现代纺织技术 ›› 2023, Vol. 31 ›› Issue (5): 30-40.

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二氧化硅气凝胶填充蔺草纤维复合材料的制备及其热隐身性能

  

  1. 1.浙江理工大学材料科学与工程学院,杭州310018; 2.杭州万事利丝绸数码印花有限公司,杭州310020
  • 出版日期:2023-09-10 网络出版日期:2023-09-20
  • 作者简介:陈黎唤(1995—),男,浙江台州人,硕士研究生,主要从事天然纤维制备方面的研究。
  • 基金资助:
    浙江省重点研发计划(2121069-J);浙江省清洁染整技术研究重点实验室开放基金项目(QJRZ2110);浙江省基础公益研究计划(LGC22E030006)

Silica aerogel-filled Juncus effusus fiber composites and their thermal stealth properties

  1. 1. School of Materials Science & Engineering, Zhejiang Sci-Tech University, Hangzhou 310018, China; 2. Hangzhou WENSLI Silk Digital Printing Co., Ltd., Hangzhou 310020, China
  • Published:2023-09-10 Online:2023-09-20

摘要: 天然蔺草纤维(JEFs)具有良好的物化性能和独特的中空多髓结构,其被编织为草席、榻榻米等家居产品使用。然而,蔺草纤维木质素含量较高导致柔韧性较差,并且其官能团种类较少导致功能欠缺,限制了它的进一步应用。采用亚氯酸钠和冰醋酸混合溶液对蔺草纤维进行预处理,得到脱木质素纤维(CTFs),随后通过溶胶-凝胶法在蔺草纤维内部生长二氧化硅气凝胶,制得二氧化硅气凝胶/蔺草纤维 (SiO2/CTFs)。进一步通过真空浸渍的方式制得聚乙二醇/二氧化硅气凝胶/蔺草纤维复合材料(PEG/SiO2/CTFs)。对纤维复合材料的形貌、结构、物化性能进行了表征,并探究了纤维复合材料的隔热和热隐身性能。结果表明:由于二氧化气凝胶具有较好的隔热性能,SiO2/CTFs材料的隔热性能进一步提高,导热系数低至0.039 W/(m·K),隔热能力比CTFs提高了71.7%,比表面积最大可达270.01 m2/g,比CTFs提高了37.8倍,由于PEG的出色的储热能力以及吸收红外热辐射的功能,故PEG/SiO2/CTFs具有明显的红外热隐身特性。研究结果为蔺草纤维应用提供了新的技术路径。

关键词: 蔺草纤维, 溶胶-凝胶法, 二氧化硅气凝胶, 聚乙二醇, 红外热隐身

Abstract: Juncus effusus fibers (JEFs) have good physical chemical properties and a unique hollow, multi-pith structure. They have been woven into straw mats, tatami mats and other household products. They have also been presented as "national gifts" to friends abroad. However, the lack of functionality has limited their wide application. Chemical modification and nanoparticle filling are important technical means to further expand the use of JEFs. In this paper, the modified fibers (CTFs) were obtained by pretreating JEFs with a mixture of sodium chlorite and glacial acetic acid. Subsequently, the silica aerogels were filled with silica aerogels inside the CTFs by the sol-gel method to produce silica aerogels/CTFs (SiO2/CTFs). Finally, by vacuum impregnation, we produced polyethylene glycol/silica aerogel/ CTFs composites (PEG/SiO2/CTFs). The morphology, structure and physical chemical properties of the three samples of CTFs, SiO2/CTFs and PEG/SiO2/CTFs were characterized and compared by scanning electron microscopy, infrared spectroscopy, X-ray diffractometer, thermogravimetric analyzer, specific surface area tester, infrared thermography and thermal conductivity meter. It is found through the electron microscope images that the silica aerogels are fully filled inside the CTFs, and the fibers and aerogels are well bonded, while the SiO2/CTFs made after freeze-drying have lower porosity. The infrared spectra show the appearance of Si-O-Si bonds and Si-C bonds in the SiO2/CTFs material, proving the feasibility of the sol-gel method to introduce the silica aerogel inside the fibers. The main weight loss peak of the thermogravimetric test SiO2/CTFs was between 300°C and 400 °C, indicating improved thermal stability compared to CTFs. The thermal conductivity of SiO2/CTFs was measured by the thermal conductivity meter as 0.039 W/(m·K), and the thermal insulation capacity was improved by 71.7% compared with CTFs. The specific surface area of SiO2/CTFs was tested up to 270.01 m²/g, 37.8 times higher than that of CTFs. The pore size distribution map shows that SiO2/CTFs have more mesopores than CTFs, with the freeze-dried SiO2/CTFs having the smallest pore size. It is consistent with the results observed in the electron micrographs. Infrared thermography showsthat the SiO2/CTFs are significantly more insulating than the CTFs. In addition, the electron micrographs show high (>90%) and uniform loading of PEG inside the SiO2/CTFs. Differential scanning calorimetry tests show that the melt peak of PEG/SiO2/CTFs shift toward higher temperatures, indicating a stronger heat storage capacity. Thermogravimetric tests show the improved thermal stability of PEG/SiO2/CTFs. Infrared thermography shows that PEG/SiO2/CTFs have obvious infrared thermal stealth properties. The preparation method of SiO2/CTFs and PEG/SiO2/CTFs is simple and effective, providing scientific data for functionalized modification and new application fields for JEFs.

Key words: Juncus effusus fiber, sol-gel method, silica aerogel, thermal insulation, infrared thermal stealth

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