The present invention relates to the post-polymerization fluorination methods of polymers produced via ring-opening metathesis polymerization. Unlike prior art methods that result in low product yields and generally involve chemically aggressive reagents, the inventive methods produce fluorinated polymers in quantitative yields and under mild conditions. In preferred embodiments, a source of difluorocarbene is reacted with the desired polydiene to form a fluorinated polymer product. In preferred embodiments, the source of difluorocarbene is hexafluoropropylene oxide and the polydiene is poly-dicyclopentadiene (“poly-DCPD”). Fluorination and the concomitant removal of unsaturated bonds result in polymers having improved physical properties such as improved strength characteristics, enhanced oxidative and chemical stability, and low surface energies.