Unsaturated Polyester Conductive Composites And Performance Study

Composites based on expanded graphite (EG) and unsaturated polyester resin (UPR) were prepared. Curing condition and casting processing technique of the composites were investigated. Electrical resistivity measurements at room temperature reveal that the value of threshold is only 2% by weight, which is much lower than that of conventional conducting composites. The volume electrical resistivity of EG/UPR composite at temperature reaches 106 Ω m when graphite content is 3.5% by weight.The mechanical properties of EG/UPR composites change abruptly in the vicinity of percolation threshold. When the EG content is lower than the threshold, EG particles show some reinforcing effect to the matrix; the mechanical properties decrease slightly when EG content is higher than the threshold. The thermal degradation behavior of the composites was studied by means of TGA, it shows that the thermal stability of composites is less higher than that of pure UPR. The SEM microphotographs turn out that EG particles are dispersed homogeneously in the matrix to form continuous conducting network when graphite content is 2.5% by weight. Glass fiber reinforced EG/UPR composites were also prepared and exhibited good comprehensive properties.