Influence of Ion-Beam Carbon-Fiber Surface Treatment on the Angle of Wetting by Epoxy Oligomers

Abstract

The influence of the regimes of modification of carbon fibers by an argon ion beam on the change in the angle of their wetting by an epoxydiane oligomer has been investigated. It has been shown that ion-beam treatment of carbon fibers leads to a considerable decrease in the wetting angles (the difference between the wetting angles for nonmodified and modified fibers is up to 32.2-38.7 o ). Accordingly, there is also an increase in the value of the equilibrium work of adhesion by 36.2-41.6% in the contact zone. It has been established that ion-beam treatment of carbon fibers by argon ions leads to an increase in the shear strength when microplastics based on them are formed.As was predicted as far back as the last century, carbon fibers (CF) remain the most promising filler of polymer composite material in the current century as well [1,2]. The problem of maximal realization in the compositions of the unique properties of the carbon-fiber filler determined by the interphase interaction of heterogeneous components is as acute [3]. Surface and internal defects have a negative effect on the cohesive strength of fibers with the polymer binder as well as on the strength of the fibers. The numerous experimental data show that under extension of carbon fibers a break occurs almost exclusively at the place of a visually observable defect. Therefore, the problem of increasing the adhesive strength at the interface and its stability under operating conditions remains central and the most important. Modification of the fiber surface is one of the easiest and most promising ways of controlling the interphase interaction of fibers with the polymer matrix. Various modification techniques are known, e.g., oxidation, grafting of functional groups, and their electrochemical or plasmachemical treatment [4][5][6]. The modification efficiency depends on the surface purity of fibers.The CF surface can also be polluted as a result of the technological features obtaining them. The surface defects that most strongly affect the observed strength of fibers, the quality of modification, and their adhesion to the binding material can be removed by chemical etching (in a liquid medium or by oxidation in a gaseous medium), as well as by ion-plasma or ion-beam treatment of CFs. However, the chemical cleaning methods do not always allow one to obtain a surface free of organic solvents, chemical reagents, and films of complex composition not interacting with solvents. Since the composition of pollutions is different and is often not known, sputtering by argon ions is the most effective method for removing the hyperfine surface layers [7].A promising method for directional modification of the surface of polymers and fibrous materials, as noted in [8], is ion implantation, since, as the dose is accumulated, processes radically differing in their nature proceed, and they can be controlled by varying the energy and mass of the ions being implanted. In [9], it was suggested to use the ion-beam method to modify the surface of track diaphragms in order...

An overview of new oxidation methods for polyacrylonitrile-based carbon fibers

“…PAN has tended to be the most widely used precursor for high-performance carbon fibers [16][17][18][19][20][21][22]. Most useful carbon materials have also been modified by several surface treatments, such as anodic oxidation [23], plasma [24,25], oxyfluorination [26], ozonization [27], or fluorination [28], Ar ion beam [29][30][31], several metal coatings [32][33][34], chemical treatments [35,36]. These treatments enable or enhance function and performance in real industrial applications, including adsorption [37], toxic removal [38,39], catalysis [40][41][42], adhesion or composites [43,44], electrochemistry [45][46][47], and so on.…”

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