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In the past 20 years, scientific research focused on the identification of valid alternatives to materials of fossil origin, in particular, related to biobased polymers. Recently, the efforts led to the synthesis of thiophene-based polymers (TBPs), a new class of polyesters based on 2,5-thiophenedicarboxylic acid (TPCA) that can be industrially produced using biomass-derived molecules. In this study, TBPs were synthesized using diols with different chain length (from C4 to C6) leading to poly(butylene 2,5-thiophenedicarboxylate) (PBTF), poly(pentamethylene 2,5-thiophenedicarboxylate) (PPeTF), and poly(hexamethylene 2,5-thiophenedicarboxylate) (PHTF), respectively, that were processed to thin films. To investigate enzymatic hydrolysis of these polymer films, cutinase 1 (Thc_cut1) and cutinase 2 (Thc_cut2) from Thermobifida cellulosilytica were recombinantly expressed in the host E. coli and purified. After 72 h of incubation at 65°C with 5 µM Thc_cut1, weight loss and HPLC analysis indicated 9, 100, and 80% degradation of PBTF, PPeTF, and PHTG with a concomitant release of 0.12, 2.70, and 0.67 mM of TPCA. The SEM analysis showed that tiny holes were formed on the surface of the films and after 72 h PPeTF was completely degraded. The LC-TOF/MS analysis indicated that Thc_cut2 in particular released various oligomers from the polymer during the reaction. In addition, the FTIR analysis showed the formation of novel acid and hydroxyl groups on the polymer surfaces. The results showed that the two used thermostable cutinases are promising biocatalysts for the environmentally friendly degradation of TPCA-based polyesters, in view of a possible sustainable recycling of plastic waste through resynthesis processes.

In the present study, 100% bio-based polyesters of 2,5-thiophenedicarboxylic acid were synthesized via two-stage melt polycondensation using glycols containing 3 to 6 methylene groups. The so-prepared samples were characterised from the molecular point of view and processed into free-standing thin films. Afterward, both the purified powders and the films were subjected to structural and thermal characterisation. In the case of thin films, mechanical response and barrier properties to O2 and CO2 were also evaluated. From the results obtained, it emerged that the length of glycolic sub-units is an effective tool to modulate the chain mobility and, in turn, the kind and amount of ordered phases developed in the samples. In addition to the usual amorphous and 3D crystalline phases, in all the samples investigated it was possible to evidence a further phase characterised by a lower degree of order (mesophase) than the crystalline one, whose amount is strictly related to the glycol sub-unit length. The relative fraction of all these phases is responsible for the different mechanical and barrier performances. Last, but not least, a comparison between thiophene-based homopolymers and their furan-based homologues was carried out.

Among the several actions contributing to the development of a sustainable society, there is the eco-design of new plastic materials with zero environmental impact but that are possibly characterized by properties comparable to those of the traditional fossil-based plastics. This action is particularly urgent for food packaging sector, which involves large volumes of plastic products that quickly become waste. This work aims to contribute to the achievement of this important goal, proposing new bio-based cycloaliphatic polymers based on trans-1,4-cyclohexanedicarboxylic acid and containing different amount of camphoric acid (from 0 to 15 mol %), a cheap and bio-based building block. Such chemical modification was conducted in the melt by avoiding the use of solvents. The so-obtained polymers were processed in the form of films by compression molding. Afterwards, the new and successfully synthesized random copolymers were characterized by molecular (NMR spectroscopy and GPC analysis), thermal (DSC and TGA analyses), diffractometric (wide angle X-ray scattering), mechanical (through tensile tests), and O2 and CO2 barrier point of view together with the parent homopolymer. The article aims to relate the results obtained with the amount of camphoric moiety introduced and to present, the different microstructure in the copolymers in more detail, indeed, in these samples, a different crystalline form developed (the so-called β-PBCE). This latter form was the kinetically favored and less packed one, as proven by the lower equilibrium melting temperature determined for the first time by Baur’s equation.

Here, solution-cast blends of polylactic acid (PLA) and a novel bioderived poly(pentamethylene 2,5-furanoate) (PPeF) in variable concentrations (1-50 wt %) are prepared and investigated. The characterization of the thin films (thickness 50 mu m) highlights that PPeF strongly improves the UV-shielding properties of PLA, with a decrease in transmittance at 275 nm from 47.3% of neat PLA to 0.77% with only 1 wt % of PPeF, while the transmittance decrease in the visible region at these PPeF fractions is marginal, allowing the production of optically transparent films. Despite the complete immiscibility of PLA/PPeF blends, PPeF effectively enhances the ductility of PLA as the tensile strain at break increases from 7% of neat PLA to 200% of the blend with 30 wt % of PPeF. This composition is the most promising also from the gas-barrier point of view as the gas transmission rates of CO2 and O-2 drop to one-fourth of those of neat PLA, comparable to those of poly(ethylene terephthalate). These results highlight that PLA/PPeF blends with PPeF fractions of 30 wt % are very promising for food packaging applications, and their properties could be further enhanced by applying suitable compatibilizers.

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.

In the present work, the effect of ether oxygen atom introduction in a furan ring-containing polymer has been evaluated. Solvent-free polycondensation process permitted the preparation of high molecular weight poly(diethylene 2,5-furandicarboxylate) (PDEF), by reacting the dimethyl ester of 2,5-furandicarboxylic acid with diethylene glycol. After molecular and thermal characterization, PDEF mechanical response and gas barrier properties to O2 and CO2, measured at different temperatures and humidity, were studied and compared with those of poly(butylene 2,5-furandicarboxylate) (PBF) and poly(pentamethylene 2,5-furanoate) (PPeF) previously determined. Both PDEF and PPeF films were amorphous, differently from PBF one. Glass transition temperature of PDEF (24 °C) is between those of PBF (39 °C) and PPeF (13 °C). As concerns mechanical response, PDEF is more flexible (elastic modulus [E] = 673 MPa) than PBF (E = 1290 MPa) but stiffer than PPeF (E = 9 MPa). Moreover, PDEF is the most thermally stable (temperature of maximum degradation rate being 418 for PDEF, 407 for PBF and 414 °C for PPeF) and hydrophilic (water contact angle being 74° for PDEF, 90° for PBF and 93° for PPeF), with gas barrier performances very similar to those of PPeF (O2 and CO2 transmission rate being 0.0022 and 0.0018 for PDEF and, 0.0016 and 0.0014 cm3 cm/m2 d atm for PPeF). Lab scale composting experiments indicated that PDEF and PPeF were compostable, the former degrading faster, in just one day. The results obtained are explained on the basis of the high electronegativity of ether oxygen atom with respect to the carbon one, and the consequent increase of dipoles along the macromolecule.

