Radical Copolymerization Of Methyl Methacrylate Research Articles

Effect of imidazolium‐p‐chlorophenacylide on the radical copolymerization of methyl methacrylate with styrene

AbstractRadical copolymerization of methyl methacrylate with styrene using imidazolium‐p‐chlorophenacylide (ICPY) as accelerator in the presence of AIBN resulted in alternating copolymers as evidenced by NMR spectroscopy. The rate of copolymerization is a direct function of [ICPY], [MMA] and polymerization temperature, but [St] has an inverse effect. The accelerating effect is due to increase of rate of initiation. The ylide does not effect average degree of polymerization.

Determination of the mode of termination in free‐radical copolymerization

AbstractIn this study the apparent rate constant model was used to determine the mechanism of termination and other rate constants for free radical copolymerizations that are chemically controlled with no penultimate effect. The data required were the number average molecular weight and the conversion obtained at various initial initiator concentrations and monomer compositions, and two rate constants of propagation of the homopolymerizations of its two monomers. The bulk free radical copolymerization of methyl methacrylate (MMA) and styrene(St) at 60°C was studied. Three published literature values of the propagation rate constants k11 and k22. 750, 150; 515, 145; 705, 145, were used for the determination. The unit of the rate constants used was liter/mole/s. The modes of the termination reaction obtained, depending on k11, k22 used, are given as follows: mole percent Combination in the Termination (k11, k22) MMA‐MMA radicals St‐St radicals St‐MMA radicals (750, 150) 17 99 96 (515, 145) 54 99 91 (705, 145) 40 98 87 The modes of termination obtained by the case of k11 = 750 and k22 = 150 are in good agreement with those shown by Bevington, Melville, and Taylor (1).

Kinetics of crosslinking reactions. 1. Reaction rate of intramolecular crosslinkings by using a soluble microgel

AbstractSoluble microgels with several pendant vinyl groups were synthesized by radical copolymerization of methyl methacrylate (MMA) with p‐divinyl benzene (p‐DVB). The polymerization conditions used for intramolecular crosslinking of microgels were chosen from gel permeation chromatograph (GPC) measurements of the reaction products. The rate constant of intramolecular crosslinking (kpi) was estimated from the changes in the concentration of pendant vinyl groups of microgel by using photometrical measurements at 30°C assuming a unimolecular termination mechanism of polymer radicals. As a result, kpi showed larger values than kp of styrene and depended strongly on the internal structure of the microgels.

An investigation of the kinetics of copolymerization of methyl [formula omitted] styrene to high conversion: Modelling diff″sion-controlled termination and propagation by free-volume theory

An experimental investigation of the kinetics of the free radical copolymerization of methyl methacrylate (MMA) and p-methylstyrene (PMS) initiated with azobisisobutyronitrile (AIBN) was conducted at temperatures of 60°C and 80°C. Three levels of initiator concentration and initial monomer composition were studied. Conversions were measured gravimetrically and by gas chromatography (g.c.) and the weight average molecular weight ( M ̄ w ) by low-angle laser light scattering photometry (LALLSP). A kinetic model using free volume theory seems adequately to account for diffusion-controlled termination and propagation. The model also accounts for segmental-diffusion control of termination at low conversions and termination by reaction diffusion at high conversions. Model predictions are in reasonable agreement with published data on homopolymerization of MMA (ref. 1) as well as with data on copolymerization of these monomers reported herein. This model should find use in the design, simulation, optimization and control of polymer reactor systems for the production of MMA/PMS copolymers.

Effect of thermodynamic strength of solvent on structure formation of crosslinked copolymers

AbstractThe effect of the thermodynamic strength of the solvent used in the copolymerization of mono‐ and bifunctional monomers on the molecular‐topologic structure of soluble copolymers with bridge bonds was investigated. The investigation was carried out taking as an example radical copolymerization of methyl methacrylate (MMA) and 9,10‐anthrylenedimethyl dimethacrylate. The presence of anthracene groups in the molecules of the crosslinking agent made it possible to follow the number of intra‐ and interchain bridge bonds formed in the polymer system. Toluene/octane mixtures with an octane content from 0 to 35 vol.‐% were used as solvents of different thermodynamic strengths with respect to PMMA. It was found that over a narrow range of changes in the composition of the solvent (from 30 to 33 vol.‐% of octane) the values of M̄n and [η] of the copolymers increase drastically. It is shown that this increase is due to an increase in the number of interchain crosslinks occurring when the strength of the solvent under the copolymerization conditions used decreases.

