Removing pectin and lignin during chemical processing of hemp for textile applications

Pectin and lignin are both very important noncellulosic substances occurring in hemp fibers. The main task in preparing hemp fibers for textile applications is to remove these noncellulosic substances without damage to the fiber cellulose. Pectin and lignin in hemp before and after chemical processing are characterized by infrared spectroscopy. The influence of chemical processes, fiber regions, and alkaline boiling parameters on lignin and pectin removal are investigated in this paper. The results indicate that the alkaline boiling process is effective for removing pectin and lignin. There is no residual pectin in the fibers after the alkaline treatment, but there is a residual level of lignin. The concentration levels of both sodium hydroxide and sodium sulphite have significant effects on lignin removal, and there are variations in lignin properties and accessibility from the lower to the upper regions of the hemp stem.