International audienceA comprehensive analysis of electrical, electromagnetic (EM), mechanical, and thermal properties of epoxy resin composites filled with 0.25-2.0wt. % of carbon additives characterized by high surface area, both nano-sized, like carbon nanotubes (CNTs) and carbon black (CBH), and micro-sized exfoliated graphite (EG), was performed. We found that the physical properties of both CNTs- and CBH-based epoxy resin composites increased all together with filler content and even more clearly for CBH than for CNTs. In the case of EG-based composites, good correlation between properties and filler amount was observed for concentrations below 1.5 wt. %. We conclude that CBH and, to a lower extent, EG could replace expensive CNTs for producing effective EM materials in microwave and low-frequency ranges, which are, in addition, mechanically and thermally stable

We report high mechanical, dielectric, and thermal performance of carbon nanotubes (CNT) reinforced ethylene vinyl acetate (EVA) composites, fabricated using conventional melt extrusion processing. CNT have extremely high stiffness, electrical conductivity, and surface area, ensuring strong interactions with the polymer and effective reinforcement. The addition of CNT to EVA leads to an extremely high yield strength and Young’s modulus of the composites. The EVA composite produced, containing 5 wt% CNT, exhibited an almost 3-fold increase in Young’s modulus and a 2.2-fold improvement of yield strength compared to neat EVA. However, the composite maintained high deformation properties—a ductility of 1300%. Scanning electron microscopy analysis evidences the agglomeration of the CNT in the EVA/CNT composites. The EVA/CNT composites gained excellent electrostatic discharge properties—a surface resistivity in the range of 108 Ω/square. The observed thermal conductivity of the composites was increased by about 30% without losing the electrically insulating performance.

Oat and spelt husks (OH and SH, respectively) lignocellulosic biomass derived fillers have been compared with commercial wood flour (WF) in respects to their morphology, chemical composition, bulk density, aspect ratio, and thermal stability. OH and SH have been obtained by both mechanical milling and steam explosion auto‐hydrolysis treatment at various processing conditions. Reinforcement efficiency of OH and SH derived lignocellulosic biomass fillers on the flexural properties of maleic acid‐grafted polypropylene (PPgMA) compatibilized polypropylene (PP) composites is compared with that of WF. The compatibilized PP composites have been manufactured by melt compounding. Flexural test specimens of the compatibilized PP composites have been manufactured by injection molding. It has been demonstrated that both the husks derived lignocellulose fillers can be used to improve flexural modulus and maximal flexural strength of PP, although its modifying effect is somewhat smaller in comparison to WF reinforcement, most probably due to higher cellulose content of the latter. Husks derived lignocellulose filler‐reinforced PP composites, however, demonstrate increased flexibility in comparison to WF‐filled systems. POLYM. ENG. SCI., 59:2467–2473, 2019. © 2019 Society of Plastics Engineers

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The work demonstrates selected results of the investigations on surface properties and wear resistance of polypropylene based wood-polymer composites (WPC) reinforced with wood flour. WPC are broadly applied in construction and automotive sectors, where mechanical, thermal as well as moisture absorbing characteristics are of great importance. In order to get information about wear resistance of such composites Taber wear test is applied. Surface properties are investigated before and after tribological test. Contact angle values of the investigated compositions are compared after different wear periods (0, 2000, 5000 and 10000 cycles) with abrasives H22 and CS17.