Prevention of phataltes migration from flexible PVC products

Di-(2-ethylhexyl) phthalate (DEHP) is an ester of phthalic acid, which is mainly used as plasticizer in polyvinyl chloride (PVC) to increase its flexibility, elongation and processability. The main drawback, related to its low molecular weight, is the leaching out from flexible PVC (pPVC), which affects the polymer properties limiting its employ. Moreover, the use of phthalate-based plasticizers is being questioned worldwide because of their potential toxicity to humans and environment. Migration of such harmful substances from PVC can be avoided by substituting the unsafe plasticizer or by preventing its mass transfer from polymer matrix. In this communication, promising alternatives to reduce phthalate mass transfer are discussed in detail: the chemical cross-linking of flexible PVC and the use of chlorinated polyethylene (CPE) as physical barrier against DEHP leaching. Cross-linked flexible PVC samples were obtained using a difunctional amine, namely isophoron diamine (IPDA), as cross-linking agent while two different CPE resins were employed for the preparation of new CPE/pPVC compounds. The effect of cross-linking and the efficiency of CPE in preventing plasticizer leaching were evaluated through migration tests and supported by tribological analysis. Thermal, mechanical and dynamic-mechanical properties were also studied.