1188results about How to "Reduce molecular weight" patented technology

Composite particles made of a binder and filler material are provided for use in subterranean formations. The filler is finely divided mineral and optional fiber. The particles are proppants useful to prop open subterranean formation fractures. The particles are also useful for water filtration and artificial turf for sports fields. Methods of making the composite particles are also disclosed.</PTEXT>

An acid fracturing method is provided in which the acid is generated in the fracture by hydrolysis of a solid acid-precursor selected from one or more than one of lactide, glycolide, polylactic acid, polyglycolic acid, a copolymer of polylactic acid and polyglycolic acid, a copolymer of glycolic acid with other hydroxy-, carboxylic acid-, or hydroxycarboxylic acid-containing moieties, and a copolymer of lactic acid with other hydroxy-, carboxylic acid or hydroxycarboxylic acid-containing moieties. The solid acid-precursor may be mixed with a solid acid-reactive material to accelerate the hydrolysis and/or coated to slow the hydrolysis. Water-soluble liquid compounds are also given that accelerate the hydrolysis. The method ensures that the acid contacts fracture faces far from the wellbore.

Abstract of the Disclosure A gapfill process is provided using cycling of HDP-CVD deposition, etching, and deposition step. The fluent gas during the first deposition step includes an inert gas such as He, but includes H2 during the remainder deposition step. The higher average molecular weight of the fluent gas during the first deposition step provides some cusping over structures that define the gap to protect them during the etching step. The lower average molecular weight of the fluent gas during the remainder deposition step has reduced sputtering characteristics and is effective at filling the remainder of the gap.

A composite osteoimplant. The osteoimplant includes a polymer and bone-derived particles. The composite is adapted and constructed to be formable during or immediately prior to implantation and to be set after final surgical placement.

A sulfonium salt having a polymerizable anion generates a strong sulfonic acid upon exposure to high-energy radiation so that it facilitates effective scission of acid labile groups in chemically amplified resist compositions. It is useful as a monomer from which a base resin for use in radiation-sensitive resist compositions is derived.

Disclosed are methods useful for treating vascular lesions wherein a non-particulate agent such as a metal coil is introduced into a vascular site (e.g., an aneurysm cavity) in conjunction with an embolizing composition comprising a biocompatible polymer and a biocompatible solvent. The biocompatible solvent is miscible or soluble in blood and also solubilizes the polymer during delivery. The biocompatible polymer is selected to be soluble in the biocompatible solvent but insoluble in blood. Upon contact with the blood, the biocompatible solvent dissipates from the embolic composition whereupon the biocompatible polymer precipitates. Precipitation of the polymer in the presence of the non-particulate agent permits the agent to act as a structural lattice for the growing polymer precipitate. In another embodiment, the biocompatible polymer composition can be replaced with a biocompatible prepolymer composition containing a biocompatible prepolymer.

New ligands, compositions, metal-ligand complexes and arrays with pyridylamine ligands are disclosed that catalyze the polymerization of monomers into polymers. Certain of these catalysts with hafnium metal centers have high performance characteristics, including higher comonomer incorporation into ethylene/olefin copolymers, where such olefins are for example, 1-octene, isobutylene or styrene. Certain of the catalysts are particularly effective at polymerizing propylene to high molecular weight isotactic polypropylene in a solution process at a variety of polymerization conditions.

This invention relates to novel compositions comprising regioselectively substituted cellulose esters. One aspect of the invention relates to processes for preparing regioselectively substituted cellulose esters from cellulose dissolved in ionic liquids. Another aspect of the invention relates to the utility of regioselectively substituted cellulose esters in applications such as protective and compensation films for liquid crystalline displays.

Polymer and drug containing compositions and method of preparing such compositions are disclosed. The dispersed phase formulation has a polymer, a pharmaceutically or biologically active agent and a small fraction of low pKa acid additive. Stable, filter sterilizable, non-gelling solutions containing GnRH analogues at least at levels typically used in sustained release formulations and a method of increasing solubility of a high level of a GnRH analogue or a freeze-dried antgonist of GnRH in a polymer containing solution are also disclosed. The amount of the acid additive in the polymer solution is such that it is sufficient to increase the solubility of the high level of the GnRH analogue in the polymer solution without affecting the release characteristics of the microspheres prepared therefrom.

A method for utilizing whole crude oil as a feedstock for the pyrolysis furnace of an olefin production plant wherein the feedstock after preheating is subjected to mild cracking conditions until substantially vaporized, the vapors from mild cracking being subjected to severe cracking in the radiant section of the furnace.

A method for enhancing foam stability in foaming compositions for use in oilfield treatment application, including but not limited to use in mobility control for gas flooding. The method comprises the step of adding to a foaming composition a foam stabilizer of formula (I):

wherein R₁ is an alkylamido group or a branched or linear alkyl group; R₂ and R₃ are individually hydrogen or a methyl group; R₄, R₅ and R₆ are individually hydrogen or a hydroxy group, with the proviso that at least one of R₄, R₅ or R₆ is a hydroxyl group; wherein the alkyl group has greater than about 10 carbon atoms. Also disclosed are methods to enhance foam stability in an aqueous foaming composition.

Sulfonate salts have the formula: CF₃—CH(OCOR)—CF₂SO₃⁻M⁺ wherein R is C₁-C₂₀ alkyl or C₆-C₁₄ aryl, and M⁺ is a lithium, sodium, potassium, ammonium or tetramethylammonium ion. Onium salts, oximesulfonates and sulfonyloxyimides and other compounds derived from these sulfonate salts are effective photoacid generators in chemically amplified resist compositions.

A composition for delivering an active agent to a patient. The composition includes a polymer core encapsulating the active agent and a mucoadhesive coating disposed about the core. The polymer may include covalently linked poly(ethylene glycol) chains, and the mucoadhesive coating may be selected to facilitate transfer of the particle through the intestinal mucosa. A molecular weight and cross-link density of the polymer may be selected such that the polymer core will decompose in a predetermined time interval. The fraction of the dose of the drug entering the system at circulation during the predetermined time interval may be between about 0.25% and about 25%. The composition may be formulated as a plurality of nanoparticles or microparticles that are combined with a pharmaceutically acceptable carrier to produce an edible or inhalable drug product.

High radiopacity is achieved in a polymeric marker by combining a polymeric resin, a powdered radiopaque agent having uniformly shaped particles of a specific particle size distribution, and a wetting agent. The method to produce the marker calls for the blending and pelletization of these materials followed by extrusion onto support beading. The resulting supported tubing is subsequently cut to length with the beading still in place. After ejection of the beading remnant the marker is slipped into place on the device to be marked and attached by melt bonding. Marking of a guide wire allows lesions to be measured while the marking of balloon catheters allow the balloon to be properly positioned relative to a lesion.

Novel catalyst systems for metathesis reactions, in particular for the metathesis of nitrile rubber, which contain a specific salt additive in addition to the metathesis catalyst are provided.