Abstract: A composition comprising: polyethylene; as a scorch inhibitor, 2,4-diphenyl-4-methyl-1-pentene; as a cure booster, 3,9-divinyl-2,4,8,10-tetra-oxaspiro[5.5]undecane; and an organic peroxide.

Abstract: Polyisobutylene (PIB) functionalized with terminal reactive unsaturation is disclosed. Carbocationically polymerized monohalogen-terminated PIB is dehydrohalogenated in a hydrocarbon solvent using an alkoxide of the formula RO-M wherein R is alkyl of at least 5 carbon atoms and M is alkali metal. The PIB obtained has terminal unsaturation which is 100% in the reactive ‘exo’ form which can be converted to succinic anhydride groups (PIB-SA) by the ene reaction with maleic anhydride. The PIB-SA is reactive with amine functional dendrimers to obtain a star-branched polymer having a dendrimer core and PIB branches joined by succininide linkages. Blends of the star-branched polymer with polypropylene have improved energy absorption properties and controllable moisture/oxygen permeabilities useful in films.

Abstract: Disclosed is a polypropylene molding material obtained by the reaction of a crystalline polypropylene resin and a peroxide, said polypropylene molding material having (A) a melt flow rate of 20 to 100 g/10 min and a weight average molecular weight to number average molecular weight ratio of 1.5 to 3.5 as measured by gel-permeation chromatography, (B) a content of hydrocarbons having 20 to 70 carbon atoms of 0.05% by weight or less, (C) a mean elution temperature (T50) of 75 to 120° C. and a degree of variation of elution (&sgr;) of 9 or smaller, and (D) a Q2/Q1 ratio of 0.75 to 0.95, wherein Q1 is a weight average molecular weight to number average molecular weight ratio of said crystalline polypropylene resin as measured by gel-permeation chromatography, and Q2 is a weight average molecular weight to number average molecular weight ratio of said propylene molding material as measured by gel-permeation chromatography.

Abstract: A composition comprising: (a) polyethylene; (b) as a scorch inhibitor, 4,4′-thiobis(2-methyl-6-t-butylphenol); 2,2′ thiobis(6-t-butyl-4-methylphenol); or mixtures thereof; (c) optionally, a cure booster; and (d) an organic peroxide.

Abstract: A rubber composition which contains a rubber mixture that can be vulcanized with a vulcanizing agent, which includes at least one rubber component, at least one filler having nucleophilic groups, gel particles comprising a rubber, having a particle size between about 3×10−9 and about 1×10−6 m and a swelling index in toluene of about 1 to about 15 and whose surface has electrophilic centers, and a substance acting as a coupling agent between the filler having nucleophilic groups and the additional filler, the substance acting as a coupling agent having the following structure: X—R1—Si—(R2)3, wherein X is a nucleophilic group, R1 is an alkyl group having up to about 6 carbon atoms or a phenyl group, and R2 may be the same as or different from each other and from R1 and is an alkyl or alkoxy group having up to 6 carbon atoms and at least one of R2 is an alkoxy group.

Abstract: A composition comprising: (a) a low density homopolymer of ethylene prepared by a high pressure process; (b) a scorch inhibitor selected from the group consisting of a substituted hydroquinone; 4,4′-thiobis(2-methyl-6-t-butylphenol); 2,2′-thiobis(6-t-butyl-4-methylphenol); and 4,4′-thiobis(2-t-butyl-5-methylphenol) in an amount of about 0.02 to about 0.07 part by weight of scorch inhibitor per 100 parts by weight of homopolymer; (c) a cure booster; and (d) an organic peroxide.

Abstract: A block copolymer having (meth)acryloyl groups in side chains, which copolymer is a ring-opening addition product of (meth)acryloyl-group-containing carboxylic acid to epoxy groups of a block copolymer obtained through epoxidation of double bonds derived from a conjugated diene compound contained in a base block copolymer formed of a polymer block of an aromatic vinyl compound and that of a conjugated diene compound; as well as adhesive compositions, sealant compositions, coating compositions, and sizing compositions.

Abstract: A fluorinated oligomer having COOH groups at both end and a &rgr;50° value of 1,000 to 10,000 is produced by swelling a fluorine rubber crosslinking product in an organic solvent, followed by decomposition in the presence of a base and a peroxide. The obtained fluorinated oligomer is soluble in solvent and thus easy to separate from fillers, etc., and can be effectively used as a chain-elongating agent for epoxy resin, isocyanate resin, oxazoline resin, etc.

