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Nanocomposites of polypropylene and graphene nanoplatelets were synthesized by in situ polymerization in liquid monomer in the presence of highly effective isospecific homogeneous metallocene catalyst. Microstructure, mechanical, dielectric, and thermal properties of composites are presented. X-ray phase analysis data indicate that graphene nanoplatelets are present in composites as thin flaky particles aggregates, with aspect ratio affected by sonication of reaction mixture. Crystallization tempera- ture of polypropylene increases in composites. Nanocomposites are characterized by high rigidity, thermal stability, and crystalliza- tion temperature, low conductivity, and high dielectric losses in the microwave range. V C 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 127: 904-911, 2013

The increase of realization coefficients of components in composite materials (CM), especially conducting (CCM), is becoming a high-priority task. Designing a CCM is usually carried out by changing the concentration of functional fillers. At the same time another method is equally reasonable, that is, preliminary modification of fillers allowing one to control the properties of CCM over a wide range at the same filler concentration. The aim of this work was to elucidate the structure of CCMs containing short carbon fibers (CF) having different HTT in the range 750--2,200 C and to study their electrophysical properties.

Novel polyethylene- and polypropylene-based electromagnetic wave shielding and absorbing composite materials with low combustibility, enhanced thermal and mechanical properties, containing graphite, grinded wood, and fire retardants, were developed and investigated. Flame-resistance, thermal and mechanical properties of these materials was investigated. Electromagnetic wave reflection coefficients over the frequency range 20–40 GHz were measured; at moderate concentration (10–15%) of functional filler, reflection coefficient can be as low as −16 dB for PE and −11 dB for PP composite, respectively. Coke formation mechanism was investigated, the principal role in this process is attributed to aromatization and condensation of aromatic compounds with the formation of polycyclic aromatic systems, an important role of phosphoric acids in accelerating this process was found. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010