Furanoate polyesters are emerging as promising bioderived polymers that could replace petrochemical-derived polyesters in several applications, for example, the textile field. Here, sustainable and fully bioderived fibers are wet-spun by blending poly(lactic acid) (PLA) and poly(pentamethylene 2,5-furanoate) (PPeF), with up to 50 wt% of PPeF. PLA/PPeF blends result as immiscible, with PPeF domains homogeneously distributed within the PLA matrix, as shown by scanning electron micrographs. The immiscibility is confirmed by differential scanning calorimetry, as the glass transition temperature of PLA is unaffected by PPeF. The immiscibility and poor adhesion between PLA and PPeF are responsible for the decrease in stress at break and elongation at break from 30.1MPa and 127%, of PLA fibers, to 3.5MPa and 1.9%, at high PPeF amounts. However, the addition of PPeF strongly decreases the PLA's tendency to absorb water and retain the processing solvents, showing a mass loss decrease from 3.1% for PLA fibers to 1% for fibers containing 50 wt% PPeF, thereby addressing one of the main drawbacks of PLA. These results, although preliminary, offer new directions for future works on innovative and sustainable fibers based on furanoate polyesters.

The overall migration behavior and the disintegration under composting conditions of films based on plasticized poly(lactic acid)/poly(3-hydroxybutyrate) (PLA-PHB) blends were studied, with the main aim of determining the feasibility of their application as biodegradable food packaging materials. The role of composition in the disintegration process was evaluated by monitoring the changes in physical and thermal properties that originated during the degradation process. PLA and PHB were blended in two weight ratios with 15 wt% of tributyrin, using a Haake mixer and then compression molded into ~150 μm films. We found that the migration level of all of the studied blends was below check intended meaning retained in non-polar simulants, while only plasticized blends could withstand the contact with polar solvents. The disintegration of all of the materials in compost at 58 °C was completed within 42 days, the plasticized PHB underwent the fastest degradation, taking only 14 days. The presence of the TB plasticizer speeded up the degradation process. Different degradation mechanisms were identified for PLA and PHB. To evaluate the annealing effect separately from bacteria degradation, the influence of temperature on materials in the absence of a compost environment was also studied. With the increasing time of degradation in compost, both melting temperature and maximum degradation temperature progressively decreased, while the crystallinity degree increased, indicating that the samples were definitely degrading and that the amorphous regions were preferentially eroded by bacteria.

Polymer nanostructures were developed on fully bio-based poly(trimethylene furanoate) (PTF) films, by using the technique of Laser Induced Periodic Surface Structures (LIPSS). We found that irradiation times between 1 and 8 min allowed the formation of periodic and nanometric ripples, when using an UV pulsed laser source at a fluence of 8 mJ/cm2. The wrinkled surfaces were studied by a combined macro- and nanoscale approach. We evaluated possible physicochemical changes taking place on the polymer surface after irradiation by infrared spectroscopy, contact angle measurements and atomic force microscopy. The macroscopic properties of PTF showed almost no changes after nanostructure formation, differently from the results previously found for the terephthalic counterparts, as poly(ethylene terephthalate), PET, and poly(trimethylene terephthalate), PTT. At the nanoscale, the surface mechanical properties of the nanostructured PTF were found to be improved, as evidenced by force spectroscopy measurements. In particular, stiffer surfaces characterized by an increased Young's modulus were measured for the nanostructured sample., This work has been supported by Ministry of Science, Innovation and Universities (MCIU, Spain) under the project CTQ2016-75880-P. D.E.M. acknowledges the financial support obtained through the Post-Doctoral fellowship “Juan de la Cierva – Incorporación” (IJCI-2017-31600, MCIU, Spain). E.R. thanks MCIU for the tenure of a Ramón y Cajal contract (No. RYC-2011-08069).

Thanks to the continuous progress of tissue engineering, the opportunity to overcome the main limits of traditional medicine is becoming more and more concrete. By a targeted study of biomaterials and their properties, it is possible to find ad hoc solutions for the fabrication of tissue engineered scaffolds. More in details, poly(butylene succinate) PBS is a biocompatible synthetic polymer already investigated for biomedical applications, but characterized by a high degree of crystallinity, which leads to long degradation times and mechanical properties often not suitable in the field of soft tissue engineering. In the present study, a PBS-based copolymer containing 30 mol% of dithiodipropionic co-units, P(BSBDTDP), was synthesized by two-step melt polycondensation. The comonomeric unit is characterized by the presence of -S-S- bond, potentially capable of improving both biocompatibility and biodegradability with respect to the homopolymer. After synthesis, 3D-mats and films were obtained by electrospinning and compression moulding, respectively, and then subjected to molecular, thermal and mechanical characterization. In addition, in view of a possible application in soft tissue engineering, enzymatic biodegradation studies and in vitro biocompatibility tests, using NIH-3T3 cell line, were also carried out. The results obtained show that through copolymerization solid-state properties could be nicely tailored. More in details, compared to PBS, P(BSBDTDP) is characterized by a lower crystallinity degree and mechanical properties typical of soft tissues, maintaining at the same time the good thermal stability of the parent homopolymer. In addition, copolymeric scaffold better supports cell adhesion and proliferation, undergoing degradation in biological environment slightly faster than its PBS homologous. (C) 2020 Elsevier Ltd. All rights reserved.

