Superhydrophobic and superelastic thermoplastic polyurethane/multiwalled carbon nanotubes porous monolith for durable oil/water separation

Absorbing materials with high hydrophobicity, porosity and mechanical resilience are urgently needed for oil/water separation. In this work, three dimensional (3D) porous thermoplastic polyurethane-based (TPU) composite monoliths with hierarchical porous structure were prepared by a feasible thermally induced phase separation (TIPS) method. The morphology analysis revealed the hierarchical porous structure was effectively perfected by adding 2 wt% carboxyl multiwalled carbon nanotubes (cMWNTs), which showed a uniform dispersion and compatibility in TPU skeleton. As a result, the hydrophobicity (151 degrees), saturated adsorption capacity (6.9-42.3 g g(-1)) and mechanical compression and resilience property of TPU/cMWNTs monolith were improved significantly when comparing to pure monolith. Moreover, the composite monolith could maintain stable hydrophobicity and absorption capacity in corrosive environment. Besides, arising from the excellent mechanical elasticity, the monolith can be easily reused by absorbing-squeezing cycles. The recycled monolith can maintain high separation efficiency of 98.4% even reusing 40 cycles. As a kind of highly efficient absorbent, porous TPU/cMWNTs monolith shows great prospect in the application of large-scale oil/water separation.