Recent advances in polymer composites reinforced with nettle and bamboo fibers: fabrication, properties, and applications

Growing demands for environmentally friendly, lightweight, and sustainable products has stimulated interest in the study of natural fiber-reinforced polymer (NFRP) composites. Lignocellulose reinforcement is an area where researchers are studying new alternatives to traditional reinforcements like wood and cotton with emphasis on the use of bamboo and nettle fibers, because of their higher specific strengths, fast-growing renewable resources, and lower ecological impacts. Bamboo and nettle fiber-polymer composite research was reviewed with a focus on raw material properties, polymer matrix properties, surface modification methods, hybrid reinforcement properties, processing methods, and performance trends of these materials. Reports from the literature suggest that bamboo and nettle fibers have mechanical properties similar to other well-established bast fibers (flax and hemp), and both can improve tensile, flexural, and impact properties when incorporated into thermosets or thermoplastics. Interfacial properties were determined to be the major factor influencing composite property performance, and application of treatments to modify interfacial properties (alkaline treatment, silane coupling agent, bio-based coatings, and nanoparticle-based coatings) enhanced fiber-matrix compatibility, stress-transfer efficiency and improved thermal stability. Hybridized reinforcement (bamboo-nettle and synthetic-natural) methods were found to take advantage of synergy between different fibers to enhance damage resistance and reduce moisture absorption.