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.     

Radical copolymerization of N-vinylformamide with unsaturated carboxylic acids

Radical precipitative copolymerization of N-vinylformamide with acrylic and methacrylic acids in isopropanol at 60°C, with azobisisobutyric acid dinitrile as initiator, was studied. The conditional values of the relative reactivities were found: r ₁ = 0.068 ± 0.008 and r ₂ = 1.638 ± 0.025 for the N-vinylformamide-methacrylic acid copolymer and r ₁ = 0.15 ± 0.03 and r ₂ = 0.19 ± 0.09 for the N-vinylformamide-acrylic acid copolymer.     

Copolymers of 2-deoxy-2-methacrylamido-D-glucose and unsaturated acids

New copolymers of the vinyl saccharide 2-deoxy-2-methacrylamido-D-glucose (M₁) with acrylic and methacrylic (M₂) acids differing in composition and molecular mass have been synthesized by free-radical copolymerization. The relative activities of the comonomers are determined. It is found that, for acrylic acid, r ₁ = 3.03 ± 0.15 and r ₂ = 0.5 ± 0.08 and, for methacrylic acid, r ₁ = 1.070 ± 0.1 and r ₂ = 1.18 ± 0.13. As is evidenced by potentiometric and viscometric measurements, the vinyl saccharide and acid units are capable of interacting, a circumstance that affects the conformational states of macromolecules.     

Copolymerization of acrylamide and styrene. II. Reactivity ratios with unperturbed acrylamide

It was reported earlier that the copolymerization of acrylamide and styrene is strongly affected by the copolymerization medium. The effect was attributed to a change in the polarity of the ethylenic bond in the acrylamide monomer due to hydrogen bonding and/or dipole—dipole interaction, depending on the medium. In view of those findings, it was suggested that absolute values for the reactivity ratios for the copolymerization of these two monomers might be obtained only when the acrylamide monomer is unperturbed. Copolymerizations of these monomers at a number of ratios, therefore, were done in benzene, which does not undergo hydrogen bonding and has no dipole moment, at high dilution, when amide—amide interactions between acrylamide molecules should be essentially eliminated. The values of r₁ and r₂(M₁ = acrylamide) were 9.14 ± 0.27 and 0.67 ± 0.08, respectively. There appears to be some indication in this system that high dilution adversely affects the reactivity of the acrylamide monomer while enhancing that of styrene. This aspect requires more study.     

Polymerization of meta-naphthoquinone methide: 3,4-benzo-6-methylenebicyclo [3.1.0] hex-3-ene-2-one

Polymerization behavior of meta-naphthoquinone methide, 3,4-benzo-6-methylenebicyclo[3.1.0]hex-3-ene-2-one ( 1 ), was studied. Radical initiator 2,2′-azobis(isobutyronitrile) (AIBN) induced polymerization of 1 , but ionic initiators potassium tert-butoxide, butyllithium, and boron trifluoride etherate did not. Polymerization of 1 proceeded via ring-opening and aromatization to give a polymer with head-to-tail monomer unit placement. Compound 1 copolymerized with methyl methacrylate (MMA) in the presence of AIBN to obtain the monomer reactivity ratios r₁ ( 1 ) = 0.28 ± 0.07 and r₂(MMA) = 0.39 ± 0.02 at 60°C and Q and e values of Q = 1.04 and e = −1.03, indicating that 1 is a conjugative and electron-donating monomer. Ring-opening and aromatization of 1 also took place in the copolymerization. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 741–746, 1997     

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.     

