One of the main approaches to enhance the mechanical properties of engineering polymers, especially high-density polyethylene (HDPE), is the use of various additives to the base polymer matrix. This study investigates the effect of recycled polyethylene terephthalate microfibers (rPET-MF), Nano-clay, and maleic anhydride-grafted PE (MA-g-PE) on the mechanical properties of HDPE hybrid composite in compression molding processes. Different HDPE composites with these additives were prepared based on the Taguchi L9 orthogonal array at three different levels. The mechanical properties of the samples were evaluated through tensile and impact tests. The results showed a significant improvement in the tensile strength and impact resistance of the composites, especially with the addition of Nano-clay and rPET-MF. The impact strength increased from approximately 8.6 kJ/m² for neat HDPE to 24.5 kJ/m² for the optimized hybrid composite, while the tensile strength improved from about 9 MPa to 27 MPa. Analysis of the Taguchi results showed that in the tensile test, rPET-MF had the greatest effect, followed by Nano-clay and MA-g-PE. Conversely, in the impact test, Nano-clay showed the greatest effect, and rPET-MF and MA-g-PE ranked second and third, respectively. These findings suggest that the optimal combination of these additives could provide a practical approach to develop HDPE composites with improved mechanical properties. This advancement could have wide applications in various industries including packaging, automotive, and construction.
