Time-resolved AUSAXS at BL28XU at SPring-8

Area of Science:

• Materials Science
• Polymer Chemistry
• X-ray Scattering Physics

Background:

• Ultra-small-angle X-ray scattering (USAXS) is crucial for analyzing nanoscale structures.
• Time-resolved studies are needed to understand dynamic processes like polymer vulcanization.
• Existing USAXS systems may lack the speed or resolution for certain dynamic material changes.

Purpose of the Study:

• To construct and validate a novel anomalous ultra-small-angle X-ray scattering (AUSAXS) system for time-resolved experiments.
• To investigate the structural evolution of zinc compounds within poly(styrene-ran-butadiene) rubber during vulcanization.
• To demonstrate the system's capability in capturing rapid structural changes at different X-ray energies.

Main Methods:

• Construction of an anomalous ultra-small-angle X-ray scattering (AUSAXS) system with an extended path length (9.1 m) at BL28XU, SPring-8.
• Achieving a minimum scattering vector (q) of 0.0069 nm⁻¹ for enhanced resolution.
• Performing time-resolved scattering profile measurements across 17 X-ray energies within 30 seconds, with rapid energy adjustment and stable beam position.

Main Results:

• The AUSAXS system successfully obtained scattering profiles in the q range of 0.0069 to 0.3 nm⁻¹.
• Time-resolved measurements revealed changes in the energy dependence of scattered intensity during rubber vulcanization.
• Observed changes suggest the transformation of zinc compounds within the polymer matrix during the reaction.

Conclusions:

• The developed AUSAXS system is effective for rapid, time-resolved structural analysis of dynamic processes.
• The study provides insights into the structural changes of zinc compounds during the vulcanization of poly(styrene-ran-butadiene) rubber.
• The findings highlight the potential of AUSAXS for monitoring chemical transformations in materials.