Patent GB-866768-A (GB)
Title: Improvements in and relating to polymerization
IPC: C08F4/06
Filed: 1957-12-19
Abstract: An inorganic refractory compound is irradiated with high energy particulate or electromagnetic ionizing radiation and thereafter contacted with an addition-polymerizable ethylenically unsaturated monomer to effect polymerization.  The polymerized product may be treated with an organic solvent to dissolve extractable polymer or with an acid to extract the inorganic compound, if so desired; but the process may provide a method of coating refractory compounds with polymers.  Specified refractory compounds are silica, alumina, zirconia and aluminium silicate, preferably in the form of particles of size less than 0,075 mm.  Irradiation is preferably performed at -80 DEG  to 100 DEG C. with particles or photons having the energy equivalent of an electron beam of at least 0,1 Mev.  Preferably an exposure of at least 0,01 and as high as 1,000-25,000 watt-sec./cm2 and an absorption of at least 0,05 up to 30,000 watt-sec./g are used. The radiation may comprise protons, neutrons, a -particles, deuterons, b -particles, X-rays and g -rays from conventional sources.  Specified monomers are ethylene and isobutylene and (preferably) acrylic and methacrylic acids and amides thereof, acrylonitrile, methyl methacrylate, ethyl acrylate, vinyl and vinylidene fluoride, vinyl acetate, vinyl pyridine, vinyl ethyl ether, 2-chlorobutadiene, 2-fluorobutadiene, chlorotrifluoroethylene, tetrafluoroethylene, said preferred compounds having at least one negative substituent attached to one of the doubly-bonded carbon atoms.  The polymerization preferably takes place at 0 DEG -40 DEG C. in an oxygen-free atmosphere and the monomer may be used in the the liquid or gaseous phase. Polymerization may be performed a considerable time, e.g. 4 days after irradiation: in this case it is preferred to store the irradiated refractory in a vacuum or inert atmosphere at the temperature of dry ice.  The products of the invention particularly when produced from tetrafluoroethylene are stated to be useful as packing material for high temperature use and have increased thermal resistance and mechanical strength; they may also be used as textile delusterants and as pigments. Specification 665,262 is referred to.ALSO:Inorganic refractory substances are activated to induce polymerization of monomers (see Group IV(a)) by irradiation with high energy electro-magnetic or particulate ionising radiation. Specified substances are silica, alumina, zirconia and aluminium silicate, preferably in particulate form, and the products remain active for up to several days especially when stored under an inert atmosphere or in vacuo and at a low temperature.  Irradiation is preferably performed at -80 to 100 DEG C. with particles or photons having the energy equivalent of an electron beam of at least 0.1 Mev.  Preferably an exposure of at least 0.01 and as high as 25,000 watt-sec./m2 and an absorption of at least 0.05 up to 30,000 watt-sec./gm. are used.  The radiation may comprise protons, neutrons, a -particles, deuterons, b -particles, X-rays and g -rays from conventional sources.  Specification 665,262 is referred to.