COMPARATIVE STUDY OF PS-LDPE BLENDS WITH SBR ADDITION AS COMPATIBLIZER BY TWO STEP CROSSLINKING PROCESS

Abstract

In this research Polystyrene and Low Density Polyethylene were blended in fixed ratio PS/LDPE (80/20) with the Synthetic styrene butadiene rubber (SBR) in different proportions PS/LDPE/SBR (80/20/2.5), PS/LDPE/SBR (80/20/5), PS/LDPE/SBR (80/20/10), PS/LDPE/SBR (80/20/15). The same is blended with the peroxide by double cross linking method PS/LDPE/SBR/peroxide (80/20/2.5 + 0.05%), PS/LDPE/SBR/ peroxide (80/20/5 + 0.05 %), PS/ LDPE/ SBR/ peroxide (80/20/10+ 0.05 %), PS/LDPE/SBR/peroxide (80/20/15+ 0.05 %). In this mixing a new method is studied to compatibilize the polymer blends of PS- Polystyrene and LDPE- Low density Polyethylene in the presence of styrene butadiene rubber (SBR). SBR is first crosslinked partially by acute quantity of peroxide in a mixer at 165OC. Then the crosslinked SBR is melted-Blended in the brabender mixer of PS/LDPE having ration 80/20 respectively for another 10 min. this process is called as two step crosslinking process. In the final step of mixing of polymers, the free radicals left in the PE reacts with SBR. The crosslinking that occurs between the polymer blend PS/LDPE and high quantity of SBR has not good effect on the properties of the blends i.e mechanical including other physical/mechanical properties like impact strength, tensile strength, and yield point, elongation at break, hardness and melt flow index. However, the lower amount of SBR enhance all the properties. The scanning electron microscopic results indicate that the adhesion between the inter-facials in decrease event the domain sizes have not changed enough when compared with the non-crosslinking structure. The fracture analysis is done by SEM. This twostep crosslinking process can be used on different blended system with minimum one component and at least one compatiblizer that could be cross linked.