Mechanical properties and higher order structures of the bacterial polyester highly oriented films

Abstract

Bacterial poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)(PHBH) highly oriented films were prepared by the combination of roll and uniaxial drawing processes. Compression molded films, which is rather brittle, turned to be ductile after roll drawing up to x 2, and the films were further uniaxially drawn to a draw ratio as high as 1000 %. The PHBH film with the tensile strength of 178 MPa and the modulus of 1.4 GPa were obtained. The roll drawn PHB film showed a slight crystalline orientation of α-form. The orientation advanced with uniaxial draw ratio and the formation of β-form crystal was observed. Relations among the processing conditions, higher order structures and mechanical properties were investigated using wide-angle X-ray diffraction, differential scanning calorimetry, and tensile measurements.