Enhancing hemp fiber performance: insights into chitosan treatment and structural evolution

Hemp fiber, recognized for its eco-friendliness, wide availability, and biodegradability, stands as a renewable resource with promising applications. To fully harness its potential, it is crucial to study the relationship between chitosan concentration and both the mechanical and thermal properties of hemp fiber. Understanding these effects can provide a direction to improve the properties and functionalities of hemp fiber, which are essential for many applications, including textiles and construction and automotive materials. Chitosan is known to enhance the antimicrobial and adsorption properties of fibers by changing the chemical properties of the fiber surface. However, up to now, a very limited number of studies have focused on the exact effect of chitosan on the mechanical and thermal stability properties of hemp fibers. Here, the effect of treatment with different concentrations of chitosan solutions is investigated to enhance the properties of hemp fibers and the treated hemp fibers are characterized. It is found that chitosan solution treatment can effectively improve the various properties of hemp fibers. The chitosan treatment improved the surface roughness of hemp fibers. The tensile strength and flexibility of hemp fibers were enhanced. The CSHF-1.5% sample exhibited the highest tensile strength of 616.11 MPa and the lowest tensile modulus of 15.61 GPa. The fiber swelling rate increased to 24.73% at a chitosan solution concentration of 1.5%. The results of thermogravimetric analysis and differential scanning calorimetry analysis demonstrated the effectiveness of chitosan solution treatment in enhancing the thermal stability of hemp fibers. These findings propose a promising method for a significant modification of hemp fiber's mechanical and thermal stability.