Polymer-matrix composites: New fibers offer new possibilities

Abstract

If one class of material could represent the transition to the new millennium, it would be the polymer-matrix composite (PMC). From missile components to golf clubs, an ever increasing number of products or specifi c devices are made of PMCs. Some are new developments, such as the carbon fi ber composites in modern commercial aircraft. Others are benefi cial to both our health and the environment. Typical examples are the aramid fi ber composites replacing asbestos in automotive brakes and clutch linings, as well as recyclable coconut fi ber composites substituting synthetic fi bers in automobile seat cushions. Polymer-matrix composites are normally composed of a matrix reinforced with a synthetic or natural fi ber. The matrix acts as the intermediate by which an externally applied load is distributed to the stronger and stiffer fi bers that structurally support the composite. It protects the fi bers from outside chemical (or even atmospheric) attack and abrasion. The plasticity of the matrix serves as a barrier to crack nucleation/propagation, and as such prevents catastrophic rupture. The real advantages in terms of fl exibility and expanding potential for the PMC are the different fi bers available. Glass fi ber is the most popular owing to its low price, easy processing, high specifi c strength, and chemical inertness. Carbon fi ber is the current preference for advanced structural composites. It is the stiffest and strongest of all fi bers. Carbon fi ber manufacturing and its composite processing are curPolymer-Matrix Composites: New Fibers Offer New Possibilities