DIELECTRIC-RELAXATION SPECTRUM OF UNDILUTED POLY(4-CHLOROSTYRENE), T GREATER-THAN TG

Dielectric relaxation characteristics of undiluted, atactic poly(4-chlorostyrene), P4CS, have been determined at temperatures 406 K≤T≤446 K from measurements made at frequencies 0.2 Hz≤f≤0.2 MHz. After effects of electrical conductivity are subtracted, it is found that the normalized complex dielectric constant K.=K′ -i K″ can be represented quantitatively by the Havriliak-Negami (H-N) equation K .=[1+(iωτ0)1-α] -β, 0≤α, β≤1, except for a small, high frequency tail that appears in measurements made near the glass transition temperature, Tg. The parameter β is nearly constant, and α depends linearly on log τ0, where τ0 is a characteristic relaxation time. The parameters α and β extrapolate through values obtained from published data from P4CS solutions, and extrapolation to α=0 yields a value of τ0 which compares favorably with a published value for crankshaft motions of an equivalent isolated chain segment. These observations suggest that β may characterize effects of chain connectivity and α may describe effects of interactions of the surroundings with the chain. Experimental results are compared with alternative empirical and model-based representations of dielectric relaxation in polymers. © 1980 American Institute of Physics.