Patent ID: 11931697
Assignee: DOW GLOBAL TECHNOLOGIES LLC
Field: Chemical engineering (Chemistry)
Classification: CPC B  Y | IPC B

Claim 0:
1. A method of making a carbonized polyvinylidene chloride copolymer film or a carbonized hollow fiber, the method comprising,
(a) providing a polyvinylidene chloride copolymer film having a thickness of 1 micrometer to 250 micrometers or a hollow fiber having a diameter of 1 micrometer to 250 micrometers,
(b) heating the polyvinylidene chloride copolymer film or the hollow fiber to a pretreatment temperature of 100° C. to 180° C. to form a pretreated polyvinylidene chloride copolymer film or a pretreated hollow fiber while restraining the polyvinylidene chloride copolymer film or the hollow fiber, and
(c) heating the pretreated polyvinylidene chloride copolymer film or the pretreated hollow fiber to a maximum pyrolysis temperature from 350° C. to 750° C. to produce the carbonized polyvinylidene chloride copolymer or the carbonized hollow fiber while restraining the pretreated polyvinylidene chloride copolymer film or the pretreated hollow fiber,
wherein the restraining of steps (b) and (c) is conducted by applying a compressive force,
wherein the carbonized polyvinylidene chloride copolymer film or the carbonized hollow fiber has an average pore size greater than a diameter of a large gas molecule larger than hydrogen gas determined by gas adsorption employing gas probe molecules of differing sizes, and
wherein the carbonized polyvinylidene chloride copolymer film or the carbonized hollow fiber has a hydrogen permeance in combination with a hydrogen/methane selectivity, wherein the combination of hydrogen permeance and hydrogen/methane selectivity is (i) at least 30 Gas Permeation Unit (GPU) hydrogen permeance and at least 200 hydrogen/methane selectivity or (ii) at least 10 GPU hydrogen permeance and at least 700 hydrogen/methane selectivity.