Preparation and characterization of konjac glucomannan/poly(diallydimethylammonium chloride) antibacterial blend films

A novel antibacterial film was prepared by blending konjac glucomannan (KGM) and poly(diallydimethylammonium chloride) (PDADMAC) in an aqueous system. The antibacterial activity of the films against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, and Saccharomyces were measured by the halo zone test and the double plate method. The films exhibited an excellent antibacterial activity against B. subtilis and S. aureus but not against E. coli, P. aeruginosa or Saccharomyces. The miscibility, morphology, thermal stability, water vapour permeability and mechanical properties of the blend films were investigated by density determination, SEM, ATR-IR, XRD, DSC, TGA, WVA and tensile tests. The results of density determination predicted that the blends of KGM and PDADMAC were miscible when the PDADMAC content was less than 70 wt%. Moreover, SEM and XRD confirmed the result. ATR-IR showed that strong intermolecular hydrogen bonds and electrostatic interactions occurred between KGM and PDADMAC in the blends. The tensile strength and the break elongation of the blends were improved largely to 106.5 MPa and 32.04% and the water vapour permeability decreased when the PDADMAC content was 20 wt%. The thermal stability of the blends was higher than pure KGM. The blends should be good antibacterial materials.