Chemical recycling of carbon fiber reinforced plastic using supercritical methanol

摘要

Advanced chemical recycling of carbon fiber reinforced plastic (CFRP) was developed using supercritical methanol. In this method, the thermosetting epoxy resin in CFRP was converted to a thermoplastic resin by the selective decomposition of the bridged structure by supercritical methanol at 270 °C and 8 MPa for 90 min and the resin dissolved in supercritical methanol. On the other hand, the carbon fiber was fully recovered from CFRP without the plastic component and it had no thermal damage. The bridged structure in the epoxy resin could be formed again by adding a cross-linker to the recovered thermoplastic resin and the thermosetting resin was reproduced. This was the first attempt on the recycling of thermosetting epoxy resin. However, in order to maintain the strength of the recycled epoxy resin to that of virgin epoxy resin, the proper ratio of the recovered thermoplastic resin to virgin epoxy resin was determined. The recovered carbon fiber from CFRP maintained the shape of the plain fabric and the reduction of the tensile strength was less than 9% compared with the virgin one. The recovered carbon fiber could be used to make a recycled CFRP with epoxy resin and cross-linker, the strength of which was close to that of virgin CFRP.