Studies on Thermomechanical Characteristics of Poly(Methyl Methacrylate) and Ethylene-Methyl Acrylate Copolymer Blends

Blends of poly(methyl methacrylate) (PMMA) with ethylene - methyl acrylate (EMA) copolymers of different compositions, viz. 95/05, 90/10, 85/15 and 80/20 wt.% were prepared by a melt mixing technique using a twin-screw extruder. The blends were characterized by thermo-analytical methods, viz. differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). The TGA of PMMA/EMA blends show that thermal degradation takes place in two steps and the temperature of the decomposition rate maximum is proportional to the compositions of the blends. The DSC studies reveal two glass-transition temperatures (T g ) for all the blends corresponding to their individual components which indicates that the blends are incompatible. The DMA thermograms exhibit two steps in the dynamic modulus-temperature curves for higher EMA content, which is characteristic of immiscible polymers in a two phase system.