壳聚糖改性及其在造纸白水中的抑菌应用研究

Application of Modified Chitosan as Bacteriostatic Agent in White Water

壳聚糖经冰醋酸溶解、氢氧化钠碱性润胀和冷冻预处理后,利用有机溶剂对壳聚糖置换脱水,再与2,3-环氧丙基三甲基氯化铵(ETA)制备不同取代度的壳聚糖季铵盐;利用制备的壳聚糖季铵盐作为抑菌剂对造纸厂白水中常见的细菌(如大肠杆菌和金黄色葡萄球菌等)进行抑菌实验,并与常用抑菌剂进行比较,且将其与常用抑菌剂异噻唑啉酮复配,进行大肠杆菌和金黄色葡萄糖球菌抑菌效果实验。实验结果表明,通过用异丙醇对壳聚糖置换脱水,与空白样相比壳聚糖季铵盐得率提高14.3个百分点,产物得率最高可达到60.3%;从实际抑菌效果及生产成本考虑,最佳底物反应比例是n(壳聚糖)∶n(ETA)=1∶6;壳聚糖季铵盐也是一种广谱抑菌剂,在异噻唑啉酮中加入用量20%的壳聚糖季铵盐,具有最好的复配抑菌性能。

Natural chitosan（ CTS） was first dissolved in acetic acid and fully swelled up with sodium hydroxide,then dehydrated by organic solvents. Subsequently the quatemary ammonium chitosan（ QCS） with different substitution degrees were synthesized by the reaction of chitosan 2,3-epoxypropyl trimethyl ammonium chloride（ ETA） in different ratio. Two strains including Gram negative E. coli and Gram positive S. aureus were selected for antibacterial tests because they are commonly found in papermaking white water. The antibacterial activities of QCS,isothiazolinone and their mixture were also investigated. Result indicated that isopropyl alcohol was better than ethyl alcohol using for dehydration,the yield of dehydrating chitosan with isopropyl alcohol reached to 60. 3%,and 14. 3 percentage points higher than the control sample. From the point of view of actual bacteriostatic effect and the production costs,the best n（ CTS） ∶ n（ ETA） was 1∶ 6. Chitosan quaternary ammonium salt was a broad-spectrum antibacterial agent,the best bacteriostatic performance was achieved by adding 20% quaternary ammonium salt of chitosan to isothiazolinone.