Abstract:
Ethylene is homopolymerized in the presence of a catalyst consisting essentially of a Group 3 metal complex, preferably a scandium complex, having a bridged ligand structure. Optionally polymer blends are prepared by combining the process with another polymerization process, either in series or in parallel.
Abstract:
A process is described for the recovery of hydrogen chloride in anhydrous form (42) from a dry mixture of one or more non-condensable gases, hydrogen chloride and heavier components which may be present (16), which process comprises using a halogenated hydrocarbon solvent (22), and especially a chlorinated hydrocarbon solvent, to preferentially absorb hydrogen chloride and heavier materials from the dry mixture, with the non-condensable gases contained in the mixture being carried through as a gas stream (38) and the rich solvent stream (36) being processed to separate out and recover the hydrogen chloride therein in anhydrous form.
Abstract:
Seeded cation-exchange resin beads are particularly susceptible to oxidative degradation which results in the leaching of organic carbon fragments. The leachability of organic carbon fragments of molecular weights greater than 1000 g/mol is reduced to less than 800 ppm by effectively crosslinking the copolymers that comprise the seeded cation-exchange resin beads. Crosslinking can be achieved either during sulfonation by increasing sulfone bridge formation or before sulfonation by either alkylene bridge formation or by incorporation and subsequent activation of a crosslinkable functionality in the copolymer that forms the seed in the seeded polymer bead process.
Abstract:
Disclosed is a process for preparing a rigid, hydrocarbon-blown, polyurethane foam by reacting a polyisocyanate with a polyurethane precursor composition comprising a polyol and a compatibilizing agent containing a compatibilizing radical of the formula: -(CnH2n+1) wherein n is a number greater than or equal to 5, and wherein the compatibilizing agent contains at least one active hydrogen atom, provided that there is no more than one aromatic group per molecule, and further wherein the compatibilizing agent is a fat, oil, monoglyceride, diglyceride, fatty acid, fatty alcohol, fatty amide, fatty amine, fatty acid ester, alkoxylated adduct of any of the foregoing, alkyl phenol or propoxylated adduct thereof, alkyl phenol or adduct thereof with ethylene oxide and propylene oxide, alkyl phenol or adduct thereof with less than an average of four molecules of ethylene oxide per molecule of alkyl phenol or a mixture thereof. A preferred compatibilizing agent is castor oil. The compatibilizing agent enhances the miscibility of the hydrocarbon blowing agent. Advantageously, the polyurethane precursor compositions exhibit improved storage stability.
Abstract:
Addition polymers of ethylenically unsaturated monomers are provided comprising a 5-, 6- or 7-membered polymer unit formed from a copolymerizable, unsaturated, chain transfer agent containing a labile hydrogen and capable of forming by means of a hydrogen shift mechanism a free radical having 5, 6 or 7 atoms between and including the alpha -carbon of the ethylenically unsaturated group and the labile hydrogen.
Abstract:
Disclosed is a process for preparing a low density closed-cell polymer foam comprising a plurality of closed-cells having an average cell size of at least about 0.08 millimeter characterized in that the process comprises the steps of heat plastifying an expandable or foamable monovinyl aromatic polymer formulation comprising a non-linear monovinyl aromatic polymer composition and an environmentally acceptable blowing agent; and reducing the pressure on the mixture to form a foam. A stable monovinyl aromatic polymer foam prepared from a non-linear styrenic polymer composition and environmentally acceptable blowing agents is also disclosed.
Abstract:
Monovinyl aromatic polymer compositions with high melt strength, good flow and good heat properties which are suitable for fast injection molding, blow molding and thermoforming applications, comprising non-linear monovinyl aromatic polymers and copolymers having comb-type structures with 3 branches, star type structures with 4 to 6 branches, and/or dendritic structures in which the branches themselves have attached branched units. These compositions possess inherent melt strength and can be blow molded or thermoformed without sagging or molded into articles in shorter cycle times using less material than linear monovinyl aromatic polymers and copolymers with the same flow and heat distortion temperatures. Also dislosed is a process for making high molecular weight branched monovinyl aromatic polymers, for example, Mw between 75,000 and 500,000, at high rates, comprising polymerizing pure styrene monomer or styrene monomer and polymerizable comonomer via a continuous free radial polymerization process using a peroxide initiator, for example, n-butyl tert-butyl peroxy fumarate, selected from a new class of vinyl peroxide initiators that contain both a copolymerizable double bond and an organic peroxide moiety.
Abstract:
An extended Harvard architecture memory system which features an address store for containing an ordered sequence of program memory addresses, and a value store for containing a series of related data value sets. Each of the addresses contained in the address store is associated with a distinct set of instructions, such as a subroutine, that is contained in the program memory. The address store may also contain the address of one or more instruction arguments that are, in turn, contained in the value store or in a separate data memory. Both the address store and the value store are preferably connected to the same data communication path which is used by the data memory of the computer. The value store also includes a logic interface for enabling a plurality of different address increments to be programmably selected.
Abstract:
The subject invention provides a thermoset elastomer comprising a crosslinked pseudorandom or substantially random interpolymer of: (a) from 15 to 70 weight percent of at least one alpha -olefin, (b) from 30 to 70 weight percent of at least one vinylidene aromatic compound, and (c) from 0 to 15 weight percent of at least one diene. The subject invention further provides provides a thermoplastic vulcanizate comprising the thermoset elastomers of the invention as provided in a thermoplastic polyolefin matrix. The subject invention further provides processes for preparing the inventive thermoset elastomers and thermoplastic vulcanizates, as well as parts fabricated therefrom. The inventive materials have a superior balance of properties, as compared to EPM and EPDM based materials.
Abstract:
Filled blends of (A) carbonate polymers and (B) monovinylidene aromatic copolymers are prepared having improved combinations of resistance to linear thermal expansion and low temperature toughness. A wax additive (C) is employed which improves the low temperature toughness of the filled polymer blend. The wax additive is preferably ester wax, acid wax, polyethylene wax, or a blend of two or more of these waxes, with ester wax being the preferred wax. Preferably, specifically shaped, small particle size fillers (D) are employed which provide the resistance to linear thermal expansion and maintain the impact resistance of the filled blend. Optionally, the blend also comprises a rubber impact modifier (E) to provide improved toughness in molded articles prepared from the filled blend. These components are employed generally in amounts of from 50 to 95 percent by weight (A) and from 5 to 50 percent by weight (B) based on weight of components (A), (B) and (E); from 0.1 to 5 percent by weight (C) and from 1 to 17 percent by weight (D) based on weight of components (A, B, C, D and E); and optionally from 1 to 20 percent by weight (E) based on weight of components (A), (B) and (E).