Polymerization of novel trifluorovinyl ethers: Insight into the mechanisms of termination and chain transfer

Abstract

New trifluorovinyl ether polymers were synthesized with the view toward overcoming the high chemical and thermal stabilities commonly associated with fluoropolymers. Trifluorovinyl ether copolymers, with fluorinated pendant groups, have previously been prepared to overcome limitations in processibility. To further enhance solubility in common organic solvents and to improve processibility, we prepared three new trifluorovinyl ether monomers, having hydrocarbon ether pendant groups, for polymerization: 1‐[2‐(2‐ethoxy ethoxy)ethoxy]‐1,2,2‐trifluoroethene (Et‐TFVE), 1‐[2‐(2‐t‐butoxy ethoxy)ethoxy]‐1,2,2‐trifluoroethene (t‐Bu‐TFVE), and 1‐(2‐phenoxy ethoxy)‐1,2,2‐trifluoroethene (Ph‐TFVE). Homopolymers of these three monomers were prepared by aqueous emulsion polymerization with the use of a redox initiator. Poly(Et‐TFVE) and poly(Ph‐TFVE) were prepared with a range of molar masses, the highest of which had weight average molar masses of 33,800 g mol−1 and 59,000 g mol−1, respectively. As a result of monomer reactivity and structure, the polymerization mechanism was complicated, resulting in β‐scission termination/chain transfer for all three polymers and hydrogen abstraction chain transfer for poly(Et‐TFVE) and poly(t‐Bu‐TFVE). To the best of our knowledge, this is the first example of hydrogen abstraction from the pendant group of the trifluorovinyl ether itself. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3301–3308, 1999

Insights into the Properties of Novel Trifluorovinyl Ether Copolymers

“…Figure a) and hydrogen-abstraction (cf. Figure b) termination/chain-transfer reactions . Evidence for β-scission was provided by FTIR data with the presence of a carbonyl peak at 1775 cm -1 ascribed to a carboxylic acid by comparison to a small molecule analogue (ClF 2 CCO 2 H) and previous experimental results .…”

“…The polymers were prepared by a redox-initiated aqueous emulsion polymerization using potassium persulfate, ferrous ion, and sodium bisulfite. We took advantage of previous experimental data that suggested the polymerization conditions: 20 °C, 5 wt % surfactant (relative to monomer) and 3 × 10 -5 M iron(II) concentration . All reactions proceeded for 2 days, after which the emulsion was broken and the polymer purified.…”

“…A series of copolymers were prepared by varying the composition of Et-TFVE and t -Bu-TFVE monomers in the feed. The 1 H NMR data were used to calculate copolymer composition, according to eq 1; however, 1 H NMR could not be used to determine molecular weight because of the possibility of multiple hydride ends per polymer chain . As shown in Table , seven polymers were prepared with t -Bu-TFVE compositions ranging from 0 to 100 mol %.…”

“…We recently reported the synthesis 5 and polymerization mechanism 6 of two novel TFVEs, namely, 1-[2-(2ethoxy-ethoxy)-ethoxy]-1,2,2-trifluoroethene (Et-TFVE) and 1-[2-(2-tertiary-butoxy-ethoxy)-ethoxy]-1,2,2-trifluoroethene (t-Bu-TFVE). As shown in Figure 1, the polymers predominantly have a fluorocarbon backbone and a hydrocarbon, oligoether pendant group, with a structure similar to that of poly(ethylene glycol) (PEG).…”

Copolymers of 3,3,3‐trifluoropropene and vinyl acetate: Synthesis, characterization, and hydrolysis

“…To overcome this problem, various solvent‐soluble fluoropolymers have recently been developed. Shoichet4 and others5, 6 have synthesized trifluorovinyl ether (TFVE) polymers, which have a hydrocarbon oligoether pendant group and a fluorinated backbone, thereby incorporating some hydrocarbon properties into a fluorinated system. The polymers are easier to process and more soluble in organic solvents.…”