摘要:
Novel polymers having high activity as cationic surface-active agents are prepared by the addition polymerization of ethylenically unsaturated aromatic sulfonium salts, e.g., ##STR1## When such polymers are heated and/or dried, they are irreversibly converted to inert, nonionic residues without the elimination of odorous by-products.The novel sulfonium salt polymers having relatively low molecular weight and low charge density are particularly useful as surfactants or emulsifiers in the emulsion polymerization of ethylenically unsaturated monomers such as styrene, butadiene, alkyl acrylates and the like. The polymers having high molecular weight and high charge density are useful as thickeners and flocculants.
摘要:
Coatings having very low critical surface tensions comprise (1) a hydrophilic polymer such as polyacrylamide, (2) an ionic perfluorocarbon compound such as 3-[((heptadecafluorooctyl)sulfonyl)amino]-N,N,N-trimethyl-1-propanaminium iodide and (3) a cyclic sulfonium zwitterion cross-linking agent such as 2,2-bis(3-tetrahydrothiophenium-4-oxidophenyl)-propylidene. Such coatings are most advantageously employed as release coatings on internal surfaces of chemical reaction vessels in order to minimize the deposition (build-up) of undesirable materials on such internal surfaces.
摘要:
Novel cyclic sulfonium ylids corresponding to the formula ##STR1## wherein R is a hydrocarbylene radical (or a hydrocarbylene radical whose chain length is interrupted by an atom of oxygen or sulfur) of from 2 to about 20 carbon atoms, are useful as cross-linking agents for carboxyl-containing polymers. The compounds are conveniently prepared by reacting phenacyltetrahydrothiophenium bromide with the corresponding hydrocarbylene diisocyanate in the presence of a strong base (e.g. sodium hydride) and anhydrous tetrahydrofuran.
摘要:
A water-based polymer composition containing a polyvalent metal complex and a polymer having pendant strong cationic groups and weak acid salt groups forms fast dry-to-the-touch coatings that are resistant to water and many organic solvents. These coatings can be removed with ammonia-containing solvents.
摘要:
Novel reverse osmosis membranes and a method for preparing such membranes are described. A substrate can be coated with a first compound bearing a plurality of onium groups and a second compound bearing a plurality of nucleophilic groups. The resulting coating cures readily upon exposure to actinic radiation.
摘要:
The invention is a semi-permeable gas separation membrane containing a non-ionic surfactant and which possesses improved resistance to thermal compaction or aging. The invention includes a process for making such membranes as well as a method of using such membranes.
摘要:
Cationic organic impurities such as ternary sulfonium ions and quaternary ammonium and phosphonium compounds are effectively removed from polar liquids such as water or water/alcohol mixtures by contacting the polar liquid with an absorbent comprising a trinitroarenol such as a picric acid. This method is particularly effective for removing such cationic impurities from polar liquids containing organic zwitterions.
摘要:
A novel composite membrane and methods of making the membrane are described. The discriminating layer of the membrane is prepared by reaction of a reactive cationic compound group with a compound bearing a nucleophilic moiety. At least one of the reactants bears an average of two or more reactive groups. The reaction product contains covalent bonds formed via charge eliminating reactions.In a preferred embodiment of the invention, the nucleophilic group is anionic and a coacervate is formed initially on a microporous substrate. The resulting membrane may be useful for reverse osmosis, gas or ultrafiltration separations.
摘要:
An improved reverse osmosis membrane and process for making the same is described. The membrane is prepared by treating a polymer bearing primary amine groups with nitrous acid or a diazonium compound so as to react the resulting diazonium groups with other groups present. The resulting membrane possesses improved chlorine resistance. When the nitrous acid treatment is employed, the water flux of a polyamide membrane is frequently increased with little or no effect on the salt rejection of the membrane.
摘要:
Polymers comprising pendant rearranged oxazoline and/or oxazine portions linked to a perfluorocarbon moiety having a perfluoroalkyl group are prepared. Such polymers can provide coating compositions which exhibit critical surface tensions of wetting of less than about 15 dynes/cm.