Microporous polyamide-imide membranes
Microporous polyamide-imide membranes and methods for making them are disclosed. The microporous membrane includes polyamide-imide polymer, wherein the membrane has an HFE bubble point, and an IPA flow-time. The microporous membrane has an HFE bubble point from about 25 psi to about 200 psi and has an IPA flow-time from about 400 second to about 40,000 seconds. Another microporous polyamide-imide membrane includes a polyamide-imide polymer, wherein the membrane has a HFE bubble point from about 25 psi to about 200 psi. The membrane is asymmetric- and has a tight layer with a thickness of ≤10 microns. Filter and purification devices incorporating such devices are also disclosed.
1. A membrane comprising:
a polyamide-imide polymer;
wherein the membrane has an HFE (hydrofluoroether) mean bubble point from about 25 psi to about 200 psi, wherein the HFE mean bubble point is determined using ASTM F316-03(2011) with ethoxy-nonafluorobutane (HFE-7200); and
the membrane is microporous, asymmetric and has a tight layer with a thickness of ≤10 microns.
2. The membrane of claim 1 , wherein the HFE bubble point is in a range from about 25 psi to about 150 psi.
3. The membrane of claim 1 , having an HFE bubble point from about 25 psi to about 100 psi.
4. The membrane of claim 1 , further having an IPA flow time in a range from about 400 seconds to about 40,000 seconds, wherein the IPA flow time is the time to flow 500 ml of isopropyl alcohol at a temperature of 21° C. and a pressure of 0.1 MPa through a 47 mm disk of the membrane having an area of 12.5 cm 2 .
5. The membrane of claim 4 , wherein the IPA flow time is in a range from about 2800 second to about 11,000 seconds.
6. The membrane of claim 1 , wherein the tight layer has a thickness of less than about 8 microns.
7. The membrane of claim 1 , wherein the membrane has a calcium metal capacity of at least 95 nanograms per centimeter squared of membrane.
8. The membrane of claim 1 , wherein the membrane has a zinc metal capacity of at least 5.9 nanograms per centimeter squared of membrane.
9. The membrane of claim 1 , wherein the membrane has a sodium metal capacity of at least 31 nanograms per centimeter squared of membrane.
10. A filter device comprising:
a filter incorporating a membrane comprising a polyamide-imide polymer;
wherein the membrane has an HFE (hydrofluoroether) mean bubble point from about 25 psi to about 200 psi, wherein the HFE mean bubble point is determined using ASTM F316-03(2011) with ethoxy-nonafluorobutane (HFE-7200); and
the membrane is microporous, asymmetric and has a tight layer with a thickness of ≤10 microns.