Abstract: Centrifugal apparatus for the continuous separation of solids-liquid mixtures and the internal washing of separated solids is provided with one or more conduits to deliver washing liquid into centrifugally sedimented solids tumbling and suspending these solids in washing liquid. A distal end of each wash conduit is positioned in close proximity to the inner surface of the centrifuge bowl near the conveyor blade which is adapted to contact the solids upon separation and propel separated solids toward the solids discharge port. The invention includes centrifugal apparatus provided with plurality of cutting tools such as knife blades adapted to cut and separate the sedimented solids. In another aspect of the invention centrifugal apparatus is provided with one or more dip weirs dividing the centrifugally separated liquid pool in the bowl into axially adjacent zones with suitable a passageway for transfer of liquids and solids between adjacent zones.

Abstract: Polyimide optical waveguide structures comprising a core within a cladding wherein at least one of the core and the cladding is a polyimide containing 6FDA; and the complementary portion of the waveguide structure is a polyimide having partial replacement of the 6FDA of the core or cladding composition by BPDA, and wherein the difference in the birefringence of the core and cladding are less than the difference in the refractive index. Copolyimides containing 6FDA and BPDA moieties, and at least one diamine, which have properties useful in optical applications including adjustable refractive index and controllable birefringence, low optical losses, low optical absorbance, increased solvent resistance, and high thermal stability. A method for adjusting the refractive index to make useful copolyimide core/cladding waveguide structures by controlling the 6FDA/BPDA ratio.

Abstract: This invention relates to new and useful melt blend compositions of polyethylene terephthalate and polyethylene isophthalate, and melt blend compositions of polyethylene terephthalate with random copolymers of polyethylene terephthalate and polyethylene isophthalate wherein each polyester contains an interesterification inhibitor, wherein the resulting melt blend composition of polyesters retain the predominant characteristics of the predominant polyester by weight of the melt blend composition. The extruded polymer melt blend compositions have utility as shrink fiber and film, and as adhesives in the form of powdered binders for non-woven fabrics.

Abstract: A process for preparing purified 2,6-naphthalenedicarboxylic acid which comprises hydrolyzing a dialkyl-2,6-naphthalenedicarboxylate with water at a reaction temperature of at least about 450.degree. F. under liquid phase condition, the amount of water present being sufficient to solubilize, at the reaction temperature, at least about 10 percent of the 2,6-naphthalenedicarboxylic acid formed; and a process for purifying 2,6-naphthalenedicarboxylic acid comprising combining impure 2,6-naphthalenedicarboxylic acid with a purification solvent, heating the resulting mixture under liquid phase conditions at a temperature of at least about 500.degree. F. to form a product mixture and thereafter recovering from the product mixture purified 2,6-naphthalenedicarboxylic acid.

Abstract: This invention relates to a process for preparation of non-crosslinked linear monofunctional and telechelic difunctional unsaturated polymers wherein the functional groups are acrylate or methacrylate groups. The average functionality number of the monofunctional unsaturated polymers is at least 0.7, as determined by nuclear magnetic resonance spectroscopy (NMR). The average functionality number of the telechelic difunctional polymers is at least 1.7, as determined by NMR. Alkyl acrylates or alkyl methacrylates are reacted with cyclic olefinic non-conjugated compounds or unsaturated hydrocarbon polymers to prepare monofunctional and difunctional polymers. The process is substantially free of side reactions comprising double bond migration and cyclization.

Abstract: Processes using a titanium dioxide-supported purification catalyst are disclosed for purification of relatively impure dicarboxylic aromatic acid produced by liquid-phase oxidation of a suitable benzene or naphthalene having two oxidizable ring substituents, and/or by recovery from polyester resin comprising repeating units of the dicarboxylic aromatic acid residue and repeating units of dihydric alcohol residue. Purification comprises passing an aqueous solution of dicarboxylic aromatic acid with small amounts of organic impurities consisting of oxygen-containing aromatic co-products of oxidation and/or other organic components, through a particulate bed of purification catalyst comprising a noble metal on a titanium dioxide support under conditions suitable for decarbonylation of organic impurities. Generally, at least one weight percent of the titanium dioxide support is in the ruffle crystalline phase.

Abstract: An apparatus useful for preparing aromatic carboxylic acids by the exothermic liquid-phase oxidation reaction of an aromatic feedstock compound is disclosed, wherein energy is efficiently recovered from the exothermic oxidation reaction.

Abstract: Dual-flow chemical reactor cores containing catalytic heat-transfer walls comprising both a gas-impervious material and a suitable catalyst which allows oxidative coupling of methane into higher hydrocarbons, dual-flow reactors having these catalytic heat-transfer walls to control and facilitate simultaneously coupling of methane and cracking of hydrocarbon compounds in separate gas streams, and chemical processes which combine coupling of methane and cracking of hydrocarbon compounds to make olefins in a dual-flow reactor having catalytic heat-transfer walls.

Abstract: A photoimageable polyimide coating which can be prepared from the polymeric condensation product of 6FDA, DMDE or MEDA, and a photosensitizing moiety. More particularly, the present invention relates to a photoimageable polyimide coating useful for microelectronic applications.

