# Patent

## Title
Olefin polymerization process and products thereof

## Abstract

This application is a .sctn.371 national phase application of PCT/US97/02913 filed on Feb. 18, 1997, which takes priority from U.S. provisional application Ser. No. 60/012,131 filed on Feb. 23, 1996.

## Background
Precise macromolecular engineering using commodity monomers is becoming a major trend in polymer technology to satisfy the demand for new properties, improved cost effectiveness, ecology and quality. Functional polymers with low molecular weight, low polydispersity, compact, branched structures and terminally located reactive groups are expected to exhibit superior performance/cost characteristics, by virtue of lower inherent viscosity and higher reactivity vs. conventional linear statistical copolymers.

The terminally functional branched polymers appear to be ultimate reactive substrates for networks, because the branch points can substitute for a significant portion of expensive reactive groups and provide a better control of the reactive groups distribution. Particularly polymers having large numbers of short branches below critical molecular weight are unlikely to form any entanglements and should exhibit low inherent viscosity and good flow even in concentrated solutions.

Conventional techniques for sythesizing well defined branched polymers require expensive multistep processes involving isolation of reactive intermediate macromonomers. The macromonomers have polymerizable end groups, which are usually introduced using functional initiator, terminating or chain transfer agent. Well defined branched polymers are prepared by the macromonomer homopolymerization or copolymerization with suitable low molecular weight comonomer selected based on known reactivity ratios.

U.S. Pat. No. 4,680,352 describes molecular weight reduction and macromonomer (polymers or copolymers with unsaturated end-groups) synthesis in copolymerizations with acrylates and styrene with various Co(II) complexes.

J. Antonelli, et. al., U.S. Pat. No. 5,362,813 and C. Berge, et al., U.S. Pat. No. 5,362,826 disclose the preparation of macromonomers by radical addition-fragmentation processes and the copolymerization of macromonomers. Branched structures were not well characterized and the reincorporation of the branched macromonomers into more complex structures was not considered.

Dendrimers or hyperbranched polymers prepared using expensive, special multifunctional monomers or expensive multistep methods requiring repetitive isolation of the reactive intermediates have been reviewed by J. C. Salamone, ed., Polymeric Materials Encyclopedia, Vol.5 (1996).

The references cited above cover the copolymerization of vinyl monomers in the presence of chain transfer reagents, but do not disclose synthetic conditions for production of macromonomers or polymers containing branches upon branches.

This invention relates to a general process for the synthesis of addition polymers containing branches upon branches and having a polymerizable olefin end group by a convenient one-pot polymerization of selected vinyl monomers with chain polymerization initiators and a method to provide olefin end groups by chain transfer or termination agents. The polymerization is carried out in such a manner that chain transfer occurs frequently and each chain transfer event terminates that particular polymer chain with terminal polymerizable olefinic functionality. Subsequent reincorporation of the polymer chains produced early in the reaction leads to branching of subsequently-formed polymer chains which are terminated with polymerizable olefinic functionality. Subsequent reincorporation of the branched polymer chains leads to subsequently-formed polymer chains containing branches-upon-branches which are terminated with polymerizable olefinic functionality. Spontaneous repetition of the process leads to highly branched or hyperbranched products still retaining termini with polymerizable olefinic functionality.

This invention concerns an improved process for the free-radical polymerization of at least one unsaturated vinylic monomer to form a polymer whose molecular architecture includes branches upon branches and a polymerizable vinyl-terminated end group, comprising contacting, in the presence of a free-radical initiator:

