This work presents the correlation between the organization of an organically modified montmorillonite (OMt)
and the dynamic-mechanical properties of polymer nanocomposites containing a hybrid filler system, based on
carbon black (CB) and OMt. Clay polymer nanocomposites (CPN) were prepared by melt blending synthetic
poly(1,4-cis-isoprene) (PI), carbon black (CB) and OMt. Two types of OMt were used: with ammonium cations
intercalated between the clay mineral layers (I-OMt) and delaminated (D-OMt). The latter was obtained via
ball milling of I-OMt and presented a degree of delamination higher than 95%, as revealed by X-ray diffraction
(XRD) analysis. The structure of CPN was studied with XRD and transmission electronmicroscopy (TEM) analyses.
The mechanical behavior of uncrosslinked masterbatches and of nanocomposites crosslinked with sulfur
based systems was assessed with dynamic shear experiments, by measuring the time needed to recover the
initialmodulus after a large strain perturbation and by obtainingmaster curves for the dependence of the storage
modulus on frequency. I-OMt is shown to promote the filler networking phenomenon more easily than D-OMt:
the storage modulus has a stronger reductionwith the strain amplitude and a longer rubbery plateau is featured
on the frequency scale.Modulus recoverymeasurements revealed that the structure of CPN can be restored after
the application of large strain amplitudes. The extent of OMt delamination is presented as a key feature to control
the dynamic-mechanical properties of CPN containing a filler, such as CB, suitable to establish an intimate
interaction with OMt. The partial substitution of CB with D-OMt allowed the preparation of crosslinked nanocomposites
with lower Payne effect.