Kinetic study of copolymerization of acrylonitrile with ammonium acrylate

Ammonium acrylate was first used to successfully copolymerize with acrylonitrile. Kinetics of copolymerization of acrylonitrile with ammonium acrylate was investigated in a H₂O/dimethylsulfoxide (DMSO) mixture. The rate of copolymerization and particle size were measured. Kinetic equation of the copolymerization was obtained. Effect of copolymerization systems on monomer apparent reactivity ratios for acrylonitrile/ammonium acrylate copolymers was studied in comparison. Values of monomer apparent reactivity ratios were calculated by Kelen‐Tudos method. It has been found that monomer apparent reactivity ratios in water‐rich reaction medium [H₂O/DMSO>80/20] are approximately equivalent to those in aqueous suspension polymerization system. In DMSO‐rich reaction medium (DMSO/H₂O > 80/20), apparent reactivity ratios are similar to those in solution polymerization system. With an increase in polarity of solvent, values of apparent reaction ratios both decrease. The values of apparent reaction ratios gradually tend to 1 with increase in the copolymerization temperature. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4679–4683, 2006     

Copolymerization kinetics of acrylonitrile with amino ethyl‐2‐methyl propenoate in H2O/DMSO mixture

Amino ethyl‐2‐methyl propenoate (AEMP) was used successfully to copolymerize with acrylonitrile (AN). This was achieved by using azobisisobutyronitrile as the initiator. Kinetics of copolymerization of AN with AEMP was investigated in H₂O/dimethylsulfoxide (DMSO) mixture between 50 and 70 °C under N₂ atmosphere. The rate of copolymerization was measured. The kinetic equation of copolymerization system was obtained and the overall activation energy for the copolymerization system was determined. Values of monomer apparent reactivity ratios were calculated using Kelen–Tudos method. It has been found that the apparent reactivity ratios in aqueous suspension polymerization system are similar to those in solution polymerization system at polymerization conversion less than 25%. At conversion beyond 45%, the changes of monomer apparent reactivity ratios become less prominent. In water‐rich reaction medium (H₂O/DMSO > 70/30), monomer apparent reactivity ratios are approximately equivalent to those in aqueous suspension polymerization system. In DMSO‐rich reaction medium (DMSO/H₂O > 70/30), apparent reactivity ratios are similar to those in solution polymerization system. With an increase of polarity of solvent, values of apparent reaction ratios both decrease. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2095–2100, 2006     

A microstructural analysis of isoprenol ether-based polycarboxylates and the impact of structural motifs on the dispersing effectiveness

Generally, polycarboxylate superplasticizers (PCEs) are synthesized via aqueous free radical copolymerization. The conditions during copolymerization such as relative reactivity and feeding mode and ratio of monomers can cause different monomer sequences in the final product. In this study, the sequence of monomers in PCE polymers synthesized from acrylic acid and isoprenyloxy polyethylene glycol (IPEG) macromonomer was characterized by ¹³C nuclear magnetic resonance (NMR) spectroscopy. Three different triads of monomer sequences (EAE, AAE and AAA; E = ether, A = acid monomer) were detected. It was found that IPEG PCEs predominantly contain the structural motifs of AAE and EAE, and less of AAA. Higher additions of acrylic acid do not incorporate into the structure of PCE, but convert to HMW polyacrylate as by-product instead. A PCE with optimal dispersing effectiveness was achieved at high contents of IPEG macromonomer, a molecular weight (M_w) around 40,000 Da and narrow molecular weight distribution.     

Monomer apparent reactivity ratios for acrylonitrile/methyl vinyl ketone copolymerization system

Methyl vinyl ketone was firstly used to successfully copolymerize with acrylonitrile. This was achieved by using azobisisobutyronitrile as the initiator, and dimethyl sulfoxide as the solvent. Effect of copolymerization systems on monomer apparent reactivity ratios for copolymer of acrylonitrile with methyl vinyl ketone was studied for contrast. Values of monomer apparent reactivity ratios were calculated by Kelen–Tudos method. It has been found that the apparent reactivity ratios in aqueous suspension polymerization system were similar to those in solution polymerization system at polymerization conversion less than 20%. Beyond 50% of conversion, the changes of monomer apparent reactivity ratios become less prominent. In water‐rich reaction medium [(H₂O/dimethylsulfoxide (DMSO)>80/20), monomer apparent reactivity ratios were approximately equivalent to those in aqueous suspension polymerization system. In DMSO‐rich reaction medium (DMSO/H₂O > 80/20), apparent reactivity ratios were similar to those in solution polymerization system. Values of apparent reaction ratios both decreased when AN/MVK copolymer was synthesized in DMF and DMAc. The values of apparent reaction ratios gradually tend to 1 with increasing the copolymerization temperature. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4045–4048, 2006     

