Preparation And Characterization Of PVA-co-PE Composite Nanofibers Supporting High Thermal Conductivity Particles

Nowadays,the rapid development of miniaturized and intelligent electronic components has imposed higher requirements on its own thermal performance.Finding more efficient and smaller thermal materials has become a new research hotspot.Melt-extrusion and phase separation method is a simple and convenient method for mass-producing micro-and nano-fibers by extrusion polymer masterbatch with a melt extruder.It is very suitable for heat conductive fillers.The research on the microstructure and thermal conductivity of high-heat-conducting particle nanofibers is helpful to accelerate the application of thermally conductive polymer nanofibers in the fields of electronics and thermal conduction.In this paper combines thermal conductive nanoparticles with PVA-co-PE nanofibers to prepare thermally conductive nanofibers which have thermally conductivity,insulation performance,transparency,and good mechanical property.The main contents and results include the following three parts:(1)Preparing AlN/PVA-co-PE composite powders by the method of melt blending.And preparing AlN/PVA-co-PE nanocomposite fibers by blending CAB with the composite powders in the twin-screw spinning machine.The basic structure and properties of composite nanofiber membranes were characterized by SEM,TEM,XRD,TG,mechanical properties test and thermal conductivity test.The results show that the diameter of composite fibers increases with the increasing of AlN nanopowders,and the surface becomes uneven.The AlN powders are uniformly distributed in the fibers in a small-scale agglomeration manner.The intermixing between the components has a certain influence on the crystallinity of the fiber.The thermal stability of the composite fiber improved by doping AlN,and the thermal conductivity improves too.But the tensile properties deteriorate,and the transparent of composite fiber with the expoxy resin become worse.(2)Preparing BN/PVA-co-PE composite powders by the method of melt blending.And preparing BN/PVA-co-PE nanocomposite fibers by blending CAB with the composite powders in the twin-screw spinning machine.The composites membrane was prepared using a spray coating metod.The basic structure and properties of composite nanofiber membranes were characterized by SEM,TEM,XRD,TG,mechanical properties test and thermal conductivity test.The results show that the composite fibers become thicker,and the surface becomes uneven.The BN powders are distributed in the inner and the surface of the fibers in a small-scale agglomeration and monolithic embedding manner.The intermixing between the components has a certain influence on the crystallinity of the fiber.The thermal stability of the composite fiber improved by doping BN.When the doping rate is smaller than 5wt%,the mechanical properties are enhanced,and worse when the weight is greater than 5wt%.At the same time,the transmittance of the compound film with the epoxy resin is also seriously reduced.(3)Preparing MWNTs/PVA-co-PE and BN/MWNTs/PVA-co-PE composite membranes by mixing MWNTs and BN wit PVA-co-PE.The basic structure and properties of composite nanofiber membranes were characterized by SEM,TEM,XRD,TG,mechanical properties test and thermal conductivity test.The results show that the composite fibers become thicker.The and the heatconducting particles were distributed along the fiber orientation in the fibers.The addition of MWNTs increased the thermal conductivity and thermal stability of the composite fibers,enhanced the breaking strength,and reduced the elongation.But the doping of MWNTs and BN makes a serious reduction in the mechanical strength and the thermal stability.When doped with 8wt%MWNTs+20wt%BN,the thermal conductivity reaches 0.6236 W/m·K.The thermal conductivity of the film is increased by 180% which is significantly improved.