Values Of Monomer Reactivity Ratios Research Articles

Synthesis and characterization of novel methacrylate copolymers having pendant piperonyl group: monomer reactivity ratio, thermal degradation kinetics, and biological activity

In this study, 2-{[(2H-1,3-benzodioxol-5-yl)methyl]amino}-2-oxoethyl 2-methylprop-2-enoate (BMAOME) monomer was synthesized, and copolymers were prepared with glycidyl methacrylate (GMA). Structural characterizations of the compounds were performed using FTIR, 1H-, and 13C-NMR techniques. Monomer reactivity ratio values were calculated by Finemann–Ross (FR) and Kelen–Tudos (KT) methods. The Tg value of the polymers was determined by differential scanning calorimetry (DSC) and their thermal stability was determined by thermogravimetric analysis (TGA). The molecular weights (w and n) and polydispersity index of the polymers were determined by gel permeation chromatography. The Ea value of thermal decomposition was determined by using the Ozawa and Kissinger methods. The photo-stability of the copolymers was investigated. Furthermore, the photo-stability of the copolymers and the biological activity of polymers against different types of bacteria and fungi were investigated.

Markov Chain Modeling of Surfactant Critical Micelle Concentration and Surface Composition.

A Markov chain (MC) model has been used to model the following binary surfactant mixtures: linear alkylbenzenesulfonate (LAS4)/octaethylene glycol monododecyl ether (C12E8) at 10 and 25 °C, LAS6/acidic sophorolipid (AS), C12Betaine/C12Maltoside, sodium lauryl ether sulfate (SLES2)/C12E8, and rhamnolipid (R1)/LAS6. The critical micellar concentration and the composition of the adsorbed layer, for each system, can be modeled using the same monomer reactivity ratio values, g1 and g2. This implies that the interactions between the surfactants in the bulk solution and at the interface are the same, within error. For the LAS4/C12E8 system at 25 °C, the ranges of g1 and g2 values which can model both sets of data are within 0.03-0.05 and 1.55-2.10, respectively; g1 ≪ g2 implies that C12E8 is significantly more surface active than LAS4. The MC model indicates a negative change in the free energy upon mixing for all of the surfactant systems, consistent with the literature. The interfacial mixing behavior of LAS4/SLES2 is inferred from the results of the MC analysis of the LAS4/C12E8 and SLES2/C12E8 systems, which share a common surfactant partner in C12E8, and the prediction is in line with the published data.

Free Radical Copolymerization of Methyl Methacrylate and Styrene with N-(4-Carboxyphenyl)maleimide

The free radical copolymerization of methyl methacrylate (MMA) or styrene (St) with N-(4-carboxyphenyl)maleimide (CPMI) was carried with AIBN as an initiator in THF solvent at 80°C. A series of copolymers of MMA and St with CPMI were prepared using different feed ratios of comonomers. The values of monomer reactivity ratios (r1, r2) determined by Fineman-Ross and Kelen-Tudos methods are 0.26 and 2.51 in the CPMI/MMA system and 0.08 and 0.22 in the CPMI/St system. Alfrey–Price Q-e values for CPMI were calculated as Q = 1.05 and e = 0.41 in the CPMI/MMA system and Q = 1.21 and e = 0.91 in the CPMI/St system. The polymer samples have been characterized by solubility tests, intrinsic viscosity measurements, FT-IR and 1H-NMR spectral analysis, and thermo-gravimetric analysis. It was found that the initial and final decomposition temperatures increased with increasing the amount of CPMI in the copolymer. The integral procedural decomposition temperature and energy of activation of thermal degradation have also been reported.

Radical polymerization of N-(4-butoxycarbonylphenyl)maleimide, its co-polymerization with methyl methacrylate, styrene and acrylonitrile, and the properties of the resulting polymers

Co-polymers were synthesized from free radical co-polymerization of methyl methacrylate (MMA), styrene (ST) and acrylonitrile (AN) with N-(4-butoxycarbonylphenyl)maleimide (BCPM), using benzyl peroxide (BPO) as an initiator and DMF as a solvent at 85°C. A series of co-polymers of MMA, ST and AN with BCPM was prepared using different feed ratio of comonomers. The thermo-stabilities and physical properties of the polymer samples obtained have been described. The values of monomer reactivity ratios r 1 and r 2 determined by Fineman–Ross and Kelen–Tudos methods are 0.28 and 0.90 in BCPM/MMA, 0.20 and 0.39 in BCPM/ST and 0.51 and 1.23 in BCPM/AN systems. Alfrey–Price Q and e values for BCPM are Q = 1.39 and e = 1.57 in BCPM/MMA, Q = 2.53 and e = 2.15 in BCPM/ST and Q = 1.11 and e = 1.89 in BCPM/AN systems.

