Acta Chimica Sinica ›› 2024, Vol. 82 ›› Issue (2): 126-131.DOI: 10.6023/A23080387 Previous Articles     Next Articles

Special Issue: 庆祝《化学学报》创刊90周年合辑 有机氟化学合集

Article

三氟氯乙烯与甲基异丙烯基醚的光诱导共聚反应

易敬霖, 陈茂*()   

  1. 复旦大学 高分子科学系 聚合物分子工程国家重点实验室 上海 200433
  • 投稿日期:2023-08-21 发布日期:2023-10-05
  • 作者简介:
    庆祝《化学学报》创刊90周年.
  • 基金资助:
    国家自然科学基金(22171051); 聚合物分子工程国家重点实验室的资助

Photo-Induced Copolymerization of Chlorotrifluoroethylene and Methyl Isopropenyl Ether

Jinglin Yi, Mao Chen()   

  1. Department of Macromolecular Science, State Key Laboratory of Molecular Engineering of Polymers, Fudan University, Shanghai 200433
  • Received:2023-08-21 Published:2023-10-05
  • Contact: E-mail: chenmao@fudan.edu.cn
  • About author:
    Dedicated to the 90th anniversary of Acta Chimica Sinica.
  • Supported by:
    National Natural Science Foundation of China(22171051); State Key Laboratory of Molecular Engineering of Polymers

Fluoropolymers exhibit unique properties, such as outstanding thermal stability and chemical inertness, ultralow surface energy, and have found broad applications in lots of areas. Many fluoropolymers show high crystallinity and low solubility, restricting their practical usage through melting and solution processing. To address such issues, copolymerization of fluoroalkenes and comonomers have been developed to prepare fluorinated copolymers that retain fluoroalkyl characteristics and good processibility, bringing many important commercial products, for example, copolymers of chlorotrifluoroethylene (CTFE) and vinyl ethers. However, such copolymers could possess low glass transition temperature (Tg), which is a key property to influence the applicable scope. In this work, we report copolymerization of CTFE and methyl isopropenyl ether (MIE) for the first time, which have enabled the synthesis of novel fluorinated copolymers under LED (light emitting diode) light irradiation conditions by merging an organic thermally activated delayed fluorescence catalyst and a redox active organic amine via a redox-relay catalysis. In comparison to conventional free radical (co)polymerization of fluoroalkenes, this method not only provides main-chain fluoropolymers of readily tunable molecular weights as evidenced by gel permeation chromatography (GPC) and multi-angle light scattering detection coupled with GPC (GPC-MALS), but also allows smooth transformation of fluoroalkene feedstock at ambient pressure using common Schlenk glassware without needing high-pressure metallic vessels. Although the obtained CTFE-MIE copolymers exhibited less controlled molecular weight distributions (MWDs) and limited chain-end fidelity as confirmed by chain-extension polymerization and GPC analysis, the chain-growth process presents first-order kinetics as validated by monitoring the monomer consumption, and follows alternating copolymerization as supported by the variation of degrees of polymerization (DPs) of both vinyl compounds along the light irradiation time, presenting improved chain-growth control as compared to conventional free radical transformation. Notably, as analyzed by differential scanning calorimetry (DSC), in contrast to copolymers of CTFE and ethyl vinyl ether (EVE), the CTFE-MIE copolymers with similar molecular weights exhibit clearly improved Tg of about 50 ℃ via simply introducing methyl substituents on the polymer backbone. Given the broad interests in fluoropolymers and established applications of fluoroalkene-vinyl ether copolymers, we believe that this work should be informative to the rational design of novel fluoropolymers and attractive for material engineering with improved thermal stability.

Key words: fluoropolymer, copolymer, photopolymerization, reversible deactivation radical polymerization, chlorotrifluoroethylene