STUDY OF THE TRANSESTERIFICATION OF A MAIN-CHAIN MESOMORPHIC POLYESTER BY SMALL-ANGLE NEUTRON-SCATTERING

The phenomenon of transesterification of a mesomorphic polyester is investigated in the isotropic and the nematic phase using small-angle neutron scattering (SANS). In the isotropic phase, the kinetic experiment results are in good agreement with the theoretical predictions of Benoit et al. for the determination of rate constant and activation energy of the transesterification process. In the nematic phase, SANS in the intermediate scattering vector range is not sensitive to the transesterification. This is perhaps due to the cylindrical shape adopted by the polymer chain. The results are discussed as a function of the molecular weight for two different spacers.