STRAIN SENSORS BASED ON GRAPHITE FILLERS

In this research, producing a particulate conductive composite is being investigated. The composites are made of ethylene-vinyl acetate (EVA) and polyvinyl choloride (PVC) as matrix and graphite as filler. There are two different procedures applied: dissolving the polymer matrix in a suitable solvent and then add the filler to the solution, which does not work out for PVC because phase separation takes place between the melt mixing of the matrix and filler. The solvents used were toluene for EVA and THF for PVC. The composites were prepared in different volume fractions. After having the composites prepared they were compression moulded into the shape of dumbbells when two extreme sides were covered with a conductive coating. Electrical resistance of the samples before and during applying the strain was measured. Then, gauge factor (strain sensitivity factor) for each sample was calculated and finally the sample with higher gauge factor was chosen. Saloumeh Moshfegh and Nadereh Golshan Ebrahimi*