Copolymerization of acrylonitrile with methyl vinyl ketone

Methyl vinyl ketone (MVK) was first used to successfully copolymerize with acrylonitrile (AN). This was achieved with azobisisobutyronitrile as the initiator. The kinetics of the copolymerization of AN with MVK were investigated in a H₂O/dimethyl sulfoxide (DMSO) mixture between 50 and 70°C under N₂ atmosphere. The rate of copolymerization was measured. The kinetic equation of the copolymerization system was obtained, and the overall activation energy for the copolymerization system was determined. The values of the monomer apparent reactivity ratios were calculated by the Kelen–Tudos method. In a DMSO‐rich reaction medium (DMSO/H₂O > 80/20), the monomer apparent reactivity ratios were similar to those in the solution polymerization system. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1940–1944, 2006     

Monomer apparent reactivity ratios for acrylonitrile/ammonium itaconate radical copolymerization systems

Ammonium itaconate was first used to copolymerize with acrylonitrile. This was achieved by using azobisisobutyronitrile as the initiator and dimethyl sulfoxide as the solvent. Effects of copolymerization systems on monomer apparent reactivity ratios for acrylonitrile/ammonium itaconate copolymers were studied. The values of monomer apparent reactivity ratios were calculated by Kelen‐Tudos method. The apparent reactivity ratios in the aqueous suspension polymerization system are similar to those in the solution polymerization system at polymerization conversions of less than 18% [reactivity ratio of acrylonitrile (r_AN) = 0.47 ± 0.01, reactivity ratio of ammonium itaconate (r_AIA) = 3.08 ± 0.01]. At conversions of more than 50%, the changes of monomer apparent reactivity ratios become less prominent (r_AN = 0.68 ± 0.01, r_AIA = 2.47 ± 0.01). In water‐rich reaction medium [(H₂O/dimethylsulfoxide (DMSO) > 80/20)], the monomer apparent reactivity ratios are approximately equivalent to those in the aqueous suspension polymerization system. In DMSO‐rich reaction medium (DMSO/H₂O > 80/20), the apparent reactivity ratios are similar to those in the solution polymerization system. With an increase in the polarity of the solvent, the values of apparent reaction ratios both decrease. The values of apparent reaction ratios gradually tend to 1 with increasing the copolymerization temperature. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3920–3923, 2007     

Study on the Copolymerization Kinetics of 8-Quinolinyl Methacrylate with Methyl Methacrylate,n-Butyl Methacrylate and Styrene

Abstract

The 8-quinolinyl methacrylate (8-QMA) monomer was prepared and characterized by the conventional methods of analysis. The 8-QMA monomer was copolymerized with methyl methacrylate (MMA), n-butyl methacrylate (BMA) and styrene under different monomer feed ratio using azobisisobutyronitrilic (AIBN) as an initiator by solution copolymerization. The polymerization reaction was allowed to proceed only upto sim; 10%. The composition of the resulting copolymers was determined by UV-visible spectrophotometry and reactivity ratio for each monomer pair was calculated. The relative reactivity of the monomers was discussed on the basis of the size of alkyl group in methacrylates and effect of resonance on the stability of the styryl radicals during the copolymerization.     

Synthesis and copolymerization of halogen phenyl-substituted methyl 2-cyano-3-phenyl-2-propenoates with styrene

Summary Halogen phenyl-substituted methyl 2-cyano-3-phenyl-2-propenoates, RC₆H₄CH=C(CN)CO₂CH₃ (R= 2-fluoro, 3-fluoro, 2-bromo, and 3-bromo), were prepared by the piperidine catalyzed Knoevenagel condensation of corresponding substituted benzaldehydes and methyl cyanoacetate. Novel copolymers of the propenoates and styrene were prepared at equimolar monomer feed by solution copolymerization in the presence of a radical initiator. The order of relative reactivity (1/r ₁) was 3Br (3.02) > 2Br (2.63) > 3F (1.84) > 2F (1.66). High glass transition temperatures of the copolymers compared that of polystyrene indicates a substantial decrease in chain mobility of the copolymers due to the high dipolar character of the trisubstituted ethylene monomer unit. Received: 9 February 1998/Revised version: 5 March 1998/Accepted: 5 March 1998     

