INVESTIGADORES
DELL'ERBA ignacio Esteban
artículos
Título:
Photopolymerization of methacrylate monomers using polyhedral silsesquioxanes bearing side-chain amines as photoinitiator
Autor/es:
S. V. ASMUSSEN; I. E. DELL'ERBA; W. F. SCHROEDER; C. I. VALLO
Revista:
EUROPEAN POLYMER JOURNAL
Editorial:
PERGAMON-ELSEVIER SCIENCE LTD
Referencias:
Lugar: Amsterdam; Año: 2011 p. 309 - 317
ISSN:
0014-3057
Resumen:
Organotriethoxysilanes (APS-PGE2) were synthesized by reacting 1mol of 3-(aminopropyl)
triethoxysilane with 2 mol of 1,2-epoxy-3-phenoxypropane (PGE). Polyhedral oligomeric
silsesquioxanes functionalized with bulky amino groups (ASSQO) were prepared by hydrolytic
condensation of APS-PGE2 catalyzed by formic acid. Methacrylate resins were activated
for visible light polymerization by the addition of 1 wt.% CQ in combination with the synthesized
ASSQO at loadings between 0 and 30 wt.%. The progress of monomer conversion versus
irradiation time showed that the CQ/ASSQOpair is an efficient photoinitiator system because
a fast reaction and high conversion result from 60 s irradiation at 600 mW/cm2. The lack of
methacrylate groups in the ASSQO, able to polymerize with the methacrylate resin, results
in the absence of chemical bond between the ASSQO cages and the matrix. Debonding of ASSQO
cages from the polymer give rise to nanovoids; which allows the methacrylate matrix to
yield and deform plastically. Consequently, the final effect is a decrease in the flexural modulus
and compressive strength with increasing amounts of ASSQO. The present study highlights
the surface effect on the overall properties in nanostructured materials.