GB1288816A - - Google Patents

Abstract

1288816 Conductive polymer compositions MATSUSHITA ELECTRIC INDUSTRIAL CO Ltd 23 Dec 1969 [27 Dec 1968 (3)] 62758/69 Headings C3B C3P and C3R [Also in Divisions F2 and H1] A channel electron multiplier comprises a flexible tube of a resistive secondary-emissive polymer which is preferably bent into a semicircle (Fig. 7, not shown) or into a helix as shown in Fig. 6. The input end of the tube may expand into a horn of circular or of rectangular crosssection. The tube may have internal and external diameter of 2 mm. and 1 mm. respectively and be 10 cm. in length with a resistance of 6 Î 10<SP>11</SP> ohms. The multiplier may be used as the detector of a mass spectrometer, as the detector of a device for measuring ions or electrons in space, or in an image intensifier. Materials.-One suitable material comprises 35 g. of lithium- or potassium-tetracyanoparaquinodimethane, 30 g. of polyvinyl chloride (average polymerization 1,200), 30 g. of low molecular weight polyurethane, and 5 g. of stabilizer (equivalent mixture of tribasic lead sulphate and Cd-Ba type stabilizer). Another composition comprises 35 g. sodium-tetracyanoparaquinodimethane, 45 g. PVC, 55 g. polyurethane and 10 g. stabilizer. In a further example a styrene-ethylacrylate-2-vinylpyridine copolymer (at a ratio of 40:40:20) is dissolved in toluene, quaternarized by hydriodic acid, dissolved in acetonitrile and reacted withlithium-tetracyanoparaquinodimethane to form a material which is flexible and mouldable, and which is moulded into a pipe. In another example poly-2-vinylpyridine is dissolved in ethanol, quaternarized by hydriodic acid, and dissolved in a solvent of water and ethanol. This is mixed with an aqueous solution of lithium-tetracyano-paraquinodimethane to form a precipitate which is blended with PVC, polyurethane, and stabilizer in the proportions 50: 30: 25: 5. Alternative compositions comprise polymers with carbon or metal powder added to give the required electrical conductivity. One example of this comprises 90 g. of an intermediate density polyethylene with 10 g. of carbon black. Another example comprises 30 g. polyamide with 100 g. of an epoxy resin and 10 g. of a conductive silver powder; the mixture is poured into a mould and cured for 1 hour at 60‹ C.