Mechanical properties of heterophase polymer blends of cryogenically fractured soy flour composite filler and poly (styrene–butadiene)

Abstract

Reinforcement effect of cryogenically fractured soy flour composite filler in soft polymer was investigated in this study. Polymer composites were prepared by melt-mixing polymer and soy flour composite fillers in an internal mixer. Soy flour composite fillers were prepared by blending aqueous soy flour dispersion and styrene–butadiene rubber latex to form a mixture, which was then dried and cryogenically ground into powders. Upon cross-linking, the heterophase composite filler was integrated into rubber polymer and exhibited enhanced mechanical properties. Tensile strength, elongation, Young’s modulus, toughness, and tear resistance of the heterophase polymer composites were better than those of the polymer matrix. The composites reinforced by the composite fillers prepared with different polymer matrices showed that the composite filler prepared with styrene–butadiene instead of carboxylated styrene–butadiene matrix produced composites with greater elongation ratio and toughness but smaller Young’s modulus. The study of elongation rate showed that the soy flour composite fillers produced the composites with useful tensile strength, elongation ratio, and toughness at 500 mm/min strain rate. The study also showed that the effect of soy flour/polymer ratio of the composite fillers on the composite mechanical properties was small.