Herein, we present poly(butylene 1,4-cyclohexanedicarboxylate) (PBCE) films characterized by an unpatterned microstructure and a specific hydrophobicity, capable of boosting a drastic cytoskeleton architecture remodeling, culminating with the neuronal-like differentiation of human bone marrow-mesenchymal stem cells (hBM-MSCs). We have used two different filming procedures to prepare the films, solvent casting (PBCE) and compression-moulding (PBCE*). PBCE film had a rough and porous surface with spherulite-like aggregations (&Oslash, = 10&ndash, 20 &mu, m) and was characterized by a water contact angle = 100&deg, PBCE* showed a smooth and continuous surface without voids and visible spherulite-like aggregations and was more hydrophobic (WCA = 110&deg, ). Both surface characteristics were modulated through the copolymerization of different amounts of ether-oxygen-containing co-units into PBCE chemical structure. We showed that only the surface characteristics of PBCE-solvent-casted films steered hBM-MSCs toward a neuronal-like differentiation. hBM-MSCs lost their canonical mesenchymal morphology, acquired a neuronal polarized shape with a long cell protrusion (&ge, 150 &mu, m), expressed neuron-specific class III &beta, tubulin and microtubule-associated protein 2 neuronal markers, while nestin, a marker of uncommitted stem cells, was drastically silenced. These events were observed as early as 2-days after cell seeding. Of note, the phenomenon was totally absent on PBCE* film, as hBM-MSCs maintained the mesenchymal shape and behavior and did not express neuronal/glial markers.

11 pags., 7 figs., 4 tabs., In the present paper, four fully biobased homopolyesters of 2,5-furandicarboxylic acid (2,5-FDCA) with a high molecular weight have been successfully synthesized by two-stage melt polycondensation, starting from the dimethyl ester of 2,5-FDCA and glycols of different lengths (the number of methylene groups ranged from 3 to 6). The synthesized polyesters have been first subjected to an accurate molecular characterization by NMR and gel-permeation chromatography. Afterward, the samples have been successfully processed into free-standing thin films (thickness comprised between 150 to 180 μm) by compression molding. Such films have been characterized from the structural (by wide-angle X-ray scattering and small-angle X-ray scattering), thermal (by differential scanning calorimetry and thermogravimetric analysis), mechanical (by tensile test), and gas barrier (by permeability measurements) point of view. The glycol subunit length was revealed to be the key parameter in determining the kind and fraction of ordered phases developed by the sample during compression molding and subsequent cooling. After storage at room temperature for one month, only the homopolymers containing the glycol subunit with an even number of-CH2-groups (poly(butylene 2,5-furanoate) (PBF) and poly(hexamethylene 2,5-furanoate) (PHF)) were able to develop a three-dimensional ordered crystalline phase in addition to the amorphous one, the other two appearing completely amorphous (poly(propylene 2,5-furanoate (PPF) and poly(pentamethylene 2,5-furanoate) (PPeF)). From X-ray scattering experiments using synchrotron radiation, it was possible to evidence a third phase characterized by a lower degree of order (one-or two-dimensional), called a mesophase, in all the samples under study, its fraction being strictly related to the glycol subunit length: PPeF was found to be the sample with the highest fraction of mesophase followed by PHF. Such a mesophase, together with the amorphous and the eventually present crystalline phase, significantly impacted the mechanical and barrier properties, these last being particularly outstanding for PPeF, the polyester with the highest fraction of mesophase among those synthesized in the present work., G.G., M.S., N.L., and A.M. acknowledge the Italian Ministry of University and Research. This publication is based upon work from COST Action FUR4Sustain, CA18220, supported by COST (European Cooperation in Science and Technology).

This article belongs to the Special Issue Synthesis, Characterization and Simulation of Soft Matter with EUSMI., Poly(2,5-alkylene furanoate)s are bio-based, smart, and innovative polymers that are considered the most promising materials to replace oil-based plastics. These polymers can be synthesized using ecofriendly approaches, starting from renewable sources, and result into final products with properties comparable and even better than those presented by their terephthalic counterparts. In this work, we present the molecular dynamics of four 100% bio-based poly(alkylene 2,5-furanoate)s, using broadband dielectric spectroscopy measurements that covered a wide temperature and frequency range. We unveiled complex local relaxations, characterized by the simultaneous presence of two components, which were dependent on thermal treatment. The segmental relaxation showed relaxation times and strengths depending on the glycolic subunit length, which were furthermore confirmed by high-frequency experiments in the molten region of the polymers. Our results allowed determining structure–property relations that are able to provide further understanding about the excellent barrier properties of poly(alkylene 2,5-furanoate)s. In addition, we provide results of high industrial interest during polymer processing for possible industrial applications of poly(alkylene furanoate)s., This research was funded by the European Union: EUSMI, H2020-INFRAIA-2016-1, PROJECT 731019, via proposals E171100043 and E171100040. The APC was funded by EUSMI. B.R.-H. and A.A. acknowledge funding from Basque Government (IT-1175-19). D.E.M.-T. acknowledges financial support via the postdoctoral fellowship “Juan de la Cierva–Incorporación” grant (IJCI-2017-31600, MCIU–Spain). G.G., M.S. and N.L. and A.M. acknowledge financial support via the framework COST Action FUR4Sustain, CA18220, supported by COST (European Cooperation in Science and Technology).

Novel A-B-A triblock copolymers based on poly(L-lactic acid) (PLLA) were designed with an ad hoc chemical structure to prepare micro- and nanoparticles for controlled drug delivery. A block is formed by PLLA, while central B block is a copolymeric system based on poly(butylene succinate) and poly(triethylene succinate): more specifically, two copolymers with fix composition (50:50 mol:mol) and different molecular architecture were synthesized. One of them is characterized by a block architecture, i.e. long butylene succinate and triethylene succinate sequences form the macromolecular chains, the other being on the contrary a random copolymer with short sequences. The so-obtained materials were characterized from the molecular and thermal point of view. Moreover, to investigate the effect of both chemical structure and molecular architecture of the polymers synthesized on drug release kinetics, Dexamethasone-encapsulated micro- and nanoparticles were prepared by oil-in-water miniemulsion technique. These particles were subjected to thermal and morphological characterization. After that, drug release studies were carried out, and the effect of chemical composition, sequence distribution and particle size on release profile was evaluated. (C) 2020 Elsevier Ltd. All rights reserved.

