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Polymer Sciences
ISSN: 2471-9935
June 04-05, 2018
London, UK
Polymer Congress 2018
Page 19
4
th
Edition of International Conference on
Polymer Science and
Technology
A
series of heterocyclic densely cross-linked hybrid
nanocomposites were synthesized from bisphenol
A-based bisphthalonitrile (BPh) with 0.5wt.% amino-
functionalized montmorillonite (MMT) nanolayers, or amino-
or epoxy-polyhedral oligomeric silsesquioxane (POSS)
nanoparticles. Curing was performed at 260-300°C followed
by post-curing at 340-430°C. The reactive nanoparticles
were covalently embedded into matrix. FTIR indicated
attaining 95% polymerization degree at post-curing and
the appearance of phthalocyanine, triazine and isoindoline
cycles in the network structure. Nanostructure, dynamics
and properties of 0.5 mm thickness films were characterized
using scanning transmission electron microscopy (STEM),
energy dispersive X-ray spectroscopy (EDXS), FTIR and
far-infrared spectroscopy (FIRS), dynamic mechanical
analysis (DMA, 0.1-10Hz), differential scanning calorimetry
(DSC), and thermogravimetric analysis (TGA). TGA/DMA/
DSC measurements were performed in air or nitrogen
mediums. STEM images, EDX spectra and the histograms
of Si nanodistribution indicated satisfactory dispersion and
uniform distribution of POSS nanoparticles (no nanoclusters)
in the matrix. Single MMT nanolayers and 2-3 nanolayers
stacks prevailed in the nanocomposites. TGA indicated slight
thermal degradation starting from 420-430°C, identically
up to 550°C in air and nitrogen mediums. At 550-700°C,
TGA curves sharply diverged: thermo-oxidative degradation
in air resulted in dropping mass to char residue of 4-7%
whereas 72-74% residual was registered in nitrogen. At low
mechanical losses (tan≤0.03-0.04), four relaxations were
registered for post-cured samples: non- or low-cooperative
sub-Tg relaxations at 50-100°(I) and 200-250°C(II), and
Tg≈460°(III) and 515-540°C(IV); for cured films, Tg=380-
390°C. Transition IV was displaced to 560°C in nitrogen.
DMA/DSC showed some suppression of matrix dynamics
by nanoparticles: Tg increased by 20-60°C. Glass transition
manifested highly cooperative (“quasi-phase transition”)
behavior with effective activation energy Qact>>1000kJ/
mol. Dynamic modulus of the nanocomposites E’≈(2-3)GPa
decreased by 20-30% at 500°C. After scanning to 570°C in
nitrogen medium, no relaxation spectrum and glass transition
were observed, and E’≈3.2GPa was registered at 20-600°C.
The studied nanocomposites have a perspective for use in
aerospace, microelectronics, etc.
Ultrahigh-temperature phthalonitrile
nanocomposites with functionalized
silicon-based nanoparticles: Structure,
Dynamics and properties
Vladimir A Bershtein
1
, Demid A Kirilenko
1
, Daria
I Markina
1
, Valery A Ryzhov
1
, Pavel N Yakushev
1
Alexander M Fainleib
2
, Kristina G Gusakova
2
and
Olexandr G Melnychuk
2
1
Ioffe Institute – RAS, Russia
2
Institute of Macromolecular Chemistry – NAS, Ukraine
Vladimir A Bershtein, Polym Sci 2018, Volume 4
DOI: 10.4172/2471-9935-C2-010