title: The impact of ultra-low amounts of amino-modified MMT on dynamics and properties of densely cross-linked cyanate ester resins.
abstract: Thermostable nanocomposites based on densely cross-linked cyanate ester resins (CER), derived from bisphenol E and doped by 0.01 to 5 wt. % amino-functionalized 2D montmorillonite (MMT) nanoparticles, were synthesized and characterized using Fourier transform infrared (FTIR), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDXS), wide-angle X-ray diffraction (WAXD), dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), far-infrared (Far-IR), and creep rate spectroscopy (CRS) techniques. It was revealed that ultra-low additives, e.g., 0.025 to 0.1 wt. %, of amino-MMT nanolayers covalently embedded into СER network exerted an anomalously large impact on its dynamics and properties resulting, in particular, in some suppression of dynamics, increasing the onset of glass transition temperature by 30° to 40° and twofold rise of modulus in temperature range from 20°C to 200°C. Contrarily, the effects became negligibly small or even negative at increased amino-MMT contents, especially at 2 and 5 wt. %. That could be explained by TEM/EDXS data displaying predominance of individual amino-MMT nanolayers and their thin (2 to 3 nanolayers) stacks over more thick tactoids (5 to 10 nanolayers) and the large amino-MMT aggregates (100 to 500 nm in thickness) reversing the composite structure produced with increasing of amino-MMT content within CER matrix. The revealed effect of ultra-low amino-MMT content testifies in favor of the idea about the extraordinarily enhanced long-range action of the 'constrained dynamics' effect in the case of densely cross-linked polymer networks.
  82.35.Np Nanoparticles in polymers; 81.05.Qk Reinforced polymers and polymer-based composites; 81.07.Pr Organic-inorganic hybrid nanostructures.
authors.affiliation: Ioffe Physical-Technical Institute, RAS, 194021, St Petersburg, Russia.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Bershtein
authors.affiliation: Institute of Macromolecular Chemistry, NAS, 02160, Kyiv, Ukraine.
authors.forename: Alexander
authors.initials: A
authors.lastname: Fainleib
authors.affiliation: Ioffe Physical-Technical Institute, RAS, 194021, St Petersburg, Russia.
authors.forename: Larisa
authors.initials: L
authors.lastname: Egorova
authors.affiliation: Institute of Macromolecular Chemistry, NAS, 02160, Kyiv, Ukraine.
authors.forename: Kristina
authors.initials: K
authors.lastname: Gusakova
authors.affiliation: Institute of Macromolecular Chemistry, NAS, 02160, Kyiv, Ukraine.
authors.forename: Olga
authors.initials: O
authors.lastname: Grigoryeva
authors.affiliation: Ioffe Physical-Technical Institute, RAS, 194021, St Petersburg, Russia.
authors.forename: Demid
authors.initials: D
authors.lastname: Kirilenko
authors.affiliation: Ioffe Physical-Technical Institute, RAS, 194021, St Petersburg, Russia.
authors.forename: Semen
authors.initials: S
authors.lastname: Konnikov
authors.affiliation: Ioffe Physical-Technical Institute, RAS, 194021, St Petersburg, Russia.
authors.forename: Valery
authors.initials: V
authors.lastname: Ryzhov
authors.affiliation: Ioffe Physical-Technical Institute, RAS, 194021, St Petersburg, Russia.
authors.forename: Pavel
authors.initials: P
authors.lastname: Yakushev
authors.affiliation: Institute of Macromolecular Chemistry, NAS, 02160, Kyiv, Ukraine.
authors.forename: Natalia
authors.initials: N
authors.lastname: Lavrenyuk
keywords: Cyanate ester resins; Dynamics; Montmorillonite; Nanocomposites; Properties