Emulsion copolymerization of tetrafluoroethylene with ω‐chlorotetrafluoroethyltrifluorovinyl ether and the synthesized copolymer properties

Abstract

Emulsion copolymerization of ω‐chlorotetrafluoroethyltrifluorovinyl ether (Cl(CF2)2OCF = CF2 (FVE)) with tetrafluoroethylene (CF2 = CF2 (TFE)) was investigated at various monomer ratios. The copolymerization rate is below the rate of TFE homopolymerization and the copolymerization kinetics depends on the FVE content in the reaction medium. The copolymer composition is very similar if the FVE content in monomer mixture is ≤2.5 mol %. However, the percent amount of FVE in the copolymer, the copolymerization rate, and molecular mass of synthesized copolymers decrease noticeably with increase in the FVE content in the monomer mixture. The constants of copolymerization are r1= 2.8 (TFE) and r2 = 0.03 (FVE). The copolymer is a statistical polymer consisting of TFE blocks and individual FVE molecules between the blocks. The average molecular mass of copolymers is significantly less than that of the TFE homopolymer (PTFE) synthesized at the same conditions. The morphologies of PTFE and copolymer powders were investigated by thermomechanical analysis and are not similar. The copolymer has a completely amorphous diblock morphology depending on the FVE content. The introduction of FVE molecules into the copolymer macromolecules is accompanied by reduction of the crystalline portion of copolymer. If the FVE content in copolymer is ≥3.5 mol %, the copolymer macromolecules completely lose the ability to form crystalline portions as a result of their amorphicity. The introduction of up to 2.4 mol % FVE into the copolymer macromolecules yields a highly thermostable and meltable copolymer which can be processed by using the industrial processes used widely for thermoplastics. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Monomer Partitioning in Emulsion Polymerization of Perfluorinated Ionomers

“…The model describes well the experimental data of copolymer composition when the following values of the reactivity ratios are applied: r TFE = 7.5 and r TFE = 0.01 (joint confidence region in Supporting Information, Figure S4). The largely different values for the two monomers are quite expected, 44,45 given the much larger reactivity of TFE. This aspect is reflected in a copolymer chain being close to a PTFE backbone with a few sulfonyl side chains.…”