resumo
In the present paper we describe the surface modification of alumina nanoparticles using epoxy-containing alkoxysilanes (silane coupling agents, SCA). The materials were characterized using infrared spectroscopy and solid-state nuclear magnetic resonance. Whereas, neat alumina nanoparticles could be expectedly modified with the afore mentioned SCA, as evidenced by C-13 CPMAS NMR, the presence of arylsulphonates at the surface of alumina caused the ring-opening polymerization of the epoxide. This polymerization reaction facilitated the surface modification of alumina by the SCA. X-ray powder diffraction and Al-27 MAS NMR clearly demonstrated that in spite of the SCA polymerization, there were neither structural changes nor phase transitions in the alumina after the surface modification. The surface modification decreased the thermal stability of alumina, in comparison to pristine alumina nanoparticles.
palavras-chave
MECHANICAL-PROPERTIES; GAMMA-ALUMINA; ORGANOMETALLIC CHEMISTRY; PERMEABILITY EVALUATION; INORGANIC OXIDES; BOND STRENGTH; RESIN CEMENT; EPOXY-RESINS; COMPOSITES; MEMBRANES
categoria
Chemistry
autores
Prado, LASA; Sriyai, M; Ghislandi, M; Barros-Timmons, A; Schulte, K
nossos autores
Ana Margarida Madeira Viegas de Barros Timmons
Professor associadoagradecimentos
The authors thank the European Union and the Erasmus Munds Program for the financial support given to the present work. Prof. Joao Rocha and the NMR facility of University of Aveiro (Aveiro, Portugal) are acknowledged for the solid-state NMR spectra. The authors thank Prof. Gerald Schneider and the staff of the Institute of Advanced Ceramics Materials at TUHH (Hamburg, Germany) for the XRD measurements.