Obtention and characterization of PLA/PHBV thin sheets by solvent casting and extrusion with application in food packaging.

Considering the increasingly notorious environmental implications caused by plastic waste, sustainable alternatives are needed. Thus, biodegradable polymers are presented as a concrete alternative within the food packaging sector, where their storage, transport and marketing involve large volumes of plastic waste. Therefore, in this study, PHBV/PLA thin sheets were developed by extrusion and solvent casting as a first stage in the search for biodegradable plastic sheeting to replace non-biodegradable common materials such as polypropylene (PP) in food packaging. Although PHBV (poly 3-hydroxy butyrate-co-3-hydroxy valerate, the main polymer in the formulation) has excellent crystallinity, barrier properties and biodegradability, unfortunately, its thermal instability and high rigidity create difficulties in its processing. Thus, PLA gives the PHBV/PLA mixture greater plasticity and thermal resistance. Consequently, PHBV/PLA thin sheets were obtained by solvent casting and extrusion at four proportions: 50/50, 60/40, 80/20 and 100/0 (%w/w). Since most research on films is done by the solvent-cast method, considering the ease of this method, it is interesting to study and compare the physicochemical and mechanical properties of this method with another that allows easy scaling, such as extrusion. Therefore, thin sheets obtained by the two methodologies were characterized by transmittance, stress–strain, water absorption, water vapour permeability and hydrophobicity tests. The results show that the extruded thin sheets have better mechanical properties than solvent-casted sheets. On the other hand, of the formulations studied, PHBV/PLA 50/50 presented the physicochemical and mechanical properties closest to PP. [ABSTRACT FROM AUTHOR]