Comparative review of fiber treatments,processing,and tensile strength and modulus of hemp-polymer composites

Abstract

Hemp fiber-reinforced polymer composites have garnered attention as sustainable alternatives to synthetic materials due to their low density, cost-effectiveness, reduced equipment wear, and favorable mechanical properties. Unlike studies that primarily focus on composite production, this paper also explores how planting, fertilizing, harvesting, retting, decortication, and cleaning affect fiber strength and, in turn, influence the final composite properties. This review examines a variety of fiber treatment methods and processing techniques used for hemp-polymer composites. Treatments, including both physical and chemical methods, aim to improve fiber compatibility with polymer matrices, enhancing the composites’ tensile properties. The review covers a range of polymer matrices, such as thermoplastics (e.g., polypropylene, polylactic acid), thermosets (e.g., epoxy, polyester), and biodegradable options (e.g., polyhydroxybutyrate, wheat gluten), assessing their performance with treated and untreated hemp fibers. Results indicate that fiber treatments, such as alkali processes and coupling agents, significantly improve fiber-matrix adhesion, enhancing composite performance. The paper centers on tensile properties across various studies, presenting graphs that compare data based on polymer type and hemp content. An extensive appendix categorizes studies by polymer type, processing method, and fiber treatment, providing a useful resource for further exploration in this field.