silica (SiO 2 ) nanoparticles are physically modified with poly(ethyleneimine) as surface modifier. The SiO 2 nanoparticles were synthesized and physically decorated with poly(ethyleneimine), then the untreated and surface-treated SiO 2 nanoparticles were analyzed by FTIR, TGA and SEM techniques. The results show that poly(ethyleneimine) hyperbranched molecule is successfully attached to the surface of SiO 2 nanoparticles enabling epoxy ring opening. Both untreated and modified particles are impregnated into an epoxy/amine system to fabricate nanocomposite coatings. The effect of the aforementioned SiO 2 nanoparticles on the curing behavior of the epoxy/amine system was investigated by means of dynamic DSC analysis. The results demonstrated that, while addition of untreated silica nanoparticles could not seriously curing reactions, the introduction of poly(ethyleneimine)-modified SiO 2 facilitated crosslinking of epoxy/amine system thanks to the abundance of amine reactive groups on the particle surface that gives worth to the poly(ethyleneimine)-modified SiO 2 nanoparticles as a promising nanomaterial for manufacturing highly-curable epoxy-based nanocomposite coatings. [ABSTRACT FROM AUTHOR]

Magnetic nanoparticles embedded in polymer matrices have excellent potential for electromagnetic device applications, like electromagnetic interference suppression or strain sensing applications in the structural health monitoring domain. In this work, polymer nanocomposites of polypropylene loaded with varying concentrations of magnetite nanoparticles (from 2 to 40 wt%) have been synthesized by an ex situ process. The magnetite nanoparticles were produced using a simple co‐precipitation technique. The nanocomposites were characterized by differential scanning calorimetry, scanning electron microscopy, tensile and hardness testing, vibrating sample magnetometry. The mechanical properties were found to be dependent on the degree of dispersion and on the strong nucleating ability of magnetite nanoparticles, while a superparamagnetic behavior was reported. These composites have tailorable mechanical and magnetic properties highly dependent on the content of magnetic filler. POLYM. COMPOS., 39:E1742–E1750, 2018. © 2018 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

In this work the thermally-activated shape memory response of biodegradable nanocomposites based on PLA/PCL blend reinforced with different type of cellulose nanocrystals has been reported, and compared with those of the neat matrix, at the same transition temperature of 55 °C and at the same different deformations, 50%, 100% and 150%. In particular, cellulose nanocrystals have been synthesized and then functionalized by “grafting from” reaction by ring opening polymerization of both PLLA and PCL using the OH groups onto the cellulose nanocrystals surface as initiators for the reaction. The morphology, thermal and mechanical analysis have been performed in order to obtain the parameters for the thermo-mechanical shape memory cycles. Moreover, the addition of the CNC-based nanofillers on the compatibility of PLA-PCL blends in 70:30 proportion has been evaluated. All the biodegradable nanocomposite formulations showed excellent shape memory response, similar to those of the neat matrix, with strain recovery ratio and strain fixity ratio higher than 80% and 90%, respectively. This fact indicates that in this case, the shape memory response of the nanocomposites is mainly controlled by the response of the neat blend and they are slightly influenced by the increase of compatibility between the components of the blend. In addition, all nanocomposite films were fully disintegrated under composting conditions confirming their biodegradable nature, obtaining that the presence of CNC-based nanofillers speeds up the disintegration rate of the nanocomposites in comparison with the pure matrix. [ABSTRACT FROM AUTHOR]

In this work, the effect of the addition of different amount of nanosized hydroxyapatite (nHA) on the shape memory behavior of blends based on poly (lactic acid) (PLA) and poly (ε-caprolactone) (PCL) has been studied. In particular PLA/PCL blend with 70 wt % PLA has been reinforced with 0.5, 1 and 3 wt % nHA. Moreover, the relationship between the morphology and the final properties of the nanocomposites has been investigated by field emission scanning electron microscopy, confocal Raman spectroscopy and atomic force microscopy. In particular, PeakForce has been used to study quantitative nanomechanical properties of the multifunctional materials leading to conclusion that nHA increase the phase separation between PLA and PCL as well as act as reinforcements for the PCL-rich phase of the nanocomposites. Furthermore, excellent thermally-activated shape memory response has been obtained for all the nanocomposites at 55 °C. Finally, the disintegration under composting conditions at laboratory scale level was studied in order to confirm the biodegradable character of these nanocomposites. Indeed, these materials are able to be used for biomedical issues as well as for packaging applications where both thermally-activated shape memory effect and biodegradability are requested. [ABSTRACT FROM AUTHOR]

