Abstract:

In order to establish the erlationship between the microstructure and mechanical pwoperties of polyester industrial yarns, it is very important to develop an effective test method. Two-dimensional X-ray diffraction method was used to study the crystallinity, crystal orientation and its relationship with the properties of polyester industrial yarns, including high tenacity type (HT), low shrinkage type (LS) and super low shrinkage type (SLS). The results show that the SLS with maximal crystallinity, maximal grain size and minimum ouientation is the smallest in dry heat shrinkage ratio and the best in dimension stability. Additionally, the largest breaking strength and the minimum elongation at break of the HT are ascribed to its minimum crystallinity, minimum grain size and maximal orientation. Accordingly, it cab be concluded that the crystallinity and grain size mainly influence the influence the dry heat shrinkage ratio of polyester industrial yarns, and the crystal orientaion mainly influence the breaking strength, elongation at break and elastic modulus of the fibers.

Key words: 2-D X-ray dkffeaction, polyester industrial yarn, crystallinity, orientation