| 摘要 |
<p>The present invention is directed to a multi-block polymeric material comprising a first amide acid prepolymer, made by combining A) a diamine with B) a dianhydride or its corresponding tetraacid or diacid-diester in an A/B mole ratio ranging from about 2.0 to 1.05, preferably about 2.0 to 1.1, chain extended with a second, different, compatible prepolymer selected from the group of prepolymers comprising A) a dianhydride or its corresponding tetraacid or diacid-diester combined with a monomer selected from B) epoxy, diisocyanate and polyester in an A/B mole ratio ranging from about 2.0 to 1.05, preferably about 2.0 to 1.1. The present invention is also directed to membranes of the above recited multi-block polymeric materials, especially membranes comprising thin, dense films of said multi-block polymeric material deposited on a micro-porous support layer producing a thin film composite membrane. The membranes of the multi-block polymeric material, especially the thin film composite membranes, are useful for separating aromatic hydrocarbons from mixtures of same with non-aromatic hydrocarbons under perstraction or pervaporation conditions.</p> |
