Acrylonitrile-methyl Methacrylate Research Articles

Qualitative and quantitative analysis of methyl acrylate or methyl methacrylate of acrylonitrile fibers by pyrolysis gas chromatography

AbstractDegradation gases evolved from methyl acrylate or methyl methacrylate of acrylonitrile fibers were analyzed by pyrolysis gas chromatography. For determining polymer composition, optimum pyrolysis conditions were determined and calibration was accomplished by using acrylonitrile–methylacrylate and acrylonitrile–methyl methacrylate model copolymers. Out of the 23 samples examined, 10 were found to contain methyl acrylate and five methyl methacrylate comonomers, in the range of 3.5–8.0%. The reproducibility of the method was good, the coefficient of variations was ±2% for methyl acrylate and ±2.5% for methyl methacrylate. Compositions were in agreement with those determined by other methods.

Preparation of a polyacrylonitrile fiber from a mixture of an acrylonitrile-methyl methacrylate copolymer and a polyurethane

The most stable solutions of mixtures of polyacrylonitrile with polyurethane (containing the heterocyclic triazine ring in the main chain) with an optimum size of the disperse phase particles were obtained at a component ratio of 95:5.

Dilute solution properties of methyl methacrylate—acrylonitrile copolymer (MA2)

AbstractThis article deals with studies of the dilute solution properties of methyl methacrylate‐acrylonitrile (MMA‐AN) copolymer of 0.415 mole fraction (mf) of acrylonitrile composition. Mark—Houwink parameters for this copolymer have been evaluated in acetonitrile (MeCN), 2‐butanone (MEK), dimethyl formamide (DMF), and γ‐butyrolactone (γ‐BL). The Mark‐Houwink exponent a in all four solvents at all temperatures is larger than the corresponding values of the parent homopolymers. The solvent power is in the order of DMF < γ–BL < MEK < MeCN; [η] decreases with an increase in temperature, which is behavior characteristic of polymers in good solvent. The unperturbed dimensions (K0) values, obtained by the Stockmayer–Fixman method, are lower than those for the parent homopolymers and depend on solvent as well as temperature. The solute—solvent interaction parameter X1 values are close to 0.5; X1 is independent of temperature. The excess interaction parameter XABvalues are negative. The results for this copolymer system in regard to low second virial coefficient A2, large X1, and high a values suggest that the large extension of these copolymer chains is due to the unusual short‐range interactions.

Dilute solution properties of methyl methacrylate—acrylonitrile copolymer (MA1)

This paper deals with studies on the dilute solution properties of methyl methacrylate—acrylonitrile copolymer of 0.289 mole fraction ( mf) of acrylonitrile composition. Mark—Houwink parameters for this copolymer have been evaluated in acetonitrile (MeCN), 2-butanone (MEK), dimethylformamide (DMF) and γ-butyrolactone (γ-BL). The solvent power is found to be in the order of MEK < MeCN < DMF < γ-BL at 30°C. Herein, probably for the first time, the steric factor for the copolymer is found to be lower than that for the parent homopolymers and the excess interaction parameter, χ AB is found to be negative. This probably suggests that the units are compatible to each other.

Sequence Distribution in Acrylonitrile-Methyl Methacrylate Copolymers by NMR Spectroscopy : Analysis of α-Methyl Peaks

Sequence Distribution in Acrylonitrile-Methyl Methacrylate Copolymers by NMR Spectroscopy : Analysis of α-Methyl Peaks

Melt viscosity characteristics of methacrylate–styrene copolymers

AbstractThe activation energies of flow EA of methacrylate–styrene copolymers containing n‐butyl, n‐hexyl, n‐heptyl, n‐octyl, n‐decyl, n‐dodecyl, n‐tridecyl, n‐octadecyl, and cyclohexyl methacrylate have been investigated as a function of molecular weight, composition, and methacrylate monomer. Below a critical pendent group molar volume per chain unit (120 ± 10 ml Le Bas units), EA was found to increase with molar volume; and above this value, a decrease in EA was observed, reflecting a decrease in copolymer density. Copolymers with pendent group molar volumes per average chain unit of between 96 and 140 ml (Le Bas units) were found to exhibit sufficiently high EA values to render them suitable for use in thermoplastic and photothermoplastic devices with superior development and erasure rates, at temperatures which enabled the attainment of the development and erasure viscosities with a low expenditure of heat energy. Methacrylate–styrene copolymers with long‐chain ester methacrylates (viz., n‐decyl and n‐dodecyl methacrylate) were found to exhibit critical molecular weights Mc below 3000; and Mc was found to decrease with increasing methacrylate tail length and methacrylate concentration. These Mc values correspond to critical chain lengths Zc below 45. Similar Zc values have been previously reported for acrylonitrile–methyl methacrylate copolymers30 and ethylene–propylene copolymers.28

