Radical copolymerization of ethylene with vinyl phosphonates under pressure

Abstract

The reactivities (composition curves) found during the copolymerization of ethylene, as well as the copolymer densitities as a function of composition, have been used to divide the CH 2=CHPO(OR) 2 (M 2) monomers into 2 groups: 1) R=C 6 H 5 and C 2H 4Cl and 2) R=C 4 H 9 and iso-C 4H 9. This correlates well with the polarity differences of M 2. The first group is characterized by higher reactivities, especially when the M 2 content in the reaction mixture is high. The rapid drop of the reaction rate and of the mol. wt. of the copolymers, when the M 2 content is increased in the reaction mixture, and the relatively large rate of the M 2 homopolymerization, can be explained by the competition of the two mechanisms of chain transfer. An intramolecular reaction is dominant at the start and yields an intermediate P ∗ radical. Chain transfer is faster at a larger M 2 content and hydrogen will dissociate from R.