STUDIES ON MICROSTRUCTURE OF POLY(TRIFLUOROETHYLENE) CHAIN BY F-19 NMR AND MONTE-CARLO SIMULATION

An investigation was carried out on the molecular microstructure of poly(trifluoroethylene) (PTRFE). With the high-resolution 19F-NMR spectrum of PTRFE and the computer simulation of the same polymerization system, the amount of backward-added monomer units and their distribution in polymer chain were estimated. The distribution is represented by the reactivity ratios of head- and tail-position of the unsymmetrical monomer to each propagating polymer radical. The assignment of absorption peaks of 19F-NMR spectrum of PTRFE was made on an empirical basis, and four possible structures, containing 5 carbon atoms along the polymer chain with a –CF2– group as the central group, were figured out. The percentage of backward-added trifluoroethylene (TRFE) in the PTRFE chain polymerized at 22°C was 50%. Denoting CFH-position CF2-position in TRFE (CFH=CF2) by B and A, respectively, the reactivity ratio of B and A of TRFE to the – – – CF· radical was estimated as B/A=1/0.75 and that of TRFE to the – – – CFCF2· radical was 1/1.33. © 1979, The Society of Polymer Science, Japan. All rights reserved.