Recuperación de fibras a partir de residuos de materiales compuestos por tratamiento térmico: optimización experimental y matemática de las variables de operación

Carbon and glass fibers can be recovered from residual fiber-reinforced composites through thermal treatment. This treatment consists of heating the material in an inert atmosphere (pyrolysis) to a temperature high enough to decompose the polymeric resin and the subsequent oxidation of the carbonaceous products generated in this decomposition in the presence of air. The result of this treatment is the complete elimination of the resin and the recovery of the fibers, which maintain good physical-chemical properties. In this work the statistical design of experiments has been used to determine the influence that the three main operation variables involved in the recovery of fibres by thermal treatment (pyrolysis temperature, oxidation temperature and oxidation time) have on the removal performance of polymeric resin. The experimental strategy used is the complete factorial design 2k, where k=3, the operation variables studied. The strategy has been applied to waste coming from the wind and aeronautical sectors, both cured pieces and expired pre-pregs, and reinforced with carbon fibers and glass fibers. With the results obtained in the thermobalance experiment, the relative importance of the variables studied for each one of the samples has been determined. Besides, the mathematical equations that allow predicting the resin elimination yield depending on the value taken by these variables have been defined.