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In this work, the authors found that thiol is capable of initiating the copolymerization of methyl methacrylate (MMA) and acrylonitrile (AN) at room temperature. The copolymerization kinetics, copolymer composition and molecular weight of the copolymer were studied. The apparent activation energy of the overall copolymerization was measured to be 143kJ/ mol.

Glass transition temperatures are reported for copolymers of acenaphthylene with the following comonomers: methyl meth-acrylate, styrene, maleic anhydride, diethyl maleate, N-vinyl-pyrrolidone, a-methylstyrene, and trans-stilbene. The data are discussed in terms of previously published treatments of the dependence of glass transition temperature on copolymer composition. The drop in glass transition temperature consequent upon incorporation of small quantities of comonomer is not related to the glass transition temperature of the corresponding homopolymer.

The copolymerization of glycidyl methacrylate with styrene was carried out in bulk by free-radical initiation. The composition of the copolymers were determined by 1H-NMR, IR, and chemical analysis. The monomer reactivity ratios were calculated by the YBR method from the copolymer composition data. The values obtained for different techniques were compared.

The free radical copolymerization of methyl acrylate (MA) with N-phenylmaleimide (NPMI) and N-p-tolylmaleimide (NPTMI) at 75° C in cyclohexanone solution initiated by AZBN was studied. The copolymer composition has been calculated from the nitrogen content estimated by the micro-Kjeldahl's method and by NMR spectral studies. The reactivity ratios have been calculated by Mayo and Lewis, Fineman and Ross, Glen and Tudos, and Joshi and Joshi methods. Q and e values of NPMI and NPTMI were also calculated. Since the reactivity ratios are the measure of distribution of monomer units in a copolymer chain, the values obtained are compared and discussed.

If copolymerizations are carried to high conversions, the determination of copolymerization parameters involves significant computational difficulties because the exact integrated form of the copolymerization equation has to be applied. A simple method has been developed to transform experimental data, even at high conversions, to be used in the differential form of copolymerization equation. In this method an average monomer composition is assigned to the corresponding experimental average copolymer composition. The proposed approximation extends the use of our linearization technique previously developed for low conversions. It was established that this method yields highly reliable results for practically.

Infrared spectroscopic analysis was used in the determination of the copolymer composition of itaconic anhydride copolymers. The results are in close agreement with those obtained by elemental analysis. The method is of great value in determining the composition of copolymers which contain strongly absorbing groups and the composition of which could not be realized by using elemental analysis.

The Monte Carlo models of binary irreversible copolymeriza-tion with ultimate and penultimate effect are applied to the copolymerization of acrylic acid and methyl acrylate, and styrene and benzylidene malononitrile, respectively. The agreement with available experimental data is quite good. A comparative study between the formal kinetics model and the Monte Carlo model reveals that statements concerning the copolymer composition are robust, but statements concerning the sequence distribution are not always robust.

Literature copolymer composition data on the bulk polymerizations of maleic anhydride-styrene, acrylonitrile-styrene, and fumaronitrile-styrene have been considered in terms of the complex participation model. An assessment has been made in each case as to whether sequence information would be able to distinguish between the complex and penultimate polymerization models.

2-Hydroxypropyl methacrylate (2-HPMA) has been copolym-erized with ethyl methacrylate (EMA), n-butyl methacrylate (BMA), and 2-ethylhexyl methacrylate (EHMA) in bulk at 60°C using benzoyl peroxide as initiator. The copolymer composition has been determined from the hydroxyl content. The reactivity ratios have been calculated by the Yezrielev, Brokhina, and Raskin method. For copolymerization of 2-HPMA (M1) with EMA (M2), the reactivity ratios are r1 = 1.807 ± 0.032 and r2 = 0.245 ± 0.021; with BMA (M2) they are n = 2.378 ± 0.001 and r2 = 0.19 ± 0.01; and with EHMA the values are r1 = 4.370 ± 0.048 and r2 = 0.103 ± 0.006. Since reactivity ratios are the measure of distribution of monomer units in copolymer chain, the values obtained are compared and discussed. This enables us to choose a suitable copolymer for synthesizing thermoset acrylic polymers, which are obtained from cross-linking of hydroxy functional groups of HPMA units, for specific end-uses.

A new graphically-evaluable linear method is suggested for the determination of the reactivity ratios of copolymerization. The proposed new equation is very well adaptable for visual determination of the applicability of the copolymer composition equation. If the experimental data are adequate to the composition equation, the procedure offers a simple and reliable method for the graphical determination of copolymerization constants.

