摘要:
The invention relates to an initiator composition for anionic polymerization, comprising at least one alkali metal hydride selected from LiH, NaH, and KH, and at least one organylaluminum compound, and to a process for the anionic polymerization of styrene monomers or of diene monomers using the initiator composition.
摘要:
A process for preparing impact-resistant molding compositions by anionic polymerization of vinylaromatic monomers in the presence of a rubber, in a continuous-flow reactor cascade composed of at least two reactors, where the vinylaromatic monomers are fed in substreams to the reactors of the reactor cascade, and an anionic initiator and a rubber are fed at least to the first reactor, and where the reactor cascade is composed of back-mixing reactors.
摘要:
In a process for polymerizing dienes in a solvent comprising vinylaromatic monomers, the polymerization is carried out in the presence of a metal compound of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo or W as catalyst and a Lewis acid as cocatalyst and, if desired, an alkylating agent and, if desired, a regulator. This process can be used for preparing high-impact polystyrene, acrylonitrile-butadiene-styrene copolymers or methyl methacrylate-butadiene-styrene copolymers.
摘要:
Polyamide whose main chain contains a chemically bound N-alkyllactam, and processes for preparing such a polyamide and fibers, films and moldings comprising such a polyamide.
摘要:
Thermoplastic molding materials comprising A) 10 to 99.99% by weight of a polyoxymethylene homo- or copolymer, B) 0.01 to 5% by weight of an imidazole of the general formula where the R1 to R4 radicals are each independently defined as follows: R1 is an alkyl radical having 1 to 5 carbon atoms, R2 to R4 are each hydrogen, an alkyl radical having 1 to 5 carbon atoms, C) 0 to 5% by weight of an alkaline earth metal oxide, D) 0 to 80% by weight of further additives, where the sum of the percentages by weight of components A) to D) adds up to 100%.
摘要:
The present invention relates to coated polyoxymethylene moldings comprising at least one polyoxymethylene homo- or copolymer A), and also, if appropriate, further additives B), which has been coated on the surface with at least one binder C) and one formaldehyde scavenger D), wherein the binder C) used comprises a polyalkylene oxide C1 or a polyvinyl ester C2 or a graft polymer C3 composed of C1 and C2 or a mixture of these, and the formaldehyde scavenger D) used comprises at least one imidazolidin-2-one compound.
摘要:
The invention relates to a process for working up particulate crude polyoxymethylene, which comprises the following steps: (a) introduction of the particulate crude polyoxymethylene into an extraction column (13) operated at a pressure in the range from 1 to 6 bar, (b) introduction of a polar extractant into the extraction column (13) with a temperature in the range from 95 to 140° C. and a pressure in the range from 1 to 6 bar, wherein from 10 to 1000 ppm, based on the amount of polar extractant introduced, of a buffer substance which buffers in the pH range from 7.5 to 11.5 are introduced into the extraction column (13).
摘要:
Polyamide containing a compound which bears at least one hydroxy group and has chemical bonding by way of an amide group to the end of the polymer chain, process for preparing this polyamide, and also fibers, films, and moldings, comprising at least one such polyamide.
摘要:
The invention relates to a polyoxymethylene (POM) powder for use in a selective laser sintering process and having the following parameters: Isothermal crystallization time (at 152° C.)>3 min Mnfrom 22 000 to 25 000 g/mol Mwfrom 60 000 to 140 000 g/mol Mw/Mnfrom 3 to 5 MVRfrom 15 to 70 [cm3/10 min] d50 average particle size60 μm Particle sizefrom 30 to 130 μm. A process for producing the powder, and also moldings produced from this powder by a selective laser sintering process, are also described.
摘要:
A continuous process for producing polyamides, their oligomers or mixtures thereof, if appropriate with further reaction products, comprises reaction of aminonitriles or dinitriles and diamines or mixtures thereof, if appropriate together with further polyamide-forming monomers and/or oligomers, with an aqueous medium composed of aqueous monomer and oligomer extracts obtained from polyamide production by extraction of the polymer with water in a reactor which has a vertical longitudinal axis and through which there is a flow substantially in the longitudinal direction wherein water and/or the aqueous medium are introduced into the reactor at two or more different locations along the vertical longitudinal axis, wherein the aqueous medium is introduced at one or more locations.