Preparation of highly efficient thermal insulating halloysite nanotubes/polyvinyl alcohol composite aerogel based on a simple freeze‐drying strategy

Abstract The development of high‐performance energy‐saving insulation materials is significant for reducing building energy consumption and promoting carbon neutrality. Aerogels show great potential in energy‐saving insulation. However, their high preparation cost and poor mechanical properties limit their application. Here, based on a simple freeze‐drying strategy, a halloysite nanotubes (HNTs)/polyvinyl alcohol (PVA) composite aerogel is achieved via low‐cost and degradable industrial raw material. In particular, a simple process for changing the properties of HNTs/PVA composite aerogels by regulating the solid concentration. As a result, stable covalent cross‐linking and hydrogen bonding structure between HNTs and PVA, long‐range ordered pore structure with high porosity (97.6%), low density (0.12 g/cm³), and low thermal conductivity (44.333 mW/m K) endow the HNTs/PVA composite aerogel high compressive strength (3.33 MPa), lightweight, and highly efficient thermal insulation properties. This work offers an attractive material for building insulation and carbon neutral.