Chemical recycling of glass fibre reinforced composites using subcritical water

A hydrolysis process is applied to degrade an unsaturated polyester resin based on DCPD (dicyclopentadiene) and crosslinked with styrene, as the matrix of a composite material reinforced with long glass fibres. Subcritical conditions of water (200 °C < temperature < 374 °C and pressure < 221bars) were chosen regarding the involved chemistry for the case of simple esters. Several experiments were realised to measure the effects of the process parameters on the efficiency of hydrolysis, on the quality of the recovered fibres and finally on the nature of the recovered organic products. A washing of the fibres is necessary and appears to be an important step of the process realised in batch conditions. The identification of the recovered organic products indicates that monomers of the resin are obtained but also that secondary reactions occur during the hydrolysis process.