WO1991000300A1

WO1991000300A1 - (CO)POLYMER MODIFICATION EMPLOYING UNSATURATED t-ALKYL PEROXY ALKENES

Info

Publication number: WO1991000300A1
Application number: PCT/EP1990/001041
Authority: WO
Inventors: Jerney Jelenic; John Meijer
Original assignee: Akzo N.V.
Priority date: 1989-06-28
Filing date: 1990-06-27
Publication date: 1991-01-10

Abstract

Novel organic unsaturated tertiary alkyl peroxy alkenes are disclosed and a process of modifying (co)polymers employing these peroxy alkenes is also disclosed. (Co)polymers are modified by contacting them with one or more of these organic peroxides and decomposing the peroxide. By this process the physical properties of the (co)polymers, such as adhesion to polar substrates and lap shear strength, can be enhanced. According to a preferred embodiment, the modification reaction is carried out in the presence of a coagent whereby the advantageous polymer properties, such as adhesion to polar materials, are further enhanced. Also disclosed are shaped objects manufactured using the modified (co)polymers prepared by the process of the present invention.

Description

(Co)polymer Modification Employing Unsaturated t-Alkyl Peroxy Alkenes

The invention relates to compounds useful in modifying (co)polymers, a process for modifying (co) polymers with these compounds, and to shaped objects comprising the modified (co) polymers.

It is generally known that the introduction of epoxide or other functional groups into the appropriate (co)polymers may lead to improved physical and chemical properties of the (co) polymers. According to Rubber World 191(6), pp. 15-20 (1985) and Rubber Developments, Vol. 38, No. 2, pp. 48-50 (1985), for instance, the introduction of epoxide groups into natural rubber leads to advantages such as an increased glass transition temperature, increased oil resistance, reduced gas permeability, improved resilience, increased tensile strength and improved adhesion to other materials, such as silica fillers, glass fibers and other polymers such as PVC. Further, the polymers thus modified can be subjected to chemical reactions that are typical of epoxy groups. As examples thereof may be mentioned: i) cross-linking the polymer with polyfunctional compounds containing active hydrogen atoms, such as polyamines and dibasic acids, which is described in Chemical Reactions of Polymers, E.M. Fettes (ed.), Interscience Publications, New York (1964), chapter II, part E, pp. 152 et. seq., ii) covalently bonding antioxidants having amino groups to the polymer, which is described in Journal of Polymer Science, Polymer Letters Edition, Vol. 22, pp. 327-334 (1984) and iii) reacting the polymer with fluorine-containing compounds, such as trifluoroacetic acid, resulting in a polymer with improved lubricity and ozone resistance, which is described in WO 85/03477.

Generally, epoxide groups are introduced into (co) polymers by so-called epoxidation reactions, in which an unsaturated (co)polymer in the form of a latex or dissolved in an organic solvent, is brought into contact with an epoxidizing reagent suitable for reacting with unsaturation present in the (co)polymer. An example of such compounds are the lower aliphatic carboxylic acids. This method, however, are the lower aliphatic carboxylic acids. This method, however, suffers from several disadvantages. First, the requirement that the (co)polymer be unsaturated significantly limits the number of (co)polymers that can be epoxidized by this method. For example, saturated polymers such as polypropylene cannot be functionalized using this method.

Secondly, the use of solvents in the epoxidation reaction necessitates a subsequent purification step for residual solvent removal. Such a purification step is disadvantageous from a polymer processing standpoint since it adds an additional, costly processing step. Further, disposal of solvents is becoming an increasing concern because of the environmental hazards these solvents create. Thirdly, this type of epoxidation reaction is always accompanied by undesirable side reactions, such as the formation of hydroxyl groups, acyloxy groups, ether groups, keto groups and aldehyde groups. These side reactions cause numerous problems when such epoxidation reactions are employed.

It is also known to prepare epoxide group-containing (co)polymers by copolymerization and graft copolymerization reactions with monomers containing a glycidyl group (cf. Journal of Polymer Science, Vol. 61, pp. 185-194 (1962), Makromol . Chem., Rapid Commun. 7, pp. 143-148 (1986) and Die Angewandte Makromol ecu! are Chemie 48, pp. 135-143 (1975)). The inevitable accompanying formation of undesirable side products, such as the formation of homopolymers of the glycidyl group-containing monomer, is a significant drawback to the practice of this method. Moreover, this method only permits preparation of a limited group of modified (co)polymers.

Bull. Soc. Chim. France No. 2, 198-202 (1985) discloses t-butyl allyl peroxide and its use for epoxypropanating organic solvents with labile hydrogen atoms. As solvents are mentioned cyclohexane, tetrahydrofuran, propionic acid, propionic anhydride, methyl propionate, acetonitrile and chloroform.

