Lösungseigenschaften methyl- und chlorsubstituierter Bisphenol-A-Polycarbonate

Solution properties of dilute polymer solutions are studied for polycarbonates from 3,3′,5,5′-tetramethylbisphenol A, from 3,3′-dimethylbisphenol A, from 3,5-dimethylbisphenol A, and from 3,3′,5,5′-tetrachlorobisphenol A in regard to the influences of the different methyl and chloro substitutions. The Mark-Houwink relationships are established in dichloromethane at 25°C. The unperturbed dimensions, evaluated from viscosity data using the Burchard-Stockmayer-Fixman method, are compared with those for bisphenol A polycarbonate. The unperturbed end-to-end distances are increased by the methyl and chloro substituents. The flexibility factors, calculated on the basis of the unperturbed dimensions and the dimensions of the freely rotating chain, indicate a greater rigidity of the polymer chain of the methyl and chloro substituted polycarbonates.