Suitability of rice hull ash as substitute to reagent SiO2 in the synthesis of Apatite/Wollastonite (A

Date

5-2008

Degree

Bachelor of Science in Applied Physics

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Emmanuel A Florido

Abstract

The suitability of rice hull ash as source of silica (SiO2) in the synthesis of bioactive apatite/wollastonite (A/W) glass-ceramics with formulations of 4.6% MgO, 44.7% CaO, 34.0% Si02, 16.2% P205, and 0.5% CaF2 was investigated. Apatite/Wollastonite (A/W) glass-ceramics are bioactive glass-ceramics that have the capacity to bond to bone and hence can be used as a bone implant. A formulation (E, experimental) using rice hull ash as substitute for Si02 was compared with a formulation (C, control) using reagent grade Si02. The two formulations were melted in an electric furnace at 1300°C for 1 hour and 30 minutes. fitted in water, dried, powdered in a vibrating mill for 1 hour and pressed into pellets of 24mm diameter x 3mm height at 5 tons pressure. The formulations were then heat treated at 600°C for 1 hour and 30 minutes nucleation time and at 1000°C for 30 minutes crystallization time. In vitro bioactivity test was done by soaking the samples in SBF for 3 and 5 days and incubating them at 37°C. XRF spectrometry identified calcium as the major peak present on the spectra of both rice hut ash-substituted A/W glass-ceramic and analytical A/W glass-ceramic. SEM showed the formation of HCA layer on the control samples but not on the experimental samples. FTIR spectrum of C samples implied that SBF-material interaction occurred, resulting to the formation of HCA layer; whereas, FT1R spectrum of E samples did not yield significant results regarding HCA layer formation. The unsuitability of rice hull ash as substitute for Si02 in the synthesis of bioactive apatite/wollastonite (A/W) glass-ceramics may be attributed to impurities present in the ash. The nature and effects of these impurities need further investigation.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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