The mechanical properties of CFRP depends mainly on the matrix, the mechanical properties of common epoxy resin , the surface properties of carbon fiber, and the nature of the fiber and the matrix bonding interface, and the performance of the matrix and fiber surface properties directly related to the interface bonding and adhesive performance, the following described from two aspects:
1、Matrix: CFRP commonly used epoxy resin as matrix, its good adhesion, excellent mechanical properties, but the general type of epoxy resin after curing, brittle hard, shock resistance is poor, poor heat resistance. At present, the toughening method is relatively mature will cure before can compatible rubber and epoxy resin dissolved in resin, curing, rubber to precipitate, a two phase structure. At present commonly used are RLP type rubber, small molecular weight (1000 ~ 10000), with epoxy resin with reaction of functional groups, so as to produce strong chemical junction. We can make the epoxy resin matrix containing aromatic ring main chain structure and increase the crosslinking density method, such as epoxy resin to improve use temperature and thermal stability, at the same time improve its and adhesive properties of carbon fiber.
2、The carbon fiber surface properties: Without the surface treatment of carbon fiber surface is smooth, small friction coefficient, surface presents abhorred liquidity, leading to poor wettability with matrix, bond is low, the interlaminar shear strength (ILSS) of composite materials, interfacial shear strength (IFSS) are low, can not meet the actual demand. Commonly used the surface treatment of oxidation and coating processing, electrical aggregation and the electroplating treatment, plasma treatment and so on. Using the method of electrochemical oxidation, anodic oxidation surface treatment, moderate reaction, easy to control, the treatment effect is good. After surface treatment of carbon fiber with effective scanning tunneling electron microscope (STM) surface analysis found that the edge of the surface of graphite layer of oxidation, large-area edge active point number increase, is more advantageous to the uneven surface and bonding of matrix, and the shear properties of composite materials. At the same time, its surface can increase, significantly improved the wettability between carbon fiber and matrix, the contact Angle decreases, and surface present a lyophilic sex. In addition, after surface treatment, its surface appear a large number of hydroxyl, carboxyl, quinones and pyranoid ketone functional groups, improve the polarity of the carbon fiber surface, increase with the wettability between substrate and adhesive. Carbon fiber reinforced polymer (CFRP) has been quite widely in the field of aerospace and defense force. Such as CFRP can be used in the manufacture of artificial satellite support, satellite antenna, the wing of the shuttle, the rocket's crater, strategic missile final boosters, the robot's shell, etc. Aircraft to meet the light, strong, strong resistance to distortion, a Boeing 767 aircraft, its fuselage drive door, landing gear doors, hood, main wing, the top of the flap, the back of the tablet and other parts are made from carbon fiber and CFRP, total more than 1 ton. Automobile manufacturing, automobile shell, joystick, flake spring made of CFRP, can make the total weight of the car to reduce 70%. Sports leisure aspects, fishing rod, tennis rackets, skis, racing, pole high jump are made of CFRP, greatly enhance the performance. Frame structure of the high-rise buildings by using CFRP can rise to enhance, increase, reduce the load of building base, and so on, the other party # 40 # in December 2001, such as bicycle beam, the sword of rapier loom belt, under heavy load of elevated intersection beam, column, etc are made using CFRP available.