Journal of South China University of Technology(Natural Science Edition) ›› 2021, Vol. 49 ›› Issue (12): 16-22.doi: 10.12141/j.issn.1000-565X.200778

Special Issue: 2021年化学化工

• Chemistry & Chemical Engineering • Previous Articles     Next Articles

Effect Of Side Group Substitution On The Properties Of Cardo-type Polyimides Containing Hydroxyl Groups

LIU Shumei1 CHEN Jiajun1 WU Yancheng1 ZHAO Jianqing1,2   

  1. 1. College of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, Guangdong, China;
    2. Guangdong Key Lab of High Property & Functional Polymer Materials, Guanzhou 510640, Guangdong, China
  • Received:2020-12-18 Revised:2021-04-25 Online:2021-12-25 Published:2021-12-01
  • Contact: 刘述梅(1968-),女,教授,主要从事高分子合成与材料高性能化、功能化改性研究。 E-mail:liusm@scut.edu.cn
  • About author:刘述梅(1968-),女,教授,主要从事高分子合成与材料高性能化、功能化改性研究。
  • Supported by:
    Supported by the Key Basic Research and Applied Basic Research Program of Guangdong Province(2019B1515120073) and the Key-Area Research Development Program of Guangdong Province(2019B010940001)

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Abstract: The cardo-type polyimides containing hydroxyl groups (PI-OH) were synthesized with one-step chemical imidzation method by taking hydroxyl-containing fluorene diamine and 44′-(44′-Isopropylidenediphenoxy) diphthalic anhydride as substrates. Then, cardo-type polyimides with low polarity and bulky size propionyloxy side groups (PI-OA)/tert-butyldimethylsiloxy side groups (PI-OSi) were prepared by acyl oxidation or silyl ether reaction of side hydroxyl groups. The effects of side group substitution on the solubility, optical and dielectric properties, etc. of PI-OH were systematically investigated. The results show  that the polarity and size of side groups greatly impacts the performances of PI films. Compared with PI-OH, PI-OA and PI-OSi show better solubility, higher transmittances and lower dielectric constants. Both can dissolve in low polar solvents such as dichloromethane or acetone. Their transmittances at 450nm can reach 86.7% and 85.2%, their dielectric constants are as low as 2.75 and 2.63 (1MHz). PI-OA and PI-OSi exhibit lower glass transition temperature and higher thermal expansion coefficients due to the introduction of low polarity and bulky size substituent groups.

Key words: side group substitution, cardo-type polyimides containing hydroxyl groups, acyl oxidation, silyl ether reaction, solubility, transmittance, dielectric property

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