3517 results about "Crosslinked polymers" patented technology

A medical implant of ultrahigh molecular weight polyethylene having an improved balance of wear properties and oxidation resistance is prepared by irradiating a preform of ultrahigh molecular weight polyethylene, annealing the irradiated preform in the absence of oxygen to a temperature at or above the onset of melting temperature, and forming an implant from the stabilized cross-linked polymer. Implants prepared according to the process of the present invention have comparable oxidation resistance and superior wear performance compared to unirradiated ultrahigh molecular weight polyethylene.

The invention relates to absorptive, crosslinked polymers which are based on partly neutralized, monoethylenically unsaturated monomers carrying acid groups wherein the absorptive crosslinked polymer may be coated with a thermoplastic polymer, and have improved properties, in particular in respect of their capacity for transportation of liquids in the swollen state, and which has a high gel bed permeability and high centrifuge retention capacity.

An implantable prosthetic bearing is constructed of a composite material having a first layer and second layer. The first layer has an articulating surface defined therein, whereas the second layer has a engaging surface defined therein for engaging either another prosthetic component or the bone itself The first layer of the implantable prosthetic bearing is constructed of crosslinked polymer such as Ultra-High Molecular Weight Polyethylene, whereas the second layer of the implantable prosthetic bearing is constructed of polymer such as Ultra-High Molecular Weight Polyethylene that is either non-crosslinked or crosslinked to a lesser degree than the first layer. In such a manner, the first layer possesses mechanical properties which are advantageous in regard to the articulating surface (e.g., enhanced wear and oxidation resistance), whereas the second layer possesses mechanical properties which are advantageous in regard to the engaging surface (e.g., high ductility, toughness, and creep resistance). A method of making a prosthetic bearing is also disclosed.

A method for minimizing the amount of metal crosslinked viscosifier necessary for treating a wellbore with proppant or gravel is given. The method includes using fibers to aid in transporting, suspending and placing proppant or gravel in viscous carrier fluids otherwise having insufficient viscosity to prevent particulate settling. Fibers are given that have properties optimized for proppant transport but degrade after the treatment into degradation products that do not precipitate in the presence of ions in the water such as calcium and magnesium. Crosslinked polymer carrier fluids are identified that are not damaged by contaminants present in the fibers or by degradation products released by premature degradation of the fibers.

Provided is an anode for use in electrochemical cells, wherein the anode active layer has a first layer comprising lithium metal and a multi-layer structure comprising single ion conducting layers and crosslinked polymer layers in contact with the first layer comprising lithium metal or in contact with an intermediate protective layer, such as a temporary protective metal layer, on the surface of the lithium-containing first layer. The anodes of the current invention are particularly useful in electrochemical cells comprising sulfur-containing cathode active materials, such as elemental sulfur.

A process for the crosslinking of at least one polymer selected from polysaccharides and derivatives thereof, which is carried out in an aqueous solvent by the action of an effective and non-excessive amount of at least one crosslinking agent, characterized in that it is carried out on a mixture containing at least one low-molecular weight polymer and at least one high-molecular weight polymer. A process for the preparation of an injectable monophase hydrogel of at least one crosslinked polymer selected from polysaccharides and derivatives thereof. Crosslinked polymers and injectable monophase hydrogels respectively obtainable by each of said processes.

Embodiments of the present invention include a material comprising a polymer having a modulus of elasticity less than 105 Pa and a material comprising a polymer having a modulus of elasticity of less than 5×104 Pa. Embodiments also include a material comprising a polymeric network and a multiplicity of side chains attached to the polymeric network. The multiplicity of side chains may have an average molecular weight below the critical molecular weight for entanglements. In certain embodiments it may be advantageous for the side branches to have a glass transition temperature below the use temperature of the material. The polymer network may comprise at least two monomers so that the polymer network is a copolymer. Embodiments of the present invention also include methods of forming a polymer network. Such as, for example, a method of preparing a polymer network comprising cross-linking a polymer, wherein the polymer comprises a multiplicity of side chains. The polymer may be at least one of a polymer brush, a polymer comb, and a nanocomposite material. An additional embodiment may include polymerizing macromonomers in the presence of a crosslinking agent. This embodiment may result in the forming a polymer network, wherein the polymer network comprises a multiplicity of branches attached to the polymer network, wherein the macromonomers may have a molecular weight less than the critical molecular weight for entanglements. Another embodiment of the method of forming a polymer network may comprising polymerizing monomers directly from a crosslinked polymer network. This method may result in forming a branched polymer network, wherein the polymer network comprises a multiplicity of branches attached to the polymer network.