MAGNETORHEOLOGICAL URETHANE ELASTOMERS ACTIVATED BY MAGNETIC FIELD

摘要

Urethane and urea-urethane segmental elastomers(EPU 1,1 and EPU 1,25)were synthesized and selected properties of them were compared with those of polyurethane gels(PU 80/20 and PU 70/30)prepared by mixing of commercial products(Table 1).Various amounts of ferromagnetic particles(carbonyl iron)were added to elastomers preparing in this way magnetorheological urethane elastomers(MRE).They were cured in magnetic field and column arrangement of Fe particles has been obtained.The effects of conditions of MRE preparation on their structures were evaluated using transmission microscopy and SEM and significant dependence on the amount of Fe particles in a composite was found(Fig.1,2).For Fe amount higher than 11.5 vol.% the structure looks like a net.Magnetic properties of MRE obtained were investigated by VSM method in directions parallel and perpendicular to magnetic particles arrangement(Fig.5).The changes of properties depend on the composite structure and the power of external magnetic field applied,causing an increase in shear modulus(Fig.3,4,6).