GB803479A - Vinylic type organosilicon compounds - Google Patents

Abstract

Liquid resinous or rubbery polymers or copolymers are made by subjecting to vinyl polymerization conditions, in the absence or presence of organic vinylic type compounds, one or more of the following acryloxymethyl substituted organosilicon compounds: (1) siloxanes consisting of polymeric units of the general formula <FORM:0803479/IV (a)/1> where R is an hydrogen atom or a methyl radical, each R1 is a monovalent hydrocarbon radical and n is 1 or 2; (2) copolymeric siloxanes in which from 1 to 99 mol. per cent of the units are those defined at (1) above, and the remainder are of the general formula <FORM:0803479/IV (a)/2> where each R11 is a monovalent hydrocarbon, acetoxymethyl or halogenated hydrocarbon radical and m is 0, 1, 2 or 3; (3) organosilicon compounds of the general formula <FORM:0803479/IV (a)/3> In the above organosilicon compounds, which are described or claimed in Specifications 769,953 and 802,969, the R1 radicals may be, e.g. methyl, ethyl, octadecyl, vinyl, allyl, hexenyl, cyclohexyl, cyclohexenyl, cyclopentyl, phenyl, naphthyl, xenyl, tolyl, or benzyl, and the R11 radicals may be R1 or mono- or dichlorophenyl, bromophenyl, tetrafluoroethyl, a ,a ,a - trifluorotolyl, tetrabromoxenyl, chlorocyclohexyl, or chlorovinyl. The preferred acryloxymethyl silicon reactants are those in which R1 and R11 are methyl or phenyl. The optional reactant, viz. the organic vinylic compound (i.e. a compound containing the <FORM:0803479/IV (a)/4> group in a terminal position in the molecule), may be, e.g. vinyl chloride, styrene, divinylbenzene, dichlorostyrene, acrylonitrile, vinylacetate, vinylpyridine, vinylcarbazole, an alkylacrylate, a vinylalkyl ether; vinylidene chloride, an alkylacrylate, a vinylalkyl ether; vinylidene chloride, isobutylene, isopropenyl chloride; methyl or ethyl methacrylate; butadiene, chloroprene, isoprene; or a linear unsaturated polyester of ethylene glycol and maleic, fumaric or itaconic acid; the preferred compounds are methyl acrylate, methyl methacrylate, acrylonitrile, styrene and vinyl acetate. The copolymers may contain from 1 to 99 mol. per cent of units derived from the organosilicon reactant(s) and from 99 to 1 mol. per cent units derived from the vinylic reactant. Polymerization may be effected by conventional bulk, solvent solution or suspension and emulsion polymerization techniques, using conventional physical catalysis, including the use of photopolymerization with light of a wavelength of 1800 to 7000 (alone or in the presence of vicinal polycarboxyl compounds such as biacetyl 2 : 3-pentanedione and benzyl or phenyl glyoxal), ionizing radiation with beta-rays, gamma-rays, X-rays, accelerated electrons, protons, neutrons, deutrons, and alpha particles, e.g. from nuclear reactors, radioactive isotopes, betatrons, cyclotrons, resonant transformers and linear accelerators; or heat alone, or with high pressures, e.g. in systems containing isoprene; but preferably using catalysts such as hydrogen, sodium, benzoyl, diacetyl, lauryl, 3 : 4-dichlorobenzoyl or acetylbenzoyl peroxide; tertiary butyl hydroperoxide; peracetic, monopersuccinic, or perpropionic acid; di-(tertiary butyl) perphthalate di-(tertiary butyl) peradipate or tertiary butyl perbenzoate; diethyl or di-(tertiary butyl) peroxide; ammonium persulphate, potassium permanganate or ozone; or one of the following azo compounds: Me2(NC)CN=NC(CN)Me2, Me.Et(NC)CN=NC (CN)Me.Et, Et2(NC)CN=NC(CN)Et2, Pr2(NC) CN=NC(CN)Pr2, Am.Me(NC).CN=NC(CN) Me.Am, (HOOC.CH2.CH2).Me(NC)CN=NC (CN)Me(CH2.CH2.COOH), (MeOOC).Me2CN= NC.Me2(COOMe), (EtOOC)Me2CN=NC.Me2 (COOEt), and <FORM:0803479/IV (a)/5> wherein Me, Et, Pr, and Am represent methyl, ethyl, propyl and amyl respectively. Friedel-Crafts catalysts, e.g. AlCl3 and BF3 may also be used. In a typical vinylic polymerization technique, emulsion polymerization is effected in an aqueous solution of a water-soluble acid, e.g. acetic acid, with H2O2 and ferric ions present as catalysts, with sodium stearate, sodium salt of an acid sulphuric ester of a high molecular weight alcohol, a sulphonate, gelatin, albumin or coconut oil soap as emulsifying agent. Tannic acid can be added as an inhibitor; chlorobenzene or CCl4 can be used as a reaction activator in systems containing, e.g. acrylonitrile, though CCl4 prevents excessive branching in systems containing, e.g. butadiene. Reaction temperatures may vary from room temperature to 400 DEG C. In typical examples: (1) methacryloxymethylpentamethyldisiloxane was polymerized to a resilient plastic material by heating with benzoylperoxide at 70 DEG C. under N2 for 2 hours; (4) a siloxane copolymer containing vinylmethyl-, chlorophenylmethyl-, dimethyland acryloxymethylmethyl-siloxane units was mixed with a silica aerogel filler and benzoyl peroxide and heated at 100 DEG C. to yield a tough rubber; (6) mixtures of methacryloxymethylpentamethylolisiloxane and methylmethacrylate were polymerized by using a ,a 1-azodi-iso-butyronitrile as catalyst. Uses.-The polymers and copolymers find use as moulding and impregnating resins, electrical insulating varnishes, water repellents, lubricants, thermally resistant rubbers and resins, coating agents, bonding agents and adhesives; the unique property of extremely low coefficient of friction (stated to be the lowest yet for solid materials in the absence of oil lubrication) suggests their use for watch bearings and the like.