Crystallinity polyhydroxyalkanoate copolymers

The simplest of the family of polyhydroxyalkanoate (PHA) biopolymers is poly-R-3-hydroxybutyrate or PHB. This polymer was first discovered in 1925 by Lemoigne and was initially described as a lipid inclusion in the bacterium Bacillus megaterium. The technical challenges for PHA are its narrow processing window and high brittleness. To overcome those problems, it is usual to make the copolymer with valerate resulting in PHBV that exhibit reduced crystallinity. 

Moving from the Cj and C2 sidechain polyhydroxyalkanoates to longer sidechains leads to a progressive change in the crystallinity and mechanical properties of the resulting copolymers. 

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