Composite materials are gaining increasing industrial applications worldwide. Composites based on polymers with conductive fillers have been recently in the focus of extensive research primarily because of their growing importance from the point of view of application. Natural polymers based on renewable materials with selected fillers can be used directly as contemporary materials in: electronics, medicine, industry, as contact conductive materials, electromagnetic and radio wave shields, photothermal optical recorders, electronic noses sensitive to certain chemicals, as well as economically acceptable catalysts. In this paper the results of experimental studies of the properties of composite materials based on lignocellulosic matrix (LC) filled with electrolytic copper powder and chemically obtained silver powder are presented. Volume fractions of metal fillers in the composite materials in tested samples were varied in the range of 1.6-30% (v/v), and the samples were prepared by compression – cold pressing. Characterization included examination of the influence of particle size and morphology on the conductivity and percolation threshold of the composites using a variety of testing techniques: SEM, TGA, DSC, particle size distribution and conductivity measurements. The thermal analysis of the prepared composites showed the improvement of the thermal characteristics of the composites. This was due to the presence of the metallic fillers which are very good thermal conductors, hence accumulating the emitted heat during TGA measurements primary to lignocellulosic matrix. On the other hand, there is no difference in the response with different metallic fillers and particles with different morphologies. Glass transition temperature is improved by 20 ºC for all the composites.
Effect of alumina particle size on aging in Al2O3/Al-Cu-Mg composite materials.