Blends of syndiotactic polystyrene with SBS triblock copolymers

Blending of polystyrene-block-polybutadiene-block-polystyrene (SBS) tribloc k copolymers with syndiotactic polystyrene (PSsyn) has been performed in a Brabender mixer above the glass transition temperature of the triblock copo lymer but below the melting point of PSsyn. The presence of a large excess of amorphous SBS (at least 70 wt.-%) as well as of the amorphous PSsyn phas e (about 60 wt.-%, also above its T-g) allowed the easy mixing of the compo nents. In contrast, the presence of unmelted PSsyn crystallites affects bot h the final morphology of the blend as well as its dynamic behavior, Indeed according, to the dynamic thermomechanical analysis (DMTA), data it is pos sible to suggest that such solid particles act to reinforce the overall ble nd structure (as in composite materials filled with inorganic solid particl es). Similar behavior is also observed for the SBS copolymer alone below th e T-g of the styrene blocks T-g (PS). This conclusion is supported by both the compatibility of the conclusion is supported by both blends, and the,th ermal and dynamic. thermomechanical behavior at T > T-g (PS) as investigate d by means of Differential Scanning Calorimetry (DSC), Scanning Electron Mi croscopy (SEM) and DMTA. The results obtained are tentatively compared with those of similar blends obtained fron toluene solution.