We introduce poly (ethylene glycol) (PEG) as a second component to modify PHB. The incorporation of PEG into a PHB matrix can improve the hydrophilicity, flexibility and degradation rate.

PHB copolymers are preferred for general purposes as the degradation rate of PHB homopolymer is high at its normal melt processing temperature.

The PHB homopolymer is a stiff and rather brittle polymer of high crystallinity, whose mechanical properties are not unlike those of polystyrene, though it is less brittle.