Tensile behavior of unidirectional polyethylene fibers PMMA and glass fibers - PMMA composite laminates

Unidirectional (UD) composite laminates based on glass fibers (GF) and high -performance polythylene fibers (PEF) were prepared with partially polymeri zed methyl methacrylate (MMA) at room temperature, followed by heating at 5 5 degrees C (well below the softening point of PEF) for 2 h. The tensile st rength, modulus of elasticity, fiber efficiency and strength efficiency of both the composite laminates, loaded parallel to the fibers, at the same vo lume fraction range, were investigated. All the properties were compared be tween the two composite laminates. It was observed that the measured tensil e strength and modulus of elasticity deviated from the values calculated fr om the Rule of Mixture (ROM). The deviation was minimal at the lower volume fraction of fibers, and increased with the fiber volume. An interesting fe ature that was observed was that the efficiencies of PEF-reinforced composi te was higher than that of the GF-reinforced composite at the same volume f raction of the fibers. (C) 2000 John Wiley & Sons, Inc.