摘要:
A coherent explosive gas phase in a gas/liquid reactor comprising a tubular body which is closed at the top and into which one or more jets of liquid which are fed from a liquid circulation and are directed downward, emerge from one or more nozzles located at the highest point of the reactor, and entrain a gas phase which is to be dispersed, introduce it into the liquid and finally produce complete dispersion of the gas, is avoided by a method wherein, before start-up of the liquid circulation, the inactive reactor is charged with an amount of liquid reactant such that a gas space corresponding to the subsequent gas hold-up of dispersed bubbles under operating conditions remains at the top of the reactor, this gas space is filled with a gas, at a pressure p.sub.1, which is inert under the reaction conditions, and the gaseous reactant is fed to the reactor only when, under the action of the liquid jet or jets, the inert gas has been dispersed into a hold-up of dispersed bubbles so that a coherent gas phase no longer exists.
摘要:
High molecular weight polyphenylene ethers are prepared from monohydric phenols by a conventional polycondensation, by a method in which the resulting polymers are reacted with an epoxide of the general formula (I) ##STR1## where R.sup.1 and R.sup.2 can be identical or different and are each alkyl, cycloalkyl, aryl, aryloxy, alkoxy or carboxyalkyl, each of which may contain a further epoxide group, or C.sub.3 -C.sub.20 -alkyl-substituted amino, or R.sup.1 is hydrogen and R.sup.2 is one of the above groups, or R.sup.1 and R.sup.2 form part of a cycloalkyl ring.
摘要:
Wholly aromatic polyesters which form a liquid-crystalline fiber-forming melt below 300.degree. C. and are composed of(a) from 10 to 25 mol % of repeat units of the formula I ##STR1## (b) from 5 to 15 mol % of repeat units of the formula II ##STR2## (c) from 5 to 15 mol % of repeat units of the formula III ##STR3## (d) not less than 10 mol % of repeat units of the formula IV ##STR4## and (e) a molar amount corresponding to the total amount of (a), (b) and (c) of repeat units of the formula V ##STR5## the molar proportions of components a, b, c, d and e adding up to 100 mol % in each case, the preparation thereof and fibers, films, moldings and surface coatings prepared therefrom.
摘要:
Transparent, impact-resistant thermoplastic molding materials produced from a rigid methylmethacrylate polymer A, a rigid styrene-acrylonitrile polymer B and a flexible graft copolymer C, made from grafting an alkylmethacrylate and optionally styrene onto a rubber grafting base.
摘要:
Thermoplastic molding materials contain(A) from 5 to 95% by weight of a nylon and(B) from 5 to 95% by weight of a copolymer composed of(B.sub.1) from 50 to 99.9% by weight of a styrene of the general formula I ##STR1## where R.sup.1 is alkyl or 1 to 4 carbon atoms or hydrogen, R.sup.2 is alkyl of 1 to 6 carbon atoms or halogen and m is 0, 1, 2 or 3,(B.sub.2) from 0.1 to 30% by weight of a monomer containing epoxide groups (II) ##STR2## or of a monomer containing lactam groups (III) ##STR3## or of a monomer containing halobenzyl groups (IV) ##STR4## where R.sup.3 is a divalent, branched or straight-chain alkyl group of 2 to 15 carbon atoms, R.sup.4 is alkyl of not more than 6 carbon atoms, X is halogen, n is 1, 2 or 3 and r is 0, 1, 2 or 3, and(B.sub.3) from 0 to 48% by weight of further comonomers.
摘要:
A thermoplastic molding material contains 50-90% by weight of a hard component A comprising one or more copolymers of styrene and/or .alpha.-methylstyrene with acrylonitrile, and 50-10% by weight of a graft copolymer B comprising 40-80% by weight of a crosslinked acrylate polymer which has a mean particle size greater than 0.8 .mu.m (d.sub.50 value of the cumulative mass distribution) and onto which 20-60% by weight of a mixture of styrene and acrylonitrile in a weight ratio of from 88:12 to 65:35 is grafted.The novel molding material is used for the production of moldings.
摘要:
A process for the preparation of high molecular weight polyphenylene ethers from monohydric phenols which have alkyl substituents in both ortho-positions and may additionally have an alkyl substituent in one meta-position but not in the para-position, by an oxidative coupling reaction, employing oxygen, at from 10.degree. to 25.degree. C., in the presence of a catalyst complex comprising a copper salt and an N-substituted imidazole, in the presence of an aromatic C.sub.8 -C.sub.10 -hydrocarbon solvent.N-Methylimidazole, N-ethylimidazole, N-isopropylimidazole, N-n-butylimidazole, N-cyclohexylimidazole, N-octylimidazole and N-phenylimidazole are preferably used as the imidazole, advantageously in amounts of from 0.5 to 5 percent by weight.
摘要:
Thermosplastic molding materials which contain styrene polymers and polyphenylene ethers whose phenolic hydroxyl groups have been reacted with reactive copolymers.