Copolymerization of vinyl monomers with irradiated acrylamide crystals

Liquid vinyl monomers (styrene and methyl methacrylate) were copolymerized with γ-irradiated acrylamide in a two-phase system. The products obtained were mainly diblock copolymers of acrylamide and the vinyl monomer used, but small amounts of homopolymers were also formed. The effects of radiation dose, copolymerization temperature, initial molar ratio of monomers, crystal size of acrylamide, mode of irradiation, and the existence of a solvent were investigated. In addition to the conventional methods, the reaction was studied by electron spin resonance spectroscopy. A mechanism was proposed and a kinetic rate equation was established for this copolymerization. Characterization of the copolymers was made by physical and mechanical testing.     

Copolymerization of new pyrazolone-containing monomers with certain vinyl comonomers

The polymerization ability of two new pyrazolone-containing monomers—3-methyl-1-phenyl-4-crotonoyl-pyrazolone-5 ( Cr ) and 3-methyl-1-phenyl-4-(3′-phenyl-acryloyl) pyrazolone-5 ( Cy )—was investigated. The monomers were obtained by acylation of 3-methyl-1-phenyl-pyrazolone-5 with crotonyl chloride or cinnamoyl chloride, respectively. It was established that the two monomers do not homopolymerize either under the action of ionic and radical initiators nor with γ-rays (doses between 2 and 10 MRad). In contrast to this, the two monomers copolymerize with other vinyl comonomers. Copolymers of Cr and Cy with methacrylic acid (MAA), methyl methacrylate (MMA), and Styrene (St) were synthesized by radical copolymerization. The molecular weights of the polymer products obtained were in the 10,000–65,000 range. It was established that the molecular weight characteristics of the copolymers were affected by the concentration of the pyrazolone-containing monomer and by the chemical nature of the solvent used. The copolymerization of Cr and Cy with MAA was investigated in detail in order to evaluate the relative activity of the new monomers during copolymerization. The reactivity ratios (r) were calculated by three different methods with good agreement. The values obtained for the monomer pairs are: r_MAA = 0.61 ± 0.01, r_Cr = 0.04 ± 0.01; r_MAA = 0.64 ± 0.05, r_Cy = 0.02 ± 0.02. The Q/e values for Cr and Cy were determined using the reactivity ratios of both monomers.     

Copolymerization and copolymers of brominated phenylmaleimides with some vinyl monomers

The kinetics of the free radical copolymerization in solution of N-(4-bromophenyl)maleimide (MBPMI), N-(2, 4-dibromophenyl)maleimide (DBPMI) and N-(2, 4, 6-tribromophenyl)maleimide (TBPMI) with styrene (St), methyl acrylate (MA), methyl methacrylate (MMA) and acrylonitrile (AN) at low and high conversions were described. Some characteristic properties of the copolymers obtained, particularly their thermal behaviour were also presented.     

Copolymerization parameters of acrolein and acidic vinyl monomers

Acrolein was copolymerized by radical initiation in aqueous solutions with sodium p-styrenesulfonate and acrylic acid, respectively, in the pH range of 3–7. The reactivities were shown to be pH-dependent. For the acrolein (M₁)–sodium p-styrenesulfonate (M₂) pair, r₁ = 0.33 ± 0.15 and r₂ = 0.32 ± 0.05 at pH 3; r₁ = 0.23 ± 0.12 and r₂ = 0.05 ± 0.03 at pH 5; r₁ = 0.26 ± 0.03 and r₂ = 0.025 ± 0.025 at pH 7. For the acrolein (M₁)–acrylic acid (M₂) pair, r₁ = 0.50 ± 0.30 and r₂ = 1.15 ± 0.2 at pH 3; r₁ = 2.40 ± 0.50 and r₂ = 0.05 ± 0.05 at pH 5; r₁ = 6.70 ± 3.00 and r₂ = 0.00 at pH 7. For acrolein, the new values of Q = 1.6 and e = 1.2 have been calculated. For sodium p-styrenesulfonate, the values Q = 0.76 and e = ?0.26 at pH 3, Q = 0.51 and e = ?0.87 at pH 5, Q = 0.39 and e = ?1.00 at pH 7 were obtained; and for acrylic acid, the values Q = 1.27 and e = 0.50 at pH 3, Q = 0.11 and e = ?0.22 at pH 5 were derived. The changes in reactivity are explained on the basis of inductive and resonance effects.     

Functional monomers and polymers. XIX. Copolymerization of vinyl monomers containing nucleic acid bases

Taking into account the specific base–base interaction existing between nucleic acid molecules, we studied the free-radical copolymerization of N-β-methacryloyloxyethyl derivative of uracil with that of adenine at 60°C in various solvents. N-β-Methacryloyloxyethyltheophylline as well as methyl methacrylate were used also as comonomers. From the data on the rates in different comonomer feed ratios and the r₁ and r₂ values obtained, copolymerizability was discussed in some detail. The results suggest that the interaction between uracil and adenine bases plays a role in the copolymerization behavior.     

