The Effects of Recycled Polypropylene/Wood Flour (r-PPIWF) Composites with and without Coupling Agent on Mechanical Properties

Plastic and wood have been indirectly causing global warming and developing domestic waste. Plastic is massively produced every day, so it contributes in high municipal waste generation rate and it is non-biodegradable. With depleting number of trees and forests, wood wastes are either burned or disposed which resulting in extra consumption, and pollution of nature. Therefore, by combining them into Wood Plastic Composite, we can recycle and reuse the product to replace current landscaping and furniture products. The main objective of this project is to study effects of different compositions on the mechanical properties of r-PP/WF composites and investigate the effects of coupling agent on the mechanical properties. Therefore, the scope of this project was focused on finding the composition of rPP/ WF that produces the best mechanical properties and investigating the effects of coupling agent on the composites. Thus, the methodology started with drying the WF, sieved the WF, granulated the r-PP, mixed r-PP and WF in the twin screw co-rotating extruder machine, then the pellets were hot-pressed in compression molding machine to create 20 em x 15 em x 0.4 mm plates, then cut into ASTM 0638 (type 1), ASTM 790 and ASTM 256 samples before proceed with the standard tensile, flexural and Izod impact testing. Then, the fractured samples were examined under SEM to see its microstructure. From the mechanical testing, the tensile strength of the composite reduced about 15% - 49% if compared to r-PP, but with coupling agent, the tensile strength improved 16% - 45%. While for flexural strength, the composites reduced 5% - 45% of its strength if compared to r-PP but improve 29% - 49% with coupling agent. On the other hand, flexllfl\1 modulus improved up to 135% if compared to r-PP and the improvement by adding coupling agent is up to 80%. The impact strength also reduces 26% - 38% if compared to r-PP and slightly improvement done by coupling agent about only 2% - 12%. The best composite is 30% of WF, 65% of r-PP and 5% of FB. The microstructural analysis done by using SEM explains the mechanical properties behaviour. As a conclusion, the mechanical properties reduced probably due to processing techniques and the improvement done by coupling agent. The objectives of this project were achieved and this project proves that r-PP/WF composites are one of comparable alternative material for furniture and landscaping purposes