Effect of hydrogen bond on phase transition behavior of polyamides during stretching process

Abstract During the fiber spinning process, the stretching process is the key to improve the mechanical properties of materials. It is very important to study the effect of hydrogen bond density on the aggregation structure evolution of polyamide for the preparation of high-performance fibers. In this paper, three kinds of polyamides (polyamide 6, polyamide 612 and polyamide 1212) were comparatively studied. In these three polyamides, the hydrogen bond density showed a gradient trend. With the increase of hydrogen bond density, the tensile strength and crystallinity of the materials gradually increased. The phase transition process of the three polyamides had significant difference. This was due to the difference of hydrogen bond density which resulted in different thermally stability of crystal blocks. Finally, the phase evolution schematic of polyamides depending on hydrogen bond density and stretching strains was established.