Radical polymerization in the presence of complexing agents. V. Effect of low concentration of ZnCl2 on the radical copolymerization of methyl methacrylate with ethyl acrylate

AbstractReactivity ratios for the free‐radical copolymerization of methyl methacrylate with ethyl acrylate in the presence of low concentrations of ZnCl2 are analyzed at different polymerization temperatures, 35,50, and 65°C. The different tendencies of the two monomers toward the formation of molecular complexes with the metal halide modify the homopropagation and cross‐propagation coefficients and the results obtained seem to indicate a conventional cross‐propagation mechanism in which both free and complexed species of acrylic monomers participate.

The effect of temperature on the free radical copolymerization of methyl methacrylate with ethyl acrylate

Methyl methacrylate has been copolymerized with ethyl acrylate at temperatures between 35 and 65′ using 2,2′-azo bisisobutyronitrile as initiator. For both polymer radicals, crosspropagation is favoured energetically whereas self-propagation is favoured entropically. Values of Arrhenius parameters indicate that cross-propagation predominates for ethyl acrylate and self-propagation for methyl methacrylate.

Effect of solvent on the termination step for the radical copolymerization of methyl methacrylate and styrene

The kinetics of the radical copolymerization of methyl methacrylate and styrene in benzene, chlorobenzene and benzonitrile has been investigated gravimetrically. The copolymerization termination step is analysed on the basis of the chemically controlled model, the diffusion-controlled model and the combined physical and chemical model, taking into account the corresponding reactivity ratios and the homopolymerization parameters in the three solvents used. The values obtained for the termination step parameters suggest that the termination step might be controlled by the viscosity of the reaction medium, but the sequence distribution and the stereochemical configuration of the polymer chains must also be considered.

Configuration of methyl methacrylate-2-naphthyl methacrylate copolymers

Radical copolymerization of methyl methacrylate (MMA,M1) with 2-naphthyl methacrylate (2NM,M2) is characterized by the reactivity ratios: $$\begin{gathered} r_1 = 0.33 \pm 0.08 \hfill \\ r_2 = 1.93 \pm 0.16. \hfill \\ \end{gathered}$$

Radical Copolymerization of Methyl Methacrylate with Styrene in Several Solvents

Abstract Radical copolymerization of styrene (M1) with methyl methacrylate has been carried out in several solvents. The monomer reactivity ratio (r) was affected by the solvent. The values of log 1/r, Q2, and e2 were found to increase with the decreases of the V C[dbnd]O and v n[dbnd]c stretcning frequencies determined in the corresponding solvents.

Radical Copolymerization of Acrylic Monomers. I. Effect of Solvent on the Copolymerization of Methyl Methacrylate and 1-Naphthyl Methacrylate

Abstract A study of the radical copolymerization of methyl methacrylate and 1-naphthyl methacrylate in benzene, chlorobenzene, and o-dichlorobenzene was made at 50°C. There is a marked effect of solvent on both r1 and r2 in all these systems, which can be correlated with the variation in the polarity of solvents. The glass transition temperatures of copolymers were discussed taking into consideration the sequence distribution of the copolymers and the homopolymers tg - values.

Radical Copolymerization of Acrylic Monomers. II Effect of Solvent on Radical Copolymerization of Methyl Methacrylate and Styrene

Abstract The influence of various solvents on the copolymerization behavior of methyl methacrylate with styrene has been investigated. In these systems there is a significant solvent effect on both rS and rM which may be attributed to changes in the dielectric constant of the solvents used. The calculated relative reactivity of the polystyryl radical towards the methyl methacrylate monomer increases with increasing solvent polarity, whereas the reactivity of poly(methyl methacrylate) radical towards styrene monomer decreases. The results obtained are discussed taking into account the behavior of both monomers in homopolymerization with the same experimental conditions as in copolymerization.

Mechanism of the Radical Copolymerization of Methyl Methacrylate and Maleic Anhydride

Abstract The kinetics of the copolymerization of methyl methacrylate and maleic anhydride was investigated in benzenic solutions at 60 and 70° C and in bulk at 60°C. The microstructure of the copolymers was determined by 1H-NMR and IR spectrophotometry. In benzene solutions the mechanism of copolymerization involves the participation of an associative species between both comonomers. In bulk a terminal model is sufficient to explain all the results.