European Patent Application 0 273 990 (Akzo) discloses the use of certain unsaturated organic peroxides in the preparation of epoxide groups-containing (co)polymers. These compounds have been shown to be effective in introducing epoxide groups onto (co)polymers. However, this patent application does not disclose the compounds of the present invention. More particularly, the peroxides of the present invention are significantly different than those of European Patent Application 0 273 880 since they contain additional carbon units between the peroxy functionality and the unsaturation. This is an important distinction since it leads to a different rearrangement of the peroxide free radical than is set forth in EP 0 273 990. In the present case the rearranged peroxy radical will include acyclic ether having at least three carbon atoms which will impart different properties to the modified (co)polymer.

The present inventi on has for its object the elimination of the drawbacks of the prior art. In addition, the present invention is also useful in introducing cyclic carbonate or ketone functionalities onto polymers instead of, or in addition to, cyclic ether functionalities. As a result, the modified polymers made by the present invention are useful in a wider variety of applications. For these purposes, the present invention provides novel organic peroxides useful for the modification of (co)polymers. The organic peroxides are compounds of the following formula:

wherein R₁ and R₂ are H or C_1-4 alkyl; R₃ is H, C_1-4 alkyl or an electron withdrawing group; n=2-5; m=1-3; p and q are 0 or 1 with the proviso that when n=2, one of p or q is 0 and with the further proviso that when p=0, q=1; and when m=1, R= a tertiary alkyl group optionally substituted with a hydroxyl group and containing 4-18 carbon atoms, p-menth-8-yl or a group of the general formula:

wherein k = 0, 1 or 2 and R₇ is an isopropenyl group, a 2-hydroxyisopropyl group, or an isopropyl group;

when m = 2, R= an alkylene group having 8-12 carbon atoms and a tertiary structure at both ends thereof, an alkynylene group having 8-12 carbon atoms and a tertiary structure at both ends thereof, or a group of the general formula:

wherein j = 0 or 1 and R₇ has the above-indicated meaning; and when m = 3, R= 1,2,4-triisopropylbenzene-α,α',α"-triyl or 1,3,5-triisopropylbenzene-α,α',α"-triyl.

The alkyl, alkenyl and alkylene groups may be linear or branched, unless otherwise indicated. The present i nventi on al so rel ates to a process for the modi fi cati on of (co) polymers by contacti ng them wi th an organi c peroxi de of the fol l owi ng formul a:

wherein R₁ and R₂ are H or C_1-4 alkyl; R3 is H, C_1-4 alkyl or an electron withdrawing group; n=2-5; m=1-3; p and q are 0 or 1; and when m=1, R= a tertiary alkyl group optionally substituted with a hydroxyl group and containing 4-18 carbon atoms, p-menth-8-yl or a group of the general formula:

The alkyl, alkenyl and alkylene groups may be linear or branched, unless otherwise indicated.

The present invention also relates to articles of manufacture comprising one or more (co)polmers modified by the process of the present invention. More particularly, the (co)polymers modified by the process of the present are excellently suited for the manufacture of shaped objects.

Some of the compounds within the formula II are known in the prior art from EP 0 225 102 and EP 0 178 141. These published European Patent applications disclose the compound of the formula II when n=2, p=1 and q=1. These patents disclose the production of carbonate-containing copolymers from t-butyl allyl peroxycarbonate which are useful as a compatibilizing agent in a polymer blend of a polyolefin and styrene, as an emulsifying agent in a high polymer emulsion and as an adhesive at the interface of a polyolefin and a styrene polymer. These carbonate-containing copolymers, however, are produced by copolymerizing the unsaturated t-butyl allyl peroxycarbonate with other monomers. Thus, the polymer modification process of the present invention is not disclosed in these published European Patent Applications. Published Japanese Patent Application J6 3057-567-A discloses tertiary alkyl allyl peroxycarbonate esters which are useful in the production of functional polymers by copolymerization with other ethylenic olefins. The copolymers are useful in accelerating graft copolymerization. However, the polymer modification process of the present invention is not disclosed in this publication.

Finally, Germany patent application DT 2631-911 discloses unsaturated carbonate and carbamate peroxides which are useful and vulcanizing and cross-linking agents for polymers such as polyethylene, ethylene-propylene rubber, and many other rubbers, polyester resins, and ethyl ene-vinyl acetate copolymers.