Abstract: A thermoplastic elastomer composition containing a component (A) (thermoplastic polyolefin resin), component (B) (epoxy-group-containing ethylene acrylic ester copolymer rubber), and component (C) (acid-modified polyolefin resin) comprising a continuous phase of the component (A) in which the component (B) is dispersed as a dispersed phase and is cross-linked by a peroxide; a thermoplastic elastomer composition comprising a continuous phase of a thermoplastic polyolefin resin (A) and a dispersed phase of an epoxy-group-containing ethylene-acrylic ester copolymer rubber component (B) and acrylonitrile butadiene rubber component (C), which is dynamically cross-linked; and a hose having an inner tube, at least one reinforcing layer, and an outer cover, wherein the inner tube and the outer cover contain a thermoplastic elastomer composition comprised of a thermoplastic resin in which is blended an at least partially cross-linked elastomer component, the reinforcing layer is a brass-plated wire, and the reinforcin

Abstract: Thermoplastic polymer alloy compositions and a process for preparing the compositions are provided comprising a blend of polypropylene, uncrosslinked ethylene copolymer, ionomeric copolymer of ethylene and .alpha.,.beta.-unsaturated C.sub.3 -C.sub.8 carboxylic acid, crosslinking agent, and silicone elastomer. The compositions may further comprise particulate filler, color concentrate and/or coloring pigment. The compositions are particularly useful for forming interior skin sheets for applications where low gloss and high scuff resistance are desired without the need for painting. A one step process for preparing moldable sheets from the thermoplastic polymer alloy compositions by in-line compounding and reactive extrusion is also provided which eliminates separate compounding and pelletizing processing steps as precursors to the sheet extrusion process.

Abstract: A water-soluble polymer having a low polydispersity index and controlled molecular weight can be prepared by oxidative degradation and shearing of a water-swellable crosslinked polymer or by hydrolysis of the crosslinked polymer to a high molecular weight soluble polymer, followed by oxidative degradation of the high molecular weight polymer.

Abstract: Disclosed is an olefin thermoplastic elastomer composition obtained by dynamically heat treating, in the presence of an organic peroxide, a blend comprising 10 to 60 parts by weight of a crystalline polyolefin resin (A) and 40 to 90 parts by weight of an unsaturated olefin copolymer (B) of at least one .alpha.-olefin of 2 to 20 carbon atoms, a conjugated diene monomer represented by the following formula (I), and optionally, an aromatic vinyl compound, the total amount of said components (A) and (B) being 100 parts by weight; ##STR1## wherein R.sup.1 and R.sup.2 are each independently a hydrogen atom, an alkyl group of 1 to 8 carbon atoms or an aryl group, and at least one of R.sup.1 and R.sup.2 is a hydrogen atom. The composition has excellent moldability and can provide a molded product having excellent elastomeric properties, tensile strength properties and appearance.

Abstract: Process for the treatment of ground polyolefin material originating from scrap dairy product containers with at least one agent chosen from hydrogen peroxide, steam and sodium hydroxide in a quantity which is effective for deodorizing the polyolefin. Ground material obtained by this process and exhibiting an imperceptible level of residual odour of aged milk. Use of the deodorized ground material obtained by this process for the production of shaped objects.

Abstract: A thermoplastic molding composition comprises, in each case based on the total of A to E,at least 3% by weight, but not more than 30% by weight, of a polyphenylene ether A,at least 10% by weight, but not more than 65% by weight, of an impact-modified styrene polymer B,at least 30% by weight of a (standard) styrene polymer C which is not impact-modified,from 0.05 to 5% by weight of a free-radical generator D,from 1 to 20% by weight of a phosphorus-containing flame retardant E, in particular an organophosphorus compound, such as triphenyl phosphate or triphenyl phosphine oxide.

Abstract: Perfluoroelastomer compositions are provided which have excellent high temperature properties. The perfluoroelastomer component of the compositions are copolymers having a plurality of carbonyl-containing functional groups and copolymerized monomer units comprising a perfluoroolefin, a perfluoro(vinyl) ether and a nitrile-containing cure site monomer. The curative component is other than an organotin compound and includes peroxides, ammonium salts, aromatic amino compounds, bisamidrazones, and bisamidoximes.

