A comparative study of the mechanical and tribological properties of UHMWPE composites with synthetic and natural wollastonite

This study presents a comparative analysis of natural and synthetic wollastonite as reinforcing fillers for ultra-high molecular weight polyethylene (UHMWPE). Microstructural characterization showed that synthetic wollastonite (SW) retains a uniform nanoscale acicular morphology, whereas mechanically ground natural wollastonite (NW) exhibits a broad particle size distribution. Composites containing SW demonstrated superior tribological performance, with a 6-fold reduction in specific wear rate and a 4-fold decrease in linear wear compared to initial UHMWPE. They also exhibited a 34% increase in tensile strength and a 15% improvement in elongation at break. In contrast, NW-filled composites showed better mechanical reinforcement, increasing compressive strength by 34%, tensile strength by 37%, and elastic modulus by 66%. These findings highlight the distinct advantages of each filler type and provide guidance for material selection depending on application requirements. To achieve uniform dispersion of SW particles, ultrasonic co-dispersion of the components was applied for 10 min, resulting in a 40% increase in tensile strength and a 70% increase in elastic modulus relative to initial UHMWPE.