Heating up the Market for Polyurethane Polymers

The polymer morphology of polyurethanes gives them versatility and utility in many applications. The formation of hard domains and soft domains along with the selection of the functional type of domains, whether urethane or urea, give these polymers desirable mechanical properties typically in the range of -30°C to 150°C. Polyurethane polymers capable of withstanding temperatures approaching 200°C can advance the use of these polymers into new or extended fields of applications. Examples of these applications include automotive exterior panels that are exposed to high heat cure ovens during car assembly, under the hood parts, muffler shields and the like. Other applications for heat resistant polyurethane elastomers, coatings and foams can be quite numersous and left to the reader to envision. An understanding of the critical factors affecting the capability of polyurethane materials to withstand heat is necessary in order to design a polymer structure that is tailored to fit a particular high heat application. A fundamental study was performed using a combination of practical polyurethane/urea polymers produced via reaction injection molding process and laboratory model urethane and urea compounds. After the critical parameters were identified, two types of polymer modifications were evaluated for improved resistance to polymer degradation due to heat exposure, and will be presented here. One study examined chemical modification of the polymer backbone while the second determined the effect of changing the physical attributes of the polymer to resist water absorption. Both modifications improved polymer thermal stability as measured by a practical testing methodology such as physical property retention after high heat exposure.