Generally, the synthetic routes for making the tertiary alkyl peroxy alkenyl carbonates used in the process of the present invention are known in the art from EP 0 178 141 and EP 0 225 102, the disclosures of which are hereby incorporated by reference. The preferred mode of synthesizing the tertiary alkyl peroxy alkenyl carbonates is to react the appropriate tertiary alkyl hydroperoxide with an unsaturated chloroformate, separate the organic layer and subsequently wash this material to provide the desired product in relatively pure form.

Suitable tertiary alkyl hydroperoxides useful in this synthesis process include t-butyl hydroperoxide, t-pentyl hydroperoxide, t-octyl hydroperoxide and t-hexyl hydroperoxide, among others. Suitable unsaturated chloroformates include 3-butenyl chloroformate, 4-pentenyl chloroformate, 3-pentenyl-chloroformate, 4-hexenyl chloroformate, and 5-hexenyl chloroformate, among others. The tertiary alkyl peroxy alkenes where m=1 can be synthesized by reacting the appropriate t-alkyl hydroperoxide with an unsaturated bromide or an unsaturated mesylate. Suitable unsaturated bromides include buten-3-yl bromide, penten-4-yl bromide, penten-3-yl bromide, hexen-4-yl bromide, 4-methyl-penten-3-yl bromide, 5-methyl-hexen-4-yl bromide, and hexen-5-yl bromide, among others. Suitable unsaturated mesylates include buten-3-yl mesylate, penten-3-yl mesylate, 4-methyl-penten-3-yl mesylate, and 3-methyl-buten-3-yl mesylate. The tertiary alkyl peroxy alkenes and alkenyl carbonates where m=2 or 3 can be synthesized by reacting a suitable dihydroperoxy alkane with an unsaturated bromide for the alkenes or a chloroformate for the alkenylcarbonates, in an organic solvent in the presence of a base. Suitable dihydroperoxy alkanes include, but are not limited to, 2,5-dimethyl-2,5-dihydroperoxy hexane and

2,7-dimethyl-2,7-dihydroperoxy octane. Suitable bases include pyridine, sodium hydroxide, and potassium hydroxide, among others.

Typical examples of tertiary alkyl peroxy alkenes according to the invention include t-butyl peroxy-3-methyl butene-3, t-pentyl-4-pentenyl peroxide, t-butyl-4-pentenyl peroxide, t-butyl-3-butenyl peroxide, t-pentyl-5-hexenyl peroxide, t-pentyl-3-butenyl peroxide, t-pentyl-4-pentenyl peroxide, t-octyl-3-butenyl peroxide, t-octylperoxy-3-methylbutene-3, t-butyl-5-hexenyl peroxide, t-butyl-3-pentenyl peroxide, t-butylperoxy-4-methylpentene-4; t-butyl peroxy-4-pentenyl carbonate; t-butyl peroxy-3-butenyl carbonate;

2,5-bis(peroxy-3-butenylcarbonate) 2,5-dimethylhexane; t-pentyl peroxy-3-butenyl carbonate; t-butyl peroxy-5-hexenyl carbonate; t-butyl peroxy-3-pentenyl carbonate; t-octylperoxy-3-butenyl carbonate; and 2,7-bis(peroxy-3-butenyl carbonate) 2,5-dimethyl octane.

The peroxides can be prepared, transported, stored and applied as such or in the form of powders, granules, solutions, aqueous suspensions, emulsions or pastes. Other forms may also be useful in specific circumstances.

Which of these forms is to be preferred partly depends on the ease of feeding the peroxide into closed systems. Also, considerations of safety may play a role to the extent that desensitizing agents may have to be incorporated in certain compositions to ensure their safety. As examples of suitable desensitizing agents may be mentioned solid carrier materials such as silica, chalk and clay, inert plasticizers or solvents such as mono- or dichlorobenzene, and water.

The present t-alkylperoxy alkenes are exceptionally well suited for use in the preparation of cyclic ether, cyclic carbonate and/or ketone groups-containing (co) polymers, in which process a non-modified (co)polymer is brought into contact with the t-alkylperoxy alkenes in order to cause modification of the (co)polymer. Cyclic ether groups containing 3 or more carbon atoms are introduced onto the (co)colymer.

