Owais Mohammad, Shiverskii Aleksei, Sulimov Artem, Ostrizhiniy Dmitriy, Popov Yuri, Mahato Biltu, Abaimov Sergey G
Center for Design, Manufacturing and Materials, Skolkovo Institute of Science and Technology, 121205 Moscow, Russia.
Center for Hydrocarbon Recovery, Skolkovo Institute of Science and Technology, 121205 Moscow, Russia.
Polymers (Basel). 2022 Aug 15;14(16):3316. doi: 10.3390/polym14163316.
In this study, three-dimensional (3D) polyvinyl alcohol (PVA)/aligned boron nitride (BN) aerogel framework nanocomposites with high performance were fabricated by a facile strategy. The boron nitride powder was initially hydrolyzed and dispersed with a chemically crosslinked plasticizer, diethyl glycol (DEG), in the PVA polymer system. The boron nitride and DEG/PVA suspensions were then mixed well with different stoichiometric ratios to attain BN/PVA nanocomposites. Scanning electron microscopy revealed that BN platelets were well dispersed and successfully aligned/oriented in one direction in the PVA matrix by using a vacuum-assisted filtration technique. The formed BN/PVA aerogel cake composite showed excellent in-plane and out-of-plane thermal conductivities of 0.76 W/mK and 0.61 W/mK with a ratio of BN/PVA of (2:1) in comparison with 0.15 W/mK for the pure PVA matrix. These high thermal conductivities of BN aerogel could be attributed to the unidirectional orientation of boron nitride nanoplatelets with the post-two days vacuum drying of the specimens at elevated temperatures. This aerogel composite is unique of its kind and displayed such high thermal conductivity of the BN/PVA framework without impregnation by any external polymer. Moreover, the composites also presented good wettability results with water and displayed high electrical resistivity of ~10 Ω cm. These nanocomposites thus, with such exceptional characteristics, have a wide range of potential uses in packaging and electronics for thermal management applications.
在本研究中，通过一种简便的策略制备了具有高性能的三维（3D）聚乙烯醇（PVA）/取向氮化硼（BN）气凝胶框架纳米复合材料。首先将氮化硼粉末在PVA聚合物体系中与化学交联增塑剂二甘醇（DEG）进行水解和分散。然后将氮化硼和DEG/PVA悬浮液以不同的化学计量比充分混合，以获得BN/PVA纳米复合材料。扫描电子显微镜显示，通过真空辅助过滤技术，BN片层在PVA基体中良好分散并成功地在一个方向上排列/取向。所形成的BN/PVA气凝胶饼状复合材料在BN/PVA比例为（2:1）时，面内和面外热导率分别达到0.76 W/mK和0.61 W/mK，相比之下，纯PVA基体的热导率为0.15 W/mK。BN气凝胶的这些高导热率可归因于氮化硼纳米片的单向取向以及样品在高温下进行两天的真空干燥。这种气凝胶复合材料独具特色，在未被任何外部聚合物浸渍的情况下，BN/PVA框架展现出如此高的热导率。此外，该复合材料对水还表现出良好的润湿性，并且具有~10 Ω cm的高电阻率。因此，这些具有卓越特性的纳米复合材料在用于热管理应用的包装和电子领域具有广泛的潜在用途。
