摘要:
The present invention discloses methods of separating gases using high performance UV cross-linked polymer functionalized molecular sieve/polymer mixed matrix membranes (MMMs) with either no macrovoids or voids of less than several angstroms at the interface of the polymer matrix and the molecular sieves. These UV cross-linked MMMs were prepared by incorporating polyethersulfone (PES) functionalized molecular sieves such as AIPO-14 and UZM-25 small pore microporous molecular sieves into a continuous UV cross-linkable polyimide polymer matrix followed by UV cross-linking. The UV cross-linked MMMs in the form of symmetric dense film, asymmetric flat sheet membrane, or asymmetric hollow fiber membranes have good flexibility, high mechanical strength, and exhibit significantly enhanced selectivity and permeability over polymer membranes made from corresponding continuous polyimide polymer matrices for carbon dioxide/methane and hydrogen/methane separations. The MMMs of the present invention are suitable for a variety of liquid, gas, and vapor separations.
摘要:
The present invention discloses a novel method to improve the selectivities of polybenzoxazole (PBO) membranes prepared from aromatic polyimide membranes for gas, vapor, and liquid separations. The PBO membranes that were prepared by thermal treating aromatic polyimide membranes containing between 0.05 and 20 wt-% of a poly(styrene sulfonic acid) polymer. These polymers showed up to 95% improvement in selectivity for CO2/CH4 and H2/CH4 separations compared to PBO membranes prepared from corresponding aromatic polyimide membranes without a poly(styrene sulfonic acid) polymer.
摘要:
Mixed matrix membranes that are capable of separation and purification of gas mixtures are disclosed. These membranes comprise polymers that include dispersed therein nanomolecular sieve particles. In a preferred embodiment, the nanomolecular sieve particles contain attached functional groups to prevent their agglomeration.
摘要:
A thin film composite membrane comprises a core layer and a sheath UV-crosslinked polymer layer. The thin film composite membrane is produced by the co-extrusion of two polymer solutions. The core layer and the sheath layer can be separately optimized. The sheath layer may be UV-crosslinked to provide stability and selectivity at the desired operating temperature of the composite membrane.
摘要:
The present invention involves the use of a multi-stage membrane system for gas, vapor, and liquid separations. In this multi-stage membrane system, high selectivity and high permeance or at least high selectivity polybenzoxazole membranes or cross-linked polybenzoxazole membranes are applied for a pre-membrane or both the pre-membrane and the secondary membrane. A primary membrane can be from conventional glassy polymers. This multi-stage membrane system can reduce inter-stage compression cost, increase product recovery and product purity for gas, vapor, and liquid separations. It can also save the cost compared to the system using all the high cost polybenzoxazole membranes or cross-linked polybenzoxazole membranes.
摘要:
In the present invention high performance cross-linked polybenzoxazole and polybenzothiazole polymer membranes and methods for making and using these membranes have been developed. The cross-linked polybenzoxazole and polybenzothiazole polymer membranes are prepared by: 1) first synthesizing polyimide polymers comprising pendent functional groups (e.g., —OH or —SH) ortho to the heterocyclic imide nitrogen and cross-linkable functional groups in the polymer backbone; 2) fabricating polyimide membranes from these polymers; 3) converting the polyimide membranes to polybenzoxazole or polybenzothiazole membranes by heating under inert atmosphere such as nitrogen or vacuum; and 4) finally converting the membranes to high performance cross-linked polybenzoxazole or polybenzothiazole membranes by a crosslinking treatment, preferably UV radiation. The membranes can be fabricated into any convenient geometry. The high performance cross-linked polybenzoxazole and polybenzothiazole polymer membranes of the present invention are suitable for a variety of liquid, gas, and vapor separations.
摘要:
A new family of silicon-based polymers has been prepared in which organic host components are bound covalently. The polymer is a polysilsesquioxane matrix comprising, for example, hosts such as cyclodextrins (CD) or calixarenes (CX).
摘要:
The present invention discloses blend polymer membranes comprising thermally rearranged polymers derived from aromatic polyimides containing ortho-positioned functional groups and methods for making and using these blend polymer membranes. The blend polymer membranes described in the current invention are prepared by heat treatment of blend polymer membranes comprising aromatic polyimides containing ortho-positioned functional groups such as —OH or —SH groups. In some instances, an additional crosslinking step is performed to improve the selectivity of the membrane. These blend polymer membranes have improved flexibility, reduced cost, improved processability, and enhanced selectivity and/or permeability compared to the comparable polymer membranes that comprise a single polymer.
摘要:
The present invention discloses a novel method to improve the selectivities of polybenzoxazole (PBO) membranes prepared from aromatic polyimide membranes for gas, vapor, and liquid separations. The PBO membranes that were prepared by thermal treating aromatic polyimide membranes containing between 0.05 and 20 wt-% of a poly(styrene sulfonic acid) polymer. These polymers showed up to 95% improvement in selectivity for CO2/CH4 and H2/CH4 separations compared to PBO membranes prepared from corresponding aromatic polyimide membranes without a poly(styrene sulfonic acid) polymer.
摘要:
Metal-organic framework (MOF)-polymer mixed matrix membranes (MOF-MMMs) have been prepared by dispersing high surface area MOFs (e.g. IRMOF-1) into a polymer matrix (e.g. Matrimid 5218). The MOFs allow the polymer to infiltrate the pores of the MOFs, which improves the interfacial and mechanical properties of the polymer and in turn affects permeability. Pure gas permeation tests show the incorporation of 20 wt-% of IRMOF-1 in Matrimid 5218 polyimide matrix results in 280% improvement in CO2 permeability without a loss of CO2/CH4 selectivity compared to those of the pure Matrimid 5218 membrane. This type of MOF-MMMs has significantly improved gas separation performance with dramatically high CO2 permeability (>35 barrer) and higher than 29 CO2/CH4 selectivity at 50° C. under 100 psig pressure, which are attractive candidates for practical gas separation applications such as CO2 removal from natural gas.