Final Report on the Safety Assessment of Polyoxymethylene Urea

The toxicity of the polymers discussed in this chapter may be attributed generally 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 oligomers or resins) that react further to achieve their final, cured form. These may have high levels of monomers or additives that could present an exposure hazard to workers.

Polyurethanes, Miscellaneous Organic Polymers, and Silicones

Cragg

2024

Miscellaneous Organic Polymers

Skoglund,

Roy

2023

Polymers are advanced materials composed of many repeating monomer units; organic polymers are polymers that essentially contain carbon atoms in the backbone. Significant volumes of organic polymers are manufactured each year. Plastic products manufactured from these polymers can be as simple as toilet seats and single‐use grocery bags, or as tough as bulletproof materials, space suits, chemical resistant gaskets, or as sophisticated as implantable medical devices. Key features of plastics are modified by the selection of the resins, the manufacturing processes, and the additives used. Plastics are divided up into three main groups: thermoplastics, thermosetting plastics, and elastomers. Exposure to monomers, polymers, resins, and plastics can occur during the initial polymerization and manufacturing of the resins, the subsequent polymerization and manufacturing of the plastics and finished products, during use of the finished product, and during the product's end‐of‐life stage. This chapter focuses on the human health hazard profile of several miscellaneous organic polymer resins used to form thermoplastics and thermosetting plastics. These polymers include phenolic resins, aminoplastic resins, furfuryl alcohol resins, polyvinylpyrrolidone resins, polybenzimidazole resins, and polylactic acid resins. Most of the plastics manufactured from these resins are resistant to biodegradation; however, a few can be biodegraded. In addition to the toxicology profiles, this chapter discusses production and use, potential exposures, hazard classification, sensitive applications such as food‐contact and medical applications, and exposure guidelines.

Polyurethanes, Miscellaneous Organic Polymers, and Silicones

Cragg¹

2001

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.