The crystallization behavior of fully biobased poly(butylene isophthalate) (PBI) has been investigated using calorimetric and microscopic techniques. PBI is an extremely slow crystallizing polymer that leads, after melt-crystallization, to the formation of lamellar crystals and rather large spherulites, due to the low nuclei density. Based upon quantitative analysis of the crystal-nucleation behavior at low temperatures near the glass transition, using Tammann&rsquo, s two-stage nuclei development method, a nucleation pathway for an acceleration of the crystallization process and for tailoring the semicrystalline morphology is provided. Low-temperature annealing close to the glass transition temperature (Tg) leads to the formation of crystal nuclei, which grow to crystals at higher temperatures, and yield a much finer spherulitic superstructure, as obtained after direct melt-crystallization. Similarly to other slowly crystallizing polymers like poly(ethylene terephthalate) or poly(l-lactic acid), low-temperature crystal-nuclei formation at a timescale of hours/days is still too slow to allow non-spherulitic crystallization. The interplay between glass relaxation and crystal nucleation at temperatures slightly below Tg is discussed.

Poly(butylene 2,6-naphthalate) (PBN) is a crystallizable linear polyester containing a rigid naphthalene unit and flexible methylene spacer in the chemical repeat unit. Polymeric materials made of PBN exhibit excellent anti-abrasion and low friction properties, superior chemical resistance, and outstanding gas barrier characteristics. Many of the properties rely on the presence of crystals and the formation of a semicrystalline morphology. To develop specific crystal structures and morphologies during cooling the melt, precise information about the melt-crystallization process is required. This review article summarizes the current knowledge about the temperature-controlled crystal polymorphism of PBN. At rather low supercooling of the melt, with decreasing crystallization temperature, β’- and α-crystals grow directly from the melt and organize in largely different spherulitic superstructures. Formation of α-crystals at high supercooling may also proceed via intermediate formation of a transient monotropic liquid crystalline structure, then yielding a non-spherulitic semicrystalline morphology. Crystallization of PBN is rather fast since its suppression requires cooling the melt at a rate higher than 6000 K·s−1. For this reason, investigation of the two-step crystallization process at low temperatures requires application of sophisticated experimental tools. These include temperature-resolved X-ray scattering techniques using fast detectors and synchrotron-based X-rays and fast scanning chip calorimetry. Fast scanning chip calorimetry allows freezing the transient liquid-crystalline structure before its conversion into α-crystals, by fast cooling to below its glass transition temperature. Subsequent analysis using polarized-light optical microscopy reveals its texture and X-ray scattering confirms the smectic arrangement of the mesogens. The combination of a large variety of experimental techniques allows obtaining a complete picture about crystallization of PBN in the entire range of melt-supercoolings down to the glass transition, including quantitative data about the crystallization kinetics, semicrystalline morphologies at the micrometer length scale, as well as nanoscale X-ray structure information.

The peculiar reactivity of catechol carbonate (CC) with amines and polyamines in both solvent and catalyst free conditions is herein described. In all the tests performed at room temperature, CC conversion reached 100% in few seconds leading to the selective formation of the corresponding 2-hydroxyphenylcarbamate. This compound is furtherly rapidly converted to the di-substituted urea by the consecutive nucleophilic attack of another amine. Noteworthy, the application of this approach can be successfully extended to the one-pot bio-amine based synthesis of polyurea as herein proposed for the first time in literature. The reaction is of general purpose for primary amines and catechol can be easily recovered by sublimation as pure crystals ready to be recycled for the synthesis of new CC. An exception is related to the reactivity of secondary amine, which leads anyway to the selective formation of substituted phenolic carbamates (e.g. 2-hydroxyphenyl diethylcarbamate), suitable as intermediates in medicinal chemistry.

Plastics remarkably contribute to marine litter, which is raising serious concerns. Currently, little is known about the fate of most plastics entering the marine environment and their potential biodegradation rate and extent under anoxic conditions. In this work, biodegradation of polyvinyl chloride (PVC) films by consortia enriched from marine samples (litter and water) was evaluated in anaerobic microcosms. After 7 months, three microcosms showed dense biofilms on plastic surfaces, gravimetric weight losses up to 11.7 ± 0.6%, marked decreases in thermal stability and average molecular weight of the polymer, suggesting microbial attack towards polymer chains. After 24 months, further three consortia showed the same abilities. Microbial communities analyzed at month 24 included taxa closely related to those previously reported as halogenated organic compounds degraders. The study is the first report on PVC biodegradation by marine anaerobic microbes and provides insights on potential biodegradation of the plastic film introduced into the sea by native microbes.

Biopolymers are gaining increasing importance as substitutes for plastics derived from fossil fuels, especially for packaging applications. In particular, furanoate-based polyesters appear as the most credible alternative due to their intriguing physic/mechanical and gas barrier properties. In this study, block copolyesters containing 2,5-furan and trans-1,4-cyclohexane moieties were synthesized by reactive blending, starting from the two parent homopolymers: poly(propylene furanoate) (PPF) and poly(propylene cyclohexanedicarboxylate) (PPCE). The whole range of molecular architectures, from long block to random copolymer with a fixed molar composition (1:1 of the two repeating units) was considered. Molecular, thermal, tensile, and gas barrier properties of the prepared materials were investigated and correlated to the copolymer structure. A strict dependence of the functional properties on the copolymers&rsquo, block length was found. In particular, short block copolymers, thanks to the introduction of more flexible cyclohexane-containing co-units, displayed high elongation at break and low elastic modulus, thus overcoming PPF&rsquo, s intrinsic rigidity. Furthermore, the exceptionally low gas permeabilities of PPF were further improved due to the concomitant action of the two rings, both capable of acting as mesogenic groups in the presence of flexible aliphatic units, and thus responsible for the formation of 1D/2D ordered domains, which in turn impart outstanding barrier properties.

