Homopolymerization maleic anhydride

B De Roover, J Devaux, R Legras. Maleic anhydride homopolymerization during melt functionalization of isotatic polypropylene. J Polymer Sci Polymer Chem 34 1195-1202, 1996. 

Write structural formulas for maleic anhydride (M ) and stilbene (M2). Neither of these monomers homopolymerize to any significant extent, presumably owing to steric effects. These monomers form a copolymer,... 

The radical-catalyzed polymerization of furan and maleic anhydride has been reported to yield a 1 1 furan-maleic anhydride copolymer (89,91). The stmcture of the equimolar product, as shown by nmr analyses, is that of an unsaturated alternating copolymer (18) arising through homopolymerization of the intermediate excited donor—acceptor complex (91,92). 

The use of monomers that do not homopolymerize, eg, maleic anhydride and dialkyl maleates, reduces the shock sensitivity of tert-huty peroxyesters and other organic peroxides, presumably by acting as radical scavengers, that prevent self-accelerating, induced decomposition (246). 

The polymerization of alkyl vinyl ethers is of some commercial importance. The homopolymers, which can be obtained only by cationic polymerization, are useful as plasticizers of other polymers, adhesives, and coatings. (The copolymerization of vinyl ethers with acrylates, vinyl acetate, maleic anhydride, and other monomers is achieved by radical polymerization but not the homopolymerizations of alkyl vinyl ethers.)... 

The patterns of reactivity parameters, like the Q-e parameters, can be used to analyze reactivity in both copolymerization and homopolymerization. Look at the data in Table 6-4 and compare with the parameters in Table 6-8. The highly reactive radicals are those with lower values of ns- The highly reactive monomers are those with the more positive or less negative values of v. However, v is not the only consideration, polarity is also important. For example, maleic anhydride is a monomer with one of the most positive v values, but it undergoes facile copolymerization only with monomers with which it has a polarity difference. This is the alternation tendency and is given by... 

Some monomers with no tendency toward homopolymerization are found to have some (not high) activity in copolymerization. This behavior is found in cationic copolymerizations of tetrahydropyran, 1,3-dioxane, and 1,4-dioxane with 3,3-bis(chloromethyl)oxetane [Dreyfuss and Dreyfuss, 1969]. These monomers are formally similar in their unusual copolymerization behavior to the radical copolymerization behavior of sterically hindered monomers such as maleic anhydride, stilbene, and diethyl fumarate (Sec. 6-3b-3), but not for the same reason. The copolymerizability of these otherwise unreactive monomers is probably a consequence of the unstable nature of their propagating centers. Consider the copolymerization in which M2 is the cyclic monomer with no tendency to homopolymerize. In homopolymerization, the propagation-depropagation equilibrium for M2 is completely toward... 

Preparation of addition polymers having the oxolene (dihydrofuran) functionality can be envisioned to occur in two possible ways (Scheme 13). Both, in fact, have been observed (77MI11102). Whereas furan (53) or its derivatives do not homopolymerize under free radical conditions, 1 1 alternating copolymers possessing the 1,4-structure are produced with maleic anhydride (50). Intermediate formation of a CT complex between monomers (50) and (53) is believed to be necessary before polymerization can occur. On the other hand, cationic polymerization is quite facile. The outcome is straightforward with benzo[f>]furan derivatives, producing 1,2-polymers. Optically active poly(benzofurans) are formed when the cationic polymerizations are conducted in the presence of a chiral anion. 

The property of the polymers in question to form nonspherical nanostructures was confirmed in experimental studies. Shih et al. [29] synthesized alternating copolymers of 1-alkenes with maleic anhydride. The maleic anhydride units were hydrolyzed to maleic acid units. Fully hydrolyzed macromolecules associated into microstructures of cylindrical and ellipselike shape. The cylindrical shape was characteristic of copolymers with octadecene and hexadecene moieties, while the copolymers with lower alkene copolymers (tetradecene, dodecene, decene, octene) formed ellipsoidal structures. Wataoka et al. [30] investigated the formation of nonspherical helices in a system of maltopentaose-carrying polystyrene (PS). The polymer was synthesized via the homopolymerization of vinylbenzyl maltopentaose amide (Scheme 3). 

