Effect of different waste filler and silane coupling agent on the mechanical properties of powder-resin composite

This study reports an innovative pathway for successfully synthesizing composite panels using various waste input. For this purpose, seven types of powder from waste or widely available filler i.e. Quartz off-cut, sand, waste seashell, dolomite, limestone aggregates, concrete waste and limestone dust were used. The study aims to assess the effectiveness and mechanical properties of the various waste powder in the production of powder-resin composites. The panels were then compared with the novel polymeric glass composite (PGC) in the previous study (Heriyanto et al., 2018). Following the same procedure in PGC, the filler was individually grounded to 64–108 μm and chemically treated with amino silane coupling agent (CA). The powder filler (untreated or treated) is then mixed with the resin binder with a ratio of 80/20 respectively, followed by hot pressing the mixture at the pressure of 550 bar at 65 °C for 1 h. The final composite slab is then further cut for mechanical testing. It was found in the study that when CA was not added, surface roughness of the powder particles affected the flexural strength of the final panel significantly. High surface roughness particles such as in Quartz, sand and seashell adhere effectively with the resin binder which led to higher strength. On the contrary, other factors like smooth particle morphology in glass, dolomite and limestone as well as porous structure in concrete and clump of very fine powder in limestone dust degrade the strength of the final panels. With CA addition, adhesion between resin and powder filler were improved significantly. Flexural strength after the CA treatment was found to be much affected by particle characteristics. Silica-based panels i.e. quartz, sand and glass which consist of high strength and hardness of silica particles perform better compared to that of calcium carbonate-based panels. Compression strength, toughness, stiffness, scratch resistance, density and water absorption were also reported in this study. The properties of all the treated panels are found to be comparable, or if not, much better than natural stones. These new approaches of using waste filler in powder - resin based composites can be a new alternative to produce green materials that deliver economic and environmental benefits.