Abstract: The subject invention is directed to a rheology-modified ethylene polymer having less than 0.5 weight percent gel, a composition distribution breadth index (CDBI) greater than 50 percent, and a molecular weight distribution (M.sub.w /M.sub.n) of less than 4.0, which is characterized as having improved rheological performance and/or melt strength attributes relative to the unmodified polymer. The subject invention is further directed to polymer blends which comprise the rheology-modified polymers, and to a process for preparing the rheology-modified polymers.

Abstract: O-rings obtainable from vinylidenfluoride (VDF)-based ionically cured copolymers having compression set lower than 20%.

Abstract: Molding materials modified with acrylic rubber are prepared by means of groups which are incorporated in the acrylic rubber and are decomposed by a redox component to give free radicals.

Abstract: The invention pertains to a process for enhancing the melt strength of a polypropylene (co)polymer with the aid of initiator dispersions. The use of initiator dispersions with a particulate initiator instead of the corresponding non-dispersed initiators or their dilutions or solutions results in a significant enhancement of the melt strength of the modified polymer, and a wide range of initiators turn out to be serviceable.

Abstract: A composition comprising:(a) polyolefin;(b) as a scorch inhibitor, 4,4'-thiobis(2-methyl-6-t-butyl phenol); 2,2'-thiobis(6-t-butyl-4-methylphenol); or mixtures thereof;(c) hydroquinone; a substituted hydroquinone; or mixtures thereof in an amount sufficient to control color formation; and(d) an organic peroxide.

Abstract: A method of (co)polymerizing vinyl and/or diene monomers comprising contacting the monomers with a (co)polymeriztion composition under conditions effective to (co)polymerize the monomers, wherein the (co)polymerization composition comprises: (a) an organic peroxide component, and (b) a heteropoly acid, in an amount effective to lower the onset temperature of decomposition of the organic peroxide component with the proviso that if the heteropoly acid is phosphomolybdic acid the organic peroxide is not a peroxydicarbonate.

Abstract: A rubber layer structure provided with a first rubber layer having a first liquid facing surface for contact with a liquid surface and a second rubber layer in contact with a second surface of the first rubber layer. The first rubber layer is formed of a peroxide vulcanization first rubber compound which mainly comprises EPDM, contains sulfur powder as a co-crosslinking agent and does not contain a zinc compound. The second rubber layer is formed of a sulfur vulcanization second rubber compound which mainly comprises EPDM and contains a zinc compound. The first rubber layer and the second rubber layer are adhered together by vulcanization.

Abstract: The present invention provides a method for creating durable blends of polystyrene and polyolefin. The blends of the present invention have improved mechanical properties evidenced by measurement of impact strength, tensile strength, and elongation at break. Polyolefin is first crosslinked by creating a melt of polyolefin and a small amount of peroxide in a mixer at elevated temperature. The crosslinked polyolefin is then melt-blended with polystyrene at elevated temperature. Finally, a styrene-butadiene-styrene block copolymer is mixed into the melt. The method of the present invention can be applied to various blend systems of otherwise incompatible polymers provided it contains at least one component and a compatibilizer that are crosslinkable.

Abstract: A thin walled natural rubber latex material is disclosed suitable for forming thin walled products including gloves, dental dams and shields, catheter tubing, penrose surgical drains, finger cots, coverings for body parts, and the like. The thin walled material is formed from a latex emulsion containing natural rubber, sulphur-free, oxygen-donating curing agents, and a strength enhancing agent which may be an inorganic substance such as fumed silica and/or an organic substance such as monomers and polymers of families of acrylics and esters. The emulsion also preferably includes microcrystaline wax as an oxygen barrier, and the material is also provided with a heat resistant and water resistant coating which blocks transfer of latex proteins from the material and enhances slip of the material.

Abstract: A rubber composition comprising the following components (A) to (C) and comprising no zinc-containing compound:(A): an ethylene-.alpha.-olefin copolymer rubber, ethylene-.alpha.-olefin-nonconjugated diene copolymer rubber, or, ethylene-.alpha.-olefin copolymer rubber and ethylene-.alpha.-olefin-nonconjugated diene copolymer rubber,(B): magnesium oxide, and(C): carbon black.

