摘要:
A process for the preparation of linear polymers or block copolymers of styrene by anionic polymerization comprises carrying out the chain termination with an n-alkyl glycidyl ether or a dialkyl ketone.
摘要:
Block copolymers comprise at least two hard blocks S1 and S2 made from vinylaromatic monomers and, between these, at least one random soft block B/S made from vinylaromatic monomers and from dienes, where the proportion of the hard blocks is above 40% by weight, based on the total block copolymer.
摘要:
Elastomeric block copolymers comprising at least one hard block A composed of styrene monomers and at least one elastomeric block (B/A) composed of styrene monomers and dienes, the glass transition temperature Tg of the block A being more than 25° C. and that of block (B/A) being less than 25° C. and the phase volume ratio of block A to block (B/A) being chosen so that the proportion of the hard phase in the total block copolymer is from 1 to 40% by volume and the amount by weight of the diene is less than 50% by weight, and the relative proportion of 1,2 linkages of the polydiene, based on the sum of 1,2- and 1,4-cis/trans linkages, being below 15%, are prepared by anionic polymerization by means of a lithium alkyl in a nonpolar solvent in the presence of a soluble potassium salt and are used for the production of shaped articles.
摘要:
A process for the reaction of an organic compound in the presence of a catalyst comprising, as active metal, ruthenium alone or together with at least one Group Ib, VIIb, or VIIIb metal in an amount of from 0.01 to 30 wt %, based on the total weight of the catalyst, applied to a support, wherein from 10 to 50% of the pore volume of the support comprises macropores having a pore diameter in the range of from 50 nm to 10,000 nm and from 50 to 90% of the pore volume of the support comprises mesopores having a pore diameter in the range of from 2 to 50 nm, the sum of said pore volumes being 100%, and said catalyst as such.
摘要:
A process for the reaction of an organic compound in the presence of a catalyst comprising, as active metal, ruthenium alone or together with at least one Group Ib, VIIb, or VIIIb metal in an amount of from 0.01 to 30 wt %, based on the total weight of the catalyst, applied to a support, wherein from 10 to 50% of the pore volume of the support comprises macropores having a pore diameter in the range of from 50 nm to 10,000 nm and from 50 to 90% of the pore volume of the support comprises mesopores having a pore diameter in the range of from 2 to 50 nm, the sum of said pore volumes being 100%, and said catalyst as such.
摘要:
An elastomeric block copolymer comprising at least one block A having polymerized units of a vinylaromatic monomer and forming a rigid phase and at least one elastomeric block B/A having polymerized units of both vinylaromatic monomers and of a diene and forming a flexible phase, and glass transition temperature Tg of the block A being above 25.degree. C. and that of the block B/A being below 25.degree. C. and the phase volume ratio of block A to block B/A being chosen so that the amount of the rigid phase in the total block copolymer is 1 to 40% by volume and the amount of the diene is less than 50% by weight.
摘要:
Block copolymers comprise at least two hard blocks S1 and S2 made from vinyl aromatic monomers and, between these, at least ore random soft block B/S made from vinyl aromatic monomers and from dienes, where the proportion of the hard blocks is above 40% by weight, based on the total block copolymer, wherein the 1,2-vinyl content in the soft block B/S is less than 20%.
摘要:
A molding material comprises styrene/butadiene block copolymers obtainable by anionic polymerization and from 0.01 to 1% by weight, based on the polymer, of .alpha.-tocopherol.
摘要:
The invention relates to thermoplastic moulded masses containing, a) at least one block copolymer (A), comprising, with relation to (A), a1) 50 to 90 wt. % of at least one styrol monomer, a2) 10 to 50 wt. % of at least one diene monomer, with the following as stabilisers, relative to the moulded mass, b) 0.001 to 0.18 wt. % of at least one benzofuranone derivative (B), c) 0.05 to 1 wt. % of at least one organic phosphite (C), and d) 0.1 to 0.3 wt. % of at least one stabiliser compound (D), selected from sterically hindered phenols and aromatic amines.
摘要:
##STR1## where the individual radicals R are identical or different and are each hydrogen, an alkali metal, or ammonium which is unsubstituted or substituted by organic radicals, or are each C 1 -C 20 -alkyl or a polyoxyethylene radical which contains from 1 to 10 ethylene oxide units and whose terminal OH group may be etherified by an alcohol of 1 to 3 carbon atoms, are used as sun screen agents.