We report two sets of independent nuclear magnetic resonance (NMR) measurements of self-diffusion and proton transverse relaxation in molten cis1,4-polybutadiene (PB) performed in order to investigate chain dynamics properties. Self-diffusion coefficients were measured as a function of temperature and of molecular weight (M) over the range 10(4) to 6.7x10(4) g/mol. The crossover from the Rouse-type behavior (Dapproximate toM(-1)) to the reptation one was found to occur for M(Cross)approximate to3x10(4) g/mol; for M>M-Cross the data were consistent with the scaling dependence: Dapproximate toM(-2.4+/-0.05), in agreement with the data analysis recently reported in the literature. The thorough analysis of the transverse relaxation of protons attached to highly entangled PB chains (6.7x10(4)less than or equal toMless than or equal to43x10(4) g/mol) gave evidence for the dynamics partition of one chain into two end-submolecules and one inner part clearly discriminated from one another. The number N-End of monomeric units in one end-submolecule, independent of M, is shown to be closely related to the monomeric friction coefficient zeta(0) measured from short chain diffusion over the temperature range 25 to 85 degreesC. The interpretation both of diffusion results and of proton relaxation of inner monomeric units lead to the definition of an effective friction coefficient zeta(0)(Eff)approximate tozeta(0)(M/N-End)(0.4) associated with the curvilinear diffusion of one chain in its tube. The friction coefficient zeta(Loc) associated with local monomeric rotations is discriminated from zeta(0) from its weaker temperature dependence. This approach was applied to polyethylene-oxide chains in solution (dimethyl formamide, 0.18less than or equal tocless than or equal to1, w/w) where the segmental size of end-submolecules was found to vary as 1/c. Experimental results are well matched by this specific NMR approach which accounts for the novel properties of the proton relaxation function.