细纤度蚕丝的力学性质与其微细结构的研究

A STUDY ON MECHANICAL PROPERTIES AND FINE STRUCTURE OF FINE-SIZED SILK FIBER

本文研究了细纤度蚕丝和普通纤度蚕丝在力学性质与微细结构上的差异.用X射线衍射法测定了丝素的结晶度和晶区取向指数,用干涉显微镜测定丝素的双折射率.同时,计算了丝素分子整体的取向指数及非晶区取向指数.实验结果表明,蚕丝在小负荷条件下的力学性质(初始模量、屈服强度和屈服伸长率)主要取决于丝素的非晶区取向指数;蚕丝在大负荷条件下的力学性质(断裂强度、断裂伸长率)则决定于丝素分子整体的取向指数.上述力学性质与丝素的结晶度之间似不存在明显的依存关系.

In this paper ,the contrasts were made between fine-sized and ordinary-sized silk fibers in their mechanical properties and fine structure. The crystallinity and the degree of the crystal orien- tation of silk fibroin were measured by X-ray diffraction. The birefringence of fibroin was deter- mined with interference microscope. We also calculated the degree of the total molecular orientation and that in the amorphous region. The experiments showed that the mechanical properties under the condition of light load such as elastic modulus, yield strength and elongation were mainly determined by the degree of the molecu- lar orientation in amorphous region; and under the condition of heavy load, such as breaking strength and elongation were determined by the degree of the total molecular orientation. The exis- tance of the interdependence between the abovealmentioned properties and the crystallinity was not clear.