Synthesis and Radical Polymerization of N‐[4‐N′‐(Phenylamino‐carbonyl)phenyl]maleimide and its Copolymerization with Methyl Methacrylate

A novel type of imide‐amide monomer, 4‐maleimidobenzanilide (MB) i.e., N‐[4‐N′‐(phenylaminocarbonyl)phenyl]maleimide was synthesized from maleic anhydride, p‐aminobenzoic acid and aniline. Radical polymerization of MB and its copolymerization with MMA (methyl methacrylate), initiated by AIBN, were performed in THF solvent at 65°C. Nine copolymer samples were prepared using different feed ratios of comonomers. All the polymer samples have been characterized by a solubility test, intrinsic viscosity measurements, FT‐IR and 1H‐NMR spectral analysis, and thermo‐gravimetric analysis. The values of monomer reactivity ratios of MB‐MMA system (r1, r2) and the Alfrey‐Price parameters Q1 and e1 were determined.

Gradient or statistical copolymers by batch nitroxide mediated polymerization: effect of styrene/methyl acrylate feed

Monomer reactivity ratios in controlled radical copolymerization of styrene (S) and methyl acrylate (MA) monomers at 120 °C were determined. The Fineman–Ross method was used to calculate rs and rMA. Using this method, monomer reactivity ratio values of 0.89 and 0.22 were calculated for styrene and methyl acrylate, respectively. Because of the different reactivity ratios between the two monomers, and according to the molar fractions of two monomers, S/MA statistical or gradient copolymers were synthesized by nitroxide-mediated polymerization. Indeed, for different monomer ratios, the same statistical or gradient copolymers can be obtained by batch nitroxide mediated polymerization. These copolymers have been characterized by 1H nuclear magnetic resonance and size exclusion chromatography, and evolution of the composition has been correlated with the glass transition temperature measured by differential scanning calorimetry. Integrated intensities of the three observed peaks of (–OCH3) group in the 1H NMR spectra were used to determine the MA/MA/MA, MA/MA/S and S/MA/S triad sequences in the copolymers. Specific organization at the air/polymer interface of such copolymers has also been demonstrated by comparison between classical and attenuated total reflection (ATR) Fourier transform infra-red spectra.

High temperature copolymerization of styrene/ethyl acrylate: Reactivity ratio estimation in bulk and solution

AbstractStyrene/ethyl acrylate (Sty/EA) free‐radical copolymerizations have been conducted in bulk with and without initiator and in solution using p‐xylene and m‐xylene (30 wt% and 60 wt% solvent level) at 100°C and 130°C. The monomer reactivity ratio values and their temperature dependence have been determined from low conversion copolymer composition data using the computer software package RREVM, which is based on the error in variables model (EVM) method. Copolymer composition data at low conversion confirmed the Mayo–Lewis model at both temperatures. The reactivity ratio values of the Sty/EA system do not seem to change with dilution by nonpolar solvents at low concentration from the reactivity ratio values obtained in bulk with and without initiator. However, xylene isomers were found to have a slight effect on the reactivity ratio value of ethyl acrylate when high solvent concentration was utilized. © 2004 Wiley Periodicals, Inc. Adv Polym Techn 23: 186–195, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20009

Estimation of monomer reactivity ratios in free‐radical solution copolymerization of lauryl methacrylate–isobutyl methacrylate

AbstractCopolymers of isobutyl methacrylate (i‐BMA) and lauryl methacrylate (LMA) were prepared by free‐radical solution copolymerizations at 70 °C with azobisisobutyronitrile (AIBN) as an initiator. The synthesis of these copolymers was investigated over a wide composition range both at low and high conversion levels. Copolymer compositions were determined from the %C, %H, and %O contents of copolymer by elemental analysis. Monomer reactivity ratios were estimated by analyzing composition data with nonlinear least‐squares (NLLS) models based on Marquardt optimization and van Herk methods. The point estimates, 95% individual confidence intervals and 95% joint confidence intervals are obtained from differential and integral approaches. Even though no explicit integral form for penultimate unit model (PUM) is available, a numerical approach is developed for integral estimation of reactivity ratios from PUM. A simulator program was developed which upon coupling of experimental data, NLLS analysis, and D‐optimal criteria calculates the best optimized values of monomer reactivity ratios and monomer feed compositions in a sequential and iterative order for terminal and penultimate unit models. Moreover, the simulator has the capibilities to calculate all features of van Herk method, maximum compositional drift in each monomer feed composition, and data reconciliation. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 112–129, 2004

Synthesis and monomer reactivity ratios of (vinylcyclohexane-co- N-vinyl-2-pyrrolidone) copolymer

A copolymer containing vinylcyclohexane (VCH) and N-vinyl-2-pyrrolidone (VP) at different compositions was synthesized and characterized. The monomer reactivity ratios (MRR) were estimated by using the classical Fineman–Ross and Kelen–Tüdõs linear fitting methods. These parameters were also estimated using a nonlinear computational fitting procedure, known as reactivity ratios error in variable model (RREVM). In this case, the values of MRR are r VP=2.2 and r VCH=0.0. Composition shifts and MRR values for (vinylcyclohexane-co- N-vinyl-2-pyrrolidone) copolymer (VCH-co-VP) are interpreted in terms of the relative comonomeric structures. A copolymer with zones containing VP blocks with isolated units of VCH between them is obtained. The presence or absence of the resonance stabilization effect is taken into account. The results are compared with those of similar related copolymeric systems.