Effect of Composition on the Huggins Constant, k' for Methyl Methacrylate-Acrylonitrile Copolymers

Effect of Composition on the Huggins Constant, k' for Methyl Methacrylate-Acrylonitrile Copolymers

The Critical Miscibility Composition of Styrene-Acrylonitrile-Methyl Methacrylate Terpolymers

Abstract Ternary statistical copolymers composed of styrene, acrylo-nitrile, and methyl methacrylate were synthesized and frac-tionated by a precipitational method. For a given polymer concentration, the volume fraction of nonsolvent, i.e., methanol, at the precipitation point. γ, increases in the order: polystyrene > acrylonitrile-styrene and acrylonitrile-methyl methacrylate binary copolymers > ternary co-polymers. The γ values in methanol-dimethylformamide (DMF) mixture are larger than those in methanol-butanone, indicating that DMF is a better solvent for the terpolymer. A linear relation was obtained between the reciprocal limiting viscosity number and γ values of fractions. The dependence of γ on the terpolymer composition could not be established exactly in these systems. The temperature coefficient of γ, dγ/dT, increases with the MMA content and decreases with the styrene content in terpolymers both in butanone and in DMF mixtures.

Determination of Monomer Reactivity Ratios in Copolymerization from a Single Sample and Its Application to the Acrylonitrile–Methyl Methacrylate System

Determination of Monomer Reactivity Ratios in Copolymerization from a Single Sample and Its Application to the Acrylonitrile–Methyl Methacrylate System

Copolymerization with depropagation. VIII. A general solution for reversible multicomponent polymerization

AbstractA method is described for calculating instantaneous polymer composition for an n‐component system polymerizing under conditions where reversibility of the propagation reaction must be considered. The resulting equations are compared with Monte‐Carlo simulations and were also tested experimentally by using the terpolymerizing system acrylonitrile–methyl methacrylate–α‐methylstyrene over both a wide temperature and concentration range.

Étude de la cotacticité des copolymères acrylonitrile‐méthacrylate de methyle par resonance magnetique nucléaire—haute resolution

AbstractA study of the NMR spectra of acrylonitrile–methyl methacrylate copolymers (PAM) with very low percentages of methyl methacrylate (M) allows quantitative determinations of AMA, and MMA or AMM triad sequences from the methoxy resonances. The resolution of the complex α‐methyl resonances of the isolated M units in seven components has been attempted. If our assignments are correct, the analysis of the cotactic pentad sequences (with a M in central position) has revealed that the configurations of the copolymer chain do not follow the Bernouillian or the first‐order Markoffian statistics.

Acrylonitrile Copolymerizations. III. Flash Pyrolysis of Methyl Methacrylate and Styrene Copolymers

Abstract Flash pyrolysis of the copolymers acrylonitrile-methyl methacrylate and acrylonitrile-styrene has been carried out over the whole range of compositions, and yields of the monomers have been measured. In the first case, all of the methyl methacrylate is recovered as monomer except when a unit is isolated between two acrylonitrile segments. However, the yield in acrylonitrile monomer is lower; it corresponds to the units isolated between long sequences of methyl methacrylate plus the isolated acrylonitrile diads. The agreement between the calculated and experimental yields is excellent only if one takes into account the penultimate effects. In the second case, however, it is not possible to deduce a quantitative interpretation of the yields of either styrene or acrylonitrile monomers.

