“…In fact, by enhancing fraction of hydroxyvalerate (HV), the copolymer becomes tougher (increased impact strength) and more flexible (reduced Young's modulus), with decreased tensile strength 59,72,[80][81][82] . As a rule, disadvantages of PHBV are low elongation at break, slow crystallization rate, and therefore difficult processing 63,[83][84] . Among PHAs, copolymers of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate), PHBHx, with low 3HHx residue are identified as one of the most useful members (if compared to PHB) due to its suitable mechanical properties for application as flexible films 85 .…”