纤维的工程应用开避了纤维科学和工业发展的新前景,使得纤维的形变和断裂行为成为迫切需要深入了解的课题。本文是纤维形变和断裂行为系列文章的一部分,报道纤维素纤维拉伸下的断裂行为,包括断裂过程和断裂机理。用一特殊装置在SEM样品室中拉伸单纤维,观察纤维形变和断裂情景,並摄取过程的系列电子显微图。实验显示了这类纤维拉伸下裂缝发生、发展和最终断裂的形态。这类纤维可能产生两种类型的裂缝。一类由于大分子间次价键的断裂导致原纤间分离而形成;另一类由于大分子主价键断裂导致原纤断裂而形成。后一类是最终使纤维破坏的主裂缝。下图为一原棉纤维拉伸过程的系列电子显微照片, The application of fiber engineering has opened up new prospects for the development of fiber science and industry, making the deformation and fracture behavior of fiber an urgent need for in-depth understanding of the subject. This article is part of a series of articles on fiber deformation and fracture behavior reporting the fracture behavior of cellulose fibers under tension, including fracture processes and fracture mechanisms. A special device was used to stretch single fibers in a SEM sample chamber to observe fiber deformation and fracture scenarios and to take a series of electron micrographs of the process. Experiments show the morphology of these fibers under tension, fracture and fracture. Such fibers may produce two types of cracks. One kind of macromolecules due to the break of the secondary valence bond leading to the separation between the fibrils; the other is due to the breakage of the primary valence bond of the macromolecule resulting in the breakage of the fibrils. The latter category is the main fracture that ultimately disrupts the fibers. The picture below shows a series of electron micrographs of a raw cotton fiber drawing process,