resumo
Hybrid materials of the polydimethylsiloxane (PDMS)-Tetraethyl orthosilicate (TEOS) system have already been widely described by several authors, being their potential for biological applications largely studied. For some bone related applications, the addition of Ca to these systems is commonly accepted as necessary for the enhancement of bioactivity. However Ca is commonly introduced in the form of calcium nitrate, which requires a heat treatment step in order to eliminate the nitrate residues. The aim of the present work is to produce a PDMS-SiO2-CaO-TiO2 hybrid material through a sol-gel process, for potential biomedical applications. Calcium nitrate was used as the calcium source and to avoid the presence of nitrate residues in the final product, a heat-treating step at 400 degrees C was performed. Titanium was added to the hybrid system in order to enhance the thermal stability of the materials subjected to this temperature. TGA, FT-IR and Si-29 NMR techniques were used to understand the role of the calcium and titanium in the structure formation, and the way they influence the thermal stability of the PDMS -SiO2 system. A final material containing calcium, with no traces of nitrate and the maintenance of a significant amount of methyl groups was successfully obtained. (C) 2013 Elsevier B.V. All rights reserved.
palavras-chave
ORGANICALLY MODIFIED SILICATE; NUCLEAR-MAGNETIC-RESONANCE; SILOXANE-OXIDE MATERIALS; STATE SI-29 NMR; FT-IR; ORMOSILS; TEOS; NANOCOMPOSITES; DEGRADATION; TEMPERATURE
categoria
Materials Science
autores
Almeida, JC; Castro, AGB; Lancastre, JJH; Salvado, IMM; Margaca, FMA; Fernandes, MHV; Ferreira, LM; Casimiro, MH
nossos autores
Isabel Margarida Miranda Salvado
Professor associado
José Carlos Martins de Almeida
Investigador Júnior
Maria Helena Figueira Vaz Fernandes
Professor(a) Jubilado(a)Grupos
G3 - Materiais Eletroquímicos, Interfaces e Revestimentos
G5 - Materiais Biomiméticos, Biológicos e Vivos
agradecimentos
This work is financed by FEDER funds, through the Program COMPETE, and by FCT (Fundacao para a Ciencia e Tecnologia) funds, on the project PTDC/CTM/101115/2008 and by the grant SFRH/BD/72074/2010 and SFRH/BPD/26961/2006. We also want to acknowledge the program which is financing CICECO and REQIMTE at present, Pest-C/CTM/LA0011/2011 and Pest-C/EQB/LA0006/2013 respectively.