STUDY OF GLASS TRANSITION TEMPERATURE OF PMMA AND CdS-PMMA COMPOSITE

The present study investigates the effect of dispersed CdS on the αand βrelaxation processes of Poly (methyl methacrylate) (PMMA). Dynamic Mechanical Analyser (DMA) have been employed at fixed frequency 1Hz at temperatures from –80 °C to 150 °C to study the dynamics of films of thickness ~ 0.05 mm of PMMA and CdS-PMMA composite. Amorphous PMMA polymer exhibits two relaxation processes. A primary (glass, or α-) relaxation process commonly referred as glass transition or α-relaxation process and a low-temperature relaxation process associated with the hindered rotation of the side group usually referred to as the β-relaxation process. CdS dispersed PMMA composite also shows α and β relaxation process and are observed at higher values of temperature as compared to pure PMMA. The higher values of glass transition temperatures are attributed to the more rigid structure of the CdSPMMA system over the pure PMMA.