A STUDY OF INVERSIONS IN ETHYLENE-PROPYLENE COPOLYMERS

To account for the dependence of the amount of (CH2)2 groups contained in ethylene-propylene copolymers upon the composition and the product of reactivity ratios, we derived an equation containing two empirical parameters deduced from the i.r. spectrum of several copolymers, prepared by some vanadium based catalysts, and of the corresponding homopolymers of propylene. Our treatment shows that, with these catalysts, there is a probability of about 80 per cent for the entrance of an ethylene unit and of about 20 per cent of a normal propylene unit after an inverted propylene unit; it shows that two thirds of the propylene units in EP diads add normally (i.e. at the methylene group). © 1969.