The peroxy alkenes may be brought into contact with the (co) polymer in various ways, depending upon the particular object of the modification process. For example, if surface modification of a three dimensional polymeric object is desired, the t-alkylperoxy alkenes may simply be applied to the surface of the material to be modified. Alternatively, it is often desirable to distribute functional groups homogeneously througout the (co)polymeric matrix. In this instance, the t-alkylperoxy alkenes may be mixed with the material to be modified, which material may be in the molten state, in the form of a solution, or, in the case of an elastomer, in a plastic state. To accomplish homogeneous mixing of the material to be modified and the t-alkylperoxy alkenes, most conventional mixing apparatus may be used. Typical mixing apparatus includes kneaders, internal mixers and (mixing) extruding equipment. Should mixing be a problem for a particular material because of its high melting point, for example, the (co)polymer can first be provided with functional groups on its surface while in the solid state and subsequently melted and mixed to distribute the functional groups througout the material. Alternatively, the (co)polymer may be first dissolved and the reaction with the present t-alkylperoxy alkenes can then be carried out in solution. An important practical aspect of the present invention is that the moment the t-alkylperoxy alkene and the (co) polymer are brought into contact with each other and also the moment that the t-alkylperoxy alkene is to react with the (co)polymer can be chosen independently of the other usual polymer processing steps, including the introduction of additives, shaping, etc. For instance, the modification may be done before other additives are introduced into the polymer or after the introduction of other additives. More importantly, it is possible to accomplish the present polymer modification during a polymer shaping step such as extrusion, compression moulding, blow moulding or injection moulding. The sole restriction applies to polymers which are to be cross-linked. In that case the t-alkylperoxy alkene should be contacted with the (co)polymer prior to cross-linking.

Examples of suitable (co)polymers which according to the present invention can be modified to include cyclic ether or other types of functional groups such as carbonate groups, for example, are saturated (co)polymers such as polyethylene, e.g. LLDPE, MDPE, LDPE, and HDPE, polypropylene, both isotactic and atactic, ethylene/vinyl acetate copolymer, ethylene/ethylacrylate copolymer,

ethylene/methylmethacrylate copolymer, ethylene/methacrylate copolymer, chlorinated polyethylene, fluorrubber, silicone rubber, polyurethane, polysulphide, polyacrylate rubber, ethyl ene/propylene copolymer, phoyphenylene oxides, nylon, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polycarbonates, copolyetheresters, poly(butene-1), poly(butene-2), poly(isobutene), poly(methylpentene), polyvinyl chloride/acrylonitrile graft copolymer, and combinations thereof. Unsaturated (co)polymers may also be modified by the t-alkyl peroxy alkenes of the present invention. Suitable unsaturated (co)polymers include polybutadiene, polyisoprene, poly(cyclopentadiene), poly(methylcyclopentadiene), partly dehydrochloridated polyvinyl chloride, butadiene/styrene copolymer, acrylonitrile/butadiene/styrene terpolymer,

ethylene/propylene/dienemonomer terpolymer, isoprene/styrene copolymer, isoprene/isobutylene copolymer, isoprene/styrene/acrylonitrile terpolymer, polychloroprene, butadiene/acrylonitrile copolymer, natural rubber, and combinations thereof. Also, combinations of saturated and unsaturated polymers can be modified in accordance with the present invention. In general, any (co) polymer comprising abstractable hydrogen atoms can be modified by the present process.

It has been found that when certain (co)polymers are contacted with the present peroxy alkenes, some degradation of the polymer chains may occur. This degradation may affect the mechanical properties of the modified (co)polymer. Those polymers which are prone to formation of tertiary carbon radicals under the conditions of free radical reactions tend to undergo degradation. For instance, polymers which tend to degrade include polyisobutylene, poly(α-methyl)-styrene, polymethacrylates, polymethacrylamide, polyvinylidene chloride, polypropylene and particularly isotactic polypropylene, and polyvinyl alcohol. According to a preferred embodiment of the present invention, the modification process is conducted in the presence of a coagent in order to reduce or prevent the negative effects of polymer degradation or enhance the degree of modification of the (co)polymer.

A coagent is generally understood to be a polyfunctional reactive additive such as a polyunsaturated compound which will react rapidly with polymer radicals, will overcome steric hindrance effects and will minimize undesirable side reactions. Further information about coagents (which are sometimes called coactivators) is set forth in Rubber Chemistry and Technology, Vol. 61, pp. 238-254 and W. Hofmann, Progress in Rubber and Plastics Technology, Vol. 1, No. 2, March 1985, pp. 18-50, the disclosures of which are hereby incorporated by reference. In relation to the present invention the term "coagent" has the same meaning as given in these publications.

A wide variety of useful coagents are commercially available including di- and triallyl compounds, di-and tri(meth)acrylate compounds, bismaleimide compounds, divinyl benzene, vinyl toluene, vinyl pyridine, parachinone dioxime, 1,2-cis-polybutadiene and their derivatives. Furthermore, other useful coagents also include oligomers of 1,3-diisopropenyl benzene, 1,4-diisopropenyl benzene, and 1,3,5-triisopropenyl benzene.

