Abstract: A urethane polymer having free acidic groups on the backbone of the polymer and terminal (meth)acrylate groups is prepared by (1) reacting a mixture comprising an aliphatic diol and a diol having acidic functionality with an excess of an aliphatic, cycloaliphatic or aromatic diisocyanate in the presence of a catalyst to produce an isocyanate-terminated urethane polymer and (2) reacting the terminal isocyanate groups of the product of step (1) with a mono- or dihydroxy (meth)acrylate. The diol comprises greater than 50% of the reaction mixture, based on the total weight of reactants. The polymer can be used in photopolymerizable compositions for making low tack flexographic printing plates and photopolymer masters.

Abstract: Disclosed are organosilicon crosslinked polymers and crosslinkable prepolymers that are the reaction product of (a) a cyclic polysiloxane in which each silicon atom is substituted with (i) a saturated, substituted or unsubstituted alkyl or alkoxy group or a substituted or unsubstituded aryl or aryloxy group, and (ii) a substituted or unsubstituted hydrocarbon group having at least one carbon-carbon double bond that is reactive in hydrosilation, (b) at least one organosilicon compound having at least two .tbd.SiH groups, and optionally (c) a hydrocarbon polyene having at least two nonaromatic carbon-carbon double bonds that are reactive in hydrosilation. A process for preparing the polymers and prepolymers and for preparing the cyclic polysiloxanes is also disclosed.

Abstract: This invention relates to a two component catalyst system for the polymerization of metathesis polymerizable cycloolefins, comprising (a) a tungsten compound of the formula WOX.sub.4-x (OAr).sub.x where X is chlorine, bromine or fluorine, Ar is a hindered phenyl ring having 1-5 specified substituents and x = 1, 2 or 3; and (b) an activator compound.Among the preferred molecules or groups that are substituted on the phenyl ring of the tungsten compound are phenyl, chlorine, bromine, methoxy and isopropyl groups. Ar can also represent a multi-substituted phenyl group such as 2,4-dichloro-6-methylphenyl.

Abstract: Impurities such as oxygen and moisture can be removed from sulfur hexafluoride by contacting the impure gas with the reaction product of sulfur hexafluoride and a lithium-substituted macroreticulate polymer.

Abstract: This invention relates to a two component catalyst system for polymerization of metathesis polymerizable cycloolefins, comprising(a) a tungsten compound of the formula WOX.sub.4-x (OAr).sub.x wherein x represents chlorine, bromine or fluorine, Ar represents a hindered phenyl ring having 1-5 substituents and x=1, 2, or 3; and(b) an activator compound.Among the preferred molecules or groups that are substituted on the phenyl ring of the tungsten compound are chlorine, bromine, phenyl, methoxy and isopropyl groups. Ar can also represent a multisubstituted phenyl group such as 2,4-dichloro-6-methylphenyl.

Abstract: Aluminum-nitrogen polymers comprising a backbone of alternating aluminum and nitrogen atoms both having pendant organic groups, wherein some of the pendant organic groups are unsaturated, are prepared by reacting an unsaturated organic nitrile with a dialkylaluminum hydride. The polymers are crosslinked by supplying energy to generate free radicals. The crosslinked polymers can be pyrolyzed to form an aluminum nitride ceramic.

Abstract: Impurities such as oxygen and moisture can be removed from sulfur hexafluoride by contacting the impure gas with the reaction product of sulfur hexafluoride and a lithium-substituted macroreticulate polymer.

Abstract: A block copolymer is prepared by reacting an aluminum-nitrogen polymer and a silazane polymer at a temperature not greater than 400.degree. C. Block copolymers containing alkenyl or alkynyl groups can be crosslinked by supplying energy to generate free radicals. An AlN/SiC containing ceramic is formed by pyrolyzing the crosslinked block copolymer in a nonoxidizing atmosphere.

Abstract: Disclosed is a UV-curable, aqueous developable liquid solder mask composition comprising (1) 40%-70% of a nonreactive binder that is a film-forming random copolymer of (a) one or more (meth)acrylic alkyl ester monomers, at least one of which is an ester of a 4-12 carbon alkanol, (b) acrylic or methacrylic acid, and optionally (c) styrene or .alpha.-methylstyrene, (2) 20%-40% of one or more (meth)acrylic ester monomers containing two or more ethylenic double bonds, wherein at least one of the monomers has at least four ethylenic double bonds, (3) 1%-5% of a free radical-generating photoinitiator, (4) 5%-15% of a filler, all percentages being by weight based on the nonsolvent components of the composition, and (5) an organic solvent.

