One pot blending of biopolymer‐TiO2 composite membranes with enhanced mechanical strength

A biopolymer‐TiO₂ composite membrane was prepared by blending of N‐[(2‐hydroxy‐3‐trimethylammonium) propyl] chloride chitosan and cellulose acetate with nano‐TiO₂ particles as the introduced inorganic components. It was verified that the amino groups (? NH₂) of chitosan (CTS) were partly grafted by stronger hydrophilic group ? according to the ¹H‐nuclear magnetic resonance spectra of N‐[(2‐hydroxy‐3‐trimethylammonium) propyl] chloride chitosan and attenuated total reflectance Fourier transform infrared spectroscopy. The structure, microcosmic morphology, water flux, swelling properties, and thermal stability of the composite membranes were characterized. With the mass ratio of cellulose acetate to CTS being 50 wt %, the mole ratio of CTS to glycidyl trimethylammonium chloride being 1 : 1, and drying temperature being 60°C in 70% acetic acid, the formed biopolymer‐TiO₂ composite membranes exhibited enhanced mechanical strength (84.29 MPa), lower swelling degree (101.36%), and improved antibacterial activity against Gram‐negative Escherichia coli (Rosetta and DH5α) and Gram‐positive Bacillus subtilis. The existence of nano‐TiO₂ particles and the introduction of stronger cationic group synergistically improved the antibacterial properties of the biopolymer‐TiO₂ composite membranes. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42732.