Effect of solvent type on formation of PVC-solvent complex

The effect of solvent type on the structural features of PVC gels prepared from the solutions of dibutyl phthalate(DBP) and butyl benzoate(BB) were in vestigated. The influence of solvent type, i.e., diester solvent or monoest er solvent, on the mechanical responses was characterized by dynamic viscoe lastic measurements as a function of temperature, aging time, and PVC conce ntration. In the case of PVC/DBP aged gels, the transition phenomenon appea red close to 50 degreesC, whereas no such transitions were observed for PVC /BB aged gels. This transition is considered to be associated with polymer- solvent complex which can be accounted for electrostatic interaction betwee n C=O bond of solvent and H-C-CI part of PVC. While ED solvent molecules ca n not form polymer-solvent complex due to no capacity to act as a bridge be tween PVC molecular chains. FT-IR spectroscopy and DSC investigation on eit her PVC/DBP gels or PVC/BB gels was reported and discussed together with th e mechanical behavior. Electron micrographs of the dried gel prepared from the critical point drying technique reveal that the gel morphology consists of well developed three dimensional fibrous network structure independent of solvent type.