In Situ Observation of γ-to-α Structural Transformation in Bio-Based Nylon 5,6 Fibers via X-Ray Diffraction and DFT...

Area of Science:

• Materials Science
• Polymer Science
• Crystallography

Background:

• Bio-based nylon 5,6 fibers are gaining attention as sustainable alternatives to conventional plastics.
• Understanding their crystalline structure and phase transformations is key to optimizing material properties.

Purpose of the Study:

• To investigate the in situ structural transformation from the gamma-phase to the alpha-phase in nylon 5,6 fibers during uniaxial stretching.
• To elucidate the mechanism of this phase transition using experimental and theoretical methods.

Main Methods:

• In situ uniaxial stretching combined with X-ray diffraction (XRD) analysis.
• Density functional theory (DFT) calculations to determine phase stability.

Main Results:

• Nylon 5,6 fibers initially exhibit a dominant gamma-phase crystalline structure.
• Uniaxial stretching induces a continuous transition to the alpha-phase, evidenced by increasing alpha(004) peak intensity.
• DFT calculations confirm the alpha-phase is thermodynamically more stable than the gamma-phase.

Conclusions:

• The study provides a comprehensive understanding of the gamma-to-alpha phase transition mechanism in nylon 5,6 fibers.
• The findings offer insights for tailoring nylon fiber properties through controlled crystal phase engineering.
• This research contributes to the development of high-performance, eco-friendly nylon materials.