Abstract: A novel, continuous process for the manufacture of novel higher molecular weight and higher acid numbered maleated polypropylenes with lower color at higher efficiencies involving specified ratios of polypropylene, maleic anhydride, and free radical initiator is described. The novel maleated polypropylenes have an acid number greater than 4.5, a yellowness index color of no greater than 76, and a number average molecular weight of at least 20,000. The process entails continuously forming an intimate mixture of molten polypropylene and molten maleic anhydride at one end of a reactor, continuously introducing a free radical initiator, and continuously removing high acid number high molecular weight maleated polypropylene of low color from the opposite end of the reactor.

Abstract: Elastomeric vinylidene fluoride-containing copolymers are cured by a sequential process. In a first step, gum fluoroelastomer is mixed at a temperature of 150.degree. C.-250.degree. C. in the presence of an organic base and metal oxide or metal hydroxide to generate an unsaturated product. The unsaturated product is mixed with a polyhydroxy compound, polyamine, or organic peroxide and the resultant compounded fluoroelastomer is crosslinked.

Abstract: An effective production method for silane-treated clays having exceptional reinforcing effects with respect to rubber, and compositions using these silane-treated clays are offered. With the silane-treated clay production method, a functional silane is predispersed or emulsified in water by means of a surfactant in order to mix the functional silane with kaolin clay and thereby uniformly surface-treat the kaolin clay with the functional silane. The surfactant should preferably be a non-ionic surfactant with an HLB value in the range of 8-18. The silane-treated clay formed by surface-treating kaolin clay by means of these functional silanes characteristically contains low residual levels of the non-ionic surfactants. The functional silanes can be either vinyl or sulfur functional silanes. The silane treated clays are useful as fillers or extenders in rubber compositions, particularly those employing silicas and/or carbon blacks.

Abstract: The present invention relates to partially crystalline polypropylene homopolymer or copolymer waxes modified so as to be polar and having an acid or saponification number of from 0.5 to 120 mg KOH/g, a melt viscosity of from 20 to 50,000 mPa.s/170.degree. C. and a softening point (ring/ball) of from 90 to 165.degree. C., prepared by reacting a nonpolar polypropylene homopolymer or copolymer wax with an .alpha.,.beta.-unsaturated carboxylic acid or a derivative thereof in the presence of free-radical formers, wherein the nonpolar polypropylene wax has been prepared by direct polymerization of propylene or copolymerization of propylene with higher 1-olefins using catalysts of Ziegler or metallocene type and has a softening point (ring/ball) of from 90 to 165.degree. C.The waxes are useful as plastics additives, for aqueous dispersions or for melt adhesive formulations.

Abstract: Peroxidic compositions utilizable for curing elastomers and polyolefins having scorch retardant properties, which comprise:(A) a peroxide in powder or in the form of granules or master batch(B)+(C) inhibitor and promoter in powder, granules or master batch,wherein (B) is an inhibitor derived from hydroquinone and (C) is a curing promoter.

Abstract: Method of grafting a water-soluble organic oligomer(s) to an organic polymer(s) in aqueous latex form, which method comprises forming a water-based mixture of a water-soluble oligomer(s), an aqueous latex of a polymer(s), and at least one free radical polymerisable monomer, both of said oligomer(s) and polymer(s) being preformed, and carrying out free radical polymerisation of said at least one monomer to effect grafting between said oligomer(s) and said polymer(s).

Abstract: Blends of meta and para isomers of .alpha., .alpha.'-bis(t-butylperoxy) diisopropylbenzene are disclosed as well as methods of producing blends of .alpha., .alpha.'-bis(t-butylperoxy) diisopropylbenzene with desired ratios of meta and para isomers.Additionally, blends of meta and para isomers of .alpha., .alpha.'-bis(t-butylperoxy) diisopropylbenzene and tertiary alkyl cumyl peroxides are disclosed.The peroxides are useful for absorbing in polymers and subsequently crosslinking the polymers. The peroxide blends may be adjusted to have melt points below temperatures at which the polymers become difficult to process during the absorption step because of stickiness.

Abstract: The subject invention provides a thermoset elastomer comprising a crosslinked pseudorandom or substantially random interpolymer of: (a) from 15 to 70 weight percent of at least one .alpha.-olefin, (b) from 30 to 70 weight percent of at least one vinylidene aromatic compound, and (c) from 0 to 15 weight percent of at least one diene. The subject invention further provides a thermoplastic vulcanizate comprising the thermoset elastomers of the invention as provided in a thermoplastic polyolefin matrix. The subject invention further provides processes for preparing the inventive thermoset elastomers and thermoplastic vulcanizates, as well as parts fabricated therefrom. The inventive materials have a superior balance of properties, as compared to EPM and EPDM based materials. The subject invention also pertains to foams and methods for their preparation.

