Kenaf fiber crystallinity

Stout has written a detailed review on jute and kenaf. X-ray diffraction patterns show the basic cellulose crystal structure, although in jute and kenaf the crystalline orientation is high and the degree of lateral order is lower than in flax. Batra" in a comprehensive review has highlighted the morphological structures and physical, mechanical and chemical properties of other long vegetable fibers. 

The effect of chemical modification of cellulose nanofibers on the properties of PLA nanocomposites has been investigated (44). Ac-etylated nanofibers, with a degree of substitution 1.07, were isolated from acetylated kenaf fibers by a mechanical procedure. The acet-ylated nanofibers were found to be more hydrophobic. Both crystallinity and thermal stability of acetylated nanofibers were lower in comparison to the non-acetylated nanofibers. 

The aim of this study was extraction of cellulose from kenaf fiber which is available in Malaysia and preparation of nanocellulose whiskers from extracted cellulose in controlled hydrolysis condition. Chemical composition, size of particles, morphology, crystallinity, and thermal analysis of cellulose whiskers were investigated. 

The X-ray diffraction (XRD) measurements were performed on a Bmker AXS-D8 Advance model system. The diffracted intensity of Cn Ka radiation (0.154 nm, 40 kV and 40 mA) was measured in a 20 range between 10° and 70°. Ground kenaf fibers and hydrolyzed cellulose sample were subjected to crystallinity analysis. 

The x-ray diffractograms showed the presence of cellulose I structure in all raw fibers. In the treated banana fiber, cellulose II structure was dominant. While cellulose I ([002] peak) is found in all five raw fibers, the [002] peak cellulose II is found as a shoulder in kenaf and ramie. The measured crystallinity (x%) in raw and alkali-treated fibers are shown in the table below ... 

Kargarzadeh H, Ahmad I, Abdullah I, Dufrensne A, Zainudin SY, Sheltami RM. Effects of hydrolysis conditions on the morphology, crystallinity and thermal stability of cellulose nanocrystals extracted from kenaf bast fibers. Cellulose 2012 19 855-866. 

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