Determination of assigned configurational parameters for cross propagation in radical copolymerization of methyl methacrylate and trityl methacrylate

Copolymer of methyl methacrylate-d8(M1) with a small amount of trityl methacrylate(M2) was radically prepared in tetrahydrofuran and converted into the copolymer of methyl methacrylate-d8 with a small amount of undeuterated methyl methacrylate by the selective hydrolysis of the trityl group and subsequent methylation with diazomethane. From the 1H NMR spectrum of the derived copolymer the assigned coisotactic parameters σ12 and σ21 were determined to be 0.14 and 0.61, respectively. This may be the first example of the unequivocal determination of assigned configurational parameters in cross propagation for copolymerization.

Influence of applied electric fields on the free radical copolymerization of methylmethacrylate and styrene. An unusual decomposition of benzoylperoxide

The influence of an applied electric field on the free radical copolymerization of methylmethacrylate (MMA) and styrene (ST) in benzene solution was investigated. With benzoylperoxide as initiator, retardation of the polymerization of MMA was observed in the cathode compartment, whereas the polymerization of ST and the copolymerization of MMA and ST in the anode compartment were unaffected. No such effects were found when azobisisobutyronitrile was the initiator. The effect of the electric field on the polymerization of MMA was attributed to the effect of oxygen formed at the cathode by decomposition of benzoylperoxide in an electrolytic redox reaction that also produced [graphic omitted] and [graphic omitted] together with the products of the thermal decomposition.

Solvent effects on radical copolymerization of methyl methacrylate and acrylonitrile

AbstractRadical copolymerization of methyl methacrylate and acrylonitrile has been studied in six solvents at 60°C, and two monomer feed ratios. The nitrogen contents of the copolymers increases in the order: chloroform < dioxane < benzene < anisole < methyl pentyl ketone < bromobenzene, suggesting an influence of the solvent on the growing radicals.

Copolymerization of diphosphonbutadienes with methyl methacrylate and styrene

The radical copolymerization of methyl methacrylate and styrene with diphosphonbutadienes has been studied. The basic rules for the copolymerization process have been established and the relative activities of the copolymers investigated have been determined, as well as the specific activity Q and the polarity factor e of the diphosphonbutadienes. The chain transfer constants for the polymerization of methyl methacrylate in the presence of monomers containing phosphorus have been found. Certain properties of the copolymers containing phosphorus have been studied.

Solvent Effect in Radical Copolymerization of Methyl Methacrylate with Styrene

Abstract A study of the copolymerization of methyl methacrylate and styrene in monosubstituted benzenes such as benzene, benzonitrile, benzyl alcohol, and phenol was made at 60°C. It was found that the copolymerization parameters changed significantly with the polarity of solvents, and the relative reactivity of methyl methacrylate toward the polystyryl radical was correlated with the ET values of solvents. These results and spectroscopic data suggest that in the transition state of this copolymerization the polarized structure of methyl methacrylate monomer became important, enhancing its reactivity, as the solvents became more protic.

Solution properties of copolymer of p‐chlorostyrene and methyl methacrylate

AbstractThe monomer reactivity ratios in the free radical copolymerization of methyl methacrylate and p‐chlorostyrene were obtained and an azeotropic copolymer containing the 0.484 mole fraction of methyl methacrylate was prepared. The copolymer was fractionated into nine fractions, which on the basis of their chlorine content and specific refractive index increments, were found to be homogeneous in their chemical composition. The solution behaviour of these fractions was examined by viscosity, osmotic pressure and light‐scattering techniques. The weight‐average molecular weights obtained in dioxane, chloroform and 78:22 v/v mixture of trans‐decalin and trichloro ethylene (Θ solvent at 22.3°C) were found to be identical but those obtained from benzene were as much as 80% higher, depending on the molecular weight. The data were treated by the method of STOCKMAYER and BENOIT and the deviation and square‐deviation of the chemical composition was obtained as zero and proportional to M1.5, respectively. The value of exponent “a” in the KUHN‐HOUWINK equation[η] = KMa obtained by use of the number‐average molecular weight and corrected weight‐average molecular weight, was identical but the apparent weight‐average molecular weights obtained in benzene gave a low value of “a” confirming the applicability of the STOCKMAYER‐BENOIT relationships. The value of the constant K obtained for the copolymer in the theta solvent was 6.4·10−4 compared with 4.9·10−4 and 5.0·10−4 obtained for poly(methyl methacrylate) and poly‐p‐chlorostyrene, respectively, indicating a 10% higher dimension for the copolymer.