Role of polymer–clay interactions and nano-clay dispersion on the viscoelastic response of supercritical CO2 dispersed polyvinylmethylether (PVME)–Clay nanocomposites

Manitiu, Mihai; Horsch, Steven; Gulari, Esin; Kannan, Rangaramanujam M.

doi:10.1016/j.polymer.2009.05.036

Cited by 32 publications

(21 citation statements)

References 35 publications

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“…1,2 The bulk properties in composites are known to be functions of the volume fraction, dispersion state, and orientation of the platelet particles as well as the inherent properties of the different components that constitutes the composites. 2,3 Aerogels are representatives of an emerging class of structural materials with ultralow densities as well as high porosity (void fractions of ∼95%), which hold promise for a wide variety of applications ranging from packaging/insulating to absorption materials. [4][5][6][7][8][9][10][11][12] Through a robust and environmentally benign freeze-drying process, layered silicates can be converted into the "house of cards"-like aerogels, produced in the grain boundaries of ice crystals, with bulk densities typically in the range between 0.02 and 0.15 g cm -3 .…”

Section: Introductionmentioning

confidence: 99%

Solution Cross-Linked Natural Rubber (NR)/Clay Aerogel Composites

et al. 2011

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Aerogels are structural materials with ultralow bulk densities (often less than 0.1 g cm -3 ), which stand out as good candidates for a variety of applications. In the present study, natural rubber (NR)/ clay aerogel composites were produced by freeze-drying of the aqueous aerogel precursor suspensions, followed by solution cross-linking of the aerogel samples in benzene using sulfur monochloride (S 2 Cl 2 ) as a cross-linking agent. The influences of cross-linking conditions, i.e., cross-linker concentration and reaction temperature, as well as polymer loading on the aerogel structure and properties were investigated. 1% (v/v) of S 2 Cl 2 and reaction temperature of -18°C were found to be the optimum conditions for producing a strong and tough rubber composite; the 2.5 wt % NR aerogel, for example, after being cross-linked, exhibited a compressive modulus of 1.8 MPa, 26 times higher than that of the neat control. These favorable mechanical properties are attributed to the high local concentration of rubber and S 2 Cl 2 in the freeze-dried structures, giving rise to the high cross-linking efficiency. Increasing the rubber concentration led to a substantial increase in the mechanical strength, in accord with the changes in microstructure and degree of cross-linking. The swelling capacity of the NR aerogels decreased with either increasing the cross-linker concentration or decreasing the weight fraction of rubber. Cross-linking of the rubber aerogels brought about increased thermal stability, consistent with restricted thermal motion of NR chains.

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Section: Introductionmentioning

confidence: 99%

Solution Cross-Linked Natural Rubber (NR)/Clay Aerogel Composites

et al. 2011

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“…scCO 2 pre‐treatment of the organoclay to form s‐C20A has been established in earlier work to cause surfactant rearrangement, leading to basal expansion and increased organic coverage over the silicate surface . The rapid depressurization used by the pre‐treatment method has also been reported by other researchers to cause clay exfoliation . Therefore, the swollen or pre‐exfoliated clay particles would be expected to more readily delaminate in a shear‐flow or extensional‐flow field due to the diminished or negligible van der Waals forces between individual platelets (or small tactoid sections).…”

Section: Discussionmentioning

confidence: 92%

“…Supercritical CO 2 (scCO 2 ) has been used to a great extent in the development of foaming thermoplastics for the last two decades and, more recently, research efforts have been undertaken to utilize scCO 2 as a dispersion aid for nanocomposites without necessarily producing a foam [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. If this could be accomplished, it would be expected that the resulting materials would possess higher specific modulus values than conventionally reinforced thermoplastics and would result in lighter parts at the same stiffness.…”

Section: Introductionmentioning

confidence: 99%

Use of supercritical CO₂ as a dispersing agent in the preparation of a polymer‐layered silicate nanocomposite

