摘要:
Thermoplastic elastomer blends of alpha-olefin polymers and copolymers, such as polypropylene, having a melting point of at least 90.degree. C. with hydrogenated diblock copolymers of 1,4-polybutadiene and 1,2-polybutadiene have good physical properties such as low brittle point, good impact resistance at low temperatures, minimum creep at high temperatures, good elongation, good tensile and tear strengths and good impact strength. The blends can be repeatedly processed and still maintain good physical properties. The amount of alpha-olefin polymer or copolymer in the blend may range from about 10 percent to 60 percent, preferably 15 percent to about 48 percent with the amount of the hydrogenated butadiene block copolymer correspondingly ranging from about 90 percent to about 40 percent, preferably 85 percent to about 52 percent based on the combined weight of the two components. The blends are mixed at temperatures at least as high as the melting point of the alpha-olefin polymers or copolymer.
摘要:
The process described herein involves the preparation of block copolymers of the S-B-S type wherein S represents a block of polystyrene and B represents a block of polybutadiene. In order to have the initial polystyrene block soluble in the polymerization medium, cyclohexane and aromatic hydrocarbons have been used as the diluent or solvent in these polymerizations. The present process permits the use of hexane as diluent by having dissolved therein prior to polymerization a small amount of the S-B-S type of block copolymer being produced in the polymerization. Advantageously this solution used as the polymerization medium is prepared merely by washing the reactor used in a previous polymerization for production of the same type of S-B-S block copolymer with hexane to dissolve solid residues of S-B-S block copolymer deposited on the wall or agitator of the reactor. This hexane solution is then retained in the reactor to serve as the medium for the next polymerization batch. The dissolved S-B-S copolymer serves as a suspension agent for dispersion of the initial polystyrene block.
摘要:
1,3-Butadiene is polymerized in hexane solution in the presence of a catalyst composition comprising:(a) A hexane-soluble cobalt component;(b) A reducing agent comprising RAlX.sub.2 wherein R is a hydrocarbyl radical of 1-8 carbon atoms, and X is halogen; and(c) MgCl.sub.2, MgBr.sub.2, MnCl.sub.2, MnBr.sub.2 or a Mg or Mn salt of a carboxylic acid having 12-25 carbon atoms.The cobalt component may be a cobalt salt of a carboxylic acid or thiocarboxylic acid having at least six carbon atoms or a hexane-soluble complex of a cobalt salt with an oxygen-containing or nitrogen-containing group either in the same salt molecule or in a separate compound. Typical aluminum hydride or hydrocarbyl dihalides that may be used are aluminum hydride dichloride, ethyl aluminum dichloride, butyl aluminum dibromide, etc. Butadiene polymers having a high cis-1,4 and low 1,2 contents are obtained in high yield, and it is possible to produce high molecular weight polymers without the gel formation often accompanying such high molecular weight polymers.
摘要:
The catalyst system disclosed herein comprises one suitable for the polymerization of a conjugated diene, which system comprises a trihydrocarbyl aluminum compound, in which the hydrocarbyl group is an alkyl, aryl or cycloalkyl radical of 1-10 carbon atoms, and an alkali metal compound of the formula M--Y--R wherein M represents Li, Na or K; Y represents O, S or NR.sup.1 ; R represents H or a hydrocarbyl group of 1-10 carbon atoms; R.sup.1 represents a hydrocarbyl group of 1-10 carbon atoms, an acyl group of 1-10 carbon atoms; and when Y is NR.sup.1 the R and R.sup.1 can represent divalent groups so that together they form, with the N, a cyclic radical such as piperdyl, morpholino or diethylene diamino. Lithium alkoxides are preferred forms of the MYR formula and Al(CH.sub.3).sub.3 and Al(C.sub.2 H.sub.5).sub.3 are preferred aluminum components.
摘要:
A system for wetting fine dry powders such as bentonite clay with water or other liquids is described. The system includes a wetting tank for receiving water and a continuous flow of fine powder feed. The wetting tank has a generally square horizontal cross section with a bottom end closure in the shape of an inverted pyramid. Positioned centrally within the wetting tank is a flow control cylinder which is supported from the walls of the wetting tank by means of radially extending inclined baffles. A variable speed motor drives a first larger propeller positioned immediately below the flow control cylinder in a direction which forces liquid filling the tank to flow downward through the flow control cylinder and a second smaller propeller positioned below the larger propeller having a reverse pitch to oppose the flow of liquid being driven downward by the larger propeller.
摘要:
This invention relates to rubber compositions having a low aromatic-oil content, or no aromatic oils at all. The rubber composition contains a diene rubber, one or more fillers, and a low molecular weight, functionalized polymer than has the ability to interact with the fillers and act and as a replacement to the aromatic oil. The rubber compositions so produced may be used in tread rubbers and have exhibited good snow/wet traction properties and low rolling resistance.
摘要:
A method for forming a rubber-modified polymeric composition includes polymerizing vinyl aromatic monomer within a mixture including the vinyl aromatic monomer and an interpolymer having at least one block of polyisoprene, at lest one block of polystyrene, and at lest one block of polybutadiene to thereby form the rubber-modified polymeric composition, where the interpolymer includes an internal block of polyisoprene.
摘要:
Provided is a polymer nanoparticle comprising a core and a vulcanizable shell, wherein the core has a glass transition temperature (Tg) of at least about 150° C. Also provided is a method of preparing polymer nanoparticles with a core and a vulcanizable shell, comprising (a) in a liquid hydrocarbon medium, polymerizing conjugated diene monomers to produce a poly(conjugated diene) block and (b) copolymerizing the poly(conjugated diene) block with a mixture of mono-vinyl aromatic monomers and multiple-vinyl aromatic monomers to produce an aromatic block, wherein the core has a Tg of at least about 150° C. Also provided is a composition comprising (a) a rubber matrix; and (b) a polymer nanoparticle including a core and a vulcanizable shell; wherein the Tg of the core is at least about 150° C.
摘要:
Terminally functionalized polymers that are living or pseudo-living polymers reacted with certain allyl glycidyl ethers, or certain allylhalosilanes or combinations thereof, and a process for preparing the terminally functionalized polymers. Rubber-modified polymeric compositions comprising the terminally functionalized polymers.
摘要:
Thermoplastic elastomers containing hard segments formed from polyalkylenes and soft segments formed from elastomeric polymers near their gelation point are formed. Compositions containing these materials are elastomeric and exhibit excellent damping capabilities over a wide range of temperatures and frequencies.