Study of Thermoreversible Aggregates from Chemically-Modified PVCs

Abstract

We report on a light scattering study performed on suspensions of aggregates of PVC and chemically-modified PVCs in diethyloxalate (DEO). The maximum in the scattering function reported by Mutin and Guenet is again observed. Its position, q m, depends upon the degree of chemical modification at constant polymer concentration: the larger the degree of modification, the lower the value of q m . The radius of gyration and the weight-averaged molecular weight of the aggregates are determined as a function of the preparation concentration from highly diluted suspensions. The radius of gyration is found to remain virtually unchanged when augmenting the degree of modification while a near 2-fold increase of the weight-averaged molecular weight is observed, the latter being consistent with the variation of q m . All these results point toward a cross-sectional growth of the fibrillar aggregates with chemical modification while the longitudinal fractal dimension does not vary significantly. Viscometry measurements provide further support to these conclusions.