In recent years there has been a growing interest in the use of proteins as biocompatible and environmentally friendly biomolecules for the design of wound healing and drug delivery systems. Keratin is a fascinating protein, obtainable from several keratinous biomasses such as wool, hair or nails, with intrinsic bioactive properties including stimulatory effects on wound repair and excellent carrier capability. In this work keratin/poly(butylene succinate) blend solutions with functional properties tunable by manipulating the polymer blending ratios were prepared by using 1,1,1,3,3,3-hexafluoroisopropanol as common solvent. Afterwards, these solutions doped with rhodamine B (RhB), were electrospun into blend mats and the drug release mechanism and kinetics as a function of blend composition was studied, in order to understand the potential of such membranes as drug delivery systems. The electrophoresis analysis carried out on keratin revealed that the solvent used does not degrade the protein. Moreover, all the blend solutions showed a non-Newtonian behavior, among which the Keratin/PBS 70/30 and 30/70 ones showed an amplified orientation ability of the polymer chains when subjected to a shear stress. Therefore, the resulting nanofibers showed thinner mean diameters and narrower diameter distributions compared to the Keratin/PBS 50/50 blend solution. The thermal stability and the mechanical properties of the blend electrospun mats improved by increasing the PBS content. Finally, the RhB release rate increased by increasing the keratin content of the mats and the drug diffused as drug-protein complex.

Fully biobased random copolymers of poly(butylene succinate) (PBS) containing different amount of Pripol 1009 moieties were synthesized by melt polycondensation. Molecular characterization confirmed the chemical structure and the random distribution of counts (NMR) and indicated that high molecular weight samples were obtained (GPC). All the polymers under study were semicrystalline, developing the typical alpha-PBS crystalline phase, the melting temperature and the crystallinity degree regularly decreasing with the increase of Pripol content. Pripol moieties determined also an improvement of polymer chain flexibility, as proved by the glass transition temperature decreasing, and of thermal stability. Polymer mechanical response was nicely tuned by changing copolymer composition, the copolymer with the highest Pripol content showing the typical behavior of thermoplastic elastomers despite its random nature. Lastly, biodegradation rate in compost also increased with the content of Pripol due to the parallel decrease of sample crystallinity degree. Surprisingly, microorganisms present in the compost preferentially attack BS comonomeric units despite their semicrystalline nature. (C) 2020 Elsevier Ltd. All rights reserved.

9 pags., 8 figs., 1 tab., 2 schs.-- sc9b04407_si_001.mp4 (75.48 MB) sc9b04407_si_002.mp4 (5.46 MB), Among the various factors that contribute to the transition from a linear to a circular economy, the identification of superpolymers with outstanding mechanical as well as barrier properties and zero environmental impact has become a mandatory issue. Such new supermaterials render recycling a concrete option for the efficient and ecofriendly management of plastic wastes. In this study, a 100% biobased polyester has been prepared by a one-pot and solvent-free synthesis, starting from 2,5-furandicarboxylic acid and 1,5-pentanediol. At first, a molecular and thermal characterization of the polymer has been conducted and then processed to prepare a compression molded film, despite its amorphous and rubbery nature at room temperature. The mechanical response was typical of elastomers, with a low elastic modulus and stress at break and high elongation at break. An instant shape recovery after breaking was observed, indicating the presence of net points. The barrier properties to O and CO were exceptional and similar to those of ethylene vinyl alcohol (EVOH) and of polymer liquid crystals. All of these unexpected and surprising properties were explained as being due to the presence of a 2D microstructure characterized by partially ordered furanic rings favored by intermolecular C-H···O bonds., Experiments at the ALBA Synchrotron have been funded by the Spanish Ministry of Science, Innovation and Universities (MSIU). This study was also partially supported by MSIU by the grant MAT2015-66443-C02-1-R.

Edible films and coatings gained renewed interest in the food packaging sector with polysaccharide and protein blending being explored as a promising strategy to improve properties of edible films. The present work studies composite edible films in different proportions of pectin (P), alginate (A) and whey Protein concentrate (WP) formulated with a simplex centroid mixture design and evaluated for physico-chemical characteristics to understand the effects of individual components on the final film performance. The studied matrices exhibited good film forming capacity, except for whey protein at a certain concentration, with thickness, elastic and optical properties correlated to the initial solution viscosity. A whey protein component in general lowered the viscosity of the initial solutions compared to that of alginate or pectin solutions. Subsequently, a whey protein component lowered the mechanical strength, as well as the affinity for water, as evidenced from an increasing contact angle. The effect of pectin was reflected in the yellowness index, whereas alginate and whey protein affected the opacity of film. Whey protein favored higher opacity, lower gas barrier values and dense structures, resulting from the polysaccharide-protein aggregates. All films displayed however good thermal stability, with degradation onset temperatures higher than 170 &deg, C.

The copolymer was obtained through chain extension of two hydroxyl-terminated prepolymers prepared by polycondensation: poly(hexamethylene furanoate) PHF–OH, and poly(triethylene furanoate) PTEF-OH. The chain extended homopolymer PHF-CE was also synthesized for sake of comparison. Molecular, structural and thermal analyses evidenced that copolymerization has an impact on solidstate properties. The presence of the two different polymer blocks allows the obtaining of a tenacious material with high melting temperature, characterized by lower elastic modulus and improved elongation at break. To evaluate the potentiality of this new material in the field of food packaging, gas permeability behaviour to oxygen, carbon dioxide and nitrogen at 23 °C was evaluated: the synthetic path adopted leads to a improvement of the outstanding gas barrier performance in the multiblock copolyester with respect to the homopolymer. Composting tests showed that the molecular architecture plays a key role in determining a faster degradation rate.

