Effect of Growth Period and Sampling Section on the Chemical Composition and Microstructure of Raw Hemp Fibers

Abstract

Hemp fiber’s origin has a large impact on the physical properties of degummed fibers. In this research, the effect of hemp fiber origin on the treated fibers was studied mainly by evaluation of chemical composition and microstructure, as well as by the evaluation of the degummed fiber’s properties under a biochemical process. The samples were chosen from the stem with two different growth periods (an early and a late harvest time) and three different sections along the hemp stem (top, middle, and bottom). The results showed a vast variety of chemical compositions and microstructures for raw hemp fibers in different growth periods. The results of the chemical composition analysis indicated that the cellulose content in raw fibers ranged from 41.9±2.3% to 44.8±0.8% and that the lignin content ranged between 12.0±1.5% and 16.5±0.9%. Both the Fourier transform infrared (FT-IR) and X-ray diffraction (XRD) results demonstrated the close relation of the raw fiber’s character to the growth period and sampling section. The physical properties of degummed fibers with different origins were also tested, and large variations in length and linear density were found, which ranged from 42 mm to 67 mm for length and from 11.36±0.37 dtex to 21.55±0.54 dtex for linear density.