Influence of biodegradation on the tensile and wear resistance properties of bio-derived CaCO3/epoxy composites

This research work investigated the influence of palm kernel shell-derived calcium carbonate (CaCO3) fillers and biodegradation on the tensile and wear properties of epoxy composites. CaCO3 fillers were obtained from pulverised charred palm kernel shell (CPKS) particles. The composites contained between 2 wt.% and 20 wt.% of CaCO3 fillers. The samples were characterised for microstructural examination, phase analysis, tensile, and wear properties. The results revealed that the composite samples possessed enhanced properties compared with the neat matrix due to the presence of CaCO3 fillers. No particle debonding was observed on the fracture surfaces of the composite samples, which suggested that a strong interface existed between the fillers and the matrix. This could be attributed to the elimination of amorphous content from the CPKS particles during the pyrolysis process, which yielded highly crystalline CaCO3. This was strongly supported by the XRD results. Furthermore, the effect of biodegradation on the composite properties was studied on the samples interred for 90 days in natural soil. Degradation increased as the fraction of CaCO3 fillers increased due to the microbial degradation of CaCO3 fillers and the investigated properties deteriorated as compared with samples that were not buried. It was concluded that bio-derived CaCO3 fillers could function as reinforcement particles in an epoxy matrix and enhance its degradation when added in large quantities to the matrix.