Synthesis of porous metakaolin geopolymer as bone substitute materials

Metakaolin-based porous geopolymer had been successfully developed using aluminum powder by creating bubbles in the structure. These structures were required to mimic the spongy bone thus may be applied as bone substitute materials. It was conducted by adding the aluminum powder in the mixture of Metakaolin (MK) and Alkaline Activator (AA) (NaOH solution and sodium silicate) with ratio 1:1, 1:1,5, 1: 2, 1:2,5 and 1:3 then namely sample A-E respectively. The slurry was then poured into mold 30 x 30 x 30 mm³. Samples were let harden and heated in the oven 80ºC for 4 hours prior to demolding. Scanning Electron Microscope (SEM) and X-ray diffraction (XRD) were used to observe the morphology of porosity resulted in the samples and to characterize the crystallinity of the samples. The results showed porous metakaolin geopolymer of sample A had the most similarity with the human spongy bone (80-400 µm). Along with an increase in the amount of AA, crystallinity of albite show a decrease of intensity. This study concluded the porous metakaolin geopolymer obtained was potential to be used as a bone substitutes materials.