Monday 12 November 2012

Practical Polysaccharides (Part 4) Cellulose fibres to store functional agents

Part 4 of the paper by Jacek K. Dutkiewicz of Buckeye Technologies Inc given at this years Insight Conference organised by MTS in Norfolk Virginia. (Click here for Part 1)
The coarseness and length of natural wood or cotton-linter cellulosic fibers may vary depending on the origin, geography and age of the plant.  There are tools known by cellulose pulp experts to control or modify fiber geometry but only to a limited extent since the basic parameters have been already defined by Mother Nature.   Cellulosic fiber webs possess excellent absorbent properties, in large part because of their high surface energy.  Water-based liquids, depending on their liquid rate constant W [4], can move more quickly within the pores of cellulose fiber networks than in other kinds of porous materials.  The liquid rate constant is defined here as a ratio of surface tension to viscosity of a given liquid.   The units of W are the same as the physical units of velocity.   This parameter can be used in mathematical descriptions of the rate of fluid flow for instance in the Laplace and Lucas-Washburn equations (Fig.6).

Cellulosic fibers have unique properties such as surface polarity and reactive
sites (plurality of hydroxyl and some amount of carboxyl groups) which enable them to serve as ideal carriers of useful functional components which can be chemically attached to the polymer functional groups or be physically bound within the fiber micropores (Fig. 7).   Depending on the need these functional agents can be permanently immobilized on the cellulose matrix or be released to the medium during the use of the system.

(Go to Part 5)

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