Composite polyamide membrane having high acid content and low azo content

Patent metadata

Field	Value
Publication number	US-9616392-B2
Application number	US-201415033936-A
Country	US
Kind code	B2
Filing date	Dec 15, 2014
Priority date	Jan 9, 2014
Publication date	Apr 11, 2017
Grant date	Apr 11, 2017

Abstract

A thin film composite polyamide membrane comprising a porous support and a thin film polyamide layer characterized by possessing: i) an azo (—N═N—) 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.

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:
i) an azo (—N═N—) content of from 0.30% to 0.80 wt %, as measured by pyrolysis gas chromatography using ammonium dichromate as a calibration standard and pyrolizing the polyamide layer at 550° C. for 6 seconds;
ii) a dissociated carboxylate content of at least 0.20 mol/kg of polyamide as measured by RBS at pH 9.5; and
iii) an amino phenol/m-phenylene diamine ratio of at least 0.15.

2. The membrane of claim 1 wherein the thin film polyamide layer is further characterized by possessing an azo content of from 0.40% to 0.75 wt %.

3. The membrane of claim 1 wherein the thin film polyamide layer is further characterized by possessing a COOH/amide ratio of equal to or greater than 0.14, as measured by ATR IR.

4. The membrane of claim 1 wherein the thin film polyamide layer is further characterized by possessing a COOH/amide ratio of equal to or greater than 0.15, as measured by ATR IR.

5. The membrane of claim 1 wherein the thin film polyamide layer is further characterized by possessing a COOH/amide ratio of equal to or greater than 0.16, as measured by ATR IR.

6. The membrane of claim 1 wherein the thin film polyamide layer is further characterized by possessing an amino phenol/m-phenylene diamine ratio of at least 0.18.

7. The membrane of claim 1 wherein the thin film polyamide layer is further characterized by possessing:
i) an azo content of from 0.40% to 0.75 wt %;
ii) a dissociated carboxylate content of at least than 0.30 mol/kg of polyamide;
iii) a COOH/amide ratio of equal to or greater than 0.14; and
iv) amino phenol/m-phenylene diamine ratio of at least 0.18.

Assignees

• Dow Global Technologies Llc

Inventors

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

Classifications

• B01D2323/36

  Introduction of specific chemical groups · CPC title

• B01D71/56 Primary

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

• B01D2323/40

  in-situ membrane formation · CPC title

• B01D67/0093

  Chemical modification · CPC title

• B01D69/125

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