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  • Author or Editor: L. Semko x
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Abstract  

In the present paper the effect of the thermoexfoliated graphite (EG) content (0–0.310 parts by volume), constituent mixing conditions (a paddle mixer or a disk-and-screw extruder), annealing and aging on thermodestruction processes of polypropylene (PP)/exfoliated graphite composite materials (CM) by means differential thermal analysis and the thermogravimetric method have been investigated. The studies have shown that thermodestruction processes in CM based on PP and EG ran in air for expense of PP thermodestruction. The characteristics of thermodestruction in CM essentially depend on a regime of making and concentration of components. It is established that processes leading to the formation of less perfect crystalline structures or causing amorphization of PP (including formation of continuous space structures from EG particles, cluster traps) advances thermodestruction. The increase in crystallinity extent of PP favors to the decrease in thermodestruction processes.

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Abstract  

Composite materials (CM) based on poly(ethylene) (PE) and nanocrystalline nickel (Ni) have been produced. The effect of the content of nanocrystalline Ni and processes of structure formation of its particles on a melting temperature (T m), interval of melting, true melting heat (ΔH m), degree of crystallinity (χ) as well as characteristics of CM thermodestruction have been determined by DTA and thermogravimetry techniques. It was found that these characteristics are changed non-linearly when the content of nanocrystalline Ni increases. The most efficient influence of Ni on the above mentioned characteristics was observed for its low content (0.01 volume part of Ni). It was shown that a formation of a branched multifractal cluster of nickel above a percolation threshold favored a decrease in T m, ΔH m, χ of filled PE and a majority of thermal characteristics of CM thermodestruction as well.

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