wherein: CO.sub.2 H, COR, CO.sub.2 R, CN, CONH.sub.2, CONHR, CONR.sub.2 and R'; alkyl, substituted and unsubstituted aryl, substituted and unsubstituted heteroaryl, substituted and unsubstituted aralkyl, substituted and unsubstituted alkaryl, and substituted and unsubstituted organosilyl, the substituents being the same or different and selected from the group consisting of carboxylic acid, carboxylic ester, epoxy, hydroxyl, alkoxy, primary amino, secondary amino, tertiary amino, isocyanato, sulfonic acid and halogen, and the number of carbons in said alkyl groups is from 1 to 12; and unsubstituted aryl, substituted and unsubstituted heteroaryl, the substituents being the same or different and selected from the group consisting of carboxylic acid, carboxylic ester, epoxy, hydroxyl, alkoxy, primary amino, secondary amino, tertiary amino, isocyanato, sulfonic acid, substituted and unsubstituted alkyl, substituted and unsubstituted aryl, substituted and unsubstituted olefin and halogen; SnR.sub.3, halogen, R.sup.2 and R.sup.3 ; aralkyl, alkaryl and organosilicon groups wherein the substituent(s) are independently from the group carboxyl, epoxy, hydroxyl, alkoxy, amino and halogen; aryl, aralkyl, alkaryl and organosilicon groups wherein the substituent(s) are independently from the group carboxyl, epoxy, hydroxyl alkoxy, amino and halogen; of substituted and unsubstituted alkyl, cycloalkyl, aryl, aralkyl, alkaryl, organosilyl, alkoxyalkyl, alkoxyaryl, sulfate groups wherein the substituent(s) are independently selected from R, OR.sup.1, O.sub.2 CR, halogen, CO.sub.2 H and salts thereof, CO.sub.2 R, CN, CONH.sub.2, CO.sub.2 NHR, CONR.sub.2 ; of substituted and unsubstituted alkyl, cycloalkyl, aryl, aralkyl, alkaryl, organosilyl, alkoxyalkyl, alkoxyaryl, and P(O)R.sub.2 groups wherein the substituent(s) are independently selected from R, OR.sup.1, O.sub.2 CR, halogen, CO.sub.2 H and salts thereof, CO.sub.2 R, CN, CONH.sub.2, CO.sub.2 NHR, CONR.sub.2 ; the branch-upon-branch architecture and polymerizable vinylic chain termini, and a higher density of branches upon branches in that polymer by optimizing the polymerization in the following way: select step III and at least one of I; II; I and IV; and II and IV from steps: macromonomers and polymers toward 0; values of I, III and IV;

Based on the disclosure and Examples presented herein, one skilled in the art will be readily able to select the optimum ratio of (i)/(ii) for any given class of monomer(s) and values of (I), (III) and (IV) with minimum experimentation. One skilled in the art will also be able to select the appropriate chain transfer agent for the monomer(s) being polymerized, by reference to the well-known reactivity ratios of said chain transfer agents and monomer(s).

This invention further concerns the product of the above reaction which is composed primarily of a polymer having a branch-upon-branch structure and a polymerizable olefinic end group, having the structure: ##STR1## B"=X, B', H, CH.sub.3, CH.sub.2 CHR.sup.1 CH.sub.3, or CH.sub.2 CMeR.sup.2 CH.sub.3, R.sup.2 are as earlier defined.

We have discovered a general process for the synthesis of addition polymers containing branches upon branches and having a polymerizable vinylic end group by a convenient one-pot polymerization of selected vinyl monomers with chain polymerization initiators and a method to provide olefin end groups by chain transfer or termination agents. The polymerization is carried out in such a manner that chain transfer occurs frequently and that each chain transfer event terminates that particular polymer chain terminated with polymerizable olefinic functionality. The process is shown in Scheme 1. ##STR2## Subsequent reincorporation of the polymer chains produced early in the reaction leads to branching of subsequently-formed polymer chains which are terminated with polymerizable olefinic functionality. Subsequent reincorporation of the branched polymer chains leads to subsequently-formed polymer chains containing branches-upon-branches which are terminated with polymerizable olefinic functionality. Spontaneous repetition of the process leads to highly branched or hyperbranched products still retaining termini with polymerizable olefinic functionality.

The polymers made by the present process are useful in a wide variety of coatings. Other potential uses can include cast, blown, spun or sprayed applications in fiber, film, sheet, composite materials, multilayer coatings, photopolymerizable materials, photoresists, surface active agents, dispersants. adhesives, adhesion promoters, coupling agents, commpatibilizers and others. End products taking advantage of available characteristics can include, for example, automotive and architectural coatings or finishes, including high solids, aqueous or solvent based finishes. Polymers, such as those produced in this invention, would find use in, for example, structured polymers for use in pigment dispersants.

In a preferred process the free-radical initiator is selected from azo initiators, typical examples of which include: 2,2'-azobis(isobutyronitrile), VAZO-88=1,1'-azobis(cyclohexane-1-carbonitrile) (DuPont Co., Wilmington, Del.) VR-110=2,2'-azobis(2,4,4-trimethylpentane) (Wako Pure Chemical Industries, Ltd., Osaka, Japan) Chain transfer reagents, CH.sub.2 .dbd.CQ(CH.sub.2 --X), can be based upon vinylidene macromonomers prepared by several methods. A good example is the methyl methacrylate trimer, CH.sub.2 .dbd.C(CO2Me)--CH.sub.2 --CMe(CO2Me)--CH.sub.2 --CMe(CO2Me)--CH.sub.3. These radical addition-fragmentation chain transfer agents have been reviewed by E. Rizzardo, etal., Macromol. Symp. 98, 101 (1995).

