Microwave‐Assisted Sustainable Synthesis of Telechelic Poly(ethylene glycol)s with Benzoxazine End Groups

Abstract

AbstractA microwave assisted synthetic route was explored as a sustainable tool for the preparation of cross‐linkable telechelic poly(ethylene glycol)s endcapped with benzoxazine functionality. In comparison to the conventional methodology, the reaction completion time could be significantly reduced using MAS technique and the sustainability of the procedure was improved. Microwave active bifunctional amines were prepared by the condensation reaction of p‐aminobenzoic acid and poly(ethylene glycol)s of different chain lengths to yield amine terminated poly(ethylene glycol)s (ATPEGs). Cardanol, an agro‐waste was chosen as the phenolic source, which was reacted with ATPEG to undergo Mannich like condensation resulting in reactive thermoplastic of telechelic nature. The structure of the resulting polymer was confirmed through FT‐IR and 1H‐NMR spectroscopy. Benzoxazine moieties present at the terminals undergo thermally accelerated ring opening polymerization to form cross‐linked networks which was studied using non‐isothermal differential scanning calorimetry (DSC). The rheological behavior of the resulting polymer suggests that the viscosity of the benzoxazine‐endcapped telechelic poly(ethylene glycol)s is sufficiently low to permit solventless processing which can be credited to the presence of flexible polyether linkages. The adhesive properties of the cross‐linked benzoxazine endcapped telechelic poly(ethylene glycol)s have also been studied.