| Popis: |
The phase behavior of several polycarbonate homopolymers and copolymers blended with PVC and chlorinated PVCs (CPVCs) has been investigated. Tetrachlorobisphenol-A polycarbonate (TCPC) is miscible in all proportions with PVC and CPVCs containing up to70.2 wt% chlorine. CPVCs having chlorine contents greater than 70.2% (by weight) are immiscible with TCPC. Tetrabromobisphenol-A polycarbonate (TBPC) exhibits phase mixing with PVC and CPVCs; however, the high Tg of this polycarbonate (260°C) prevents adequate investigation of equilibrium phase behavior. Bisphenol-A polycarbonate (BPC), tetramethylbisphenol-A polycarbonate (TMPC), and hexafluorobisphenol-A polycarbonate (HFPC) form two-phase mixtures with the vinyl polymers. Microstructural differences in the CPVCs due to chlorination method (solution chlorination vs. slurry chlorination) have no effect on the miscibility results. Miscibility was observed in several copolycarbonate/CPVC blends and was found to be dependent on copolymer composition. Using a binary interaction, mean-field theory, segmental interaction parameters were estimated for repeat unit interactions. Based on the estimated interaction parameters, miscibility in these blends is primarily the result of intramolecular repulsive effects, rather than strong intermolecular attractive forces. |
