Crystal Transition Behavior and Thermal Properties of Thermal-Energy-Storage Copolymer Materials with an n-Behenyl Side-Chain
Crystal Transition Behavior and Thermal Properties of Thermal-Energy-Storage Copolymer Materials with an n-Behenyl Side-Chain
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DOI：
10.3390/polym11091512
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发表时间：
2019-07
期刊：
影响因子：
5
通讯作者：
Y. Mao;Jin Gong;Meifang Zhu;Hiroshi Ito
中科院分区：
文献类型：
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作者：
Y. Mao;Jin Gong;Meifang Zhu;Hiroshi Ito
本文采用悬浮聚合法合成了MC(BEA-co-MMA)共聚物微胶囊。BEA的侧链N-苯基是高度结晶性的，在BEA-co-MMA共聚物结构中起侧链的作用。高度结晶的n-苯基侧链提供了BEA-co-MMA共聚物的储热能力。为了研究BEA-co-MMA共聚物的热性能与晶体结构之间的关系，讨论了单体配比、温度变化和变化率以及合成方法对BEA-co-MMA共聚物热性能的影响。单体配比对聚合物的晶化行为和热性能有较大影响。差示扫描量热法结果表明，当单体比为3：1时，MC(BEA-co-MMA)3的平均相变热ΔH最大，为105.1 J·g-1。结果表明，n-苯基侧链形成了较为完善的晶区，保证了共聚物的高储能能力。DSC和SAXS结果表明，BEA的用量对共聚物的储热能力和晶体间距有很大影响，但对晶片的影响不大。结果表明，在BEA-co-MMA共聚物的n-苯基侧链晶体结构中，MMA单元的作用类似于缺陷。因此，较低的MMA含量，即较高的BEA含量，有助于提高BEA-co-MMA共聚物的结晶度，提供更好的储能能力和温度调节性能。采用光诱导聚合法制备了与微胶囊成分相同的St(BEA-co-MMA)共聚物片，考察了合成方法的效果。结果表明，合成方法主要影响共聚物的化学组成，而对n-苯基侧链的晶体堆积影响不大。
In this paper, we synthesized MC(BeA-co-MMA) copolymer microcapsules through suspension polymerization. The pendent n-behenyl group of BeA is highly crystalline, and it acts as the side-chain in the structure of BeA-co-MMA copolymer. The highly crystalline n-behenyl side-chain provides BeA-co-MMA copolymer thermal-energy-storage capacity. In order to investigate the correlation between the thermal properties and crystal structure of the BeA-co-MMA copolymer, the effects of monomer ratio, temperature changing and the changing rate, as well as synthesis method were discussed. The monomer ratio influenced crystal transition behavior and thermal properties greatly. The DSC results proved that when the monomer ratio of BeA and MMA was 3:1, MC(BeA-co-MMA)3 showed the highest average phase change enthalpy ΔH (105.1 J·g–1). It indicated that the n-behenyl side-chain formed a relatively perfect crystal region, which ensured a high energy storage capacity of the copolymer. All the DSC and SAXS results proved that the amount of BeA had a strong effect on the thermal-energy-storage capacity of the copolymer and the long spacing of crystals, but barely on the crystal lamella. It was found that MMA units worked like defects in the n-behenyl side-chain crystal structure of the BeA-co-MMA copolymer. Therefore, a lower fraction of MMA, that is, a higher fraction of BeA, contributed to a higher crystallinity of the BeA-co-MMA copolymer, providing a better energy storage capacity and thermoregulation property. ST(BeA-co-MMA) copolymer sheets with the same ingredients as microcapsules were also prepared through light-induced polymerization aiming at clarifying the effect of the synthesis method. The results proved that the synthesis method mainly influenced the copolymer chemical component, but lightly on the crystal packing of the n-behenyl side-chain.