Ainara Sangroniz

Designing biodegradable polymers that combine high performance with controlled end-of-life degradation remains a key challenge in sustainable materials science. Here, we show how isodimorphic crystallization enables control of mechanical performance, melt viscoelasticity, and degradation in semicrystalline copolyesters. High-molecular-weight poly(dodecamethylene succinate-ran-ε-caprolactone) (DSxCLy) random copolymers were successfully synthesized via an optimized, solvent-free route, preserving a random microstructure and isodimorphic crystallization across the full composition range. This behavior enables precise tuning of crystallinity and morphology through composition, leading to high ductility (elongation at break >1000%), optical transparency, noteworthy barrier performance, and melt strain hardening, which enhances adhesive performance. Hydrolytic degradation studies reveal composition-dependent kinetics, with degradation rates correlating with crystallinity and morphology. These results suggest that isodimorphic copolymers can be tuned by varying composition and molecular weight to develop structure-property-degradation relationships in semicrystalline (bio)copolymers, offering a basis for developing potentially sustainable materials with balanced functional performance and controlled end-of-life behavior.

Food packaging films containing biobased fillers can offer improved functional properties while meeting current environmental sustainability requirements for a circular and sustainable society. In this work, biocomposites based on chitin nanofibers and PVA have been developed in order to improve the mechanical performance and water barrier properties, performing for the first time a life cycle assessment. The biocolloids employed are chitin nanofibrils (ChNFs) from fungi, an underutilized renewable carbon feedstock in packaging, which are more environmentally friendly than conventional ChNFs obtained from crustaceans. Free-standing nanocomposite films are obtained by solvent casting, using water as the sole solvent. The incorporation of ChNFs results in a mechanical reinforcing effect of PVA that increases the Young modulus. The water vapor barrier character of PVA is significantly enhanced by the presence of ChNFs, which is decreased by 70% upon the incorporation of 10% ChNFs, overcoming one of the most significant drawbacks of PVA. The nanocomposites maintain an excellent oxygen barrier character under high relative humidity. Life cycle assessment (LCA) reveals a global warming potential of 5.0–5.2 kg·CO2 equiv·kg–1 for PVA/ChNFs films, demonstrating clear environmental benefits of the incorporation of ChNFs when considering the final properties. Overall, this work highlights the potential of fungal ChNFs to improve the mechanical properties and significantly improve the water barrier character of PVA, overcoming one of the limitations of this material in a sustainable way, as demonstrated by LCA.

A real-world laboratory accident highlights underestimated dermal risks posed by reactive isocyanates. First-aid actions and essential safety insights are shared to reinforce best laboratory safety practices.

Lactide-valerolactone copolymers have potential application in the packaging sector. Different copolymers were synthesized, and the kinetics of the copolymerization reactions and the microstructure of the copolymers were analysed. Lactide showed higher reactivity than valerolactone which leads to composition drift through the reaction. Thermal, mechanical and barrier properties of the selected copolymers were studied. Overall, the incorporation of valerolactone results in copolymers with higher ductility than poly(lactide) with intermediate water and oxygen permeability which makes these materials appropriate candidates for use in the packaging sector.

Poly(hydroxy acids) derived from the self-condensation of hydroxy acid are biodegradable and can be fully recycled in a Circular Economy approach.

In order to make poly(lactide) (PLA) suitable for food packaging applications, its toughness must be improved. In this work, the plasticization effectiveness of a low‐molecular‐weight plasticizer and a triblock copolymer are analyzed. For this purpose, PLA is blended with poly(ethylene glycol) (PEG) and poly(lactide‐ethylene glycol‐lactide) (LA‐EG‐LA) triblock copolymer. The obtained results show that copolymers are more effective, reducing the glass transition temperature of PLA. Although PLA/PEG blends have been widely studied in the literature, the barrier character has not been analyzed, which is of paramount importance for packaging applications. Therefore, the permeability to carbon dioxide, oxygen, and water vapor of PLA/PEG blends has been characterized observing an increase with the incorporation of PEG, which is the expected behavior. However, the incorporation of LA‐EG‐LA copolymers leads to permeability values that are slightly higher, similar, or even lower than PLA. Furthermore, the free volume of the samples has been analyzed in order to gain a deeper insight on the factors affecting the transport properties. Overall, this works aims to provide a better understanding towards the design of biodegradable packaging with improved properties that could be also extended to other biodegradable polymers. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48868.

Plastics have become indispensable in modern life and the material of choice in packaging applications, but they have also caused increasing plastic waste accumulation in oceans and landfills. Although there have been continuous efforts to develop biodegradable plastics, the mechanical and/or transport properties of these materials still need to be significantly improved to be suitable for replacing conventional plastic packaging materials. Here we report a class of biorenewable and degradable plastics, based on copolymers of γ-butyrolactone and its ring-fused derivative, with competitive permeability and elongation at break compared to commodity polymers and superior mechanical and transport properties to those of most promising biobased plastics. Importantly, these materials are designed with full chemical recyclability built into their performance with desired mechanical and barrier properties, thus representing a circular economy approach to plastic packaging materials.