Fiber and resins

A fiber-reinforced polymer composite consists of reinforcing fibers and a polymer matrix. A variety of fiber and polymers can be used in composite materials, depending on the application and the required specifications.

Polymer composites can be classified according to the type of reinforcing fiber. Fibers are commonly classified as ceramic, natural or polymeric. Carbon fibers combine a very high stiffness with a very low weight, but also have a brittle fracture behaviour and are more expensive. Polymeric fibers on the other hand combine a ductile behaviour (improved impact performance) with a very low weight, but have a lower stiffness.

The specifications of the final product and the exact loading conditions determine which type of fiber is best suited for the specific application. Before production of the composite part, the reinforcing fibers are mostly arranged in fiber preforms for ease of handling. Typical fiber preforms are unidirectional tapes, non-crimp fabrics and woven, braided and knitted fabrics. Each preform type has its own specific pattern and advantages. Several fiber types can also be combined into one polymer composite, to form a so-called hybrid composite. This type of composite is only used in very specific cases.

Polymer composites can also be divided into two classes according to the resin type. Thermoset composites are based on thermoset resins, consisting of one fully cross-linked netwerk. During composite production, these resins transform from a liquid to a solid state by cross-linking with a curing agent. The most common thermoset resins are epoxy, polyester, polyurethane and phenolics. Thermoplastic composites on the other hand are based on thermoplastic polymers. These polymers consist of separate molecules instead of one fully cross-linked netwerk. During composite production, the solid polymer is heated and pressed between the fibers. The best known thermoplastic resins are polypropylene and polyamide. The choice of type of resin has a big influence on the composite production method.

REIN4CED works with all fiber types and has experience with both thermoset and thermoplastic composites. For each individual application, REIN4CED considers all possible fiber-resin combinations and makes a final selection based on the predefined specifications.