MECHANICAL CHARACTERIZATION OF EXTENDED-CHAIN POLYETHYLENE (ECPE) FIBER-REINFORCED COMPOSITES

Composite materials reinforced with extended-chain polyethylene (ECPE) fibers are unlike typical stiff and brittle composite materials such as graphite/epoxy or fiberglass. The high ductility and energy absorpt ion capacity of the ECPE reinforcing fibers gives these composites a u nique mechanical response which makes them ideally suited for a variet y of applications. However, this dissimilarity with more common materi als requires special consideration of mechanical properties testing. I n this paper, the mechanical behavior of ECPE-fiber-reinforced composi tes is investigated using standard composite test methods. Results of these tests are presented and discussed based on the properties of the ECPE reinforcing fibers and on the assumptions inherent in the test m ethods. ECPE/epoxy composites are characterized by high ultimate tensi le strength, high tensile modulus, low shear modulus and strength, and viscoelastic response to loading. The highest available combination o f fiber strength and strain-to-failure gives this material ductility a nd energy absorption capacity significantly higher than other common c omposite materials. Applications of ECPE composites are discussed.