Novel polyurethane elastomeric composites reinforced with alumina, aramid, and poly(p-phenylene-2,6-benzobisoxazole) short fibers, development and characterization of the thermal and dynamic mechanical properties

Polyurethane is an extremely versatile material having seen use in a variety of applications. However, its relatively weak mechanical properties limit the scope of applicable functions. In this paper, composite elastomers of polyurethane have been reinforced with Kevlar pulp, Alumina micro fibers, and poly(p-phenylene-2,6-benzobisoxazole) (PBO) fibers. The thermal and dynamic mechanical properties were characterized by thermogravimetric analysis (TGA), thermomechanical analysis (TMA), and dynamic mechanical analysis (DMA). Upon the addition of the reinforcing fibers an improvement in thermal stability as well as a significant reduction of 37% to the coefficient of linear thermal expansion was found. Additionally, an improvement of 97% to the storage modulus (G′) was found with the inclusion of a small amount of PBO fibers, 1wt%, to the polyurethane matrix.