Lee Yun Seon, Yu Jaesang, Shim Sang Eun, Yang Cheol-Min
Institute of Advanced Composite Materials, Korea Institute of Science and Technology (KIST), 92 Chudong-ro, Wanju-gun, Jeonbuk 55324, Korea.
Department of Chemical Engineering, Inha University, 100 Inha-ro, Nam-gu, Incheon 22212, Korea.
Polymers (Basel). 2020 Apr 14;12(4):909. doi: 10.3390/polym12040909.
In this study, we investigated the synergistic effects of thermally conductive hybrid carbonaceous fillers of mesophase pitch-based carbon fibers (MPCFs) and reduced graphene oxides (rGOs) on the thermal conductivity of polymer matrix composites. Micro-sized MPCFs with different lengths (50 μm, 200 μm, and 6 mm) and nano-sized rGOs were used as the thermally conductive fillers used for the preparation of the heat-dissipation polymer composites. For all MPCF fillers with a different length, the thermal conductivity values of the MPCF/epoxy composites were proportional to the MPCF length and loading amount (0-50 wt%) of MPCFs. For an MPCF:rGO weight ratio of 49:1 (total loading amount of 50 wt%), the thermal conductivity values of MPCF-rGO/epoxy composites loaded with MPCFs of 50 μm, 200 μm, and 6 mm increased from 5.56 to 7.98 W/mK (approximately 44% increase), from 7.36 to 9.80 W/mK (approximately 33% increase), and from 11.53 to 12.58 W/mK (approximately 9% increase) compared to the MPCF/epoxy composites, respectively, indicating the synergistic effect on the thermal conductivity enhancement. The rGOs in the MPCF-rGO/epoxy composites acted as thermal bridges between neighboring MPCFs, resulting in the formation of effective heat transfer pathways. In contrast, the MPCF-rGO/epoxy composites with MPCF:rGO weight ratios of 48:2 and 47:3 decreased the synergistic effect more significantly compared to rGO content of 1 wt%, which is associated with the agglomeration of rGO nanoparticles. The synergistic effect was inversely proportional to the MPCF length. A theoretical approach, the modified Mori-Tanaka model, was used to estimate the thermal conductivity values of the MPCF-rGO/epoxy composites, which were in agreement with the experimentally measured values for MPCF-rGO/epoxy composites loaded with short MPCF lengths of 50 and 200 μm.
在本研究中，我们研究了中间相沥青基碳纤维（MPCFs）和还原氧化石墨烯（rGOs）的导热混合碳质填料对聚合物基复合材料热导率的协同效应。使用不同长度（50μm、200μm和6mm）的微米级MPCFs和纳米级rGOs作为用于制备散热聚合物复合材料的导热填料。对于所有不同长度的MPCF填料，MPCF/环氧树脂复合材料的热导率值与MPCF的长度和负载量（0 - 50 wt%）成正比。对于MPCF:rGO重量比为49:1（总负载量为50 wt%）的情况，与MPCF/环氧树脂复合材料相比，负载50μm、200μm和6mm MPCFs的MPCF-rGO/环氧树脂复合材料的热导率值分别从5.56增加到7.98 W/mK（增加约44%）、从7.36增加到9.80 W/mK（增加约33%）以及从11.53增加到12.58 W/mK（增加约9%），表明对热导率增强有协同效应。MPCF-rGO/环氧树脂复合材料中的rGOs充当相邻MPCFs之间的热桥，导致形成有效的热传递路径。相比之下，MPCF:rGO重量比为48:2和47:3的MPCF-rGO/环氧树脂复合材料与1 wt%的rGO含量相比，协同效应下降得更显著，这与rGO纳米颗粒的团聚有关。协同效应与MPCF长度成反比。采用一种理论方法，即修正的Mori-Tanaka模型，来估计MPCF-rGO/环氧树脂复合材料的热导率值，该值与负载50和200μm短MPCF长度的MPCF-rGO/环氧树脂复合材料的实验测量值一致。
