Influence of alkali treatment on the fine structure and morphology of bamboo fibers

Bamboo fibers in the form of strips and dust were treated with NaOH solution of varying concentration (10, 15, and 20%). These treated and untreated samples were then subjected to FTIR and morphological studies. Again XRD study was carried out on those treated and untreated bamboo samples in both strip and dust form. It was found that during alkali treatment a lattice transformation from cellulose-I to cellulose-II took place. It is observed from IR index value that the conversion is maximum in between 15 and 20% of alkali treatment. Swelling in NaOH introduces considerable changes in crystallinity, orientation angle, etc. Degree of crystallinity and crystallinity index for bamboo strips increases with increasing treatment concentration of alkali and falls off after 15% alkali concentration. This is also supported by d-spacing value. Orientation factor f(x) was calculated from the FWHM and it was found that f(x), value has been increased from 0.9879 to 0.9915 for 15% alkali treated and again lowered to 0.8522 for 50% alkali treated samples. Same observation of X-ray study was obtained for dust samples but at an earlier concentration. Morphological study of bamboo dust with scanning electron microscope indicates fibrillation at higher alkali concentration. (c) 2006 Wiley Periodicals, Inc.