Preparation and Wear Resistance of Nano-Al2O3 Doped PF/EP Polymer Matrix Composite

The work aims to improve the wear resistance and mechanical properties of epoxy resin (EP), explore the friction and wear behavior of nano alumina (Nano-Al2O3) doped phenolic resin (PF)/epoxy resin (EP) composite, and reveal its wear reduction and resistance mechanism. Nano-Al2O3 was surface treated with KH550 silane coupling agent to obtain modified Nano-Al2O3, and then PF was used to cure modified EP as the polymer matrix. In the preparation method of blending, the modified Nano-Al2O3 was doped into the polymer matrix to prepare Nano-Al2O3 doped PF/EP polymer matrix composites with different ratios. The chemical structures of silane modified Nano-Al2O3, PF/EP polymer and composite were characterized by infrared spectroscopy (FTIR). The effect of PF on the wear resistance and hardness of EP based polymer was studied by Taber wear test and hardness analysis. The tribological properties of PF/EP based polymer composites with different contents of Nano-Al2O3 were compared. Scanning electron microscopy (SEM) was used to analyze the cross-section morphology of the composite and the distribution of Nano-Al2O3 in the matrix of the composite. The wear surface of EP, PF/EP polymer and composite was analyzed, and the wear mechanism and wear reduction mechanism of the composite were investigated. FTIR assay confirmed the successful modification of Nano-Al2O3 with silane, which was involved in the curing reaction of PF and EP. The results of hardness analysis and Taber wear test indicated that the addition of silane modified Nano-Al2O3 and PF improved the hardness and wear resistance of the composite. Compared with pure EP, the composite with 30wt.% phenolic content and 3wt.% Nano-Al2O3 doping had the lowest Taber wear index and the least wear weight loss, of which the hardness was increased by 86%, the wear weight was reduced by 38.7%, and the comprehensive performance was the best. The SEM results showed that the modified Nano-Al2O3 was bound well to the PF/EP polymer matrix, and the silver streaks generated by the fracture surface and the uniformly dispersed Nano-Al2O3 improved the toughness and compactness of the composite. The wear surface of Nano-Al2O3 doped composite was flatter than that of EP and PF/EP polymers. PF and EP were linked by covalent bonds to form macromolecular chains. The cross-linking of polymer chains restricted the movement of Nano-Al2O3 and reduced the shedding of modified Nano-Al2O3 during friction. Nano-Al2O3 was embedded into the network structure formed by curing, which improved the cohesion and bearing capacity of the composite. On the other hand, the shed Nano-Al2O3 filled the micropores and defects on the corresponding surface, and the formed lubricating film and the self-lubricating properties of the polymer improved the wear resistance of the composite. The excellent tribological properties of the composite are attributed to the synergistic effect of strong microhardness and lubricating film. The comprehensive analysis shows that the Nano-Al2O3 doped PF/EP polymer matrix composites prepared in this experiment are helpful to extend the current tribology research of polymer/nano-composite materials. At the same time, the improvement of polymer matrix and the introduction of reinforcement materials are considered, which is of great significance for the design of polymer/nano-composites. © 2023 Chongqing Wujiu Periodicals Press. All rights reserved.