Alternating polyampholytes prepared by hydrolysis of copolymer of maleic anhydride and N-vinylsuccinimide

Alternating polyampholytes (MA-VA) containing two acidic groups and one basic group were prepared by the copolymerization of maleic anhydride (M₁) and N-vinylsuccinimide (M₂) at 60°C with AIBN as the initiator, followed by acid hydrolysis with 1N hydrochloric acid at 140°C for 24 hr. The monomer reactivity ratios r₁ and r₂ are 0.025 and 0.06, respectively. The structure of polymers was discussed on the basis of the data of their elementary, infrared (IR), and thermal analyses and the binding ability of heavy metal ion. Polyampholytes were soluble in strong acidic and basic media but were precipitated in the pH range 3–4. An isoelectric point at pH 3 was determined by potentiometric titration and the turbidimetric method. By thermal treatment above 205°C the polyampholyte turned quantitatively into a cyclized lactam. This suggests that the polyampholyte MA–VA has an intramolecular hydrogen bond between the amino and γ-carboxyl groups. The binding of Cu²⁺ and Hg²⁺ by the polyelectrolyte was evaluated by equilibrium dialysis.     

Alkali salts of (ω-sulphoxyalkyl)-acrylates and -methacrylates: Radical polymerization and copolymerization

A new preparation of alkali salts of (ω-sulphoxyalkyl)-acrylates and -methacrylates, by reaction of alkali salts of acrylic and methacrylic acids with cyclic sulphates, is described; spectral characterization of the products is described. The kinetics of the radical polymerization of sodium (2-sulphoxyethyl)methacrylate (SSEM) were studied; monomer reactivity ratios for copolymerization with methacrylic acid were: r₁ = 1.1 ± 0.15 and r₂ = 0.73 ± 0.05. Dark electrical surface conductivity of some homopolymers and copolymers with methacrylic acid was found to be 10⁴–10¹¹$\text{Ω}{}^{\mathrm{?1}}$, depending on relative humidity.     

Terpolymerization of Butadiene,Acrylonitrile, and Methacrylic Acid

Abstract

The terpolymerization of butadiene, acrylonitrile, and methacrylic acid in emulsion, using potassium persulfate as initiator and sodium dioctylsulphosuccinate as emulsifier, was investigated. For the binary system butadiene (M₁) and methacrylic acid (M₂), the following monomer reactivity ratios were determined: r₁₂ = 0.18 ± 0.05 and r₂₁ = 0.52 ± 0.09. When polymerizations were stopped at low conversions they gave terpolymers which show good agreement between experimental and theoretical copolymerization composition data, calculated from the Alfrey-Goldfinger equation. The relationships between monomer feed and terpolymer compositions are presented on triangular coordinate graphs as proposed by Slocombe. By using a computer program, the lines of unique composition and the lines of binary azeotropic composition were established. No point of true azeotropic composition was found, but a “pseudo-azeotropic” region was recognized. The influence of composition on glass transition temperature and thermal characteristics of the terpolymers is described.     

Copolymerization of Methacrylic Acid and N-Vinylpyrrolidone in Aqueous Solution

The monomer reactivity ratios for the copolymerization of methacrylic acid (MA) and N-vinylpyrrolidone (NVP) in aqueous media at 30°C were determined as a function of pH (range 2-10), by use of both the modified differential (YBR) and integrated copolymerization equation to process the data at high conversions (< 70% by weight). The reactivity ratio r₁ (for MA) ranges from 0.92 to 8.3 and that for NVP (r₂) is very small except at pH 7 and 8. The ri values show two minima: 2.9 at pH 4 and 0.92 at pH 8, nearly corresponding to the pKa values of the monomer MA and the polymer, respectively. Addition of 1 M sodium chloride results in an increase of n values, and the values are still lower than those of the undissoeiated acid. The trend of r_xwith pH is seen to follow that of the homopolymerization behavior of MA reported in the literature. The r₁ and r₂ are of the same order as those obtained in dimethylformamide in the literature.     

