摘要:
A three-step process for the production of solventless polycarbonate is disclosed. Accordingly, a mixture of two different oligocarbonates each prepared by the interfacial method, is prepared in the first process step. In a second step, the mixture is crystallized. The third step entails polycondensation. In an additional embodiment of the invention the first step uses a mixture of one oligocarbonate with a suitable monomer.
摘要:
The novel thermotropic polycarbonates having recurring structural units of the formulae ##STR1## have good mechanical properties and good processability. They can be used in conventional manner for manufacturing mouldings, filaments, fibres and films.
摘要:
The new thermotropic polyesters containing recurring structural units corresponding to the following formulae ##STR1## show excellent mechanical properties and good processibility. They may be used in the usual way for the production of moldings, filaments, fibers and films.
摘要:
A process for purifying aromatic carbonate polymers, including polycarbonates and polyestercarbonates, is disclosed. Accordingly, a carbonate polymer is an organic solvent is rendered virtually free of low molecular weight components by agitation with aluminosilicate or by passing through layers of such aluminosilicate. The aluminosilicate is subsequently separated off and the carbonate polymer is isolated in known methods.
摘要:
The invention relates to a process for the synthesis of bis-(4-hydroxyphenyl)-alkanes on ion-exchange resins or mixtures of ion-exchange resins which are modified with alkyl-SH groups, wherein the monophenols and carbonyl compounds to be used have first been purified to remove substances which can transfer alkyl groups.
摘要:
The thermotropic aromatic polyesters according to the invention which contain recurring units corresponding to the following formulae ##STR1## show improved resistance to chemicals, low melting points and, hence, good processibility in addition to the well-known favorable mechanical properties of liquid-crystal materials. The thermotropic aromatic polyesters are used for the production of moldings, filaments, fibers and films.
摘要:
A process for producing an aliphatic-aromatic polycarbonate is disclosed. The process comprise (A) reacting in an anhydrous neutral solvent (i) an oligocarbonate of diphenol with (ii) an aliphatic dicarboxylic acid, and (B) eliminating the hydrogen chloride and carbon dioxide by-products. The oligocarbonate of diphenol is characterized in that it is terminated by chlorocarbonic acid ester groups. The resins thus prepared are readily molded conventionally.
摘要:
Process for the preparation of polyaromatic compounds in which an aromatic dichloro compound, optionally in the presence of an anhydrous aprotic solvent, is reacted with metallic zinc, manganese or magnesium in the presence of a catalyst system of(1) from 0.1 to 25 mol-% (based on the dihalogen compound) of a nickel salt, nickel complex salt or nickel complex,(2) from 2 to 100 mol per mol of nickel in (1) of a triarylphosphine and optionally(3) from 0.1 to 10 mol per mol of nickel (1) of a halide, sulphate or phosphate of an alkali metal, alkaline earth metal, zinc, magnesium or manganese.
摘要:
This invention relates to a process for the preparation of polyimide esters starting from trimellitic acid anhydride and aminophenols or aminohydroxy biphenyls.
摘要:
The invention relates to a method and digital storage medium and a computer system for multilingual associative searching. The method, medium or system provides for input of the search text in a first language, the search text is automatically translated into a second language, the search text translated into the second language is transferred to an associative search module, the associative search module including a neural network or a predefined algorithm which is designed to search on the basis of a search text in the second language.