Polystyrene thermodegradation. III. Effect of acidic catalysts on radical formation and volatile product distribution

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Abstract

The catalytic degradation of polystyrene, carried out in sealed tubes with different acidic catalysts (i.e., silica, zeolites, and silica-aluminas), was studied. Two reaction temperatures, 350 and 400°C, for reaction times up to 120 min were investigated. The reaction was followed both by electron spin resonance and gas chromatography-mass spectrometric analysis. The different distributions of volatile products (C6–C24) obtained in the various cases are discussed, arranging the products into groups. An initiation mechanism, involving the formation of radical cations, is proposed for the degradation of polystyrene on strongly acidic catalysts.

References (20)

  • AudisioG. et al.

    J. Anal. Appl. Pyrolysis

    (1984)
  • BeltrameP.L. et al.

    Polym. Degrad. Stab.

    (1989)
  • AudisioG. et al.

    Polym. Degrad. Stab.

    (1990)
  • GuyotA.

    Polym. Degr. Stab.

    (1986)
  • UemichiY. et al.

    J. Chromatorg.

    (1983)
  • IshiharaY. et al.

    Fuel

    (1990)
  • NaccacheC.M. et al.

    J. Catal.

    (1971)
  • KaminskyW.
  • AudisioG. et al.
  • MaderF.W.
There are more references available in the full text version of this article.

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    Citation Excerpt :

    Some unusual selectivity vs x profiles for Tol are discussed further below.) The observed steady increase with increasing x at 350 °C [37a,e] and approximately constant concentration of abstractable back-bone hydrogens do not follow if the key competition involved is transfer vs β-scission of DPP as in the usual models, i.e., kH[M]/kβ ≈ constant, but could suggest an increasing diversion of Tol from Tol to another product, specifically D. For a one-point comparison at x ≈ 0.06 where Broadbelt and coworkers [37a,e] reported <0.1 at 350 °C (large head-space), Schroder and coworkers [21b] reported 2.3 at 336 °C (closed system but small head-space); the disparity is striking. Relying more on the former data, we dare only set a target of <1 for DPP:Tol at 350 °C.

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