High mechanically enhanced and degradable polybenzoxazine/polyhexahydrotriazine IPN aerogels by atmospheric drying

Oily wastewater and oil spills pose a threat to the environment and human health, and absorbing these harmful organics through porous aerogel materials is an efficient method for oil/water separation. Herein, we design degradable, hydrophobic, and mechanical 4,4′-methylenedianiline polybenzoxazine/silicone-based polyhexahydrotriazine aerogels (BOZ/Si-PHT) for efficient oil/water separation. The BOZ/Si-PHT interpenetrating network (IPN) aerogels were successfully prepared by sequential polymerization, followed by atmospheric drying without any additional post-processing. The as-prepared BOZ/Si-PHT aerogels exhibit prosperous hydrophobicity (a water contact angle of 121.5°) and good mechanical properties (a compressive strength of 449.6 kPa). Meanwhile, the BOZ/Si-PHT aerogels possess good absorption capacity of oils or organic solvents ranging from 4.6 to 16.3 times their own weights. More importantly, the BOZ/Si-PHT aerogels show rapid degradation after use. This work provides simple, environmentally friendly and sustainable materials for oil/water separation and the rationally designed hydrophobic BOZ/Si-PHT aerogels display enormous potential for practical applications dealing with oily wastewater and oil spills.