Dow Global Technolgoies LLC

The Dow Chemical Company

David D Hawn

Abhishek Roy

Mou Paul

Steven Rosenberg

Robert C Cieslinski

Ian A Tomlinson

XiaoHua Qiu

Chengli Zu

Steven Douglas Jons

Tina L Arrowood

Mark Alan Rickard

Bruce B Gerhart

Martin H Peery

Robert E Reim

Huang Wu

Derek M Stevens

Anand S Badami

Xiao-Hua Qiu

Mark A Rickard

A thin film composite polyamide membrane comprising a porous support and a thin film polyamide layer characterized by possessing: i) an azo (&#x2014;N&#x2550;N&#x2014;) content of from 0.40% to 1.00%, as measured by pyrolysis gas chromatography; and ii) a dissociated carboxylate content of at least 0.40 mol/kg as measured by RBS at pH 9.5.

Composite polyamide membrane having azo content and high acid content

A method for making a composite polyamide membrane comprising a porous support and a thin film polyamide layer, wherein the method includes the step of applying a polyfunctional amine monomer and polyfunctional acyl halide monomer to a surface of the porous support and interfacially polymerizing the monomers to form a thin film polyamide layer, wherein the step of applying the polyfunctional acyl halide monomer to the porous support includes the step of combining the polyfunctional acyl halide monomer with a non-polar solvent at a concentration of at least 0.18 weight percent to form a coating solution which is applied to the surface of the porous support, and wherein the interfacial polymerization is conducted in the presence of a tri-hydrocarbyl phosphate compound which is provided in a molar ratio of at least 0.5:1 with the polyfunctional acyl halide monomer. Many additional embodiments are described including membranes made from the subject method and applications for such membranes.

Composite polyamide membrane

A thin film composite polyamide membrane having a porous support and a thin film polyamide layer comprising a reaction product of m-phenylene diamine (mPD) and trimesoyl chloride (TMC), characterized by the thin film polyamide layer having a critical strain value of less than 10%. In another embodiment, the thin film polyamide layer has a modulus of greater than 0.75 (GPa). In yet another embodiment, the thin film polyamide layer has an equilibrium swelling value of at least 45%. In another embodiment, the thin film polyamide layer has a thickness of at least 230 nm.

Composite polyamide membrane with improved structure

A thin film composite polyamide membrane comprising a porous support and a thin film polyamide layer characterized by possessing: i) an azo (&#x2014;N&#x2550;N&#x2014;) content of from 0.30% to 0.80%, as measured by pyrolysis gas chromatography; and ii) a dissociated carboxylate content of at least 0.18 mol/kg as measured by RBS at pH 9.5.

Composite polyamide membrane having high acid content and low azo content

A thin film composite membrane including a porous support and a thin film polyamide layer characterized by having a dissociated carboxylate content of at least 0.45 moles/kg at pH 9.5 and a method for making a composite polyamide applying a polar solution comprising a polyfunctional amine monomer and a non-polar solution comprising a polyfunctional amine-reactive monomer to a surface of the porous support and interfacially polymerizing the monomers to form a thin film polyamide layer, wherein the method is characterized by the non-polar solution comprising at least 0.025 wt % of an acid compound including at least one carboxylic acid moiety and at least one amine-reactive moiety selected from acyl halide and anhydride.

Composite polyamide membrane with increased carboxylic acid functionality

A thin film composite polyamide membrane comprising a porous support and a thin film polyamide layer characterized by possessing an azo (&#x2014;N&#x2550;N&#x2014;) content of from 0.75% to 0.95%, as measured by pyrolysis gas chromatography.

Composite polyamide membrane having preferred azo content

Method for determining total organic sulfur using reductive pyrolysis and specific electrochemical detection of sulfide ion at a mercury electrode. The method is especially useful for the determination of sulfur in matrices containing halogen or nitrogen compounds. Under routine conditions, a detection limit of less than 50 parts per billion (ppb) can be achieved using differential pulse cathodic stripping voltammetry as the detection mode.

Reductive pyrolysis method for determining trace sulfur

Growing community of inventors

Midland, MI, United States of America

David D Hawn