Abstract: A hypodermic needle of the present invention includes an elongate hollow tube with a proximal end, a distal end and has a bore therethrough. The proximal end of the needle of the invention has a hub fixedly attached thereto to connect the needle releasably to a fluid handling device with the distal end having a point for facilitating penetration of the needle into a patient's tissue. The outside surface of the tube has a proximal portion with a lower coefficient of sliding friction with the patient's tissue than the coefficient of sliding friction with the patient's tissue than a distal portion of the outside surface of the tube. The higher coefficient of friction of the distal portion enables a practitioner to substantially discriminate the needle's penetration of structures in the patient's tissue while the lower coefficient of friction proximal portion substantially reduces drag force for passage of the proximal portion through the structures already penetrated by the distal portion.

Abstract: Copolymer-containing compositions are prepared by the reaction of an epoxytriazine-capped polyphenylene ether with another polymer containing amine end groups, especially a polyamide, under intimate blending conditions. The compositions have excellent properties and find utility as molding compositions and as compatibilizers for blends of similar polymers. Suitable epoxytriazine-capped polyphenylene ethers may be prepared by reaction of a polyphenylene ether with an epoxychlorotriazine such as diglycidyl chlorocyanurate, n-butyl glycidyl chlorocyanurate or mesityl glycidyl chlorocyanurate.

Abstract: Polymers, such as polyphenylene ethers, are isolated from solution in an extruder by addition of at least one non-solvent. Optional steps include removal of volatiles through vents or ports on the extruder and employment of an auxiliary non-solvent. Additional operations, such as blending with further polymers, fractionation of low molecular weight molecules and functionalization by chemical reaction, may also be performed in the extruder.

Abstract: Copolymer-containing compositions are prepared by the reaction of an epoxytriazine-capped polyphenylene ether with another polymer containing amine end groups, especially a polyamide, under intimate blending conditions. The compositions have excellent properties and find utility as molding compositions and as compatibilizers for blends of similar polymers. Suitable epoxytriazine-capped polyphenylene ethers may be prepared by reaction of a polyphenylene ether with an epoxychlorotriazine such as diglycidyl chlorocyanurate, n-butyl glycidyl chlorocyanurate or mesityl glycidyl chlorocyanurate.

Abstract: Impact-improved polyphenylene ether resin compositions which also exhibit improved melt behavior without degradation of other themal properties are provided by combining a polyphenylene ether polymer, an alkyl or aralkyl sulfonate of an alkali metal, where the alkyl or aralkyl radical has 5 to 25 carbon atoms, and an acrylate-styrene-acrylonitrile terpolymer.

Abstract: Polymer compositions comprising polyphenylene ethers free from polystyrenes are extruded with vacuum venting at 300.degree. C. or above in the presence of water. This extrusion operation reduces the content of volatile impurities, including those with an undesirable odor.

Abstract: On-line rheological measurements are made utilizing a rheometer of the type in which a first metering pump delivers diverted melt from a process main stream to a capillary passage and a second metering pump returns the diverted melt from the capillary passage to the process main stream and the viscosity of the diverted melt is measured by controlling the rate of flow of the melt to maintain constant the pressure drop between spaced apart locations along the capillary passage and measuring the temperature of the melt in the capillary passage. The measurements may be made while controlling the speed of the second metering pump independent of the speed of the first metering pump to maintain the pressure at the exit of the capillary passage essentially constant.

Abstract: A method is provided for producing thermoplastic polymer blends with the exposure of blend constituents to extreme blending conditions minimized by melting the thermoplastic polymers and adjusting their viscosity and elasticity values, through control of their melt temperatures, prior to blending. Where the viscosity and elasticity values are adjusted properly, the desired thermoplastic polymer blend can be produced with a minimum effort.

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 for determining the concentration of additives in a compounding process by measuring the capacitance and dissipation factor (tan.delta.) of the mixture and converting such values to the concentrations of the additives. This method may also be utilized to determine the concentration of the polymers in the mixture. This method is preferably applied to a compounding process of blending polyphenylene oxide and polystyrene thermoplastic resins and is preferably applied to a continuous compounding process of these resins to determine therein the concentration of an aryl phosphate ester flame retardant.

Abstract: Blends of polyetherimides and block poly(esteramides) may contain about 99-1% by weight of the former and about 1-99% of the latter. Particularly useful are polyetherimides containing about 1-30% of the block poly(esteramide), which have improved impact strength and resistance to brittleness. The blends may also contain at least one poly(alkylene dicarboxylate) as a compatibility improver.

Abstract: A method for determining the concentration of ingredients and other process variables in a polymerization process by measuring the capacitance and dissipation factor of the mixture and determining its dielectric constant at various stages of the process. By the use of an automatic capacitance bridge and a computer, the process variables can be determined and controlled in a matter of seconds.

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.