具有取向导热结构柔性相变复合材料的制备及导热性能

Preparation and thermal conductivity of flexible phase change composite materials with oriented thermal conductivity structure

  • 摘要: 为解决高分子基复合材料固有热导率较差这一问题,本研究采用简单高效、易工业化的开炼法在聚乙烯辛烯共弹性体(POE)基体中构建有序的取向结构,制备了一种具有优异综合性能的柔性相变复合材料。在开炼机的强剪切场作用下,石蜡(PW)和氮化硼(BN)在POE基体内部沿剪切场方向发生了定向取向排列,促进了导热通路的构建。当石墨烯纳米片(GNPs)和BN添加量分别为2wt%和25wt%时,PW-2wt%GNPs-25wt%BN/POE相变复合材料热导率(λ)从1.01W·m−1·K−1 (PW/POE)提高到2.59 W·m−1·K−1,提高了156%。并且PW-2wt%GNPs-25wt%BN/POE相变复合材料具有优异的拉伸强度(18.3MPa)和断裂伸长率(720%),在弯曲、折叠成复杂的形状后不会出现任何的破裂,在10次循环往复拉伸测试中具有良好的可回复性。此外,添加30wt%的PW能够赋予PW-2wt%GNPs-25wt%BN/POE一定的焓值44.1 J·g−1;当施加80 mW·cm−2的光照强度时,表面贴有PW-2wt%GNPs-25wt%BN/POE复合材料的瓶内温度高达54.3℃,较未添加GNPs的PW/POE提高了20℃,并且在光照条件下,PW-2wt%GNPs-25wt%BN/POE复合材料具有优异的光驱动可恢复性能,使其具有潜在的光热转换应用前景,在实际应用和工业化生产方面具备巨大潜力。

     

    Abstract: To address the issue of poor inherent thermal conductivity in polymer-based composites, this study employed a simple, efficient, and industrially viable kneading method to construct an ordered orientation structure within a polyolefin elastomer (POE) matrix, resulting in a flexible phase-change composite material with outstanding comprehensive performance. Under the strong shear field of the kneader, paraffin wax (PW) and boron nitride (BN) were oriented and arranged along the shear field direction within the POE matrix, facilitating the construction of thermal conduction pathways. When the graphene nanoplatelets (GNPs) and BN content were 2wt% and 25wt%, respectively, the thermal conductivity (λ) of the PW-2wt%GNPs-25wt%BN/POE phase-change composite material increased from 1.01 W·m−1·K−1 (PW/POE) to 2.59 W·m−1·K−1, representing a 156% enhancement. Moreover, the PW-2wt%GNPs-25wt%BN/POE phase-change composite material exhibited excellent tensile strength (18.3 MPa) and elongation at break (720%), with no signs of rupture after bending and folding into complex shapes, and demonstrated good recoverability in 10 cycles of tensile testing. Furthermore, adding 30wt% PW can endow PW-2wt%GNPs-25wt%BN/POE composite material with a certain enthalpy value of 44.1 J·g−1. Under an illumination intensity of 80 mW cm−2, the temperature inside a bottle coated with the PW-2wt%GNPs-25wt%BN/POE composite material reached 54.3°C, which was 20°C higher than that of the PW/POE without GNPs. Moreover, under illumination conditions, the PW-2wt%GNPs-25wt%BN/POE composite material exhibited excellent light-driven recoverable performance, suggesting its potential application in photothermal conversion, and thereby possessing significant potential for practical applications and industrial production.

     

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