Monomer-to-water ratios as a tool in controlling emulsion copolymer composition: The methyl acrylate–indene system

A drifting copolymer composition as a function of conversion is an aspect typical of copolymerization. Reducing this so-called composition drift in batch copolymerizations will lead to a decrease in chemical heterogeneity of the copolymers formed. For monomer systems in which the more water-soluble monomer is also the more reactive one, theory predicts that composition drift in emulsion copolymerization can be reduced or even minimized by optimizing the monomer-to-water ratio. The monomer combination methyl acrylate–indene (MA–Ind) meets the requirements needed to minimize composition drift in batch emulsion copolymerization. Therefore, this monomer combination is chosen as a model monomer system in order to verify this theoretical prediction. Reactivity ratios needed for model predictions have been determined by low conversion bulk polymerization, resulting in r_MA = 0.92 ± 0.16 and r_Ind = 0.086 ± 0.025. Furthermore, emulsion copolymerization reactions at the same monomer mole fraction are performed at different monomer to water ratios. From the good agreement between experiments and theoretical predictions for MA–Ind, it was concluded that control and even minimization of composition drift in batch emulsion copolymerization for monomer systems in which the more water-soluble monomer is also the more reactive one is indeed possible by changing the initial monomer-to-water ratio of the reaction mixture provided that the reactivity ratios of both monomers are not too far from unity. © 1994 John Wiley & Sons, Inc.     

Grafting onto wool. XVI. Graft copolymerization of vinyl monomers by use of TBHP–FAS as redox initiator

Methyl acrylate (MA), methyl methacrylate (MMA), and n-butyl vinyl ether (n-BVE) have been graft-copolymerized onto Himachali wool in an aqueous medium by using tertiary butyl hydroperoxide ferrous ammonium sulfate (TBHP-FAS) redox system at 40°C, 50°C, 60°C, and 70°C for various reaction periods. Percentage of grafting and percent efficiency have been determined as functions of concentration of monomers, molar ratios of [TBHP]/[FAS], time and temperture. Molar ratios of [TBHP]/[FAS] were found to influence grafting of different monomers studied. Chemical evidence indicates that a covalent bond formation occurs between grafted polymeric chain and backbone polymer. The rate of grafting (R_p) and induction period (I_p) of different monomers towards graft copolymerization were determined as function of total initial monomer concentrations. R_p and I_p of n-BVE are independent of total initial monomer concentrations while R_p and I_p of both MA and MMA were found to depend on the total initial monomer concentrations. MA, MMA, and n-BVE were found to differ in reactivity towards grafting onto wool in the presence of (TBHP-FAS) redox system; the following reactivity order was observed: MMA > MA > n-BVE.     

Novel copolymers of trisubstituted ethylenes with styrene — 7. Methyl 2-cyano-3-dihalophenyl-2-propenoates

Summary Methyl 2-cyano-3-dihalophenyl-2-propenoates, R₂C₆H₃CH=C(CN)CO₂CH₃ (R₂= 2,4-difluoro, 2,5-difluoro, 2,6-difluoro, 3,4-difluoro, 3,5-difluoro, and 2-chloro-6-fluoro), were prepared by the piperidine catalyzed Knoevenagel condensation of corresponding disubstituted benzaldehydes and methyl cyanoacetate. Novel copolymers of the propenoates and styrene were prepared at equimolar monomer feed by solution copolymerization in the presence of a radical initiator. The order of relative reactivity (1/r ₁) was 2,5-difluoro (2.11) > 2,6-difluoro (1.84) > 3,5-difluoro (1.71) > 2,4-difluoro (1.4) > 3,4-difluoro (0.65) > 2-chloro-6-fluoro (0.59). The copolymers were characterized by IR, ¹H and ¹³C NMR, GPC, DSC and TGA. High glass transition temperatures of the copolymers compared that of polystyrene indicates a substantial decrease in chain mobility of the copolymers due to the high dipolar character of the trisubstituted ethylene monomer unit. Received: 12 June 2000/Revised version: 12 September 2000/Accepted: 12 September 2000     

Radical polymerization and copolymerization behavior of 1-cyanoethanoyl-4-acryloylthiosemicarbzide

1-Cyanoethanoyl-4-acryloylthiosemicarbazide (CEATS) was synthesized for the first time as a new chelating monomer. Its structure was confirmed by both elemental and spectral analyses. Radical polymerization and copolymerization of CEATS was been carried out in dimethylformamide (DMF) in the presence of azobisisobutyronitrile (AIBN) as an initiator. Kinetic studies for the polymerization behavior of CEATS were performed. The complex formation of the CEATS monomer and polymer (PCEATS) with Cu II cation was investigated and its stability constant determined. The rate of copolymerization of CEATS with some conventional monomers, namely vinyl acetate, methyl methacrylate and acrylonitrile, was measured as a function of the mole fraction of the monomers. The reactivity ratios (r₁, r₂) for the various copolymer systems investigated together with the Q and e values of the CEATS monomer were determined. Moreover, the thermal gravimetric analysis of the prepared polymers and their copolymers with acrylonitrile were also studied.     

