Research On The Preparation And Properties Of Magnetic Polyurethane Composites

Magnetic polymer composites are obtained by dispersing magnetic nanoparticles in polymeric matrix.The properties of magnetic composites depend on the polymeric matrix,nanoparticles and interaction of them.Polyurethane with flexibility and wear resistance is an excellent material for preparing magnetic composite materials.Composite materials have excellent magnetic properties because the magnetic fillers are added in polyurethane.But the nano magnetic material has small size and magnetic moment force resulting in poor dispersion of magnetic filler in the polymer.Therefore,in this paper,the inexpensive and easily obtained materials used to combine Fe₃O₄ nanoparticles to prepare magnetic particles.In this paper,we did a few studies,as follows:First,chitosan was used to wrap nano-Fe₃O₄ particles to prepare chitosan/Fe₃O₄nanoparticles（CS/Fe₃O₄）.Second,the surface of CS/Fe₃O₄ was modified by isophorone diisocyanate to obtain modified magnetic microsphere（mCS/Fe₃O₄）.The structure and properties of the modified magnetic microspheres were characterized by FTIR,SEM and XRD.A series of PU-mCS/Fe₃O₄ composites with different filler contents were prepared by in-situ polymerization of mCS/Fe₃O₄ into polyurethane.The experimental results show that the appropriate amount of mCS/Fe₃O₄ magnetic microspheres can enhance the hydrophilicity,mechanical properties,thermal stability,excellent magnetic properties,antibacterial properties and good biocompatibility of PU-mCS/Fe₃O₄ composites.We also studied the simultaneous introduction of nano-Fe₃O₄ and reduced graphene oxide in waterborne polyurethane to enhance the magnetic properties and electrical conductivity of the composite.First,attapulgite-Fe₃O₄ magnetic filler（ATP-Fe₃O₄）was prepared by chemical precipitation method.Subsequently,graphite oxide（GO）was prepared through Hummer method,then reduced graphite oxide（RGO）was prepared through GO reduced by chitosan.Finally,a series of WPU-RGO/ATP-Fe₃O₄/CS composites were prepared by introduced RGO/ATP-Fe₃O₄/CS to polyurethane.The structure and properties were characterized by SEM,FTIR,XRD,VSM,TGA,conductivity test and tensile test.The experimental results indicate that thermal stability,tensile strength of nanocomposites were improved with the increasing of the content of RGO/ATP-Fe₃O₄/CS.Meanwhile,WPU-RGO/ATP-Fe₃O₄/CS composites have good conductivity and magnetic property.