Effects of metal salts on polymerization. Part III. Radical polymerizabilities and infrared spectra of vinylpyridines complexed with zinc and cadmium salts

Radical polymerization of 4-vinylpyridine (4-VP), 2-vinylpyridine (2-VP), and 2-methyl-5-vinylpyridine (MVP) was studied in concentrated DMF solutions of ZnCl₂, ZnBr₂, ZnI₂, Zn(CH₃COO)₂, and Cd(CH₂COO)₂ at 50°C. Polymerization of 4-VP and MVP was accelerated by the addition of the metal salts, while the polymerization of 2-VP was greatly retarded. The sequence of the accelerating effect of metal salts for 4-VP was in the following order: Cd(CH₃COO)₂ > ZnCl₂ > Zn(CH₃COO)₂ > ZnBr₂ > ZnI₂. This sequence is almost the same as that reported in a previous report for MVP. However, the order was reversed for the retarding effect on the polymerization of 2-VP. At the intermediate concentration of metal salts, polymerization of 4-VP proceeded heterogeneously, which was explained by considering crosslinking of poly-4-VP by the metal ion. Since a linear correlation between the rate R_p and the degree of polymerization was observed for the 4-VP–Zn(CH₃COO)₂ system, the accelerating effect was postulated to be due to the enhancement in k_p. Results of copolymerization of VP with styrene as M₂ in a concentrated solution of Zn(CH₃COO)₂ indicated the strong activation of 4-VP by complex formation (r₁ = 2.7 ± 0.5, r₂ = 0.08 ± 0.03), whereas the change in the monomer reactivity of MVP is smaller (r₁ = 2.0 ± 0.2, r₂ = 0.35 ± 0.05). The behavior of 2-VP was abnormal (r₁ = 3.35 ± 0.3, r₂ = 0.55 ± 0.15, then r₁r₂ > 1), which was attributed to the steric effect by complex formation. Solid complexes formed between pyridine, 4-VP, 2-VP, or MVP and zinc salts were prepared as samples for infrared spectroscopy. The shifts in infrared absorption bands of these amines were studied by comparing the infrared spectra of the amines before and after the complex formation, and the results were interpreted in terms of electronic as well as steric interactions of metal salts with ligands. Conjugation of the metal salt with the ligand π-orbitals was necessary to explain both infrared spectra and polymerization results.     

Synthesis and polymerization of 5‐(methacrylamido)tetrazole,a water‐soluble acidic monomer

The reaction of methacryloyl chloride with 5‐aminotetrazole gave the polymerizable methacrylamide derivative 5‐(methacrylamido)tetrazole ( 4 ) in one step. The monomer had an acidic tetrazole group with a pK_a value of 4.50 ± 0.01 in water methanol (2:1). Radical polymerization proceeded smoothly in dimethyl formamide or, after the conversion of monomer 4 into sodium salt 4‐Na , even in water. A superabsorbent polymer gel was obtained by the copolymerization of 4‐Na and 0.08 mol % N,N′‐methylenebisacrylamide. Its water absorbency was about 200 g of water/g of polymer, although the extractable sol content of the gel turned out to be high. The consumption of 4‐Na and acrylamide (as a model compound for the crosslinker) during a radical polymerization at 57 °C in D₂O was followed by ¹H NMR spectroscopy. Fitting the changes in the monomer concentration to the integrated form of the copolymerization equation gave the reactivity ratios r _4‐Na = 1.10 ± 0.05 and r_acrylamide = 0.45 ± 0.02, which did not differ much from those of an ideal copolymerization. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4333–4343, 2002     

On the copolymerization model and microstructure of methyl acrylate - styrene radical copolymer. Influence of ZnCl2

Bulk radical copolymerization of methyl acrylate (MeA, M₁) with styrene (St, M₂) in presence and absence of ZnCl₂ as complexing agent was studied. ¹H-NMR spectra were used to establish copolymer composition and sequence distribution. The methoxy group signal was observed to be split due to pentads, but the analysis of sequence distribution is possible only at triad level. Both composition and sequence distribution data confirmed that bulk radical copolymerization respects quite well the terminal addition model; the values of r₁ = 0.14 ± 0.02 (from composition data) and r₁ = 0.25 ± 0.03 (from sequence distribution data) and r₂ = 0.83 ± 0.10 (from composition data) were found. The presence of ZnCl₂ increases the probability of alternating addition, e.g., for [ZnCl₂]/[MeA] = 0.2, r₁ = 0.03 ± 0.02 and r₂ = 0.17 ± 0.03. The radical copolymer obtained in bulk in the absence of ZnCl₂ presents a coisotactic configuration with σ = 0.75 ± 0.03, but the presence of the complexing agent reduces the probability of coisotactic addition, e.g., for [ZnCl₂]/[MeA] = 0.2, σ = 0.52 ± 0.03.     

