Composite polyamide membrane having preferred azo content

Patent metadata

Field	Value
Publication number	US-9555378-B2
Application number	US-201415102879-A
Country	US
Kind code	B2
Filing date	Dec 15, 2014
Priority date	Jan 9, 2014
Publication date	Jan 31, 2017
Grant date	Jan 31, 2017

Abstract

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

First claim

The invention claimed is:

1. A thin film composite polyamide membrane comprising a porous support and a thin film polyamide layer characterized by possessing an azo (—N═N—) content of from 0.75% to 0.95%, as measured by pyrolysis gas chromatography using ammonium dichromate as a calibration standard and pyrolizing the polyamide layer at 550° C. for 6 seconds; wherein the azo content refers to the amount of diazonium and azo coupling resulting from two aromatic compounds coupled by an azo (—N═N—) group, and wherein the thin film polyamide layer is further characterized by producing a ratio of dimers represented by Formula II and III from 2.0% to 4.0% upon pyrolysis at 650° C. as measured by GS MS.

2. The membrane of claim 1 wherein the thin film polyamide layer is further characterized by possessing an azo content of from 0.80% to 0.90%.

3. The membrane of claim 1 wherein the thin film polyamide layer is further characterized by producing a ratio the dimers of from 2.4% to 4.0%.

4. The membrane of claim 1 wherein the thin film polyamide layer is further characterized by producing a ratio the dimers of from 3.0% to 4.0%.

5. The membrane of claim 1 wherein the thin film polyamide layer is further characterized by possessing a dissociated carboxylate content of less than 0.18 mol/kg as measured by RBS at pH 9.5.

6. The membrane of claim 1 wherein the thin film polyamide layer is further characterized by possessing a dissociated carboxylate content of less than 0.09 mol/kg as measured by RBS at pH 9.5.

7. The membrane of claim 1 wherein the thin film polyamide layer is further characterized by possessing a COOH/amide ratio of equal to or less than 0.10, as measured by ATR IR.

8. The membrane of claim 1 wherein the thin film polyamide layer is further characterized by possessing a COOH/amide ratio of equal to or less than 0.13, as measured by ATR IR.

9. The membrane of claim 1 wherein the thin film polyamide layer is further characterized by possessing: i) a dimer ratio of from 2.0% to 4.0%, ii) a dissociated carboxylate content of less than 0.09 mol/kg, and iii) a COOH/amide ratio of equal to or less than 0.10.

Assignees

• Dow Global Technologies Llc

Inventors

• Roy Abhishek
• Cieslinski Robert C
• Gerhart Bruce B
• Hawn David D
• Paul Mou
• Qiu Xiaohua
• Rickard Mark A
• Rosenberg Steven
• Tomlinson Ian A
• Zu Chengli

Classifications

• B01D2323/36

  Introduction of specific chemical groups · CPC title

• B01D71/56 Primary

  Polyamides, e.g. polyester-amides · CPC title

• B01D67/0006

  by chemical reactions (in-situ polymerisation, polycondensation, cross-linking or reaction for manufacturing composite membranes B01D69/125) · CPC title

• B01D2323/40

  in-situ membrane formation · CPC title

• B01D69/125 Primary

  In situ manufacturing by polymerisation, polycondensation, cross-linking or chemical reaction · CPC title