The utilization of waste plastic bag, especially as a matrix for wood plastic composites, is expected to reduce the environmental problems throughout the world caused by its use. Wood plastic composites were manufactured via melt mixing of chopped or pelleted waste plastic bags, sawdust and polyethylene grafting maleic anhydrate (MAPE) according to Extreme Lattice Mixture - Design of Experiment (DoE). The effects of concentrations and reprocessing of waste plastic bags on flexural modulus of elasticity and strength of composites were analyzed. In general, flexural modulus of composites from chopped and pelleted waste are increased but still below the value of SNI 8154–2015. Moreover, the flexural strength of the resulted composites from chopped waste also increased than that of the pelleted one. Some of the formulas of composites from chopped waste met the value required by SNI 8154 – 2015. On the contrary, the flexural strengths of composites from pelleted waste are decreased than that of the virgin one. This is probably due to the existence of interaction between pelleted waste and sawdust that prevented the waste plastic to perfectly melted, hence acted as stress concentration sites. Furthermore, the resulted composites were optimized for flexural modulus using response optimizer plot in order to achieve modulus 2000 MPa that required by the standard. However, the optimized flexural modulus of composites from chopped and pelleted waste was in the range of 1500 MPa, which is far below the standard. Therefore, reprocessing of chopped waste into pellets is not necessary due to inferior properties of composites from pelleted waste than that of the chopped one.
Waste plastic bags (WPB) from high density polyethylene (HDPE) have been reprocessed for many applications. However, it is limited to be used as wood plastic composites (WPC) for building applications as the decrease of mechanical properties. This research examined the optimal composition of WPB that can be added to WPC and complied with Indonesian Standard (SNI) 8154 – 2015. Samples were produced according to extreme vertices mixture design using twin screw extruder (TSE). The materials were WPB bounded in the range of 0 to 20 wt%, sawdust at 50 to 70 wt%, neat HDPE at 30 to 50 wt%, and HDPE grafting maleic anhydride (PE-g-MA) at 0 to 10 wt%. The compositions were optimized to obtain desired flexural modulus and strength as required on SNI standard. The optimized formula was then reproduced and characterized to analyze its water content, density, swelling, and formaldehyde content. The results showed that the optimum formula was predicted at 3 wt% of WPB, 50 wt% of sawdust, 37 wt% of neat HDPE, and 10 wt% of PE-g-MA, giving 2111 MPa and 27.3 MPa of predicted values that above the minimum requirement for WPC material (2000 MPa for modulus, 20 MPa for strength). Meanwhile, the modulus and strength of verification sample were 2173 MPa and 25.7 MPa. Further analysis on the other properties showed 0.6 ± 0.1% of water content, 1.7 ± 1.4% of swelling, and 0.015 ± 0.000 mg/L of formaldehyde that lower than maximum specifications, and 1.13 ± 0.01 g/cm3 of density that above minimum the requirement.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.