Other organic chain transfer reagents include allylic sulfides, sulfones, bromides, phosphonates, stannanes, vinylidene terminated methacrylic oligomers, a-methyl styrene dimer and related compounds. Preferred chain transfer agents and polymerizable intermediate macromonomers exhibit dual reactivity, in that they can both undergo copolymerization or homopolymerization as well as promote competitive chain transfer through the addition-elimination process.

Substituent Q of the chain transfer reagent is chosen to convey the appropriate reactivity of the olefinic group in radical polymerization of the desired monomer(s) under polymerization conditions. The substituents Q and X can also be chosen so as to introduce any required end-group functionality into the polymer. Therefore using functional chain transfer agent (iii) can be a prefered method. These end groups can be the same or different and can be chosen such that the final polymer can be telechelic. Suitable end groups are particularly those compatible with free radical polymerization and include epoxy, hydroxyl, carboxyl, silyl.

The process can be potentially conducted by bulk, solution, suspension or emulsion polymerization using batch or preferably starved feed reactor, which offers better process control.

The treelike branched polymers are formed by in situ generation and copolymerization of first linear and subsequently increasingly branched macromonomers through the polymerizable olefin group. The method was demonstrated by model kinetic studies of monomer, chain transfer agent (CTA) conversions, polymer molecular weight increase combined with quantitative end group and branching characterization when reacting vinylidene MMA-trimer used as a CTA and butyl acrylate (BA) in a starved-feed reactor. Macromolecules typically with 2 to 30 branches each containing 5 to 20 monomers were prepared, branch length being primarily controlled by the monomer/chain transfer agent ratio, conversion and to some extend by temperature.

A chain polymerization is controlled by a chain transfer step so as to provide a polymerizable olefin end group (Scheme 1). The branch-upon-branch structure is built by in situ generation and copolymerization of linear and subsequently increasingly branched macromonomers through the polymerizable olefin group.

That monomer copolymerizability is primarily determined by the steric and electronic properties is well documented in the art. The chain process can involve either one or several different comonomers. Typical monomers include acrylates, methacrylates, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, styrene, a-methylstyrene, halogenated olefins, vinyl esters, but also can include N-vinyl carbazole, N-vinyl pyrrolidone, and dienes such as isoprene, and chloroprene.

Quantitative NMR analysis of the products, particularly end group structure and branching, combined with oligomer analysis by MALDI mass spectroscopy show that conventional radical termination and chain transfer processes can be effectively suppressed under these conditions, when acrylates (or styrene) are copolymerized with the vinylidene macromonomer/chain transfer agent. The polymer molecular weight and end group structure are predominantly controlled by the .beta.-scission chain transfer. High conversions (usually 80-90%) of the vinylidene end group are predominantly achieved by the incorporation, i.e., copolymerization leading to branches. The data are consistent with a mechanism, in which the initially formed branched macromolecules receive predominantly the vinylidene end group through the .beta.-scission chain transfer. Having a reactive vinylidene end group allows the singly-branched macromolecules to participate in analogous subsequent (secondary) copolymerization steps leading eventually to even more branched structures, which could be called branch-upon-branch polymers.

Formation of branch-upon-branch structures is indicated by the significant increase in the polymer molecular weight and in the number of branches per polymer molecule that occurs even at nearly complete conversion of the vinylidene (MMA).sub.3 .dbd., which was used as a chain transfer agent and model macromonomer and at high acrylate monomer conversions. The development of characterization methods for branched polymer formation from vinylidene macromonomers by NMR, SEC, GC, MALDI mass spectroscopy was essential for developing and confirmation of this method of making branch-upon-branch structures, see E. McCord, et al., ACS Polymer Prep. 36 (2), 106 (1995).

Branching density estimated from the ratio of grafting to .beta.-scission is primarily determined by the BA/chain transfer agent ratio, conversion and to some extend by temperature in the range 60 to 100.degree. C. Under standard conditions, one MMA-trimer branch occurs per 8 to 16 BA comonomers consumed, which corresponds to 1000-2,000 molecular weight of BA segment per one branch and is desirably below an entanglement length.

