Sustainable polymer chemistry of high-performance materials by mechanochemistry Niamh Curran and Stuart James Queen’s University Belfast, Northern Ireland Benzoxazines are an advanced type of phenolic resin with attractive properties for aerospace applications. They are characterised as possessing a relatively long shelf life and offer considerable molecular-design flexibility. The monomers are formed by melt-synthesis, which is typically solventless, followed by ring opening polymerisation to give the polybenzoxazines. 1 The batch reactor processes, currently used to produce benzoxazine monomer and formulations thereof are time and energy intensive and plagued by batch-to-batch variations. Extrusion methods enable scaling of mechanochemical and melt phase synthesis under continuous, solvent-free or low-solvent conditions. Some examples of organic reactions that have been successfully demonstrated using twin screw extrusion (TSE) include Knoevenagel condensation, imine formation, aldol reaction and the Michael addition. 2 TSE has been demonstrated as a suitable reactor technology to synthesize benzoxazines monomers and polymers, but greater understanding is required. Here we will discuss the use of TSE to form benzoxazine monomers. References 1. D. Allen and H. Ishida, Polymer , 2009, 50 , 613-626 2. D. E. Crawford, C. K. G. Miskimmin, A. B. Albadarin, G. Walker and S. L. James, Green Chem. , 2017, 19 , 1507-1518
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