Nuclear magnetic resonance spectroscopy (NMR), differential scanning calorimetry (DSC), wide and small angle X-ray scattering (WAXS and SAXS) investigation have been used in order to achieve a molecular, thermal and structural characterization of a sample of propylene-butadiene copolymer containing 3% (wt/wt) of butadiene (uPP) and of uPP samples modified by grafting polymethylmethacrylate (upp-g-PMMA) and polystyrene (uPP-g-PS). The uPP copolymer was synthesized by Himont according to method patented by Himont [1], that allows, by means of the use of a proper catalyst system, co-polymers of propylene with diene having conjugated double bonds in which at least 20% of the unsaturations is of the vinyl type to be obtained. The influence of concentration, distribution and type of the uncrystallizable comonomer units on the thermal behaviour of such co-polymers and on the kinetic, morphologic and thermodynamic parameters related to crystallization process from melt have been also investigated.