The study of tri-phasic interactions in nano-hydroxyapatite/konjac glucomannan/chitosan composite

The interactions among the three phases of nano-hydroxyapatite (n-HA), Konjac glucomannan (KGM) and Chitosan (CS) in n-HA/KGM/CS composite were investigated using TEM, IR, XRD, XPS and TGA methods. The crystalline structure of n-HA was studied by means of Rietveld method. A series of structure parameters, such as, cell lattice parameters (a or c), bonding lengths and a numerical index of distortion for PO4 tetrahedron, were calculated by Newton–Raphson calculating method to characterize the crystalline structure of HA at atom level. The results showed that n-HA was mainly linked with KGM and CS by hydrogen bonding between OH−–PO 4 3− of n-HA and –C=O, –NH of KGM-CS copolymer, and there was a stable interface formed between the three phases in the composite. Besides, orientation of this hydrogen bonding resulted in the decrease of the relative crystallization degree of KGM-CS copolymer.