Brochure: A Synopsis of Analytical Procedures - Timcal

www.timcal.comAnalytical procedures forENSACO and SUPER P Conductive Carbon BlackThe specific electricalresistance of thecarbon blackA carbon black sample of 0.5 g is placedbetween two copper electrodes in a non-conductivemould and pressed by means of apneumatic driven piston at pressures of 50kg/cm 2 and 100 kg/cm 2 respectively. Theelectrical resistance and the thickness of thecarbon black are measured at the two pressuresand the electrical resistivity is calculatedand expressed in ohm.cm.Reference:- TIMCAL methodElectrical resistivity measurementsof compoundsIn a Brabander roller mixer of 50 ml theHDPE is melted at 160 °C for 2 minutes at arotating speed of 60 rpm. Then the carbon isadded and the compounding continues for 5minutes. The compound plate(s) is(are)pressed at 180 °C for 2 minutes applying aforce of 200 kN.The measurement needs 5 samples of polymer/carbonblack compounds with thicknessof about 2 mm, having a minimum length of4 cm and a width of +/- 2cm. Each sample ismeasured by using a 4 point contacts methodin a sample holder respecting ASTM D4496-87. The electrical resistivity of the compoundis the average of the 5 resistivities calculatedfrom the electrical resistances of the samplesand their geometrical shapes. If the resistanceof the sample or the contact resistances arelarger than +/- 10 10 ohm the measurement isperformed with an electrometer with respectto ASTM D257-93. In this case the sampleshould have a minimum diameter of 6.5 cm.Reference:- TIMCAL method8