Reused Carbon Fibre as Reinforcing Filler in Palm-Based Polyurethane Composites

Abstract

The loading effect of recycled carbon fibre at 5, 10, 15 and 20 wt.% on the mechanical strength of the palm-based polyurethane (PU-rCF) was investigated. The recycled carbon fibre (rCF) from glycolysis of the carbon fibre-epoxy mat (CFRP) was obtained. The glycolysis was conducted at 180–190 °C under atmospheric pressure and catalysed by 1.9 wt.% NaOH in 80% aqueous medium. The rCF was analysed by FTIR spectroscopy analysis and SEM observation. Clean fibre without residual traces was obtained. The rCF was then incorporated into palm-based polyurethane to form composite panel (PU-rCF). The addition of rCF improved the mechanical strength of the composite. The impact strength increased more than 3 folds from 0.6 kJ/m2 to 3.8 kJ/m2 while the flexural strength increased from 43 MPa to 61 MPa. The shore D hardness index was at the highest (72) with maximum rCF loading of 20 wt.%. As expected, the FTIR spectrum of the PU-rCF indicated the absence of chemical interaction between PU and the rCF. The strong physical interaction between the rCF fibre strands has decreased the brittleness of the PU and increased the mechanical strength of the composites.