Revitalizing high-density polyethylene (HDPE) waste: from environmental collection to high-strength hybrid yarns

Plastic products are used in large quantities. However, the fact that plastics do not degrade in nature for many years causes environmental pollution. Addressing this issue, the study focuses on recycling the widespread high-density polyethylene (HDPE) plastic waste. In this study, HDPE waste was collected randomly from the environment, mirroring real-world scenarios. Then, the waste was transformed into granules. Afterward, washing and drying processes were carried out. HDPE filaments of different linear densities were successfully produced from the waste plastic granules. Tensile tests revealed that the breaking strength of the filaments from waste plastic was lower than that of virgin HDPE filaments, highlighting the challenges of recycling. Hybrid yarns were formed by twisting the filaments with cotton yarn to improve the mechanical properties of the filaments from waste plastic. Remarkably, statistical analysis demonstrated that the breaking load values of the hybrid yarns from waste plastic were statistically equivalent to those made from virgin polymer. This outcome indicated that the hybrid yarns made from waste HDPE plastic were as strong as those made from virgin HDPE polymer. In addition, both hybrid yarns exhibited a breaking load 36% higher than the reference extra-twisted cotton yarn. The hybrid yarn formation made filaments produced from waste plastic a valuable component of the high-strength hybrid yarn. Overall, this study shows that recycling HDPE plastics can lead to the production of high-strength hybrid yarns, which can contribute to reducing plastic waste pollution.