The aim of this experiment is to explore the segmental mode of natural rubber NR by means of quasielastic neutron scattering, QENS, and observe the influence of natural crosslinking.We will characterize the segmental dynamics of NR getting temporal and spatial information through the incoherent scattering function. In the proposed experiment, we aim to compare the dynamics of the gel phase of NR with that Segmental Mode corresponding to the isolated polyisoprene chains fraction, as well as with that of synthetic polysisoprene which has been previously studied by means of QENS and neutron spin echo. In this proposal we aim to answer the following questions:- Does the segmental mode in NR at the ps time scale - depend on natural cross-linking and how does it compare to the synthetic polymer?- What is the geometry of the motion underlying this dynamic mode?