Continuous fabrication of flexible, thermally conductive aluminum nitride/aramid nanofiber composite films
-
摘要: 设计制备柔性导热材料对柔性电子器件的热管理具有重要意义。本文基于溶剂剥离的芳纶纳米纤维和氮化铝(AlN)纳米颗粒，采用溶胶-凝胶-薄膜转换方法，连续制备了柔性导热的AlN/芳纶纳米纤维复合薄膜材料。其中，芳纶纳米纤维形成了三维连通的网络结构，提供力学支撑作用；AlN颗粒填充在该网络结构中，赋予复合材料良好的导热性能。结果显示，该复合材料的拉伸强度为65.5 MPa，断裂应变为12%，反复折叠300次后其拉伸强度和断裂应变保持率在90%以上，导热率为13.98 W·(m·K)−1。此外，该复合薄膜显示出良好的绝缘性能和耐热性能，体积电阻率为1.85×1015 Ω·cm、起始热分解温度为524℃。最后，演示该高性能的AlN/芳纶纳米纤维复合薄膜作为柔性基底材料，可用于冷却电子器件。Abstract: Designing and preparing flexible thermally conductive materials is important for thermal management of flexible electronic devices. Based on exfoliated aramid nanofiber and aluminum nitride (AlN) nanoparticle, flexible and thermally conductive composite films were fabricated by a sol-gel-film transformation approach. In the composite films, aramid nanofibers forms three-dimensional connective network for providing mechanical support. AlN nanoparticles are filled in the network of aramid nanofiber to impart the composite films with good thermal conduction performance. As a result, the tensile strength and strain at break are 65.5 MPa and 12%, respectively. After folding for 300 cycles, the composite films retain more than 90% of original tensile strength and strain at break. The thermal conductivity is up to 13.98 W·(m·K)−1. Moreover, the composite films show good electrically insulating property and thermal stability. The volume electrical resistivity and initial thermal decomposition temperature are 1.85×1015 Ω·cm and 524℃. Finally, we demonstrate that the high-performance AlN/aramid nanofiber composite films can be act as flexible substrate for cooling electronics.
-
Key words:
- aramid nanofiber /
- aluminum nitride /
- composite film /
- mechanical property /
- thermal conductivity
-
图 1 连续制备AlN/ANF-X薄膜的原材料、装置及成品
Figure 1. Raw materials, devices and finished products for continuous preparation of AlN/ANF-X films
图 2 冻干的AlN/ANF-X 40/60水凝胶内部的SEM图像
Figure 2. SEM images of lyophilized AlN/ANF-X 40/60 hydrogels inside (Circles identifies the AlN particles that adhered to ANF)
图 3 AlN/ANF-X 40/60复合薄膜横截面((a)、(b))和表面((e)、(f))及纯ANF薄膜横截面((c)、(d))和表面((g)、(h))的SEM图像
Figure 3. SEM images of AlN/ANF-X 40/60 composite films cross section ((a), (b))and surface ((e), (f)) and pure ANF films cross section ((c), (d)) and surface ((g), (h))
图 4 纯ANF薄膜和AlN/ANF-X 40/60复合薄膜的FTIR图谱
Figure 4. FTIR spectra of pure ANF films and AlN/ANF-X 40/60 composite films
图 5 纯ANF薄膜和AlN/ANF-X复合薄膜的拉伸应力-应变曲线(a)、复合薄膜折叠过程中的强度保持率和应变保持率(b)
Figure 5. Tensile stress-strain curves of pure ANF films and AlN/ANF-X composite films (a) and strength retention and strain retention during folding cycles (b)
图 6 纯ANF薄膜和AlN/ANF-X复合薄膜的体积电阻率
Figure 6. Volume resistivity of pure ANF film and AlN/ANF-X composite films
图 7 纯ANF薄膜和AlN/ANF-X 40/60复合膜的DSC曲线(a)以及AlN、ANF和AlN/ANF-X复合膜的TGA曲线(b)
Figure 7. DSC heating curves of pure ANF films and AlN/ANF-X 40/60 composite films(a), as well as TGA curves of AlN, ANF and AlN/ANF-X composite films(b)
图 9 薄膜在同一热源下的红外热像图
