Disclosed is a method of functionalizing a vinyl terminated polyolefin, the method comprising combining a vinyl terminated polyolefin and a α,β-unsaturated carbonyl compound at a temperature of at least 150° C. and a pressure of at least 14 psi, forming a functionalized polyolefin. The functionalized polyolefin comprises a compound or mixture of compounds represented the formula: wherein each R1 is, independently, selected from hydrogen and C1 to C4 or C10 alkyls; n is an integer from 2 to 800; and each X is, independently, a functional group derived from the α,β-unsaturated carbonyl compound.