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:
A polyisobutene composition having a global maximum of the differential molecular weight distribution curve at a molecular weight Mmax of from 3 500 to 8 000 is described, which comprises at least one local maximum at a molecular weight of from 112 to 560. The isobutene oligomers present act as flow improvers and boiling assistants. They are added to higher molecular weight isobutene polymers, preferably before or in the course of a distillation, for removing unconverted isobutene and/or an inert diluent.
摘要:
Process of producing unvulcanized rubber useful for producing vulcanized rubber with improved hysteresis, which comprises mixing a composition comprising unvulcanized rubber, carbon black and xanthogen polysulfide at an elevated temperature in a non-productive stage and composition suitable for producing unvulcanized rubber useful for producing vulcanized rubber with improved hysteresis, which comprises unvulcanized rubber, a filler comprising carbon black and xanthogen polysulfide.
摘要:
This invention provides a polymer polyol composition (I) comprising a polyol (A) and polymer particles (B) dispersed in (A), the polymer particles (B) being formed by polymerizing an ethylenically unsaturated compound (b) in a polyol, wherein the content of (B) in (I) is from 35 to 75 mass %, based on the mass of (I), and the amount of soluble polymers (P) dissolved in (A) is not more than 5 mass %, based on the mass of (A), and provides methods for producing the polymer polyol composition (I). Further, this invention provides a method for producing a foamed or non-foamed polyurethane resin, which method comprises reacting a polyol component with a polyisocyanate component in the presence or absence of a blowing agent, wherein the above polymer polyol composition is used at least as a portion of the polyol component. A polymer polyol having a low viscosity and excellent dispersion stability is provided even when having a high concentration of polymer particles, and is used advantageously to produce polyurethane resins having excellent 25% ILD (hardness) and compression set, or foams thereof, with good operation efficiency.
摘要:
Polymers and copolymers synthesized by means that yield a narrow range of molecular weights can have different properties than polymers synthesized by conventional means. In order to obtain such polymers, however, polymerization must be controlled. One type of controlled polymerization is the reversible addition-fragmentation chain transfer (RAFT) process, which has characteristics of a living polymerization. The present invention discloses a group of dithioesters and trithioesters suitable as chain transfer agents for RAFT polymerization. The present invention also discloses RAFT polymerizations conducted in aqueous media.
摘要:
A reaction product (A) which can be prepared by reaction, under free radical conditions, of at least one monomer (a) capable of free radical reaction, in the presence of at least one free radical initiator and of a radical of the formula (III) 1 where R1 to R3, in each case independently of one another, are hydrogen, methyl or a radical-stabilizing and/or bulky group selected from an unsubstituted or substituted, linear or branched alkyl of two or more carbon atoms, cycloalkyl, alcohol, ether, polyether, amine, aralkyl radical, a substituted or unsubstituted aromatic, heterocyclic or olefinic hydrocarbon, a halogen atom, a substituted or unsubstituted, linear or branched alkenyl or alkynyl group, nullC(O)R5, nullC(O)OR5, nullCR5R6nullOnullR7, nullOnullC(O)R5, nullCN, nullOnullCN, nullSnullCN, nullOnullCnullNR5, nullSnullCnullNR5, nullOnullCR5R6nullCR7R8NR9R10, nullNnullCnullO, nullCnullNR5, nullCR5R6-Hal, nullC(S)R5, nullCR5R6nullP(O)R7R8, nullCR5R6nullPR7R8, nullCR5R6nullNR7R8, nullCR5R6(OR7)(OR8), nullCR5R6(OR7)(NR8), nullCR5R6(NR7)(NR8), an anhydride, acetal or ketal group, nullSO2R5, an amidine group, nullNR5C(S)NR6, nullNR5C(S)nullOR6, nullNnullCnullS, nullNO2, nullCnullNnullOH, nullN(R5)nullNR6, nullPR5R6R7, nullOSiR5R6R7 or nullSiR5R6R7, where R5 to R10, independently of one another in each case, are defined in the same way as R1 to R5, or two of the radicals R1 to R4 form a C4- to C7-ring which in turn may be substituted or unsubstituted and, if required, may contain one or more heteroatoms, with the proviso that at least two of the radicals R1 to R3 are a radical-stabilizing and/or bulky group as defined above, has various uses.
摘要:
The present invention relates to selected 1-alkoxy-2,2 diethyl-6,6 dimethyl piperidine and 1-alkoxy-2,6 diethyl-2,3,6 trimethyl piperidine derivatives which are substituted in the 4 position by an oxygen or nitrogen atom; a polymerizable composition comprising a) at least one ethylenically unsaturated monomer and b) said piperidine derivatives. Further aspects of the present invention are a process for polymerizing ethylenically unsaturated monomers, and the use of 1-alkoxy-2,2 diethyl-6,6 dimethyl piperidine and 1-alkoxy-2,6 diethyl-2,6 dimethyl piperidine derivatives which are substituted in the 4 position by an oxygen or nitrogen atom for controlled polymerization. The intermediate N-oxyl derivatives, a composition of the N-oxyl derivatives with ethylenically unsaturated monomers and a free radical initiator, as well as a process for polymerization are also subjects of the present invention.
摘要:
A subject of the present invention is an aqueous composition combining at least one block copolymer (A) comprising, in the pH and temperature conditions of the composition, at least two polyionic blocks of the same charge and at least one non-charged block, with at least one ionic or polyionic (B) type with an opposite charge to that of the said polyionic blocks, in the pH conditions of the composition; type (B) being chosen from among ions carrying at least two charges, surfactants carrying at least one charge, oligomers and/or polymers carrying at least two charges and/or mineral particles carrying at least two charges; the block copolymer (A) content being such that the viscosity of the composition is at least greater than three times that of an aqueous solution of block copolymer (A) and to that of an aqueous solution of type (B), in the same temperature, pH and concentration conditions. The present composition, before its use or during its use, is in the form of a gel.
摘要:
Control agents that have a nitrogen-nitrogen bond covalently bonded to a thiocarbonyl moiety are provided for living-type free radical polymerization of a wide variety of monomers. These control agents provide superior properties for control of the polymerization and/or the properties of the polymers obtained and/or the monomers that may be polymerized. In some embodiments, a bulky group is pendant off the activated thiocarbonyl portion of the control agents. Multifunctional control agents provide the opportunity for a variety of structurally unique polymers, including block copolymers, stars and hyper-branched polymers.
摘要:
For the preparation of a multimodal polymer at least one monomer is subjected to free radical polymerization in the presence of several alkoxyamines comprising the sequence of formula: 1 in which RL is a monovalent radical exhibiting a molar mass of greater than 15, A represents the core of the alkoxyamine and n is a non-zero integer, the alkoxyamines exhibiting different values of n.