Isotropic microporous syndiotactic polystyrene membranes and processes for preparing the same
First Claim
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1. A semi-permeable membrane comprising a thin isotropic syndiotactic polystyrene microporous membrane.
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Abstract
This invention relates to semi-permeable isotropic syndiotactic polystyrene microporous membranes and processes for preparing such membranes.
105 Citations
21 Claims
- 1. A semi-permeable membrane comprising a thin isotropic syndiotactic polystyrene microporous membrane.
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9. A process for preparing a semi-permeable isotropic syndiotactic polystyrene microporous membrane comprising the steps of;
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A. forming a mixture comprising; (i) syndiotactic polystyrene, and (ii) at least one solvent for the syndiotactic polystyrene; B. heating the mixture to a temperature under conditions such that a homogeneous fluid is formed which possesses sufficient viscosity to be formed into a membrane; C. extruding or casting the homogeneous fluid into a membrane; D. quenching or coagulating the membrane by passing the membrane through one or more zones under conditions such that the membrane solidifies; and E. simultaneously or consecutively leaching the membrane by passing the membrane through one or more zones under conditions such that at least a substantial portion of the solvent for the syndiotactic polystyrene is removed from the membrane; wherein the semi-permeable membrane so formed possesses isotropic microporous structure.
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10. A process for preparing a semi-permeable isotropic syndiotactic polystyrene microporous membrane comprising the steps of;
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A. forming a mixture comprising; (i) syndiotactic polystyrene, (ii) at least one solvent for the syndiotactic polystyrene, and (iii) at least one non-solvent for the syndiotactic polystyrene; B. heating the mixture to a temperature under conditions such that a homogeneous fluid is formed which possesses sufficient viscosity to be formed into a membrane; C. extruding or casting the homogeneous fluid into a membrane; D. quenching or coagulating the membrane by passing the membrane through one or more zones under conditions such that the membrane solidifies; and E. simultaneously or consecutively leaching the membrane by passing the membrane through one or more zones under conditions such that at least a substantial portion of the solvent and non-solvent for the syndiotactic polystyrene is removed from the membrane; wherein the semi-permeable membrane so formed possesses isotropic microporous structure. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification