Poly(vinyl alcohol)-collagen hydrolysate thermoplastic blends:: II.: Water penetration and biodegradability of melt extruded films

Water solubility of polyvinyl alcohol (PVA) is related to degree of hydrolysis, molecular weight and modification during blending in the presence of other processing additives. In the present paper the effect of collagen hydrolysate (CH), an abundant waste product of the leather industry, and glycerol on PVA water sensitivity has been investigated. This study is a continuation of the previous research on experimental design optimisation of PVA-collagen hydrolysate blends (P. Alexy, D. Bakos, S. Hanzelova, L. Kukolikova, J. Kupec, K. Charvatova, E. Chiellini, P. Cinelli, Polymer Testing 2003, 22 doi:10.1016/S0142-9418(03)00016-3). CH content affects water penetration into the prepared blown films, affecting therefore their solubility. An increasing content of CH in PVA based blends shortens the time to the first disruption of the film after immersing in water, restraining the negative effect of glycerol on solubility. Water penetration into film is influenced by both added components-glycerol and CH, and mutual effects depend upon their proportional amounts in the blends. Pure PVA film presented limited biodegradation at low temperature (5 degreesC). The CH addition in the blend significantly increases biodegradation rate at that temperature. PVA/CH blends properties are of practical relevance for applications as hospital laundry bags and containers of water-soluble substances, such as chemical agents for treatment of waste and potable water, fertilizers, washing agents, sanitary products, etc. (C) 2003 Elsevier Science Ltd. All rights reserved.