Abstract
Time-Temperature-Torque plot during mixing of PS and DCP revealed that the reaction was endothermic and torque reduced with increasing temperature. The activation energies increased from 50 to 90 rpm. After mixing MFI increased and intrinsic viscosity of PS dropped largely with rotor speed; i.e. from 4.7 to about 30 g/10min and 0.664 to about 0.4 dl/g corresponded to MW of 4.08 x 10-7 to about 2.0 x 10-7. This clearly suggests that DCP is effective to cause chain scission to PS. However, the intense of chain scission reaction with rotor speed was obvious at 150°C and insignificant at 180°C. When adding NR into the reactive PS, torque increased and mixing temperature was raised. MFI of the blend obtained at mixing temperature 150°C was lower while at 180°C was higher than that of pure styrene. Moreover, the more reduced MFI was found with higher toluene-insoluble content which consisted of both PS and NR. Insoluble part was not found in the blend produced at 180°C. This suggests that high temperature mixing is not as effective as at low processing temperature to enhance compatibility of the blend. This work reveals a possible route of making in-situ compatibilized blends which need to be developed further for better properties.