N. G. Gaylord and J. Y. Koo, Participation of Cationic Intermediates in Radical-induced Homopolymerization of Maleic Anhydride, J. Polym. Sci. Polym Lett. Ed., 19,107-112 (1981). 

Spontaneous 1 1 copolymerization has been noted when sulfur dioxide was bubbled through bicycloheptene at —40°C. (88), when isobutylene was bubbled through methyl a-cyanoacrylate (54), when 1,3-dioxole was mixed with maleic anhydride (17), and when vinylidene cyanide was mixed with styrene (20), the latter reactions at room temperature. None of these monomers undergoes homopolymerization under the same experi-... 

Similarly, whereas the Diels-Alder reaction is accelerated at elevated temperatures, under polymerization conditions, the reaction of isoprene and maleic anhydride is extremely exothermic, and the relative amounts of adduct and copolymer are temperature dependent. It has been reported (81) that the rate of copolymerization is very fast compared with the rate of homopolymerization of the diene or the dienophile, and the energy of activation is approximately 5 kcal./mole. Although the rate of copolymerization increases at elevated temperatures, the simultaneous adduct formation which also occurs more readily at elevated temperatures limits the maximum rate to lower temperatures. 

Reactivity of a monomer in chain-growth copolymerization cannot be predicted from its behavior in homopolymerization. Thus, vinyl acetate polymerizes about twenty times as fast as styrene in a free radical reaction, but the product is almost pure polystyrene if an attempt is made to copolymerize the two monomers under the same conditions. Similarly, addition of a few percent of styrene to a polymerizing vinyl acetate mixture will stop the reaction of the latter monomer. By contrast, maleic anhydride will normally not homopoly merize in a free-radical system under conditions where it forms one-to-one copolymers with styrene. 

The reactivity of a polar monomer can be considerably enhanced in copolymerization with a species of the opposite polarity. Maleic anhydride does not homopolymerize under normal free-radical reaction conditions but it forms 1 1 copolymers with styrene under the same conditions and even reacts with stilbene (7-6), which itself will not homopoloymerize. 

Alfrey and Goldfinger (24) have shown that eqs. (7) cannot be employed if the system contains one or more components that cannot homopolymerize resp. add to a growing chain ending in a monomer unit of their own type, e.g. diethyl maleate, maleic anhydride, crotonic acid, sywm-dichlorethylene if monomer is of such type, and all the... 

The reaction of a conjugated diene such as butadiene or iso-prene and an electron acceptor monomer such as maleic anhydride proceeds through a ground state complex which undergoes cycliza-tion to yield the Diels-Alder adduct. However, under UV light, in air or in the presence of sensitizers, the adduct is accompanied by the equimolar, alternating copolymer which results from excitation of the ground state complex, followed by homopolymerization of the excited complex (13)> as shown in Eq. (I8). 

If the excited ethylene dimer exists as an ion radical pair, propagation may incorporate both monomeric units of the dimer, analogous to the behavior of comonomer charge transfer complexes such as butadiene-maleic anhydride, or only one unit, as noted in the homopolymerization of N-vinylcarbazole in the presence of electron accepting monomers such as acrylonitrile and maleic anhydride. 

Although long considered incapable of homopolymerization, maleic anhydride is readily polymerized under UV irradiation in the presence of a photosensitizer (lB,19). The polymerization presumably involves propagation of excited maleic anhydride ( ). It is noteworthy that the structure of poly(maleic anhydride) contains fused cyclopentanone and succinic anhydride units, derived from two interacting maleic anhydride units. This suggests that propagation involves excited dimer rather than monomer. 

Ethylene and maleic anhydride undergo peroxide-induced homopolymerization under similar conditions, i.e. in the presence of peroxides undergoing rapid decomposition, presumably through the propagation of excited monomers or dimers. 

The formation of block copolymers can result from the addition of excess styrene monomer to SMA macroradicals (13). Maleic anhydride has also been reported to homopolymerize when initiated by gamma-radlation of free radical Initiators. The highest conversions were obtained employing acetic anhydride as the solvent, in a ratio of solvent to monomer of 75 25 (14,15). 

The distinction suggested by the terms "reactive mononer and "unreactive monomer is not supported by the results obtained in the homopolymerization of styrene and of maleic anhydride (MAH) in the presence of a peroxyester undergoing rapid decomposition. Thus, the addition of 0.5 mmole di-sec-butyl peroxydicarbonate (t.. 1.3 hr) in 4 portions at 2 min intervals (total reaction... 

