MIL-HDBK-754

Abstract

<strong>GENERAL</strong> <br>The properties of all basic plastics can be enhanced by the addition of fibers, whiskers and particulate. Plastics so modified are referred to as organic or plastic matrix composites. Composites may consist of a variety of reinforcements in a number of matrix materials. For example, wood is a naturally occurring composite consisting of cellulose fibers in a lignin matrix. Man-made composites include straw-reinforced mud bricks and, more recently, concrete and asphalt. As the plastics industry and polymer chemistry developed, plastics were filled with various particulate or fillers to extend and strengthen these materials. Subsequently, fibers and weaves were used with the glass-reinforced plastics being developed in the 1940s. Today reinforcement include materials such as graphite fibers, boron, glass, organic polymer fibers, silicon carbide, and a number of new inorganic fibers. Matrix materials now being reinforced include metals such as aluminum, titanium, and copper, as well as ceramic materials. There is even a process to make carbon-fiber-reinforced carbon matrix (carbon/carbon) composites for high-temperature applications. <br>For structural composites plastics are still the principal matrix materials and include both thermoplastics and thermoses including new types such as the liquid crystal polymers. Plastics will remain the most likely matrix candidates for composites because of the substantial weight savings they offer and of the wide range of properties and the ability to tailor them. <br>The plastic matrix composites discussed in this handbook are restricted to those employing continuous fiber reinforcements.