초록 ▼

The present invention appreciates that compounds comprising nitrogen-containing moieties that are at least divalent (e.g., urea, urethane, amide, etc.) can be reacted with azides using at least radiation energy to initiate the reaction between at least a portion of the compounds and the azides to fo

The present invention appreciates that compounds comprising nitrogen-containing moieties that are at least divalent (e.g., urea, urethane, amide, etc.) can be reacted with azides using at least radiation energy to initiate the reaction between at least a portion of the compounds and the azides to form membranes that have surprisingly high selectivities for acid gases relative to nonpolar gases such as hydrocarbons. The membranes are also resistant to CO2 plasticization and have high acid gas flux characteristics. The resultant membranes can be extremely thin (e.g., 10 micrometers or less), which promotes high permeability for the acid gas and can translate into high productivity on a scaled-up, industrial level.

대표청구항 ▼

1. A method of making a membrane comprising: a) forming a solution comprising: i) a curable composition comprising: A) a thermoplastic polyurethane; andB) at least one azide crosslinking agent comprising two or more azide moieties that are co-reactive with the thermoplastic polyurethane, wherein the

1. A method of making a membrane comprising: a) forming a solution comprising: i) a curable composition comprising: A) a thermoplastic polyurethane; andB) at least one azide crosslinking agent comprising two or more azide moieties that are co-reactive with the thermoplastic polyurethane, wherein the azide crosslinking agent is present in an amount of no more than 15 wt. % of the total curable composition;ii) a solvent; andiii) a non-solvent;b) conducting a phase inversion of the solution to form a membrane structure; andc) exposing the membrane structure to ultraviolet or electron beam radiation so as to substantially cure the membrane structure and form a membrane. 2. The method of claim 1 wherein at least a portion of the membrane has an acid gas to hydrocarbon gas selectivity of at least 5 at a temperature of 10° C., wherein the membrane has a first major surface and a second major surface, and wherein selectivity is αA/B and selectivity is determined according to equation (EQ-a): αA/B=xA/yAxB/yB(EQ⁢-⁢a)wherein yA and yB are the molar concentrations of the acid gas and the hydrocarbon gas, respectively, in a mixed gas feed having a first pressure and that is proximal to the first major surface of the membrane, and xA and xB are the molar concentrations of acid gas and hydrocarbon gas, respectively, in a permeate gas mixture having a second pressure and that is proximal to the second major surface of the membrane, wherein the first pressure is greater than the second pressure. 3. The method of claim 1, wherein the thermoplastic polyurethane has at least one thermal transition temperature and wherein the membrane structure is at a temperature below one or more of the thermal transition temperatures for at a least a portion of the time period that the membrane structure is exposed to ultraviolet or electron beam radiation-so as to substantially cure the membrane structure and form a membrane. 4. The method of claim 1, wherein the membrane structure is at a first temperature for at least a portion of the forming time period, wherein the thermoplastic polyurethane has one or more thermal transition temperatures that are greater than the first temperature, and wherein the membrane structure is at a temperature below the one or more thermal transition temperatures that are greater than the first temperature for at a least a portion of the time period that the membrane structure is exposed to ultraviolet or electron beam radiation so as to substantially cure the membrane structure and form a membrane. 5. The method of any preceding claim, wherein the membrane comprises a first region adjacent to a second region, wherein the first region has a thickness of 10 micrometers or less and an acid gas to hydrocarbon gas selectivity of at least 5 at a temperature of 10° C., wherein the second region is permeable to fluid, wherein the membrane has a first major surface and a second major surface, and wherein selectivity is αA/B and selectivity is determined according to equation (EQ-a): αA/B=xA/yAxB/yB(EQ⁢-⁢a)wherein yA and yB are the molar concentrations of the acid gas and the hydrocarbon gas, respectively, in a mixed gas feed having a first pressure and that is proximal to the first major surface of the membrane, and xA and xB are the molar concentrations of acid gas and hydrocarbon gas, respectively, in a permeant gas mixture having a second pressure and that is proximal to the second major surface of the membrane, wherein the first pressure is greater than the second pressure. 6. The method according to claim 1, wherein the azide crosslinking agent comprises a compound represented by the following formula (N3)m—R10 wherein m is 1 to 6 and R10 is an m-valent moiety that may be aryl or nonaryl: saturated or unsaturated; linear or branched or cyclic; and/or substituted or unsubstituted. 7. The method according to claim 1, wherein the azide crosslinking agent comprises a compound represented by the following formula wherein each Ro and R11 independently is a divalent linking group that may comprise a heteroatom such as one or more of O, S, or P and that may be linear, branched, cyclic, polycyclic, fused ring, or the like; with the proviso that each Ro independently may be a single bond. 8. The method according to claim 1, wherein the azide crosslinking agent comprises a substituted or unsubstituted material according to the formula N3—(R13O)q—Ro—N3, wherein q is independently 1 to 10, R13 is independently a divalent alkylene moiety that may be linear, branched, cyclic, or polycyclic, and Ro independently is a divalent linking group that may comprise a heteroatom such as one or more of O, S, or P and that may be linear, branched, cyclic, polycyclic, fused ring, or the like; with the proviso that Ro independently may be a single bond. 9. The method of claim 1, wherein the thermoplastic polyurethane is based on polycaprolactone polyol. 10. The method according to claim 9, wherein the thermoplastic polyurethane comprises a poly(ester-urethane).