Internal plasticization of PVC
Patrick W. Skelly, Longbo Li, Rebecca Braslau
Abstract
Polyvinyl Chloride (PVC) is among the most abundant plastics worldwide. Phthalates and other plasticizers—small molecules added to PVC to impart flexibility—have raised numerous health concerns due to their tendency to migrate out of PVC, where they can be ingested or contaminate the environment. Internal plasticization, in which a plasticizer is covalently bound to the PVC backbone, offers a solution to the problem of plasticizer migration. This comprehensive review covers the preparation of internally plasticized PVC in the literature. Strategies fall into three main categories: nucleophilic substitution of chlorine atoms on PVC; graft polymerization using plasticizing monomers, usually from defect sites in the PVC backbone; and copolymerization of vinyl chloride with monomers bearing plasticizing species. Minimizing cost and number of synthetic steps are important considerations when designing plasticizers for this large-scale commodity plastic.