Nuclear magnetic resonance study of vinylidene fluoride and trifluorochloroethylene copolymers

A Fluorine-19 NMR Study of the Microstructure of Vinylidene Fluoride–Trifluoroethylene Copolymers

“…In a previous paper/ 5 we dealt with the microstructure of poly(trifluoroethylene) (PTRFE) with regard to the head-to-tail (H-T), head-to-head (H-H), tail-to-tail (T-T), and tail-to-head (T-H) structures using 19 F NMR and a Monte Carlo simulation, and found that the amount of the normal H-T structures is very small in a polymer chain.…”

High-Resolution Variable-Temperature 19F MAS NMR Spectroscopy of Vinylidene Fluoride Based Fluoropolymers

“…7,8 Muresheva developed the following equation for determining the monomer ratio for VF 2 and CTFE copolymers. 7 The following assumptions were used in the derivation Table 3.…”

“…Our assignments of peaks into the five-carbon sequence units shown in Table are based on the assignments of Muresheva. , Muresheva developed the following equation for determining the monomer ratio for VF 2 and CTFE copolymers The following assumptions were used in the derivation of eq 3: (1) The number of CTFE−CTFE−CTFE sequences is low compared to the number of CTFE−CTFE−VF 2 type sequences.…”

“…Chemical shifts were referenced to polytetrafluoroethylene, which was assigned a chemical shift of −121 ppm. Five-carbon sequences were assigned to particular resonances on the basis of solution-state studies of similar compounds. − , Integrated areas of peaks in each spectrum were measured for each compound, and calculations of monomer ratios were based on these values. We estimate that each of the fixed integration values has an error of ±0.1%.…”

“…A valuable tool for the analysis of the structure of fluorocarbon polymers is 19 F NMR spectroscopy. , In 19 F NMR, neighbors of a particular fluorine nucleus have a significant effect on its chemical shift. As a result, the type and quantity of monomer sequences can be determined in a fluorocarbon polymer on the basis of 19 F chemical shifts. − The routine analysis of fluoropolymers and monomer ratio determination via 19 F NMR spectroscopy have typically required the polymers to be in solution. Many fluoropolymers, however, are insoluble or intractable and therefore require analysis in the solid state.…”