Surface modification of nanocrystalline hydroxyapatite

Nanometre-scale hydroxyapatite (nano-HA) is the key component to manufacture biomaterial. In this work, the surface of nano-HA particle was modified by KH-550 silane coupling agent and the coupling mechanism was investigated. The results showed that the coupling treatment on the surface of nano-HA particle did not change its micromorphology and microstructure. The hydrolysis reaction of KH-550 is a multistage dissociation of the chemical equilibrium process and produces lots of Si-OH group. With the hydrolysis time prolonged, polycondensation reaction of parts of Si-OH group occurs and produces Si-O-Si groups. Furthermore, coupling mechanisms of KH-550 with nano-HA is mainly predominated by three mechanisms such as chemical bond theory, hydrogen bond theory and double electronic shell theory.