Water-soluble N-(2-hydroxyl) propyl-3-trimethyl ammonium chitosan chloride (HTCC) was prepared with 2, 3-epoxypropyl trimethyl ammonium chloride grafting to the amino groups of chitosan. Then, chitosan quaternary ammonium intercalated saponite (HTCC-saponite) was synthesized with HTCC and saponite by ultrasonication intercalation. Compared with chitosan, HTCC had a good antibacterial effect. Thermoplastic poly(lactic acid) (PLA)/HTCC-saponite nanocomposites were prepared with HTCC-saponite and PLA by melt intercalation. Fourier transform infrared (FTIR) and nuclear magnetic resonance (1H NMR) showed that HTCC was successfully synthesized by a modified method of two-step reaction. Moreover, X-ray diffraction (XRD) and scanning electron microscope (SEM) also showed that saponite was intercalated or nearly exfoliated by HTCC. It was shown the mechanical properties of PLA/HTCC-saponite nanocomposites attained the optimum when the content of HTCC-saponite was 1 phr. The studies of thermal stability, crystallization and rheological behavior of PLA/HTCC-saponite nanocomposites demonstrated that PLA/HTCC-saponite nanocomposites exhibited high performance compared with PLA.

Keywords: chitosan quaternary ammonium; melt intercalation; poly(lactic acid); saponite; nanocomposites