摘要:
In one or more embodiments, the present invention provides a novel approach to the addition of plasticizers for softening TPUs, i.e., lowering the durometer and the melt viscosity. This approach involves incorporating bonded sulfonate groups with quaternary ammonium counterions into the TPU. In one or more embodiments of the present invention, the softening of TPU is achieved by incorporating an ionic diol, such as N,N-bis (2-hydoxyethyl)-2-aminoethane-sulfonic acid (BES), coupled with various bulky alkyl ammonium cations, during the chain extension step of the TPU synthesis. It is believed that that steric hindrance of the bulky quaternary ammonium groups weakens the dipole-dipole interactions of the sulfonate groups and/or lowers the crystallinity of the hard block, thereby creating additional free volume that softens the polymer and lowers the melt viscosity.
摘要:
In one or more embodiments, the present invention provides a novel approach to the addition of plasticizers for softening TPUs, i.e., lowering the durometer and the melt viscosity. This approach involves incorporating bonded sulfonate groups with quaternary ammonium counterions into the TPU. In one or more embodiments of the present invention, the softening of TPU is achieved by incorporating an ionic diol, such as N,N-bis (2-hydoxyethyl)-2-aminoethane-sulfonic acid (BES), coupled with various bulky alkyl ammonium cations, during the chain extension step of the TPU synthesis. It is believed that that steric hindrance of the bulky quaternary ammonium groups weakens the dipole-dipole interactions of the sulfonate groups and/or lowers the crystallinity of the hard block, thereby creating additional free volume that softens the polymer and lowers the melt viscosity.
摘要:
The present invention is directed to a covalently crosslinked hydrogel comprising the strain-promoted reaction product of an 8-member cycloalkyne functionalized polyalkylene glycol and a multi-arm glycerol exytholate triazide and methods for making them. Because the precursor materials can be manipulated without causing crosslinking, provided the strain threshold is not reached, these hydrogels permit mechanical control over when (and where) cross linking occurs and are easier to use than prior strain-activated or temperature-activated systems. These novel hydrogels do not require a catalyst to cross link, thus avoiding the biocompatibility problems common to many catalysts. Nor is the crosslinking process affected by the presence of catalysts or other substances, which have interfered with crosslinking in known strain induced hydrogels. Because of their crosslinking reaction kinetics, these novel hydrogels can encapsulate and transport highly sensitive cells and other biological additives and have no known toxic byproducts.
摘要:
The present invention is directed to a covalently crosslinked hydrogel comprising the strain-promoted reaction product of an 8-member cycloalkyne functionalized polyalkylene glycol and a multi-arm glycerol exytholate triazide and methods for making them. Because the precursor materials can be manipulated without causing crosslinking, provided the strain threshold is not reached, these hydrogels permit mechanical control over when (and where) cross linking occurs and are easier to use than prior strain-activated or temperature-activated systems. These novel hydrogels do not require a catalyst to cross link, thus avoiding the biocompatibility problems common to many catalysts. Nor is the crosslinking process affected by the presence of catalysts or other substances, which have interfered with crosslinking in known strain induced hydrogels. Because of their crosslinking reaction kinetics, these novel hydrogels can encapsulate and transport highly sensitive cells and other biological additives and have no known toxic byproducts.
摘要:
This invention is an improved method and device for treating varicose veins 200 or the greater saphenous vein 202. The method comprises the use of infrared laser radiation in the region of 1.2 to 2.2 um in a manner from inside the vessel 200 or 202 such that the endothelial cells of the vessel wall 704 are damaged and collagen fibers in the vessel wall 704 are heated to the point where they permanently contract, the vessel 200 or 202 is occluded and ultimately resorbed. The device includes a laser 102 delivered via a fiber optic catheter 300 that may have frosted or diffusing fiber tips 308, or that may be provided with a protective spacer. A motorized pull back device 104 may be used, and a thermal sensor 600 may be used to help control the power required to maintain the proper treatment temperature.
摘要:
A shape memory composition includes an ionomeric elastomer and a low molecular weight additive that forms crystalline domains in the elastomeric ionomer. The amount of additive is effective to provide crystalline domains of a size and distribution effective to provide shape memory to the composition.
摘要:
Disclosed is a process to increase adhesion between two adjacent layers. The process comprises roughening the surface of one layer followed by chlorination of the roughened surface and joining of the layers, or treating the surface of one layer with a silicone-based adhesion promoter and joining the layers. In one preferred embodiment the process comprises roughening the surface of one layer, followed by chlorination of the roughened surface, joining of the layers and post-treatment of the molded layers at an elevated temperature for a predetermined time.
摘要:
The present invention is directed to golf ball cover compositions containing blends of high or low carboxylic acid based copolymers and ethylene copolymers such as ethylene alkyl acrylates. The carboxylic acid groups of the blends are neutralized with metal cations. Golf balls produced with the cover molded thereon exhibit desired properties of distance and high coefficient of restitution without substantially sacrificing and/or improving characteristics like playability and durability when compared to existing covers comprising ionomeric resin blends.
摘要:
A conductive elastomeric foam composite is presented, comprising an elastomer foam and polypyrrole, thiophene, or aniline and derivatives thereof. The foam is manufactured by first diffusing an oxidant into the dense polymer phase of a solvent-swollen foam and then diffusing pyrrole or pyrrole derivative vapor or solution into the dried foam, resulting in an in situ chemical oxidative polymerization of pyrrole at the oxidant site. Only about 5 wt % of conductive polymer is required for observing an insulator to conductor transition. The conductivity of the composite foam can be effectively controlled between 10.sup.-7 and 10.sup.-1 S/cm by varying either the amount of oxidant used and/or the copolymer composition.
摘要:
The present invention is directed to golf ball cover compositions containing blends of high or low carboxylic acid based copolymers and ethylene copolymers such as ethylene alkyl acrylates. The carboxylic acid groups of the blends are neutralized with metal cations. Golf balls produced with the cover molded thereon exhibit desired properties of distance and high coefficient of restitution without substantially sacrificing and/or improving characteristics like playability and durability when compared to existing covers comprising ionomeric resin blends.