Analysis of the nonvolatile oxidation products of polypropylene I. Thermal oxidation

Adams, Jörg

doi:10.1002/pol.1970.150080505

Cited by 198 publications

(90 citation statements)

References 20 publications

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“…in agreement with the distribution of carbonyl products determined in the literature in photothermal oxidation [30,[50][51][52][53], in particular from the results of Carlsson and Wiles [1][2][3]. First of all, g 1 was increased up to 0.6, since it was reported that more than half the alkoxy radicals undergo b scission [1,2].…”

supporting

confidence: 77%

A general kinetic model for the photothermal oxidation of polypropylene

François-Heude

Richaud

Desnoux

et al. 2015

Journal of Photochemistry and Photobiology A: Chemistry

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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.

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supporting

confidence: 77%

A general kinetic model for the photothermal oxidation of polypropylene

François-Heude

Richaud

Desnoux

et al. 2015

Journal of Photochemistry and Photobiology A: Chemistry

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“…The rate constants of formation of water, acetone, and acetaldehyde are nearly the same in oxygen (200,400, and 600 torr) and in h e l i~m .~ However, it can be assumed that formation of some other minor products of PP oxidation, e.g., 2-methyl-2-propen-1-01 and l-hydroxy-2-propanone, most likely depends on the presence of oxygen during decomposition of PP hydroperoxide, reactions (23) and (24) and (29) and (30). For instance, decomposition of PP hydroperoxide in an inert atmosphere results in particular in the formation of isobutylene,2O reaction (23), whereas in air 2-methyl-2-propen-1-01 has also been found.…”

Section: Imentioning

confidence: 99%

Thermal oxidation of polypropylene close to industrial processing conditions

Hoff

Jacobsson

1982

J of Applied Polymer Sci

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SynopsisThermal oxidation of isotactic polypropylene (PP) at 220 and 280°C in air was studied. Gas chromatography-mass spectrometric analysis was used to separate and identify the volatile products of PP oxidation. Twenty-three products were identified and 15 substances were quantified. The aldehydes are the principal products formed, followed by ketones, acids, and alcohols. The main organic product quantified was acetaldehyde. The volatile organic products formed constitute about 3% of the amount of water formed. The relative amounts of the most volatile products formed in the range 220-280°C are practically independent on the temperature of oxidation. The mechanism of formation on the oxidation products is discussed.

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“…Charring of a polymer under oxygen is a complex process that involves oxidation, the formation of double bonds, cyclization and aromatization [40,41]. PP decomposes via the formation and release of CO, CO2, aldehydes, ketones, carboxylic acids, esters, alkenes, conjugated alkenes and furans [42][43][44]. The FTIR spectra of the volatile decomposition products of PP at maximum release rate are presented in Figure 2.…”

Section: Pyrolysismentioning

confidence: 99%

Flame-Retardancy Properties of Intumescent Ammonium Poly(Phosphate) and Mineral Filler Magnesium Hydroxide in Combination with Graphene

et al. 2014

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Thermally reduced graphite oxide (TRGO), containing only four single carbon layers on average, was combined with ammonium polyphosphate (APP) and magnesium hydroxide (MH), respectively, in polypropylene (PP). The nanoparticle's influence on different flame-retarding systems and possible synergisms in pyrolysis, reaction to small flame, fire behavior and mechanical properties were determined. TRGO has a positive effect on the yield stress, which is decreased by both flame-retardants and acts as a synergist with regard to Young's modulus. The applicability and effects of TRGO as an adjuvant in combination with conventional flame-retardants depends strongly on the particular flame-retardancy mechanism. In the intumescent system, even small concentrations of TRGO change the viscosity of the pyrolysing melt crucially. In case of oxygen index (OI) and UL 94 test, the addition of increasing amounts of TRGO to PP/APP had a negative impact on the oxygen index and the UL 94 classification. Nevertheless, systems with only low amounts (≤1 wt%) of TRGO achieved V-0 classification in the UL 94 test and high oxygen indices (>31 vol%). TRGO strengthens the residue structure of MH and therefore functions as a strong synergist in terms of OI and UL 94 classification (from HB to V-0).

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Analysis of the nonvolatile oxidation products of polypropylene I. Thermal oxidation

Cited by 198 publications

References 20 publications

A general kinetic model for the photothermal oxidation of polypropylene

A general kinetic model for the photothermal oxidation of polypropylene

Thermal oxidation of polypropylene close to industrial processing conditions

Flame-Retardancy Properties of Intumescent Ammonium Poly(Phosphate) and Mineral Filler Magnesium Hydroxide in Combination with Graphene

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