(RSC Advances) Understanding the Crystallization Behavior of Polyamide6/Polyamide66 Alloys from the Perspective of Hydrogen Bonds: Projection Moving-Window 2D Correlation FTIR Spectroscopy and the Enthalpy
writer：Yanan Ma, Tao Zhou,* Gehong Su, Yan Li, and Aiming Zhang
keywords：Crystallization, nylon, hydrogen bonds, Projection moving-window 2D correlation FTIR spectroscopy
source：期刊
specific source：RSC Advances, 2016, 6, 87405–87415
Issue time：2016年
In this study, the crystallization behavior of PA6/PA66 alloys was studied using in situ FTIR spectroscopy combined with Proj-MW2D correlation analysis and DSC measurements. The method of calculating the generation enthalpy of hydrogen bonds during PA6/PA66 alloys crystallization was also established via Van’t Hoff analysis. The essential reason of the crystallization reduction for both PA6 and PA66 in alloys was elucidated from the perspective of hydrogen bonds. Compared with neat PA6 and neat PA66, DSC measurements found the crystallization ability of both PA6 and PA66 in the alloys obviously decreased. From the results of the generation enthalpies of hydrogen bonds, it was confirmed that the capability of hydrogen bonds generation of both PA6 and PA66 in PA6/PA66 alloys is significantly reduced. The molecular chains motions of PA6 and PA66 during the alloys crystallization are successfully separated using Proj-MW2D correlation FTIR spectroscopy. Two main issues were addressed. The first one is that the generating capacity of hydrogen bonds between PA6 and PA66 is actually very weak, although this type of hydrogen bonds can be generated in theory. The second one is that non-hydrogen bonded molecular chains of PA66 are also involved in the PA6 crystallization, and the molecular chains of amorphous state PA66 hinder the generation of hydrogen bonds between PA6 molecular chains, resulting in a significant crystallization reduction of PA6 in PA6/PA66 alloys.