EFFECTS OF POLYCARBONATE MOLECULAR-STRUCTURE ON THE MISCIBILITY WITH OTHER POLYMERS

An exploratory investigation of the equilibrium phase behavior of binary blends of various polycarbonates with polystyrene (PS), poly(methyl methacrylate) (PMMA), bisphenol A polycarbonate (BPA-PC), and tetramethylbisphenol A polycarbonate (TMPC) is described. The variations in polycarbonate structure primarily involved substitutions onto the phenyl rings in two or four of the available positions and changing the connector group between the two phenyl rings, or both, of the bisphenol monomer. Polar connector groups promote favorable interactions with PMMA while ring substitution with methyl groups improves miscibility with PS. Other structural changes in the connector group or on the phenyl rings can act against the miscibility of polycarbonates with PMMA or PS. A wide range of polycarbonates was found to be miscible with BPA-PC and TMPC. The effect of PMMA and PS molecular weight on the miscibility of blends with selected polycarbonates was used to obtain more detailed information about their interactions. The use of this information to design useful polymer blends is discussed.