壳聚糖/累托石纳米复合材料的结构与性能

采用溶液插层法制备了不同累托石含量的壳聚糖/累托石纳米复合材料,研究了累托石含量、层间距对复合材料性能的影响及不同累托石含量的复合材料的热稳定性和抗菌性能.结果表明:壳聚糖分子链插层进入了累托石层间,累托石均匀地分布在壳聚糖基体中;纳米复合材料的性能与累托石的含量和层间距密切相关,当壳聚糖与累托石的质量比为12∶1时插层效果最好;壳聚糖/累托石纳米复合材料的抗菌能力比单一壳聚糖优异,尤其是对革兰氏阳性菌,其抑菌的最小浓度为单一壳聚糖的1/4～1/2,抑菌时间是单一壳聚糖的3～5倍;复合材料对革兰氏阳性菌的抑制作用比对革兰氏阴性菌的强,且随着累托石含量的增加及层间距的增大,抗菌性能越来越强;纳米复合材料的热稳定性优于壳聚糖.

Structure and Properties of Chitosan/Rectorite Nanocomposites

In order to identify the characteristics of chitosan by rectorite, combine the advantages of chitosan with rectorite and open new directions for the application studies of chitosan, chitosan/rectorite nanocomposites were prepared via solution intercalation method and their properties were studied. The results from X-ray diffraction (XRD) and transmission electron microscopy (TEM) showed that the chitosan chains have inserted into the layer of rectorite,rectorite dispersed into chitosan matrix well, the largest interlayer distance of 3.1nm from original 2.45nm was obtained when the mass ratio of chitosan to rectorite was 12:1. Fourier transform infrared spectroscopy (FT-IR) results revealed that there were hydrogen-bonding and electrostatic interaction between chitosan and rectorite. Compared with chitosan, the nanocomposites showed better antibacterial activity, their minimum inhibition concentration (MIC) and inhibition times (ITs) were 1/2-1/4 and 1/4-1/5 times than that of chitosan, respectively, the MICs against Staphylococcus Aureus and Bacillus Subtilis were only 0.0125%(w/v), inhibition time reached more than 120h when 0.05%(w/v) nanocomposite treated Staphylococcus Aureus and Bacillus Subtilis. Furthermore, the nanocomposite powders obtained better thermal stability than chitosan since rectorite possess layered structure and mica layer with high thermal stability exist. Besides, almost all the properties of chitosan/rectorite nanocomposite were related to the content and layer distance of rectorite.