The incorporation of an effective amount of one or more of these coagents into the (co)polymer prior to or during the reaction with the present peroxy alkenes will tend to reduce or prevent the degradation of the modified materials and thereby maintain the mechanical properties at the same level or better. Suprisingly, in some cases the coagent may result in improved mechanical properties such as an enhanced adhesion strength in modified (co)polymers of a polar nature. Thes enhancement may be attributable to a greater degree of functional group introduction into the (co) polymer resulting from the presence of a coagent.

It may be preferable to modify polymers less liable to undergo degradation in the presence of coagents due to the greater amount of functional groups which can be introduced into the modified (co)polymer with the same quantity of peroxy alkene, in this manner. Such polymers, which are typically those that are cross-linked when contacted with peroxides, include polyethylene, atactic polypropylene, polystyrene, polyacrylates, polyacrylamides, polyvinylchloride, polyamides, aliphatic polyesters, polyvinyl pyrrol i done, unsaturated rubbers, polysiloxanes, ethylene/propylene rubbers,

ethylene/propyl ene/diene rubbers and their copolymers.

As a result of the present invention, the extremely useful physical and chemical properties resulting from the presence of cyclic ether, cyclic carbonate and/or ketone groups on the (co)polymers, can now be obtained with an extremely large group of (co)polymers. The introduction of carbonate functionalities onto polymers is particularly useful for producing polyhydroxy or other types of polyurethanes without employing isocyanates such as is described in U.S. patent no. 3,084,140 and "Polyurethane Elastomers Obtained Without the Use of Diisocyanates," Rappoport, L.Ya. et al., International Polymer Science and Technology, 8, No. 1, 1981, the disclosures of which are hereby incorporated by reference. In addition, further uses of cyclic carbonate-containing polymers are detailed in U.S. patent 2,935,494, the disclosure of which is also hereby incorporated by reference. The most preferred (co) polymers for modification by the compounds of the present invention are polyethylene, polypropylene, ethyl ene/propylene copolymer, ethyl ene/vinyl acetate copolymer, and ethyl ene/propylene/dienemonomer terpolymer. The peroxy alkene of the present invention is generally used in an amount of 0.01 to 15% by weight, preferably 0.1 to 10% by weight, and most preferably 1.0 to 5.0% by weight, calculated on the basis of the weight of the (co)polymer. Mixtures of the peroxy alkenes according to the invention may also be employed. In addition, in certain situations it may be advantageous to use an auxiliary free radical generator which has a decomposition temperature lower than that of the peroxy alkene.

The (co)polymers modified in accordance with the present invention are useful for their standard applications although particular useful properties can be improved by the process of the present invention. In particular, due to the increased adhesion provided by the modification process, these modified (co)polymers are well suited for the fabrication of shaped objects. Further, these (co)polymers can be used in blends with other modified (co)polymers or with unmodified (co) polymers. For example, modified ethyl ene/propylene rubbers may be blended with unmodified nylon to significantly improve the impact strength of the nylon composition. The modification process itself, is generally carried out at temperatures in the range of 50°C to 250°C, and preferably from 100ºC to 200°C, care being taken that the duration of the modification reaction under the given conditions is at least several half-life periods of the peroxy alkenylcarbonate.

As mentioned above, the (co)polymer may also contain the usual polymer additives. As examples of such additives may be mentioned: stabilizers such as inhibitors of oxidative, thermal or ultraviolet degradation, lubricants, extender oils, pH controlling substances such as calcium carbonate, release agents, colorants, reinforcing or non-reinforcing fillers such as silica, clay, chalk, carbon black and fibrous materials, nucleating agents, plasticizers, accelerators, and cross-linking agents such as peroxides and sulfur. These additives may be employed in the usual amounts.

The invention is further described in the following examples.

Example 1 Preparation of t-Butyl Peroxy-3-Butenyl Carbonate

To a stirred mixture of 0.21 moles of t-butylhydroperoxide (70% w/w) and 0.175 moles of 3-butenyl chloroformate (95% w/w) was added 0.245 moles of a potassium hydroxide solution (25% w/w) over a period of 30 minutes at a temperature of 15-20°C. Stirring was continued for another 60 minutes at 15-20°C. The organic layer was then separated and subsequently washed with 30 grams of an aqueous potassium hydroxide solution (10% w/w) over a period of 5 minutes at 15-20°C; 25 grams of an aqueous solution of Na₂S₂O3 together with 20 grams of an NaAc/HAc buffer and 20 grams of water over a period of 10 minutes and stirring was continued for an additional 15 minutes all at a temperature of 15-20°C; 30 grams of an aqueous solution of NaCl (5% w/w) over 5 minutes at 15-20°C twice; and 30 grams of an aqueous solution of NaHC03 (5% w/w) over 5 minutes at 15-20°C. After drying the organic layer with magnesium sulfate, 28.5 grams of a colorless liquid was obtained having a peroxide content of 95.6% corresponding to a yield of 87%. The structure of the peroxide was confirmed by NMR and IR spectroscopic analysis.

