Electrodeposition of a polymer interphase in carbon‐fiber composites

Abstract

The performance of an electrodeposited interphase of poly(butadiene‐co‐maleic anhydride) (BMA) in carbon‐fiber composites is investigated. Carbon fibers are electrocoated with BMA from an aqueous solution and the coated fibers are fabricated into composite bars for evaluation of mechanical properties. These composites show superior impact strength, but lower interlaminar shear strength, compared to composites made from commercially treated fibers. It is suggested that unsaturation in the butadiene segments of the interphase polymer leads to the formation of a crosslinked layer during electrodeposition and subsequent drying. Inadequate penetration of this interphase by bulky epoxy molecules leads to a weak interphase/matrix interface which is the locus of failure, generating the observed mechanical properties. These conclusions are supported by examination of the fracture surfaces by Scanning Electron Microscopy. Further evidence of lack of matrix penetration into the interphase comes from electron microprobe line scans for bromine performed on cross‐sections of single‐filament composites, the bromine being introduced into the matrix via a brominated epoxy resin. Appropriate control of the chemical structure and physical characteristics of the interphase polymer is thus indicated, for acieving simultaneous improvements in impact and interlaminar shear strengths.

Interfacial toughening and consequent improvement in fracture toughness of carbon fiber reinforced epoxy resin composites: induced by diblock copolymers

“…The other most effective method is by coating the carbon fibers with a ductile polymeric material before they are incorporated into a matrix. A variety of polymer coatings such as anhydride copolymers [10], acrylonitrile copolymers [11], polyvinyl alcohol [12] and epoxy coating [13] have been supplied to carbon fibers, and consequently improving the fracture toughness of reinforced composites by modifying the mode of failure and thus the potential energy absorbing capacity. However, these coatings usually provide weak bonding at the interface; thick coatings also result in the reduction of the composite strength and modulus.…”

Improvement in impact property of continuous glass mat reinforced polypropylene composites

“…When the interfacial adhesion is good, debonding becomes more difficult and the advancing crack propagates through the fibers, resulting in low impact properties. 8,9 So it is necessary for obtaining GMT-PP with excellent comprehensive mechanical properties to design a proper interfacial adhesion. After maleated polypropylene (PP-g-MAH) was added to the PP matrix, the chemical and polar interactions of PP matrix-maleated PP-fiber improve the interfacial adhesion between the fiber and the matrix.…”

“…[1][2][3][4][5][6][7] Generally, an improvement of the interfacial adhesion will result in an increase in the shear strength at an expense of the impact strength. 8,9 To eliminate this conflict, polymer interlayers that can absorb impact energy and can form physical and/or chemical bonds with the matrix were coated onto the fibers. 10 -13 The mechanisms of rubber toughening in combination with fiber reinforcement in PP matrix were investigated by Jang et al They believed that the delamination was the dominant failure mode in PP matrix composites subjected to low-velocity impact.…”

Comparison of Interfacial Properties of Electrodeposited Single Carbon Fiber/Epoxy Composites Using Tensile and Compressive Fragmentation Tests and Acoustic Emission

“…Among them is the electrodeposition (ED) (16)(17)(18), which is a process by which a film is deposited on a conductive carbon fiber from a dispersion of colloidal ions in aqueous solution with a charge opposite that of the carbon fiber surface. By optimizing the treatment process, a polymeric coating can be deposited with the desired composition and thickness homogeneously to improve the interfacial properties.…”