Abstract:

The peapod-like composite phase change microfibers, with both polyvinyal butyral (PVB) matrix blended with aluminum oxide (Al₂O₃) nanoparticles and with n-pentadecane encapsulated, are successfully prepared by microfluidic technology. Effects of Al₂O₃ content on the microstructures, phase change properties and thermal conductive properties of the as-prepared composite phase change microfibers are systematically investigated. The results show that n-pentadecane is effectively encapsulated into the independent micro-compartments by the dense surface of composite phase change microfibers, and the encapsulation ratio is about 30%. The addition of Al₂O₃ nanoparticles into the PVB matrix has no obvious effect on the peapod-like microstructure and phase change enthalpies of composite phase change microfibers, while significantly enhances their thermal conductive properties. Under the simulated solar irradiation, the surface temperature of the composite phase change microfibers containing 10% Al₂O₃ nanoparticles increases faster than that of phase change microfibers without Al₂O₃ nanoparticles, and the melting time of the former are shorten by 25%. The results provide valuable guidances for fabricating phase change microfibers with controllable structure, satisfactory and stability thermal conductive properties, as well as efficient and fast thermal regulation properties.

Key words: microfluidics, peapod-like structure, phase change, fibers, alumina, nanoparticles, thermal conductive properties

摘要：

利用微流控技术成功制备了聚乙烯醇缩丁醛（PVB）基材中共混氧化铝（Al₂O₃）纳米颗粒，其内部包封正十五烷的豆荚结构复合相变纤维。系统考察了Al₂O₃的含量对复合相变纤维的微观结构、相变性能和导热性能的影响规律。研究结果表明，复合相变纤维的致密表面可将正十五烷良好地包封于其内部的独立腔室内，包封率约为30%。在PVB基材中添加Al₂O₃纳米颗粒对复合相变纤维的豆荚结构和相变焓均无明显影响，但可显著提高相变纤维的导热性能。在模拟太阳光照射下，添加10% Al₂O₃纳米颗粒的复合相变纤维的表面温度比不含Al₂O₃纳米颗粒的相变纤维的表面温度升高更快，前者的熔融时间比后者缩短了25%。研究结果将为制备结构可控、具有良好、稳定导热性能和高效、快速调温性能的相变纤维提供重要的实验参考和指导。

关键词: 微流体学, 豆荚结构, 相变, 纤维, 氧化铝, 纳米粒子, 导热性能