Acrylonitrile Copolymerizations. I. Penultimate Effects

Abstract Kinetics studies, using the gas-chromatographic method, of the two copolymerizations acrylonitrile-methyl methacrylate and styrene-acrylonitrile, show that remote units effects do operate on the reactivity of each radical species. The corresponding reactivity ratios are:

Solution Properties of the Methyl Methacrylate-Acrylonitrile Copolymer

Abstract Short-range interactions between chain units of random copolymers in solution may be influenced by the characters of the pendant side groupes or, more precisely, by the dipole moment of the substituent. In those experiments the steric factor was derived for a random copolymer composed of methyl methacrylate and acrylonitrile from the relation between the limiting viscosity number and the molecular weight. Mark-Houwink relations were obtained in N,N′-dimethylformamide (DMF) and in methyl ethyl ketone (MEK) at 30°C for the copolymer containing 0.48 mol fraction of acrylonitrile, and for polymethyl methacrylate (PMMA) for the sake of comparison: [η]=4.61×10−4M0.65 for the copolymer in DMF [η]=1.70×10−4M0.65 for PMMA in DMF [η]=1.26×10−3M0.52 for the copolymer in MEK With the Stockmayer-Fixman expression, these correlations become, respectively: [η]=213×10−5M1⁄2+12.4×10−7M [η]=78.2×10−5M1⁄2+5.05×10−7M [η]=163×10−5M1⁄2+1.05×10−7M The unperturbed mean square end-to-end distance, 〈L2〉0, determined from the first term of the latter expressions, together with the 〈L2〉0f value calculated by assuming the completely free rotation, gives the steric factor of σ=(〈L2〉0⁄〈L2〉0f)1⁄2 2.59±0.01 from the DMF solution; this factor is larger than that for polymethyl methacrylate (2.11±0.08),, and that for polyacrylonitrile (2.20+0.05). The steric parameter derived from the MEK solution is 2.37±0.05 for this co-polymer; this value does not agree with the value obtained from the DMF solution. In both cases, it may be concluded that the dimensions of the copolymer between acrylonitrile and methyl methacrylate are influenced by the electrostatic interactions between nitrile groups of acrylonitrile units and methoxy-carbonile and/or methyl groups of methyl methacrylate units. The second virial coefficient in MEK obtained from the light scattering measurements also has a larger value for this copolymer than for polymethyl methacrylate. This tendency of copolymers to show a larger second virial coefficient seems to be an essential characteristic of some copolymers.

Fractionation of acrylonitrile copolymers. I. Development of a method

AbstractThe mechanism of precipitation of acrylonitrile polymers was investigated using different nonsolvents. The effect of the dielectric constant and the polarity of individual bonds in the molecule of precipitant is discussed briefly. A methyl methacrylate–acrylonitrile copolymer was successfully fractionated from dimethylformamide solution, using a two‐stage fractionation technique, and a mixture of (2 parts n‐hexane + 1 part ether) as a precipitant. The molecular weight distributions of primary fractions were skewed to the left and overlapped each other. A large, 100‐g. sample of the same copolymer was separated into eight primary fractions, which on refractionation gave a result substantially the same as that obtained by the small scale experiment. An experimental terpolymer of methylvinylpyridine–vinyl acetate–acrylonitrile, prepared by suspension polymerization, was carefully fractionated by the same method. The polymer was shown to have a double‐peak molecular weight distribution in agreement with the earlier suggestion that acrylonitrile in aqueous suspension polymerizes by two simultaneous mechanisms: (1) homogeneous polymerization of single radicals in solution, and (2) heterogeneous growth of radicals present in stable suspended polymer particles. The above conclusion was further supported by methylvinylpyridine analysis on secondary fractions. It was found that the low molecular weight fractions contained appreciably more of the water‐soluble monomer (M.V.P.), than the high molecular weight fractions.

Copolymerization studies. II. Effect of high pressures on monomer reactivity ratios

AbstractStudies of the effect of pressure on comonomer reactivity ratios in the styrene—acrylonitrile and methyl methacrylate—acrylonitrile systems show that the values of r1 and r2 increase in both cases and that the relative activation volumes (ΔV11‡ − ΔV12‡) are −9.8 and −9.5 cc./mole respectively, where acrylonitrile is monomer 2. The product r1r2 increases toward unity in both systems. A study of the effect of temperature on these reactivity ratios shows that (ΔH11‡ — ΔH12‡) is essentially zero for methyl methacrylate—acrylonitrile, but 500 cal./mole for styrene—acrylonitrile. Within the pressure range studied, it has been found that the e values for the two monomer pairs are dependent upon pressure, tending to become equal, the higher the pressure, while the Q values are relatively unaffected by pressures up to 1000 atm.