The plasticizer market: an assessment of traditional plasticizers and research trends to meet new challenges

Plasticizers have long been known for their effectiveness in producing flexible plastics for applications ranging from the automotive industry to medical and consumer products. The plasticizer industry has grown with the use of plastics worldwide. Recent plasticizer research has focused on technological challenges including leaching, migration, evaporation and degradation of plasticizers, each of which eventually lead to deterioration of thermomechanical properties in plastics. Human exposure to certain plasticizers has been debated recently because di(2-ethylhexyl) phthalate, used in medical plastics, has been found at detectable levels in the blood supply and potential health risks may arise from its chronic exposure. The current paper presents a brief history and an overview of the traditional plasticizers currently available in the world market, discusses some of the problems associated with the end uses of these plasticizers and reviews recent scientific approaches to resolve these problems. The definition of an ideal plasticizer changes with each application; thus, this paper addresses technical issues first from a broad perspective, and then with a focus on leaching, migration, evaporation and degradation issues. Several approaches to reduce leaching and migration of plasticizers are discussed, including surface modification of plasticized polymers and the application of alternative plasticizers and oligomers to meet technological requirements. New approaches to reduce evaporation and degradation of plasticizers are discussed, with the aim of formulating long-lasting flexible plastics and minimizing the ultimate environmental impact of these chemicals. The development of fire-retardant plasticizers and novel plasticizers for use in biodegradable plastics are also included. (C) 2004 Elsevier Ltd. All rights reserved.