Effects of different biopolymers and additives on mechanical and barrier properties of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) blend films

Abstract

Bio-based materials could offer solutions to the problems of petroleum-derived material usage and waste management. By taking into consideration this fact, the aim of this study was to create alternative product recipes for flexible packaging with the use of biodegradable polymers in line with sustainable packaging targets. In this study, the exit point was to prepare polybutylene adipate terephthalate (PBAT) and polyhydroxyalkanoate (PHA)-based bioblends with poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) by solution casting method in order to create biocomposite combination for flexible packaging with improved properties. Hydroxypropyl methylcellulose (HPMC) additive was used to enhance barrier properties. Thermal, mechanical, optical properties, oxygen permeability, water vapor transmission rate, and morphological features of the resultant biocomposites were characterized. First of all, it was seen that the elongation at break and tensile strength properties of single biopolymers can be combined in binary structures. Then, by establishing triple blend structures, biocomposite films with improved properties were obtained. In addition, the effects of alternative polybutylene succinate (PBS) and polylactic acid (PLA) biopolymers to PBAT biopolymer in triple bioblends were examined. As a result of the studies it was found that the PHBV/PBAT/PHA structure could be developed with functional additives in order to reach the best flexible packaging formula. It was found that the oxygene transmission rate (OTR) value was improved compared to PE with PHA, PHBV and HPMC additives, decreased to 29 cc/m2.day with PBS and 14 cc/m(2).day with PLA added to the structure.