Effect of volatilization of stabilizers and oxidation products on polypropylene lifetimes

Blumberg, M; Boss, C.; Chien, James C. W.

doi:10.1002/app.1965.070091204

Cited by 25 publications

(8 citation statements)

References 7 publications

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“…This group is expected to be unaffected by chemical changes occurring during stabilization events but it can, indeed, disappear by physical loss of stabilizer. 26 The results [ Fig. 6(a,b) the global trend being given by dashed lines] show clearly that for durations of the order of the induction period, the physical loss can be considered as negligible in the timescale under study, that is not very surprising considering the very low diffusivity and volatile loss of the Irganox 1010 molecule.…”

Section: Resultsmentioning

confidence: 85%

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Accelerated ageing of polypropylene stabilized by phenolic antioxidants under high oxygen pressure

Richaud

Farcas

Fayolle

et al. 2008

J of Applied Polymer Sci

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Polypropylene (PP) samples stabilized by a hindered phenol (Irganox 1010) were submitted to thermal ageing at 80 C in air at atmospheric pressure or in pure oxygen at 5.0 MPa pressure. Both the polymer oxidation and the stabilizer consumption were monitored by Infrared spectrometry and thermal analysis. The stabilizer efficiency, as assessed by the ratio induction time/stabilizer concentration is almost constant at atmospheric pressure even when the stabilizer concentration is higher than its solubility limit in PP (0.4% or 24 Â 10 À3 mol L À1). In contrast, at high pressure, the efficiency decreases almost hyperbolically with the stabilizer concentration when this latter is higher than 6.0 Â 10 À3 mol L À1 . The results indicate the existence of a direct phenol-oxygen reaction negligible at low oxygen pressure but significant at 5.0 MPa pressure. The reality of this reaction has been proved on the basis of a study of the thermal oxidation of a phenol solution in a nonoxidizable solvent. A kinetic model of PP oxidation in which stabilization involves three reactions has been proposed. It simulates correctly the effect of oxygen pressure and stabilizer concentration on carbonyl build-up and stabilizer consumption.

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Section: Resultsmentioning

confidence: 85%

“…To check an eventual effect of stabilizer loss by evaporation/diffusion, we have monitored the absorbance of the ester group at 1745 cm −1 during thermal ageing. This group is expected to be unaffected by chemical changes occurring during stabilization events but it can, indeed, disappear by physical loss of stabilizer 26…”

Section: Resultsmentioning

confidence: 99%

Accelerated ageing of polypropylene stabilized by phenolic antioxidants under high oxygen pressure

Richaud

Farcas

Fayolle

et al. 2008

J of Applied Polymer Sci

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“…Styrene polymerization could result from either reaction (15) or (16). In accelerated aging tests at 130°C, the metal dithiolenes are prooxidants for polypropylene and epichlorohydrin-ethylene oxide copolymer (Tables V and VI).…”

Section: Effectiveness Of Hydroperoxide Decomposer As Synergistic Antmentioning

confidence: 99%

Sulfur compounds as synergistic antioxidants

Chien

Boss

1972

J. Polym. Sci. A‐1 Polym. Chem.

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synopsisThe decomposition of tertbutyl, cumyl, and polypropylene hydroperoxides catalyzed by SO2, H301, dilauryl thiodipropionate, metal dithiolenes, and metal dithiocarbamates were studied. The principal reaction pathways leading to difierent products, which depend on the nature of the hydroperoxide and the sulfur compounds, were discussed. Even though metal dithiolenes are remarkable hydroperoxide decomposers, they are prooxidants for polymers under accelerated aging conditions. This is attributed to the instability of the peroxy radical-metal dithiolene complex intermediates. Expressions for optimum composition for each component of a synergistic antioxidant system have been derived. 1579

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“…That all the oxygen absorbed during this time is quantitatively converted to hydroperoxide has been firmly established for the autoxidation of polypropylene in our laboratories. Others (15,16) have shown that this is also true for the autoxidation of polyethylene.…”

Section: Kinetics Of Autoxidation Of Polypropylene (4)mentioning

confidence: 77%