STEREOCOMPLEX FORMATION IN POLYBUTADIENE-SYNDIOTACTIC POLY(METHYL METHACRYLATE) BLOCK-COPOLYMERS BLENDED WITH ISOTACTIC POLY(METHYL METHACRYLATE) .2. INFLUENCE OF MOLAR MASSES

The process of stereocomplexation in blends of isotactic poly(methyl m ethacrylate)s and polybutadiene-syndiotactic poly(methyl methacrylate) diblock copolymers was studied by differential scanning calorimetry a s a function of molar mass of the constituents, annealing time and tem perature. The amount of complex formed is dependent on these three par ameters, while the temperature of decomposition of the complex is only dependent on the annealing temperature. Complex formation can be obse rved in blends containing a copolymer with a very low molar mass syndi otactic poly(methyl methacrylate) block (Mn=700). In contrast to homop olymer blends, for which two endotherms of decomposition were generall y reported, only one endotherm is observed for copolymer-homopolymer b lends. This behavior is attributed to the elastomer block.