Differences between theoretical and experimental values are minimized when the fraction of SBR in blends increases as it can be observed in the sample 25NR/75SBR where the dipolar coupling value obtained experimentally are equal to the the- oretical one. The different behavior between these two complementary samples can be attributed to the migration of cura- tives, that in the pair NR-SBR occurs from SBR towards NR [42].