In this study, different nanofluids (NFs) were developed by mixing a molten salt mixture (60% NaNO3-40% KNO3) with 1.0 wt % of silica-alumina nanoparticles using different methods. These NFs can be used as thermal energy storage materials in concentrating solar plants with a reduction of storage material if the thermal properties of the base fluid are increased. New mixing procedures without sonication were introduced with the aim to avoid the sonication step and to allow the production of a greater amount of NF with a procedure potentially more suitable for large-scale productions. For this purpose, two mechanical mixers and a magnetic stirrer were used. Each NF was prepared in aqueous solution with a concentration of 100 g/l. The effect of different concentrations (300 g/l and 500 g/l) was also studied with the most effective mixer. Specific heat, melting temperature, and latent heat were measured by means of differential scanning calorimeter. Thermal conductivity and diffusivity in the solid state were also evaluated. The results show that the highest increase of the specific heat was obtained with 100 g/l both in solid (up to 31%) and in liquid phase (up to 14%) with the two mechanical mixers. The same NFs also showed higher amount of stored heat. An increase in thermal conductivity and diffusivity was also detected for high solution concentrations with a maximum of 25% and 47%, respectively. Scanning electron microscopy (SEM) and energy-dispersive X-ray analyses revealed that the grain size in the NFs is much smaller than in the salt mixture, especially for the NF showing the highest thermal properties increase, and a better nanoparticles distribution is achieved with the lowest concentration. NFs with enhanced thermal properties can be synthesized in a cost-effective form in high concentrated aqueous solutions by using mechanical mixers. [ABSTRACT FROM AUTHOR]

The availability of new self-sensing cement-based strain sensors allows the development of dense sensor networks for Structural Health Monitoring (SHM) of reinforced concrete structures. These sensors are fabricated by doping cement-matrix mterials with conductive fillers, such as Multi Walled Carbon Nanotubes (MWCNTs), and can be embedded into structural elements made of reinforced concrete prior to casting. The strain sensing principle is based on the multifunctional composites outputting a measurable change in their electrical properties when subjected to a deformation. Previous work by the authors was devoted to material fabrication, modeling and applications in SHM. In this paper, we investigate the behavior of several sensors fabricated with and without aggregates and with different MWCNT contents. The strain sensitivity of the sensors, in terms of fractional change in electrical resistivity for unit strain, as well as their linearity are investigated through experimental testing under both quasi-static and sine-sweep dynamic uni-axial compressive loadings. Moreover, the responses of the sensors when subjected to destructive compressive tests are evaluated. Overall, the presented results contribute to improving the scientific knowledge on the behavior of smart concrete sensors and to furthering their understanding for SHM applications. [ABSTRACT FROM AUTHOR]

In this study, nanocomposites based on polyethersulfone (PES) with different amounts of Fe 3 O 4 nanoparticles have been synthesized, to be used as proton exchange membranes in a microbial fuel cell (MFC). Such new low-cost separators were fabricated by melt blending and tested in an MFC system. The membranes have been characterized in terms of their mechanical and thermal properties and the results compared to those of commercially available ones (Nafion 117 and CMI 7000). The efficiency of the newly synthesized membranes was assessed in H-type MFC system. Synthetic wastewater using sodium acetate as carbon source was prepared. Total Organic Carbon (TOC) reduction, pH and Open Circuit Voltage (OCV) were daily monitored. Linear Sweep Voltammetry (LSV) was used to optimize the amount of nanoparticles in terms of maximum current and power. The maximum power (9.59 ± 1.18 mW m −2 ) and current density (38.38 ± 4.73 mA m −2 ) generation were obtained by using a composite with 20 wt% of nanoparticles. Results of mechanical characterization pointed out that increasing nanoparticles content can compromise the mechanical properties of membranes leading to a significant brittle behavior, while the tensile strength was found to be suitable for durable MFC operations. [ABSTRACT FROM AUTHOR]

