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A multiscale functional filler of micro–nano synergetic structure was successfully prepared via in‐situ growth of silica (SiO2) on biomimetic dopamine modified carbon fiber (CF) surface. The CF‐SiO2 hybrid as a reinforcement possessed lubricating and reinforcing effect to enhance tribological performance, thermal stability and thermomechanical property of epoxy (EP) composites. The micro–nano synergetic structure was of great importance for ameliorating the compatibility and interfacial adhesion between CF and EP matrix, which was conductive to transferring stress from matrix to fiber and alleviating stress concentration. It was concluded that the friction coefficient and wear rate of EP/CF‐SiO2 were 0.382 and 1.12 × 10−5 mm3/N·m, that is, a decline of 58% and 2.5 times, respectively, compared to EP/CF. The CF‐SiO2 hybrid exhibited excellent friction‐reducing and anti‐wear performance. [ABSTRACT FROM AUTHOR]

Carbon fabric reinforced phenolic (CFRP) composites filled with nano-Al2O3were prepared by a dip-coating and heat molding process and the tribological properties of the resulting composites under different sliding conditions were investigated systematically on a block-on-ring test rig. The worn surfaces were observed in a scanning electron microscope (SEM) to understand the mechanism. Nano-Al2O3particles, as the filler, were effective in reducing the friction coefficient and wear rate of the CFRP composites. The steady state friction coefficient of the CFRP composites filled with 4 wt.% nano-Al2O3particles was about 65.5% of that of unfilled CFRP composites, and the wear rate, in this case, was about 74.7% of that of unfilled CFRP composites. Tribological tests under different sliding conditions revealed that the filled CFRP composites seemed to be more suitable than unfilled CFRP composites for tribological applications under higher sliding speed and load. Moreover, the wear resistances of the unfilled and filled CFRP composites were found to be related to the stability of the transfer film on the counterface. [ABSTRACT FROM PUBLISHER]

ABSTRACT The polyimide (PI) composites reinforced with carbon fibers, glass fibers, and aramid fibers were fabricated by means of a hot-press molding technique and irradiated by electron or proton for a certain time. The friction and wear behavior after irradiation, sliding against GCr15 steel balls, were evaluated in a ground-based simulation facility using ball-on-disk tribosystem. The change of the chemical composition of the radiated surface was examined by X-ray photoelectron spectroscopy. The worn morphologies and radiated surfaces of the materials were observed by scanning electron microscope to reveal the wear mechanism. Experimental analysis indicated that the chemical composition of the materials changed and an irradiated layer was formed at the surface. This irradiation layer had an important effect on the friction and wear behavior of the PI composites. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40774. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, the effect of short carbon fiber (SCF), graphite (Gr) and nano-Si3N4 on the friction and wear behavior of polyimide (PI) composites were studied using a block-on-ring arrangement. Experimental results revealed that single incorporation of SCF and Gr can improve the friction-reducing and anti-wear abilities of the PI composites significantly. However, nano-Si3N4 deteriorated the wear resistance of the PI composite drastically as single filler. A synergistic effect was found for the combination of nano-Si3N4 and SCF and Gr, which lead to the best tribological properties. It also can be found that the filled PI composites exhibited better tribological properties under higher PV product (the product of load and sliding speed). Moreover, the filled PI composites showed better tribological properties under oil lubrication and worse tribological properties under water lubrication compared with that under dry sliding condition. [Copyright &y& Elsevier]

Abstract: Carbon fibers (CFs) were treated by HNO3 plus diamine modification and incorporated into polyimide (PI) matrix to prepare polymer composites. The friction and wear properties of the PI composites reinforced by untreated and treated carbon fibers (15wt.%), sliding against GCr15 steel, were studied on an M-2000 model ring-on-block test rig under dry sliding. Experimental results showed that the surface treatment largely reduced the friction and wear of CFs reinforced PI (CFs/PI) composites. The worn surface of CFs/PI composites and the transfer films formed on the surface of the counterpart ring sliding against CFs/PI composites were investigated by SEM. Compared with the untreated ones, the surface modified CFs can enhance the tribological properties of CFs/PI composite efficiently due to the improved adhesion between CFs and PI matrix. The differences in the friction and wear properties of CFs/PI composites are closely related with the sliding condition such as sliding rate and the applied load. Research results show that CFs/PI composites exhibited better tribological properties under higher load and sliding speed. [Copyright &y& Elsevier]

