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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
Author(s) -
Tabka Mohamed Tahar,
Widmaier JeanMichel
Publication year - 2002
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.10755
Subject(s) - azobisisobutyronitrile , polyurethane , chemistry , catalysis , radical , radical initiator , tin , polymer chemistry , decomposition , nitrile , reaction mechanism , polymer , copolymer , organic chemistry
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