Sinthesys of Silsesquioxanes Based in [3-(Methacryloxy)propyl]trimethoxysilane Using Methacrylate Monomers as Reactive Solvents

SILVANA ASMUSSEN; SILVANA L. GIUDICCESI,; CLAUDIA VALLO; ERRA BALSELLS, ROSA

EUROPEAN POLYMER JOURNAL

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2010 vol. 46 p. 1815 - 1823

0014-3057

Abstract: ABSTRACT: The polycondensation of (3-methacryloxypropyl)-trimethoxysilane in acid conditions using different methacrylate monomer as reactive solvents results in incompletely condensed methacrylate-functionalized silsesquioxanes with a very large fraction of intramolecular cycles. UV-MALDI-TOF MS analysis demonstrated that the species present after 2 weeks of reaction at 60 °C were: T6 (OH)2, T7(OH), T8(OH)2, T9 (OH), T10(OH)2 and T11(OH). Analysis of samples after 30 months of storage at room temperature revealed the presence of T12(OH)2 and T13(OH) species. The absence of higher molar mass oligomers after prolonged storage periods is attributed to the fact that dilution of the reacting medium with polar solvents discourages bimolecular reactions that lead to polymer growth. 29Si NMR spectroscopy showed that the conversion in the polycondensation reaction was in the range 0.91-0.96. The methacrylate monomers are not involved in the hydrolysiscondensation reactions with MPTMS and therefore can be polymerized by thermal or photochemical means, thereby cross-linking the preformed nanosized cagelike silsesquioxanes