resumo
This work investigates the effects of the type and concentration of acid catalysts on the microstructural features of silica-rich bioactive glasses (75Si-16Ca-5Na-4P, in mol%) synthesized from acetate and nitrate precursor salts, using an innovative rapid sol-gel method, followed by thermal stabilization at 550 degrees C. The results of XRD, SEM, Fourier Transform Infrared Spectrometer (FTIR) and solid state MAS NMR analysis revealed that the lower degrees of polymerization and network connectivity were found for bioglass powders obtained in the presence of high acid concentrations. A low amount of citric acid gave a polymerization degree similar to that obtained in the absence of any catalyst, but the synthesis time was as short as that found for high acid concentrations. The XRD and FTIR results demonstrated amorphous glass powders free of any nitrate by-products. The microstructure and degree of polymerization could be modified by changing the type and concentration of acid catalyst, enabling one to tailor the bioactivity of glasses even without changing the starting composition.
palavras-chave
BIOACTIVE GLASSES; INFRARED-SPECTROSCOPY; NITRATE HYDRATE; HYDROLYSIS; TETRAETHOXYSILANE; SPECTRA; CALCIUM; SILICA; SYSTEM; CONDENSATION
categoria
Materials Science
autores
Ben-Arfa, BAE; Fernandes, HR; Salvado, IMM; Ferreira, JMF; Pullar, RC
nossos autores
Basam Abobaker Emhmed Ben-Arfa
Investigador
Hugo Alexandre Gonçalves da Rocha Fernandes
Investigador Júnior
Isabel Margarida Miranda Salvado
Professor associado
José Maria da Fonte Ferreira
Professor(a) Jubilado(a)
Rob Pullar
ColaboradorGrupos
G3 - Materiais Eletroquímicos, Interfaces e Revestimentos
G4 - Materiais Renováveis e Economia Circular
G5 - Materiais Biomiméticos, Biológicos e Vivos
Projectos
agradecimentos
FCT, Grant/Award Number: IF/00681/2015, PTDC/EPH-PAT/6281/2014, UID/CTM/50011/2013