Surface modification of Alberta based hemp fibers

Abstract

Chemical treatments are conducted in this study to modify lignocellulosic composition and to improve the surface characteristics and mechanical properties of the decorticated and retted Alberta (AB)-based hemp fibers, which are investigated for the first time to meet the standards required for the composite material applications. A detailed approach was adopted where physical and chemical treatments were performed to produce uniform and clean fibers. This was conducted to make the fibers suitable for processing and to determine factors such as lignocellulosic biomass (cellulose, hemicellulose, and lignin), tensile properties (strength and modulus), chemical treatment effects on fiber dimension (single fiber diameter), and the cost of single chemical cleaning, which can be together considered when choosing an optimal chemical treatment. Hydrogen peroxide (H₂O₂) at concentrations of 4 %, 5 %, and 6 % vol/vol, and (3-Glycidyloxypropyl)trimethoxysilane (GPTMS) at 1 %, 5 %, and 20 % wt/wt treatments significantly altered the fiber composition and increased both cellulose and lignin content. GPTMS treatment at 1 % wt/wt, despite its effect on lignocellulosic content compared to H₂O₂, provided advantageous mechanical properties, balancing strength and consistent fiber performance with minimal variability. Notably, fibers treated with 1 % vol/vol GPTMS were diametrically smallest and showed the maximum increase of 65.08 % in tensile strength compared to untreated retted hemp fibers. From a cost standpoint, 1 % wt/wt GPTMS was the most economical at CAD $1.08 per gram of fiber, while the 6 % vol/vol H₂O₂ treatment was significantly more expensive for manufacturing scalability. In conclusion, our findings highlight the potential of 1 % vol/vol GPTMS treatments to enhance the properties of untreated hemp fibers, and make them a viable and sustainable option for chemical treatment to produce high-performance sustainable materials.