Effect of various chemical modifications of date palm fibers (DPFs) on the thermo-physical properties of polyvinyl chloride (PVC)–high-density polyethylene (HDPE) composites

Abstract

Algerian palm groves, a key component of oasis ecosystems, generate significant volumes of natural waste. In the present study, leaflet and rachis derived date palm fibers (DPFs) produced from the pruning of date palm trees were used as an effective filler to reinforce composites consisting of polyvinyl chloride and high-density polyethylene (PVC-HDPE) (20:80). Composites with an untreated and treated DPFs loading of 30 wt.% were prepared using a twin-screw extruder and compression molding. The DPFs surface was modified using various treatments, including NaOH, 3-aminopropyltriethoxysilane, combined alkali-silane, bleaching with NaClO2, and H2O2+HNO3. The successful surface modification of the DPFs, including delignification and the extraction of cellulose microcrystals (CMCs), was verified using infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermogravimetric analysis (TG). The results revealed an improvement in the morphological, thermal, mechanical, dynamical-mechanical, rheological, and water uptake performance of the composites with the addition of the modified DPFs. It was concluded that it was the CMCs that primarily enhanced the thermo-physical properties of the PVC-HDPE composites, making them suitable for several industrial applications.