Abstract: In order to reveal how the dehydrofluorination of poly(VDF-co-HFP) copolymer and poly(VDF-ter-HFP-ter-TFE) terpolymer takes place in alkaline environment, the reaction mechanisms of different fluoroelastomers were studied systematically in this paper. Not only the chain structures of fluoroelastomers, but also the sequence types and contents of double bonds and other oxygen-containing groups of products were all analyzed and investigated by Attenuated total reflectance/Fourier transform infrared (ATR-FTIR),1H nuclear magnetic resonance (NMR),19F-NMR spectroscopy. The results revealed that when two kinds of fluo-roelastomers exist in alkaline environment, the dehydrofluorination would accompain with rearrangement reaction and oxidation reaction. The dehydrofluorination of poly(VDF-co-HFP) copolymer was mainly conformed to Zaitsev’s rule and Hofmann’s rule supplemented, the double bonds generated in five positions of molecular chains. In contrast, the dehydrofluorination of poly(VDF-ter-HFP-ter-TFE) terpolymer was opposite, which was mainly conformed to Hofmann’s rule and Zaitsev’s rule supplemented, the double bonds generated in seven positions of molecular chains. Furthermore, with the oxidation reaction occurring, the sequence types of double bonds which were conformed to Hofmann’s rule would be converted to hydroxyl groups. Under the same conditions, the contents of double bonds and hydroxyl of poly(VDF-ter-HFP-ter-TFE) terpolymer were higher than that of poly(VDF-co-HFP) copolymer after the reaction.
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2018, Vol. 32 
