Morphology and crystallization behaviour of polyhydroxyalkanoates-based blends and composites: A review

Abstract

Polyhydroxyalkanoates (PHAs) have emerged as an alternative to petrochemical-based plastics in recent decades. They are biodegradable linear polyesters that are mainly produced from microorganisms. They are also biocompatible and non-toxic, making them great candidates in medical and pharmaceutical applications such as drug delivery. The PHA family includes a variety of homo and co-polymers with a wide window of properties. Despite promising properties, several drawbacks are associated with PHAs, i.e. brittleness, slow nucleation process, thermal instability, and the deterioration of mechanical properties over time. Thus, most PHAs need modifications. Major approaches in modifying PHAs include blending with other materials and the inclusion of additives/reinforcements to produce PHA-based blends and (nano)composites. Understanding the morphology and crystallization behaviour of PHA-based blends and composites is crucial to control their processing and final properties. Here, the morphology and crystallization of PHA-based blends and composites will be reviewed and discussed while focusing on what has been left behind unaddressed and what has been achieved in the last decade. Finally, the new challenges, emerging tendencies and opportunities will be discussed.