Replacing bisphenol-A with bisguaiacol-F to synthesize polybenzoxazines for a pollution-free environment

Abstract

In recent years, bisguaiacol F (BGF) is considered as a green alternative to bisphenol A (BPA). The present work deals with the synthesis of BGF and BGF-based benzoxazines, viz., bis[(3-(furan-2-yl) methyl)-3,4-dihydro-2H benzoxazin-6-yl]methane and bis[(3-octadecyl)-3,4-dihydro-2H benzoxazin-6-yl]methane, as an alternative to BPA and polybenzoxazines derived from BPA. A solventless method was adopted for the synthesis of BGF and the benzoxazine monomers. The structure and purity of BGF is confirmed by FT-IR, NMR (¹H and ¹³C), MS and GC. The monomers were polymerized via ring opening polymerization by heating as shown by FT-IR (disappearance of the peak due to the oxazine ring at 933 cm⁻¹). Differential scanning calorimetric (DSC) analysis of the monomers shows a wide range of processability between 77 and 122 °C. Thermal properties of the furfurylamine based polybenzoxazine (BGF-FPbz) and stearylamine based polybenzoxazine (BGF-SPbz) were investigated by thermogravimetric analysis (TGA). The results indicate that BGF-FPbz shows the maximum thermal stability when compared with BGF-SPbz. Both the polymers exhibit good flame retardant properties as shown by their LOI values (more than 26).