The copolymers were characterized by .sup.1 H and .sup.13 C NMR, by conventional SEC using RI detector vs. PMMA standards and compared with data obtained using universal calibration in THF and the light-scattering weight-average molecular weights. Under typical radical copolymerization conditions in starved feed reactor used in these studies, about a 10-fold molar excess of acrylate comonomer over methacrylate vinylidene macromonomer is required to achieve acceptable yield (>10%) and a significant number (>5) of branches per macromolecule. The number of 5 branches per molecule is a minimum (per definition) for branch-upon-branch structures.

Kinetic data at early and intermediate conversions showed as expected that .beta.-scission is favored over incorporation by higher temperatures. At almost complete vinylidene group conversion, the effect of temperature on the overall ratio of incorporation to .beta.-scission was found to be small. This is evidently due to somewhat higher activation energy of the competing .beta.-scission vs. the incorporation and due to the fact that incorporation is a major mechanism of the vinylidene group consumption.

Preferred monomers are:

Examples 1-15 Methacrylate Vinylidene Trimer (MMA).sub.3 .dbd. as Chain Transfer Agent and Macromonomer

This procedure illustrates the preparation, analysis and proof of the branch-upon-branch polymer architecture in which there are at least 5 branches in a starved feed reactor by a multi step/one pot process. Conditions of the branch-upon-branch structure formation are identified from the effects of temperature, monomer, chain transfer agent and initiator concentrations and conversion on the polymer structure. The broken line in each of the following Tables will indicate where significant levels of branch-upon-branch polymers are produced.

The polymers of this invention with the most desirable properties are those having at least 10%, more preferably at least 25%, and most preferably above 50%, branch upon branch architecture.

Polymerization of Butyl Acrylate with Vinylidene Methyl Methacrylate-Trimer as a Chain Transfer Agent and Macromonomer at 70.degree. C. Part      Ingredient         Amount ______________________________________ I         Toluene              8 g Decane               1 g (MMA).sub.3 =      7.5 g II        Toluene             25 g 2,2'-azobis(2-methylbutanenitrile) 1 g III       Butyl acrylate      32 g ______________________________________

Part I was charged into the reactor equipped with stirrer, reflux condenser, thermocouple, and nitrogen positive pressure, and heated to 70.degree. C. Part II and III were fed concurrently into the reactor over 150 and 120 minutes, respectively. After completing the addition of Part II, the reactor contents were held at 80.degree. C. for an additional 60 minutes. The copolymerization kinetics have been followed by gas chromatography, NMR and GPC. .about.5 g samples of the reaction mixture were withdrawn at 20 min. intervals followed by GC determination of the BA and vinylidene MMA-trimer concentrations. Volatiles were stripped on high vacuum for several hours and the oligomers/polymers were analyzed by NMR and GPC. Decane was used as an internal standard and molar response factors were determined using mixtures of known composition containing SCT MMA-trimer, BA and decane. The kinetic data are shown in Table 1. Polymer composition was followed by Matrix Assisted Laser Desorption Ionization (MALDI) Mass Spectroscopy. Polymer molecular weight was measured by SEC and viscometry. Structure of both polymers, including branching density and end groups, was characterized by .sup.1 H and .sup.13 C NMR. __________________________________________________________________________ CTA.sup.d Polymer Composition No. of Time conv. (mole %)  Br. Per Polymer       .eta..sup.d) (min) (%) (MMA).sub.3 MMA = BA Mol..sup.b) M.sub.n.sup.a) M.sub.n.sup.c) M.sub.n.sup.d) PD.sup.d) M.sub.n.sup.e) (dL/g) __________________________________________________________________________ 23 24.8 39.3 18.7 42.0 2.1 1200 1100 43 25.1 39.3 18.0 42.8 2.2 1300 1600 63 36.4 19.9 11.4 68.7 1.7 1600 2100 83 48.4 10.7 7.8 81.5 1.4 2100 2600 103 63.4 8.2 6.1 85.7 1.4 2500 3100 2400 2.4   0.055 120 75.5 7.3 3.8 88.9 1.9 3900 4300 3800 3.2   0.061 140 83.7 6.0 2.8 91.2 2.2 5200 6600 4400 3.6   0.070 181 93.8 5.7 1.4 92.9 4.0 9900 12200 7100 5.0   0.098 466 98.8 5.5 0.36 94.2 15.1   27000 25000 4.3   0.159 __________________________________________________________________________ .sup.a) (MMA).sup.3 = conversion by NMR .sup.b) No of Branches Per Molecule = (MMA).sup.3 in polymer/MMA = vinylidene ends in polymer .sup.c) by SEC vs. PMMA standards .sup.d) by SEC using universal calibration and viscometer .sup.e) by SEC using light scattering detector

