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Interference between reactants in simultaneous interpenetrating polymer network formation. II. Influence of the presence of a free-radical initiator on polyurethane formation

Authors

  • Mohamed Tahar Tabka,

    1. Institut Préparatoire aux Etudes d'Ingénieur de Nabeul, Université du 7 Novembre de Carthage, Campus Universitaire Merazka, 8000 Nabeul, Tunisia
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  • Jean-Michel Widmaier

    Corresponding author
    1. Institut Charles Sadron (CNRS-ULP), UPR 0022, 6, rue Boussingault, 67083 Strasbourg Cedex, France
    • Institut Charles Sadron (CNRS-ULP), UPR 0022, 6, rue Boussingault, 67083 Strasbourg Cedex, France
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Abstract

Polyether polyurethane networks were prepared in solution at 25 and 60°C, using various organotin catalysts. The presence of a free-radical initiator [viz. azobisisobutyronitrile (AIBN)] in the reaction media has no effect on the catalytic efficiency of organotin(IV) compounds, whereas it causes severe deactivation of organotin(II) compounds. This effect was explained by the following mechanism: formation of a cyclic 1 : 1 complex by coordination of the nitrile groups of AIBN with the tin(II) atom, which both reduces the effective catalyst concentration and allows the early decomposition into radicals, as previously seen, leading to tin oxidation. The addition of a free-radical scavenger such as 3-tert-butyl pyrocatechol allows the maintenance of the catalyst efficiency of organotin(II) compounds at their reference level. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1929–1937, 2002

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