Effect of solvent type on formation of PVC-solvent complex

Abstract

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 investigated. The influence of solvent type, i.e., diester solvent or monoester solvent, on the mechanical responses was characterized by dynamic viscoelastic measurements as a function of temperature, aging time, and PVC concentration. In the case of PVC/DBP aged gels, the transition phenomenon appeared 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 between C=O bond of solvent and H-C-CI part of PVC. While ED solvent molecules can not form polymer-solvent complex due to no capacity to act as a bridge between PVC molecular chains. FT-IR spectroscopy and DSC investigation on either PVC/DBP gels or PVC/BB gels was reported and discussed together with the 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.