Abstract: A rubber composition of low compression set comprising 100 parts by weight of a mixture and 0.1 to 15 parts by weight of a peroxide crosslinking agent admixed therewith, the mixture comprising 5 to 55 wt. % of a peroxide-crosslinkable fluororubber containing vinylidene fluoride copolymerized therein in a proportion of 45 to 88 mole % and having a number average molecular weight of 20,000 to 200,000, and 95 to 45 wt. % of an acrylic rubber containing 0.1 to 1.5 wt. % of a polyfunctional monomer copolymerized therein and having a functional group rendering the acrylic rubber peroxide-cocrosslinkable with the fluororuber and a functional group effecting the copolymerization of the monomer with an acrylic ester, and molded product prepared from the composition.

Abstract: A novel, continuous process for the manufacture of novel higher molecular weight and higher acid numbered maleated polypropylenes with lower color at higher efficiencies involving specified ratios of polypropylene, maleic anhydride, and free radical initiator is described. The novel maleated polypropylenes have an acid number greater than 4.5, a yellowness index color of no greater than 76, and a number average molecular weight of at least 20,000. The process entails continuously forming an intimate mixture of molten polypropylene and molten maleic anhydride at one end of a reactor, continuously introducing a free radical initiator, and continuously removing high acid number high molecular weight maleated polypropylene of low color from the opposite end of the reactor.

Abstract: A process for the modification of (co) polymers employing an organic peroxide comprising the step of contacting a (co) polymer with organic peroxide under conditions whereby at least some of the said organic peroxide is decomposed, is disclosed. The process is characterized in that at least 20% of the total active oxygen content of said organic peroxide is attributable to one or more cyclic ketone peroxides. In a second aspect, the invention relates to the use of an organic peroxide composition wherein at least 20% of the total active oxygen content is contributed by one or more cyclic ketone peroxide(s) modify (co) polymers. It has been found that these cyclic ketone peroxides are extremely efficient in (co) polymer modification processes.

Abstract: A process for preparing polymers comprising peroxycarboxyl groups, wherein a suspension of a polymer comprising monoolefinically unsaturated dicarboxylic anhydride basic building blocks is mixed with hydrogen peroxide in an inert diluent.

Abstract: A composition comprising (A) polyvinyl alcohol having an amino group connected to a phenyl group and (B) at least one water resistance-imparting agent selected from polyepoxy compound, aldehyde compound, polyisocyanate compound, and water-soluble oxidizing agent; the composition exhibits outstanding water resistance even when used at room temperature; the composition finds use as a woodworking adhesive, plywood adhesive, and two-part instantaneously curing adhesive which does not require heating for curing.

Abstract: A crosslinking system which includes a 1,2,4-trioxacycloheptane and a crosslink-promoting polyfunctional ethylenically unsaturated compound. This system is employed in a process of crosslinking a thermoplastic polymer. Preferred polymers, useful in this process, include ethylene homopolymers and copolymers.

Abstract: Compositions of matter for use in oils and fuels are disclosed. The compositions arise from reaction products (C) formed by reacting substituted carboxylic acylating agents (A) with carboxylic reactants (B). The reactant (A) is usually a polyolefin substituted succinic anhydride or acid which is reacted with (B). (B) is usually a glyoxylic compound. Carboxylic reaction products (C) may further be reacted to form succinimide dispersants, esters or other derivatives. Products (C) may also be reacted with an .alpha.-.beta. unsaturated compound to form second carboxylic reaction products.

Abstract: A propylene resin composition obtained by dynamic heat treatment of a blend of (A) 100 parts by weight of a propylene-.alpha.-olefin block copolymer wherein a ratio (.eta..sub.1 /.eta..sub.2) of melt viscosity .eta..sub.1 at a shear rate of 10.sup.1 sec.sup.-1 to melt viscosity .eta..sub.2 at a shear rate of 10.sup.2 sec.sup.-1 is 3.5 to 8 as measured by a slit die method and (B)0.005 to 2 parts by weight of an organic peroxide, and having a melt flow rate (measured according to JIS K7210, at a temperature of 230.degree. C. under a load of 2.16 kg) adjusted to 50 to 300 g/10 minutes, a main endothermic peak temperature Tmp of 120.degree. to 150.degree. C. for melting temperature and a main exothermic peak temperature Tcp of 85.degree. to 105.degree. C. for crystallization temperature, as measured with a Differential Scanning Calorimetry, and a Tcp half-value width of 5.degree. C. or above, and a molded article obtained by using the same.

