Cellulosates, alkali metal polymers

The resistance of polymers to corrosives is dependent on structure. Some polymers, such as cellulose acetate, do not have outstanding resistance to acids and alkalis. Mosf polymers are less brittle than the more chemically resistant ceramics and more resistant to corrosives than most metals. 

Emulsification is the most important act of the washing process. To prevent secondary soil deposition, formation of a coalescence-stable low-concentration emulsion is needed. As it is shown above (see section 6.4), the formation of such an emulsion is possible under real conditions considering the surfactant concentration in the washing solution and hydrodynamic conditions of the soil deposition process. As far as solid soils are concerned, the process of dispersion of particles is important here. To prevent their re-deposition on the surface washed, water-soluble polymers are used, e.g. carboxymethyl cellulose. Effective dispersion agents are also inorganic salts, e.g. alkali metal silicates. 

The fundamental theory of phase transfer catalysis (PTC) has been reviewed extensively. Rather than attempt to find a mutual solvent for all of the reactive species, an appropriate catalyst is identified which modifies the solubility characteristics of one of the reactive species relative to the phase in which it is poorly solubilized. The literature on the use of PTC in the preparation of nitriles, halides, ether, and dihalocarbenes is extensive. Although PTC in the synthesis of C- and 0-alkylated organic compounds has been studied, the use of PTC in polymer synthesis or polymer modification is not as well studied. A general review of PTC in polymer synthesis was published by Mathias. FrecheE described the use of PTC in the modification of halogenated polymers such as poly(vinyl bromide), and Nishikubo and co-workers disclosed the reaction of poly(chloromethylstyrene) with nucleophiles under PTC conditions. Liotta and co-workers reported the 0-alkylation of bituminous coal with either 1-bromoheptane or 1-bromooctadecane. Poor 0-alkylation efficiencies were reported with alkali metal hydroxides but excellent reactivity and efficiencies were found with the use of quaternary ammonium hydroxides, especially tetrabutyl- and tetrahexylammonium hydroxides. These results are indeed noteworthy because coal is a mineral and is not thought of as a reactive and swellable polymer. Clearly if coal can be efficiently 0-alkylated under PTC conditions, then efficient 0-alkylation of cellulose ethers should also be possible. 

The membrane was prepared by blending the present polymer, 5, and cellulose acetate (CA) (VCA=3/7 by wt.). The membrane showed the capability of active and selective transport of alkali metal ions at moderately low concentrations. 

The first attempts to produce a graft copolymer of poly(amino acids) onto the natural polymers, such as cellulose, starch, and their derivatives, were carried out by Zilka and Avny in 1965. Sodium methoxide was known to be an initiator of NCA polymerization. Therefore, they proposed to use alkoxide derivatives of polysaccharides as macroinitiators for the graft copolymerization of NCA s of a-amino acids. All known methods for production of alkoxide derivatives of natural polymers, such as the reaction of polyhydroxy polymers with sodium metal in liquid ammonia, or exchange reactions between lower alkoxides and polyhydroxy polymers, - were unsatisfactory for the subsequent graft copolymerization of NCAs, because any residual base would lead to homopolymerization. In addition, alkoxide derivatives of cellulose acetate and nitrocellulose could not be obtained by these conventional methods due to chemical degradation. Zilka et al., finally found that the reaction of alkali metal naphthalenes [20] with polyhydroxy polymers in either... 

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