Tribological properties of polyimide fabric-epoxy composites modified by hollow silica microspheres

The polyimide (PI) fabric/epoxy (EP) composites modified with different content of micro-SiO2 hollow spheres were prepared by dip-coating and subsequently hot-press process. For comparison, the pure EP and the unmodified PI fabric/EP composite were also fabricated. The differential scanning calorimetry was conducted to investigate the crosslinking reaction of composites. The results indicated that there exhibited a remarkable improvement in the mechanical and tribological properties of PI fabric/EP composites after incorporating the micro-SiO2. The best tribological properties were obtained when the content of micro-SiO2 was 2 wt%, whose wear rate was 71.9% lower than that of unmodified PI fabric/EP composite. The worn surfaces were observed by a scanning electron microscope to illustrate the friction mechanisms. Note that the skeleton network structure of fabric throughout the whole composites supported the matrix. At the same time, the microparticulates filled in the interstices of fabrics interwoven structure and the gaps between layers of fabrics, which propped up the skeleton network of fabric under the high frictional load and afford excellent interface between fabrics and EP. This ensures the outstanding tribological properties of PI fabric/EP composites. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers