Styrene-Maleic Anhydride Copolymer-Based Ultralight and High-Performance Foam via Ambient Pressure Drying of Hydrogel Foam

Developing advanced strategies that are easy to implement and highly energy-efficient to prepare high-performance polymer foams is of paramount importance for practical applications. Here, we report a method that can transform low-value styrene-maleic anhydride copolymer into high-value polymer foam through a simple and low-energy-consuming process. SMA was prepared via self-stabilized precipitation polymerization (2SP), followed by partial ammonolysis, mechanical foaming, and chemical cross-linking to obtain hydrogel foams. The hydrogel foams were then converted into ultralight and high-performance polymer foams using low-energy ambient pressure drying and imidization at 180 °C. The obtained polymer foams have ultralow density (0.028 ± 0.003–0.049 ± 0.004 g/cm3), high porosity (93.38–95.28%), low thermal conductivity (0.030 ± 0.001–0.034 ± 0.002 W/m K), excellent cyclic compressibility, and strong oil absorption capacity (up to 20.3 ± 1.0 g/g). Owing to the simplicity and efficiency of the present strategy, as well as the structural diversity and superior performance of maleic anhydride copolymer-based foams, widespread application in diverse fields such as building insulation materials can be expected.