Polybutadiene (PB)／Montmorillonite (MMT) nanocomposites were prepared by in situ polymerization through anionic polymerization technique．The structure of the nanocomposites was characterized by using XRD and H-NMR. XRD results showed that the crystalline spacing in clay was increased

indicating the intercalation of PB chains in MMT crystallites

and both intercalated and exfoliated nanocomposites were prepared．From the H-NMR spectra of PB and PB／MMT nanocomposites

it could be seen that the microstucture of PB was influenced by MMT．The 1

2 units content of PB molecules increased with the introduction of MMT．The dynamic properties of nanocomposites were measured by DMA．The results showed that Tg and storage modulus were increased

tanδ was decreased with MMT added

indicating that MMT has strong interaction with PB so as to reduce the friction among the chains of PB．The results of TGA revealed that the nanocomposites have better thermal stability than PB.