Preparation of carboxyl‐end‐group polyacrylamide with low polydispersity by ATRP initiated with chloroacetic acid

Atom transfer radical polymerization (ATRP) of acrylamide was successfully carried out with chloroacetic acid as initiator and CuCl/N,N,N′,N′‐tetramethylethylenediamine (TMEDA) as catalyst either in water at 80 °C or in glycerol–water (1:1 v/v) medium at 130 °C. In both cases, carboxyl‐end‐group polyacrylamide was obtained with lower polydispersity ranging from 1.03 to 1.44 depending on the polymerization condition. Polymerization kinetics showed that the polymerizations proceeded with a living/controlled nature and accelerated at a higher temperature. The effect of pH in the reaction system on the polymerizations was further studied, revealing that chloroacetic acid not only served as a functional initiator for the ATRP of acrylamde but also provided the acidic polymerization condition, which effectively protected the ATRP of acrylamide from the unexpected complexation and cyclization side‐reactions. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3956–3965, 2007     

Copolymerization of the poly(<Emphasis Type="Italic">N,N</Emphasis>-dimethyl-<Emphasis Type="Italic">N,N</Emphasis>-diallylammonium chloride) macromonomer with acrylamide

Copolymers of the poly(N,N-dimethyl-N,N-diallylammonium chloride) macromonomer (1′) with acrylamide (2) with a high content of cationic groups (up to 50%) were synthesized. The relative activities r _1′ and r ₂ were calculated. The relative activities calculated by the Kelen—Tudos (r _1′ = 0.057±0.009, r ₂ = 1.57±0.12) and Feynman—Ross (r _1′ = 0.055±0.011, r ₂ = 1.58±0.14) methods are in accordance. The intrinsic viscosity and the yield of copolymers were found to decrease with an increase in the molar fraction of macromonomer 1′ in the monomer mixture. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 515–518, March, 2007.     

The influence of molecular interactions on polymerization—IV: Copolymerization of 2-naphthyl methacrylate and methyl methacrylate in solvents with different dielectric constants

The copolymerization of 2-naphthyl methacrylate (2-NM) with methyl methacrylate (MMA) initiated by 2,2′-azoisobutyronitrile in carbon tetrachloride, chloroform, benzene, acetone and acetonitrile was investigated. The reactivity ratios determined by the methods of Fineman-Ross and Kelen-Tüdo&#x030B;s are: in carbon tetrachloride—r_2-NM = 2.46 ± 0.25, r_MMA = 0.61 ± 0.06; chloroform—r_2-NM = 2.71 ± 0.30, r_MMA = 0.60 ± 0.06; benzene—r_2-NM = 2.62 ± 0.44, r_MMA = 0.63 ± 0.11; acetone—r_2-NM = 4.13 ± 0.45, r_MMA = 0.60 ± 0.06 and acetonitrile—r_2-NM = 3.70 ± 0.30, r_MMA = 0.62 ± 0.05.The dependence of the reactivity ratios on the solvent is explained on the basis of formation of complexes between the electron-donating naphthalene rings and the electron-accepting methacrylic double bonds, as indicated by NMR studies.     

Investigation of fulvic acid photochemistry in aqueous solutions by stationary and laser flash photolysis techniques

Photochemistry of fulvic acid (FA, Henan ChangSneng Corporation) in aqueous solutions was studied using stationary and nanosecond laser (355 nm) flash photolysis. UV-excitation leads to formation of FA triplet state which is characterized by wide unstructured absorption band with maximum at 620 nm. The yield of FA triplet state depends on pH: intermediate absorption signal is maximal at neutral pH (6–7) and decreases in basic and acidic media. Kinetics of triplet state decay does not depend on solution pH and exhibits multiexponential character with characteristic times t ₁ = 4.3 ± 2.2, t ₂ = 54 ± 28, t ₃ = 830 ± 240 μs.     

