Papers by Author: A. Zuraida

Abstract: Porous tri-calcium phosphate which is to be applied as artificial bone was prepared via protein consolidation method and egg yolk is used to give binding effect as well as to create porosity. In this experiment, fractions of egg yolk is controlled from 50 wt%, 60 wt%, 70wt% and 80 wt% and the mixture of egg yolk and tri-calcium phosphate powder were dried at 60 °C before undergone uniaxial compaction method. Subsequently, pressure of 68.5 MPa is given to the mold to produce cylindrical shape samples with diameter to height ratio of 1:2. Samples were then sintered at 1100°C to achieve porous tri-calcium phosphate. This method produces porous tri-calcium phosphate with desired porosity of 20-54.5% and acceptable compressive strength between 0.7-0.07 MPa. Besides, microporosity of 0.4-1μm and macroporosity in the range of 100-800μm were successfully obtained from this method.

Abstract: Porous tri-calcium phosphate, well-known for its use as artificial bone, was prepared via sponge polymeric method by the application of low cost polyurethane (PU) foam as a structural guide. In this experiment, fractions of tri-calcium phosphate (TCP) are controlled at 12, 13, 14, 15 and 16 grams and mixed with distilled water (fixed at 25 grams) to produce slurries. Subsequently, rectangular shaped PU foam was immersed in the slurry and dried for three days. Samples were then sintered at 1100°C to obtain porous tri-calcium phosphate. This method produces porous tri-calcium phosphate with porosity between 31-44% and the compressive strength in the range of 0.17-1.02 MPa. The macroporosity of the tri-calcium phosphate, observed through SEM, was in the range of 100 µm to 900 µm.

Abstract: The attention in natural fiber reinforced biopolymer composite materials has been rapidly growing both in terms of industrial applications and basic research. This study was addressed to the investigation of the impact properties and fracture behaviour of biodegradable composites made from egg albumen reinforced by natural cotton fibres. The albumen-cotton composites have been fabricated by hands lay-up technique at varied volume fiber fraction from 2, 4, 6, 8, and 10 vol.% cotton. The specimens were cured at room temperature for a fixed time of 14 days to ensure the specimens are fully dried and harden, before being subjected to mechanical test. The cotton fibres have contributed in a significant improvement in fracture toughness of the composites. The obtained impact strength varied from 15.0 to 19.0 kJ/m2, and the fracture toughness varied from 0.7177 to 0.9453 J depending on vol.% cotton, with the optimum mechanical performance was obtained at 6 vol.% cotton. Morphological observation using SEM revealed that most of the fabricated specimens failed due to fiber breakage, pull out, and void growth.

Abstract: Manganese is one of metallic elements which appear in biological apatite like bone and teeth. Its important effect on the growth and development of bone has been well known. Here, we have synthesized manganese-doped hydroxyapatite (HA) via sol-gel method. White ammoniacal solution of monomers were refluxed until white gel formed, followed by drying and calcination at 500 – 900°C. Four different concentration of manganese (2, 5, 10 and 15 mol%) were successfully incorporated into HA crystals. XRD analysis showed that the crystallinity increased with the increased amount of manganese. SEM measurement also showed that individual particles become bigger with the increasing content of Mn. Tricalcium phosphate appeared as an additional phase when calcined at 800°C. It was also proven that the incorporation of manganese reduced the peak intensity of tricalcium phosphate. FTIR analysis is in good agreement with the results from XRD measurement where the peaks of OH (630 cm-1) and PO4 3- (565 cm-1, 601 cm-1, 960 cm-1, 1020 cm-1 and 1100 cm-1) bands of HA phase show higher intensity with the increasing concentration of manganese. FTIR measurement also showed that the presence of HPO4 2- (880cm-1) decreased in intensity with the increased Mn content, showing that the anion exist in less crystalline phase of HA.