Chemical sensors based on polymer composites

Developing materials which could be applied as sensors has been attempted. The materials were electrically conductive polymer composites, which matrices were: HDPE, PS, PP, HDPE/PS and HDPE/PP blend. The filler was carbon black of particle size 10-110 nm. Electrical conductivity, mechanical strength, Vicat softening temperature and melt theology were investigated. The lowest percolation threshold was achieved at 2 wt.% of carbon black, which resulted in electrical resistance of 10(7) Omega m. Along with the filler volume the Vicat softening temperature increased at every polymer matrix for a few centigrades. At the highest filler content the tensile Young modulus of composites was four times higher, whereas elongation at break decreased substantially if compared to the net polymers. Melt viscosity increased with carbon black content, making composites hardly processable at high filler loadings. (c) 2005 Elsevier B.V. All rights reserved.