| 摘要 |
<p>1422767 Polypiperazimide membranes MONTEDISON SpA 7 May 1974 [7 May 1973] 19946/74 Heading B5B [Also in Division C3] A reverse osmosis anisotropic membrane is east from a solution of a polypiperazinamide which has units (I) where x s 0-8, R is any substituent, and A is a dicarbonyl radical being, in some of all of the units (I), (II) where R<SP>1</SP> and R<SP>11</SP> are H, alkyl, or aryl, and X is O or S. x and R may differ in different units. Optional units A include The substituents R may be arranged in any steric position in the piperazine ring, so that the substituted piperazine groups can be arranged cis- or trans-. The membrane is formed from the solution by (a) casting, (b) partially evaporating the solvent, and (c) coagulating by immersion in water, and optionally heat-treating. The solvent may be an alkyl amide, sulphoxide, or sulphone. Also present may be LiCl, LiNO 3 , LiBr, CaCl 2 , ZnCl 2 , MgCl, or MgClO 4 , or water. Before casting, the solution may be heated to from 70‹ C. to the b.p. of the solvent. The evaporation may be performed at 70-200‹ C., the coagulation at 0-30‹ C., and the heat-treatment in water at 60-100‹ C. The casting support may be flat or tubular and may be of glass, metal, polyethylene terephthalate, PTFE, woven or non-woven fabric, or paper; it may be porous. The coagulation bath water may contain NaCl, CaCl 2 , alcohols, or acetone. The membranes may be flat, tubular, or in the form of hollow fibres.</p> |