Free radical copolymerization and kinetic treatment of styrene with N-phenylmaleimide

The copolymerization of styrene (M₁) with N-phenylmaleimide (M₂) in chloroform with 2,2′-azobis(isobutyronitrile) as an initiator was investigated. The kinetic parameters, such as reactivity ratios, overall activity energy, and the effect of molar fraction of monomers on the initial copolymerization rate, were determined. The bimolecular termination of the copolymerization was proved. The treatment method proposed by Yoshimura and colleagues was used to estimate quantitatively the contribution of the charge-transfer complex (CTC) and the free monomers in the copolymerization process. The propagation reactivity ratios of CTC and free monomers were calculated by a new method. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 1535–1542, 1997     

Cyclodextrins in polymer synthesis: Influence of methylated β-cyclodextrin as host on the free radical copolymerization reactivity ratios of hydrophobic acrylates as guest monomers in aqueous medium

Summary Methylated (β-cyclodextrin (me-β-CD) was used to complex the hydrophobic monomers n-butyl acrylate (1), n-hexyl acrylate (2) and cyclohexyl acrylate (3) yielding the corresponding water soluble host/guest complexes 1a–3a. The complexes were copolymerized in water by free radical mechanism and the reactivity ratios were determined by measuring the monomer consumption by HPLC. The following reactivity ratios were found: copolymerization of 1a and 2a: r₁= 1.01 ± 0.01; r₂= 1.04 ± 0.01; copolymerization of 3a and 2a: r₁= 0.74; r₂= 1.28; copolymerization of 3a and 1a: r₁= 0.75 ± 0.04; r₂= 1.13 ± 0.01. In contrast to that, the copolymerization of the uncomplexed monomers 1–3 in organic medium (DMF/H₂O) leads to nearly ideal statistical copolymers in all cases. Received: 28 November 2000/Accepted: 12 January 2001     

Salt effect on cationic copolymerization between cis-and trans - ethyl propenyl ethers

In order to study the common-ion effect on monomer reactivity ratios, cationic copolymerization between cis- and trans-ethyl propenyl ethers was carried out at 0°C by using iodine or acetyl perchlorate as initiator. In toluene, the cis isomer was several times more reactive than the trans isomer regardless of the kind of initiators employed. When a common-ion salt (tetra-n-butylammonium iodide, triiodide, or perchlorate) was added to the copolymerization system in ethylene dichloride, the monomer reactivity ratios were changed approaching those observed in a non-polar solvent such as toluene. On the other hand, in nitroethane the monomer reactivity ratios were only slightly affected by the addition of common-ion salts. These noticeable common-ion effects on monomer reactivity ratios in the ‘cis-trans’ copolymerization were satisfactorily explained on the basis of the steric hindrance between the substituents of monomers and a bulky propagating chain end.     

Polycarboxylate superplasticizers of acrylic acid–isobutylene polyethylene glycol copolymers: monomer reactivity ratios,copolymerization behavior and performance

Acrylic acid–isobutylene polyethylene glycol (AA-TPEG) copolymers are typical of polycarboxylate superplasticizers (PCEs). AA-TPEG copolymers are prepared via free-radical polymerization with potassium persulfate as the initiator. The obtained copolymers were characterized by gel permeation chromatography (GPC) and infrared spectra (FTIR). The GPC method can break through the former limitations of the instruments and receive instantaneous unreacted and instantaneous monomer concentrations and not the initial monomer feeds. Since TPEG monomer is highly bulky, the common calculation methods for determining monomer reactivity ratios in copolymerization based on terminal copolymerization equation are not suitable. However, this study created non-linear least squares curve fitting of terminal copolymerization equation (NLLSQ-T) and penultimate copolymerization equation (NLLSQ-P) methods, which used Python’s NumPy, SciPy, and SymPy libraries to generate code and did numerical computations, bringing greater accuracy of monomer reactivity ratios. The monomer reactivity ratios were calculated with Fineman–Ross, Kelen–Tüdös, YBR, NLLSQ-T, and NLLSQ-P methods and found to be r _AA = 10.888, r′ _AA = 1.131, r _TPEG = 0.012, and r′ _TPEG = 0.042 for AA-TPEG copolymers. Moreover, this study also explored specific copolymerization behavior of similar structure of copolymers with steric hindrance under penultimate copolymerization equation, such as dependence of the mole fractions in the copolymer on the mole fractions of unreacted monomers in solution, variation of copolymer compositions with conversion and sequence length distribution. The fluidity and flow loss of pastes containing PCEs were investigated, and the appropriate PCEs dosages resulted in a better workability of cement pastes.     

