PHYSICAL PROPERTIES OF VINYLPOLYMERS COPOLYMERIZED WITH SERICIN IN WASTE WATER FROM SILK PROCESSING

Abstract

A typical vinyl monomers, such as methyl methacrylate (MMA), styrene (St), methacrylic acid (MA) and vinyl acetate (VAc) were copolymerized with sericin dispersed in waste water, which was obtained in the separation of fibroin from raw silk thread. The glass transition temperatures of St/sericin and MMA/sericin copolymers decreased with increasing sericin content. The Young's modulus and absorption energy at break, calculated from stress-strain curves of films changed as a function of sericin content. The value of tensile strength of MMA/sericin copolymer showed the maximum at around 0.15 sericin content. The microcrazing structure was observed on the fracture surface of the copolymers having the maximum tensile strength, by both scanning electron and polarized light microscopies. Ductile properties of copolymers were thought to be caused by the small amount of sericin constituent, when mechanical stress was concentrated and absorbed.