Despite the excellent reinforcing effect, the use of carbon fibres has not increased as expected at the expected rate. Therefore, improvements in this area are aimed at lower production costs lower production costs. The same is also true for the recycling of carbon fibres. Continuous improvement glass fibres are also being developed. A new glass fibre is also a competitor to carbon fibre, since its tensile strength similar, but the electrical and thermal insulation properties of products reinforced with it are glass fibre products. The performance of reinforced plastics is matrix polymer and the coupling agents that enhance the adhesion between the reinforcing fibre and the additives, which are being continuously developed by additive companies.