Sustainable Strategy of Thymol‐Based Polybenzoxazines with Enhanced Thermal Stability, Hydrophobicity, and Corrosion Resistant Properties

Two series of thermally stable, superhydrophobic polybenzoxazines were synthesized from thymol based bisphenols namely Tf and Tc with five different amines namely furfurylamine (ffa), aniline (an), amantadine (ama), octadecylamine (oda), allylamine (ala). Synthesized bisphenols (Tf, Tc) and benzoxazines molecular structures were confirmed by spectral analyses. Thermal behavior of benzoxazines was analyzed using DSC and TGA. The lowest curing temperature of 202 0 C and 203 0 C for Tf‐an and Tc‐an were noted respectively. Poly(Tf‐ffa) in Tf series and poly(Tc‐ffa) in Tc series exhibited the highest char yield of 40% and 35% respectively with increase in LOI. The corrosion resistant property for all polybenzoxazines showed an efficiency of 99.99%. The experimentally obtained corrosion values are compared theoretically using density functional theory (DFT). The antimicrobial activity of Tf‐ffa possess 18 mm inhibition zone revealing its high bacteriostatic property. Among the five polybenzoxazines in each series poly(Tf‐an) and poly(Tc‐ama) showed highest water contact angle values of 154 0 and 143 0 respectively. This hydrophobic nature was further explored for oil‐water separation application which has the separation efficiency of 97% for poly(Tf‐an) and 96% for poly(Tc‐ama). Results from different studies infer that the developed materials can be suitably exploited in the field of corrosion resistance and hydrophobic coating applications.