Blending and reactive extrusion of polyhydroxyalkanoates and novel aliphatic polyester additives

Polyhydroxyalkanoates are a class of biodegradable polyester, typically produced by fermentation, that could be a viable replacement to some petroleum-based plastics. This polymer is attractive to research because it is biodegradable, biocompatible, and does not form any microplastics which are harmful to both human health and the environment. PHAs show much promise, but have several factors to overcome including cost, availability, slow nucleation, poor mechanical properties, and aging which decreases PHAs flexibility over time. In this study, the latter two issues are focused on, as several biobased aliphatic polyesters are evaluated as additives to polyhydroxyalkanoates (PHAs) with the goal of increasing flexibility and preventing secondary crystallization. Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) with 6% and 8% hexanoate are the two PHAs utilized in this project. Blending and reactive extrusion of these PHAs and additives include polylactide, peroxide radical initiator, and novel aliphatic copolyesters synthesized by polycondensation is explored.