Abstract: A Grignard reagent having the formula RMgX where R is a cycloalkyl or cycloalkenyl group and X is Cl, Br or I, is used as the catalyst activator for the metathesis polymerization of dicyclopentadiene and other polycyclic cycloolefins.

Abstract: A sintered silicon carbide product having improved fracture toughness contains from 1% to 80% by weight of (a) a uniformly dispersed, nonagglomerated, high metal content silicide of iron, nickel, cobalt or molybdenum in which the metal/silicon ratio is equal to or greater than 1. The silicon carbide starting material can be alpha-phase, beta-phase or a mixture of the two.

Abstract: This invention relates to a two component catalyst system for the polymerization of metathesis polymerizable cycloolefins, comprising(a) a pure tungsten-imido compound (procatalyst) of the formulaW(NR.sup.1)X.sub.4-x (OR.sup.2).sub.x.L.sub.ywherein x=0, 1, 2, 3 or 4; y=0 or 1; R.sup.1 and R.sup.2 are alkyl, phenyl, phenyl-substituted phenyl, phenylalkyl or halogen substituted derivatives of alkyl, phenyl, phenyl-substituted phenyl or phenylalkyl; X=Br or Cl; where alkyl has 1 to 8 carbon atoms, phenyl-substituted phenyl has 12-18 carbon atoms and phenylalkyl has 7 to 20 carbon atoms; L is a donor ligand; and(b) an activator compound selected from organometals and organometal hydrides with tri-n-butyltin hydride and tri-octyltin hydride the most preferred.

Abstract: A process for reaction injection molding of ceramic articles is disclosed. The process comprises (a) injecting a fluid, non-dilatant mixture comprising a ceramic powder, a metal powder or mixtures thereof, and a curable ceramic precursor that is a liquid below its curing temperature, into a heated mold, (b) curing the ceramic precursor to produce a hardened molded article, (c) heating the hardened molded article under a suitable atmosphere to a temperature sufficient to convert the ceramic precursor to a ceramic, and (d) sintering the ceramic to the desired density.

Abstract: One or more layers of a sheet comprising (1) 60% to 99%, based on the weight of solids, of vermiculite delaminated by mechanical means only, (2) 1% to 40%, based on the weight of solids, of at least one fibrous material and (3) 0.1% to 4%, based on the weight of the vermiculite, of at least one flocculating agent, can be used to protect heat-sensitive substrates such as resin matrix composites from fire or heat.

Abstract: A tackifier resin is prepared by polymerizing a monomer mixture of 10-70% piperylene concentrate and 30-90% of a vinyl aromatic monomer in the presence of a boron trifluoride catalyst and an inert diluent. The resin is water white in color, has a Gardner number of less than one, a softening point of 60.degree. to 120.degree. C. and a polydispersity of 1 to 5. The tackifier is used in formulations based on EVA, block copolymers and polyolefins for hot melt and pressure sensitive adhesive applications.

Abstract: A composition that comprises a (thio)amide-modified silazane polymer containing at least one alkenyl or alkynyl group and a free radical generator can be crosslinked by an energy input provided in the form of heat, ultraviolet radiation, or an electron beam. The crosslinked (thio)amide-modified silazane polymer composition can be pyrolyzed to form a silicon nitride-containing ceramic.

Abstract: Disclosed is a process for making a composite sheet using papermaking techniques. The composite sheet comprises (1) 20% to 99%, based on the weight of solids, of vermiculite delaminated by mechanical shearing only, (2) 1% to 80%, based on the weight of solids, of at least one fibrous material and (3) 0.1% to 10%, based on the weight of the vermiculite, of at least one flocculating agent.

Abstract: An aqueous dispersion of vermiculite lamellae is provided having incorporated therein from about 0.2 to about 10% by weight of at least one internal sizing agent based on the dry weight of the vermiculite in the dispersion.

Abstract: The color and color stability of tall oil fractions are improved and the odor and sulfur content are reduced by treating the heated black liquor soap skimmings prior to acidulation with 1.0 to 1.5 wt. % hydrogen peroxide for at least one minute.

Abstract: A metathesis catalyst activator composition consisting essentially of an alkoxyalkylaluminum halide and a tin compound in a molar ratio of about 0.15 to 2 moles of the alkoxyalkylaluminum halide per mole of tin compound.