Fatigue‐crack‐propagation behavior and mechanism of long hemp‐fiber‐enhanced styrene–butadiene rubber/carbon black compounds

Abstract

AbstractBiomass renewable fiber has the advantages of low cost and environmental friendliness; however, its application as a reinforcement material is limited owing to its poor reinforcement effect. Thus, expanding its application is still a major challenge. This study investigates the effect of hemp fiber (HF) of different lengths on the mechanical properties and fatigue behavior of styrene‐butadiene rubber/carbon black (SBR/CB) compounds using high‐pressure low‐shear extrusion. The results showed that the length of the HF retained by the extrusion process was approximately 10 times that of the traditional internal mixing process (internal mixing and open mixing). Interface bonding between the long HF coated with butadiene‐vinyl pyridine latex (VPL) and the SBR/CB matrix was improved significantly. This inhibited the fatigue‐crack propagation and considerably improved the dynamic fatigue life of the notched specimens. The dynamic fatigue life of the notched specimens of the composite prepared by the extrusion process was approximately nine times longer than that of the traditional internal mixing process. The results showed that the long HF length retained after the extrusion process effectively enhanced the strength of the rubber composites and significantly improved the dynamic fatigue life of rubber products under alternating stress.Highlights The raw material, hemp fiber, is a renewable resource, low cost and environmentally friendly. Pioneering a new process for preparing rubber composite materials, replacing the traditional process for preparing composite materials. High‐pressure, low‐shear extrusion process retains the length of the hemp fibers and improves rubber composites properties. Compared to traditional processes，long fiber length is 10 times longer by the extrusion process and fatigue life is increased to 9 times. High‐pressure, low‐shear extrusion process enables mass production, opening up new ideas for rubber industrial production.