Polymerization of vinylcyclopropanes. V. Radical copolymerization of 1, 1-dichloro-2-vinylcyclopropane with monosubstituted ethylenes

A peculiar copolymer composition equation applicable to the radical copolymerization of 1,1-dichloro-2-vinylcyclopropane with monosubstituted ethylenes was developed. The theory was applied to such ethylenes as methyl acrylate, methyl methacrylate, and styrene. The reactivity ratio parameters which give the best fit to the experimental data were determined.     

Studies on the copolymerization of unsaturated 1,3-dioxane derivatives—IV. Radical copolymerization of 2-furyl-5,5-dimethyl-1,3-dioxane with maleic anhydride

The copolymerization of 2-furyl-5,5-dimethyl-1,3-dioxane with maleic anhydride in the presence of a radical catalyst yields equimolar, alternating copolymers in which the furyl units have 2,5-linkage. It has been shown that 2-furyl-5,5-dimethyl-1,3-dioxane forms a charge transfer complex with maleic anhydride. The equilibrium constant for the complex was determined by NMR spectroscopy.     

Alternating copolymerization of ethylene with maleic anhydride

The copolymerization of ethylene with maleic anhydride was carried out with γ-radiation and a radical initiator, i.e., 2,2′-azobisisobutyronitrile and diisopropyl peroxydicarbonate under pressure at various reaction conditions. The homopolymerization of neither monomer was observed in this system. In the γ-ray-initiated copolymerization the G value (polymerized monomer molecules per 100 e.v.) was shown to be between 10³ and 10⁴. It was found that the dose rate exponent of the rate is approximately unity, and the rate is proportional to the amount of ethylene monomer. Apparent activation energies of 1.8 and 27.5 kcal./mole were obtained for γ-ray-initiated and AIBN-initiated copolymerization, respectively. Since the composition of copolymer is independent of monomer molar ratio and the molar ratio of ethylene to maleic anhydride in the polymer is approximately unity, the monomer reactivity ratios were obtained as r_E ? 0 and r_M ? 0 for γ-ray-initiated polymerization at 40°C. Alternating copolymerization was, therefore, concluded to occur. Infrared analysis of the copolymer is almost consistent with this. The copolymer in the solid state is amorphous. It is soluble in water, cyclohexane, and dimethylformamide and insoluble in lower alcohols, ether, and aromatic hydrocarbons. The aqueous solution of polymer gave a strong acid.     

Alternating copolymerization of maleic anhydride with allyl chloroacetate

Some regularities of radical alternating copolymerization of maleic anhydride with allyl chloroacetate are studied. The formation of donor–acceptor complexes between comonomers with complexing constant K_c = 0.052 L/mol is found using ¹H NMR spectroscopy. The kinetic parameters for this copolymerization reaction are found and the quantitative contribution of monomer complexes to chain-growth radical reactions is calculated. It is shown that either a “free-monomer” mechanism (dilute solutions) or a “mixed” mechanism (concentrated solutions) prevails for chain growth during radical copolymerization depending on total monomer concentration. It is found that inhibition of degradative chain transfer in the course of the reaction studied takes place owing to the presence of α-chlorine atom in the allyl chloracetate molecule and formation of charge transfer complex.     

Radical copolymerization of the C9 hydrocarbon fraction of liquid pyrolysis products with maleic anhydride

Radical copolymerization of the C₉ hydrocarbon fraction of liquid pyrolysis products with maleic anhydride was studied. The influence of reaction conditions on the copolymer yield, its molecular mass, and maleic anhydride content was elucidated. Hydrophilic products showing promise as modifying additives to paper stock, binding agents, dispersants, and compatibilizers were prepared.     

Laser-Initiated copolymerization of N-vinylpyrrolidone with maleic anhydride and maleimide

This article describes the laser-initiated copolymerization of N-vinylpyrrolidone with maleic anhydride and maleimide via charge transfer complexes. The dependence of copolymer yield on the molar ratios of the monomers in the feed and on the irradiation time is described. Based on the ultraviolet and infrared spectroscopy, and chemical analysis results, a tentative mechanism of polymerization is suggested. The rates of polymerization of several monomer systems are compared. The N-vinylpyrrolidone and maleimide system shows the highest rate of polymerization.     

