Leaching of plasticized PVC: Effect of irradiation

Abstract

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 crosslinking 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.

Empirical estimation of pollution load and contamination levels of phthalate esters in agricultural soils from plastic film mulching in China

“…PAEs are important contaminants derived from mulching plastic film residues because of their common and large-scale use as plasticizers in PVC film. Moreover, freely mobile and leachable phase PAEs in PVC products enhance PAE release from the residues of plastic films (Amato et al 2001;Gómez-Hens and AguilarCaballos 2003;Colombani et al 2009). As a result, ubiquitous PAE pollution occurs in agricultural land mulched with plastic film (Ma et al 2003;Chen et al 2011).…”

“…PAEs are not irreversibly bound to the polymer matrix, but present in the PVC as a freely mobile and leachable phase, resulting in migrating from the plastic to the external environment under certain conditions (Balafas et al 1999;Gómez-Hens and Aguilar-Caballos 2003;Colombani et al 2009). The yearly production of PVC is approximately 20 million tons, and it was estimated that the PVC waste amounts were up to 5.4 million tons in 2010 and a 40 % rise of that waste is likely to occur in 2020 (Teil et al 2006).…”

Contamination from Sterilization Procedures

“…Phthalic ions, formed by hydrolysis of phthalic esters, were leached in higher extent. While a small amount of radiolysis products, mostly phthalic ions, was obtained from samples with greater amounts of additives [63], no formation of phthalic ions was observed in the other studies from PVC samples, although several other compounds were formed (see Table A.4, Appendix). 12.16), the authors considered that when plasticized PVC is irradiated, grafting reactions occurs, implying that radiolysis products are not leachable anymore.…”

“…Colombani et al [63] irradiated plasticized PVC samples (Plastisol ® ) with doses of 8 MGy and extracted the radiolysis products in alkaline solutions at 20 and 50°C. As the sample comprised only 27% pure PVC, the remainder being organic and inorganic additives, mainly di-isononyl phthalate, di-n-butyl phthalate, and 2-ethylhexyl diphenyl phosphate, the quantity of released compounds (Table 12.13) was much more related to the additives than to the PVC itself.…”

“…16 TOC measurements of unirradiated and irradiated plasticized PVC leached at 50°C. leaching of unirradiated PVC (×), leaching of PVC irradiated to 2 MGy (), leaching of PVC irradiated to 18 MGy (), leaching of PVC irradiated to 26 MGy ()[63].…”