The influence of ultraviolet radiation on the optical properties of glass fibre reinforcements for polyurethane matrix composites

Polyurethanes represent one of the most frequently used polymeric matrixes in composites. Although there have been many studies focused on the weather resistance of polyurethanes, this important property is unheeded during the reinforcing phase. In this article, the effects of ultraviolet (UV) radiation on the changes in optical properties of commercially available glass fibre reinforcements containing various polymeric binders used as compatibilising agents for the polymeric matrix in the final composite products were studied. The standardised experiments were performed using accelerated ageing equipment, q-lab ultraviolet tester, in dry mode. Chemical modification of the binder in the form of polyesters or silanes by UV irradiation was studied using Fourier Transform–infrared spectroscopy. Changes in the optical properties caused by the degradation processes of polymeric components due to UV irradiation were evaluated based on colour changes in the examined samples using the yellowness index; statistical evaluation of the data obtained was conducted with an Anderson–Darling test of normality and an ANOVA test. It was demonstrated that both the amount of the binder and the glass fibre reinforcement's construction play a more important role than the chemical structure of the binder. © 2019 The Authors. Coloration Technology © 2019 Society of Dyers and ColouristsTechnology Agency of the Czech Republic [TH01011438]; Ministry of Education, Youth and Sports of the Czech Republic - Program NPU I [LO1504]; European Regional Development Fund (ERDF)European Union (EU); National Budget of the Czech Republic [CZ.1.05/2.1.00/19.0409