DIELECTRIC INVESTIGATION OF THE MOLECULAR-DYNAMICS IN BLENDS - POLYMERS WITH SIMILAR MOLECULAR ARCHITECTURE (TMPC PC BLEND)/

Broad band dielectric spectroscopy was used in the investigation of th e molecular dynamics and compatibility of tetramethyl polycarbonate/po lycarbonate (TMPC/PC) blends. Frequency scan measurements in the range 10(-2)-10(-5) Hz were carried out in the temperature range 50-220 deg rees C for several blends with different compositions, namely, 0, 12.5 , 25, 50, 75, 87.5 and 100 wt% of TMPC. The results obtained show that these two polymers are ideally compatible over the entire composition range. The blends reveal only one common glass process. The dielectri c relaxation strength and the common glass transition temperature, T-g , were found to vary linearly with composition. Moreover, it was found , surprisingly, that blending has no effect on the distribution of rel axation times of the common glass process of the blends. Furthermore, neither the kinetics (relaxation frequency at a certain temperature) n or the distribution of relaxation times of the local process were infl uenced by blending. It is concluded that the polymeric chains of the d ifferent components are not miscible on a segmental level although the blend exhibits only one glass transition temperature.