Complex radical copolymerization of di-n-butylstannyl dimethacrylate with maleic anhydride

Mechanisms of radical copolymerization of di-n-butylstannyl dimethacrylate with maleic anhydride in the presence of 2,2-asobisisobutyronitrile are discussed. Complexing (K_eq) and copolymerization (r₁ and r₂) constants have been determined. Quantitative contributions of cyclization and complexing to reactivity ratios of the monomers under study and to propagation reactions have been estimated. The copolymerization has been found to proceed predominantly at the complex radical cyclocopolymerization step, leading to cyclized and linear unsaturated units in the macromolecule chain.     

Free radical copolymerization of methyl substituted stilbenes with maleic anhydride

Stilbene-maleic anhydride is a well-known donor-acceptor comonomer pair which undergoes free radical copolymerization to form an alternating copolymer. A series of methyl substituted stilbenes were synthesized and copolymerized with maleic anhydride. A conversion versus time study was undertaken to understand the methyl substituent effect on copolymerization rates. Methyl substituents on the phenyl ring of stilbene can change the reactivity of stilbene by changing the resonance stability of the propagating radical and steric hindrance in the propagation step and thereby change the copolymerization rate. Methyl substituted stilbene-maleic anhydride copolymers were determined by quantitative ¹³C 1D NMR to be alternating copolymers. Size exclusion chromatography (SEC) measurements showed that the weight-average molecular weights of these copolymers varied from 3000 to over 1,000,000 g/mol. Interchain aggregation was observed in poly((E)-4-methylstilbene-alt-maleic anhydride) by dynamic light scattering (DLS). The SEC trace for poly((E)-4-methylstilbene-alt-maleic anhydride) exhibited bimodal peaks. No glass transition temperature or crystalline melting temperature was observed between 0 °C and 250 °C by differential scanning calorimetry (DSC). Thermogravimetric analysis (TGA) showed that these polymers have 5% weight loss around 290 °C.     

Spontaneous copolymerization of 4-methylene-1,3-dioxolanes with maleic anhydride

The copolymerization of methylenedioxolanes, such as 4-methylene-1,3-dioxolane (I) and 2,2-dimethyl-4-methylene-1,3-dioxolane (II), with maleic anhydride (Manh) gives rise spontaneously to the alternating copolymers by the participation of charge-transfer (CT) complexes. The formation of CT complexes I-Manh and II-Manh was ascertained by UV and NMR spectroscopies. The equilibrium constants (K) could not be determined but were assumed to be small (K ? 1). For comparison with these systems an investigation of I-dimethyl maleate (DMM) and II-DMM systems was carried out to estimate K values 0.115 and 0.157 L/mol, respectively. To clarify the copolymerization mechanism I-Manh-acryronitrile was terpolymerized. Consequently it was concluded that the spontaneous copolymerization of I-Manh and II-Manh systems is effected by the CT complex monomer mechanism.     

Radiation-induced solid-state copolymerization of maleic anhydride and acenaphthylene

Radiation-induced solid-state copolymerization of the maleic anhydride–acenaphthylene system was carried out for the purpose of studying the solid-state polymerization of vinyl compounds in a binary system. Melting point measurement confirmed that this binary monomer system forms a eutectic mixture in the solid state. The solid-state polymerization of these monomers proceeds at maximum rate at the eutectic composition, and the polymerization products consist of a mixture of polyacenaphthylene and 1:1 maleic anhydride–acenaphthylene alternating copolymer. Since the 1:1 copolymer was obtained in solution polymerization also and maleic anhydride did not homopolymerize in solid state, it is considered that the solid-state copolymerization of maleic anhydride and acenaphthylene occurs in a liquidlike state at the boundary of the two monomer crystals.     

Charge-transfer complex formation and copolymerization of maleic anhydride with benzoselenophene

Under the influence of azobisisobutyronitrile, benzoselenophene and maleic anhydride slowly polymerize to form an alternating copolymer. The two comonomers form a charge-transfer complex (K^AD_c at 30° in chloroform: 0·22 l mol^?1). These properties of benzoselenophene are similar to those of benzothiophene and indole but are different from those of benzofuran. It is possible that the charge-transfer complex plays a role in the copolymerization.     