Example 2

Preparation of t-Butyl Peroxy-4-Pentenyl Carbonate The same procedure as in example 1 was carried out except that 4-pentenyl chloroformate was substituted for 3-butenyl chloroformate. A colorless liquid solution was obtained having a peroxide content of 94.7% corresponding to a yield of 93%. The structure of the product was confirmed by NMR and IR spectroscopic analysis.

Example 3

Preparation of 2,5-bis(Peroxy-3-Butenyl Carbonate)-2,5-Dimethylhexane To a stirred mixture of 125 ml of diethylether, 0.625 moles of pyridine and 0.25 moles of 2,5-dimethyl -2,5-dihydroperoxy hexane (98% w/w) was added 0.64 mole of 3-butenyl chloroformate (95% w/w) over a period of 50 minutes at 5-10°C. Stirring was continued for an additional period of 270 minutes at 5-10°C. Thereafter, 100 grams of water was added to the reaction mixture at 5-10°C and the organic layer was separated. The organic layer was subsequently washed with 75 grams of 2 Normal HCl over 5 minutes at 5-10°C; 50 grams of an aqueous solution of potassium hydroxide (2.5% w/w) over 5 minutes at 10°C four times sequentially; and 75 grams of an aqueous solution of NaCl (25% w/w) over 5 minutes at 10°C. The organic layer was then dried with magnesium sulfate and the solvent was removed under a reduced presssure of 0.8 mbar at 10°C. 85 grams of a viscous liquid was obtained having a peroxide content of 86.2% corresponding to a yield of 78.3%. The structure of the peroxide was confirmed by NMR and IR spectroscopic analysis. Exampl e 4

Preparation of t-Butyl-4-Pentenyl Peroxide To a stirred mixture of 0.25 mole of penten-4-yl bromide (97% w/w), 0.50 mole of t-butyl hydroperoxide (70% w/w) and 0.05 mole of tetrabutylammonium bromide (99% w/w) was added 0.50 mole of potassium hydroxide (45% w/w) over a period of 10 minutes at 20/25°C. Stirring was continued for an additional period of 210 minutes at 20-25°C. Thereafter, 50 ml of water and 150 ml of pentane were added to the reaction mixture at 20°C. The organic layer was separated and subsequently washed with 75 ml of an aqueous solution of potassium hydroxide (10% w/w) over 5 minutes at 20 °C four times sequentially; and 75 ml of water over 5 minutes at 20°C six times sequentially. After drying the organic layer with magnesium sulfate the solvent was removed under a reduced pressure of 10 mbar at 20°C. 38.5 grams of a colorless liquid was obtained having a peroxide content of 95.7% corresponding to a yield of 93%. The structure of the peroxide was confirmed by NMR and IR spectroscopic analysis.

Example 5

Preparation of t-Butyl-3-Butenyl Peroxide The same procedure as described in example 4 was employed to prepare t-butyl-3-butenyl peroxide except that buten-3-yl bromide was used. A colorless liquied was obtained having a peroxide content of 94.7% corresponding to a yield of 95%. The structure of the peroxide was confirmed by NMR and IR spectroscopic analysis. Exampl e 6_

Preparation of t-Butyl Peroxy 3-Methyl Butene-3 The same procedure as described in example 4 was employed to prepare t-butyl peroxy 3-methyl butene-3 except that instead of employing penten-4-yl bromide, the fol l owi ng compound was used as the starti ng materi al :

A colorless liquid was obtained having a peroxide content of 96.6%, corresponding to a yield ot 82%. The structure of the peroxide was confirmed by NMR and IR spectroscopic analysis.

Example 7. Modification of Low Density Polyethylene

Polyethylene in powder form (Lacqtene 1070 MN 040) is mixed with peroxy alkene. A Haake Rheocord System 40 fitted with an electrically heated roller mixer chamber type Rheomix 600 is employed to carry out the modification reaction. The mill is operated at 30 rpm (friction 3:2), a ram pressure of 60 kPa, and the reaction is carried out over a period of one hour. A modified low density polyethylene polymer is obtained. The amount of peroxy alkene, polymer, the reaction temperatures, the torque analysis and the physical properties of the modified polyethylene are listed in Table 1.

