Preparation process of carbon fiber composites (Part 1)
Carbon fiber composite material is a kind of high performance composite material, which is composed of carbon fiber and resin matrix. It has the advantages of high strength, high modulus, low density, corrosion resistance, fatigue resistance, etc., and is widely used in aerospace, automobile, sports equipment and other fields. This paper will be divided into the following five main steps to introduce the preparation process of carbon fiber composite materials.
1. Pretreatment of carbon fiber Before preparing carbon fiber composite materials, carbon fiber needs to be pretreated to improve its surface activity and compatibility with the resin matrix. There are many pretreatment methods, such as oxidation treatment, anodic oxidation treatment, plasma treatment and so on. Among them, oxidation treatment is one of the most common methods. Oxidation treatment is done by exposing carbon fiber to air or oxygen at a certain temperature and time to form an oxide film on its surface. This layer of oxide film can increase the surface roughness and specific surface area of carbon fiber, so as to improve its bonding strength with the resin matrix. The conditions of oxidation treatment are usually 200-400°C, 1-10 hours.
2. Preparation of resin matrix Resin matrix is an important part of carbon fiber composite materials, it can be divided into thermosetting resin and thermoplastic resin two categories. Thermosetting resin refers to the resin that will undergo curing reaction during heating to form a three-dimensional network structure, such as epoxy resin, polyester resin, phenolic resin, etc. Thermoplastic resin refers to a resin that can be softened or melted during heating, such as polyethylene, polypropylene, nylon, etc. When preparing the resin matrix, it is necessary to select the appropriate resin according to the performance requirements of the carbon fiber composite material and the use environment, and mix the resin and the curing agent evenly according to a certain proportion. Mixing methods include mechanical stirring, ultrasonic stirring, vacuum stirring and so on. The mixed resin matrix needs to be defoamed at a certain temperature to remove the bubbles in it.