Revealing the Combined Nanoconfinement Effect by Soft and Stiff Inclusions in PMMA/Silica CO2 Blown Foams

This study shows the importance of nanoparticle (NP) spatial arrangement on the nucleation, morphology, and properties of nanocomposite foams. It probes CO2 blown PMMA with three types of nanosilica structures with exactly the same chemical composition: aggregates, chain bound clusters, and individually dispersed NPs. A systematic but nontrivial scaling of morphology, glass transition temperature, static and impact mechanical properties, and thermal conductivity is discussed with special regard to the combined nanoconfinement by soft and stiff inclusions. The presented results suggest a limited potential of simultaneous toughening by nanoreinforcement and shear banding, which can draw significant implications for both the fundamental science and industrial practice dealing with nanoreinforced cellular materials. This study is focused on the combined nanoconfinement effect from soft and stiff inclusions in polymer nanocomposite foams. Nanoparticle dispersion quality, characterized by the effective surface area of nanoparticles exposed to the interaction with polymers over the interelement distances, is correlated with the cell morphology, glass transition temperature, static and impact mechanical performance, and heat conductivity.