A sample of each modified polymer was compressed into a plate 1 mm thick over a period of 15 minutes, and at a temperature of 160°C. Subsequently, the peel strength of a bi-component lacquer and the lap shear strength using an epoxy resin were measured. The 180° peel strength was determined according to ASTM-D 429-81 using a Zwick® Tensile tester 1474 at 25 mm/min. Besides indicating the nature of the failure, the peel strength is reported by this method as (average peel force)/(diameter of test pieces).

The lap shear strength was measured using an epoxy resin of the following composition: 10 g. of bisphenol A/F epoxy resins (Epikote® DX 235, ex. Shell), 6 g. of polyaminoamide (Epilink^® 177, ex. Akzo Chemicals) and 0.08 g. of silan® A 174 (ex. Union Carbide). A thin film of resin was applied to the adhesion surface area (20x15 mm) of a modified polymer plate (40×20×1 mm). Another modified polymer plate was placed on the adhesion surface area and the two parts were firmly clamped together to avoid occlusion of air. This composition was kept in a stove for 72 hours at 30°C.

The lap shear strength was determined on a Zwick^® tensile tester 1474 by measuring the force (kg/cm²) needed to separate the plates from each other at a speed of 25 mm/min. If the adhesion fails by shifting apart of the two pieces of polymer, the measured force is a measure for adhesion of the epoxy resin. If the polymer breaks before the adhesion fails the force at which the adhesion will fail is not measurable but it will be at least higher than the force required for polymer breakage. This example shows that polyethylene, when modified by the process of the present invention, exhibits improved physical properties including adhesion and lap shear strength. The ability to improve these physical properties by employing the simple and inexpensive process of the present invention provides a wide range of possibilities for improving the suitability of polymeric materials for their present applications as well as adapting these polymeric materials to new and different applications. Table 1

Reference t-butylperoxy t-butylperoxy 2,5-bis(peroxy-3- t-butylperoxy- t-butyl-3 t-butyl-4

Standard 4-pentenyl3-butenylbutenylcarbonate) 3-methylbutenyl pentenyl

carbonate carbonate 2,5-dimethyl butene-3 peroxide peroxide hexane

Amount of Lacqtene 1070 MN040(g) 100 100 100 100 100 100 100 Amount of Modifying additive (g) - - 4.16 3.94 4.34 3.28 3.05 3.31Millequivalents of Modifying Additive - - 20 20 20 20 20 20

Torque analysis

M_min (Nm) 5.1 8.1 7.4 7.1 4.3 4.2 4.5 time till M_min (min) 60 1.2 1.4 1.6 3.0 3.0 1.8

ΔM (Nm) 0 11.9 13.4 14.8 1.1 1.1 3.3 time till M_max (min) - - 7.0 9.2 8.0 12.6 11.6 9.8

M₆₀: torque after 60 min (Nm) 5.1 10.2 12.6 15.7 4.2 4.0 7.1

Temperature analysi s

temp, at M_min (°C) 131 118 118 118 145 144 139 temp, at M_max (°C) - - 138 137 135 152 151 152 max. temp, reached = T_max (°C) - - 138 138 139 154 152 154 time till T_max (min) - - 7.0 98 49.2 12.6 15.8 31.6 temp, end reaction (°C) 131 133 135 137 148 151 154

Physical Properties

Adhesion-PUR l acquer(10^-2×N/mm) 0.8 5.2 5.2 5.8 1.2 1.2 0.9 Lap Shear Strength (MPa × 10^-2) 13 17 24 23 12 19 13

Exampl e 8

Modification of Polypropylene

Polypropylene (Hostalen PPU 0810P) is mixed with two different peroxy alkenes of the present invention. A Haake Rheocord System 40 fitted with an electrically heated roller mixer chamber type Rheomix 600 is employed to carry out the modification reaction. The mill is operated at 300 r.p.m. (friction 3:2), and a ram pressure of 60 kPa, and the reaction is carried out over a period of fifteen minutes. A modified polypropylene polymer is obtained. The lap shear strength of the modified polypropylene is shown is table 2. Table 2

Reference t-butyIperoxy-3- t-butyl-3-bute¬

Standard methyl butene-3 nyl-peroxide Lap Shear Strength

(MPa×10^-2) 22 > 87 67

The foregoing description and examples of the invention were presented for the purpose of illustration and description only and are not to be construed as limiting the invention in any way. Accordingly, the scope of the invention is to be defined by the claims appended hereto.

