Designing Benign Polybenzoxazines for Near Superhydrophobic and Corrosion Protection: A Sustainable Approach Toward High‐Performance Applications
Mythili Settu, Balaji Krishnasamy, Thangaraju Dheivasigamani, Rathika Govindasamy, Kailasam Saravana ManiABSTRACT
Three structurally distinct benzoxazine monomers are synthesized using a new kind of bisphenol (PC) from phenol (P) and a sustainable source of citronellal (C). A different nature of amines, furfurylamine (ffa), octadecylamine (oda), and (3‐aminopropyl)triethoxysilane (aptes), were separately reacted with PC by following Mannich condensation to synthesize benzoxazines. Spectral analyses confirm the successful formation of bisphenol PC and benzoxazine monomers (PC‐bz). The lowest polymerization temperature of 237°C was found for PC‐oda due to its long aliphatic chain, which attentively involves the curing process. Based on Kissinger and Ozawa methods, a DSC curing kinetic study for PC‐oda was performed and the activation energy (E a ) was found to be 117.69 and 120.30 kJ mol −1 , respectively. Thermal stability of poly(PC‐aptes) showed up to 466°C and the highest char yield of 30% at 850°C in addition to the LOI values of 29 due to enhanced cross‐linking density. Hydrophobic studies showed that poly(PC‐aptes) possess the highest water contact value of 156°, reflecting near superhydrophobic behavior. The corrosion protection efficiency of 99% was established by the poly(PC‐aptes); the results revealed that polybenzoxazine coating on mild steel has exceptional surface protection. The data from the computational DFT studies have been correlated with the results of the corrosion studies and validated.