Composites are a class of materials created by the systematic combination of two or more materials. Usually, fine particles or fibres of one material are embedded into another, the so-called matrix. Thus, the individual properties of the starting materials can be combined to a composite with a customised and unique set of material properties.
Starting in the 60’s, lightweight construction has increasingly relied on fibre reinforced plastics. High-strength carbon, glass or aramid fibres result in composites with extraordinary high specific stiffness and strength. Through an adept choice of materials the electrical, magnetic and thermal properties may be tailored to specific needs. Typically, the production processes allow for the integration of sensors and actuators turning such composites into smart materials.
The most crucial part in composite manufacturing is to combine the constituting components to a consolidated part with the least amount of flaws possible. State-of-the-art matrices are thermoset polymers, e.g. epoxies or polyesters. Due to their low viscosity such chemically reactive resins can readily wet and enclose the reinforcing fibres. These composites are well suited for small series production and are well established in the aerospace industry.
One major drawback when using thermoset resins is the inherent curing time required by the chemical reaction. Also, the reactive nature of thermosets demands for special safety precautions in order to prevent impacts on occupational health and the environment.
In contrast, thermoplastics consist of completely non-toxic polymers and are merely heated and resolidified during moulding. This process produces virtually no emissions of VOC. Depending on part dimension and geometry, thermoplastic composites make cycle times of a few seconds possible, a fact that leads to lower manufacturing prices per part. When compared to thermosets, thermoplastics generally offer higher toughness, better chemical resistance, inherent weldability and direct recyclability, as well.
The comprehensive technological development by next composites makes serial production of complex and structurally challenging thermoplastic composite parts a highly competitive alternative to conventional thermoset manufacturing technologies.