Analysis of dynamic oscillatory rheological properties of PP/EVA/organo-modified LDH ternary hybrids based on generalized Newtonian fluid and generalized linear viscoelastic approaches

Abstract

A comprehensive investigation was performed on single-step melt processed polypropylene (PP)/(ethylene vinyl acetate copolymer (EVA)/organo-modified layered double hydroxide (LDH) counterpart ternary hybrids to explore the effect of LDH loading on small-amplitude oscillatory shear (SAOS) rheological properties and to correlate the properties with microstructure. The rheological results were analyzed in detail from qualitative and quantitative perspectives. Using qualitative interoperation of storage modulus and complex viscosity alteration against LDH loading, and also quantitative analysis by viscosity models based on both the generalized Newtonian fluid (GNF) and generalized linear viscoelastic (GLVE) approaches, detailed predictions were carried out on the microstructure of samples and also partitioning of the organo-modified LDH particles and their intercalation and exfoliation extent within hybrids. By comparing the elasticity and relaxation spectrum of PP-rich/LDH with those of EVA-rich/LDH hybrids, it was predicted that organo-modified LDH platelets, in the case of PP-rich samples, have been located at the interface or within the EVA dispersed particles, while in the case of EVA-rich samples, they mainly localized within the matrix. In addition, the crossover frequency and slope of G 0 and G 00 curve at terminal region were correlated with the extent of intercalated and exfoliated structures of filler. The validity of these predictions on microstructure of the developed hybrids was confirmed visually using transmission electron microscope (TEM) micrographs.

The Structure and Properties of Medical Disposable Protective Clothing Materials with Different Packaging and Models under γ Irradiation

“…As ω increases, the molecular chains of polypropylene, polyethylene, and other molecules become disentangled. The shear thinning phenomenon in the low‐frequency region indicates that entanglement of the PE and PP molecular chains into a phase‐separated network structure has occurred with increasing time [28] . Figure S5b shows that the G′‐ω curves of the four types of disposable medical protective clothing materials are similar to the [η*]‐ω curves, with almost overlapping curves and exhibiting a plateau modulus in the low‐frequency region.…”

“…The shear thinning phenomenon in the low-frequency region indicates that entanglement of the PE and PP molecular chains into a phase-separated network structure has occurred with increasing time. [28] Figure S5b shows that the G'-ω curves of the four types of disposable medical protective clothing materials are similar to the [η*]-ω curves, with almost overlapping curves and exhibiting a plateau modulus in the low-frequency region. This suggests that there is a structural property in the melt of the four types of disposable medical protective clothing materials, which is the same as the explanation for the [η*]-ω curves.…”

Synthesis and Characterization of New Layered Double Hydroxide-Polyolefin Film Nanocomposites with Special Optical Properties

“…This finding might indicate that we are reaching the percolation concentration in the melting state. Therefore, an effective interaction between the LDH and PE happens and the viscoelastic properties undergo this limited increase [49]. On the other hand, a drop of G′ and G″ when SPAN is added to the nanocomposite is observed.…”

Tuning the nano/micro‐structure and properties of melt‐processed ternary composites of polypropylene/ethylene vinyl acetate blend and nanoclay: The influence of kinetic and thermodynamic parameters

“…The subsequent morphological analysis showed uniform dispersion of the EVA compatibilizer and the organoclay in the main PP phase, producing intercalated composites. A significant amount of work has been published on PP/EVA/nanoclay composites, [16][17][18][19][20][21][22][23] migration of fillers, and mixing sequences in ternary polymer blend composites 24 ; however, to the best of our knowledge, only one study 23 has explored how organoclay incorporation affects the blend morphology and the spatial distribution of the nanoclay, and how these factors in turn affect the mechanical properties. The authors of this study 23 only focused on the effect of the blending sequence on the morphology and properties of ternary nanocomposites using a twin-screw extruder, but did not investigate the kinetics of nanoclay migration in composites, the kinetics of microstructure formation, or the relation between microstructural differences and the properties of the nanocomposites.…”