Odd-even effect and thermal stability in the series of vinyl polymers

Shibaev, L. A.; Stepanov, N. G.; Zuev, V. V.; Solovskaya, N. A.; Sazanov, Yu. N.

doi:10.1016/0040-6031(91)87019-s

Cited by 11 publications

(8 citation statements)

References 5 publications

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“…The arrangement of atoms in the chain depends on the degree of freedom for each carbon–carbon bond in terms of torsion angle between the atoms or groups. Similar odd‐even trend is observed in tensile properties and moisture absorption in polymers such as polyamides and vinyl polymers …”

Section: Resultssupporting

confidence: 72%

Poly(alkyl lactate acrylate)s having tunable hydrophilicity

Purushothaman

Krishnan

Nayak

2014

J of Applied Polymer Sci

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Four alkyl lactates and alkyl lactate acrylates having methyl, ethyl, propyl, and butyl as alkyl moiety were synthesized by azeotropic distillation. Their formation was confirmed by Fourier transform infrared (FTIR), mass, 1H nuclear magnetic resonance (NMR) and proton decoupled 13C NMR spectroscopic techniques. Solution polymerization was carried out for these alkyl lactate acrylates and the formed homopolymers were characterized by FTIR, 1H NMR, proton decoupled 13C NMR spectroscopic, and gel permeation chromatographic techniques. Shear thinning behavior was observed for all the polymers. Wide angle X‐ray Diffraction studies showed that the polymers were amorphous in nature and also exhibited odd‐even effect among alkyl lactate groups with respect to average molecular interchain spacing. Depending on the length of the alkyl lactate groups, relative humidity and time, the hydrophilicity of the polymers decreased with increase in the length of the alkyl lactate group among the odd and even series. Among the studied polymers, poly(ethyl lactate acrylate) may have the potential for hydrogel applications, due to its highly hydrophilic nature. Tg decreased with increase in length of alkyl lactate groups. Trend observed on the thermal stabilities of poly(alkyl lactate acrylate)s could be explained on the basis of average molecular interchain spacing. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40962.

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Section: Resultssupporting

confidence: 72%

Poly(alkyl lactate acrylate)s having tunable hydrophilicity

Purushothaman

Krishnan

Nayak

2014

J of Applied Polymer Sci

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“…The longer the alkyl group, the higher will be the delocalization of the charge at the carbon atom linking two monomer units, and thus it is more stable. When the alkyl group is small, the delocalization of the electrons will be less, so the tendency to form radicals is more . The 13 C NMR spectra of PMA (Figure a), PEA (Figure b), and PBA (Figure c) support this hypothesis.…”

Section: Resultsmentioning

confidence: 83%

“…The degradation rate coefficients (×10 -7 mol g -1 min -1 ), k 1 , are 4.08, 3.40, and 2.95 for PMA, PEA, and PBA, respectively. The decrease in the rate coefficient with an increase in the alkyl group chain length can be explained in terms of the delocalization of electrons . The longer the alkyl group, the higher will be the delocalization of the charge at the carbon atom linking two monomer units, and thus it is more stable.…”

Section: Resultsmentioning

confidence: 99%

Effect of Alkyl Group Substituents, Temperature, and Solvents on the Ultrasonic Degradation of Poly(n-alkyl acrylates)

Mahalik

Madras

2005

Ind. Eng. Chem. Res.

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The effect of alkyl group substituents on the degradation kinetics of poly(alkyl methacrylates) namely poly (n-butyl methacrylate) (PBMA), poly (iso-propyl methacrylate) (PPMA), poly (ethyl methacrylate) (PEMA), and poly (methyl methacrylate) (PMMA) in supercritical and subcritical conditions was studied at various temperatures (250-375 o C). The molecular weight distributions were measured by gel permeation chromatography and continuous distribution kinetic models were used to determine the degradation rate coefficients. The degradation rate coefficients in the supercritical condition were found to be significantly higher than that in the subcritical condition. The degradation rate of poly(alkyl methacrylates) increased with increase in the number of carbon atom of the alkyl substituents and thus followed the order PBMA>PPMA>PEMA>PMMA. The activation energy decreased with chain length in both subcritical and supercritical conditions. The degradation of PBMA was investigated at various pressures (20 − 85 bar) at 325 0 C and the effect of pressure on the degradation rate coefficient was modeled using transition state theory. The degradation of PBMA was also investigated in different solvents at 325 0 C and 60 bar. The supercritical state and the density of the solvent were found to be important factors that influences the degradation kinetics.

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“…The variation of activation energy with chain length (Figure 6) is the same for degradation by pyrolysis and in solution. The above trend can be explained in terms of the delocalization of electrons 33 . The longer the alkyl group, higher is the delocalization at the carbon atom linking two monomer units and thus more stable.…”

Section: Thermal Degradation In Solutionmentioning

confidence: 92%

Effect of the Alkyl Group Substituents on the Thermal and Enzymatic Degradation of Poly(n-alkyl acrylates)

Mahalik

Madras

2005

Ind. Eng. Chem. Res.

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The effect of alkyl group substituents on the thermal degradation kinetics of poly (n-alkyl acrylate) was investigated in pyrolysis and in solution. The activation energies for the pyrolytic degradation of poly (n-butyl acrylate) (PBA), poly (ethyl acrylate) (PEA), and poly (methyl acrylate) (PMA), determined by the Friedman's technique, were 150, 170 and 203 kJ/mol, respectively. For the thermal degradation of the polymers in solution, a continuous distribution kinetic model was used to determine the random chain degradation rate coefficients. The activation energies, determined from the temperature dependence of the rate coefficients, for PBA, PEA and PMA in solution were 109, 117, and 138 kJ/mol, respectively. This indicates that the variation of the activation energies with chain length of the substituent in the polymer is similar to degradation both by pyrolysis and in solution, though the values obtained are lower for degradation in solution. The enzymatic degradation of these polymers was also investigated at different temperatures with various enzymes (Novozym 435, Lipolase and Porcine Pancreas) in different solvents. A continuous distribution kinetic model was used to evaluate the polymer chain end scission rate coefficient. The degradation rates were highest when the acrylates were degraded in presence of Porcine Pancreas in toluene at 50 0 C.

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Odd-even effect and thermal stability in the series of vinyl polymers

Cited by 11 publications

References 5 publications

Poly(alkyl lactate acrylate)s having tunable hydrophilicity

Poly(alkyl lactate acrylate)s having tunable hydrophilicity

Effect of Alkyl Group Substituents, Temperature, and Solvents on the Ultrasonic Degradation of Poly(n-alkyl acrylates)

Effect of the Alkyl Group Substituents on the Thermal and Enzymatic Degradation of Poly(n-alkyl acrylates)

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