Study On The Preparation And Properties Of Highly Filled PPS-based Magnetic Composites

With the demand increases of plastic magnets in the field of high temperature,more and more researchers focus their attentions on the development of plastic magnet made by PPS.In this paper,quenched NdFeB and strontium ferrites were chosen to mix with PPS by twin screw extruder for preparing highly filled PPS-based magnetic composites.The flowing,mechanical and magnetic properties were measured by melt flow indexer,electric testing machine,and permanent magnetic measuring instrument.The microstructures of the composites were observed by scanning electron microscopy?SEM?.The influences of filler contents,coupling agents,lubricants and toughening agents on the PPS-based magnetic composites were also studied.For the PPS/NdFeB composites,it is found in the sdudy that when the particle size of NdFeB powder is 13.88?m,the magnetic properties and thermal stability are quite good.The maximum filling amounts of the magnetic powder can be 89 wt%.Coupling agents can effectively improve the flowability of PPS/NdFeB composites.When the addition amount of the coupling agent KH550 is 0.3 wt%,the maximum filling amount of NdFe B magnetic powder is 89 wt%.In this case,the composites have the good processing properties.The density,the melt flow rate and?BH?max of the composite are 4.89 g/cm³,170 g/10min and 25.33 kJ/cm³respectively.For the PPS/SrFe₁₂O₁₉9 composites,it is shown in the sdudy that the magnetic properties of composites increase with the increase of the filler contents.The coupling agents and lubricants obviously improve the flow ability of the composites.The maximum filling amount of strontium ferrite powder is 90 wt%with the addition of 0.6 wt%KH550 and 4 wt%mixed lubricant in the experiments.The melt flow rate of the composite reaches 83 g/10min.The toughness of the material can be increased by two times with the addition of 3 wt%POE elastomeric toughening agent,about 7.5 kJ/m².Injection rate also has a significant impact on the magnetic composite materials.The maximum energy product of the composite sample reaches15.6 kJ/cm³ when using the proper process.It is discovered that the application temperature and keeping time have significant impacts on the thermal stability of PPS and PPS/NdFeB composites.In the study,when the application temperature is over 250^oC,the thermal stability of PPS/NdFeB composites will deteriorate significantly.Thus,in order to obtain better performances,it should be possible to reduce the processing temperatures with the permission of processing.The using temperature should be lower than 250^oC to extend their lifetime in the application process.