Polyurethanes, Miscellaneous Organic Polymers, and Silicones

The toxicity of the polymers discussed in this chapter may be generally attributed to the residual monomers, catalysts, and other additives present rather than the polymer per se. The cured polymer itself may be of high molecular weight and, consequently, more or less toxicologically inert. Carefully manufactured, highly refined polymers contain few residual toxic chemicals. However, some of the polymers discussed in this chapter, at least in some applications, go through an intermediate stage consisting of “prepolymers” (sometimes referred to as “resins”) that react further to achieve their final, cured form. An example is a polyurethane system for making foam cushions. To manufacture polyurethane foam for cushions, workers combine diisocyanate molecules with a polyol prepolymer. Such “systems” inherently have more potential for exposure of workers if not the general public to toxic monomers or other reactive chemicals. The exposure potential of glues, paints, and coatings may extend more broadly to the consumer. Thus, examination of the toxicity of the polymers discussed in this chapter focuses on monomers and prepolymers. This is not always so. Some of polymers in this chapter are used in biomedical devices or in a way that puts them in intimate contact with humans. Here, the issue of biodegradation becomes important because of potential toxicity from breakdown products of the polymer, or rejection may ensue if the polymer is incompatible with the surrounding tissues. Keywords: Polyurethanes; Foams; Elastomers; Coating adhesives; Fibers; Combustion toxicity; Amino plastics; Phenol-formaldehyde resins; Urea-formaldehyde; Melamine-formaldehyde; Furan polymers; Polybenzimidazole; Silicone elastomers