Ambient temperature polymerisation of oxiranes initiated by the novel MSbF6/H2O co-initiator system

The first example of leveraging the potent, but dormant, acidity of hexafluoroantimonate by its facile hydrolysis reaction to initiate cationic curing of oxirane monomers is described. This could be applied in adhesive formulations ‘on demand’. The desirable curing reaction always coexists with the detrimental cyclic dimerisation. An in depth mechanistic study of the reaction demonstrates the conditions required to optimise the desirable curing process. Hence, the detrimental cyclic dimerisation pathway can be avoided by fine tuning the quantity of water, in the MSbF6/H2O co-initiator system, in conjunction with the type of oxirane (external vs. internal). External oxiranes (DER 331 and Glycidyl Phenyl Ether, GPE) experience a rise in the amount of gelation with declining water loadings, whereas internal oxiranes (CER 4221 and cyclohexene oxide) show the converse dependency on water. This methodology enables one to formulate highly desirable one-component adhesives.