Rheological properties of PDMS-based magnetoelastomers during curing
Sprache des Vortragstitels:
International Congress on Rheology
Sprache des Tagungstitel:
Magnetoelastomers are elastomeric-based materials whose mechanical properties and shape can be modified by means of external magnetic fields. This is accomplished by adding magnetic metallic particles to an elastomer matrix, either in an isotropic or in an anisotropic arrangement. Due to these specific features, such composites are usually called ?smart materials?. These materials have increasingly been used as mechanical actuators or in applications involving controlled mechanical damping. The latter application is possible because the viscoelastic properties of the composite can be quickly adjusted by varying the magnetic field direction and strength.
The final mechanical properties and intended applications of magnetoelastomers have a strong dependence on the particle distribution and their arrangement within the elastomeric matrix. The required movement of the particles inside the matrix depends obviously to a great extent on the viscosity of the system before it cures completely. In order to properly control these parameters, knowledge about the rheological properties of the composite system is therefore essential.
This work deals with the preparation and rheological characterization of isotropic magnetoelastomers based on a commercial polydimethylsiloxane (PDMS) matrix filled with carbonyl iron particles. Various shapes and surface functionalities of the particles are used with the purpose of trying to achieve customised interactions at the matrix-particle interface. The initial approach consists on studying the crosslinking kinetics and its dependence on the particle properties by means of time-resolved rheological measurements. This information will be important for further experimental work, with the aim of preparing specimens with controlled anisotropy of the filler particles. Preliminary results of the dynamic mechanical properties of the first isotropic specimens will be also briefly discussed.