Polymerization of Butyl Acrylate with Vinylidene Methyl Methacrylate-Trimer as a Chain Transfer Agent and Macromonomer at 70.degree. C. Part      Ingredient         Amount ______________________________________ I         Toluene              8 g Decane               1 g (MMA).sub.3 =      7.5 g II        Toluene             25 g 2,2'-azobis(2-methylbutanenitrile) 3 g III       Butyl acrylate      32 g ______________________________________

The procedure described in EXAMPLE 1 was followed except for the initiator concentration which was three times higher than that used in EXAMPLE 1. __________________________________________________________________________ CTA.sup.d Polymer Composition No. of Time conv. (mole %)  Br. Per Polymer        .eta..sup.d) (min) (%) (MMA).sub.3 MMA = BA Mol..sup.b) M.sub.n.sup.a) M.sub.n.sup.c) M.sub.n.sup.d) PD.sup.d) M.sub.n.sup.e) (dL/g) __________________________________________________________________________ 20 31.0 56.0 23.5 20.5 2.4  410 1200 40 36.6 49.5 9.9 40.5 5.0 2300 2100 60 46.8 24.5 13.0 62.5 1.9 1500 1800 80 62.8 14.5 8.0 77.6 1.8 2100 2600 100 88.1 12.0 2.7 85.3 4.5 5700 4200 123 96.7 6.6 1.0 92.4 6.7 14400 11500 143 99.1 5.2 0.36 94.4 14.5    25100 173 99.6 4.8 0.21 95.0 22.9    30200 360 99.8 4.9 0.16 94.9 30.6    29400 __________________________________________________________________________ .sup.a) (MMA).sub.3 = conversion by NMR .sup.b) No of Branches Per Molecule = (MMA).sub.3 in polymer/MMA = vinylidene ends in polymer .sup.c) by SEC vs PMMA standards .sup.d) by SEC using universal calibration and viscometer .sup.e) by SEC using light scattering detector

Polymerization of Butyl Acrylate with Vinylidene Methyl Methacrylate-Trimer as a Chain Transfer Agent and Macromonomer at 80.degree. C. Part      Ingredient         Amount ______________________________________ I         Toluene              8 g Decane               1 g (MMA).sub.3 =      7.5 g II        Toluene             25 g 2,2'-azobis(2-methylbutanenitrile) 1 g III       Butyl acrylate      32 g ______________________________________

The procedure described in EXAMPLE 1 was followed at 80.degree. C. Kinetic re shown in Table 3. __________________________________________________________________________ CTA.sup.a Polymer Composition No. of Time conv. (mole %)  Br. Per Polymer       .eta..sup.d) (min) (%) (MMA).sub.3 MMA = BA Mol..sup.b) M.sub.n.sup.a) M.sub.n.sup.c) M.sub.n.sup.d) PD.sup.d) M.sub.n.sup.e) (dL/g) __________________________________________________________________________ 20 13.3 48.2 26.0 25.8 1.9  980 1600 40 14.3 70.3 16.6 13.1 4.3 1700 1600 60 24.6 45.5 9.9 44.6 4.6 2300 1600 80 43.1 11.5 7.4 81.2 1.6 2200 2400 2100 1.3   0.028 100 83.9 6.7 3.5 89.8 1.9 4100 4100 3400 1.4   0.043 120 93.7 5.8 1.6 92.6 3.6 9000 9800 5500 1.9   0.058 140 98.2 5.7 0.74 93.5 7.7 18900 15000 5100 3.3   0.067 180 99.0 5.7 0.46 93.9 12.3    16600 5600 4.1   0.087 430 99.7 5.6 0.17 94.2 33.2    16100 6100 3.9   0.090 __________________________________________________________________________ .sup.a) (MMA).sub.3 = conversion by NMR .sup.b) No of Branches Per Molecule = (MMA).sub.3 in polymer/MMA = vinylidene ends in polymer .sup.c) by SEC vs. PMMA standards .sup.d) by SEC using universal calibration and viscometer .sup.e) by SEC using light scattering detector

