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.