The following sections detail the literature reports pertaining to the synthesis of block copolymers using nitroxide-mediated polymerization techniques. The sections are organized according to monomer type and generally follow the historical development of the particular subsection. Most literature on nitroxide mediated preparation of block copolymers is found for the styrene-based monomers, and is summarized first. This is followed by acrylates and dienes, as they were the next monomers to be studied. These sections are followed by more recent work with vinyl pyridine, acrylamides, and maleic anhydride. The final section deals with methacrylates. This is presented last to stress the importance of developing new nitroxides that can successfully be used for the homopolymerization of methacrylate-based monomers. 

Since the Arimoto/Haven report of vinylferrocene polymerization was not detailed, this monomer was made and both its homopolymerization and its copolymerization were studied with a variety of organic comonomers such as styrene, methylacrylate, maleic anhydride, acrylonitrile, methyl methacrylate, N-vinylpyrolidone, vinyl acetate, and so on.31-38 The polymers were as well characterized as possible, and copolymer compositions were obtained versus feed mole ratios. 

New macroradicals have been obtained by proper solvent selection for the homopolymerization of styrene, methyl methacrylate, ethyl acrylate, acrylonitrile, and vinyl acetate, and by the copolymerization of maleic anhydride with vinyl acetate, vinyl isobutyl ether, or methyl methacrylate. These macroradicals and those prepared by the addition to them of other monomers were stable provided they were insoluble in the solvent. Since it does not add to maleic anhydride chain ends, acrylonitrile formed a block copolymer with only half of the styrene-maleic anhydride macroradicals. However, this monomer gave excellent yields of block polymer when it was added to a macroradical obtained by the addition of limited quantities of styrene to the original macroradical. Because of poor diffusion, styrene did not add to acrylonitrile macroradicals, but block copolymers formed when an equimolar mixture of styrene and maleic anhydride was added. 

The radical catalyzed homopolymerization of the furan-maleic anhydride (F-MAH) Diels-Alder adduct yields a saturated homopoly-mer at temperatures below 60 C, and an unsaturated equimolar alternating copolymer at elevated temperatures, due to retrograde dissociation of the adduct (10, 11). The copolymerization of monomeric furan and maleic anhydride yields the same unsaturated alternating copolymer, independent of temperature (1C)). 

In contrast, the radical catalyzed homopolymerization of the cyclopentadiene-maleic anhydride (CPD-MAH) Diels-Alder adduct yields a saturated homopolymer at temperatures as high as 220 C, while retrograde dissociation occurs at even higher temperatures. Nevertheless, the copolymerization of monomeric cyclopentadiene and maleic anhydride yields a saturated 1 2 copolymer (12-15). 

The homopolymerization of the endo and exo adducts was carried out in the melt at 150 to 260 C and in chlorobenzene at 120°C (Table I). Polymer was obtained when the catalyst was used at a temperature where the half-life was short, e.g. less than 2 hr, conditions shown to be effective in the homopolymerization of maleic anhydride (16), norbornene (17, 18) and 5-norbornene-2,3-di-carboxylic anhydride (CPD-MAH adduct) (12-15), as well as the... 

It has previously been proposed that the saturated products from the homopolymerization of norbornene (17) and the CPD-MAH Diels-Alder adduct (12-15), and probably from the furan-maleic anhydride Diels-Alder adduct (11), have rearranged structures. An analogous structure would arise from the homopolymerization of the cyclopentadiene-N-phenylmaleimide CPD-NPMI adduct, as follows ... 

The principle of cyclopolymerization has been applied to the synthesis of macrocyclic ether-containing polymers which may simulate the properties of crown ethers. l,2-Bis(ethenyloxy)benzene (a 1,7-diene) and l,2-bis(2-ethenyloxyethoxy)benzene (a 1,13-diene) are typical of the monomers synthesized. Homopolymerization of the 1,7-diene via radical and cationic initiation led to cyclopolymers of different ring sizes homopolymerization of the 1,13-diene led to cyclic polymer only via cationic initiation. Both monomer types were copolymerized with maleic anhydride to yield predominantly alternating copolymers having macro-cyclic ether-containing rings in the polymer backbone. 

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