A preliminary investigation of conductive immiscible polymer blends as sensor materials

Abstract

This paper discusses the feasibility of the application of conductive immiscible polymer blends as sensor materials for detection of organic liquid solvents. Immiscible polymer blends of polypropylene (PP). nylon 6 (Ny6) and carbon black (CB) have been used to produce a series of electrically conductive b e n t s by a capillary rheometer process. In these immiscible blends, PP serves as a semi-crystalline matrix and Ny6 as the semi-crystalline dispersed phase. The enhancement of conductivity in these blends is due to the attraction of CB to Ny6 and localization of CB particles at the PP/Ny6 interface, giving rise to conductive networks. The dc electrical resistivity of extruded filaments, produced at different shear levels, is found to be sensitive to various organic liquid solvents. The shear rate at which the filaments are produced has an important effect on the PP/Ny6/CB filament's sensitivity. The compositions studied were close to the double-percolation structure believed to perform best as sensor materials. In addition, it seems that the PP/Ny6 interface plays a major role in the sensing process. Liquid contact/drymg cycling of the filaments indicates stabilization of the sensitivity change making the sensing process reversible.

Polymer composites as sensing materials for liquid organic solvents – preliminary results

“…The filaments of thermoplastic polyurethane-carbon black compunds displayed an increase in resistance upon exposure to various alcohols (methanol, ethanol, and 1-propanol) [4]. The same effect, combined with excellent reproducibility and recovery behavior has been shown for extruded PP/thermoplastic polyurethane blends containing CB [7]. A decreasing resistance upon exposure to methanol, ethanol and 1-propanol was examined for electrically conductive blends, containing two immiscible polymers (ethylene-co-vinyl acetate as a matrix and copolyamide as a dispersed phase) and polyaniline [8].…”

“…A principle of operation these devices is based on a change of their electrical properties upon exposure to a studied sample. In a sensor technology both the intrisically conducting polymers (their conductivity can be changed by doping) and composites (electrically insulating polymer matrix with a conductive filler) are applied [1][2][3][4][5][6][7][8][9][10][11].…”

PTC effect and structure of polymer composites based on polyethylene/polyoxymethylene blend filled with dispersed iron

“…The study of the PTC effect attracted much attention in recent years because of the perspectives of applications, namely for temperature sensors, materials for production of thermistors, self-regulating heaters, etc [8][9][10][11][12][13]. The nature of the PTC effect is not definitively clear, but it is generally accepted that the sharp increase of resistance with increase of temperature is caused by the thermal expansion of the thermoplastic matrix near the melting temperature.…”

Transparent Conductive Films Fabricated from Polythiophene Nanofibers Composited with Conventional Polymers

“…There are several different types of conductive nanofillers, including carbon nanotubes [18][19][20][21][22][23][24][28][29][30][31][32][33][34][35][36], carbon fibers [26], metal particles [25], and conductive polymers [37,38]. Our aim in the present work was to solve the problems associated with the P3HT nanofiber mat as a transparent, conductive film by using the nanocomposite technique.…”