Crystallization behavior and its influence on the mechanical properties of a thermoplastic elastomer produced by Pseudomonas oleovorans

The crystallization kinetics of poly(β-hydroxyoctanoate) (PHO), a bacterially produced copolyester containing mostly β-hydroxyoctanoate repeating units was studied. The crystallization rate reached a maximum at 0-5°C. The equilibrium melting point was determined to be approximately 68°C. The long-term crystallization study on PHO crystallized from the melt at -20, +5, and +20°C revealed that stable but different levels of crystallinity were reached after 3-7 weeks. The melting endotherm peak continued to change shape for up to 19 weeks. The thermal history greatly affected the mechanical properties of the polymer