Characterization of the crystallographic properties of bamboo plants, natural and viscose fibers by X-ray diffraction method

Abstract

A comprehensive crystallographic investigation was performed by using X-ray (from cobalt source) diffraction (XRD) technique on different bamboo species, natural bamboo fibers (NBFs), commercial bamboo viscose products, and different conventional fibers. Crystallinity indexes (CIs) were estimated as 61–67% of bamboo plants, 69–73% of NBFs, 35–40% of bamboo viscose, and 77–80% of cotton fibers in this study. Results suggest that CI gradually increased during the delignification process to create NBFs up to a certain point and then decreased with further processes. Knowing this behavior informs decisions of the appropriate chemicals or enzymes for further modification processes and continuing to maintain the expected strength of the fiber. Therefore, delignifying raw bamboo increased the strength of the fibers until the maximum CI was achieved, but further extraction of lignin reduced the strength of the NBF resulting in a higher number of fiber breakage and short fibers. Red Margin was found to have lower CI that hinted at easier NBF extraction. With overall crystallite size of 35–39 Å, four crystalline peaks were detected in all bamboo and NBF specimens as (101), and at 17.0–18.6°, 18.5–19.4°, ∼25.5°, and ∼40.5°, respectively. Moreover, this study provides a list of lattice planes, interplanar spacings, reflection angles, and crystallite dimensions of the four targeted bamboo and NBF materials.