COMBINED EFFECTS OF HEAT-TREATMENT AND PLASTICIZERS ON POLYVINYL-ALCOHOL FILMS

The effects of heat treatment on PVA films containing water soluble pl asticizers were investigated. Propylene glycol, glycerol and polyethyl ene glycol were used as plasticizers. There was synergism between heat treatment and the presence of plasticizers in enhancing the water res istance of PVA films. In the absence of heat treatment, however, the p lasticizers increased the aqueous solubility of PVA films. The plastic ized films further showed a lower permeability to propranolol HCl comp ared to the unplasticized films following heat treatment.