Abstract: A hydrophobic polyurethane elastomer composition is disclosed containing a linear soft segment without pendant chain branched groups, wherein said polyurethane elastomer has a glass transition temperature (Tg) of less than -70.degree. C. and a moisture uptake of less than 1.0 wt. % after 24 hours of immersion in water at 70.degree. C., and wherein said polyurethane elastomer comprises at least one repeat unit containing said linear soft segment, which soft segment comprises a moiety derived from a polyol of the structure:X--[CH.dbd.CH(CH.sub.2).sub.n ].sub.m CH.dbd.CH--Xwherein X is a hydroxyl-containing moiety selected from the group consisting of --CH.sub.2 OH, --(CH.sub.2).sub.8 COO(CH.sub.2).sub.p OH and --COO(CH.sub.2).sub.p OH, wherein the functionality number of the terminal groups is 2.0, p is 2 to 12, n is 1 to 10, m is a number average value of up to 1000, and the weight of the polyol is from about 0.5 wt. % to about 99.5 wt. % of the resulting polyurethane elastomer.

Abstract: This invention relates to difunctional telechelic linear non-crosslinked polyolefins without pendant chain branched groups. The polyolefin compounds of this invention are useful for preparing high molecular weight polyesters, polyamides, polyureas and polyurethanes of high density without branching of the polymer chains, and with low permeability to gases and solvents.

Abstract: A process for preparing purified 2,6-naphthalenedicarboxylic acid which comprises hydrolyzing a dialkyl-2,6-naphthalenedicarboxylate with water at a reaction temperature of at least about 450.degree. F. under liquid phase condition, the amount of water present being sufficient to solubilize, at the reaction temperature, at least about 10 percent of the 2,6-naphthalenedicarboxylic acid formed; and a process for purifying 2,6-naphthalenedicarboxylic acid comprising combining impure 2,6-naphthalenedicarboxylic acid with a purification solvent, heating the resulting mixture under liquid phase conditions at a temperature of at least about 500.degree. F. to form a product mixture and thereafter recovering from the product mixture purified 2,6-naphthalenedicarboxylic acid.

Abstract: This invention relates to difunctional telechelic linear non-crosslinked polyolefins without pendant chain branched groups. The polyolefin compounds of this invention are useful for preparing high molecular weight polyesters, polyamides, polyureas and polyurethanes of high density without branching of the polymer chains, and with low permeability to gases and solvents.

Abstract: A photoimageable polyimide coating which can be prepared from the polymeric condensation product of 6FDA, DMDE or MEDA, and a photosensitizing moiety. More particularly, the present invention relates to a photoimageable polyimide coating useful for microelectronic applications.

Abstract: This invention relates to a peroxide process for preparation of controlled rheology polypropylene resins wherein 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane is the peroxide and the melt flow rate is increased by the presence of a thioester of the general formula ##STR1## wherein n is a whole number of from 6 to 16.

Abstract: Hot-melt adhesives based upon a mixture composed of poly(vinylmethylether), greater than about 10 weight percent of a thermoplastic resin and, optionally a tackifier resin and/or extender, are found to be superior for the binding of polyolefins such as polyethylene, polypropylene, and ethylene-propylene copolymers to themselves and to other substrates. In particular, the hot-melt adhesives are useful for bonding polyethylene-backed and latex-backed carpet to polyethylene, polypropylene, or ethylene-propylene copolymer.

Abstract: A polymerization process for preparation of oligomers and polymers having at least one internal carbon-to-carbon double bond and containing functional groups comprising terminal carbon-to-carbon double bonds is disclosed. The polymerization process is substantially free of side reactions comprising double bond migration. The oligomers and polymers are prepared from acyclic polyenes of from 2 to about 30 carbon atoms. The catalyst system comprises a metathesis catalyst (A) comprising a transition metal compound, an activator (B) selected from the group consisting of organic tin compounds and organic aluminum halides and (C) an organic Lewis base. Yields are at least 60% of theoretical based on acyclic polyene reactant.

Abstract: This invention relates to a process for preparation of non-crosslinked linear monofunctional and telechelic difunctional unsaturated polymers wherein the functional groups are reactive terminal groups other than vinyl groups. The average functionality number of the monofunctional unsaturated polymers is at least 0.7, as determined by nuclear magnetic resonance spectroscopy (NMR). The average functionality number of the telechelic difunctional polymers is at least 1.7, as determined by NMR. Monofunctional olefins and difunctional olefins are reacted with cyclic olefins or unsaturated polymers to prepare difunctional polymers. The process is substantially free of side reactions comprising double bond migration and cyclization.

Abstract: A method for recovering crystalline 2,6-dimethylnaphthalene comprising crystallizing in a scraped-wall crystallizer apparatus at crystallization temperature T, a mixture of low melting components, LM, having melting points of 70.degree. F. and below, and high melting components (HM), including 2,6-dimethylnaphthalene, having melting points above 70.degree. F., such that: ##EQU1## where HM is the total weight percent of high melting components, including 2,6-dimethylnaphthalene, in the mixture, and LM is the total weight percent of low melting components in the mixture, and where T is the temperature of the crystallization in degrees Fahrenheit, and where A is at least 1.0.

Abstract: A thixotropic gel composition is disclosed as a fiber optic buffer tube compound. The composition as a fiber optic buffer tube compound is resistant to syneresis and phase separation, and to ingress of water and water vapor. The composition has low temperature flowability at -40.degree. C. as determined by a cone penetration test and has continued high temperature consistency at +80.degree. C. The composition retains its low temperature flowability property after a heat aging test at 93.degree. C. The composition comprises polybutene, polyethylene wax, hydrophobic fumed silica, and, optionally, an antioxidant.