| 摘要 |
PROBLEM TO BE SOLVED: To provide a process for making a microporous membrane from a polymer solution, and the resultant membrane. SOLUTION: A thermal assist, such as heating of the polymer solution, can be effected subsequent to the shaping of the polymer solution, such as by forming a film, tube or hollow fiber of the polymer solution under conditions that do not cause phase separation. In a preferred embodiment, the formed solution is briefly heated to thereby cause a temperature gradient through the body of the formed solution. The polymer in solution then is precipitated to form a microporous structure. Wide variety of symmetric and asymmetric structures can be formed using this process. A higher temperature and/or a longer heating time effected during the heating step result in larger pore sizes and different pore gradients in the final membrane product. COPYRIGHT: (C)2007,JPO&INPIT
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