Study On The Toughening Modification Of PPS-Based Bonded Strontium Ferrite Magnetic Composites

Along with the increasing application demand of plastic magnetic products in the high temperature field,the plastic magnetic products based on PPS get the favor of more and more researchers.Based on PPS matrix,strontium ferrite as filter,using extrusion method,a kind of PPS based magnetic composite material was prepared with high magnetic powder filter.Melt index instrument,electronic universal testing machine,thermo gravimetric analyzer and scanning electron microscopy(SEM)were used to characterize the flow properties,mechanical properties,thermal properties,microstructure of PPS composite correspondingly.The influences of different systems of toughening agent such as elastomeric,fiber,inorganic nanoparticles,etc.were analyzed.TPU effectively improves the IS of Sr-ferrite/PPS/TPU ternary composite though it partly decomposes at the high processing temperature of PPS.By controlling the additions of TPU,composites with improved toughness can be achieved.The IS is achieved to be 5.77 kJ/m2 increased by around 51.44% when the content of TPU reaches to 11 wt %.The SEM patterns reveal the good compatibility between TPU and PPS.The action mechanism of TPU on PPS is proposed and discussed based on the experimental results.The hard segments of TPU decompose during the melt blending and generate the isocyanate groups(-CNO),which reacts with the end group(-SH)in PPS.Due to the graft of PPS molecular chains by TPU,the IS and thermal stability are improved.This is different from the conventional toughening mechanism by the conformation of elastomers and the suppression of microcracks propagation.The toughness of Sr-ferrite/PPS/CF ternary composite is obviously improved with the increased content of carbon fiber in the toughening system of carbon fiber.After cleaning surface By HF acid,different surface oxidation treatment increased the surface activity and functional groups of carbon fiber.Experiments showed that with the increase of oxidation time,the surface activity of carbon fiber was enhanced,but also damaged the intrinsic carbon fiber strength.The IS is achieved to be 7.08 kJ/m2 increased by around 103.4% when the carbon fiber is oxidized by dilute nitric acid after 24 hours.The precipitated silica with good lipophilicity was used for toughening PPS matrix,and its average particle size was 36~61nm accounting for about 92.8%.Experiments show that the toughness of Sr-ferrite/PPS/silica ternary composite was improved with carbon black coupling by KH550.When the content of white carbon black content is 3wt%.The IS is achieved to be 4.25 kJ/m2 increased by around 9.3%.The toughening effect of white carbon black is relatively significant,but it didn't sacrifice mobility and heat resistance of the composites.