摘要:
The invention relates to a process for the preparation of optionally branched, high molecular weight polyarylene sulphides with melt viscosities which can be established at defined values and low corrosion.These polyarylene sulphides are obtained by reacting alkali metal sulphides, if appropriate mixed with alkali metal bisulphides and reaction accelerators, with dihalogenoaromatics and, if appropriate, polyhalogenoaromatics, with the addition of particular monohalogenoaromatics as chain stoppers.
摘要:
The invention relates to a process for the production of aromatic polycarbonates, aromatic polyester carbonates and aromatic polyesters by the known two-phase interfacial method which is characterized in that a mixture of aromatic hydrocarbons with alkanes and/or cycloalkanes is used as the organic phase and in that phosphines or phosphine oxides are used as the catalysts.
摘要:
This invention relates to a process for the preparation of high molecular weight, optionally branched polyarylenesulphides from alkali metal sulphides, optionally in admixture with alkali metal hydrogen sulphides and aromatic dihalogen compounds, in a polar solvent in the presence of from 0.1 to 6.0 mol-%, preferably from 0.25 to 4.0 mol-%, of an aromatic monoalkoxy or monoalkylthio compound. The polyarylenesulphides obtained have reproducibly adjustable melt viscosities and molecular weights and are distinguished by their reduced tendency to corrosion.
摘要:
Described is a process for producing segmented polyurethanes having improved processing characteristics in the melt state and an efficient spinning process based thereon to form highly elastic, fine linear density elastane yarn and filament having improved mechanical and thermal properties by using hydroxyalkyl-terminated polysiloxanes in combination with specific crosslinking-capable polyisocyanates in the reaction of long-chain high molecular weight polyhydroxy compounds with organic diisocyanates and low molecular weight diols and also optionally further auxiliary and additive substances in the melt.
摘要:
A process for modifying superabsorbent polymers is disclosed. The surface of a polymer containing hydrolyzed polyacrylonitrile in the form of particulates, is modified by crosslinking in a water/alcohol reaction mixture and in the presence of silica. The resulting product features improved absorbency under load and lesser degree of gel blocking.
摘要:
Super-absorbent polymer in the form of pre-formed spherical particles obtainable by alkaline hydrolysis of aqueous emulsions of crosslinked and/or un-crosslinked homopolymers and/or copolymers of acrylonitrile in water/alcohol mixtures and the use of the polymer in hygiene products, as a water-storing material in agriculture and for the sheathing of electrical cables.
摘要:
The present invention relates to a process for preparing polyisocyanates containing isocyanurate groups by trimerizing a portion of the isocyanate groups of an organic polyisocyanate component containing a) one or more diisocyanates corresponding to formula (1) ##STR1## wherein R represents a saturated, straight-chain, aliphatic hydrocarbon group having 8 to 15 carbon atoms and optionally b) up to 95 NCO equivalent-%, based on the total equivalents a) and b), of one or more organic polyisocyanates other than a), in the presence of trimerization catalysts and terminating the trimerization reaction at any desired degree of trimerization. The invention also relates to the polyisocyanates containing isocyanurate groups obtained by this process and to their use, optionally in excess starting polyisocyanates and optionally blocked with blocking agents for isocyanate groups, as an isocyanate component for preparing polyisocyanate addition products.
摘要:
The invention relates to new hexahydrotriazinetrione-containing high molecular weight polyarylene sulphides (PAS), preferably polyphenylene sulphides (PPS), and a process for their preparation.
摘要:
The invention relates to new, free-flowing polyamide molding compounds and blends, characterized in that they are prepared by mixing of polyamides known per se in the melt with low molecular weight, liquid-crystalline esters and/or ester amides corresponding to formula (I) and/or liquid-crystalline, oligomeric esters and/or ester amides corresponding to formula (II) and, optionally, other additives, at least one polymeric blending component being used as a further additive in the case of polyamide blends, and to the use of these liquid-crystalline (LC) additives I and/or II as flow promoters in polyamide molding compounds and blends and to a process for the production of the new polyamide molding compounds and blends. The invention also relates to the new oligomeric esters and/or ester amides corresponding to formula (II).