Figure 9. Infrared thermal image of the films under the same heat source ((1) Pure ANF; (2) AlN/ANF-X 20/80; (3) AlN/ANF-X 40/60)
图 8 纯ANF薄膜和AlN/ANF-X复合薄膜的导热系数
Figure 8. Thermal conductivities of pure ANF film and AlN/ANF-X composite films
图 10 AlN/ANF-X40/60复合薄膜的热导率与报道的AlN/聚合物复合材料比较
Figure 10. Thermal conductivity of the AlN/ANF-X 40/60 composite films compared with reported AlN/polymer composite materials (Mass fraction in the figure indicates the content of aluminum nitride particles)
图 12 贴有不同薄膜的LED芯片在15~165 s内工作时的红外热像图
Figure 12. Infrared thermal images of LED chips with different films working within 15-165 s
图 13 LED芯片的温度随工作时间的变化曲线
Figure 13. Temperature evolution curves of the LED chips with working time
表 1 氮化铝/芳纶纳米纤维三维网络(AlN/ANF-X)复合材料配比
Table 1. Proportion of aluminum nitride/aramid nanofiber 3D network (AlN/ANF-X) composites
Material AlN/wt% ANF/wt% Pure ANF 0 100 AlN/ANF-X 20/80 20 80 AlN/ANF-X 40/60 40 60 
下载: 导出CSV
表 2 纯ANF薄膜和AlN/ANF-X复合薄膜的热扩散系数、比热容、密度和导热系数
Table 2. Thermal diffusivity, specific heat capacity, density and thermal conductivity of pure ANF film and AlN/ANF-X composite films
Material α/(mm2·s−1) Cp/(J·(g·℃)−1) ρ/(g·cm−3) K/(W·(m·K)−1) ANF 5.320 1.249 1.131 7.51 AlN/ANF-X 20/80 7.516 1.069 1.114 8.94 AlN/ANF-X 40/60 11.725 1.196 0.997 13.98 Notes: K—Thermal conductivity; α—Thermal diffusivity coefficient; Cp—Heat capacity; ρ—Density.
下载: 导出CSV
-
[1] BALANDIN A A. Thermal properties of graphene and nanostructured carbon materials[J]. Nature Materials,2011,10(8):569-581. doi: 10.1038/nmat3064 [2] SONG W L, WANG W, VECA L M, et al. Polymer/carbon nanocomposites for enhanced thermal transport properties-carbon nanotubes versus graphene sheets as nanoscale fillers[J]. Journal of Materials Chemistry,2012,22(33):17133-17139. doi: 10.1039/c2jm32469e [3] CHEN J, HUANG X, SUN B, et al. Highly thermally conductive yet electrically insulating polymer/boron nitride nanosheets nanocomposite films for improved thermal management capability[J]. ACS Nano,2019,13(1):337-345. doi: 10.1021/acsnano.8b06290 [4] SLACK G A, TANZILLI R A, POHL R O, et al. The intrinsic thermal conductivity of AIN[J]. Journal of Physics & Chemistry of Solids,1987,48(7):641-647. [5] YU S, HING P, HU X. Thermal conductivity of polystyrene-aluminum nitride composite[J]. Composites Part A: Applied Science and Manufacturing,2002,33(2):289-292. doi: 10.1016/S1359-835X(01)00107-5 [6] CAO Y, IRWIN P C, YOUNSI K. The future of nanodielectrics in the electrical power industry[J]. IEEE Transactions on Dielectrics and Electrical Insulation,2004,11(5):797-807. doi: 10.1109/TDEI.2004.1349785 [7] CHOY C L. Thermal conductivity of polymers[J]. Polymer,1977,18(10):984-1004. doi: 10.1016/0032-3861(77)90002-7 [8] CHEN H, GINZBURG V V, YANG J, et al. Thermal conductivity of polymer-based composites: Fundamentals and applications[J]. Progress in Polymer Science,2016,59:41-85. doi: 10.1016/j.progpolymsci.2016.03.001 [9] WU G, WANG Y, WANG K, et al. The effect of modified AlN on the thermal conductivity, mechanical and thermal properties of AlN/polystyrene