Controlled radical polymerization of fluorinated methacrylates in supercritical CO₂: Synthesis and application of a novel RAFT agent

Abstract

A novel fluorinated reversible addition‐fragmentation chain transfer agent, S,S‐di‐pentaflourobenzyl trithiocarbonate (DPFBTTC), was designed and synthesized. DPFBTTC and dibenzyl trithiocarbonate (DBTTC) were applied in the polymerization of dodecafluoroheptyl methacrylate (DFHMA), hexafluorobutyl methacrylate (HFBMA), and trifluoroethyl methacrylate (TFEMA) in scCO2. The polymerization processes were monitored using a high‐pressure in‐situ NIR, through which the polymerization kinetics was investigated and the controllability of DPFBTTC was evaluated. It is found that the controllability of DPFBTTC presented in the order of DFHMA > HFBMA > TFEMA, indicating that DPFBTTC may fit for the controlled polymerization of the highly fluorinated methacrylates. Moreover, the controllability of DPFBTTC is verified to be better than that of DBTTC, possibly resulting from the enhanced accessibility/miscibility of DPFBTTC to the fluorinated monomer used. We believe that the employment of DPFBTTC and the resulted introduction of stable pentafluorobenzyl end groups to the polymer are expected to distinctly improve performances of the polymer, and thus will meet the special application requirements. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 825–834

Insight into the Intermolecular Interaction and Free Radical Polymerizability of Methacrylates in Supercritical Carbon Dioxide

“…High pressure in situ FTIR/NIR experiments were performed using a PerkinElmer Spectrum 400 FTIR/NIR spectrometer supported by Spectrum Software (V 6.3.5, PerkinElmer, Bucks, UK) for data acquisition and processing. The spectrometer was intentionally modified either by replacing the standard sample accessories with a set of specially designed fiber sensor in attenuated total reflection (ATR) mode as was described in our previous work [21,29] or by integrating with a 50.0 mL stainless steel view cell to construct a high-pressure trans FTNIR in situ monitoring system [22]. The view cell was equipped with two sapphire windows, facilitating the in-line FTNIR spectroscopic monitoring of the phase behaviors during the polymerization process.…”

“…Then BPO (or AIBN) was added into the view cell via a set of high-pressure sample-in tube by the aid of the pressurized CO 2 to initiate the polymerization. After the pressure was rapidly increased to 25 MPa (within 3 min), FT-NIR spectra were started to be in situ collected periodically during the polymerization processes, via which the monomer conversion was determined using the identical method recently reported [22]. When the system continuously polymerized for 8 hours or became cloudy [22,30,31] (where the baseline absorbance exceeded 3.0 [21]), the view cell was cooled and depressurized.…”

“…The number-average molecular weight (M n ) of the obtained non fluorinated polymers was analyzed using a Waters-Breeze gel permeation chromatography (GPC, Waters, Milford, CT, USA) where tetrahydrofuran (THF) was used as the eluent at a flow rate of 1.0 mL•min −1 and monodisperse polystyrene standards were applied to calibrate the relative molecular weight. The molecular weight of the poly 2,2,2-trifluoromethyl methacrylate (PMTFMA) was analyzed using a Microflex matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF mass, Bruker-Dalton, Bremen, Germany) followed a similar process to that in our recent work [22] except that dithranol was used as the matrix.…”

“…While based on the experimental results and the theoretical calculations in perfluorooctanoic acid (FOA) + scCO 2 system, it is reported that the interaction between the carbonyl group and CO 2 may contribute more than that between C-F and CO 2 to the attraction with CO 2 [21]. So far high pressure in situ Fourier transform infrared/near infrared (HP FTIR/NIR) has been proved to be one of the most effective techniques to investigate the intermolecular interactions as well as the thermodynamic and kinetic properties in the scCO 2 system [20,22]. Besides, ab initio/theoretical calculation is believed to be a most promising complement method to understand the interactions in scCO 2 system [23][24][25].…”

Perfluorocyclobutyl Aryl Ether-Based ABC Amphiphilic Triblock Copolymer

“…The cost-effectiveness, easy processability, and good reactivity of fluorinated methacrylates make the products more attractive23. In addition, because of the remarkably low surface energies, stain resistance, low friction coefficients, and good optical properties, such fluorinated polymethacrylates may be attractive for the preparation of high performance coating surfaces, medical materials, functional membranes, optical devices, and fibers24252627.…”