Experimental Study of Pine Needle Forest Waste and Recycled Polypropylene in Developing Sustainable Hybrid Jute Composites

Abstract

This study experimentally investigates the development and properties of hybrid composites utilizing forest waste (pine needles) and recycled polypropylene (rPP) reinforced with jute woven fabric. The primary objective is the valorization of pine needle waste mitigating forest fire risks and plastic pollution through composite material development. Five composite laminates were fabricated with constant jute content (10 wt%) and an rPP matrix, incorporating varying pine needle loadings (10, 20, 30 wt%). Results demonstrate a significant 40% reduction in virgin plastic content. However, this reduction incurred a trade-off: flexural strength decreased by 40.77% and impact strength (Izod/Charpy) by 35.35% compared to the baseline rPP/jute composite. Thermogravimetric analysis revealed the thermal stability of the hybrid composites remained significant and comparable to recycled PP. X-ray diffraction (XRD) analysis indicated that incorporating short pine needles substantially increased the crystallinity of the composites. Scanning Electron Microscopy (SEM) examination of fracture surfaces identified the dominant failure mechanisms as poor interfacial adhesion between the pine needles and the rPP matrix, coupled with the inherent low strength of the pine needles. The developed composites show potential for nonstructural applications where sustainability and waste valorization are prioritized.