取向条件下N-甲基壳聚糖溶液浇铸膜中晶片聚集体的形成

用正交偏光显微镜观察取向了的硼(N-甲基壳聚糖)=30％的N-甲基壳聚糖／甲酸溶液浇铸膜中一种特殊的结晶形态．晶片呈圆形堆砌．其聚集体的直径为几十微米．晶片聚集体内晶片无规取向．但晶片聚集体整体沿剪切方向取向．扫描电镜和X光衍射实验证实了取向浇铸膜中晶片的这种堆砌方式．这种形态是先取向后结晶形成的．

The Formation of Lamellar Aggregates in Oriented N-Methyl Chitosan Solution Cast Film

Chitin is one of the important natural polymers constituting the shells of crustaceans and the cell walls of many fungi.Chitosan is an N-deacetylation product of chitin.Some authors have reported the crystalline morphology of chitosan derivatives,but few concerned with the crystalline morphology in oriented state.In this article,the crystalline morphology of oriented films cast from 30wt% N-methyl chitosan/formic acid was observed by means of cross polarized optical microscopy.The crystals formed after the orientation of solution cast film.The diameter of the special lamellar aggregates observed was several ten microns.The lamellar oriented randomly within the aggregates,but the lamellar aggregates oriented in its entirety along the shearing direction.The lamellar aggregates were completely different with spherulites.The former was on the surface of the cast films, but the latter was inside the cast films.The coexistence of lamella aggregates and spherulites can be noticed in some regions.Scanning electron microcopy and X-ray diffraction experiments proved this packing mode of lamellar in the oriented solution cast film.The formation mechanism was explained by memory of molecular order in the concentrated solution after shear.