NMR study of molecular chain structure of polyvinylidene fluoride

Abstract

synopsisImproved resolution of the 40 and 56.4 Mcycle F19 NMR room temperature spectra of solutions of polyvinylidene fluoride in dimethylacetamide has resulted in a clearer understanding of the polymer chain structure. The spectra indicate that the structure of polyvinylidene fluoride consists predominantly of head-to-tail sequences of -CHz-CF2-monomer links, with 5 4

Low-temperature fluorination of fluoro-containing polymers

“…NMR studies of PVDF have demonstrated that only 5-6% of the polymer is connected ''head-to-head'' consistent with other samples [12]. On the basis of a thermomechanical approach [13], we estimate that the chain lengths of the polymers in the granules of PVDF and CTE are $550 and 675, respectively.…”

“…At low temperatures, fluorine reacts only with the small fraction of the polymer in PVDF, which is formed as a result of ''head-tohead'' monomer polymerization leading to PVDF having two adjacent -CH 2 -groups. Indeed, NMR experiments showed [12] that PVDF contains about 5-6% of polymer sections connected ''head-to-head''. This is consistent with the lower concentration of radicals in fluorinated PVDF and with the fact that only a small percent change was observed in the EDX experiments.…”

Morphology of polyvinylidenefluoride and the copolymer of tetrafluoroethylene with ethylene using thermomechanical analysis

“…NMR studies of PVDF have demonstrated that only 5-6% of the polymer is connected ''head-to-head'' consistent with other samples. 23 The degree of regular alternation of the monomers in the polymers was examined by IR spectroscopy of the CH 2 groups at 2950 and 2973 cm 21 , and the results were consistent with a completely alternating polymer. The granules of PVDF are truncated cylinders with a 3 mm diameter and a 4 mm length.…”

“…in which m e is the concentration of inter central chains of a network in mol cm 23 , R, the gas constant, T ' , the temperature where a value for a high elasticity plateaus is obtained. Having substituted eq.…”

The NMR of Polymers

“…71), plotted with a frequency of 56.4 MHz [718] (see also [722]) and 4 fluorine lines are found corresponding to the structures: From the relative intensities of the lines it is possible to calculate the content of "head-to-tail," "head-to-head," "tail-to-tail," and "tail-to-head" structures, and thus to determine the microstructure of the chain completely.…”