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With the development of the technology of ring-opening polymerization (ROP) rapidly, many novel aluminum complexes have been designed, synthesized, and applied in initiating ROP of cyclic esters and new stereoregular polymerization mechanism of lactide polymerization have been reported. In this review, the mechanism for ROP of cyclic ester, synthesis of aluminum complexes containing tetradendete ligand, tridentate ligand, bidentate ligand, and bimetallic complexes containing aluminum were reviewed. We hope to give some helpful information for designing aluminum complexes, improving activity, and stereoregularity of aluminum complexes.

Poly(lactide-co-glycolide)/bone meals composites using poly(lactide-co-glycolide) (PLGA) and bone meals (BM) as the starting materials were successfully prepared via solution dispersion method. Fourier Transform Infrared (FTIR) spectroscopy, X-ray diffraction and BET were used to characterize the resulting PLGA and bone meals. The mechanical properties of composites were carried out by the three-point-bending test, and the micrographs of cross-section of composites were observed using SEM. The results indicate that both the bending strength and modulus of PLGA/BM composites increased with bone meals increasing up to 10 wt%, then decreased with bone meals content, indicating that the fracture feature of PLGA/BM composites changed from typical brittle to ductile fracture when the bone meals content changed from 0 to 10 wt% and from ductile to brittle facture while bone meals content ranging from 10 to 20 wt%. It was further confirmed by SEM images of composites. The biocompatibility results show that result...

HA/PLGA composites with and without APS-modification were successfully prepared via solution dispersion method. The mechanical test of composites was performed by the three-point-bending test and the micrographs of materials were observed using SEM. The results indicate that by surface modification, uniform HA particles without agglomeration were obtained. Furthermore, the bending strengths and moduli of APS-HA/PLGA composites are higher than those of unmodified composites, which both first increased and then significantly decreased with increasing the HA content. The biocompatibility results show that modified HA/PLGA composite are more favorable biomaterials for cell adhesion, differentiation and proliferation than unmodified composites.

Porous sol-gel glass of CaO-SiO2-P2O5 system with macropores larger than 100 μm was prepared by adding stearic acid as pore former when the sintering was carried out at 700 °C for 3 h. The sol-gel porous glass shows an amorphous structure. The diameter of the pore created by pore former varies from 100 to 300 μm, and macroporous glass has a narrow and small pore size distribution in mesoporous scale. The porosity and pore size of macroporous bioactive glass can be controlled.

Poly-L-lactide(PLLA) was synthesized by ring-opening polymerization from high purity L-lactide with tin octoate as initiator, and characterized by means of infrared, and 1H-nuclear magnetic resonance. The influences of initiator concentration, polymerization temperature and polymerization time on the viscosity average molecular mass of PLLA were investigated. The effects of different purification methods on the concentration of initiator and viscosity average molecular mass were also studied. PLLA with a viscosity average molecular mass of about 50.5×104 was obtained when polymerization was conducted for 24 h at 140 °C with the molar ratio of monomer to purification initator being 12 000. After purification, the concentration of tin octoate decreases; however, the effect of different purification methods on the viscosity average molecular mass of PLLA is different, and the obtained PLLA is a typical amorphous polymeric material. The crystallinity of PLLA decreases with the increase of viscosity average molecular mass.