Wang Jiahao, Kasuya Keitaro, Koga Hirotaka, Nogi Masaya, Uetani Kojiro
Graduate School of Engineering, Osaka University, Mihogaoka 8-1, Ibaraki-shi, Osaka 567-0047, Japan.
The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki-shi, Osaka 567-0047, Japan.
Nanomaterials (Basel). 2021 Mar 8;11(3):658. doi: 10.3390/nano11030658.
Chitin, a natural polysaccharide polymer, forms highly crystalline nanofibers and is expected to have sophisticated engineering applications. In particular, for development of next-generation heat-transfer and heat-insulating materials, analysis of the thermal conductivity is important, but the thermal conductivity properties of chitin nanofiber materials have not been reported. The thermal conductivity properties of chitin nanofiber materials are difficult to elucidate without excluding the effect of adsorbed water and analyzing the influence of surface amino groups. In this study, we aimed to accurately evaluate the thermal conductivity properties of chitin nanofiber films by changing the content of surface amino groups and measuring the thermal diffusivity under dry conditions. Chitin and deacetylated-chitin nanofiber films with surface deacetylation of 5.8% and 25.1% showed in-plane thermal conductivity of 0.82 and 0.73 W/mK, respectively. Taking into account that the films had similar crystalline structures and almost the same moisture contents, the difference in the thermal conductivity was concluded to only depend on the amino group content on the fiber surfaces. Our methodology for measuring the thermal diffusivity under conditioned humidity will pave the way for more accurate analysis of the thermal conductivity performance of hydrophilic materials.
几丁质是一种天然多糖聚合物，可形成高度结晶的纳米纤维，有望用于复杂的工程应用。特别是在开发下一代传热和隔热材料方面，热导率分析很重要，但几丁质纳米纤维材料的热导率特性尚未见报道。如果不排除吸附水的影响并分析表面氨基的影响，就很难阐明几丁质纳米纤维材料的热导率特性。在本研究中，我们旨在通过改变表面氨基含量并在干燥条件下测量热扩散率，来准确评估几丁质纳米纤维膜的热导率特性。表面脱乙酰度为5.8%和25.1%的几丁质和脱乙酰几丁质纳米纤维膜的面内热导率分别为0.82和0.73W/mK。考虑到这些膜具有相似的晶体结构且水分含量几乎相同，得出热导率的差异仅取决于纤维表面的氨基含量。我们在特定湿度条件下测量热扩散率的方法将为更准确地分析亲水性材料的热导率性能铺平道路。