Polymerization of Butyl Acrylate with Vinylidene Methyl Methacrylate-Trimer as a Chain Transfer Agent and Macromonomer at 90.degree. C. Part      Ingredient         Amount ______________________________________ I         Toluene              8 g Decane               1 g (MMA).sub.3 =      7.5 g II        Toluene             25 g 2,2'-azobis(2-methylbutanenitrile) 1 g III       Butyl acrylate      32 g ______________________________________

The procedure described in EXAMPLE 1 was followed at 90.degree. C. Kinetic re shown in Table 4. __________________________________________________________________________ CTA.sup.d Polymer Composition No. of Time conv. (mole %)  Br. Per Polymer         .eta..sup.d) (min) (%) (MMA).sub.3 MMA = BA Mol..sup.b) M.sub.n.sup.a) M.sub.n.sup.c) M.sub.n.sup.d) PD.sup.d) M.sub.n.sup.e) (dL/g) __________________________________________________________________________ 20 10.3 36.3 33.8 30.0 1.1  740 1100 40 30.7 12.0 25.7 62.4 0.5  750 1900 60 60.3 12.2 13.6 74.2 0.9 1300 2000 80 88.2 10.6 5.9 83.5 1.8 2700 3600 100 99.0 7.4 0.87 91.7 8.5 16400 16700 3,400 2.4    0.040 120 100 5.1 0.14 94.8 36.3    35500 9800 4.0 11000 0.132 145 100 3.2 0.12 96.7 26.3    25700 35500 4.0 22000 0.221 340 100 3.0 0.10 96.9 29.9    338000 __________________________________________________________________________ .sup.a) (MMA).sub.3 = conversion by NMR .sup.b) No of Branches Per Molecule (MMA).sub.3 in polymer/MMA = vinylidene ends in polymer .sup.c) by SEC vs. PMMA standards .sup.d) by SEC using universal calibration and viscometer .sup.e) by SEC using light scattering detector

Polymerization of Butyl Acrylate with Vinylidene Methyl Methacrylate-Trimer as a Chain Transfer Agent and Macromonomer at 100.degree. C. Part      Ingredient         Amount ______________________________________ I         Toluene              8 g Decane               1 g (MMA).sub.3 =      7.5 g II        Toluene             25 g 2,2'-azobis(2-methylbutanenitrile) 1 g III       Butyl acrylate      32 g ______________________________________

