DOI: https://doi.org/10.55373/mjchem.v26i5.125

Keywords: Polypropylene; high-density polyethylene; polyvinyl chloride; fly ash; recycled thermoplastic composite; mechanical properties; thermal properties

Abstract

Recycled thermoplastics such as polypropylene (rPP), high-density polyethylene (rHDPE), and polyvinyl chloride (rPVC) are reused to minimize the consumption of plastic. Addition of fillers to recycled thermoplastics during recycling process may improve its mechanical and thermal properties. In this study, fly ash (FA) was used as filler and added to recycled thermoplastics for preparing composite, whereby the mechanical (tensile modulus, elongation at break) and chemical properties were determined. The rPP, rHDPE, and rPVC were mixed with FA at the weight ratio range of 100:0 to 80:20 in a twin-screw extruder machine at 180−230 ℃, a rotation speed of 60 rpm and hot compressed at 175−200 ℃ for 5−10 min. The highest tensile strength of FA-thermoplastic composite was recorded at 10−15 wt% of FA content. A similar trend was observed for tensile modulus and elongation at break. It is due to the uniform dispersion of FA particles in the recycled thermoplastic matrix that influences effective stress transfer from matrix to filler. However, an FA content greater than 15 wt% decreased the tensile properties of composites. Possible formation of voids from excessive FA content may have caused poor interfacial adhesion and contributed to a poor stress transfer from the recycled thermoplastic matrix to the FA filler. However, FA-recycled thermoplastic composite has good mechanical properties for construction applications.