Abstract: The present invention relates to macromonomer compounds having the formula (I) where R1 is hydrogen, halogen, and optionally substituted alkyl, aryl, alkylaryl or arylalkyl radical; R2 and R3, which can be similar or different, are hydrogen, halogen, alkyl, aryl, alkylaryl, arylalkyl or alkoxy radical; R4 is an optionally substituted alkyl, aryl, alkylaryl or arylalkyl radical, or —XR5, with R5 being hydrogen, and optionally substituted alkyl, aryl, alkylaryl or aryalkyl; X is oxygen or sulphur; A corresponds to a unit issued from at least one ethylenically unsaturated monomer; and n is comprised between 1 and 10000. The invention also relates to dienic compounds having the formula (II): H2C═CR1—CH═CH—C(R2)(R3)—X2—R6 wherein R1 R2, R3 and X have the same meaning as above and R6 represents R5 or a group —COR7 or —COOR7 with R7 being alkyl, aryl, alkylaryl or arylalkyl.