Supercritical CO2 fluid: synthesis and application of new RAFT reagent
Controlled Free Radical Polymerization of DFHMA in Surpercritical Carbon Dioxide: Synthesis and Application of a Novel RAFT Agent
Feng-Xian1,2, Wang Ming-Xi1,2, Wang-Kuan1,2, Chen Jian-Gang 1,2,*, Liu Zhao-Tie 1,2, Liu Zhong-Wen 1,2 , Jiang Jinqiang1,2, Hao Zhengping2,3
Herein a novel fluorinated RAFT agent of S,S-di-pentaflourobenzyl trithiocarbonate (DPFBTTC) was synthesized, and its structure was characterized by FTIR 1H NMR and 13C NMR. Poly(dodecafluoroheptyl methacrylate) (PDFHMA) was synthesized via RAFT polymerization method using DPFBTTC as the RAFT agent and AIBN as the initiator in scCO2. Kinetic curves were obtained by using a set of high pressure in situ FTIR monitoring system, and the controllability of DPFBTTC to the polymerization of DFHMA was explored. The results showed that the solubility as well as the controllability of the fluorinated RAFT agent, DPFBTTC, was better than that of dibenzyl trithiocarbonate (DBTTC) in scCO2 system. Meanwhile, highly stable fluorinated end groups would appear in the polymeric product as DPFBTTC was introduced to the polymerization of DFHMA in scCO2. The thermal stability and transparency of resulted polymer are expected to be improved so as to meet the special application of such kind of poly meric materials.
Fluorine-containing (meth)acrylates have the dual characteristics of common (meth)acrylate monomers and fluorine-containing monomers. The polymerization and conversion of such monomers into fluorine-containing polymers belongs to branched fluorine-containing polymerization. Fluoropolymers have excellent hydrophobicity, stain resistance, low friction coefficient and excellent optical properties . In terms of high-performance alternative materials, functional film materials, medical materials, optical devices and optical fibers, scCO2 It is recognized as an environmentally friendly green medium. Trying to use scCO2 to replace conventional organic solvents in polymer synthesis will help reduce pollution, protect the environment, and save energy. Studies have also shown that fluoromonomers and some (high fluorine content) fluoropolymers can be dissolved in In scCO2 , this brings bright prospects for preparing some fluoropolymers in scCO2 system through homogeneous solution polymerization. Reversible addition-fragmentation chain transfer polymerization (RAFT polymerization) is a typical controllable/living radical polymerization method . Polymerization, RAFT polymerization has become an important method for polymer molecular design and synthesis due to its wide range of monomers, mild polymerization conditions, and effective control of the ground structure . The synthesis of polymers with complex topological structures, such as branching, hyperbranching, and tandem, has been widely studied and applied. However, fluorine-containing RAFT reagents suitable for the polymerization of fluorine-containing monomers, especially high fluorine-containing acrylic monomers, are rarely reported. This is a study on the synthesis of fluoropolymer materials in scCO2 systems under restricted conditions. And application.In order to explore and realize that the RAFT polymerization method in the scCO2 system can be used to control the preparation of fluoropolymers that meet the needs of specific applications (such as the polymerization process and product structure controllable, no hydroxyl end groups in the generated molecules, etc.), here is a design and synthesis The new fluorine-containing RAFT reagent DPFBTTC is connected to the polymerization of DFHMA in the alternate scCO2 system. The polymerization process is monitored by high-pressure in-situ near infrared spectroscopy. Based on the results of polymerization kinetics, the controllability of DPFBTTC on DFHMA polymerization is explored and verified . This study is expected to be the basis for further research and application of the fluoropolymer material synthesis in the scCO2 system.