Biodegradable Polymer Blends: Studies on Performance Control through Droplet to Co-continuous Morphology

This is the first-ever scientific report on melt blending of two tough home-compostable bioplastics, namely, bio-based poly(butylene succinate-co-adipate) (BioPBSA) and poly(butylene adipate-co-terephthalate) (PBAT). The micrographs from scanning electron microscopy showed that the morphology changed from a droplet-matrix to a co-continuous one as the PBAT concentration was increased in blends. Rheological studies revealed an increase in viscosity and storage modulus of some blends, specifically, the one with 30 wt % of PBAT, as compared to neat biopolymers, as evidence of compatibilization between two bioplastics. The crystallization temperature of PBAT reduced in the presence of BioPBSA, but the presence of a solid PBAT phase did not affect the crystallization of BioPBSA significantly. PBAT showed high capability to enhance the %elongation at break of BioPBSA except in blends with an equal concentration of biopolymers. The appropriate blends having balanced melt elasticity and %elongation show promise for flexible packaging uses as sustainable alternatives to their non-biodegradable plastics such as polyethylene.