Moradi Sasan, Román Frida, Calventus Yolanda, Hutchinson John M
Departament de Màquines i Motors Tèrmics, ESEIAAT, Universitat Politècnica de Catalunya, C/Colom 11, 08222 Terrassa, Spain.
Polymers (Basel). 2021 Mar 20;13(6):955. doi: 10.3390/polym13060955.
This work demonstrates that the application of even moderate pressures during cure can result in a remarkable enhancement of the thermal conductivity of composites of epoxy and boron nitride (BN). Two systems have been used: epoxy-thiol and epoxy-diamine composites, filled with BN particles of different sizes and types: 2, 30 and 180 μm platelets and 120 μm agglomerates. Using measurements of density and thermal conductivity, samples cured under pressures of 175 kPa and 2 MPa are compared with the same compositions cured at ambient pressure. The thermal conductivity increases for all samples cured under pressure, but the mechanism responsible depends on the composite system: For epoxy-diamine composites, the increase results principally from a reduction in the void content; for the epoxy-thiol system with BN platelets, the increase results from an improved matrix-particle interface; for the epoxy-thiol system with BN agglomerates, which has a thermal conductivity greater than 10 W/mK at 44.7 vol.% filler content, the agglomerates are deformed to give a significantly increased area of contact. These results indicate that curing under pressure is an effective means of achieving high conductivity in epoxy-BN composites.
这项工作表明，即使在固化过程中施加适度压力，也能显著提高环氧树脂与氮化硼（BN）复合材料的热导率。使用了两种体系：环氧-硫醇和环氧-二胺复合材料，填充有不同尺寸和类型的BN颗粒：2μm、30μm和180μm的片状颗粒以及120μm的团聚颗粒。通过密度和热导率测量，将在175 kPa和2 MPa压力下固化的样品与在常压下固化的相同成分样品进行比较。所有在压力下固化的样品的热导率均有所提高，但具体机制取决于复合材料体系：对于环氧-二胺复合材料，热导率的增加主要源于孔隙率的降低；对于含有BN片状颗粒的环氧-硫醇体系，热导率的增加源于基体-颗粒界面的改善；对于含有BN团聚颗粒的环氧-硫醇体系，在填料含量为44.7 vol.%时热导率大于10 W/mK，团聚颗粒发生变形，从而显著增加了接触面积。这些结果表明，压力固化是实现环氧-BN复合材料高电导率的有效方法。
