Controlling of the Interfacial Shear Strength between Thermoplastic Resin and Carbon Fiber by Adsorbing Polymer Particles on Carbon Fiber using Electrophoresis

Carbon fiber reinforced plastics are one of the commonly used composite materials in construction of materials in transporter and sports equipment due to their light and strong characteristics.

Dr. Tetsuya Yamamoto and colleagues from Nagoya University in Japan developed a technique to control the interfacial adhesion between the carbon fiber and the thermoplastic resin. They investigated the adsorption of poly (methyl methacrylate) particles on the surface of carbon fibers by electrophoresis and the fragmentation testing using a tensile test apparatus to evaluate the surface adhesion between the modified carbon fiber and the thermoplastic resin. The research work is now published in peer-reviewed journal, Composites: Part. A.

The authors introduced an ionic water-soluble initiator so as to enable soap-free emulsion polymerization and maintain the dispersion stability of the polymer colloids in water. As the aim of the researchers, to control the surface adhesion between carbon fibers and the resin in carbon fiber reinforced plastics, polymeric particles were adsorbed on the carbon fiber surfaces using electrophoresis in polymer colloids.

They found that increase in the amounts of poly (methyl methacrylate) particles adsorbed on the carbon fiber, led to the interfacial shear strength increase and a constant value was obtained. The pointed out that multi-layers formed at applied voltages higher than 25 V is not effective in enhancing the interfacial affinity between the carbon fiber and the resin. On application of heat at about 200 °C, the poly (methyl methacrylate) particles melt and deform on the carbon fiber, but with an increase in temperature and pressure, the surface adhesion between the modified carbon fiber and the thermoplastic resin were strengthened.

This study developed a technique for controlling the interfacial adhesion between the carbon fiber and the thermoplastic resin. The technique shows an improved interaction and a strengthened surface adhesion between the carbon fiber coated with particles and the poly (methyl methacrylate) resin. The present method will be a fundamental technique to enhance the mechanical properties of carbon fiber reinforced thermoplastic (CFRTP).