Inhomogeneous thermo-oxidative degradation during heat ageing of aliphatic polyamides in bulk

Vasil'ev, V.A.; Kudryavtseva, G. A.; Pavlov, N. N.

doi:10.1016/0032-3950(86)90056-0

Cited by 2 publications

(1 citation statement)

References 2 publications

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“…In our previous paper on polyamide 11 thermal oxidation [5], we showed that chain scissions induced by oxidation radical chain reactions remained predominant over crosslinking for temperatures ranging from 90 to 165°C and oxygen pressure ranging from 0.02 MPa (ambient atmosphere) to 2.0 MPa, which is also observed during polyamide radio-oxidation [6]. Since polyamide end groups remain reactive in the solid state, some condensation reaction namely solid state polymerization (SSP) is expected to occur as observed for example in the bulk of PA6 thick pieces [7,8].…”

Section: Introductionmentioning

confidence: 75%

Molecular and macromolecular structure changes in polyamide 11 during thermal oxidation – Kinetic modeling

Okamba-Diogo

Richaud

Verdú

et al. 2015

Polymer Degradation and Stability

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The oxidation kinetics of unstabilized polyamide 11 thin film under oxygen pressures up to 2.0 MPa was studied by means of ferrous ion method for hydroperoxides titration, size exclusion chromatography (SEC) for molar weight measurements and in situ FTIR monitoring for carbonyl build up. Oxidation was shown not to be limited by oxygen diffusion which militates in favor of the use of a simple kinetic model for simulating experimental data. The kinetic parameters of this model were estimated from literature for initiation and propagation, and from selective experiments such as ageing under several oxygen pressures for the estimation of the termination rate constants, or exposures under inert atmosphere to investigate the solid state polymerization effects and tentatively check the boundary conditions of the model. The kinetic model simulates satisfyingly the overall experimental results using the minimal number of adjustable parameters (except for some reactions difficult to be experimentally isolated and studied).

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Section: Introductionmentioning

confidence: 75%

Molecular and macromolecular structure changes in polyamide 11 during thermal oxidation – Kinetic modeling

Okamba-Diogo

Richaud

Verdú

et al. 2015

Polymer Degradation and Stability

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Elevated temperature nanoindentation behaviour of polyamide 6

Seltzer

Kim

Mai

2011

Polymer International

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It has been found, in this study, that there is no close correlation between the tensile and nanoindentation moduli of polyamide 6 (PA6) at high temperatures. It is demonstrated that heat modifies the surface of PA6 specimens, but its effect on the nanomechanical properties is minor. The main spurious factor which affects the nanoindentation results is adhesion, especially at low indentation depths. The overestimation in the measured indentation moduli can be corrected by performing indentations with loads high enough so that the modulus is independent of the applied load. It is concluded that the lack of strict correlations between the tensile and indentation moduli (after corrections of adhesion) is caused by the shift in the glass transition temperature of PA6 owing to the hydrostatic stress imposed by the indenter. Further proof is given with two examples on hydrostatic pressure‐dependent polymers: polytetrafluoroethylene and polycarbonate. Copyright © 2011 Society of Chemical Industry

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Inhomogeneous thermo-oxidative degradation during heat ageing of aliphatic polyamides in bulk

Cited by 2 publications

References 2 publications

Molecular and macromolecular structure changes in polyamide 11 during thermal oxidation – Kinetic modeling

Molecular and macromolecular structure changes in polyamide 11 during thermal oxidation – Kinetic modeling

Elevated temperature nanoindentation behaviour of polyamide 6

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