Advances in the production of transparent fiber reinforced thermoplastics

The development of fiber reinforced plastics (FRP) in the 1950s has revolutionized the lightweight construction and especially the transport sector. Thus, the dominating materials such as steel or aluminum were partially replaced by FRPs in automotive and aerospace applications. Until today the success of FRPs did not spread to transparent materials. Nevertheless, the use of transparent FRPs as a window replacement would result in a significant weight reduction. Lightweight, transparent FRPs with high mechanical properties and acoustic damping could substitute side windows and windshields of cars as well as enhance the stability of airplane windows making them lighter and bigger. Additionally, frame constructions for accommodating the windows can also be reduced, which entails considerable weight savings in the vehicle. Because the industrially used FRPs with high specific strengths are not transparent, the use as a window glass replacement is not possible. To solve this deficit, transparent, high-strength FRPs are developed at the Institute for Textile Technology of the RWTH Aachen University. For this purpose, suitable and economic manufacturing processes are designed which combine a glass fiber and a matching thermoplastic matrix. In order to achieve a transparency comparable to window glass the refractive indices of these materials are equalized. This technical paper will focus on the development of transparent FRPs. This includes the material selection and adjustment, the process development as well as the manufacturing of a first demonstrator. The characterization of the newly developed transparent FRP will be compared to existing transparent materials with regards to its advantages and disadvantages as well as its application in the mobility sector.