Papers by Keyword: Electrically Conductive Composite

Abstract: The paper presents the development results of "smart" pressure-sensitive fibre-cement compositematerials as well as thin-film coating sensors designed to detect disruptions of the base materialstructure. Basic material characteristics of fine-grained and coarse-grained cement matrices wereacquired during the research. The benefits and influence of conductive inorganic components,metallic components in the form of iron fillings and steel wires, and last but not least carbon-basednon-metallic fibrous reinforcement, have been verified. Thin-film epoxy resin coatings were enrichedwith amorphous carbon black, multi-walled carbon nanotubes (MWCNT) and natural micronizedgraphite. The article closely describes the measurement of electrical and electro-mechanical(piezoresistive) properties of conductive fibre-cement composites and thin-film organic coatings in anon-loaded state, during static loading and especially during dynamic ballistic and shock tests on thefall tower. Specific electrical characteristics and the course of change in electric conductivity wasexpressed as electrical resistivity (the real component of the impedance).The performed experiments confirmed excellent electrical conductivity of dense steel-fibrereinforced composites and graphite-doped hybrid fibre reinforced concrete. The coatings showedsignificant and permanent changes in impedance in the order of tens of ohms. The newly developedfibre composites and coating layers change the impedance during destructive and non-destructivedynamic loading tests. The impedance changed not only during failure of the matrix, but also in thecase of indirect impact. Moreover, carbon reinforced concrete with incorporated graphite showedsome piezoresistive properties. These detection materials were intended to be part of a ballistic-resistant monitoring system.

Abstract: Polymer materials manufactured of natural resources have been characterized. Polylactid acid (PLA) was used as a matrix for composites filled with carbonaceous fillers of different geometry (carbon black and carbon nanofibres). Polymer strands made of electrically conductive PLA composites have a promising potential as materials for fabrication of sensors sensitive to strain, temperature or organic solvents. For better understanding of the correlation between processing parameters of PLA composites and their sensing ability the melt characteristics have been evaluated using a capillary rheometer and Rheotens melt strength tester. Strain sensing was monitored under three point bending by means of electrical conductivity measurements.

Abstract: Stiff and tough conductive composites were manufactured using carbon black compounded with high and low density polyethylene, as well as linear low density polyethylene. A low percolation threshold value for the composites was achieved at 2 wt% carbon black. The impact strengths of the composites incorporating low density and linear low density polyethylene were found to be almost 16 and 26 times greater, respectively, than that of high density polyethylene composites. On the other hand, the modulus of high density polyethylene filled with carbon black was 2 times as high as low and linear low density polyethylene-based composites. Tensile modulus increased with the content of carbon black, however the impact strength of the composites decreased.