Water-soluble polymer hydroxypropyl methylcellulose

Early soil-release agents, applied particularly to resin-finished cellulosic goods, were water-soluble polymers, many being related to thickeners (section 10.8) such as starch, hydroxypropyl starch, sodium carboxymethylcellulose, methylcellulose, hydroxyethyl-cellulose, alginates, poly(vinyl alcohol) and poly(vinylpyrrolidone). These functioned essentially as temporary barriers and preferential reservoirs for soil, which was thus easily removed along with the finish in subsequent washing, when they then helped to minimise... 

Generally, the barrier or rate-controlling films are more permeable to water than the carrier films. The materials used for this purpose consisted of a base, film forming water-soluble polymer in combination with at least one hydrophilic component such as hydroxypropyl methylcellulose or polyvinylpyrrolidone. The polymers used were the same as those for the carrier films. Some recent developments are discussed herein. 

Water-soluble hydroxypropylmethyl cellulose and water-insoluble cellulose acetate are further treated with phthalic anhydride or succinic anhydride to yield hydroxypropyl methylcellulose phthalate, cellulose acetate phthalate, and hydroxypropyl-methylcellulose acetate succinate. These polymers are used as enteric materials and are water soluble or insoluble above or below a specific pH, respectively. 

Methods of Preparation of Hydrophobically Modified WSPs (HMWSPs). Incorporation of Hydrophobes into WSPs. Water-soluble cellulose derivatives ((hydroxyethyl)cellulose, (hydroxypropyl)cellulose, methylcellulose, etc.) or synthetic polymers containing hydroxyl groups (e.g., poly(vinyl alcohol)) can be reacted with a long-chain alkyl halide (2), acyl halide (2), acid anhydride (6), isocyanate (2), or epoxide (2, 3) under appropriate conditions to form an HMWSP. These reactions are shown in Scheme I. These postmodifications can be done in solution or in hetero-... 

As with the alkylated polysaccharides, the physicochemical properties of hydroxyalkylated polysaccharides have continued to be investigated, particularly those of commercial value. The general characteristics of 0-(2-hydroxyethyl)cellulose have been described, together with pro-cedmes for the viscosimetric measurement of solutions of the polymer, and the macromolecular properties of the polymer in solution, described earlier, have been reviewed. The effect of increasing the substitution of both water-soluble 0-(2-hydroxyethyl)- and 0-(2-hydroxypropyl)-cellulose is to decrease their afiBnities for water. Water-soluble 0-(2-hy-droxypropyl) cellulose can be fractionated in a way analogous to that for O-methylcellulose by utilizing solvent—nonsolvent mixtures. For polysac-... 

A simple foam generation apparatus is used to incorporate air into a conventional water-soluble polymeric excipients binder such as METHOCEL hypromeUose (hydroxypropyl methylcellulose). The resulting foam has a consistency like shaving cream. HypromeUose polymers are ideal candidates for this technology because they are excellent film formers and create exceptionally stable foams. 

Hydroxypropyl methylcellulose acetate succinate (HPMCAS), a cellulose ether ester derived from HPMC esterifled with acetate and succinate groups, is an enteric polymer soluble only in water of high pH or in polar organic solvents like acetone or tetrahydrofuran (THE). The enteric performance is due to the presence of carboxylic groups. At low pH, HPMCAS exists in its protonated... 

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