Three‐dimensionally braided carbon fiber–epoxy composites, a new type of materials for osteosynthesis devices. II. Influence of fiber surface treatment

Abstract

ABSTRACT:Interfacial adhesion between carbon fiber and epoxy resin plays an important role in determining performance of carbon-epoxy composites. The objective of this research is to determine the effect of fiber surface treatment (oxidization in air) on the mechanical properties (flexural strength and modulus, shear and impact strengths) of three-dimensionally (3D) braided carbon-fiber-reinforced epoxy (C 3D /EP) composites. Carbon fibers were air-treated under various conditions to improve fiber-matrix adhesion. It is found that excessive oxidation will cause formation of micropits. These micropits are preferably formed in crevices of fiber surfaces. The micropits formed on fiber surfaces produce strengthened fiber-matrix bond, but cause great loss of fiber strength and is probably harmful to the overall performance of the corresponding composites. A trade-off between the fiber-matrix bond and fiber strength loss should be considered. The effectiveness of fiber surface treatment on performance improvement of the C 3D /EP composites was compared with that of the unidirectional carbon fiberepoxy composites. In addition, the effects of fiber volume fraction (V f ) and braiding angle on relative performance improvements were determined. Results reveal obvious effects of V f and braiding angle. A mechanism was proposed to explain the experimental phenomena.

Comparison of short carbon fibre surface treatments on epoxy composites

“…Under a treatment temperature of 450°C the surface does not look appreciably different when compared to untreated ones, which suggests that the treatment was mild and did not cause essential morphological changes on the fibre surface [14]. However, by using the gas physical adsorption technique, Wan et al [11] reported that after treatment under a similar condition mentioned above, the total carbon fibre surface area was doubled. Their result indicated that some changes did take place on carbon fibre surface at 450°C, although it was difficult to be recognized by SEM.…”

“…Oxidation treatment of carbon fibres in hot air is one of the commonly used approaches owing to several advantages, e.g. easy operation, low cost and lack of pollution [11]. On the other hand, cryogenic treatment of carbon fibres, which could increase the fibre strength by clearing the weak layer of amorphous carbon, seems to be an interesting and relatively novel method.…”

Flexural and Shear Properties of Silica Particle Modified Glass Fiber Reinforced Epoxy Composite

“…When these modified GFs are applied in the epoxy matrix, the 'rough' surface of the GF makes the mechanical interlocking between the GF and the epoxy matrix much more pronounced. As studied by other researchers [27,28,31,32,37,38], this mechanical interlocking at the fiber-matrix interface helps to enhance the fiberÀmatrix bond and improves the flexural and shear properties of the composites. Greater work must be done to deform or shear the samples when the fiberÀmatrix bond is improved in this manner.…”

Ultra-high-molecular-weight polyethylene fiber reinforced dental composites: Effect of fiber surface treatment on mechanical properties of the composites

“…Therefore, it can be concluded that although micro-pits formed on fiber surfaces may strengthen fiber-matrix bond, higher exposure may cause great loss of fiber strength. Therefore, a trade-off between the fiber-matrix bond and fiber strength loss should be considered [40]. Placing fibers in the resin toughens the composite through different mechanisms among them are blunting the crack front path or changing the crack direction [41].…”