In Line Spectroscopic Investigation of Fluorinated Copolymer Synthesis in Supercritical Carbon Dioxide

Abstract

AbstractSummary: In‐line Fourier Transform – near infrared (FT‐NIR) spectroscopy is a very elegant method to follow conversion as well as phase behaviour throughout a reaction. It was applied to two examples of homogeneous phase syntheses of fluorinated copolymers in supercritical carbon dioxide (scCO2). The conventional free radical copolymerization of vinylidene fluoride (VDF) and hexafluoropropene (HFP) on the one hand side, and the Activators Generated by Electron Transfer (AGET) Atom Transfer Radical Polymerization (ATRP) of F‐decene (1H‐1H, 2H perfluoro‐1‐decene) and tBA (tert‐butyl acrylate) on the other hand side were studied. Poly(VDF‐co‐HFP) were synthesized at 75 and 100 °C at pressures above 800 bar to remain in solution, even at high VDF contents. The reactivity ratios, r, were determined from a small number of experiments using the entire conversion vs. time data from in‐line FT‐NIR measurements. The estimated values are rVDF = 4.3 and rHFP = 0.1. In the case of poly(F‐decene‐co‐tBA), a fluorinated macroligand was introduced for AGET ATRP. Molecular weights between 10000 and 40000 g/mol and polydispersities between 1.1 and 2.1 were obtained while remaining in homogeneous phase. Reactivity ratios were determined as rF‐decene = 0.02 and rtBA = 9.1.