Claims

What is claimed is:

1. An organic peroxide of the general formula:

wherein R₁ and R₂ are H or C_1-4 alkyl; R3 is H, C1-4 alkyl or an electron withdrawing group; n=2-5; m=1-3; p and q are 0 or 1 with the proviso that when n=2, one of p or q is 0 and with the further proviso that when p=0, q=1; and when m=1, R= a tertiary alkyl group optionally substituted with a hydroxyl group and containing 4-18 carbon atoms, p-menth-8-yl or a group of the general formula:

2. An organic peroxide according to claim 1, characterized in that at least one of p or q is 1.

3. An organic peroxide according to claim 1, characterized in that the peroxide is selected from the group consisting of t-butyl peroxy3- methyl butene-3, t-pentyl-4-pentenyl peroxide, t-butyl-4-pentenyl peroxide, t-butyl-3-butenyl peroxide, t-butyl peroxy-4-pentenyl carbonate, t-butyl peroxy-3-butenyl carbonate, 2,5 bis(peroxy3butenylcarbonate)2,5-dimethylhexane, t-pentyl-5-hexenyl peroxide, t-pentyl peroxy-3-butenyl carbonate,

t-octylperoxy-5-propyl hexene-5 and t-nonyl

peroxy-3-methyl-3-butenyl carbonate.

4. A process for the preparation of a modified (co)polymer by using an organic peroxide, said process comprising the step of contacting a peroxide of the formula:

wherein R₁ and R_{2 are} H or C_1-4 alkyl; R3 is H, C1-4 alkyl or an electron withdrawing group; n=2-5; m=1-3; p and q are 0 or 1; and when m=1, R= a tertiary alkyl group optionally substituted with a hydroxyl group and containing 4-18 carbon atoms, p-menth-8-yl or a group of the general formula:

wherein k = 0 , 1 or 2 and R₇ is an isopropenyl group, a 2-hydroxyisopropyl group, or an isopropyl group;

when m = 2, R= an alkyl ene group having 8-12 carbon atoms and a tertiary structure at both ends thereof, an alkynylene group having 8-12 carbon atoms and a tertiary structure at both ends thereof, or a group of the general formula:

wherein j = 0 or 1 and R₇ has the above-indicated meaning; and when m = 3, R= 1,2,4-triisopropylbenzene-α,α',α"-triyl or 1,3,5-triisopropylbenzene-α,α',α"-triyl; with a (co)polymer whereby the peroxide is decomposed and the (co)polymer is modified.

5. A process in accordance with claim 4, characterized in that at least one of p or q is 1.

6. A process according to claim 4, characterized in that the peroxide is selected from the group consisting of t-butylperoxy-3-methyl butene-3, t-pentyl-4-pentenyl peroxide, t-butyl-4-pentenyl peroxide, t-butyl-3-butenyl peroxide, t-butyl peroxy-4-pentenyl carbonate, t-butyl peroxy-3-butenyl carbonate, 2,5 bis(peroxy-3-butenylcarbonate)2,5-dimethylhexane,

t-pentyl-5-hexenyl peroxide, t-pentyl peroxy-3-butenyl carbonate, t-octylperoxy-5-propyl hexene-5 and t-nonyl

peroxy-3-methyl-3-butenyl carbonate.

7. A process according to any one of claims 4-6, characterized in that the amount of peroxide that is contacted with the (co)polymer is 0.01 to 15% by weight of the (co)polymer, the reaction temperature is from 50-250°C, and the duration of the modification step is at least five half-life periods of the peroxide.

8. A process according to claim 7, characterized in that the added amount of peroxide is 0.1 to 10% by weight of the (co)polymer and the reaction temperature is from 100-200°C.

9. A process according to any one of claims 4-8, further characterized in that the peroxide is contacted with the (co)polymer in the presence of a coagent.

10. A process according to claim 9, wherein the coagent is selected from the group consisting of di- and triallyl compounds, di- and tri-(meth)acrylate compounds, bismaleimide compounds, divinyl compounds, polyalkenylbenzenes and their polymers, vinyl toluene, vinyl pyridine, parachinone dioxime, polybutadiene and their derivatives.

11. A process according to one of claims 4-10, characterized in that the (co)polymer is selected from the group consisting of polyethylene, polypropylene, ethylene/propylene copolymer, ethylene/vinylacetate copolymer, ethylene/propyl ene/dienemonomer terpolymer, 2,6-dimethylpolyphenyleneoxide, and mixtures thereof.

12. A process according to any one of claims 4-11, characterized in that the (co) polymer is degraded during the modification step.

13. A process according to any one of claims 4-11, characterized in that the (co)polymer is cross-linked during the modification step.

14. A shaped object manufactured using a (co)polymer prepared by the process according to any one of claims 4-13.

15. A shaped object manufactured using two or more (co)polymers, of which at least one is a (co)polymer prepared by the process according to any one of claims 4-13.