Abstract: This invention provides a method by which an alkylstyrene containing polymer may be exclusively functionalized at the primary benzylic carbon site of the styrenic monomer. The process of this invention comprises the treatment of an alkylstyrene containing polymer dissolved in a non-polar liquid medium with an organic hydroperoxide oxidizing reagent in the presence of a catalytically sufficient amount of a chromium compound, to oxidize a portion of the aromatic alkyl groups of the polymer to an oxygen containing functional group.

Abstract: This invention provides a method by which an alkylstyrene containing polymer may be exclusively functionalized at the primary benzylic carbon site of the styrenic monomer. The process of this invention comprises the treatment of an alkylstyrene containing polymer dissolved in a non-polar liquid medium with an organic hydroperoxide oxidizing reagent in the presence of a catalytically sufficient amount of a chromium compound, to oxidize a portion of the aromatic alkyl groups of the polymer to an oxygen containing functional group.

Abstract: This invention provides a method by which an alkylstyrene containing polymer may be exclusively functionalized at the primary benzylic carbon site of the styrenic monomer. The process of this invention comprises the treatment of an alkylstyrene containing polymer dissolved in a non-polar liquid medium with an organic hydroperoxide oxidizing reagent in the presence of a catalytically sufficient amount of a chromium compound, to oxidize a portion of the aromatic alkyl groups of the polymer to an oxygen containing functional group.

Abstract: A process for preparing polymers comprising peroxycarboxyl groups, wherein a suspension of a polymer comprising monoolefinically unsaturated dicarboxylic anhydride basic building blocks is mixed with hydrogen peroxide in an inert diluent.

Abstract: Interpenetrating polymer networks (IPN's), composed of polyisoprene (PI) and polyurethane (PU), together with a process for their preparation and their use in the manufacture of medical devices, such as catheters and catheter balloons, are disclosed. Both components are elastomers. The PI component is chemically crosslinked. The PU component is crystallizable and contains only physical crosslinks. The IPN's have glass transition temperatures in the range of from -65.degree. C. to -40.degree. C.

Abstract: Interpenetrating polymer networks (IPN's), composed of polyisoprene (PI) and polyurethane (PU), together with a process for their preparation and their use in the manufacture of medical devices, such as catheters and catheter balloons, are disclosed. Both components are elastomers. The PI component is chemically crosslinked. The PU component is crystallizable and contains only physical crosslinks. The IPN's have glass transition temperatures in the range of from -65.degree. C. to -40.degree. C.

Abstract: An apparatus and process for hydrogen peroxide vapor sterilization of medical instruments and similar devices make use of hydrogen peroxide vapor released from a substantially non-aqueous organic hydrogen peroxide complex, such as a urea-peroxide complex. Optionally, a plasma can be used in conjunction with the vapor. A method for preparing substantially non-aqueous hydrogen peroxide complexes is also provided. These complexes are useful as a source of peroxide vapor in hydrogen peroxide vapor sterilizers and as a component of self-sterilizing packaging materials.

Abstract: Blends of semi-crystalline polymers with rubbery thermoplastic copolymers are provided. The rubbery thermoplastic copolymers are elastic at temperatures above their Tg's and properties similar to thermoplastic elastomers and surface tensions 5 dynes/cm or more different, preferably greater than the surface tension of the semi-crystalline polymer. Improved properties include good elastic recovery, toughness, and high elasticity without significant loss in optical properties.

Abstract: Poly(monoperoxycarbonates) of the structure: ##STR1## where R, R.sup.1 and n are defined in the summary of the invention such as 1,1,1-tris(t-butylperoxycarbonyloxymethyl)ethane, intermediates for their preparation as well as processes for their preparation and use are disclosed. The monoperoxycarbonate compounds are useful in initiating the polymerization of ethylenically unsaturated monomers, particularly styrene, curing of unsaturated polyester resins, and in modifying the molecular weight of polymers such as by crosslinking or controlled chain degradation.