Preparation and Characterization of SiO2 CaO MgO K2O Glasses as Biomaterials

Abstract

Glass and glass-ceramics are very important class of materials. These materials have wide range of applications in nonlinear optical devices, sealants, bioactive materials etc. Bioactivity basically refers to the bone binding capacity of the materials characterized by in-vitro formation of interfacial layer of hydroxyapatite (HAp) or carbonated hydroxyl apatite (HCA) when soaked in stimulated body fluids (SBF). Bioactivity is directly dependent on structural linkage of elements with each other in multi-component system. Glasses convert to glass-ceramics on controlled heat-treatment due to growth of some crystalline phases within the glassy matrix. The volume fraction of the crystalline phase(s) should be limited when better bioactivity along with reasonable mechanical strength and chemical durability is sought. The crystallization kinetics of the glasses using different mathematical models also gives insight of the structure of the glasses. Present thesis describes the preparation of glasses in the system SiO2-K2O-CaO-MgO with variable amount of MgO/CaO. As-quenched glasses have been characterized for their physical, thermal, structural and optical properties. The as-prepared and heat-treated glasses/glass-ceramics were soaked in SBF to check their in-vitro bioactivity. The prominent surface modification/formation could be better observed in pellets than powder form and it also leads to better mechanical compliance. The surface modifications of the samples can also be checked by UV-Visible spectroscopy due to change in absorption of light. However, this technique only gives some qualitative results in terms of disorder induced during surface reactions. Local change in the structure can most suitably be seen by FTIR spectroscopy. The soaked samples have been characterized using various techniques with respect to (w.r.t.) to the unsoaked samples to observe any the formation of HCA layer. The thesis is divided into five chapters with a list of cited references at the end of each chapter.