The deterioration of polypropylene by oxidative degradation

Oswald, H. J.; Turi, E. A.

doi:10.1002/pen.760050312

Cited by 79 publications

(20 citation statements)

References 5 publications

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“…The variation of S O2 now enables to simulate the whole range of induction times compiled from the literature under 0.1 MPa and 0.02 MPa, except the lowest values attributed to polypropylenes which are atactic, preoxidized or with a high catalyst residues amount (Figure ). The slope of the Arrhenius graph, i.e.…”

Section: Discussion: Towards a “Universal” Kinetic Modelmentioning

confidence: 99%

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

François-Heude

Richaud

Guinault

et al. 2014

J of Applied Polymer Sci

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A general kinetic model is proposed to describe the polypropylene thermal oxidation of thin polypropylene films in a wide range of temperatures (from 60 to 200 C) and oxygen partial pressures (from 0.02 to 5 MPa) using a single set of parameters.This model was calibrated with several series of experimental data including analyses of primary (hydroperoxides) and secondary oxidation products (carbonyl species), and subsequent changes in macromolecular properties (average molecular masses). It predicts the experimental data previously published in the literature in terms of induction times and maximal oxidation rates. The variability of the oxygen solubility coefficient allows to explain the scattering of induction times and oxidation rates among the whole iPP family, but also the dependence of this latter quantity with oxygen partial pressure. This variability is presumably due to iPP polymorphism in the temperature range where oxygen permeability is commonly measured. It is concluded that the kinetic model can be used to study the direct effect of iPP morphology on its thermal oxidation kinetics (chemistry of oxidation).

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Section: Discussion: Towards a “Universal” Kinetic Modelmentioning

confidence: 99%

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

François-Heude

Richaud

Guinault

et al. 2014

J of Applied Polymer Sci

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“…Normally polymers are applied below their processing temperature, it has been shown that at these temperatures in an environment without oxygen polymers hardly degrade [1,2,3]. The reduction of the properties in an air environment is a result of reactions with oxygen.…”

Section: Influence Of Oxygenmentioning

confidence: 99%

“…Another decomposition reaction of hydroperoxides with lower activation energy is the decomposition catalyzed by transition metal ions [40,41] Termination reactions are bimolecular (stage 4). In the presence of sufficient air, which normally is the case during long-term degradation of polymers, only the reaction of two peroxy radicals has to be considered [1]. The reaction depends on the type of peroxy radical present.…”

Section: Influence Of Oxygenmentioning

confidence: 99%

Review on the thermo-oxidative degradation of polymers during processing and in service

Gijsman

2008

E-Polymers

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“…It is known that the core of crystallites is inert to oxidation, but their surfaces and boundary regions could well be oxidized (e.g., scission of the tie-chains between the crystallites). 17 On the basis of the results, it is suggested that the decrease in melting peak temperature is due to less-ordered crystallites in aged material (i.e., an oxidation-induced increase in surface energy of the crystallites). Figure 4 presents profiles through thickness of the relative carbonyl ratio as a function of distance from surface for heat-stabilized samples (S2).…”

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confidence: 96%

Effect of thermal-oxidative aging on mechanical, chemical, and thermal properties of recycled polyamide 66

Eriksson

Boydell²,

Eriksson³

et al. 1997

J. Appl. Polym. Sci.

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This article addresses the effect of thermal aging on unreinforced and glassreinforced recycled polyamide 66. As an accelerated test, injection-molded test bars were aged at 110, 140, and 170ЊC for up to 4000 h in air to simulate service life. FTIR spectroscopy demonstrated that the oxidative degradation primarily occurred between the surface and a depth of 0.5 mm. Furthermore, the degradation in the surface region was more pronounced with recycled as well as unstabilized materials. Reprocessing resulted in a faster increase of carbonyl groups, a decrease in melting peak temperature, and elongation at break during subsequent aging. Because of process-induced fiber shortening, however, the elongation at break of recycled reinforced samples was always at least as high as that of virgin samples for up to 4000 h of aging at 140ЊC. The decrease in melting peak temperature as determined by differential scanning calorimetry (DSC) indicated that the surface or boundary regions of the crystallites in the material are affected by aging. The loss in elongation at break for the reinforced material was shown to correlate with the reduction in melting peak temperature of material taken from the surface region of aged samples. The contribution of the degraded surface region to the properties was studied by removal of surface layers prior to testing. The degradation in the surface region was the sole cause, even of glass fiber-reinforced polyamide, for the embrittlement of aged samples. Furthermore, aging-induced changes in tensile strength and modulus were independent of the removal of the surface region, indicating that these properties are controlled by changes occurring in the bulk of the material.

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The deterioration of polypropylene by oxidative degradation

Abstract: 90--0 a 120oc "6 loo--L 80--70--14OOC 0 0" m 60--

Cited by 79 publications

References 5 publications

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

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

Review on the thermo-oxidative degradation of polymers during processing and in service

Effect of thermal-oxidative aging on mechanical, chemical, and thermal properties of recycled polyamide 66

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