Effect of surface oxygen content and roughness on interfacial adhesion in carbon fiber–polycarbonate composites

Abstract

The effect of surface chemistry and rugosity on the interfacial adhesion between Bisphenol-A Polycarbonate and a carbon ber surface subjected to surface treatment to add surface oxygen groups was investigated. The surface oxygen content of PAN based intermediate modulus IM7 carbon bers was varied by an oxidative surface treatment. The oxygen content of the carbon ber surface increased from 4 to 22% by changing the degree of surface treatment from 0 to 400% of nominal commercial surface treatment levels. The oxidative surface treatment also causes an increase in surface roughness by creating pores and ssures in the surface by removing carbon from the regions between the graphite crystallites. To decouple the effects of surface roughness and the surface oxides on the interfacial adhesion, the oxidized ber surface was passivated via hydrogenation at elevated temperature. Thermal hydrogenation removes the oxides on the surface without signi cantly altering the surface topography. The results of interfacial adhesion tests indicate that an increase in the oxygen content of the ber does not increase the ber-matrix interfacial adhesion signi cantly. Comparing adhesion results between oxidized and hydrogen passivated bers shows that the effect of the surface roughness on the interfacial adhesion is also insigni cant. Overall, dispersive interactions alone appear to be the primary factor in adhesion of carbon bers to thermoplastic matrices in composites.

Effect of sizing on interfacial adhesion of commercial high strength carbon fiber‐reinforced resin composites

“…Part of the IFSS value might be influenced by the presence of nitrogen. Thus, the interfacial adhesion is not directly linked to the amount of oxygen, and same results were reported by Raghavendran and Ramanathan .…”

Effect of maleic anhydride‐grafted polypropylene on the flow orientation of short glass fiber in molten polypropylene and on tensile properties of composites

“…Moreover, χ 2 refers to the residual fiber length in the matrix and affinity such as the interfacial shear strength between the matrix and fibers. [17][18][19] On the contrary, modified resin was added in olefin polymer such as polypropylene to improve adhesion between olefin polymers and natural fibers, such as sisal fiber, bamboo fiber, and jute fiber. Generally, the fiber length decreases by melt compounding with the molten polymer depending on various conditions such as the type of fiber, content, and apparatus.…”

Influence of surface properties on the interfacial adhesion in carbon fiber/epoxy composites

“…[9,12,[14][15][16] Mild oxidation etch could also improve the mechanical interlocking between the fiber and the resin. [16][17][18][19] A few studies have been published on the influence of surface properties of oxidized carbon fibers on the interfacial adhesion in carbon fiber/epoxy composites. Shuji Yumitori et al [20,21] studied the effect of electrochemical oxidation of a coal tar pitch-based carbon fiber on adhesion in different electrolytes.…”

“…More recently, some studies have thoroughly compared the surface properties of non-surface treated and surface treated fibers and related it to interfacial adhesion with different matrices and different curing methods. [10,17,[22][23][24] Liu et al [25] studied the effect of electrochemical oxidation in a (NH 4 HCO 3 )/(NH 4 ) 2 C 2 O 4 H 2 O solution on the tensile strength of carbon fiber and the ILSS of carbon fiber reinforced composites and reported that carboxyl (-COOH) functional groups play an important role in enhancing the ILSS, as the acidic filler had better adhesion strength with epoxy resin than basic fillers in terms of Lewis's acid-base interaction. [26,27] However, there is some controversy whether the chemical bonding or mechanical interlock plays the governing role in the improvement of interfacial adhesion in carbon fiber reinforced epoxy matrix composites.…”