A Polymethylvinylsiloxane/Low Density Polyethylene Blending Melt: Dynamic Rheological Behavior and Relaxation Time

The dynamic rheological behavior of a polymethylvinylsiloxane (PMVS)/ low density polyethylene (LDPE) blending melts at 150,180 and 210 ℃ is investigated by small amplitude oscillatory shear on a rotational rheometer. LDPE has higher viscosity than PMVS at three temperatures, which affects the morphology and rheological response of the blends. The LDPE-rich blends have smaller dispersed droplets and longer relaxation time than the PMVS-rich blends. Higher temperature means less viscosity as well as dynamic modulus difference between the LDPE-rich blend and the PMVS-rich blend. Increasing temperature fastens relaxation of polymer samples thus relaxation time at higher temperature is shorter than that at low temperature. Phase separation can be shown at some weight ratio of PMVS/LDPE through the failure of time-temperature superposition principle and double peaks of relaxation time including the form relaxation time peak due to relaxation of dispersed droplets.