K<scp>UHN</scp>‐M<scp>ARK</scp>‐H<scp>OUWINK</scp>‐S<scp>AKURADA</scp> relations and unperturbed dimensions of poly(di‐<i>n</i>‐alkyl itaconates)

Abstract

Abstract K UHN ‐M ARK ‐H OUWINK ‐S AKURADA relations for poly(dimethyl‐, diethyl‐, di‐ n ‐propyl‐, di‐ n ‐butyl‐, di‐ n ‐hexyl‐, di‐ n ‐octyl‐, di‐ n ‐decyl‐, and di‐ n ‐undecyl itaconate) were established in toluene at 25°C. The decreasing exponent a from 0.80 to 0.61, in going from lower to higher members of the series, reflects the decreasing solvent power of toluene. Observed high molecular weights of the polymers are in disagreement with formerly assumed strong chain transfer to monomer in the propagation step. σ‐parameters, evaluated according to the K URATA ‐S TOCKMAYER extrapolation procedure, within limits of 1.98 and 3.50, indicate strong and progressively increasing steric hindrance to free rotation in this polymer homologueous series.