Fabrication and thermally conductive properties of functionalized SiC nanowires/liquid crystal epoxy composites
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摘要: 高导热聚合物基复合材料在电子设备领域具有重要的应用价值。本论文基于“本征-填充”协同作用,以合成的本征型导热液晶环氧树脂为基体,以液晶环氧功能化改性碳化硅纳米线(SiCNWs-LCE)为高导热填料,采用液相共混法制得低填充且高导热SiCNWs-LCE/液晶环氧复合材料。分析了合成液晶环氧树脂的化学结构和结晶行为,以及功能化改性SiCNWs的微观形貌、化学结构和热稳定性等,深入研究了SiCNWs-LCE含量对SiCNWs-LCE/液晶环氧复合材料导热性能和热稳定性的影响规律。结果表明:采用硅烷偶联剂和液晶环氧功能化改性后的SiCNWs具有良好的分散性;“本征-填充”的协同作用使SiCNWs-LCE/液晶环氧复合材料具有良好的导热性能;复合材料的导热性能随着SiCNWs-LCE含量的增加而提高。与纯的液晶环氧树脂相比较,SiCNWs-LCE/液晶环氧复合材料热导率由0.33 W/(m·K)增加至0.72 W/(m·K),提升了118%。Abstract: Highly thermally-conductive polymer-based composites have important application value in the field of electronic equipment. Based on the “intrinsic-filled” synergistic effect, the liquid crystal epoxy functionalized SiC nanowires (SiCNWs-LCE)/liquid crystal epoxy composites with low filling amount and high thermal conductivity were prepared by the liquid phase blending method, using the synthesized intrinsic thermally-conductive liquid crystal epoxy as matrix and SiCNWs-LCE as highly thermally-conductive fillers. The chemical structures, crystallization behaviors of the liquid crystal epoxy and microstructures, chemical structures and thermal stability of the functionalized SiCNWs were analyzed. The influences of SiCNWs-LCE content on the thermal conductivity and thermal stability of the SiCNWs-LCE/liquid crystal epoxy composites were investigated in detail. The results show that the SiCNWs functionalized by silane coupling agent and liquid crystal epoxy have good dispersibility. The “intrinsic-filled” synergistic effect endows the SiCNWs-LCE/liquid crystal epoxy composite with excellent thermal conduc-tive properties. The thermal conductivity of SiCNWs-LCE/liquid crystal epoxy composites increases with the SiCNWs-LCE content. Compared with the pure liquid crystal epoxy resin, the SiCNWs-LCE/liquid crystal epoxy composites exhibit an increased thermal conductivity from 0.33 W/(m·K) to 0.72 W/(m·K) with an improvement of 118%.
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图 1 对苯二亚甲基-二-(4-氨基-3-甲基苯酚)缩水甘油醚(DGETAM) (a)和碳化硅纳米线-液晶环氧树脂(SiCNWs-LCE) (b)的合成机制
Figure 1. Synthetic mechanism of diglycidyl ether of terephthalylidene-bis(4-amino-3-methylphenol) (DGETAM) (a) and liquid crystal epoxy functionalized SiC nanowires (SiCNWs-LCE) (b)
DMSO—Dimethylsulfoxide; KH550—γ-Aminopropyl triethoxysilane; EtOH—Ethyl alcohol
表 1 SiCNWs、SiCNWs-OH、SiCNWs-KH550和SiCNWs-LCE的元素含量
Table 1. Element contents of SiCNWs, SiCNWs-OH, SiCNWs-KH550 and SiCNWs-LCE
Nanomaterials C/at% N/at% O/at% Si/at% SiCNWs 13.01 0.07 1.11 85.81 SiCNWs-OH 29.78 0.18 4.18 65.86 SiCNWs-KH550 34.06 0.64 5.76 59.54 SiCNWs-LCE 34.28 1.04 8.07 57.69 -
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