以氮化硼(BN)和氮化铝(AlN)为导热填料,采用溶液超声剥离法将BN和AlN分散在聚酰胺6(PA6)中,再与聚偏氟乙烯(PVDF)熔融共混,制备了具有双逾渗结构的PVDF/(PA6/BN/AlN)导热复合材料,研究了导电填料BN/AlN在两相中的选择性分布以及BN/AlN填充量对复合材料导热性能和介电性能的影响。结果表明,BN/AlN选择性地分布在PA6中,随着BN/AlN填充量的增加,复合材料热导率升高,有利于提高复合材料的吸热和散热能力。BN/AlN填充量为5%(wt,质量分数,下同)时,复合材料的热导率为0.564W/(m·K),与纯PVDF/PA6复合材料相比,热导率提高了164.8%。BN/AlN的加入有利于提高PVDF/PA6复合材料的介电性能,在BN/AlN填充量为5%、频率为100Hz条件下,PVDF/(PA6/BN/AlN)复合材料介电常数达到11923,是纯PVDF/PA6介电常数的917倍。
Using boron nitride (BN) and aluminum nitride (AlN) as thermally conductive fillers,BN and AlN are dispersed in polyamide 6(PA6) by solution ultrasonic stripping,and then melt blended with polyvinylidene fluoride (PVDF),PVDF/(PA6/BN/AlN) thermal conductive composites with double percolation structure was prepared.The effect of BN/AlN loading on the thermal conductivity and dielectric properties of PVDF/PA6 composite were investigated.The results showed that BN/AlN selectively distributed in the PA6 phase.With the increase of BN/AlN loading,the thermal conductivity of the composite increases,which are beneficial to improve the heat absorption and heat dissipation ability of the composite.When the BN/AlN loading is 5wt%,the thermal conductivity of the composite is 0.564W/(m·K),and the thermal conductivity is increased by 164.8% compared with the pure PVDF/PA6 composite.The addition of BN/AlN is also beneficial to improve the dielectric properties of PVDF/PA6 composite.When BN/AlN is 5wt% and the frequency is 100Hz,the dielectric constant value is 11923,which was 917 times that of pure PA6/PVDF composite.
[1] Song S H,Park K H,Kim B H,et al.Enhanced thermal conductivity of epoxy-graphene composites by using non-oxidized graphene flakes with non-covalent functionalization[J].Advanced Materials,2013,25(5):732-737.
[2] I-Hsiang Tseng,Chang Jen-Chi,Huang Shih-Liang,et al.Enhanced thermal conductivity and dimensional stability of flexible polyimide nanocomposite film by addition of functionalized graphene oxide[J].Polymer International,2013,62(5):827-835.
[3] Wang Y,Tao Z Q,Chen J S.High thermal conductive insulation composite materials[C].Materials Science Forum,2016.
[4] 周文英,王子君,董丽娜,等.聚合物/BN导热复合材料研究进展[J].合成树脂及塑料,2015,32(2):80-84.
[5] Ruh R,Donaldson K Y,Hasselman D P H.Thermal conductivity of boron carbide-boron nitride composites[J].Journal of the American Ceramic Society,2010,75(10):2887-2890.
[6] Chen J,Huang X,Sun B,et al.Vertically aligned and interconnected boron nitride nanosheets for advanced flexible nanocomposite thermal interface materials[J].ACS Applied Materials & Interfaces,2017,9(36):30909-30917.
[7] Lee H M,Bharathi K,Kim D K,et al.Processing and characterization of aluminum nitride ceramics for high thermal conductivity[J].Advanced Engineering Materials,2014,16(6):655-669.
[8] Im H,Kim J.The effect of Al2O3 doped multi-walled carbon nanotubes on the thermal conductivity of Al2O3/epoxy terminated poly (dimethylsiloxane) composites[J].Carbon,2011,49(11):3503-3511.
[9] Zhou T,Wang X,Liu X,et al.Improved thermal conductivity of epoxy composites using a hybrid multi-walled carbon nanotube/micro-SiC filler[J].Carbon,2010,48(4):1171-1176.
[10] 张娜.双连续相导热复合材料的制备工艺研究[D].北京:北京化工大学,2015.
[11] Monemian S,Jafari S H,Khonakdar H A,et al.MWNT-filled PC/ABS blends:correlation of morphology with rheological and electrical response[J].Journal of Applied Polymer Science,2013,130(2):739-748.
[12] Poyekar A V,Bhattacharyya A R,Panwar A S,et al.Evolution of phase morphology and ‘network-like’ structure of multiwall carbon nanotubes in binary polymer blends during melt-mixing[J].Polymer Engineering & Science,2015,55(2):429-442.
[13] Liu Z,Philippe Maréchal,Robert Jérôme.Melting and crystallization of poly (vinylidene fluoride) blended with polyamide 6[J].Polymer,1997,38(20):5149-5153.
[14] Li Y,Shi Y,Cai F,et al.Graphene sheets segregated by barium titanate for polyvinylidene fluoride composites with high dielectric constant and ultralow loss tangent[J].Composites Part A:Applied Science & Manufacturing,2015,78:318-326.
