Abstract: A diagnostic catheter comprises an inner layer of substantially unmodified polyamide over which is a reinforcing means and an outer layer of polymer having a hardness of 50 Shore D to 70 Shore D, along with a suitable radiopaque filler. Affixed either directly to the end of the above tubular body or to a stem member secured to that tubular body is a soft-tip formed from a blend of PEBA whose hardness is such that the catheter can be considered as having an atraumatic tip. The resulting catheter exhibits excellent torque and column strength characteristics while providing a relatively large diameter lumen for a given outside diameter.

Abstract: A diagnostic catheter comprises an inner layer of substantially unmodified polyamide over which is a reinforcing means and an outer layer of polymer having a hardness of 50 Shore D to 70 Shore D, along with a suitable radiopaque filler. Affixed either directly to the end of the above tubular body or to a stem member secured to that tubular body is a soft-tip formed from a blend of PEBA whose hardness is such that the catheter can be Considered as having an atraumatic tip. The resulting catheter exhibits excellent torque and column strength characteristics while providing a relatively large diameter lumen for a given outside diameter.

Abstract: An intravascular catheter having an elongated tubular body with a proximal portion, a distal portion and a lumen extending therebetween. The tubular body is formed with: (a) an inner layer of a blend of (i) about 10-25 weight percent of a polyester-polyurethane having a durometer of from about 45D-55D, and (ii) about 38-53 weight percent of a polyester polyurethane having a durometer of from about 65D-75D; (b) a reinforcing means at least partially surrounding the inner layer; and (c) an outer layer comprising a blend of (i) about 10-25 weight percent of a polyester-polyurethane having a durometer of from about 45D-55D and (ii) about 38-53 weight percent of a polyester-polyurethane having a durometer of from about 659D-75D.

Abstract: A catheter includes a catheter tube extending to a distal end portion that terminates at a terminal end of the catheter tube, the distal end portion including a tapered portion extending between the terminal end and a transition region on the distal end portion set back slightly from the terminal end. The tapered portion has a cross sectional area that decreases toward the terminal end to define a frustoconically-shaped outer surface extending from the transition region to the terminal end on which a soft tip member is mounted. The tip member has a size and shape adapted to be placed over the tapered portion coaxially, and a composition softer than that of the distal end portion that is suitable for bonding to the frustoconically-shaped outer surface.

Abstract: A feed pipe is provided for introducing highly reactive monomers into a continuous reactor to effect polymerization of such reactive monomers. The feed pipe has concentric tubes forming a central flow channel and an annular flow channel which are sized to insure laminar flow within said tubes. The feed pipe is particularly useful for feeding melts of organic dianhydride and organic diamine into an extrusion reactor for polyetherimide preparation.

Abstract: A continuous process for incorporating additives into a thermoplastic fluid blend is provided; said additives typically being sensitive to the temperature at which the blend is produced, said process comprising the steps of blending a high viscosity silicone fluid and thermoplastic composition initially and feeding the additives with more thermoplastic into the extruder for blending.

Abstract: A method of continuously producing blends of thermoplastic polymers and high viscosity silicone fluids is provided by injecting the silicone fluid into an extruder where the thermoplastic polymers are molten. The dispersion of the silicone fluid can be controlled by adjusting the blending temperature and blends having superior engineering properties and flame retardance produced.

Abstract: Polyetherimides are formed by the blending of a first melt of organic dianhydride and a second melt of organic diamine and the resulting blend is polymerized in a continuous, steady state manner, employing an extruder reactor as the reaction chamber. The extruder reactor is provided with means for heating, evacuation of water of reaction, and transfer sections in order to achieve the steady state necessary for continuous production of a substantially uniform polyimide.

Abstract: Polyetherimides are formed by the dry blending of organodianhydride, organic diamine, and chain stopper and the polymerization of the dry-blended mixture in a continuous, steady state reaction, employing an extruder reactor as the reaction chamber. The extruder reactor is provided with means for heating and cooling, evacuation of water of reaction, and material conveyance means in order to achieve a steady state necessary for continuous production of a uniform polymeric product.

Abstract: Polyetherimides are formed by the dry blending of organodianhydride, organic diamine, and chain stopper and the polymerization of the dry-blended mixture in a continuous, steady state reaction, employing an extruder reactor as the reaction chamber. The extruder reactor is provided with means for heating and cooling, evacuation of water of reaction, and material conveyance means in order to achieve a steady state necessary for continuous production of a uniform polymeric product.

Abstract: Compositions or composites comprising a polyphenylene ether-styrene resin blend or composition are disclosed which have electromagnetic shielding properties so that when the compositions are used for electronic equipment components or housings they provide shielding against electromagnetic interference referred to as EMI. The composites eliminate the secondary treatments which have been used heretofore to provide these shielding properties, such as the application of electrically conductive silver, nickel, copper and graphite coatings, or the use of metal screens. The novel compositions of a polyphenylene ether-styrene blend contain as a conductive material, which attenuates the EMI, aluminum flakes, or a combination of aluminum flakes with carbon fibers or with a highly conductive carbon black or a combination of carbon fibers with conductive carbon black, or carbon fibers per se.