Papers by Author: Li Rong Mo

Abstract: In this paper, using sodium phosphate and calcium nitrate as reagents, nano-hydroxyapatite (n-HA) was synthesised under 8 conditions. The morphology and crystallinity of these prepared HA were investigated by Transmission Electron Microscope (TEM) and X-ray diffraction pattern (XRD). The Ca/P molar ratio of n-HA was tested by chemical method. In order to find a better way to obtain purer nano-hydroxyapatite, the phases transition and purification of these 8 samples before and after sintering at 1000°C were compared. The results indicated that all these samples showed similar, poorly crystallized apatite structures before sintering. The adding order between calcium and phosphate would affect the crystallinity, structure and Ca/P molar ratio of hydoxyapatite significantly. XRD analysis showed that adding sodium phosphate into calcium nitrate could gain more HA phase after sintering at 1000°C. The pH of reaction system had obvious effects on the structure of hydroxyapatite. Besides the pH of reactants also affected the structure of hydoxyapatite.

Abstract: The compatibility efficiency on different compatibilizer for nano-hydroxyapatite (n-HA) reinforced polyamide 66 (PA66) and high density polyethylene (HDPE) blends at a composition of 40/42/18 as functionalized biomaterial was investigated by mechanical properties testing and scanning electron microscopy (SEM). The results showed that mechanical properties of compatibilized blends were much improved by the compatibilizers of maleic anhydride grafted polyethylene (PE-g-MAH) and ethylene/methacrylic acid ionomer-sodium ion (ION) compared with the uncompatibilized blends. Blends had peak mechanical values of different compatibilizer. Both PE-g and ION formed adhesion during melt mixing and stabilized the morphology and significantly reduced the size of dispersed PE phase. PE-g gave the blends with PE spheres ranging from 1 to 4µm and ION with well-dispersed spheres with an average diameter of 1µm. The more enlarged interphase of the blends containing ION reduced the lower interfacial energy to increase the miscibiliy of the blends. Consequently, ION had better contribution to rigidity properties than PE-g for n-HA/PA/PE blends.