Single-point determination of intrinsic viscosity of semirigid thermotropic copolyesters in phenol/1,1,2,2-tetrachloroethane

A series of semirigid thermotropic copolyesters with different compositions were prepared from p-hydroxybenzoic acid (HBA), hydroquinone (HQ), terepht halic acid (TPA) and poly(ethylene terephthalate) (PET) by acidolysis react ion and following polycondensation. Fourteen procedures of calculation of t he intrinsic viscosities from a single viscosity measurement for polymer so lutions, including three proposed ones, have been applied for the copolyest ers in phenol/1,1,2,2-tetrachloro-ethane (60/40, v/v) at 30 degreesC. It is found that various forms of the Huggins and Kraemer equations, used singly or in a combined form, yield intrinsic viscosities in good agreement with those extrapolated values obtained in the usual manner from multipoint visc osity measurements over a wide range of concentrations.