Fluoroelastomers: Reaction Products in Early Stages of Network Formation
Reactions occurring in the first steps of crosslinking of vinylidene fluoride (VDF)-hexafluoropropene (HFP) elastomer copolymers (molar ratio 4/1) are investigated operating in homogeneous solution, phase transfer catalysis conditions and bulk. Two kinds of principal unsaturation, monitored by FT-IR and 1H-NMR spectrometry, -CH=CF- and (CF3)C=CH-, have been detected. The former seems to be the curing site in the nucleophilic crosslinking of the fluoroelastomer. Polymer chain scission is also observed and has to be related to the HFP units as well as to the base content in the system.
KeywordsAlkaline Treatment Vinylidene Fluoride Homogeneous Phase Phase Transfer Catalysis Onium Salt
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