Preparation and characterization of new quaternized carboxymethyl chitosan/rectorite nanocomposite

Quaternized carboxymethyl chitosan (QCMC) was intercalated into the interlayer of rectorite (REC) to prepare QCMC/REC nanocomposite. XRD and TEM results revealed that REC was well dispersed in the polymer matrix and obtained the largest interlayer distance when the mass ratio of QCMC to REC was 2:1. FTIR, NMR and zeta-potential analyses showed that the intercalation of QCMC did not destroy the structure of REC layer, but there were hydrogen-bonding and electrostatic interactions between QCMC and REC. Quaternized chitosan (HTCC)/REC nanocomposite was prepared and studied in parallel. The comparative analysis of the two biopolymer/clay nanocomposites indicated that the free volume and positive charge density of biopolymers were important factors that affected the intercalation of biopolymer into clay. At last, thermal analysis indicated that QCMC/REC nanocomposites had obviously higher thermal stability in comparison with QCMC. This study shows that the combination with clay materials is a functional way to expand the possible application of QCMC as drug controlled-release carriers, antimicrobial agent and pulp-cap.