Nanocomposites and nanomaterials

Synergistic effect of the strength increasing of fiberglass by reinforcing epoxy binder with carbon nanotubes
Kartel M.T.1,3, Sementsov Yu.I.2,3, Cherniuk O.A.3, Grebelna Yu.V.3, Ivanenko K.O.4, Makhno S.M.2,3, Zhuravskyi S.V.2,3
1Ningbo University of Technology, 201 Fenghua Road, Ningbo, 315211, China
2Ningbo Sino-Ukrainian New Materials Industrial Technologies Institute, Kechuang building, N777 Zhongguan road, Ningbo, 315211, China
3O. Chuiko Institute of Surface Chemistry, National Academy of Sciences of Ukraine, 17 General Naumov Str., Kyiv, 03164, Ukraine
4Institute of Macromolecular Chemistry, NAS of Ukraine, 48 Kharkiv highway, Kyiv, 02160, Ukraine
E-mail: ysementsov@ukr.net

By modifying carbon nanotubes (CNTs) with oxygen heteroatoms, it is possible to change their reactivity. According to XPS , the oxygen content in CNTs after anodically oxidized (30 - 200 Ah/kg) in concentrated sulphuric acid samples varies with a certain relative distribution of oxygen-containing groups characteristic of oxidized carbon materials depending on the amount of electricity passed. The maximum oxygen content is 1.65% at. after skipping 90 Ah/kg. At the same time, the specific surface area is decreased from ~ 225 to ~ 205 m2/h. Reinforcement of epoxy resin brand LR 285 by mixing with oxidized CNTs on the mixer with three rolls for two-layer sample of fiberglass increases the its tensile strength  by 59%, and the initial CNTs by ultrasound in amine hardener LH 286 - by 54%. If, at the same time, oxidized CNTs and initial CNTs are reinforced into resin and the hardener in the same amount as in first time, a synergistic effect is observed: the strength limit is almost doubled. This effect is explained by the fact that the amine hardener in the interaction with CNTs acts as a surfactant. In this case, it orients the hydrocarbon part to the CNTs, and the amino groups - outwards, which confirms our quantum chemical calculations [1]. The resulting surface layer prevents reverse agglomeration of CNTs after dispersion. Because, it is the amino groups that react with the epoxy groups of the resin, the interaction of the polymer matrix with the surface of the CNT is enhanced. For oxidized CNTs, the opposite is true. In the case of dispersion of oxidized CNTs in the resin, the most oxygen-containing groups on the surface of CNTs (due to their polarity) prevent reverse agglomeration after dispersion.
1.	Cherniuk O.A., Demianenko E.M., Terets M.I. et al. Study of the mechanism of influence of carbon nanotubes surface chemistry on the mechanical properties of fiberglass // Appl Nanosci.-2020.-10.P. 4797–4807.