Poly(hydroxybutyrate) (PHB)-based films, reinforced with bacterial cellulose (BC) or cellulose nanocrystals (CNC) and plasticized using a molecular (tributyrin) or a polymeric plasticizer (poly(adipate diethylene)), were produced by solvent casting. Their morphological, thermal, wettability, and chemical properties were investigated. Furthermore, the effect of adding both plasticizers (20 wt % respect to the PHB content) and biobased selected nanofillers added at different contents (2 and 4 wt %) on disintegrability in composting conditions was studied. Results of contact angle measurements and calorimetric analysis validated the observed behavior during composting experiments, indicating how CNC aggregation, due to the hydrophilic nature of the filler, slows down the degradation rate but accelerates it in case of increasing content. In contrast, nanocomposites with BC presented an evolution in composting similar to neat PHB, possibly due to the lower hydrophilic character of this material. The addition of the two plasticizers contributed to a better dispersion of the nanoparticles by increasing the interaction between the cellulosic reinforcements and the matrix, whereas the increased crystallinity of the incubated samples in a second stage in composting provoked a reduction in the disintegration rate. [ABSTRACT FROM AUTHOR]

Kiwi Actinidia deliciosa pruning residues were here used for the first time as precursors for the extraction of high performing cellulose nanocrystals (CNC) by applying a bleaching treatment followed by an acidic hydrolysis. The resultant cellulosic nanostructures, obtained by an optimize extraction procedure (0.7% wt/v two times of sodium chlorite NaClO 2 ) followed by an hydrolysis step, were then used as reinforcements phases in poly(vinyl alcohol) (PVA) blended with natural chitosan (CH) based films and also combined, for the first time, with carvacrol used here as active agent. Morphological and optical characteristics, mechanical response, thermal and migration properties, moisture content and antioxidant and antimicrobial assays were conducted. The morphological, optical and colorimetric results underlined that no particular alterations were induced on the transparency and color of PVA and PVA_CH blend by the presence of CNC and carvacrol, while they were able to modulate the mechanical responses, to induce antioxidant activities maintaining the migration levels below the permitted limits and suggesting the possible application in industrial sectors. Finally, inhibitions on bacterial development were detected for multifunctional systems, suggesting their protective function against microorganisms contamination. [ABSTRACT FROM AUTHOR]

This work shows that the active interaction between human umbilical cord matrix stem cells and Poly ( l -lactide)acid (PLLA) and PLLA/Multi Walled Carbon Nanotubes (MWCNTs) nanocomposite films results in the stem cell assembly as a spheroid conformation and affects the stem cell fate transition. We demonstrated that spheroids directly respond to a tunable surface and the bulk properties (electric, dielectric and thermal) of plain and nanocomposite PLLA films by triggering a mechanotransduction axis. This stepwise process starts from tethering of the cells' focal adhesion proteins to the surface, together with the adherens junctions between cells. Both complexes transmit traction forces to F-Actin stress fibres that link Filamin-A and Myosin-IIA proteins, generating a biological scaffold, with increased stiffening conformation from PLLA to PLLA/MWCNTs, and enable the nucleoskeleton proteins to boost chromatin reprogramming processes. Herein, the opposite expression of NANOG and GATA6 transcription factors, together with other lineage specification related proteins, steer spheroids toward an Epiblast-like or Primitive Endoderm-like lineage commitment, depending on the absence or presence of 1 wt% MWCNTs, respectively. This work represents a pioneering effort to create a stem cell/material interface that can model the stem cell fate transition under growth culture conditions. [ABSTRACT FROM AUTHOR]