Vinylhydroquinone. III. Copolymerization of vinylhydroquinone and vinyl monomers by tri-n-butylborane

The copolymerization of vinylhydroquinone (VHQ) and vinyl monomers, e.g., methyl methacrylate (MMA), 4-vinyl-pyridine (4VP), acrylamide (AA), and vinyl acetate (VAc), by tri-n-butylborane (TBB) was investigated in cyclohexanone at 30°C under nitrogen. VHQ is assumed to copolymerize with MMA, 4VP, and AA by vinyl polymerization. The following monomer reactivity ratios were obtained (VHQ = M₂): for MMA/VHQ/TBB, r₁ = 0.62, r₂ = 0.17; for 4VP/VHQ/TBB, r₁ = 0.57, r₂ = 0.05; for AA/VHQ/TBB, r₁ = 0.35, r₂ = 0.08. The Q and e values of VHQ were estimated on the basis of these reactivity ratios as Q = 1.4 and e = ?;1.1, which are similar to those of styrene. This suggests that VHQ behaves like styrene rather than as an inhibitor in the TBB-initiated copolymerization. No homopolymerization was observed either under nitrogen or in the presence of oxygen. The reaction mechanism is discussed.     

Copolymerization of 2-methylene-4-phenyl-1,3-dioxolane with electrophilic vinyl monomers through zwitterionic mechanism

Spontaneous copolymerization of cyclic ketene acetal, 2-methylene-4-phenyl-1,3-dioxolane ( I ) with common electrophilic vinyl monomers, such as methyl α-cyanoacrylate (MCA), acrylonitrile (AN), and methyl methacrylate (MMA) were investigated to further explore zwitterion polymerization method with cyclic ketene acetals. In the reaction of I with MCA and AN, spontaneous copolymerization took place at ambient temperature. The copolymers of I with MCA gave low molecular weight polymers, but copolymers obtained with I and AN were high molecular weight polymers. In the reaction of I and MMA, high molecular weight copolymer was obtained only at temperatures above 80°C. Thus, obtained polymers were not the alternating copolymers and possessed high I content in all the cases. From the above results, macrozwitterionic mechanism was suggested as discussed.     

Sulfur-containing vinyl monomers. XIII. Cationic copolymerizations of vinyl sulfides with some vinyl monomers

Cationic copolymerizations of vinyl sulfides (VS) with some vinyl monomers with boron tri-fluoride-diethyl etherate catalyst were investigated to evaluate their monomer reactivities. The effects of VS on the copolymer yield and viscosity of the resulting copolymers revealed the inhibition or retardation mechanism which was explained in terms of the formation of a stable vinylsulfonium salt by the reaction between a propagating carbonium ion and VS monomer. From the results of copolymerizations of phenyl vinyl sulfide (PVS) with isobutyl vinyl ether (IBVE), β-chloroethyl vinyl ether (CEVE), α-methylstyrene (α-MeSt), and styrene (St), the relative reactivities of these monomers were found to be in the following order: IBVE > CEVE > PVS > α-MeSt > St. The relatively higher reactivity of PVS than St derivatives was explained on the basis of the conjugative and electron-donating nature of the VS monomer. The effects of alkyl and para-substituted phenyl groups in vinyl sulfides on their reactivities toward the propagating carbonium ion were correlated with polar factors and compared with those of the hydrolysis of α-mercaptomethyl chlorides. The transition state for the propagation reaction in cationic polymerization of VS was proposed to be a π-complex type structure.     

Synthesis and characterization of optically active polyamides derived from carbohydrate-based monomers

The synthesis of three new stereoregular AB-type polyamides based on D -ribono-1,4-lactone, L -arabinose, and D -xylose has been carried out by the active ester polycondensation method. These polyamides were characterized by elemental analysis, IR and NMR spectroscopies, and powder X-ray diffraction. They displayed optical activity and had a pronounced affinity to water, although they were not soluble in this solvent. The polyamide obtained from D -ribono-1,4-lactone was highly crystalline and yielded films with spherulitic texture. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 3645–3653, 1997     

Copolymerization of fluorinated monomers with nonfluorinated monomers. Reactivity and mechanisms

The copolymerization of two monomers usually leads to random copolymers except when one of both bears an electron-acceptor group and the other one has an electron-donor group. Many copolymers are commercially available, mainly in the series of hydrogenated monomers (S.M.A., GANTREZ, MALIALIM resins). The field of fluorinated copolymers is very interesting because of the strong electron-acceptor behaviour of the fluorine atoms and more generally of halogenated atoms. Thus, after HALAR (CTFE^a)-ethylene), TEFZEL (TFE-ethylene) and AFLAS (TFE^b)-propylene) resins, a new series of resins have been produced (copolymers of CTFE and vinyl ethers commercialized by ASAHI Corp.). So it can be considered that ACCEPTOR-DONOR copolymerization with fluorinated monomers is one of the most important applications of that kind of research. After reminding the main mechanisms of that reaction (homopolymerization of charge transfer complex and copolymerization of free monomers), it will be discussed about the mechanism in some examples (CTFE-vinyl ethers and other pairs of monomers). Then it will be explained how cotelomerization has provided new data to prefer a copolymerization mechanism by free monomers.     

