Effect of different copolymers (hydrogenated and non-hydrogenated, with different molecular weights and different content of styrene] in the compatibilization of PS+PP(80+20) polyblend

We have studied the effect of the addition of different compositions of sev eral styrene / butadiene / styrene (SBS) triblock copolymers, hydrogenated and non-hydrogenated, with different molecular weights and different conten t of styrene, on the PS + PIP (80+20) polyblend. We have determined the inf luence of these parameters on thermal and mechanical properties as well as on the observed morphology. As the composition of the hydrogenated copolyme r or the copolymer with a similar content of styrene and butadiene was incr eased, the dispersion of particles increased, lowering remarkably their siz e and producing this way a better interfacial adhesion in the blend. Exclud ing the copolymer with similar content of styrene and butadiene in its stru cture, the rest of the copolymers show a strong tendency to form micelles o r mesophases in the matrix as the amount of copolymer increases, improving some mechanical properties such as impact strength but deteriorating others like the yield and break stresses. On the other hand, the presence of comp atibilizers, at any composition, does not have any effect on the thermal pa rameters of the blend. Nevertheless, the presence of PS, amorphous and the majority component in the blend, affects the crystallization process of PP, enhancing in a wide temperature range (from 125 degreesC to 40 degreesC) i ts crystallization process.