Abstract: An ultrathin film composed substantially of silicon-containing polyurea comprising polyaddition bonded units derived from(A) at least one polyamine selected from the group consisting of silicon-containing polyamines and hydrocarbon-type polyamines, each of said polyamines containing at least two primary or secondary amino groups in the molecule, and(B) at least one polyisocyanate compound selected from the group consisting of silicon-containing polyisocyanates and hydrocarbon-type polyisocyanates, each of said polyisocyanates having at least two isocyanate groups in the molecular chains;provided that when the polyisocyanate compound is the hydrocarbon-type polyisocyanate alone, at least one of the selected polyamines is a silicon-containing polyamine containing at least one terminal amino group in the molecule.

Abstract: A permselective membrane comprising a thin permselective film of a polymeric material, said polymeric material being prepared by cross-linking a polyaddition product between a polyepoxy compound and a polyamino compound having at least two amino groups capable of reacting with epoxy groups with a polyfunctional compound selected from the group consisting of aromatic, heterocyclic and alicyclic compounds containing at least two functional groups selected from acid halide, sulfonyl halide, isocyanate and acid anhydride groups; and a process for producing the same. The permselective membrane of this invention is especially useful for desalination of saline or brackish water by reverse osmosis.

Abstract: Novel substantially linear, or at least partially cross-linked, nitrogen-containing polymers having an aryleneimine or arylenether unit in the main chain with an amino group or a group derived from it being bonded as a pendant group to a nuclear carbon atom of the arylene group of the above unit. According to the number and type of the pendant groups, the polymers can have various useful properties such as thermal stability, hydrophilicity, oxidative reducibility, photosensitivity, color formability or the ability to form coordination bonds. Furthermore, the polymers have good solubility in aprotic polar organic solvents. Permselective membranes having good performance can be prepared from solutions of the polymers in these solvents.

Abstract: Novel aromatic polymers containing a nitrogen-containing ring group which comprises at least 30 mol% of a recurring unit of the formula ##STR1## Preferably,, the nitrogen-containing ring group ##STR2## is a benzimidazolone, benzimidazolthione, benzimidazole, quinoxalidinedione, benzotriazole, benzothiazolidine, benzothiadiazolidine-S-oxide, benzothiadiazolidine-S-dioxide, benzodithiadiazine, benzodiazophosphole-p-oxide, benzodiazophosphole, benzodiazosilole, or benzodiazoborole ring.These polymers are soluble in various polar solvents. They find a wide range of applications ascribable to these ring groups, for example, as thermally stable resins and permselective membranes. These polymers can be prepared by reacting substantially linear aromatic polymers comprising at least 30 mol% of a recurring unit of the formula ##STR3## with reagents capable of forming 5- or 6-membered nitrogen-containing rings.

Abstract: Novel aromatic imine polymers containing as at least a part of its entire recurring units an aromatic imino group ##STR1## wherein .phi. is an aromatic ring group having a valence of at least two and has at least one electron-attracting group with respect to the group ##STR2## and R.sub.1 is a hydrogen atom or a non-aromatic hydrocarbon residue having a valence of at least 1. These polymers find a wide variety of applications by utilizing their thermal stability and various other desirable properties such as reducibility or photosensitivity. The polymers are prepared by reacting specific aromatic dihalogen compound with specific difunctional amino-containing compounds in an inert organic solvent in the presence of an acid acceptor. Copolymers can be obtained by carrying out the reaction using specific difunctional comonomers.