Asymmetric induction copolymerization of optically active l-menthyl vinyl ether with styrene and N-phenylmaleimide

The copolymerizations of l-menthyl vinyl ether (l-MVE) with styrene (St) and N-phenylmaleimide (N-PMI) as comonomers were carried out in benzene with azobisisobutyronitrile (AIBN) as an initiator to give optically active copolymers. After the removal of the optically active menthyl group by use of hydrogen bromide gas, the ether-cloven l-MVE-N-PMI copolymer (VA-N-PMI) was still optically active. On the other hand, the optical activity of l-MVE-St copolymer disappeared after ether cleavage. It is thought that asymmetric induction took place in the polymer main chains. The optical rotatory dispersion and circular dichroism of the original and ether-cloven copolymers were measured in order to confirm the asymmetric induction.     

Copolymerization of vinyl acetate with benzylidenemalononitrile

Vinyl acetate was copolymerized with benzylidenemalononitrile in bulk by radical initiation at 80°C up to low conversions. Alternating copolymers were formed over a wide range of monomer feed ratios. The copolymerization parameters were determined by the conventional scheme. The copolymers were characterized by IR, proton, and ¹³C spectroscopy and their basic properties, solubility, viscosity, and thermal behavior were determined.     

Studies of the polymerization of diallyl compounds. XXVII. Copolymerization of diallyl tartrate with several vinyl monomers

The radical copolymerization of diallyl tartrate (DATa) (M₁) with diallyl succinate (DASu), diallyl phthalate (DAP), allyl benzoate (ABz), vinyl acetate (VAc), or styrene (St) was investigated in order to disclose in more detail the characteristic hydroxyl group's effect observed in the homopolymerization of DATa. In the copolymerization with DASu or DAP as a typical diallyldicarboxylate, the dependence of the rate of copolymerization on monomer composition was different for different copolymerization systems and unusual values larger than unity for the product of monomer reactivity ratios, r₁r₂, were obtained. In the copolymerization with ABz or VAc (M₂), the r₁ and r₂ values were estimated to be 1.50 and 0.64 for the DATa/ABz system and 0.76 and 2.34 for the DATa/VAc system, respectively; the product r₁r₂ for the latter copolymerization system was found again to be larger than unity. In the copolymerization with St, the largest effect due to DATa monomer of high polarity was observed. Solvent effects were tentatively examined to improve the copolymerizability of DATa. These results are discussed in terms of hydrogen-bonding ability of DATa.     

Copolymerization of acrylamide with allyl-acrylate quaternary ammonium monomers

A series of copolymers of N,N-morpholine-N-2-(ethoxycarbonyl)allyl allyl ammonium chloride, N,N-morpholine-N-2-(ethoxycarbonyl)allyl allyl ammonium bromide, N,N-piperidyl-N-2-(ethoxycarbonyl)allyl allyl ammonium chloride, N,N-morpholine-N-2-(t-butoxycarbonyl)allyl allyl ammonium bromide and diallyldimethylammonium chloride (DADMAC) with acrylamide (AAm) were prepared in water at 50-56°C using 2,2'-azo-bis(2-amidinopropane)dihydrochloride (V-50). The ethyl ester monomers showed high cyclization efficiencies during copolymerizations. The tert-butyl ester derivatives showed high cross-linking tendencies. The molar fractions of allyl-acrylate monomers in the AAm: allyl-acrylate copolymers were higher than the one of DADMAC in the AAm:DADMAC copolymers. The intrinsic viscosities of the copolymers measured in 0.09 M NaCl ranged from 2.5 to 7.5 dL/g.     

Copolymerization of glycidyl methacrylate with alkyl acrylate monomers

A newer approach to obtaining acrylic thermoset polymers with adequate hydrophilicity required for various specific end uses is reported. Glycidyl methacrylate (GMA) was copolymerized with n-butyl acrylate (n-BA), isobutyl acrylate (i-BA), and 2-ethylhexyl acrylate (2-EHA) in bulk at 60°C. with benzoyl peroxide as free radical initiator. The copolymer composition was determined from the estimation of epoxy group. Reactivity ratios were calculated by the Yezrielev, Brokhina, and Roskin method. For copolymerization of GMA (M₁) with n-BA (M₂) the reactivity ratios were r₁ = 2.15 ± 0.14, r₂ = 0.12 ± 0.03; with i-BA (M₂) they were r₁ = 1.27 ± 0.06, r₂ = 0.33 ± 0.031; and with 2-EHA (M₂) they were r₁ = 2.32 ± 0.14, r₂ = 0.13 ± 0.009. The reactivity ratios were the measure of distribution of monomer units in a copolymer chain; the values obtained are compared and discussed.