Impact of oxygen transport properties on polypropylene thermal oxidation, part 1: Effect of oxygen solubility

François-Heude, Alexandre; Richaud, Emmanuel; Guinault, Alain; Desnoux, Eric; Colin, Xavier

doi:10.1002/app.41441

Cited by 16 publications

(31 citation statements)

References 111 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In comparison, for a bimolecular decomposition, this value would have been appreciably lower: typically E a = 100-110 kJ mol −1 [22,23].…”

Section: Resultsmentioning

confidence: 96%

“…Indeed, for a moderately oxidizable polymer such as PE, E a is quite high: E a ≈ 138 kJ mol −1 [22]. In contrast, for highly oxidizable polymers such as PP or unsaturated elastomers, E a is significantly lower: E a ≈ 92 kJ mol −1 for PP [23] and E a ≈ 84 kJ mol −1 for HTPB [24]. As feared, the presence of aromatic rings in the vicinity of the CH 3 groups greatly increases the oxidation sensitivity of these latter.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Multi-scale and multi-technical analysis of the thermal degradation of poly(ether imide)

Courvoisier

Bicaba

Colin

2018

Polymer Degradation and Stability

Self Cite

View full text Add to dashboard Cite

is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. A B S T R A C TThe thermal degradation of PEI has been studied in wide ranges of temperature (between 180 and 250°C) and oxygen partial pressure (between 0.21 and 50 bars). On one hand, the chemical ageing mechanisms have been analysed and elucidated by FTIR spectrophotometry and by differential calorimetry (DSC) on sufficiently thin PEI films (between 10 and 60 μm thickness) to be totally free of the effects of oxygen diffusion. As expected, and by analogy with other aromatic polymers of similar chemical structure, oxidation occurs preferentially on the methyl groups of the isopropylidene unit of the bisphenol A part, thus causing the disappearance of their characteristic IR absorption band at 2970 cm −1 and the growth of a new IR absorption band at 3350 cm −1 , attributed to alcohols. In addition, oxidation leads successively to a relative predominance of chain scissions and crosslinking, resulting in a non-monotonic change of T g . On the other hand, the consequences of oxidation on the elastic properties have been analysed and elucidated by micro-indentation on polished cross-sections of PEI plates of 3 mm thickness. The diffusion control of oxidation leads to the development of profiles of Young's modulus within the sample thickness, which correlate perfectly with the changes in chemical structure determined by FTIR spectrophotometry. However, the increase in Young's modulus in the superficial oxidized layer is not the direct consequence of oxidation but of a physical ageing.

show abstract

“…In comparison, for a bimolecular decomposition, this value would have been appreciably lower: typically E a = 100-110 kJ mol −1 [22,23].…”

Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 99%

Multi-scale and multi-technical analysis of the thermal degradation of poly(ether imide)

Courvoisier

Bicaba

Colin

2018

Polymer Degradation and Stability

Self Cite

View full text Add to dashboard Cite

show abstract

“…This value is much lower than the steady concentration of hydroperoxides found for pure thermal oxidation at the same temperature. Indeed, their steady concentration is a decreasing function of temperature [30,47]: in air, it is 0.6, 0.5 and 0.4 mol L À1 at 80, 60 and 45 C respectively. This result suggests that hydroperoxides photolysis would be a source of radicals as important as hydroperoxides thermolysis for all the exposure conditions under study.…”

Section: Comparison With Pure Thermal Oxidationmentioning

confidence: 99%

“…thermo-, radio-and photo-oxidation) differ exclusively by the nature of their initiation step. Thus, the mechanistic scheme of photothermal oxidation can be obtained by introducing, into the now common "closed-loop mechanistic scheme" (CLMS) previously established for pure iPP thermal oxidation [30,31], additional initiation steps due to the effect of UV-light, in particular the photolysis of cleavable photosensitive species (i.e. chromophores).…”

Section: Multi-closed-loop Mechanistic Scheme (Mclms)mentioning

confidence: 99%

See 1 more Smart Citation

A general kinetic model for the photothermal oxidation of polypropylene

François-Heude

Richaud

Desnoux

et al. 2015

Journal of Photochemistry and Photobiology A: Chemistry

View full text Add to dashboard Cite

is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. A B S T R A C TA general kinetic model for the photothermal oxidation of polypropylene has been derived from the basic auto-oxidation mechanistic scheme in which the main sources of radicals are the thermolysis and photolysis of the most unstable species, i.e hydroperoxides. Thermolysis is a uni-or bi-molecular reaction whose rate constant obeys an Arrhenius law. In contrast, photolysis is exclusively a unimolecular reaction and its rate constant is independent of temperature. According to the quantum theory, this latter is proportional to the energy absorbed by photosensitive species and thus, accounts for the impact of UVlight intensity and wavelength on the global oxidation kinetics.The validity of this model has been checked on iPP films homogeneously oxidized in air over a wide range of temperatures and UV-light sources. It gives access to the concentration changes of: (i) primary (hydroperoxides) and secondary (carbonyls) oxidation products, (ii) double bonds, (iii) chain scissions and crosslinking nodes, but also to the subsequent changes in molecular masses. These calculations are in full agreement with the photolysis results reported by Carlsson and Wiles in the 70s [1][2][3]. However, the model seems to be only valid for UV-light energies equivalent to about 10 suns as upper boundary, presumably because of multiphotonic excitations or chromophores photosensitization (i.e. termolecular photo-physical reactions), both enhanced at high irradiances.

show abstract

Impact of oxygen transport properties on the kinetic modeling of polypropylene thermal oxidation. II. Effect of oxygen diffusivity

François-Heude

Richaud

Guinault

et al. 2014

J of Applied Polymer Sci

Self Cite

View full text Add to dashboard Cite

The kinetic model, established in a previous article (Franc¸ois-Heude et al., J. Appl. Polym. Sci., in press) to predict the homogeneous oxidation in iPP films typically thinner than 100 mm, is now extended to simulate the oxidation profiles in thicker plates by coupling the oxygen diffusion and its consumption by the chemical reactions. In this perspective, oxygen transport properties (namely oxygen solubility, diffusivity, and permeability) are measured by permeametry on a reference iPP. These values are compared with an exhaustive compilation of literature data to evaluate their variability among the whole iPP family, which one has been reasonably ascribed to initial differences in polymer morphology, but also to evaluate their consistency, especially their temperature dependence between 20 and 140 C. Failing to simulate oxidation profiles, the kinetic model is then used as an inverse resolution method for estimating more satisfactory values of oxygen transport properties. It is thus evidenced that the crystallinity changes induced by thermal oxidation largely explains the dramatic decrease in oxygen penetration toward the sample core just after the induction period. A strategy aimed for introducing the relationship between the polymer crystalline morphology and oxygen transport properties into the kinetic model is given in the graphical abstract, although the effect of polymer polarity remains to be established prior to this implementation.

show abstract

Impact of oxygen transport properties on polypropylene thermal oxidation, part 1: Effect of oxygen solubility

Cited by 16 publications

References 111 publications

Multi-scale and multi-technical analysis of the thermal degradation of poly(ether imide)

Multi-scale and multi-technical analysis of the thermal degradation of poly(ether imide)

A general kinetic model for the photothermal oxidation of polypropylene

Impact of oxygen transport properties on the kinetic modeling of polypropylene thermal oxidation. II. Effect of oxygen diffusivity

Contact Info

Product

Resources

About