2015

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The usefulness of supercritical CO2 (scCO2) in the processing of thermoplastic olefin (TPO) nanocomposites was investigated using a simple extensional flow mixing device. An organoclay (Cloisite® 20A), a maleated polypropylene (Polybond® 3200), and a TPO polymer were selected for this study. The three components were combined in different manners to evaluate how scCO2 influenced the microstructure of a final nanocomposite prepared by different mixing orders of the formulation components. The organoclay was examined in its as‐supplied state as well as after being conditioned under scCO2. Analyses of the nanocomposites by X‐ray diffraction, transmission electron microscopy, and parallel plate rheology techniques showed that inclusion of scCO2 during melt compounding significantly contributed to disrupting the crystalline order in the structure of the original organoclay. However, the order by which the formulation components are combined under scCO2 was important to clay dispersion. It was shown that making use of the proper combination order led to an improvement in the modulus of the resulting nanocomposites as measured by rheology. POLYM. COMPOS., 38:987–995, 2017. © 2015 Society of Plastics Engineers

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“…' Clays dispersion and polymer-clays interactions play a key role in producing property enhancements in nanocomposites. In Manitiu et al (2009), the impact of nano-clay dispersion and polymer-clay interaction on the viscoelastic response of PVME/clay and PEO/clay nanocomposites with varying degrees of dispersion and 6 polymer-clay interactions is analyzed. Polymer nanocomposites comprising highly ''~^^~^~^^^^^~ anisotropic layered silicates have attracted considerable attention because of their potential to lead to materials with exceptional thermal barrier and mechanical properties.…”

Section: Introductionmentioning

confidence: 99%

Analysis of nano‐reinforced layered plates via classical and refined two‐dimensional theories

Brischetto

Carrera

2012

Multidiscipline Modeling in Materials and Structures

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Purpose -The purpose of this paper is to consider the static analysis of nanocomposite plates. Nanocomposites consist of a small amount of nanoscale reinforcements which can have an observable effect on the macroscale properties of the composites. Design/methodology/approach -In the present study the reinforcements considered are non-spherical, high aspect ratio fillers, in particular nanometer-thin platelets (clays) and nanometer-diameter cylinders (carbon nanotubes, CNTs). These plates are considered simply supported with a bi-sinusoidal pressure applied at the top. These conditions allow the solving of the governing equations in a closed form. Four cases are investigated: a single layered plate with CNT reinforcements in elastomeric or thermoplastic polymers, a single layered plate with CNT reinforcements in a polymeric matrix embedding carbon fibers, a sandwich plate with external skins in aluminium alloy and an internal core in silicon foam filled with CNTs and a single layered plate with clay reinforcements in a polymeric matrix. A short review of the most important results in the literature is given to determine the elastic properties of the suggested nanocomposites which will be used in the proposed static analysis. The static response of the plates is obtained by using classical two-dimensional models such as classical lamination theory (CLT) and first order shear deformation theory (FSDT), and an advanced mixed model based on the Carrera Unified Formulation (CUF) which makes use of a layer-wise description for both displacement and transverse stress components. Findings -The paper has two aims: to demonstrate that the use of classical theories, originally developed for traditional plates, is inappropriate to investigate the static response of nanocomposite plates and to quantify the beneficial effect of the nanoreinforcements in terms of static response (displacements and stresses).Originality/value -In the literature these effects are usually given only in terms of elastic properties such as Young moduli, shear moduli and Poisson ratios, and not in terms of displacements and stresses.

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Role of polymer–clay interactions and nano-clay dispersion on the viscoelastic response of supercritical CO2 dispersed polyvinylmethylether (PVME)–Clay nanocomposites

Cited by 32 publications

References 35 publications

Solution Cross-Linked Natural Rubber (NR)/Clay Aerogel Composites

Solution Cross-Linked Natural Rubber (NR)/Clay Aerogel Composites

Use of supercritical CO₂ as a dispersing agent in the preparation of a polymer‐layered silicate nanocomposite

Analysis of nano‐reinforced layered plates via classical and refined two‐dimensional theories

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Role of polymer–clay interactions and nano-clay dispersion on the viscoelastic response of supercritical CO2 dispersed polyvinylmethylether (PVME)–Clay nanocomposites

Cited by 32 publications

References 35 publications

Solution Cross-Linked Natural Rubber (NR)/Clay Aerogel Composites

Solution Cross-Linked Natural Rubber (NR)/Clay Aerogel Composites

Use of supercritical CO2 as a dispersing agent in the preparation of a polymer‐layered silicate nanocomposite

Analysis of nano‐reinforced layered plates via classical and refined two‐dimensional theories

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Product

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Use of supercritical CO₂ as a dispersing agent in the preparation of a polymer‐layered silicate nanocomposite