ИСТИНА

Epoxy-silica vitrimer nanocomposites (VNs) were processed by curing of commercial epoxy monomer 4-epoxycyclohexylmethyl-3,4-epoxycyclohexane-carboxylate ERL-4221 with 4-methylhexahydrophthalic anhydride in the presence of zinc acetylacetonate as a transesterification catalyst and 10-15 nm silica nanoparticles (NPs) with phenyl and anhydride functional groups as a filler. It was demonstrated that the introduction of modified NPs did not hindered the rearrangement of the network topology, which allow to retain the most important properties of vitrimers - ability to reprocessing and remolding as well as to self-healing and welding. Moreover, the NPs strengthen the polymer matrix. Introduction of negligible quantity of modified NPs ([SiO2] = 0. 5 and 1.0 wt. %) leads to increase of strength of welded joint of two assembles of VNs. The materials with anhydride-modified NPs show the highest efficiently of welding: the separation forces for VNs with 1 wt. % of phenyl- and anhydride-modified NPs were 83 and 94 N in comparison with 45 N for epoxy vitrimer. The modification of NPs surface by grafting of phenyl and anhydride functional groups providing non-covalent (Van-der-Vaals interaction) and covalent bonds with epoxy network, respectively, improves their dispersion in polymer matrix and accelerates the relaxation process. This work was supported by Russian Foundation of Basic Research (project #18-53-76007).