The Crystallization Behavior Regulating Nature of Hydrogen Bonds Interaction on Polyamide 6,6 by Poly(vinyl pyrrolidone)

The crystallization behavior of polyamide 6,6 (PA66) under complex flow field is of great importance for its final mechanical properties. Poly(vinyl pyrrolidone) (PVP) was applied as crystallization modifying agency to improve processability of PA66. The regulation nature on hydrogen bonds (H-bonds) interaction of PVP was studied upon cooling process. As revealed by in situ FTIR, the sample with 5 wt% PVP displays decreased enthalpy change (Delta H) for both the generation of H-bonds and the transition of H-bonds from disordered to ordered state, which illustrates the molecular mechanism for the regulation of crystallzation behavior. Moveover, 2D-WAXD is applied to reveal the evolution of microstructure for sample under external injection field. Hermans orientation factor (f(H)) decreases obviously with the addition of PVP, because the relaxation of chain segments is promoted as well the crystallization is retarded. The above crystallization and microstructure changes during the processing provokes the improvement of processability without the apparent sacrifice of mechanical properties.

Automated summary

The crystallization behavior of polyamide 6,6 (PA66) under complex flow field was studied with the addition of poly(vinyl pyrrolidone) (PVP) as a crystallization modifying agent. The regulation of hydrogen bonds interaction by PVP was investigated, and the microstructure evolution under external injection field was revealed. The changes in crystallization and microstructure during processing led to improved processability without sacrificing mechanical properties.