مرکز منطقه ای اطلاع رساني علوم و فناوري -

چكيده لاتين :

Some bimodal molecular weight distributed polystyrene samples were produced through blending the products of the free radical polymerization processes of the two parallel reactors. The two types of prepared low molecular weight polystyrenes (Mn = 40000 and Mn = 79000) at 5, 10, 15, and 20 %wt were blended with high molecular weight polystyrene (Mn = 211000), respectively. The physical and mechanical properties of these polymer blends were investigated by measuring the amount and molecular weight effects of the low molecular weight fractions on the final molecular weight distribution (MWD) and melt flow index (MFI) of the polystyrene blended samples. The results showed that the final MWD and MFI were significantly affected by the number average molecular weight and weight ratio of the low molecular weight fractions in the polystyrene blends. Furthermore, dynamic mechanical analysis (DMA) properties were determined experimentally. It was observed from DMA results that glass transition temperature (T) shows positive deviation at the low g molecular weight fraction of 5 %wt in the polystyrene blends.