Magnetorheological characteristics of polymer coated magnetite particle composites with carbon nanotube nanohybrid

This study demonstrates physical adsorption of polymer coated nano-sized magnetite ([Fe.sub.3][O.sub.4]) onto multiwalled carbon nanotube (MWNT) surface. A new hybrid material was made following four consecutive procedures of co-precipitation, polymer coating, functionalized MWNT, and ultrasonication method. Polymer coated magnetite particle (MaPAm) composites with MWNT nanohybrid (MaPAmNT) were acquired. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) have been used to investigate their nanostructure and morphology, thus verifying that polyacrylamide coated magnetite particles were well adsorbed onto surface of the MWNT. From thermogravimetric analysis (TGA) data, we also confirmed compositions of the MaPAmNT. Magnetorheological (MR) properties of the MaPAmNT under an external magnetic field were investigated, exhibiting typical MR behavior of yield stress and shear stress. Index Terms--Magnetite, magnetorheological fluid, multiwalled carbon nanotube (MWNT), nanohybrid, polymer.