Supercritical CO2 dispersion of nano-clays and clay/polymer nanocomposites

Horsch, Steven; Serhatkulu, Gulay K.; Gulari, Esin; Kannan, Rangaramanujam M.

doi:10.1016/j.polymer.2006.08.048

Cited by 99 publications

(97 citation statements)

References 38 publications

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“…17 In general, this unique solvent afforded rearrangement of the surfactant and greater organic coverage over the silicate surface, which brought about either basal expansion or partial collapse depending on the original surfactant arrangement in the galleries. With rapid depressurization of the clay suspension in scCO 2 , a small but further increase in basal spacing was detected, though the work of Horsch et al 21 suggested instead that the particles were fractured. In the studies of this article, these rapidly depressurized scCO 2 -treated organoclays are simply referred to as pretreated and the species included in the study is denoted as s-C20A.…”

Section: Resultsmentioning

confidence: 98%

Influence of supercritical CO₂ on the interactions between maleated polypropylene and alkyl‐ammonium organoclay

Liu

Thompson

Balogh

et al. 2010

J of Applied Polymer Sci

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Supercritical carbon dioxide (scCO 2 ) has been proposed as an effective exfoliating agent for the preparation of polymer-layered silicate nanocomposites, though there is limited fundamental understanding of this mechanism. This study looks at the interactions of this unique green solvent with three maleated polypropylenes of varying anhydride content and molecular size with an alkyl-ammonium organoclay. Mixtures of compatibilizers and organoclay were melt-annealed in a high pressure batch vessel at 200 C and subjected to either a blanket of nitrogen or scCO 2 at a pressure of 9.7 MPa. The structures and properties of these melt-annealed mixtures were characterized by X-ray diffraction, transmission electron microscopy, Fourier Transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, differential scanning calorimetry, and contact angle measurement. The results indicate that the plasticizing influence of scCO 2 aided intercalation and exfoliation for intercalants of moderate molecular size and anhydride content which would otherwise have limited diffusion into the clay galleries.

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Section: Resultsmentioning

confidence: 98%

Influence of supercritical CO₂ on the interactions between maleated polypropylene and alkyl‐ammonium organoclay

Liu

Thompson

Balogh

et al. 2010

J of Applied Polymer Sci

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“…Understanding the exfoliation of clay platelets in a polymer matrix is very important in designing nano-clay composites with the desirable thermal and mechanical characteristics [1][2][3][4][5][6][7][8][9] such as reducing gas permeability and flame propagation and enhancing strength with respect to tensile response. Controlling the distribution of clay platelets in appropriate polymer matrix is crucial to achieve such thermomechanical characteristics.…”

Section: Introductionmentioning

confidence: 99%

Exfoliation of a stack of platelets and intercalation of polymer chains: Effects of molecular weight, entanglement, and interaction with the polymer matrix

Pandey

Farmer

2008

J Polym Sci B Polym Phys

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Exfoliation of a stack of sheets (a model for clay platelets) in a dynamic matrix of polymer chains is investigated by a computer simulation model. How the interplay between the thermodynamics (interaction-driven) and conformational (structural constraints) entropy affects the exfoliation of sheets is the subject of this study. A stack of four sheets with a small initial interlayer distance constitutes the layer on a discrete lattice. The layered platelets are immersed in a matrix represented by the mobile polymer chains which occupy a fraction (concentration) of the lattice sites. Both sheets and chains are modeled by the bond-fluctuation mechanism and execute their stochastic motion via Metropolis algorithm. An attractive and a repulsive interaction between the polymer matrix and platelets are considered. Exfoliation of the sheets is examined by varying the molecular weight of the polymer chains forming a dynamic network matrix with various degrees of entanglements. At lowmolecular weight of the polymer, exfoliation is achieved with repulsive interaction and the exfoliation is suppressed with attractive matrix as sheets stick together via polymer mediated interaction introduced by intercalated polymer chains. Increasing the molecular weight of the polymer matrix suppresses the exfoliation of sheets primarily due to enhanced entanglement-at high-molecular weight (with the radius of gyration of polymer chains larger than the characteristic linear dimension of the platelets), the stacked (layered) morphology is arrested via entropic trapping and exfoliation ceases to occur.

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“…Since MMT consists of a triple-layer sandwich structure, hence its dispersion mechanism in rubber is different from carbon black and silica which have a spherical shape. 28 As reported in literature [28][29][30][31][32] intercalation and exfoliation morphologies are used to characterise the clay layer dispersion in clay/polymer nanocomposites. The latter morphology is more desirable due to its high surface area, which is important in rubber reinforcement.…”

Section: Introductionmentioning

confidence: 99%

The potential of kaolin as a reinforcing filler for rubber composites with new sulfur cure systems

Sheikh

Yin

Ansarifar

et al. 2017

Journal of Reinforced Plastics and Composites

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The effect of a large amount of kaolin (China clay) on the viscosity, cure, hardness, Young’s modulus, tensile strength, elongation at break, stored energy density at break, tear energy and compression set resistance of some sulfur-cured natural rubber, polybutadiene rubber and ethylene-propylene-diene rubber composites was investigated. The kaolin surface had been pre-treated with 3-mercaptopropyltrimethoxysilane to improve its dispersion in the rubbers. For natural rubber, the hardness and Young’s modulus improved, tensile strength and tear energy were unchanged and the remaining properties deteriorated when kaolin was added. The viscosity increased and the scorch and optimum cure times decreased whilst the cure rate rose with kaolin. For polybutadiene rubber and ethylene-propylene-diene rubber, with the exception of the compression set resistance, all the properties including the viscosity gained from the kaolin. The kaolin was found to be extending or non-reinforcing filler for natural rubber, and highly reinforcing for polybutadiene rubber and EPDM. In addition, the scorch and optimum cure times and cure rate of polybutadiene rubber benefitted, whereas with the exception of the scorch time, the optimum cure time and cure rate of ethylene-propylene-diene rubber were adversely affected by kaolin.

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Supercritical CO2 dispersion of nano-clays and clay/polymer nanocomposites

Cited by 99 publications

References 38 publications

Influence of supercritical CO₂ on the interactions between maleated polypropylene and alkyl‐ammonium organoclay

Influence of supercritical CO₂ on the interactions between maleated polypropylene and alkyl‐ammonium organoclay

Exfoliation of a stack of platelets and intercalation of polymer chains: Effects of molecular weight, entanglement, and interaction with the polymer matrix

The potential of kaolin as a reinforcing filler for rubber composites with new sulfur cure systems

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Supercritical CO2 dispersion of nano-clays and clay/polymer nanocomposites

Cited by 99 publications

References 38 publications

Influence of supercritical CO2 on the interactions between maleated polypropylene and alkyl‐ammonium organoclay

Influence of supercritical CO2 on the interactions between maleated polypropylene and alkyl‐ammonium organoclay

Exfoliation of a stack of platelets and intercalation of polymer chains: Effects of molecular weight, entanglement, and interaction with the polymer matrix

The potential of kaolin as a reinforcing filler for rubber composites with new sulfur cure systems

Contact Info

Product

Resources

About

Influence of supercritical CO₂ on the interactions between maleated polypropylene and alkyl‐ammonium organoclay

Influence of supercritical CO₂ on the interactions between maleated polypropylene and alkyl‐ammonium organoclay