Effect of Sericin in [HA/Bioplastic] Composite Composed by 2k Factorial Design Method on Solidification Time and Tensile Strength

摘要

Synthetic hydroxyapatite has been attractive ceramic for a decade as main material of bonegraft. However, in powder form it was difficult to shape into certain geometry due to its brittleness characteristic. For this, composing it with another biomaterial as a matrix in a proper composition can be a challenging. In the present work, bioplastic (B) made of cassava starch was selected as a matrix material and silk sericin (SS) extracted from B.mori cocoon was added. Hydroxyapatite was obtained from bovine hydroxyapatite (H). The composite was prepared by mixing of H/B with ratio of 20/80 and 80/20 and sericin of 8% and 16%w/w was blended to form pasta. It was then casted layer by layer (0.1mm and 0.5mm thick) into mould with size of 6mm diameter and 3mm deep. The composite component was composed by utilizing 2k Factorial Design Method and selected the highest of diametral tensile strength (DTS). ANOVA was performed to evaluate hypothesis H0 and H1 based upon the sources and two regression models of Y=f(X,?) that represented solidification time and tensile strength were developed. The result of solidification time model reveals that composite [H80/B20/S16] with 0.1mm layer thickness had the shortest time of 106.36sec and the highest DTS of 3.46MPa. These results were slightly lower than that obtained by experiment i.e. 107sec and 3.88MPa, respectively. Additional sericin twice for this composite gains more significant effect in improving DTS and solidification time compared to that of giving hydroxyapatite.