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World plastic production reached 368 million tons in 2019 and about 40% of them is used for the packaging sector. Recently, the problems related to the depletion of oil, from which the 98% of plastics derives, and to the plastic pollution, mainly due to not biodegradable materials, have driven research, industrial and end-user interests towards sustainable plastic products, derived from biomass and responding to the principles of recovery, reuse and recycling. In particular, the creation of a new packaging for the food sector, especially if intended for the packaging of organic food products, cannot ignore the logic of a sustainable development, as also requested by consumers who are increasingly attentive to concepts such as waste reduction, circularity of materials, food safety. In this perspective, the research activity of the AgriCo.Pack project, funded by the Emilia Romagna Region, concerns the development of a packaging material for fresh fruit and vegetables, that is biobased and biodegradable / compostable and characterized by good performances. In particular, the new packaging is obtained by using a bio-based biodegradable polymer as the matrix and a high amount of fillers derived by agricultural production waste. The fillers are chosen according to their seasonality and availability and properly pre-treated, in order to improve their affinity with the polymeric matrix. The objective of the work is to produce polymeric bio-composites that can replace, in terms of performances and costs, materials derived from non-renewable and non-biodegradable sources. The project covers the full value chain, starting from agricultural companies, for the supply of vegetable waste, to research centers and companies interested in the development of the new packaging, designed also according to LCA analysis, to final end-users that will use a traceability system of the product.

Biocomposites composed of biodegradable polymer, as matrix material, and natural fibers, as reinforcing material, have attracted much attention from the environmental viewpoint and their advantages such as high strength & stiffness, low cost, and biodegradable properties [1-3]. The lack of good interfacial adhesion between natural fibers and matrix, low melting point, and water sensitivity make the use of natural fiber-reinforced composites less attractive. Various green methods have been explored in order to improve the compatibility between hydrophilic natural fibers and hydrophobic polymer matrices among which enzyme digestions [4]. Enzyme catalyzed reactions are highly specific and result in the separation of fibers from their non-fiber components [5]. Rice fibers can also be considered as important potential reinforcing filler for thermoplastic composite because of its lignocellulosic characteristics and the objective of this study is to investigate the reinforcing potential of original and enzymatically modified rice endosperm fibers. Rice endosperm fibers were biochemically characterized and enzymatically treated with Celluclast. Original and enzymatically treated rice fibers were characterized in order to know their surface morphology, thermal stability and crystallinity. Biocomposites were prepared by reinforcing poly(butylene succinate) (PBS) with original and enzymatic treated rice endosperm fibers (10, 20 and 30 wt%) by melt mixing at 160°C. Synthesized composites were subjected for water uptake test to investigate the resistance against water absorption. Thermal and mechanical characterization of all biocomposites was carried out in order to verify the effect of the dispersion of fibers inside the polymeric matrix. Analysis shows that rice fibers and PBS degrade in a single step, at different temperatures. Moreover, enzymatically treated fibers are slightly more stable than the original ones. The thermal properties of the composites do not vary with respect to those of PBS. Therefore, the crystalline structure of the polymeric matrix is not disturbed by the presence of fibers also when present in a large amount. Finally from tensile and flexural analysis, it has been observed that reinforcement of rice endosperm fibers have a notable effect on the mechanical performances of the composites. A significant increment of tensile and flexural properties is induced by both kinds of fibers, revealing a general reinforcement of the matrix in all the samples.

Novel bio-based and biodegradable electrospun membranes, containing bactericidal ricinoleic acid (RA) units either by copolymerization with butylene succinate (BS) units or by blending PRA and PBS homopolymers, are characterized in their chemical, thermal, mechanical and surface properties. In the blends E. coli and S. aureus mortality rate increases with PRA amount, while the copolymer shows lower bactericidal activity compared to the blend with similar composition. XPS demonstrates that in the blends an enrichment of RA units at the fiber surface occurs during electrospinning due to phase separation, while in the copolymer RA units are homogeneously dispersed along fiber cross-section.

Development of antibacterial electrospun non-woven meshes is of critical importance in several areas such as healthcare products, food packaging, water and air filtration. In this work a novel biocidal polymer, which results active against Escherichia coli and Staphylococcus aureus, was synthesized starting from the biobased ricinoleic acid monomer (RA) and processed through electrospinning in combination with a biodegradable polymer poly(butylene succinate) (PBS), through a blending approach. The optimization of electrospinning process parameters allowed fabrication of defect-free nanofibers with uniform fiber diameter distribution. The chemical, physical and mechanical properties of the obtained non woven meshes were characterized and related to mesh structure and composition. The electrospun constructs were microbiologically evaluated and antibacterials tests confirmed their high biocidal efficacy. Mortality rate of E.Coli and S.Aureus was very high and it increased with the amount of PRA in the blends. Notably, the antimicrobial performances of the meshes were retained after 3 cycles of incubation with cell bacterial suspension. The obtained biobased and biodegradable antibacterial electrospun meshes can find useful application in several sectors.