对羟基苯甲醛表面改性LLDPE/CS共混膜的制备

Preparation of LLDPE /CS Blend Films Surface Modified with P-hydroxybenzaldehyde

目的在LLDPE/CS共混膜表面缩合对羟基苯甲醛,制备表面席夫碱基LLDPE/CS功能包装膜。方法采用L9(33)正交实验探讨反应时间、反应温度及反应物浓度对LLDPE/CS包装膜表面的壳聚糖席夫碱基含量的影响。结果达到表面基团最大含量的最佳反应条件为45℃,对羟基苯甲醛溶液的质量分数为25%,反应时间为12 h。对大肠杆菌、金黄色葡萄球菌和黑曲霉的抑菌实验表明,对羟基苯甲醛席夫碱基LLDPE/CS共混包装膜具有抑菌性所需要的最低基团含量分别是0.1,0.2,0.3 mmol/cm2,且随着表面席夫碱基团含量增加而增加。结论 FTIR和1H NMR分析结果表明,表面基团具有席夫碱的结构特征。

Objective Schiff base LLDPE/CS functional packaging films were prepared by a condensation reaction of phydroxybenzaldehyde and chitosan （CS）. Methods The optimal conditions of LLDPE/CS films modification were obtained according to [ L9（33） ]. The optimal conditions were as follows： a reaction temperature of 45 ℃ , a p-hydroxybenzalde- hyde concentration of 25% and a reaction time of 12 h. The study on antibacterial activities against Escherichia eoli, Staphlococcus anreus and Aspergillus niger indicated that the lowest antibacterial concentrations of schiff base were 0.1 mmo]/cm2 , 0.2 mmol/cm2 and 0.3 mmol/cm2, respectively, and the antibacterial activities were improved with the increasing contents of schiff base groups on the surface. Conclusion FTIR and 1H NMR showed that there were schiff base groups on the films.