纳米CaCO3原位改性对壳聚糖复合涂膜性能的影响

Influence of the in-situ Modification of Nano-CaCO3 on the Properties of Composite Chitosan Coatings

摘要:

以硬脂酸钠为原位改性剂，采用流延法制备了原位改性纳米CaCO3/壳聚糖复合涂膜。以机械强度(Ts、EB)、水蒸气透过率(WVP)、氧气透过率(OP)、二氧化碳透过率(CDP)、水溶性、吸水率、抑菌性为检测指标，研究了原位改性工艺条件对纳米CaCO3/壳聚糖复合涂膜性能的影响。研究结果表明，当改性温度为80 ℃，改性时间为40 min时，纳米复合涂膜的拉伸强度显著提高，其对氧气、水蒸气的阻隔能力提高，对二氧化碳阻隔能力下降，涂膜透光性提高，表明壳聚糖与CaCO3的相容性增强，工艺条件对复合涂膜性能影响显著。此外，改性温度对铜绿假单胞菌和粘质沙雷氏菌的抑菌效果影响显著，但改性时间基本不影响涂膜对铜绿假单胞菌的抑菌效果，这可能与纳米复合涂膜聚合物分子对两种菌的作用方式或菌内酶作用有关。

Abstract:

Nano-CaCO3-chitosan composite coatings were prepared by the tape-casting process with sodium stearate as an in-situ modifier. The influence of the conditions during in-situ modification on the properties of the composite coatings was studied in terms of mechanical properties (Ts and EB), water vapor permission (WVP), O2 permeability (OP), CO2 permeability (CDP), water solubility, water absorption, and antibacterial activity. The results showed that when the conditions for nanocomposite coating in situ was changed to 80 ℃ for 40 min, the tensile strength of the composite coatings improved significantly, barrier properties against moisture and O2 increased, CO2-barrier property decreased, and coating transmittance improved. These observations indicated that the compatibility between chitosan and CaCO3 was increased and the modification conditions significantly affected the performance of the composite coating. In addition, the modification temperature had a significant impact on the antibacterial activity of the coating against Pseudomonas aeruginosa and Serratia marcescens, whereas the modification time hardly affected the antibacterial activity against P. aeruginosa. This could be related to the mode of action of the polymer molecules in the nanocomposite coatings on the two types of bacteria or bacterial enzyme activity.