PHYSICAL GELS FROM POLY(VINYL CHLORIDE) - EFFECT OF SOLVENT TYPE

The gelation of poly(vinyl chloride) has been studied in homologous diesters and monoesters. The relation between the modulus, E, and the swelling degree, G(v), at swelling equilibrium has been found to depend upon the solvent type. Two classes of universality have been found obeying power laws: gels in monoesters, E = 24.5G(v infinity)-2.72+/-0.1 kPa; gels in diesters, E = 18.6G(v infinity)-1.54+/-0.1 kPa. Light scattering investigations on aggregates have also revealed two types of behavior depending upon whether diesters or monoesters are used. Finally, DSC experiments show that diester solvent molecules most probably participate in the formation of additional links (polymer-solvent complexes) while monoester solvent molecules act essentially as plasticizers. The experiments reported herein give further support to a model first suggested by Mutin and Guenet.