A Review of Cellulosic Fibre Surface Modification Techniques - The Case of Ramie

Abstract

The demand for cellulosic fibres as a reinforcement in polymers is growing due to their renewable, biodegradable, and ecologically favourable properties. In addition, they are lower in density than e.g. glass fibres, which will help in making lightweight composites. Besides, there is no health hazard with ease of processing and minimum damage to the processing equipment. Despite their advantages and high demand, their utilization in industrial applications is still limited. This is due to their inherent polar and hydrophilic nature and their consequent incompatibility with hydrophobic polymers. Therefore, it is often necessary to do hydrophobic modification treatment. The review examines a range of strategies for modifying ramie surfaces, encompassing physical, chemical, and biological processes. It also analyzes the procedures and techniques involved in the preparation and manufacturing of ramie-reinforced polymeric biocomposites. Moreover, an investigation is conducted to evaluate the performance of the composites produced. The performance evaluation includes both before and following fibre treatment, covering surface morphology, wettability, chemical composition, mechanical properties, and flame retardancy. Most of the researchers reported that alkaline and silane coupling agent treatments are the most prevalently applied pretreatments. Compared to biological and physical methods, the application of chemical agents enables excellent adhesion of fibre to polymer resins. However, the utilization of solvents such as ethanol and methanol increases the amount of waste produced and toxic compounds released.