Study on the Mechanism of the Formation and Evolution of Phase Structure in PP/PcBR Blends

Abstract

Phase dispersion theory was proposed to study the dynamic process of polymer blending with the help of mineral processing theory. Two constants, dispersion coefficient n and process coefficient b, were calculated for the early dispersion stage to describe the varying velocity of the dispersed phase dimension. In this dispersion theory, the phase dimension of binary blends of polypropylene with poly(cisbutadiene) rubber linearly increased with blending time in the early stage on a double logarithmic scale, which suggested that phase dispersion theory was applicable to the study of polymer blending dynamics. In this study, the influence of the processing conditions, that is, composition, temperature, and shear rate, on the two constants of n and b was also studied. The results showed that n and b decreased with increasing dispersed phase, and reached a minimum when the shear rate was 60 rpm. The dispersion coefficient n first decreased with increasing temperature, reached a minimum when the temperature was 2008C, and then increased with a further increase in temperature, but there was no apparent influence of temperature on the process coefficient b. The coinfluence of blending temperature and shear rate on the dispersion coefficient n showed that the smaller the content of the dispersed phase, the more sensitive the decreasing rate of phase dimension was to the temperature and shear rate.