Epoxy resins containing epoxy-modified polyrotaxanes

The toughening of epoxy resins is important for their applications in coatings, adhesives, and composite materials. In our previous study, we introduced polyrotaxane (PR), which comprises poly-ε-caprolactone (PCL)-grafted α-cyclodextrins (α-CDs) and a polyethylene glycol (PEG) axial chain, into epoxy resins as an additive and observed that the presence of PR causes an additional viscoelastic relaxation and enhances the mechanical toughness. In this study, we modified the side chain ends of PR with epoxy groups (PR-E) to enable incorporation into crosslinked epoxy networks. The chemical bonding of PR-E to the epoxy resins suppressed the local dynamics of the PCL graft chains and enhanced the mechanical properties.