Surface-Active Polymers from Cellulose

Water-soluble cellulose ethers (cellulose derivatives, or CDs) have found many applications. The major Application areas for CDs are [1-3]  

Surfactants from Renewable Resources Edited by Mikael Kjellin and IngegSrd Johansson 2010 John Wiley Sons, Ltd 

In 2007 the total worldwide capacity for nonionic CDs was 363000 tonnes per year. 

All the common reagents for the etherification reaction of cellulose are either epoxides or halides. Ethylene oxide (EO), propylene oxide (PO) and alkyl glycidyl ethers are examples of epoxides and monochloroacetic acid (MCA), methyl chloride (MC), ethyl chloride (EC) and long-chain alkyl bromides are examples of halides that are commonly used. The reactions are performed at elevated temperature. Reactions of volatile compounds such as EO, PO, MC and EC require a pressurized reaction vessel. 

Each AHG has three hydroxyl groups available for reaction. The reaction of one EO or PO molecule to one of the hydroxyl groups on an AHG results in a new hydroxyl group 

---

The classic studies of Saunders( 17) demonstrated that in the presence of excess surfactant methyl cellulose (MC) would desorb from monodispersed polystyrene latices. MC is one of the most surface active water-soluble polymers (W-SPs) and it will readily dominate the surface pressure 7T (7T = cre - cr t where cr is the surface tension of water and is the surface tension of the aqueous polymer solution) of the aqueous solution. For example, hydroxyethyl cellulose (HEC) lowers the surface tension of water much less than MC or HPMC, and when the combination of HEC and MC or HPMC in water is studied, there is no notable influence of HEC on the surface pressure (Figure 2). 

The cellulose types of chiral stationary phase currently available are coated on a wide pore silica support as opposed to being bonded to the silica surface. They take two basic forms, those derived from cellulose polymers and those derived from amylose polymers they are reported to have molecular weights of up to 40,000 Daltons. The basic difference between the two polymers is that the cellulose adopts a linear structure, whereas the amylose forms a helical structure. Both cellulose adn amylose unit contains 5 chiral centers. As a result the polymers contain a large number of chirally active sites and thus a relatively high probability of chird site interaction with the solute. The structure of the cellulose type of stationary takes the following form. 

This is the final category considered when the polymer is itself markedly surface active, the situation becomes very different in many cases the polymer alone will be able to sustain a foam generated from its aqueous solution. An example (61) of this is the hydro-phobically substituted cationic cellulose polymer Quatrisoft LM 200. Many other examples can be found in the literature, including proteins themselves and their derivatives. On addition of a surfactant, mixed adsorbed films will form and the film and foaming characteristics will depend very much on the specifics of the components themselves, the nature of their interaction, and their relative concentration. (See Fig. 11.)... 

Proteins, natural polymers, polysaccharides, and surgars from foodstuffs and animal or plant secretions (albumin, starch, blood, sugars, resins, etc.). The polymeric, cross-linkable nature of these soils and their possible reactivity (with cellulose, for instance) makes them difficult to eliminate, for they can adhere strongly to porous textile surfaces and polymerize there. They can be removed by depolymerization with specific enzymes, together with the action of the other ingredients of the formulations (alkaline substances, surface-active agents). 

Figure 7 Schematic model of self-assembling process of synthetic cellulose on the surface of enzyme associations diffusion of monomers to active sites of the enzyme aggregate (a), which synthesizes cellulose molecules (b) and self-assembles them In situ Into dendritic cellulose aggregates with Dm = 2.1 and Ds = 2.3 in the reaction medium around the enzyme aggregates (c) The cellulose aggregates eventually growing into the dome (d). The cellulose aggregate surrounding the enzyme association has enough free space for diffusion of monomers from the reaction medium into the active sites and for diffusion of terminated polymers from the active sites Into the reaction medium as shown in part (e) and discussed in Section 2.13.3.2. From Tanaka, H. Koizumi, S. Hashimoto, T. et al. Macromolecules 2007, 40, 6304-6315. ...

---