Mechanical and Thermal Transport Properties of PMMA/PC and PMMA/PS Blends

The present study deals with some results on mechanical and thermal transport properties of PMMA/PC and PMMA/PS polymer blends prepared by solution casting method at concentrations (0, 25, 50, 75, 100 wt%). Dynamic mechanical Analyser (DMA) and Transient Plane Source (TPS) technique have been used to measure the mechanical properties such as Young's modulus, toughness, tensile strength, elongation at break and the thermal transport properties like thermal conductivity and thermal diffusivity of PMMA/PC and PMMA/PS blends, respectively, at room as well as elevated temperatures. Also the glass transition temperature (T-g) is determined with the help of DMA of these blended samples. The results show that the mechanical properties of PMMA/PC blends have improved significantly with the increase of PC content in PMMA polymer whereas PMMA/PS blend shows a decreased values of mechanical properties as compared to pure polymers. The Tan delta result shows a single glass transition for PMMA/PC blend which indicates a good miscibility of the blend, while PMMA/PS blend shows a double glass transition indicating the immiscibility of this blend. Similar behavior has also been exhibited in thermal transport properties. The thermal conductivity of 50PMMA/50PC blend shows an increasing behavior upto the glass transition temperature (130 degrees C) and then decreased with further increase of temperature. In case of immiscible 50PMMA/50PS blend, the values of thermal conductivity shows two maxima corresponding to two glass transition temperatures (88.4 degrees C and 103.0 degrees C) obtained. Similar trend has also been observed for thermal diffusivity measurements. For amorphous polymers, phonon can be considered as the chief heat carriers and the observed variation of thermal transport properties with temperature is explained on the basis of structural changes in the samples and mean free path of phonons.