A process for copolymerising unsaturated monomers and the copolymers produced thereby

Abstract

Abstract A vinyl-type monomer possessing a terminal methylene group joined through a double bond to an aliphatic carbon atom which is joined through a double bond to an aliphatic carbon atom which is joined through a single bond to an atom or group other than hydrogen and through the other single bond to a carbon atom of an organic radical, or a vinyl-type monomer having a terminal methylene group joined to an aliphatic carbon atom through an ethylenic linkage which is in conjugated relationship with another ethylenic linkage, is copolymerized with a dissimilar polymerizable olefinically unsaturated compound by a process which comprises initially polymerizing the vinyl-type monomer under conditions which promote the formation of active polymer nuclei, including polymerization in a liquid medium in which the polymer of the vinyl-type monomer is substantially insoluble, until there is substantially no unpolymerized monomer in the reaction mixture, and thereafter adding the dissimilar polymerizable olefinically unsaturated compound and continuing polymerization. Preferred vinyl-type monomers include methacrylonitrile, methyl methacrylate, methyl-alpha-chloracrylate, methyl isopropenyl ketone, isobutyl 4-ethyl-4-pentenoate, amyl 4-amyl-4-pentenoate, 4 - butyl - 4 - pentenenitrile, butyl 4 - chloro - 4 - pentenoate, 4 - isobutyl - 4 - pentenamide, 4 - amyl - 4 - pentenamide, 3 - chloro - 3 - buten - 2-one, and 4-isopropyl-4-penten-3-one, and preferred dissimilar compounds include acrylonitrile, methacrylonitrile, ethacrylonitrile, styrene, vinylidene chloride, vinyl chloride, bromide, fluoride and acetate, methyl methacrylate, butyl acrylate, acrylic acid, methacrylic acid, methyl isopropenyl ketone and allyl methallyl ether. The Specification contains lists of other suitable monomers. The polymerization may be conducted in aqueous emulsion or suspension or the liquid medium may be an organic liquid such as cyclohexane, butane, hexane or benzene, or the monomer itself. Emulsifying agents employed may be soaps, alkali metal alkyl or alkylene sulphates or sulphonates or salts of higher amines. The polymerization may be initiated by heat, light, particularly ultra-violet light, or a catalyst which may be benzoyl, acetyl, hydrogen or tertiary-butyl peroxide, persulphuric, peracetic or perphthalic acid, potassium persulphate or tertiary-butyl perbenzoate. Mixtures of catalysts may be used, and polymerization preferably takes place in the absence of oxygen. Multiple component copolymers can be formed if the second and, if desired, subsequent polymerizations utilize vinyl compounds of the same type as the first monomer. A mixture of two or more vinyl-type monomers may be initially polymerized and two or more dissimilar polymerizable olefinically unsaturated compounds may be added after the polymerization of the vinyl-type monomer or monomers.

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