Effects of fiber characteristics on tensile and impact properties of long fiber reinforced High‐Density Polyethylene

Abstract

AbstractDue to the requirements of high stiffness and impact strength of HDPE pipes, in this article, long fiber reinforced HDPE were developed and the effects of fiber length, volume fraction, types, and matrix/fiber interface on the mechanical properties were investigated. Tensile properties, notched impact strength, as well as microstructures were tested. The results showed that fibers increased the tensile strength, modulus, and impact strength, but decreased their plastic deformation. Larger fiber fraction indicates more fibers are involved in load bearing, but easy agglomeration. With ascending fiber length, tensile, and impact strength first increased and then decreased, whereas tensile modulus first increased and then maintained an almost constant value. Carbon fibers showed no advantages over glass fibers and basalt fibers in reinforcing HDPE due to the relatively poor interface bonding strength. Interface modification with KH550 improved the mechanical performance of composites, but the enhancement was limited. More effective methods should be developed for better performance.Highlights Fiber increases strength and modulus, but decreases plastic deformation. Critical fiber length for basalt LFT is 2.6 mm obtained from SEM. Larger fiber volume and length lead to agglomerations. Difference in BF, CF, and GF reinforced HDPE is determined by interface. Interface modification enhances mechanical properties of LFT but limited.