• In situ suspension polymerisation tailors PS–sepiolite precursors for foaming. • VTES functionalisation at pH 1 optimises dispersion, interface, and melt reinforcement. • Percolated networks deliver a melt window suitable for efficient CO 2 foaming. • CO 2 foams show 0.6–1.7 μm cells, ∼10 13 cm −3 nuclei, and ∼100% open-cell content. • Specific modulus >7× neat PS at reduced density; morphology finer than melt-mixed.
Frutos et al. (Sat,) studied this question.