化工进展 ›› 2021, Vol. 40 ›› Issue (7): 3862-3869.DOI: 10.16085/j.issn.1000-6613.2020-1586

• 材料科学与技术 • 上一篇    下一篇

微波化学反应用聚四氟乙烯容器的透波性能

魏聪1(), 尚小标1,3,4(), 张富程1, 刘美红1, 白永珍1, 李广超1, 肖利平1, 翟迪1, 陈君若2   

  1. 1.昆明理工大学机电工程学院,云南 昆明 650500
    2.昆明理工大学城市学院,云南 昆明 650051
    3.非常规冶金教育部重点实验室,云南 昆明 650093
    4.微波能工程应用及装备技术国家地方联合工程实验室,云南 昆明 650093
  • 收稿日期:2020-08-10 修回日期:2020-12-31 出版日期:2021-07-06 发布日期:2021-07-19
  • 通讯作者: 尚小标
  • 作者简介:魏聪(1992—),男,硕士研究生,研究方向为微波能工程应用技术。E-mail:W18987274033@163.com
  • 基金资助:
    国家自然科学基金(51764052);云南省科技厅重大专项(2018ZE008);云南省人才培养项目(KKSY201601045)

Transmission properties of polytetrafluoroethylene container for microwave chemical reaction

WEI Cong1(), SHANG Xiaobiao1,3,4(), ZHANG Fucheng1, LIU Meihong1, BAI Yongzhen1, LI Guangchao1, XIAO Liping1, Di ZHAI1, CHEN Junruo2   

  1. 1.Faculty of Mechanical and Electrical Engineering, Kunming University of Science and Technology, Kunming 650500, Yunnan, China
    2.City College, Kunming University of Science and Technology, Kunming 650051, Yunnan, China
    3.Key Laboratory of Unconventional Metallurgy of Ministry of Education, Kunming 650093, Yunnan, China
    4.National Local Joint Laboratory of Engineering Application of Microwave Energy and Equipment Technology, Kunming 650093, Yunnan, China
  • Received:2020-08-10 Revised:2020-12-31 Online:2021-07-06 Published:2021-07-19
  • Contact: SHANG Xiaobiao

摘要:

因聚四氟乙烯(PTFE)具有较低的复介电常数,其作为透波材料而被广泛用作微波化学反应用容器。透波材料的介电特性和透波性能对微波化学反应的速率和效果具有重要影响。本研究首先利用谐振腔微扰法测量了PTFE在23~250℃范围内的复介电常数,并分析了该材料介电属性的温度特性;其次,基于电磁波传输原理,计算了该材料受到不同因素影响下的功率透过系数(T2),并对该材料的透波性能进行了分析。研究表明,随着温度的增加,PTFE的介电常数逐渐减小,损耗正切逐渐增大,但是二者变化幅度较小;在水平(TM)极化中存在一个布儒斯特角θB,当微波以该角度入射时会发生全透射现象;TM极化下的T2随着入射角的增大先增大后减小,垂直(TE)极化下的T2随着入射角的增加而减小,TM极化下的整体透波性能要优于TE极化;随着容器壁厚的增加,透波性能波动变化,存在极大值和极小值;在相同容器壁厚范围内(0~0.1m),2450MHz频率下对应高透波性能的厚度值要多于915MHz。研究还表明,微波入射角度较小时,PTFE的T2始终保持在0.87~0.99之间,透波性能较好。最后给出了微波以不同频率入射时PTFE的优选壁厚以供实际应用过程中进行参考。

关键词: 微波化学, 聚四氟乙烯, 容器, 介电特性, 透波性能

Abstract:

The polytetrafluoroethylene (PTFE) is widely used as a container for microwave chemical reactions because it is transmitting material with relatively low complex dielectric constant. The dielectric properties and transmitting properties of transmitting materials have an important influence on the rate and effect of microwave chemical reactions. In this article, firstly, the complex dielectric constant of PTFE in the range of 23—250℃ was measured by the resonant cavity perturbation method and the temperature characteristic of the dielectric properties of the material was analyzed. Secondly, based on the principle of electromagnetic wave transmission, the power transmission coefficient (T2) of the material affected by different factors was calculated and the transmission performance of the material were analyzed. The research showed that with the increase of temperature, the dielectric constant of PTFE gradually decreased and the loss tangent gradually increased, but the magnitude of the two changes were small. There was a Brewster angle in the transverse magnetic field (TM). When microwaves were incident at this angle of incidence, total transmission occurred. The T2 in the TM polarization mode firstly increased and then decreased with the increase of the incident angle. The T2 in the transverse electric field (TE) decreased with the increase of the incident angle. The overall transmission performance in TM polarization mode was better than TE polarization. As the wall thickness of the container increased, the transmission performance fluctuated and there were maximum and minimum values. Within the same container wall thickness range (0—0.1m), the wall thickness range corresponding to high transmission performance at 2450MHz frequency was more than 915MHz. The research also showed that when the incident angle of microwave was small, the T2 of PTFE always remained between 0.87 and 0.99 and the transmission performance was better. Finally, this article also gave the preferred wall thickness of PTFE for reference in practical applications when microwaves were incident at different frequencies.

Key words: microwave chemistry, polytetrafluoroethylene, container, dielectric property, transmission property

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