Flow properties of natural rubber composites filled with defatted soy flour

PMSE 280

Lei Jong, lei.jong@ars.usda.gov, National Center for Agricultural Utilization Research, Department of Agriculture, 1815 N. University St., Peoria, IL 61604 and Jeffrey A. Byars, jeffrey.byars@ars.usda.gov, Cereal Products and Food Science Research Unit, USDA, 1815 N University St, Peoria, IL 61604.
Previously, defatted soy flour (DSF) in a styrene-butadiene matrix has been shown to have a significant reinforcement effect. In this study, the objective is to investigate the flow properties of composites in natural rubber to understand their processing characteristics. Composites with 10 to 30 wt% DSF and carbon black (CB) were prepared by freeze drying and compression molding. A capillary rheometer was used to measure the viscosity of the composites at temperatures from 90 °C to 150 °C and at shear rates from 5 to 1000 s-1. Both rubber and composites are non-Newtonian pseudoplastic fluids, and CB filled composites had higher viscosities than DSF composites. The viscosity of a 30% DSF filled composite is less temperature dependent than that of natural rubber matrix. Dynamic mechanical measurements also showed a reinforcement effect for both composites, with greater reinforcement for CB at a given concentration.