Papers by Author: Yuan Hua Mu

Abstract: Nano-hydroxyapatite/polyamide66/chitosan composite (n-HA/PA66/CS) was prepared by a co-precipitation method and porous scaffolds from n-HA/PA66/CS composite were prepared by means of porogen–leaching method and were characterized by SEM, IR, XRD and universal mechanical testing machine. IR and XRD analyses showed that some chemical bonds existed between n-HA and polymers. Furthermore, macroporous structure of the scaffolds and mechanical strength were tested with a changed ratio of porogens (PVP/NaCl). When the ratio of PVP and NaCl is1: 6, the scaffold processed highly porosity and the pores were interconnected. The compressive strength of the scaffold, can meet the requirement of tissue regeneration.

Abstract: Nano-hydroxyapatite/polyamide66/chitosan composite (n-HA/PA66/CS) was prepared by a co-precipitation method, and was characterized by TG/DTG, TEM, IR, XRD and Universal mechanical testing machine. TEM test showed that some rod like crystals were formed and distributed uniformly into polymer matrix, with a size of about Φ30nm×80nm. IR and XRD analysis showed that some chemical bonds and electrostatic interaction existed between n-HA and polymers. TG/DTG curves indicated that the composites possessed a talent of high heat-resistance. The compressive strength of composite changed with different content of three compounds, the maximum compressive strength of composite (70MPa) could be acquired.

Abstract: The crystallization behavior of n-HA/PA66 biocomposites at different processing pressure and annealing temperature were investigated by XRD and DSC. The results showed that increasing annealing temperature would weaken the crystalline intensities of pure PA66 and its composites. For n-HA/PA66 composites, the peaks of α1 crystals of PA66 disappeared, only α2 crystals existed, and with the increase of injection pressure and annealing temperature, the crystalline intensity of PA66 decreased. The degree of crystallinity (Xc) of PA66 in composites increased with the increase of injection pressure, however, annealing temperature had no obvious effects on crystalline degree. The mechanical properties had close relationship with the crystallization behavior of the materials.

Abstract: Porous n-HA/PVA hydrogel composite was prepared through in-situ hydrothermal treatment under normal pressure and emulsion foam freeze-drying method, which was used to fabricate porous hydrogel. The pores exhibited interconnection-pore structure owing to the injection of air bubbles and the removal of emulsifier (OP). The porous hydrogels were investigated by using IR, XRD, TEM and SEM. The results indicated that n-HA in the composite could disperse uniformly, and there were chemical bonding with PVA. In addition, nano-hydroxyapatite existed in the composite in the shape of short-rod. The pores were interconnection with narrowly pore size and highly porosity. And the pore size and size distribution were influenced by the weight of OP. The emulsion foam freeze-drying method can be used to prepare porous hydrogel scaffold for tissue engineering, or to contain proteins scaffold, because of operating at a low temperature. The method displayed a vast potential of applied foreground.

Abstract: To compare with the human cortical bone, the biomimetic properties of nano-hydroxyapatite/polyamide 66 composite (n-HA/PA66) were preliminarily studied qualitatively and quantitatively with TEM, XRD in crystal morphology, phase composition and crystal structure. A series of structure parameters such as cell lattice parameters (a and c), mean crystallite size and micro-strain were calculated to characterize quantitatively the microstructure of n-HA/PA66 and human cortical bone at the atomic level. The results show that n-HA/PA66 is a good biomimetic biomaterial. But there still are some differences between n-HA/PA66 and human cortical bone. Compared to human cortical bone, the crystal microstructure of n-HA/PA66 is denser, the crystal lattice of n-HA is more perfect and the distortion of crystal lattice decreases.