Abstract:Herein, cardanol-based benzoxazine (C-a) was synthesized from cardanol, paraformaldehyde and aniline and then superhydrophobic film combined with cardanol-based polybenzoxazine and silica nanoparticles (SiO2 NPs) was produced through spinning coating technique and thermal curing method. The chemical structure of C-a benzoxazine monomer was characterized by Fourier Transform Infra-red (FTIR) spectroscopy and Nuclear Magnetic Resonance (NMR). Then, the polybenzoxazine film (PC-a) was fabricated through thermal curing method and surface free energy of PC-a film was 22.5 mJ/m2 after thermal curing at 200 oC for 1 h. The wettability properties of PC-a/SiO2 film were characterized by Optical Contact Angle Meter (OCA). As a result, the water contact angle of pure PC-a film was 104 ± 2 o, showing a hydrophobic property. By incorporating different contents of SiO2 NPs, a “lotus effect” superhydrophobic PC-a/SiO2 film with water contact angle of 166 ± 4 o and water sliding angle of 6o and a “petal effect” superhydrophobic PC-a/SiO2 film with water contact angle of 151 ± 3 o could be both developed. After thermal treatment at 200 oC for 1 h, the water contact angle and sliding angle of PC-a/SiO270 film were 163 ± 4 o and 7 o, respectively. Therefore, the superhydrophobic PC-a/SiO270 film could keep its stable superhydrophobicity with a wide range temperature. Moreover, the as-prepared hydrophobic PC-a film still had hydrophobicity with a water contact angle of 97 ± 1 o and superhydrophobic PC-a/SiO270 film could both keep stable after UV exposure for 8 h. So the hydrophobic PC-a film and superhydrophobic PC-a/SiO270 film both had UV resistant properties. In conclusion, this superhydrophobic film based on cardanol polybenzoxazine shows excellent thermal stability and UV resistant property, which has application prospect in the fields of oil-water separation and anti-corrosion coating.