Emulsifier-free emulsion copolymerization of styrene and butyl acrylate. II. Kinetic studies in the presence of ionogenic comonomers

Batch emulsifier-free copolymerizations of styrene (S) and butyl acrylate (BuA) have been performed for a S/BuA weight ratio = 50/50 in the presence of two types of functional comonomers [methacrylic acid (MAA) at different pHs] or potassium sulfopropylmethacrylate (SPM) and two initiators [potassium persulfate or 4–4′azobiscyanopentanoic acid (AZO)]. The use of AZO/MAA system results in the formation of polymer particles with only surface carboxylic end groups. The particle size of the final latexes can be adjusted with the MAA concentration, provided the polymerization is carried out at pH > 6.5. However, the higher the MAA concentration, the sooner the polymerization levels off in conversion. With the K₂S₂O₈/SPM system, particles bearing only sulfate and sulfonate groups are produced and the polymerization is complete. In that case, the particle size of the final latexes is smaller than with the previous system and 30% of the SPM is fixed on the particle surface, instead of 10% with MAA. Using SPM, a too high functional monomer concentration results in the latex destabilization caused by the formation of a large amount of polyelectrolytes. Kinetic studies indicate that most of the functional monomer is incorporated onto the particle surface during the last 30% conversion of the polymerization. A tentative explanation of such a behavior is discussed, based on the existence of two polymerization loci in the latex system.     

Effect of pH and ionic strength on the interaction of humic acid with aluminium oxide

The effect of pH and neutral electrolyte on the interaction between humic acid/humate and γ-AlOOH (boehmite) was investigated. The quantitative characterization of surface charging for both partners was performed by means of potentiometric acid–base titration. The intrinsic equilibrium constants for surface charge formation were logK _a,1 ^int=6.7±0.2 and logK _a,2 ^int = 10.6±0.2 and the point of zero charge was 8.7±0.1 for aluminium oxide. The pH-dependent solubility and the speciation of dissolved aluminium was calculated (MINTEQA2). The fitted (FITEQL) pK values for dissociation of acidic groups of humic acid were pK ₁ = 3.7±0.1 and pK ₂ = 6.6±0.1 and the total acidity was 4.56 mmol g⁻¹. The pH range for the adsorption study was limited to between pH 5 and 10, where the amount of the aluminium species in the aqueous phase is negligible (less than 10⁻⁵ mol dm⁻³) and the complicating side equilibria can be neglected. Adsorption isotherms were determined at pH ∼ 5.5, ∼8.5 and ∼9.5, where the surface of adsorbent is positive, neutral and negative, respectively, and at 0.001, 0.1, 0.25 and 0.50 mol dm⁻³ NaNO₃. The isotherms are of the Langmuir type, except that measured at pH ∼ 5.5 in the presence of 0.25 and 0.5 mol dm⁻³ salt. The interaction between humic acid/humate and aluminium oxide is mainly a ligand-exchange reaction with humic macroions with changing conformation under the influence of the charged interface. With increasing ionic strength the surface complexation takes place with more and more compressed humic macroions. The contribution of Coulombic interaction of oppositely charged partners is significant at acidic pH. We suppose heterocoagulation of humic acid and aluminium oxide particles at pH ∼ 5.5 and higher salt content to explain the unusual increase in the apparent amount of humic acid adsorbed. Received: 20 July 1999 /Accepted in revised form: 20 October 1999     

Kinetic Investigations of Self-Condensing Group Transfer Polymerization

Hyperbranched methacrylates were synthesized by Self-Condensing Group Transfer Polymerization (SCGTP) of 2-(2-methyl-1-triethylsiloxy-1-propenyloxy)ethyl methacrylate (MTSHEMA) and characterized by multi-detector SEC as well as quantitative ¹³C-NMR. Kinetic measurements revealed that side reactions limit the molecular weights and lower the polydispersity. A maximum degree of branching of DB ≈ 0.4 and a reactivity ratio, r = k _A/k _B = 18 ± 5, was determined.