Acetylation fiber

Korai, H. (2001). Effects of low bondability of acetylated fibers on mechanical properties and dimensional stability of fiberboard. Journal of Wood Science, 47(6), 430-436. 

Rowell, R.M., Youngquist, J.A., Rowell, J.S. and Hyatt, J.A. (1991). Dimensional stability of aspen fiberboard made from acetylated fiber. Wood and Fiber Science, 23(4), 558-566. 

Table I shows the equilibrium moisture content (EMC) of several lignocellulosic materials at 65 percent relative humidity (RH). Reduction in EMC at 65 percent RH of acetylated fiber referenced to unacetylated fiber plotted as a function of the bonded acetyl content is a straight line (Fig. 2). Although the points shown in Figure 2 come from many different lignocellulosic materials, they...

Two very interesting observations that we recently made in the acetylation of many different types of agro-based fibers were that the rate of acetylation of many different types of agrofibers was essentially the same (Fig. 3) and that the relationship between the reductions in equilibrium moisture content (EMC) at 65% RH of these different types of acetylated fibers referenced to unacetylated fiber as a function of the bonded acetyl content results in a straight line plot (Fig. 4) [23]. 

These results show that the fibers of native rayon are not at all dispersed in a cellulose acetate matrix, but appear there as tangled bundles. On the other hand, acetylated fibers are able to disperse fiilly into tire cellulose acetate matrix, into... 

These partially acetylated fibers are aheady themselves a thermoplastic material they can be further assembled by means of an exogenous Unk. They are also able to form links directly by compression at a temperature close to the melting point of cellulose acetate (Fig. 54). 

Equilibrium Moisture Content (EMC) and Thickness Swelling (TS) of Fiberboards Made from Control and Acetylated Fiber... 

Rate and Extent of Thickness Swelling in Liquid Water of Kenaf Fiberboards Made from Control and Acetylated Fiber and a Phenolic Resin [Resin content of boards 8%]... 

The acetylation of hydroxyl groups reduces their hydrophilicity, causes bulking of the cell wall and renders the material less susceptible to biological decay. The acetylated fibers show lower ECM, less weight loss and reduced erosion rate compared with non-acetylated fibers. 

Weight loss measurement was one of several methods used to study the biodegradation of cellulose fibers from flax by two strains of Cellvibrio [59], These aerobic cultures initially contained 0.1 g of natural fiber or fibers with different degrees of acetylation. After 13 days of incubation, weight losses of 20% to 76% were recorded these data showed that more highly acetylated fibers were more resistant to biodegradation. 

Table 2.30 Performance of commercial polyvinyl acetyl fibers...

Zini et al. [50] prepared composites of a bacterial copolyester poly(3-hydroxybutyrate-co-3-hydroxyhexanoate], P(3HB-co-3HH), reinforced with flax fibers by compression molding. In order to improve fiber-matrix adhesion in composites, fibers chemically modified at the surface (by acetylation or by short-chain-PEG grafting] were also used. The best results were obtained with surface acetylated fibers. In the flax fiber composites the crystallization rate of P(3HB-co-3HH] remarkably increased compared with that of the plain polyester. The fibers displayed a nucleating effect on P(3HB-co-3HH] crystallization, whose magnitude depended on fiber surface chemistry. This feature was confirmed by the appearance of trans-crystallinity in isothermal crystallization experiments run in a hot stage of a polarized optical microscope. 

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