composites[J]. RSC Advances,2016,6(104):102542-102548. doi: 10.1039/C6RA22794E [10] KIM K, YOO M, AHN K, et al. Thermal and mechanical properties of AlN/BN-filled PVDF composite for solar cell backsheet application[J]. Ceramics International,2015,41(1):179-187. doi: 10.1016/j.ceramint.2014.08.056 [11] ZHANG K, PENG T, ZHANG Y H, et al. Highly thermal conductivity of CNF/AlN hybrid films for thermal management of flexible energy storage devices[J]. Carbohydrate Polymers,2019,213:228-235. doi: 10.1016/j.carbpol.2019.02.087 [12] GARCÍA J M, GARCÍA F C, SERNA F, et al. High-performance aromatic polyamides[J]. Progress in Polymer Science,2010,35(5):623-686. doi: 10.1016/j.progpolymsci.2009.09.002 [13] CHATZI E G, KOENIG J L. Morphology and structure of kevlar fibers: a review[J]. Polymer-Plastics Technology and Engineering,1987,26:229-270. doi: 10.1080/03602558708071938 [14] YANG M, CAO K, SUI L, et al. Dispersions of aramid nanofibers: A new nanoscale building block[J]. ACS Nano,2011,5(9):6945-6954. doi: 10.1021/nn2014003 [15] KUANG Q, ZHANG D, YU J C, et al. Toward record-high stiffness in polyurethane nanocomposites using aramid nanofibers[J]. The Journal of Physical Chemistry C,2015,119(49):27467-27477. doi: 10.1021/acs.jpcc.5b08856 [16] ZHU J, YANG M, EMRE A, et al. Branched aramid nanofibers[J]. Angewandte Chemie International Edition,2017,56(39):11744-11748. doi: 10.1002/anie.201703766 [17] TSAGAROPOULOS G, EISENBERG A. Dynamic mechanical study of the factors affecting the two glass transition behavior of filled polymers: Similarities and differences with random ionomers[J]. Macromolecules,1995,28(18):6067-6077. doi: 10.1021/ma00122a011 [18] PAN C, KOU K, WU G, et al. Fabrication and characterization of AlN/PTFE composites with low dielectric constant and high thermal stability for electronic packaging[J]. Journal of Materials Science: Materials in Electronics,2016,27(1):286-292. doi: 10.1007/s10854-015-3752-2 [19] CHEN P, KOU K C, ZHANG Y, et al. Enhanced through-plane thermal conductivity of PTFE composites with hybrid fillers of hexagonal boron nitride platelets and aluminum nitride particles[J]. Composites Part B: Engineering,2018,153:1-8. doi: 10.1016/j.compositesb.2018.07.019 [20] WU S Y, HUANG Y L, MA C C M, et al. Mechanical, thermal and electrical properties of aluminum nitride/polyetherimide composites[J]. Composites Part A: Applied Science and Manufacturing,2011,42(11):1573-1583. doi: 10.1016/j.compositesa.2011.06.009 [21] KIM K, KIM J. Magnetic aligned AlN/epoxy composite for thermal conductivity enhancement at low filler content[J]. Composites Part B: Engineering,2016,93:67-74. doi: 10.1016/j.compositesb.2016.02.052 [22] ZHANG T, WU X, LUO T. Polymer nanofibers with outstanding thermal conductivity and thermal stability: Fundamental linkage between molecular characteristics and macroscopic thermal properties[J]. The Journal of Physical Chemistry C,2014,118(36):21148-21159. doi: 10.1021/jp5051639 -
下载:
点击查看大图
计量
- 文章访问数: 1124
- HTML全文浏览量: 431
- PDF下载量: 104
- 被引次数: 0
