Chelate pyrophosphate titanate coupling agent(NDZ-311)is used as modified agent to modify chitosan(CS).Porous HA-TCP/CS biomaterials are prepared by vacuum freeze drying method.Influence of the amount of coupling agent NDZ-311 on the relationship between compressive strength and porosity of the porous biomaterials is investigated.Analyses of the composite materials are carried out by means of SEM,XRD and IR.The results show that the-O-catenarian aether bond function group in NDZ-311 can induce many types of ester-based transformation reactions to make NDZ-311 and CS filler crosslinking,therefore,the compressive strength of porous biomaterials can be improved by adding NDZ-311 to CS.The addition of CS filler can be more than 50% and can not be separated from phase.Compressive strength of the porous biomaterials decreases with the increase of the content of NDZ-311,and then increases with further increase of the content of NDZ-311.Porosity of the porous biomaterials increases with the increase of the content of NDZ-311,and then decreases with further increase of the content of NDZ-311.Matching of compressive strength and porosity of the porous biomaterials is the best with the mass ratio of HA-TCP to CS 7∶3,the content of NDZ-311 is 1wt% when compressive strength and porosity of the porous biomaterials are 2.3MPa and 84.8%,respectively.Pore shape is stacking fault lath lapping and distribution of pore was comparative uniform.HA-TCP particles are uniformly dispersed on CS templates.The added coupling agent of NDZ-311 has little change on the phase structure of the materials,only the intensity of characteristic diffraction peaks in each phase of the materials has a little enhancement.

Silane coupling agent (KH-570) was used as modifying agent to modify apatite (HA-TCP). Porous HA-TCP/CS biomaterial was prepared by vacuum freeze-drying method. Analyses of the composite were carried out by means of XRD, SEM, TEM, IR and so on. Influence of the amount of coupling agent KH-570 on the relationship between compressive strength and porosity of the porous biomaterial was investigated. The results showed, compressive strength of the porous biomaterial decreased with the increasing of the content of silane coupling agent, and then increased with further increasing of the content of silane coupling agent. Porosity of the porous biomaterial increased with the increasing of the content of silane coupling agent, and then decreased with further increasing of the content of silane coupling agent. Matching of compressive strength and porosity of the porous biomaterial was the best when the mass ratio of HA-TCP to CS is 7:3, and the content of coupling agent KH-570 was 1wt% when compressive strength and porosity of the porous biomaterial were 4.1MPa and 83.8% respectively. The pore shape was stacking fault lath lapping and the distribution of pores is comparatively uniform. HA-TCP particles are uniformly dispersed on CS templates. The added coupling agent of KH-570 has little change on the phase structure of the material, only the intensity of characteristic diffraction peaks in each phase of the material have a little enhancement. The joining mechanism of silane coupling agent is that the -OH in structure could produce firm bonding action with the -OH in the surface of HA-TCP after the decomposition of KH-570. The double bond on the other side of the coupling agent could make the modificative HA-TCP powder more active in the combination with CS. The combination could bridge apatite and CS.