Kinetics of Void Closure of PS/PMMA Core–Shell Lattices during Dry Sintering

The formation of continuous films from latex particles with high glass transition temperatures (<i>T</i>_<i>g</i>) via dry sintering encompasses a series of processes: initial particle packing, deformation, void closure, and interdiffusion of polymer chains. Gaining an understanding of the structuring processes at these stages is crucial for obtaining the optimal film properties required in coatings, adhesives, and advanced materials. In this work, the kinetics of the structural evolution of polystyrene/poly(methyl methacrylate) (PS/PMMA) core-shell latex particles with varying PS and PMMA compositional ratios during thermal annealing was investigated by means of a small-angle X-ray scattering technique. The process of void closure within the latex films has been analyzed using the Avrami equation to extract kinetic parameters. This approach generated a characteristic half-time for the void closure (<i>t</i>_1/2), which was then used to calculate the apparent activation energy of the process. This study offers valuable insights for the rational design and optimization of latex-based films with customized performance characteristics.