Living radical copolymerization of styrene/maleic anhydride

Styrene/maleic anhydride (MA) copolymerization was carried out using benzoyl peroxide (BPO) and 2,2,6,6‐tetramethyl‐1‐piperidinyloxy (TEMPO). Styrene/MA copolymerization proceeded faster and yielded higher molecular weight products compared to styrene homopolymerization. When styrene/MA copolymerization was approximated to follow the first‐order kinetics, the apparent activation energy appeared to be lower than that corresponding to styrene homopolymerization. Molecular weight of products from isothermal copolymerization of styrene/MA increased linearly with the conversion. However products from the copolymerization at different temperatures had molecular weight deviating from the linear relationship indicating that the copolymerization did not follow the perfect living polymerization characteristics. During the copolymerization, MA was preferentially consumed by styrene/MA random copolymerization and then polymerization of practically pure styrene continued to produce copolymers with styrene‐co‐MA block and styrene‐rich block. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 2239–2244, 2000     

Radical copolymerization of optically active l-menthyl vinyl ether with maleic anhydride,dimethyl maleate,and dimethyl fumarate

The copolymerizations of l-menthyl vinyl ether (l-MVE) with the monomers, that is, maleic anhydride (MAn), dimethyl maleate (DMM), and dimethyl fumarate (DMFu), were undertaken to obtain optically active copolymers. The optically active l-menthyl group in the side chain of copolymers was removed by the ether cleavage reaction with dry-hydrogen bromide gas. The ethercloven copolymers were still optically active. Hence it was concluded that asymmetric carbon atoms were introduced into the copolymer main chain, the reason given being that l-MVE and comonomers (MAn, DMM, and DMFu) made the stereoselective charge-transfer complex one another and copolymerized stereospecifically. From the results of the measurements of optical rotatory dispersion (ORD) and circular dichroism (CD) for copolymers before and after the ether cleavage reaction, the mode of bond opening for α,β-substituted monomers (MAn, DMM, and DMFu) was discussed and the microstructures of copolymers were prepared.     

Polymerization of vinylcyclopropanes. II

1,5-Type polymerization of vinylcyclopropane proceeding by the opening of both the double bond and the cyclopropane ring was found. Some other vinylcyclopropane derivatives, 1,1-dichloro-2-vinylcyclopropane, 1,1-dibromo-2-vinylcyclopropane, isopropenylcyclopropane, 1-methyl-1-vinylcyclopropane, 1,1-dichloro-2-methyl-2-vinylcyclopropane, and cis- and trans-1-chloro-2-vinylcyclopropane, were investigated. The observation of infrared spectra, NMR spectra, and other data indicated that the radical polymerization of these compounds gave principally 1,5-type polymer, while in cationic polymerization 1,2-type was predominant. The behavior of the polymerization was discussed in terms of the stability of a cyclopropylcarbinyl ion or radical which is formed in the initiation and propagation steps.     

Alternating copolymerization of β-methylstyrene and maleic anhydride

Alternating copolymers of β-methylstyrene and maleic anhydride were prepared by free-radical-initiated polymerization in bulk and in toluene as a solvent. The reactivity ratios k_1c/k₁₂ and k_2c/k₂₁ were calculated from the change of copolymerization rate with a monomer feed at a constant total monomer concentration according to the generalized model of Shirota and coworkers. From the equation R_p = R_p(f) + R_p(CT) were calculated R_p(f) and R_p(CT), and it was found that in toluene the copolymerization proceeds predominantly by the addition of CT-complex monomers. Termination occurs predominantly by homotermination of β-methyl-styrene macro free radicals, k_t22, but the cross termination k_t21 is also operative.     

Radiation-induced copolymerization of phenylvinyl alkyl ethers and maleic anhydride

Alternating copolymers of phenylvinyl ethyl ether ( I ) and phenylvinyl sec-butyl ether ( II ) with maleic anhydride (MAn) were prepared in bulk or in benzene solution by high-energy irradiation at dose rates of 42, 160, and 540 Gy/h, respectively. The overall energies of activation in copolymerization of I and II with MAn were 15.5 and 18.8 kJ/mol, respectively. The reaction proceeds by the free-radical mechanism and was found to be largely dependent on the bulkiness of the alkyl group. In the copolymerization of I and MAn, the molecular weight increases with conversion. By applying the model described by Shirota and co-workers, it was established that participation of charge-transfer-complex monomers increases with the increase of the total monomer concentration and with the bulkiness of the alkyl group in electron donor monomer.