Testing of Piezoresistive Polyurethane-Fe 3 O 4 Composites

Author： Carlson W. Bartkowski S. Schulze W. Pilgrim S.

ISSN： 0015-0193

Source： Ferroelectrics, Vol.331, Iss.1, 2006-01, pp. : 83-88

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Abstract

The piezoresistance of Fe 3 O 4 particles encapsulated in polyurethane forming a composite material were studied for hydrostatic and uniaxial response. Electrical and mechanical properties were examined in composite disks with volume percents of Fe 3 O 4 loading between 35 and 54%. Uniaxial and hydrostatic loading tests were conducted for electrical resistance under mechanical stress. Data obtained for the uniaxially loaded samples indicate that resistance changes of 5 to 6 orders of magnitude can be tailored in polyurethane composites. Under hydrostatic loading testing indicates that resistance changes of 2 orders of magnitude can be obtained. Mounting the piezoresistors in a rigid epoxy improves the hydrostatic response of the samples allowing resistance change of up to 3 orders of magnitude. Further tests indicate a change of almost 5 orders of magnitude are possible when highly compliant lateral air gaps are incorporated into the sample.