Thermal modification cellulose

Modification of cotton textiles by chemical plating of their surfaces with cobalt (II) or nickel (II) salts produced metallized fibers and fabrics with high electrical conductivity and the capability to transport and dissipate thermal energy (109). The heat capacity of cellulose acetate fibers was increased by treatment with epoxy compounds (110). 

The other approach is to modify the cellulose chemically. Rowell et al. (1994) discussed the application of both thermal and chemical modification techniques to modify fibre used to manufacture low density fibreboards. The acetylation technique appears to offer significant improvement in the stability of panels, but the technique has not achieved significant commercial success largely because of the cost of the chemicals required. 

Post-formation chemical, thermal and physical treatments are often used to modify the performance characteristics of membranes. Flnken ( ) presents recent results from his studies on thermal and physical modifications of Integrally-skinned cellulosic blend... 

The modification of cellulose with alkaline carbon disulfide to introduce xanthate groups has been extensively exploited in the industrial production of viscose. Early work on the preparation and properties of starch xanthate has been discussed. Xanthate derivatives of cellulose and starch have been discussed with respect to general xanthate chemistry, and the xanthation of cellulose in homogeneous medium is known to be a second-order reaction. Cellulose xanthate shows some potential as a matrix for enzyme insolubilization, " and stable derivatives of this xanthate may be prepared by transesterification. Thermal decomposition of cellulose allyl- and benzyl-xanthates gives 5,6-cellulosene. Some thiocarbonyl derivatives of polysaccharides have been prepared. "... 

Polysaccharides and their graft copolymers find extensive applications in diversified fields. Grafting is known to improve the characteristic properties of backbones. Such properties include water repellancy, thermal stability, flame resistance, dyeability and resistance towards acid-base attack and abrasion. Modification of natural cellulosics through graft copolymerization of methyl methacrylate onto Cannabis indica, rayon, jute, cotton, etc., has resulted in the improvement of their morphology and other physicochemical properties [9-23]. 

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. 

Studies on Ugnocellulosic material modification were also cmiducted by Nekkaa et al. [18]. The cellulose fibers obtained from Spanish broom (Spartium junceum) were subjected to silane s action to improve adhesion between composite components. Thermal analysis confirmed the nucleating effect uprm the addition of unmodified fibers, while the addition of modified fibers did not significantly influence the crystallinity of polypropylene matrix. 

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