Leaching of Plasticized PVC: Effect of Irradiation

Highly irradiated (2-26 MGy) polyvinyl chloride (PVC) was leached in an alkaline solution to investigate the impact of high doses on the leaching process and on the nature of the leaching products. The results show that leaching is controlled by diffusion phenomena as described by Fick's second law. The apparent diffusion coefficient (D-a) of plasticized PVC leaching products can be calculated for each sample. Irradiation at high dose causes D-a to diminish; this can be attributed to cross-linking and grafting reactions occurring during irradiation. The material microstructure thus becomes less permeable during radiolysis, which slows down the migration of species. Organic products of leaching are plasticizers contained in plasticized PVC or their degradation products. The main organic leaching products are phthalic ions formed by the hydrolysis of phthalic esters in alkaline leaching solution. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 112: 1372-1377, 2009