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Etude des mécanismes de gonflement et de dissolution des fibres de cellulose native

Abstract : Cellulose is a natural polymer, which belongs to polysaccharide family. Cellulose offers numerous product development opportunities but cellulose is difficult to process: it can not be melted. Thus cellulose must be either solubilised or derivetised. This is the main reason that pushed us to study and understand the swelling and dissolution mechanisms of native cellulose fibres (cotton, wood, sisal, abaca, hemp, flax and ramie). Data obtained with cotton and wood samples without outer layers, and cellulose derivatives allow us further information. The chemical agents, investigated as solvent or swollen agents, are aqueous (N-methylmorpholine N-oxide - water with various water content, or sodium hydroxide - water - additives) or ionic liquids. We identified five modes describing the behaviour of cellulose native fibres dipped in chemical agents: Mode 1: fast dissolution by disintegration into fragments Mode 2: large swelling by ballooning, and dissolution Mode 3: large swelling by ballooning, and no dissolution Mode 4: homogeneous swelling, and no dissolution Mode 5: no swelling, and no dissolution Despite the morphological differences between the different types of vegetal fibres or cellulose derivatives, they all follow the same modes of swelling and dissolving. We can distinguish different zones with one fibre during the ballooning. The three main components are the followings: the balloons, the membrane (surrounded the balloons with helicoidal feature) and the unswollen section. Each of these parts undergoes a typical swelling and dissolution behaviour. The components of the balloon membrane are the primary wall, plus part of the secondary wall. The membrane is the most difficult part to dissolve. Cellulose inside the balloons is not only swollen, but dissolved. The swelling and dissolution mechanisms of native cellulose fibres are not determined by the chemical nature of chemicals tested as solvent systems. Even if the quality of solvent plays a major role concerning the induced mechanisms, the key parameter is the morphological architecture of native cellulose fibres.
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Submitted on : Friday, July 13, 2007 - 8:00:00 AM
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  • HAL Id : pastel-00002729, version 1

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Céline Cuissinat. Etude des mécanismes de gonflement et de dissolution des fibres de cellulose native. Sciences de l'ingénieur [physics]. École Nationale Supérieure des Mines de Paris, 2006. Français. ⟨pastel-00002729⟩

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