Microorganisms colonizing plastic waste material collected in composting-, landfill-, and anaerobic digestion plants were isolated to obtain novel strains maximally adapted to the degradation of plastics due to long-term contact with plastic polymers. Twenty-six bacterial strains were isolated and identified by the 16 S rRNA method, and eighteen strains of yeasts and fungi using 18 S rRNA and the internal transcribed spacer ITS sequencing of the 18 S rRNA gene. In selected strains, the ability to degrade linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), polystyrene (PS), and polyvinyl chloride (PVC) was tested in aerobic liquid-medium cultures. An oxidative, two-step pretreatment of LLDPE and LDPE using &gamma, or UV-irradiation followed by a high-temperature treatment was carried out, and the pretreated plastics were also included in the degradation experiments. The respective weight losses after biodegradation by Trichoderma hamatum were: virgin and &gamma, /T90-pretreated LLDPE (2.2 &plusmn, 1.2 and 3.9 &plusmn, 0.5%), virgin and UV/T60-pretreated LDPE (0.5 &plusmn, 0.4 and 1.3 &plusmn, 0.4%), and virgin PS (0.9 &plusmn, 0.4%). The Fourier transform infrared spectroscopy (FTIR) analysis showed that during the treatment of pretreated LLDPE, T. hamatum attacked low molecular weight LLDPE oligomers, reducing the functional groups (carbonyl C = O), which was paralleled by a slight increase of the molar mass of pretreated LLDPE and a decrease of the dispersity index, as demonstrated by gel permeation chromatography (GPC). Thermogravimetric analysis (TGA) highlighted the formation of functional groups on LLDPE due to polymer pretreatment that favored fungal attack at the polymer surface. The results provide insight into microbial consortia that spontaneously colonize the surface of plastics in various environments and their capability to attack plastic polymers.

A series of novel random copolymers of poly(propylene 1,4-cyclohexanedicarboxylate) (PPCE) containing neopentyl glycol sub-unit (P(PCExNCEy)) were synthesized and characterized in terms of molecular and solid-state properties. In addition, biodegradability studies in compost have been conducted. The copolymers displayed a high and similar thermal stability with respect to PPCE. At room temperature, all the copolymers appeared as semicrystalline materials: the main effect of copolymerization was a lowering of crystallinity degree (Xc) and a decrease of the melting temperature compared to the parent homopolymer. In particular, Wide Angle X-Ray diffraction (WAXD) measurements indicated that P(PCExNCEy) copolymers are characterized by cocrystallization, PNCE counits cocrystallizing in PPCE crystalline phase. Final properties and biodegradation rate of the materials under study were strictly dependent on copolymer composition and Xc. As a matter of fact, the elastic modulus and the elongation at break decreased and increased, respectively, as neopentyl glycol cyclohexanedicarboxylate (NCE) unit content was increased. The presence of a rigid-amorphous phase was evidenced by means of Dynamic Mechanical Thermal Analysis (DMTA) analysis in all the samples under investigation. Lastly, the biodegradation rate of P(PCExNCEy) copolymers was found to slightly increase with the increasing of NCE molar content.

Within the context of new bioplastic materials, poly(butylene succinate) (PBS) and four novel poly(butylene/thiodiethylene succinate) random copolymers (PBS-PTDGS), in sheets as well as in films, were exposed to gamma radiation, in air and in water, and their behavior along with the effect on their biodegradability was investigated. The molecular weight data obtained from gel permeation chromatography indicate that the sensibility to radiation increases with the amount of sulfur-containing co-unit (TDGS). At 200 kGy the average molecular weight of PBS film halves, while for P(BS60TDGS40) the residual molecular weight is about 20%. The calculated intermolecular crosslink Gx and scissioning Gs yields confirmed that degradation is predominant over crosslink for all the aliphatic systems. As shown by thermal analyses, gamma radiation affects the thermal properties, leading to an increased crystallinity of the systems, remarkable for PBS, and lower decomposition temperatures. Variations of crystallinity with the increasing absorbed dose were confirmed also by PALS analyses. Water contact angle measurements revealed post-irradiation wettability alterations that could positively affect polymer biodegradability. In particular, when irradiated in water at 100 kGy PBS film exhibits a water contact angle decrease of about 17%, indicating an enhanced wettability. After degradation in compost, changes in the surface morphology were observed by means of SEM and sample weight losses were determined, at different extent, according to the irradiation environment. Interestingly, after 52 days in compost PBS films, both pristine and irradiated in air at 25 kGy, showed a residual weight of about 60%, while the ones irradiated in water at 25 kGy of about 44%. Experimental data confirmed that gamma irradiation could represent a viable treatment to enhance biodegradation in compost of PBS and PBS-based copolymers.

The effect of presence of up to 30 mol% diethylene 2,6‐naphthalate (DEN) constitutional defects on the crystallization kinetics and morphology of poly(butylene 2,6‐naphthalate) (PBN) was investigated by differential scanning calorimetry, fast scanning chip calorimetry, polarized‐light optical microscopy, and wide‐angle X‐ray scattering (WAXS). The results indicate that the crystallization behavior of butylene/DEN random copolymers [P(B xDE yN)] is analogous to the PBN homopolymer: at low supercooling direct crystallization from the melt occurs, while at lower crystallization temperature/higher cooling rates, the formation of a liquid crystalline phase precedes the development of the ultimately stable crystal, confirming the validity of Ostwald's rule of stages also for random copolymers. However, the incorporation of DEN counits into the polymer chains retards both crystal and liquid‐crystal formation proportionally to the DEN content. WAXS analysis suggests the exclusion of DEN counits from PBN crystals. Thus, the lower crystallization rate in the copolymers can be associated, with the filtering of crystallizable chain segments at the crystal growth front.

Enzymatic hydrolysis of poly(1,4-butylene 2,5-thiophenedicarboxylate) (PBTF) and poly(1,4-butylene 2,5-furandicarboxylate) (PBF) by Humicola insolens (HiC) and Thermobifida cellulosilytica (Cut) cutinases is investigated. For the first time, the different depolymerization mechanisms of PBTF (endo-wise scission) and PBF (exo-wise cleavage) has been unveiled and correlated to the chemical structure of the two polyesters. Keywords: Poly(1,4-butylene 2,5-thiophenedicarboxylate) (PBTF), Poly(1,4-butylene 2,5-furandicarboxylate) (PBF), Enzymatic hydrolysis, Endo/exo chain scission, Cutinases, Polyesters degradation

