EFFICIENT PREPREG RECYCLING AT LOW-TEMPERATURES

When manufacturing fibre reinforced plastics engineers are still confr onted with a lack of experience concerning efficient recycling methods for prepreg cutting waste. Normally, the prepregs are cured and subse quently milled to use them as a filler material for polymers. However, this method is expensive and it is difficult to find applications for the milled FRP. An alternative method to recycle CFRP prepregs will b e presented in this paper. Cutting the uncured prepreg waste was done by means of a saw mill which was cooled down to low temperatures. Work ing temperatures of -30 degrees C are sufficient to harden the uncured resin and to achieve cuttable prepregs. Furthermore, post-curing duri ng the cutting process is avoided with this technique. The result is a 'cotton'-like matted structure with random fibre orientation and fibr e length distribution, Subsequent curing was done by means of a press and an autoclave, respectively. It will be shown by means of tension a nd bending tests that low-temperature cutting of uncured prepregs is a way to partly conserve the high valuation of FRP during recycling. Fu rthermore, it offers possibilities for various applications. (C) 1998 Elsevier Science Ltd. All rights reserved.