Effect of strontium oxide (SrO) on the microstructure and bioactivity of melt derived bioactive silicate glass

Department of Chemical Technology, University of Calcutta, 92, Acharya Prafulla Chandra Road,
Kolkata-700 009, India
Department of Ceramic Technology, Government College of Engineering and Ceramic Technology,
73, Abinash Chandra Banerjee Lane, Kolkata-700 010, India
E-mail: kabdkd@yahoo.co.in, ceramic.ramkaran53@gmail.com
Manuscript received 20 February 2018, revised 10 May 2018, accepted 14 May 2018

Bioactive glass 46.1 SiO₂ 24.4 Na₂O (26.9–x) CaO 2.6 P₂O₅.xSrO (x = 0, 2, 4, 6 mol%) have been prepared using the conventional
melting and annealing method. The glass samples were characterized by Density measurement, Powder X-Ray Diffraction
(XRD), Fourier Transformed Infrared (FTIR) spectroscopy and Scanning Electron Microscopy (SEM) with Energy Dispersive
X-Ray Analysis (EDX). Bioactivity of the glass was measured by SEM with EDS, pH measurement and ionic concentrations
analysis after immersion in SBF solution for different days at 37.5ºC.
Experimental results showed that SrO substitution for CaO in the glass increased glass density and molar volume whereas
oxygen density was decreased. The glass transition temperature and crystallization temperature were decreased with increase
in strontium oxide substitution. The XRD and FTIR spectra showed the formation of the crypto crystalline hydroxy apatite (HA)
on the surface of bioactive glass samples after immersing in SBF for 14 days. SEM of the 14 days immersed sample shows
the formation of cotton ball like HCA layer on the glass. EDS analysis also confirmed the formation of HCA layer. Effect of
strontium oxide substitution on the pH, silicon ion concentration and the weight loss after SBF immersion of the different glass
samples are discussed.