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Condensation of alkoxysilanes in alcoholic media: I. Oligomerization of dimethyldiethoxysilane
Author(s) -
BennevaultCelton Véronique,
Maciejak Olek,
Desmazières Bernard,
Cheradame Hervé
Publication year - 2010
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/pi.2687
Subject(s) - condensation polymer , condensation , monomer , context (archaeology) , anhydrous , methanol , condensation reaction , ethanol , chemistry , reaction rate constant , hydrolysis , kinetics , polymer chemistry , organic chemistry , chemical engineering , polymer , thermodynamics , catalysis , physics , paleontology , quantum mechanics , biology , engineering
In the context of the preservation of cultural heritage, the treatment of paper by an aminoalkylalkoxysilane, or its mixture with dimethyldiethoxysilane, has given encouraging results. Diluting the monomer bearing the amino function could contribute to obtaining a flexible network interpenetrating the fibre network. Due to the complexity of the system, the work presented here begins with a study of dimethyldiethoxysilane condensation under the conditions used for the paper deacidification (alcoholic medium, neutral condition, etc.). No detectable exchange reaction with ethanol was observed in anhydrous systems of dimethyldiethoxysilane for 24 h, but in the presence of water, hydrolysis and exchange were observed, the rate constant of the former being higher than that of the latter by one order of magnitude. In methanol, in the presence of water, condensation leading to dimerization was observed within less than three days, with polycondensation requiring a much longer time. From the rate constant measurements, in the presence of water, it appears that the condensation reaction is the slowest reaction. It can be concluded that with freshly prepared dimethyldiethoxysilane solutions in ethanol, this monomer cannot homopolymerize. The next step will be to determine to what extent it can be integrated into the network formed by the polycondensation of aminoalkylalkoxysilane. Copyright © 2009 Society of Chemical Industry