Urethane Polymers

Abstract

AbstractThe properties of thermoplastic and thermoset polyurethanes are discussed. The subjects include flexible and rigid polyurethane foams, poly(urethane isocyanurate) foams, thermoplastic polyurethane elastomers, thermoset cast and RIM elastomers, engineering thermoplastics, liquid crystalline polyurethanes, and polyurethane containing interpenetrating polymer networks. Principal raw materials, such as isocyanates, polyether polyols, and polyester polyols, as well as catalysts, fire retardants, and surfactants, are described. The manufacture of flexible foam, rigid foam, coatings, adhesives, sealants, and elastomers are included, as is the use of polyurethane ionomers in aqueous dispersions and blocked isocyanates in one‐component and powder coatings applications. The global trend in polyurethanes is a shift from toluene diisocyanate‐based formulations to polymeric isocyanate and 4,4′‐methylenebis(phenyl isocyanate) whenever possible, and substitution of chlorinated fluorocarbon blowing agents by hydrochlorofluorocarbons, hydrofluorocarbons, or hydrocarbons. Recycling of polyurethanes, health and safety factors, including toxicity and safe handling of isocyanates and tertiary amine catalysts, as well as principal uses of polyurethanes and market information, are all discussed.