Gradient in Dissolution Capacity of Successively Deposited Cell Wall Layers in Cotton Fibres

Abstract

Summary: The dissolution of cotton fibres has been studied at different development stages before and after the onset of secondary wall deposition in solvents of varying quality. We show that the dissolution of the primary wall is inefficient even in good solvents. In moderately good solvents, the inside of the secondary wall dissolves by fragmentation, whereas the outside of the secondary wall swells. These data demonstrate the existence of a centripetal radial gradient in the dissolution capacity within the fibre, which must be related to age-dependent structural variation in the cell wall layers.

Rotation and contraction of native and regenerated cellulose fibers upon swelling and dissolution: the role of morphological and stress unbalances

“…1c). As we demonstrated recently (Le Moigne et al 2008), the S1 wall then the primary wall will slowly dissolve later.…”

“…As was recently demonstrated, the secondary S2 wall is the easiest to dissolve as compared to the external walls which contain larger amount of noncellulosic components (Le Moigne et al 2008). The solvent thus goes inside the fiber through the primary wall which is permeable to the solvent but not easy to dissolve and not extensible (Fig.…”

“…1a). In moderate quality solvent, it was shown that the S2 wall dissolves by fragmentation (Le Moigne et al 2008) and as a consequence, the S1 wall swells transversely. Optical observations show that the primary wall breaks (Fig.…”

“…Similar mechanisms were also observed when using other solvents like NaOH-water with or without additives (Cuissinat and Navard 2006b), ionic liquids (Cuissinat et al 2008a) and other chemicals (Cuissinat 2006) for varied plant fibers (Cuissinat and Navard 2008) and for some cellulose derivatives that were prepared under heterogeneous conditions (Cuissinat et al 2008b). In a recent paper (Le Moigne et al 2008), the existence of a centripetal radial gradient in the dissolution capacity within cotton hairs was demonstrated. The sequence of dissolution was shown to be first the S2 wall, then the S1 wall and finally the primary wall meaning that the older was the cellulose deposition, the more difficult it is to dissolve it.…”

Swelling and dissolution mechanisms of regenerated Lyocell cellulose fibers

“…The present paper is aimed at increasing the knowledge of Lyocell morphology by performing detailed optical microscopy analysis of the swelling and dissolution of these fibers. The same approach that proved to be fruitful for native fibers Navard 2006, 2007;Le Moigne et al 2008, 2010a was used. The method consisted of swelling and dissolving Lyocell fibers in a mixture of NMMO-water with various contents of water (from monohydrate, i.e.…”