SU1752418A1 - Method for preparation of compositional gas-separating membrane - Google Patents

Abstract

The invention relates to the plastics industry, in particular to methods for producing composite gas separation membranes, and can be used in the chemical, petrochemical, and gas extraction industries for the separation of gas mixtures. The invention improves the selectivity of the separation of gels and nitrogen by counting. The invention relates to the plastics industry, namely, to methods for producing composite gas separation membranes, and can be used in the chemical, petrochemical and gas industry to separate gels from gas mixtures. separation of gels and nitrogen, the porous substrate of poly-2,6-dimethyl-1,4-phenylene oxide is impregnated with a saturated Cg-Xu hydrocarbon or a mixture of C and Xu in a mass of respect 80:20. The liquid is removed from the surface of the membrane, after which an excess of a 1-3% solution of polyamidoimide of the general formula C-NH-R-NH O t is poured on it where n 140-210:) 10 7s30% or its equimolar complex with polyvinyl chloride nilpyrrolidone. The excess solution is drained and dried membrane. 1 z.p f-crystals, 1 tab. Example 1. From a 8% solution of poly-2,6-diphenyl-1,4-phenylene oxide in a mixture of chloroform-butanol (8515 weight) on a glass plate of 20 x 20 cm, a layer thickness of 350 µm is cast, immersed in a precipitation bath with ethanol for 30-50 minutes and then in a bath with a mixture of getan-decane (80–20 vol). incubated for 2 h and dried in air for 15 h. a and N) b CO

Description

A 3% solution of PAI-1 polyamidoimide in N-methylpyrrolidone (MP) is poured onto the microporous substrate thus obtained. Placing the membrane vertically, allow to drain the excess solution. The resulting membrane is dried at 40 ° C under vacuum. By visual assessment, the yellow PAI-1 layer was homogeneous and differed by good adhesion to the substrate. The membrane properties are listed in the table.

Examples 2-9 are made in the same way as Lrimer 1, but under the conditions indicated in the table using dimethylformamide dz (DMF) or dimethylacetamide (DMAA).

Examples 4,5 confirm the increase in the selectivity of the membrane when using instead of polyamidoimide its equimolecular complex with polyvinyl pyrrolidone (PVP), obtained by simultaneously dissolving the latter with PAI.

Examples 6-9 are controls and are outside the scope of the claims.

Polyamideimides of the general formula are used as a polymer.

ABOUT

when n 140-220, where

R X§X-0

PAI-1

PAI

0-L). thirty%

PAI-5

0

five

0

Example 10 (comparative).

The porous polypropylene substrate is impregnated with ethyl alcohol and a 3% solution of polydimethylsiloxane in chloroform is applied. The membrane is dried. The membrane capacity for oxygen is 4-10, for nitrogen - 2, cm3 / cm-cm. ND separation selectivity of 2.0.

Claims (2)

Invention Formula The method of obtaining a composite gas separation membrane by impregnating a porous polymer base with an organic liquid, an inert substrate with respect to the polymer, applying a 1-3% polymer solution in an organic solvent and drying, characterized in that, in order to increase the selectivity of separation of helium and nitrogen, a substrate of poly-2,6-dimethyl-1,4-phenylene oxide, which, after removal from the surface of the organic liquid, is applied a solution of polyamidoimide of the general formula -NH-R-NHj five five 0 where n 140-220; R.-O-Oili , AAG h Ovv04 yO y ° x 70% 30% or its equimolar complex with polyvinylpyrrolidone in an amide aprotic solvent not compatible with organic liquid. 2. A method according to claim 1, characterized in that saturated C hydrocarbons Cd-Xu or a mixture of hydrocarbons C and Xu in a weight ratio of 80:20 are used as the liquid inert to the polymer of the substrate.