PULTRUDED COMPOSITES IN IMPACT AND TOUGHNESS DRIVEN APPLICATIONS ACHIEVE NEW PERFORMANCE LEVELS WITH POLYURETHANE RESIN

摘要

Historically pultruded products have been manufactured using relatively brittle matrices such as polyester, epoxy and phenolic. For many years vinyl ester resins have been used as well for improved toughness but often with a reduction in processability and higher cost. Several polyurethane pultrusion technologies have now become available that provide exceptional performance potential in applications requiring damage tolerance, impact resistance and overall composite toughness. Two-component thermoset polyurethane pultrusion capability has quickly advanced from small simple shapes having only unidirectional fibers to complex profiles with perimeter width exceeding 76cm (30 inches) and utilizing engineered fiber architectures. Recently polyurethane hybrid resins have also been introduced that significantly increase the toughness and strength of pultruded composites while providing conventional processing advanatages. These resins are based on the same styrene cross-linking addition reaction as the polyester/vinyl ester technology and fall somewhat short of the properties realized by two component thermoset polyurethanes based on the step reaction of isocyanate and polyols. Thermoplastic polyurethane is yet another emerging option to provide tougher pultruded products while providing additional features not achievable with thermosets. This paper compares polyurethane resin options to traditional pultrusion resins to differentiate their niche in pultruded composite solutions for infrastructure, transportation, sporting goods, industrial, security and military applications.