ABSTRACT
This chapter focuses on polymer-toughening methodology for three of the more demanding polyurethane polymer applications, namely, reaction injection molding (RIM), flexible foams, and dynamic elastomers. In the truest sense, the development of new polymers to meet the ever-changing needs of automotive exterior applications is done by the edisonian process. Two standard reinforcing fillers have historically been used in automotive reinforced RIM applications to provide increased stiffness and improved coefficient of linear thermal expansion and dimensional stability performance. Many different types of polyurethane-based elastomeric materials are available. Typical formulations are based on only three components (i.e., a diisocyanate, a polyol, and a chain extender), yet the number of combinations is unlimited. Polyurethane elastomers are well known for their exceptional abrasion and tear resistance, high load-bearing capability, and design flexibility. However, demands of the new in-service applications are rapidly increasing. Applications such as automotive belts, tires, and wheels require that polymer withstand high-temperature, high-stress conditions for extended periods of time.
