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You are here: Home > Technique > Processes > Scientific report of the LGP2 > Paper physics > Contribution to the comprehension of fibres-chemical additives interaction with Environmental Scanning Microscopy           Update: February 26th 2007
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Researchers of the LGP2 (EFPG, INPG, CNRS, CTP)
(November 2006)
 
Documents taken from the
"Scientific Report of the Laboratory of Pulp and Paper Science and Graphic Arts - UMR 5518
Grenoble - France
January 2002-November 2005"

III - Paper physics

III - 3 - Contribution to the comprehension of fibres-chemical additives interaction with Environmental Scanning Microscopy

Raphäel Passas, Gérard Mortha

EFPG has just acquired an environmental scanning electronic microscopy (QUANTA 200 – FEI) equipped by a Peltier plate, a micro-injector, a micro-manipulator and a X-microanalysis system (SAHARA SDD probe and SPIRIT – PGT analysis system). This new material is a powerful tool to visualise the water influence on the fibre mat, their behaviour during drying and the influence of chemical additives on their surface.

The following example shows the action of a potassium permanganate (0.02 M) and sulphuric acid (0.02 M) solutions blend on the unbleached softwood fibres. This experience aims at realising an in-situ bleaching.

[Figure 1] shows the cellulose fibres in hydrated environment. One drop of the reaction mixture was deposited onto the fibre surface with the micro-injector device. A liquid film sleeve seems to be formed around the fibre. We assume that this is due to dissolution of cellulose macromolecules at the surface when submitted to the acid action. The dehydration complementary step realised with a pressure decrease [Figure 2] allows the visualisation of the fibre width reduction. The X-ray microanalysis allows highlighting the sulphur and potassium elements that are stemmed from sulphuric acid and potassium permanganate respectively. On the opposite, the manganese peak is absent. This finding needs some further investigations.

Dehydrated fibre before additive deposition   Fibre after treatment and after drying
Figure 1 - Dehydrated fibre before additive deposition   Figure 2 - Fibre after treatment and after drying
 
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