Synthesis of mechanically reinforced silica aerogels via surface-initiated reversible addition-fragmentation chain transfer (RAFT) polymerization

Abstract

Mechanically reinforced polymer–silica aerogels have been successfully prepared by using surface-initiated reversible addition-fragmentation chain transfer polymerization. With this approach, well-defined polystyrene (PSt) and poly(butyl acrylate) (PBA) with low polydispersities grew on the silica surface and improved the mechanical strength in relation to native aerogels. Moreover, it allowed establishing a structure–property relationship between the grafted polymer molecular weight and physical properties of the hybrid aerogels, thereby enabling the preparation of composites with tailored properties. The aerogel composites here obtained exhibited a low density of 0.13–0.17 g cm⁻³, high thermal insulation performance of 0.03–0.04 W m⁻¹ K⁻¹ and a high specific surface area of 350–780 m² g⁻¹, with approximately one order of magnitude improvement in the compression strength over the non-reinforced aerogels.