Microbiocidal activity of chitosan‐N‐2‐hydroxypropyl trimethyl ammonium chloride

Chitosan‐N‐2‐hydroxypropyl trimethyl ammonium chloride (QTS) was prepared by reaction of chitosan with glycidyl trimethylammonium chloride, which was characterized by FTIR. QTS with different molecular weights (Mw 41.55 × 104, 9.02 × 104, 3.57 × 104, and 0.17 × 104) showed biocidal activity on Staphylococcua aureus, Bacillus subtilis, Staphylococcua epidermidis, and Candida albicans. QTS with high molecular weight had high biocidal activity on the gram‐positive bacteria, and the biocidal effect of QTS decreased with decreasing molecular weight from 9.02 × 104 to 0.17 × 104. QTS with Mw 41.55 × 104 exhibits slightly lower biocidal activity on Candida albicans than other QTS samples. However, no remarkable biocidal activity of QTS was found on gram‐negative bacteria Escherichia coli and Pseudomonas aeruginosa at the concentration up to 10 g L−1. Existence of cationic surfactant, amphoteric surfactant, nonionic surfactant, Ca2+ and Mg2+ had no remarkable effect on microbiocidal activity of these QTS samples.