Mechanical and thermal properties of recycled high-density polyethylene/bamboo with different fiber loadings

Abstract

Abstract The use of recycled polymers in natural fiber-based composites provides an additional competitive advantage with their environmentally friendly properties. This study utilizes recycled high-density polyethylene (r-HDPE) as a composite matrix with bamboo fiber reinforcement that has been treated with an alkaline process. This study aims to analyze the mechanical properties and thermal properties of r-HDPE composites manufactured by extrusion molding with different bamboo fiber loadings. The specimens were subjected to tensile and impact testing for evaluating the mechanical properties. Thermogravimetric analysis (TGA) was performed to identify thermal stability, while the differential scanning calorimeter (DSC) was used to analyze the melting point phase of each specimen. This study indicated that the tensile strength of the composites decreases with increase of fiber fraction. The composite with 0% bamboo fiber showed the highest tensile strength of 8.3 N/mm2, while the lowest tensile strength is shown by the composite with 30% of bamboo fiber. Scanning electron microscopy showed porosity, pull-out, fiber cracking as the indicators for the material failure during tensile testing. From the impact test, it can be shown that the composite with 10% bamboo fiber records the highest impact strength at 37.7 J/m2. The TGA indicated high thermal stability of r-HDPE composites with 10% of bamboo fiber at 362.4°C temperature. A similar result was also exhibited from the DSC test, where the material with 10% fiber loading shows a big change in melting phase temperature. This research evidences the effect of bamboo fiber in increasing the impact strength and thermal stability of recycled HDPE matrix. This material could be the alternative for light-bearing applications such as automotive indoor components.