Electrospun poly(L-lactic acid) fiber mats containing a crude Garcinia cowa extract for wound dressing applications

The copolymerization of sodium-2-acrylamido-2-methylpropane sulfonate with acrylonitrile and acrylamide in water has been studied at different concentrations of monomers, the initiator and the external electrolyte (NaCl). It was shown that an increase in the total concentration of the monomers leads to enriching the copolymers with units of the ionic monomer. A decrease in the initiator concentration causes the increase of the nitrile content in the product. Using of reactivity ratios r₁ and r₂ was shown to be invalid for this system as it does not allow one to appropriately predict the copolymer composition or its microstructure. The observed effects of significant dependence of copolymers composition on these factors have been explained by the influence of prepolymerization processes of formation of monomer assemblies and aggregates of monomers with growing macroradicals.     

Semicontinuous emulsion copolymerization of acrylonitrile,butyl acrylate,and styrene

Semicontinuous emulsion copolymerization of acrylonitrile (M₁), butyl acrylate (M₂), and styrene (M₃) was investigated. The copolymerization proceeded under the conditions used with a high degree of conversion, whereby a stationary state characterized by a constant monomer mixture composition and a constant composition of the arising copolymer was achieved. From the analytically estimated free monomers and arising copolymer compositions, the reactivity ratios for the pair AN/BA r₁₂ = 0.71, r₂₁ = 1.17 and for the pair AN/Sty r₁₃ = 0.06, r₃₁ = 0.28 were calculated. The applicability of the reactivity ratios found was verified also for the ternary system acrylonitrile/butyl acrylate/styrene.     

Study on monomer reactivity ratios of acrylonitrile/itaconic acid in aqueous deposited copolymerization system initiated by ammonium persulfate

A single water-soluble initiator-ammonium persulfate (APS), not containing alkali metal ions, was first utilized to initiate copolymerization of acrylonitrile (AN)/itaconic acid (IA) in aqueous deposited copolymerization system. Monomer reactivity ratios of this polymerization system were investigated using element analysis method and Q–e schemes. It was found that the monomer reactivity ratios of AN/IA calculated from Q–e schemes are 0.505 (r _AN) and 1.928 (r _IA), while the monomer reactivity ratios of AN/IA in aqueous deposited copolymerization system at 60 °C are 0.64 (r _AN) and 1.37 (r _IA) calculated from Kelen–Tüdõs method, 0.61 (r _AN) and 1.47 (r _IA) from Fineman–Ross method. The three pairs of monomer reactivity ratios are in good agreement. With the increase of the polymerization temperature, the monomer reactivity ratios of AN and IA approach to unity, indicating that the aqueous deposited copolymerization of AN/IA has a tendency to ideal copolymerization. At lower polymerization conversion, the monomer reactivity ratios of AN and IA have hardly any changes. When the polymerization conversion is more than 5%, the monomer reactivity ratio of AN increases, while that of IA decreases.     

Radical copolymerization of N-vinyl-t-butylcarbamate

Summary The radical copolymerization of N-vinyl-tert-butylcarbamate (NVTBC) with styrene, methyl methacrylate, vinyl-pyrrolidone and 4-vinyl-pyridine was studied at 50–60° C in toluene, methanol or dioxane, using azo- bis- isobutyronitrile as the initiator. The reactivity ratios of the monomers were calculated from monomer feed and copolymers composition data using the Fineman-Ross method.The copolymers were hydrolysed in CH₃COOH/HCl mixtures at room temperature in order to obtain vinylamine containing copolymers. The extent of the solvolysis is dependent on the nature of the comonomer.The solvolysed copolymers bearing NH₂ groups were titrated by HCl in 2M NaCl medium in order to have more informations on the repartition of the NVTBC residues.