none 8 no The objective of this work was to develop a versatile strategy for preparing multifunctional composite films with tunable properties. Novel conductive composites based on the combination of single walled carbon nanotubes (SWCNTs) and biodegradable poly(butylene cyclohexanedicarboxylate/diglycolate) random copolymers (P(BCEmBDGn)) are here presented. In particular, synthesized PBCE homopolymer and two copolymers containing different amounts of ether–oxygen containing co-units, P(BCE90BDG10) and P(BCE70BDG30), have been considered as matrices of SWCNTs based composites. The effect of incorporation of different amounts of SWCNTs (0.1–0.5–0.75–1 wt%) on morphological, thermal, mechanical and electrical properties was deeply investigated. The morphology of the fracture surfaces is affected by the SWCNT presence, while the increase in the SWCNT content does not provide significant microstructure modifications. The thermal properties underlined that nanotubes can act as nucleating agents, favouring the polymer crystallization process. The mechanical behavior demonstrated that the introduction of carbon nanotubes both in the case of PBCE homo - polymer and in random copolymers based formulations exerted a reinforcing effect. All composites exhibit high electrical conductivity in comparison to the neat polymers. This work demonstrates that this combinatorial approach can be used to develop materials with tunable and advanced functional properties. Fortunati E.; Gigli M.; Luzi F.; Lotti N.; Munari A.; Gazzano M.; Armentano I.; Kenny J.M. Fortunati E.; Gigli M.; Luzi F.; Lotti N.; Munari A.; Gazzano M.; Armentano I.; Kenny J.M.

Novel fully bio-based poly(lactic acid) copoly(ester-urethane)s have been successfully synthesized. The new system is composed of a series of A-B-A triblock copolymers, where A, hard block, is poly(lactic acid) and B, soft block, is an ad hoc designed random aliphatic copolyester, poly(butylene succinate/azelate), characterized by high flexibility. Triblock units are joined by hexamethylene diisocyanate, known chain extender that allows the obtaining of polymers with high molecular weights. The samples synthesized were subjected to a detailed molecular, thermal, structural and mechanical characterization. The results obtained, show that copolymerization leads to better mechanical response with respect to poly(lactic) acid homopolymer. Moreover, the presence of the soft block in the main polymer chain facilitates the process of biodegradability. Nanoparticles of selected copolymers fabricated by using the nanoprecipitation method showed rounded morphology and average hydrodynamic diameters around 180 nm. Cellular behavior was assessed using human fibroblasts in vitro assays and results showed absence of cytotoxicity and a good cellular adhesion and proliferation on all the copolymer surfaces.

Novel fully biobased aliphatic-aromatic poly(butylene 2,5-furanoate/diglycolate) random copolyesters were successfully synthesized from 2,5-furandicarboxylic acid, diglycolic acid and 1,4-butanediol through two-stage melt polycondensation using titanium tetrabutoxide and titanium tetraisopropoxide as catalysts. The synthesized polymers were characterized in terms of molecular and solid-state properties, among these, barrier properties to different gases. In addition, biodegradability studies in compost have been conducted. All the polymers showed a good thermal stability, even higher than that of the thermally stable homopolymer poly(butylene furanoate), and at room temperature appeared as semicrystalline materials. The main effect of copolymerization was a lowering, up to 60 °C, in Tm respect to the homopolymer. The dependence of Tm on composition for copolymers was well described by Baur’s equation. Diffractometric measurements indicated that only the poly(butylene furanoate) crystalline phase is present in the copolymers under investigation. Amorphous samples showed a monotonic decrement of Tg, up to 30 °C, as the content of butylene diglycolate units is increased and this can be explained on the basis of the higher flexibility induced in the polymer chain by the ether-oxygen atoms. A Wood-type equation was found to fit the Tg data of completely amorphous samples. Final properties and biodegradation rate of the materials under study were strictly dependent on the copolymer composition and the crystallinity degree. As a matter of fact, hydrophilicity regularly increased with the increasing of butylene diglycolate mol%, due to the highly electronegative ether-oxygen atoms present in the co-units (water contact angle decreased of almost 15°). The elastic modulus decreased till one order of magnitude and the elongation to break increased, up to 400%, as co-unit content was increased. Regarding the gas barrier properties, copolymerization did not imply a worsening with respect to the homopolymer. A slight increment of the gas transmission rate was recorded just for the copolymer containing the highest amount of butylene diglycolate units, as a consequence of the increasing flexibility of the macromolecular chain due to the ether-oxygen atoms. This behavior was more evident with CO2 gas test than with O2, N2 and C2H4 ones.

Bioactive scaffolds for tissue engineering call for demands on new materials which can enhance traditional biocompatibility requirements previously considered for clinical implantation. The current commercially available thermoplastic materials, such as poly(lactic acid) (PLA), poly(glycolic acid) (PGA), poly(?-caprolactone) (PCL) and their copolymers, have been used to fabricate scaffolds for regenerative medicine. However, these polymers have limitations including lacking of broadly tuning mechanical and degradable properties, and activation of specific cell-scaffold interactions, which limit their further application in tissue engineering. In the present study, electrospun scaffolds were successfully fabricated from a new class of block poly(butylene succinate)-based (PBS-based) copolyesters containing either butylene thiodiglycolate (BTDG) or butylene diglycolate (BDG) sequences. The polyesters displayed tunable mechanical properties and hydrolysis rate depending on the molecular architecture and on the kind of heteroatom introduced along the polymer backbone. To investigate their potential for skeletal regeneration, human mesenchymal stromal cells (hMSCs) were cultured on the scaffolds in basic, osteogenic and chondrogenic media. Our results demonstrated that PBS-based copolyesters containing thio-ether linkages (i.e. BTDG segments) were more favorable for chondrogenesis of hMSCs than those containing ether linkages (i.e. BDG sequences). In contrast, PBS-based copolyesters containing ether linkages showed enhanced mineralization. Therefore, these new functional scaffolds might hold potential for osteochondral tissue engineering applications.