Free radical copolymerization of 2-hydroxyethyl methacrylate with butyl methacrylate: determination of monomer reactivity ratios and glass transition temperatures

Free radical copolymerization of 2-hydroxyethyl methacrylate with butyl methacrylate using 3.0 mol l −1 N, N′-dimethyl formamide, DMF, solution and 9.0×10 −3 mol l −1 of 2,2′ azobisisobutyronitrile, AIBN, as initiator, was carried out at 50°C. Experiments performed in bulk have evidenced the possible solvent effect in the values of monomer reactivity ratios. Besides, the homopolymers glass transition temperature, T g, the intra and intermolecular structure along with Johnston's equation have enabled describing the experimental variations of HEMA–BMA copolymers' T g.

Monomer reactivity ratios of styrene-butyl acrylate copolymers at low and high conversions

Monomer reactivity ratios in free radical copolymerization of styrene and butyl acrylate monomers at 80°C in toluene solution under reduced pressure were determined for low and high conversions. Mayo-Lewis, Finemann-Ross, inverted Finemann-Ross, Kelen-Tüdós, extended Kelen-Tüdós. Tidwell-Mortimer and Mao-Huglin methods for low conversion and extended Kelen-Tüdós and Mao-Huglin methods for high conversion were used to calculate r Sand r B in this paper. Using the Mao-Huglin method, for conversions below 15%, monomer reactivity ratio values of 0.887 and 0.216 were calculated for styrene and butyl acrylate, respectively. For conversions greater then 15%, these values were found to be 1.006 and 0.232, respectively. In addition, the reactivity ratios calculated from the second-order Markov reaction were compared with that of calculated using the first-order Markov reaction.

X-ray photoelectron spectroscopy: A new method for determination of copolymer composition, and monomer reactivity ratios and monomer sequence distribution therefrom

Copolymer compositions and reactivity ratios for the radical copolymerization of styrene with acrylonitrile have been determined by x-ray photoelectron spectroscopy (XPS). The results obtained by this technique were confirmed by elemental as well as 1H-NMR (nuclear magnetic resonance) analysis. The monomer sequence distributions have also been calculated utilizing the monomer reactivity ratio values obtained by three different techniques viz., XPS, 1H-NMR, and elemental analysis. The agreement between the monomer sequence distributions in the copolymer chain by these methods is very satisfactory. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 2049–2056, 1997

Styrene‐butadiene copolymerization initiated by organopotassium compounds in hydrocarbon medium

AbstractThe following values of monomer reactivity ratios were found: rS = 3,3 ± 0,3; rB = 0,12 ± 0,02 (cyclohexane, 25 °C). The comparison of the kinetic parameters obtained with Li, Na and K counter‐ions shows that the great difference between coordination polymerization with Li and “typically anionic” polymerization with K is mainly determined by the variation of the cross‐propagation rate constant kBS with the nature of the counter‐ion. No evidences for the specific role of the solvation of Li counter‐ion with butadiene monomer were found.

Direct polar conjugation in radical copolymerization of styrene with substituted styrenes

The electronic effects of substitutents on the values of monomer reactivity ratios in copolymerization of styrene with substituted styrenes have been isolated. The most important proved to be the direct polar conjugation of the substitutent with the nucleophilic reaction centre. A two-parameter correlation equation has been proposed which describes satisfactorily the experimentally determined reactivity of comonomers. The values of monomer reactivity ratios have been determined for copolymerization of styrene with para and meta-substituted aminostyrenes.

Estimation of copolymer composition from online headspace analysis in batch emulsion polymerization

A new method has been developed for calculating instantaneous copolymer compositions from sampled measurements of component fractions in the reactor vapor-phase by a modified online headspace technique. The methodology is successfully applied to batch emulsion copolymers of Styrene and Acrylonitrile. Reliable values of monomer reactivity ratios as well as equilibrium (L/L/V) parameters are used in the calculation.

A New Analytical Solution of the Binary Copolymer Composition Equation and Suggested Procedure for Deriving the Monomer Reactivity Ratios

Abstract An absolute analytical procedure is found for obtaining the parameters of the differential, binary, copolymer composition equation, setting up a least-squares condition that places equal weight on all experimental lines of the Mayo-Lewis plot. The values of monomer reactivity ratios for the system ethyl methacrylate (M1-vinylidene chloride (M2), studied by Agron et al., are r1 = 2.052 ± 0.043 and r2 = 0.346 ± 0.052. These values, especially r1, differ from the estimates by Agron et al. The new solution, however, appears to yield the estimate of maximum likelihood for the reactivity ratios based on the given experimental data.