The effect of coupling agents on the mechanical properties of carbon fiber-reinforced polyimide composites

Abstract

Carbon fiber (CF)-reinforced polyimide (PI) has been widely used in many engineering fields because of its high specific strength and stiffness. However, PI does not adhere well with CFs because it has low free surface energy. In addition, high viscosity in the melted phase causes poor impregnation. In this study, surface treatment methods, that is, coupling agents (CAs) with plasma treatment on CFs, were applied to increase the interfacial strength between the CFs and the PI matrix. The modified CF surfaces were analyzed by X-ray photoelectron spectroscopy and scanning electron microscopy. To analyze the effectiveness of the surface treatment method, the interlaminar shear strength (ILSS) was measured using the three-point bending test. From the test results, the ILSS of the specimens treated with the silane CA after the plasma treatment increased by 48.7% compared with the untreated specimens.

Design, Manufacture, and Performance Testing of Extrusion–Pultrusion Machine for Fiber-Reinforced Thermoplastic Pellet Production

“…Those methods aim to improve the number of reactive groups or increase the fiber's surface roughness to enhance the bonding quality with the matrix. Fiber treatment using a CA is a standard method among the other [11]. Silane CA forms an alkoxysilane group that can be reacted with the hydroxyl group after hydrolysis.…”

Improvement of mechanical and physical properties of carbon fiber-reinforced polyamide composites by applying different surface coatings for short carbon fiber

“…21 –25 There is no doubt that increasing compatibility and interfacial adhesion between fiber and polymer levels up these properties of PA6-based composites. 26 –29…”

The effect of surface treatment of CF and graphene oxide on the mechanical properties of PI composite

“…However, applications of CFs-reinforced polymer composites are restricted owing to the poor interfacial adhesion between CFs and matrix resin, which is attributed to the nonpolar, low surface energy and chemically inert surface of CFs. 8,9 Fiber-reinforced polymer composites exhibit strength properties that make them a favored class of materials for a wide range of applications where the reinforced fiber composites fail to deliver the desired results. Another special feature of such reinforcement is their ability to drape or conform to curved surfaces without wrinkling.…”

“…Significant efforts are currently devoted to the development of nanoparticle/polymer composite motivated by the processing of individual particles into a solid material for device integration or by the design and control of polymer properties. 8,9 Improvements of thermal, mechanical, or electromagnetic behavior among others have given rise to interesting studies. 10 Only a few weight percent of inorganic particles dispersed in the polymer matrix are necessary to observe a modification of mechanical properties.…”