The procedure described in EXAMPLE 1 was followed at 100.degree. C. Kinetic are shown in Table 5. __________________________________________________________________________ CTA.sup.a Polymer Composition No. of Time conv. (mole %)  Br. Per Polymer        .eta..sup.d) (min) (%) (MMA).sub.3 MMA = BA Mol..sup.b) M.sub.n.sup.a) M.sub.n.sup.c) M.sub.n.sup.d) PD.sup.d) M.sub.n.sup.e) (dL/g) __________________________________________________________________________ 20 21.7 16.4 28.1 55.6 0.6  730 1200 40 57.4 15.1 14.0 70.9 0.9 1200 1500 60 85.7 11.0 7.2 81.8 1.5 2200 2600 80 97.5 9.6 2.1 88.3 4.5 6900 4100 100 99.5 7.2 0.46 92.3 15.7 31000 13200 10500 4.3   0.078 120 99.8 5.5 0.20 94.3 27.6    15400 16300 3.7   0.125 142 99.6 5.0 0.15 94.9 33.0    15500 15400 3.7   0.118 175 99.0 5.0 0.16 94.9 31.0    13700 12300 4.2   0.114 310 99.4 5.0 0.11 94.9 45.0    20400 __________________________________________________________________________ .sup.a) (MMA).sub.3 = conversion by NMR .sup.b) No of branches Per Molecule = (MMA).sub.3 in polymer/MMA = vinylidene ends in polymer .sup.c) by SEC vs. PMMA standards .sup.d) by SEC using universal calibration and viscometer .sup.e) by SEC using light scattering detector __________________________________________________________________________ Effect of Temperature and the Ratio of Butyl Acrylate/Vinylidene Methyl Methacrylate Trimer on Number of Branches Per Macromolecule. Number of Branches (MMA).sub.3 = Per Molecule Temp (mole %)       .sup.13 C NMR M.sub.n EXAMPLE (.degree. C.) .sup.1 H NMR .sup.13 C NMR .sup.1 H NMR EG.sup.b) QC.sup.c) .sup.1 H NMR .sup.13 C NMR SEC.sup.a) __________________________________________________________________________ Control 80 15.0 14.7 2.2  2.2 --  2,800 2,400 2,300 6     80 9.6  9.6  6.6  5.7 5.0 11,500 10,000 9,100 Control 80 18.3 17.5 1.9  1.8 1.8 2,500 2,400 3,200 7     80 9.1  8.8  7.7  6.7 7.2 13,700 12,200 10,700 8     100 8.7  8.1  11.5 6.4 9.8 20,600 12,200 8,200 9     60 9.7  8.9  5.9  5.5 5.9 10,300 9,800 11,900 10    60 7.1  10.1 6.1  -- -- 10,800 --   9,200 __________________________________________________________________________ .sup.a) by SEC in THF, M.sub.n vs. PMMA .times. 128/100 [M(BA)/M(MMA) .sup.b) EG  from end group analysis, the ratio of [1/3 of the total methy ester carbons minus (the average of the 2 vinyl carbons and the unsaturated carbonyl carbon from the bscission end group)] to [the averag of the 2 vinyl carbons and the unsaturated carbonyl carbon from the bscission end group .sup.c) QC  from quarternary carbon analysis, the ratio of [the integral of the quarternary carbon of the branch] to [the average of the 2 vinyl carbons and the unsaturated carbonyl carbon from the bscission end group __________________________________________________________________________ Effect of Temperature and the Ratio of Butyl Acrylate/Vinylidene Methyl Methacrylate Trimer on Number of Branches Per Macromolecule. (MMA).sub.3 = Number of Branches Experiment (mole %)  Per Molecule M.sub.n (temp.) .sup.1 H NMR .sup.13 C NMR .sup.1 H NMR .sup.13 C NMR .sup.1 H NMR .sup.13 C NMR SEC.sup.a) __________________________________________________________________________ 11 (80.degree. C.) 7.5  7.4  17   --   33,600 --   20,200 Control (80.degree. C.) 14.8 14.4 3.7  3.5   4,900 4,800 3700 12 (80.degree. C.) 8.2  7.6  23   --   41,700 --   28,200 13 (100.degree. C.) 7.3  7.2  27   --   --   --   21,600 14 (60.degree. C.) 8.2  7.1  13   --   25,000 --   27,600 15 (60.degree. C.) 7.5  7.9  56   --   107,000 --   64,100 __________________________________________________________________________ .sup.a) from universal calibration Methyl Methacrylate Vinylidene Trimer (MMA).sub.3 .dbd. as Chain Transfer Agent and Macromonomer

Linear poly(butyl acrylates) have an "a" coefficient of 0.70 in the Mark-Houwink equation, [.eta.]=K M.sup.a. Copolymers 3 in contrast have an "a" Mark-Houwink coefficient of 0.35-0.50, as would be expected for a polymer having a branched rather than a linear structure.

