The kinetics of thermo-oxidative degradation of oriented polypropylene in relation to the structure and molecular mobility of the polymer

Rapoport, Natalya; Berulava, S.I.; Kovarskii, A. L.; Musayelyan, I.N.; Yershov, Yu.A.; Miller, V.B.

doi:10.1016/0032-3950(75)90430-x

Cited by 28 publications

(13 citation statements)

References 8 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%

“…Similarly, the variability of the oxygen solubility enables to simulate a larger cluster of maximal oxidation rates among the compilation of literature data than the effect of the crystallinity ratio alone (see Figure ). Moreover, the highest value of solubility, more consistent with the compilation of iPP data than the previous one, does not allow to simulate the upper range of this compilation, particularly above 110°C.…”

Section: Discussion: Towards a “Universal” Kinetic Modelmentioning

confidence: 99%

“…The introduction of variability on the oxygen solubility can be connected with the effect of morphology on the polymer sensitivity to oxidation. Indeed, the induction period was reported to decrease with increasing density and crystallinity ratio, crystallites size or annealing temperature as reviewed by Vink . These results, somewhat conflicting in a first approach, could be the consequence of the existence of different iPP crystalline structures.…”

Section: Discussion: Towards a “Universal” Kinetic Modelmentioning

confidence: 99%

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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%

Section: Discussion: Towards a “Universal” Kinetic Modelmentioning

confidence: 99%

Section: Discussion: Towards a “Universal” Kinetic Modelmentioning

confidence: 99%

See 1 more Smart Citation

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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“…This result could be understood as the increase in the intensity of the β-relaxation being attributed to the shift of the crystalline relaxation to the lower temperature while the damping capacity of the amorphous relaxation may actually decrease, which also reflects the reduction in the segmental mobility of the amorphous phase. As the oxidation reactions mainly take place in the amorphous regions, it is likely that a reduction in the molecular mobility would lower the rate of abstraction of hydrogen from the polymer chain, and thus lower the rates of reactions of initiation, propagation and chain branching [47], which in fact lead to a higher oxidative stability.…”

Section: Mechanisms For the Improved Thermal Oxidation Stabilitymentioning

confidence: 99%

Improved thermal oxidation stability of polypropylene films in the presence of β-nucleating agent

Huang

Kong

et al. 2013

Polymer Testing

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“…Preliminary experiments showed that clay can be dispersed by melt processing in the presence of air as well as by annealing in the presence of air.The interaction of pristine PP and of PP/OLS with oxygen has been studied by several investigators. [6][7][8][9][10][11][12] These studies were concerned mainly with the degradation of the polymer by thermal oxidation. The extent of oxidation was monitored by determining the carbonyl groups spectroscopically by ATR-FTIR.…”

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confidence: 99%

Oxidation−Migration Cycle in Polypropylene-Based Nanocomposites

Lewin¹,

Tang²

2007

Macromolecules

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Polypropylene (PP) appears to be the most widely investigated polymer for use in the preparation and application of nanocomposites. PP as a highly hydrophobic and nonpolar polymer can be used for the preparation of nanococmposites only after a compatibilzing process in which polar groups are introduced. 1 Among the modifications described in the current literature, the most prevalent consists of grafting maleic anhydride (MA) onto PP. However, this treatment is connected with a number of complications including such side reactions as -scission, chain transfer, coupling, and, above all, severe decrease of the molecular weight. 2-5 One of the aims of this study is to explore the possibility of dispersing organo-layered silicates (OLS) in pristine PP in the presence of air, without pretreatment. Preliminary experiments showed that clay can be dispersed by melt processing in the presence of air as well as by annealing in the presence of air.The interaction of pristine PP and of PP/OLS with oxygen has been studied by several investigators. 6-12 These studies were concerned mainly with the degradation of the polymer by thermal oxidation. The extent of oxidation was monitored by determining the carbonyl groups spectroscopically by ATR-FTIR. The above studies were not concerned with investigating the effect of oxidation on the structure of PP-based nanocomposites. 13,14 A preliminary study on the effect of air oxidation of poly(ethylene-co-vinyl acetate) (EVA) was reported in the literature, and whereas changes in the nanocomposite structure were noticed, they do not pertain to PP nanocomposites due to the differences in chemical structure between the two matrix polymers. 15 A preliminary study of the effect of oxygen on the structure of PP/OLS was recently carried out in these laboratories. 16 It was shown that whereas the structure of PolyOne PP does not change upon annealing with N 2 , profound changes occur in the PP/OLS structure upon annealing under a stream of air. These changes were monitored by XRD and by migration of clay to the surface as determined by ATR-FTIR. 16,17 Additional results on the effect of oxygen during annealing of maleic anhydride (MA) grafted PP were also recently obtained. 18 In this study a limited concentration of air, up to 25% of the purging gas, was used, and effects of two structure modifiers were studied simultaneously, one of the grafted MA and the other of the oxygen. In the present study the effects of increasing concentrations of air up to 100% of the purging gas were studied on pristine PP without any other compatibilizers.The experiments described in the present communication were carried out at 180 and 190°C. These temperatures are below the onset temperature of the decomposition of the surfactant in the clay. This was confirmed by dynamic and isothermal TGA measurements, carried out in these laboratories, and not reported here, which showed a very small weight loss in the temperature range when the TGA was carried out at an atmosphere of N 2 as well as N 2 containing 12.5% air....

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The kinetics of thermo-oxidative degradation of oriented polypropylene in relation to the structure and molecular mobility of the polymer

Cited by 28 publications

References 8 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

Improved thermal oxidation stability of polypropylene films in the presence of β-nucleating agent

Oxidation−Migration Cycle in Polypropylene-Based Nanocomposites

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