Rheological behavior of polypropylene/layered silicate nanocomposites prepared by melt compounding in shear and elongational flows

Abstract

Melt rheology and processability of exfoliated polypropylene (PP)/layered silicate nanocomposites were investigated. The nanocomposites were prepared by melt compounding process in the presence or absence of a PP-based maleic anhydride compatibilizer. PP/layered silicate nanocomposites showed typical rheological properties of exfoliated nanocomposites such as nonterminal solid-like plateau behavior at low frequency region in oscillatory shear flow, higher steady shear viscosity at low shear rate region, and outstanding strain hardening behavior in uniaxial elongational flow. The melt processability of exfoliated PP/layered silicate nano-composites was significantly improved due to good dispersion of layered silicates and increased molecular interaction between the PP matrix and the layered silicate organoclay. Small-angle X-ray scattering and transmission electron microscopy results revealed that the layered silicate organoclay was exfoliated and good interaction between PP matrix and organoclay was achieved by using the PP-g-MAH compatibilizer.

The effects of processing and using different types of clay on the mechanical, thermal and rheological properties of high-impact polystyrene nanocomposites

“…The complex viscosity decreases irregularly with an increasing frequency, indicating a shear thinning effect caused by the orientation of the silicate layers parallel to the flow direction. 24,26 Figure 8 shows how the storage modulus (G 0 ) varies as a function of the angular frequency. The storage modulus exhibits a similar trend when compared with the complex viscosity, where the values of the storage modulus for all blends studied at all frequency regions increases with increasing clay content.…”

“…25,28,35 They consider the values of g 0 and g 00 to represent the extent of interaction between the organoclay platelets and the polymer chains. The slope of the storage modulus is expected to have a value of 2, whereas the slope of the loss modulus is expected to have a value of 1 for monodispersed polymers, 26 which decreases to 0 for threedimensional nanocomposite structures. 30,35 Table 2 shows the slope of the storage modulus for HIPS and HIPS nanocomposites.…”

“…Many articles reported a correlation between the morphological and rheological properties of nanocomposite materials. [24][25][26][27] Hoffmann et al 28 considered the effect of material morphology on the rheological properties of the material. They correlated the slope of the storage modulus to the formation of the network structure.…”

Influence of Surfactant Functional Groups on Morphology and Rheology of Polypropylene/Organoclay Nanocomposites

“…For most nanocomposites, the strain hardening behavior is usually attributed to good dispersion of layered silicates and strong interactions among the matrix, layered silicates, and compatibilizer. [3] . However, the strain hardening observed here could not be explained on the basis of only on the dispersion state of layered silicates.…”

“…[1][2][3] The dramatic enhancement in material performance is related to the uniform distribution of highly anisotropic nanoscale reinforcements in the polymer matrix. Structurally, two types of polymer/clay nanocomposite structures can be obtained.…”