Dynamic mechanical and gas transport properties of blends and random copolymers of bisphenol‐A polycarbonate and tetramethyl bisphenol‐A polycarbonate

Abstract

Dynamic mechanical and gas transport properties for homogeneous homopolymer blends and random copolymers of bisphenol‐A and tetramethyl bisphenol‐A polycarbonates (PC‐TMPC) were determined. The gas transport measurements were performed at 35°C for the gases He, H2, O2, Ar, N2, CH4, and CO2. The results show that the copolymers have lower permeability, apparent diffusion, and solubility coefficients than the blends. Permeability coefficients for blends follow a semilogarithmic ideal mixing rule while copolymers exhibit negative deviations from this. Specific volume measurements show that the free volume available for gas transport is slightly larger in copolymers than in blends of the same composition. These apparently contradictory results may relate to the differences in local mode chain motions observed for the copolymer and blend series. The γ relaxation processes in PC and TMPC seem to operate independently in the blends (no intermolecular coupling) while there is clear evidence for intramolecular coupling in the copolymers. © 1992 John Wiley & Sons, Inc.

PEG-based hydrogel membrane coatings

“…(8). However, deviations from ideal mixing behavior can indicate the occurrence of additional intermolecular interactions [32]. Such deviations are observed with AA copolymers; the experimental specific volumes are somewhat lower than the predicted specific volumes.…”

“…3b. The specific volumes of the pure polymerized monomers were measured and used, along with an ideal mixing model, to predict copolymer specific volume [32]…”

“…Solid lines represent specific volume predicted by the ideal volume additivity model[32]. Effect of copolymer composition on glass transition temperature of AA, HEA, and PEGA copolymers.…”

Control of phase separation behavior of PC/PMMA blends and their application to the gas separation membranes

“…[1][2][3][4][5][6][7][8][9][10] Membranes for gas separation prepared by blending are of great interest because one may be able to achieve a useful combination of the advantages of each material into a single product and expect a continuous range of properties by controlling blend composition. Transport rates of several gases through the membranes are sensitive to micro-and macrostructure of the polymer blend, chain packing, segment interaction, and local chain dynamics.…”

Solid-state structure and properties of poly(ethyl methacrylate)/phenoxy blends

“…No positive deviation was seen in the 80/20 blend, so a change in the specific volume is not the main reason that accounts for the observed modulus behavior. This lack of change in the specific volume values of the blends, 40,44 indicates either that the migration of the two low molecular weight components had not influence on the specific volume, or that it was counteracted by the presence of small amounts of the other blend component. The accuracy of the experimental values of Ϯ0.003 cm 3 g Ϫ1 means that these data are significant, because specific volume changes of 0.007 cm 3 g Ϫ1 have been observed in Ph with plasticizer amounts as low as 2.5%.…”