Polyurethane Foams Loaded with Carbon Nanofibers for Oil Spill Recovery: Mechanical Properties under Fatigue Conditions and Selective Absorption in Oil/Water Mixtures

Marine pollution due to spillage of hydrocarbons represents a well-known current environmental problem. In order to recover the otherwise wasted oils and to prevent pollution damage, polyurethane foams are considered suitable materials for their ability to separate oils from sea-water and for their reusability. In this work we studied polyurethane foams filled with carbon nanofibers, in varying amounts, aimed at enhancing the selectivity of the material towards the oils and at improving the mechanical durability of the foam. Polyurethane-based foams were experimentally characterized by morphological, surface, and mechanical analyses (optical microscopy observation, contact angle measurement, absorption test according to ASTM F726-99 standard and compression fatigue tests according to ISO 24999 standard). Results indicated an increase in hydrophobic behavior and a good oleophilic character of the composite sponges besides an improved selective absorption of the foam toward oils in mixed water/oil media. The optimal filler amount was found to be around 1 wt% for the homogeneous distribution inside the polymeric foam. Finally, the fatigue test results showed an improvement of the mechanical properties of the foam with the growing carbon filler amount.