Rubber Modified Matrices

Abstract

Fiber-reinforced organic composites are increasingly being considered for structural applications in aerospace and advanced marine systems. This emphasis is basically due to the very high specific modulus and tensile strength the composite materials have to off er. The thrust behind this trend is the potential for replacing as much metallic components as possible with composite parts such that weight reduction may be achieved resulting in energy saving. In current organic composite systems, thermosetting resins such as epoxy and polyimide are widely used as matrix materials. These resins offer the combined properties of high modulus and creep resistance because of their highly cross-linked structures. However, high cross-linking generally leads to brittle materials that are subject to failure by the growth of internal flaws and progressive crack propagation. The flaws that may be anticipated include internal cracks, surface cuts and microvoids inherently present as a result of the current processing methods employed in fabricating composite parts. The growth of these flaws and the subsequent crack propagation usually cause catastrophic breakdown in structures.