A new class of compounds: R--W--R' were R and R' are identical oxy radicals containing peroxide functions such as dialkyl or diaralkyl peroxide, peroxyketal, peroxyester, or monoperoxycarbonate, and W is a carbonyl group, or carbonyl containing group, or an alkylidene or aralkylidene group, or a phosphorus containing group. Examples Di[1,3-dimethyl-3-(t-butylperoxy)butyl]carbonate; Di[1,3-dimethyl-3-(n-butoxycarbonylperoxy)butyl]carbonate; 2,2-Bis[3,3-di(t-butylperoxy)butoxy]propane; Di[1,3-dimethyl-3-(t-butylperoxy)butyl]ethyl phosphate. They are free radical affording compounds useful in crosslinking of polyolefins and unsaturated polymers, and for the polymerization of vinyl monomers and diolefinic monomers.
RELATED APPLICATIONS
This application is a continuation in-part of application Ser. No. 342,111, filed Mar. 16, 1973, now abandoned, which in turn is a division of application Ser. No. 737,359, filed June 17, 1968 (now U.S. Pat. No. 3,725,455).
A process for the cross-linking or chain-extension of hydrocarbon polymers which contain ethylenically unsaturated groups which comprises forming an intimate mixture of the polymer with a mono-sulphonyloxycarbamate of the formula: wherein A is an alkyl group, a cycloalkyl group, an alkenyl group, a substituted alkyl group, a substituted aryl group or a heterocyclic group, and R is an optionally substituted alkyl or aryl group. The process is useful for natural and synthetic rubbers. The rate and extent of cross linking may be modified by the additives such as tertiary amines or conventional rubber additives e.g. tetramethyl and zinc diethyl dithiocarbamates, which contain tertiary amino groups.
A process for modifying a polypropylene (co)polymer wherein said process comprises melt mixing the polypropylene (co)polymer in the presence of an initiator wherein said initiator is selected from the group defined by formula (1), wherein R is selected from the group consisting of optionally substituted C.sub.1 to C.sub.18 acyl, optionally substituted C.sub.1 to C.sub.18 alkyl, aroyl defined by formula (2), and compounds of formula (3), wherein U, V, X, Y, Z, U', V', X', Y' and Z' are independently selected from the group consisting hydrogen; halogen; C1-C18 alkyl; C1-C18 alkoxy, aryloxy, acyl, acyloxy, aryl, carboxy, alkoxycarbonyl, aryloxycarbonyl, trialkyl silyl, hydroxy, or a moiety of formula (4), and wherein T is alkylene.
A process for the free radical polymerization of vinyl monomers, including vinyl aromatic monomers, wherein the temperature of the polymerization is progressively increased by at least 30.degree. C during the period of the polymerization a temperature range of from 50.degree. C to 160.degree. C and wherein the final temperature is at least 110.degree. C, the polymerization mass including an initiator sensitive to produce free radicals near or at the low temperature end of the range and an initiator sensitive to produce free radicals near or at the high temperature end of the range. A single entity initiator may contain peroxide functions that are actuated to produce free radicals at each of the temperature extremes of the process.
