Mechanical properties of recycled glass fibre reinforced nanoclay/unsaturated polyester composites

Abstract

The purpose of this study is to study the effects of montmorillonite (MMT) nanofiller on the mechanical properties of glass fibre recyclates (rGF) reinforced unsaturated polyester (UP) composites. Alumina-silicates nanoclay such as MMT can improves the mechanical performance of polymeric composites. This study uses the mechanical recycling process to grind the GFRP waste into recyclates. MMT nanoclay was dispersed into UP using ultrasonicator. Different weight percentage of rGF at 25 wt.%, 30 wt.% and 40 wt.% were mixed in UP-MMT resin and formed into composites plate using compression moulding. Preliminary study shows that, the tensile strength of 25 wt.% raw rGF-UP composites was approximately 50% lower than of UP. Therefore, raw rGF was sieved into coarse and fine grade to improve the tensile properties of the composites. Compared to raw rGF, sieved rGF has better tensile strength due to better fibre distribution of rGF and uniformed fibre length. Coarse rGF composites which contain relatively larger aspect ratio (longer fibre length) have better tensile properties than fine rGF. The inclusion of MMT nanofiller in polyester resin enables the tensile strength of the composites to increase. For example, the tensile strength of 40 wt.% fine rGF-3 wt.% MMT hybrid composites is higher by 14% than the non-hybrid 40 wt.% fine rGF. Scanning electron microscopy shows good fibre/resin adhesion for MMT below 3 wt.%. While at 5 wt.% MMT, the UP resin becomes degraded and developed poor adhesion of resin to the recyclate fibres.