Fluorine spectrum analysis and structural characterization of Y-type perfluoropolyether carboxylic acid
Perfluoropolyether and their derivatives(PFPEs)are a class of fluoropolymers with high added value.Their specific physicochemical properties make them have a good commercial prospect.At present,domestic related products are heavily dependent on imports,and there is a lack of research on PFPEs,especially on Y-type PFPEs,so it is urgent to strengthen the development and research in related fields.Nuclear magnetic resonance fluorine spectroscopy(19F NMR)is an important technique for the structure analysis of perfluorinated polyether compounds.However,due to technical blockade and difficulties in preparation,the analysis of 19F NMR spectroscopy of Y-type PFPE carboxylic acid(PFPE-CA)is still not perfect.In this study,appropriate sample preparation conditions were used to obtain a clear 19F NMR spectrum of Y-type PFPE-CA,and chemical shifts of F atoms in different chemical environments in the main chain and end group were assigned.The composition of the active mixture and the number average molecular weight of the sample can be calculated by integrating the spectral peaks.This analysis method is accurate and fast,and provides a research basis for the breakthrough of production and separation technology of Y-type PFPEs.
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