Improved correlation between glass transition temperatures and copolymer composition was obtained in styrene-methyl methacrylate copolymers by assessing contributions of triad rather than diad concentrations. Contributions of ABA and BAB triads were found to be significantly different. Glass transition temperature minima as a function of copolymer composition were found to be related to the solubility parameters (and cohesive energy densities) of the parent homopolymers.

The penultimate effect in the radical copolymerization of vinyl chloride (C) and vinylidene chloride (V), described in a previous paper, is interpreted in terms of head-to-head addition of a V molecule to a C-ended radical. The later is estimated from NMR analysis of the copolymer. It occurs about three times faster than the corresponding head-to-tail addition. It is shown that both the penultimate effect model and the “head-to-head assumption” lead to the same values for either the copolymer composition or several functions of the sequence distribution. It is further suggested that the head-to-head addition is possible owing to the propagation-depropagation equilibrium for the V-ended radical and to the very high reactivity of the tail radical produced.

A new reduced copolymer composition equation weighing the effects of units through the antepenultimate is derived for the first time. The simplification obtained is placed into context with previously published work.

A method is outlined for the calculation of azeotropic compositions in ternary copolymerization. The results of these calculations are consistent with those reported by Tarasov et al. (2), and with those calculated by a recent method developed by L. J. Young of the Dow Chemical Company. Our results are further checked with the calculated monomer/copolymer composition during the predicted azeotropic copolymerizations. It was found, in all cases, that the monomer/copolymer composition stays constant, as expected. A method of graphical extrapolation is introduced for estimating the azeotropic composition when some reactivity ratios are inaccurate.

Tetrahydronaphthoquinone (THNQ) and dimethyl tetrahydronaphthoquinone (DMTHNQ) were found by UV spectroscopy to form donor-acceptor complexes with divinyl ether (DVE), the latter being the electron donor. Since the participation of such complexed species has been considered in the cyclocopolymerization of a 1,4-diene with a monoolefin such as DVE-maleic anhydride (MA) and DVE-fumaronitrile (FN) systems, radical copolymerization of THNQ and DMTHNQ with DVE was studied. It was found that these copolymers have constant 1:1 composition regardless of the feed composition. The terpolymerization of DVE-THNQ-DMTHNQ confirmed the 1:1 donor-acceptor composition in the polymer. The integration of the NMR spectrum was used in determining the copolymer composition. The spectroscopic data suggest a cyclized repeating unit in which the copolymer main chain consists of only DVE units. There is a marked difference between these copolymers and the typical cyclo-copolymers, such as DVE-MA and DVE-FN, in which the c...

In order to clarify the effects of the sulfur atom and the alkyl groups in alkyl vinyl sulfides (RVS) on their reactivities, the radical copolymerizations of eight RVS (M2) with styrene, methyl methacrylate, and acrylonitrile (Mi) were investigated at 60°C, and the copolymerization parameters were determined. It was found that the Q and e values for RVS were estimated as 0.3 ∼ 0.5 and -1.1 ∼ -1.7, respectively, from the copolymerizations with styrene, and these values were almost unchanged, regardless of the type of alkyl group in RVS. These results indicated that the electron-sharing, 3d orbital resonance between the growing radical derived from electron-donating RVS monomer and the adjacent sulfur atom was important in the transition state of copolymerizations. It was also found that the copolymer composition curves in the copolymerizations of RVS varied widely with the comonomers used, and the tendency for alternative copolymerizations increased with an increase in the electron-accepting natur...

Styrene and α-methylstyrene have been copolymerized at 60°C. At this temperature depropagation of the latter monomer must be considered. The rate of copolymerization and the chain length of the polymer formed are quantitatively interpreted by an extension of the theory previously used to describe the copolymer composition. It is postulated that rapid termination of copolymerization occurs because of the presence in the systems of low molecular weight free radicals of poly(α-methylstyrene) of chain length 3 cr less.

Free-radical copolymerizations of styrene with α-methylstyrene and methyl methacrylate and of acrylonitrile with α-methylstyrene have been carried out in the approximate regions of the ceiling temperatures of α-methylstyrene and methyl methacrylate. A theoretical treatment of copolymerization emphasizing the thermodynamic reversibility of particular propagation reactions has been compared with a kinetic treatment of copolymerization which emphasizes penultimate unit effects on the same propagation reactions. The former is found to adequately describe experimental copolymer composition data over a wide range of temperatures and over the complete range of monomer feed composition.

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.