INTERACTION PARAMETERS FOR BLENDS CONTAINING POLYCARBONATES .3. POLYCARBONATE COPOLYMERS STYRENE-BASED COPOLYMERS

The phase behaviour of binary blends of copolycarbonates of tetramethyl bisphenol-A and bisphenol-A (TMPC-PC) with copolymers of styrene with acrylonitrile (SAN) or styrene with methyl methacrylate (SMMA) has been examined as a function of composition of each copolymer. The interaction parameters for TMPC-PC blends with each SAN copolymer and each SMMA copolymer were evaluated from the lower critical solution temperature type phase boundary using the lattice fluid theory of Sanchez and Lacombe. From such information for several copolymer compositions, bare interaction parameters for mixing of various monomer unit pairs (DELTAP(ij)*) were calculated using a binary interaction model. Additionally, from miscibility maps, Flory-Huggins type energy densities (B(ij)) have been computed for various monomer unit pairs. The interactions of acrylonitrile with other monomer units (styrene, PC and TMPC) are strongly repulsive in each case while the interactions of MMA with these monomer units are weakly repulsive.