Polyacrylonitrile (PAN)-based carbon fabric (CF) was modified with strong HNO3 oxidation and then introduced into polyimide (PI) composites. The friction and wear properties of the carbon fabric reinforced polyimide composites (CFRP), sliding against GCr15 stainless steel rings, were investigated on an M-2000 model ring-on-block test rig under dry sliding. Experimental results revealed that the carbon fiber surface treatment largely reduced the friction and wear of the CFRP. Compared with the untreated ones, the surface-modified CF can enhance the tribological properties of CFRP efficiently due to the improved adhesion between the CF and the PI matrix. Scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS) study of the carbon fiber surface showed that the fiber surface became rougher and the oxygen concentration increased greatly after surface treatment, which improved the adhesion between the fiber and the PI matrix and improved the friction-reduction and anti-wear properties of the CFRP. [ABSTRACT FROM AUTHOR]

Abstract: To improve the friction and wear behavior of carbon fabric reinforced polymer composites (CFRP), nano-SiO2 was deposited on the fabric surface. The friction and wear behavior of the resulting composites were investigated on a model ring-on-block test rig. Experimental results revealed that fiber surface treatment contributed to largely improve the tribological properties of the CFRP composites. Scanning electron microscope (SEM) investigation showed that the worn surface of the surface modified CFRP composite was smoother under given load and sliding rate. Field emission scanning electron microscopy (FESEM), FTIR and X-ray photoelectron spectroscopy (XPS) studies of the carbon fiber surface showed that nanostructured Sio2 thin film can be obtained by SiO2 sols deposition, which improved the adhesion between the fiber and phenolic matrix and hence to improve the friction-reduction and anti-wear properties of the CFRP composite. [Copyright &y& Elsevier]

Abstract: Carbon fabric (CF) was surface treated with silane-coupling agent modification, HNO3 oxidation, combined surface treatment, respectively. The friction and wear properties of the carbon fabric reinforced phenolic composites (CFP), sliding against GCr15 steel rings, were investigated on an M-2000 model ring-on-block test rig. Experimental results revealed that combined surface treatment largely reduced the friction and wear of the CFP composites. Scanning electron microscope (SEM) investigation of the worn surfaces of the CFP composites showed that combined surface modified CFP composite had the strongest interfacial adhesion and the smoothest worn surface under given load and sliding rate. SEM and X-ray photoelectron spectroscopy (XPS) study of carbon fiber surface showed that the fiber surface became rougher and the oxygen concentration increased greatly after combined surface treatment, which improved the adhesion between the fiber and the phenolic resin matrix and hence to improve the friction–reduction and anti-wear properties of the CFP composite. [Copyright &y& Elsevier]

The poor interfacial compatibility between functional fillers and matrix greatly restricts development of polymer composites. Therefore, in the present paper, carbon fibers (CFs) were modified by biomimetic polydopamine (PDA) and amino silane (KH550) to improve interfacial bonding strength with epoxy (EP) substrate. The grafting of PDA and KH550 was divided into "PDA", "PDA-KH550" and "(PDA + KH550)" methods for regulating interfacial compatibility and exploring the reaction mechanism. Improved interfacial strength was beneficial to transfer stress from the matrix to fillers. Consequently, mechanical properties of modified CF/EP were obviously superior to those of unmodified EP/CF. Besides, wear resistance of EP/CF-(PDA + KH550) had an increase of 76%, 67%, 60% and 49% compared to that of EP, CF/EP, CF-PDA/EP and EP/CF-PDA-KH550. Image 1 • PDA and KH550 were used to regulate interfacial compatibility of CF and EP. • The different reaction mechanisms of PDA and KH550 were explored. • The tribological mechanism of modified CF/EP were systematically analyzed. • "CF-(PDA + KH550)" method significantly improved simultaneously the mechanical properties and wear resistance. [ABSTRACT FROM AUTHOR]