## Claims

1. An improved process for the free-radical polymerization of at least one unsaturated vinylic monomer to form a polymer whose molecular architecture includes at least 10% having branches upon branches and a polymerizable vinyl-terminated end group, comprising contacting wherein: CO.sub.2 H, COR, CO.sub.2 R, CN, CONH.sub.2, CONHR, CONR.sub.2 and R'; percent of the (i) has Z=H; alkyl, substituted and unsubstituted aryl, substituted and unsubstituted heteroaryl, substituted and unsubstituted aralkyl, substituted and unsubstituted alkaryl, and substituted and unsubstituted organosilyl, the substituents being the same or different and selected from the group consisting of carboxylic acid, carboxylic ester, epoxy, hydroxyl, alkoxy, primary amino, secondary amino, tertiary amino, isocyanato, sulfonic acid and halogen, and the number of carbons in said alkyl groups is from 1 to 12; and unsubstituted aryl, substituted and unsubstituted heteroaryl, the substituents being the same or different and selected from the group consisting of carboxylic acid, carboxylic ester, epoxy, hydroxyl, alkoxy, primary amino, secondary amino, tertiary amino, isocyanato, sulfonic acid, substituted and unsubstituted alkyl, substituted and unsubstituted aryl, substituted and unsubstituted olefin and halogen; SnR.sub.3, halogen, R.sup.2 and R.sup.3 ; aralkyl, alkaryl and organosilicon groups wherein the substituent(s) are independently from the group carboxyl, epoxy, hydroxyl, alkoxy, amino and halogen; aryl, aralkyl, alkaryl and organosilicon groups wherein the substituent(s) are independently from the group carboxyl, epoxy, hydroxyl, alkoxy, amino and halogen; of substituted and unsubstituted alkyl, cycloalkyl, aryl, aralkyl, alkaryl, organosilyl, alkoxyalkyl, alkoxyaryl, sulfate groups wherein the substituent(s) are independently selected from R, OR.sup.1, O.sub.2 CR, halogen, CO.sub.2 H and salts thereof, CO.sub.2 R, CN, CONH.sub.2, CO.sub.2 NHR, CONR.sub.2 ; of substituted and unsubstituted alkyl, cycloalkyl, aryl, aralkyl, alkaryl, organosilyl, alkoxyalkyl, alkoxyaryl, and P(O)R.sub.2 groups wherein the substituent(s) are independently selected from R, OR.sup.1, O.sub.2 CR, halogen, CO.sub.2 H and salts thereof, CO.sub.2 R, CN, CONH.sub.2, CO.sub.2 NHR, CONR.sub.2 ; the branch-upon-branch architecture and polymerizable vinylic chain termini, and a higher density of branches upon branches in that polymer by optimizing the polymerization in the following way: select step III and at least one of I; II; I and IV; and II and IV from steps: macromonomers and polymers toward 0; values of I, III and IV;

2. A process according to claim 1 wherein Z=H.

3. A process according to claim 1 wherein X=.paren open-st.CUY--CH.sub.2).sub.n --Z'.

4. A process according to claim 1 wherein, in (i), Z=H and, in (ii), X=.paren open-st.CUY--CH.sub.2).sub.n --Z'.

5. A process according to claim 1 wherein Z' is substituted alkyl, aryl, aralkyl, alkaryl, organosilyl wherein the reactive substituent(s) are independently selected from the group carboxylic acid, carboxylic ester, epoxy, hydroxyl, alkoxy, amino and halogen.

6. A process according to claim 3 wherein: of each of (i) and (ii) is 85 to 100%.

7. A composition of matter comprising a polymer having a branch-upon-branch structure and a polymerizable olefinic end group, having the structure: ##STR3## B"=X, B', H, CH.sub.3, CH.sub.2 CHR.sup.1 CH.sub.3, or CH.sub.2 CMeR.sup.2 CH.sub.3, SnR.sub.3, halogen, R.sup.2 and R.sup.3, where Z' is selected from H, SR.sup.1, S(O)R, S(O).sub.2 R, R.sup.2 and R.sup.3 ; CO.sub.2 H, COR, CO.sub.2 R, CN, CONH.sub.2, CONHR, CONR.sub.2 and R', where: unsubstituted aryl, substituted and unsubstituted heteroaryl, the substituents being the same or different and selected from the group consisting of carboxyl acid, carboxylic ester, epoxy, hydroxyl, alkoxy, primary amino, secondary amino, tertiary amino, isocyanato, sulfonic acid, substituted and unsubstituted alkyl, substituted and unsubstituted aryl, substituted and unsubstituted olefin and halogen; aryl, aralkyl, alkaryl and organosilicon groups wherein the substituent(s) are independently from the group carboxyl, epoxy, hydroxyl, alkoxy, amino and halogen; of substituted and unsubstituted alkyl, cycloalkyl, aryl, aralkyl, alkaryl, organosilyl, alkoxyalkyl, alkoxyaryl, sulfate groups wherein the substituent(s) are independently selected from R, OR.sup.1, O.sub.2 CR, halogen, CO.sub.2 H and salts thereof, CO.sub.2 R, CN, CONH.sub.2, CO.sub.2 NHR, CONR.sub.2 ; of substituted and unsubstituted alkyl, cycloalkyl, aryl, aralkyl, alkaryl, organosilyl, alkoxyalkyl, alkoxyaryl, and P(O)R.sub.2 groups wherein the substituent(s) are independently selected from R, OR.sup.1, O.sub.2 CR, halogen, CO.sub.2 H and salt thereof, CO.sub.2 R, CN, CONH.sub.2, CO.sub.2 NHR, CONR.sub.2 ;

8. The composition according to claim 7 wherein X is --(CUY--CH.sub.2).sub.n --Z' where U is selected from H and R.