7 pags.; 9 figs., © 2015 Elsevier Ltd. All rights reserved. Nanostructured gratings of semicrystalline poly(propylene azelate) (PPAz) have been prepared over spin-coated thin films by Nanoimprint Lithography (NIL). The structure and morphology of the gratings have been investigated by combining Atomic Force Microscopy (AFM) and Grazing Incidence X-ray Scattering at small angle (GISAXS) and wide angle (GIWAXS). The results reveal that NIL affects significantly the orientation of the crystalline lamellae. PPAz gratings are more abundant in edge-on lamellae than the reference non-printed films. We attribute this effect to the PPAz preferential crystallization as flat-on lamellae on silicon surfaces either the stamp trench walls or the substrate surface. Thus, the flat-on lamellae on the trench walls appear to be edge-on lamellae in the printed sample. These results further support NIL as an appropriate procedure in order to control polymer crystal orientation., The financial support of MINECO through MAT2012-33517 and MAT2011-23455 is gratefully acknowledged. M.S. is indebted to CSIC for the tenure of JAE-Doc fellowships and the “Fondo Social Europeo” (FSE) for co-financing the JAE program

Nowadays aliphatic polyesters have attracted considerable attention as they combine the features of biodegradability and biocompatibility with physical and chemical properties comparable with some of the most extensively used polymers (LDPE, PP, etc.). In particular, polyesters based on 1,3-propanediol (1,3-PD) have attracted increasing interest in the last few years, being 1,3-PD obtainable by renewable feedstocks[1]. Dimethyl trans-cyclohexane-1,4-dicarboxylic (DMCEDA) acid, which can also be considered a bio-based monomer, contains an aliphatic ring in the monomeric unit, whose stereochemistry strongly influences the final properties of the material [2]. A series of novel random copolymers of poly(propylene 1,4-cyclohexanedicarboxylate) (PPCE) containing neopenthyl glycol sub-unit (P(PCExNCEy)) were synthesized and their structure-dynamics relationships have been investigated by means of X-ray scattering and dielectric loss spectroscopy experiments. The subglass dynamics of the polymers as revealed by dielectric spectroscopy is characterized by the existence of two processes, γ and β in order of increasing temperature. We propose that the high frequency(lower temperature) γ-relaxation is associated to the ester oxygen linked to the aliphatic carbon of the diol subunit, whereas the low frequency(higher temperature) β-relaxation has been assigned to the carbon of the ester groups linked to the aliphatic ring.

Trabajo presentado a: 6th Meeting of the Spanish Neutron Scattering Association (SETN2012).-- Under the terms of the Creative Commons Attribution 3.0 licence., We show that the combination of dielectric relaxation with neutron spin echo and incoherent neutron backscattering measurements performed in deuterated and protonated poly(ethylene terephthalate) suggests that the intrinsic dynamics of semicrystalline polymers occurs in an homogeneous scenario, similar to that valid to describe the dynamics of totally amorphous polymers. The quasielastic neutron scattering data are satisfactorily described by a theoretical model that considers that the proton mobility follows a random jump-diffusion in a restricted environment., This work has been funded by the Spanish MINECO (MAT2009-07789, MAT2011-23455 and MAT2008-03232). A. S. also acknowledges the Spanish MINECO for financial support.

The melting transition of a model semicrystalline polymer has been detected by the microcantilever deflection as a function of temperature. Deflection measurements were done on arrays of 8-cantilevers spin coated with the semicrystalline polymer: poly (propylene azelate). The melting of the polymer has been corroborated by grazing incidence wide angle x-ray scattering experiments performed with synchrotron radiation over a single cantilever.

Novel copolyesters have been prepared by melt mixing poly(ethylene terephthalate) (PET) with an ethoxylated bisphenol S, with the aim to prepare new polyesters with increased Tg, to be used in a wider range of temperatures with respect to neat PET. No side reactions occur during the synthesis of the samples, as proved by NMR analysis. The insertion of the bisphenol S (sulfonyldiphenol) groups does not significantly alter the thermal stability of PET. The thermal analysis showed that Tm and crystallization rate of the copolymers decreased with incasing co-unit content. The Tg of the copolyesters can be increased by bisphenol S insertion, up to 40°C higher with respect to neat PET, that allows the use of amorphous PET in a wider range of applications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Poly(dithiotriethylene terephthalate) (PSSTET), poly(dithiotriethylene adipate) (PSSTEA), poly(triethylene terephthalate) (PTET) and poly(triethylene adipate) (PTEA), these two last for comparison, were synthesized and characterized in terms of chemical structure and molecular weight. The thermal behaviour was examined by thermogravimetric analysis and differential scanning calorimetry. All the polymers showed a good thermal stability, even though lower for the sulphur-containing polyesters. At room temperature they appeared as semicrystalline materials, except PTEA, which was an oil; the effect of substitution of ether oxygen atoms with sulphur ones was found to be a lowering in the Tg value, an increment of the melting temperature and an increase of the crystallization rate. The results were explained as due to the presence of flexible C–S–C bonds in the polymeric chain. Lastly, the absence of a rigid-amorphous phase was evidenced in PSSTET and PTET.

The influence of the development of crystalline structure on the segmental dynamics of the amorphous phase in poly(butylene isophthalate) (PBI) has been studied by a combination of relaxation and scattering techniques. By means of dielectric spectroscopy (DS) the dynamics of both amorphous and semicrystalline PBI samples has been observed in a wide frequency and temperature range. The evolution of the crystalline phase with time has been studied in a range of temperatures, starting from initially glassy PBI by simultaneous small and wide angle X-ray scattering (SWAXS). By using a state-of-the-art setup designed specifically for the in situ study of both DS and SWAXS simultaneously (SWD), the crystallization of initially amorphous PBI has been followed in real time from both the structural and dynamics points of view. The obtained results support a model based on two different regimes on crystallization and a heterogeneous distribution of lamellar stacks. During the first regime the primary stacks cause the apparition of a rigid amorphous phase (RAP), i.e. a phase of amorphous chains lacking segmental motion. During the second regime, however, no more RAP is observed, indicating that the new lamellae that appear during this stage are nearly individual and not forming lamella stacks. © 2005 Elsevier Ltd. All rights reserved., MCYT (grant FPA2001-2139) Spain, and Marie Curie Reintegration Grant Program of the European Community (ERG 505674). Integrated Infrastructure Initiative ‘Integrating Activity on Synchrotron and Free Electron Laser Science’ of the European CommunityResearch Infrastructure Action under the FP6 ‘Structuring the European Research Area’. MCYT Ramón y Cajal contract