Highly Concentrated, Intercalated Silicate Nanocomposites:  Synthesis and Characterization

Zerda, Adam S.; Caskey, Terrence C.; Lesser, Alan J.

doi:10.1021/ma0213450

Cited by 76 publications

(54 citation statements)

References 21 publications

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“…However, Zerda and coworkers 11 were able to incorporate large concentrations of organically modified layered silicates into poly(methyl methacrylate) (PMMA) through the use of supercritical CO 2 as a reaction medium. In this work, we were able to incorporate only 10 wt % of laponite into coating compositions while maintaining good dispersion and transparency.…”

Section: Effect Of Clay Content On the Photopolymerization Kinetics Omentioning

confidence: 99%

“…10 The morphologies of the systems obtained can usually be classified as either exfoliated or intercalated with some degree of aggregation. 11 Melt processing consists of blending a molten thermoplastic polymer with clay at high temperature and high shear, which can sometimes lead to thermodegradation during processing. 12 This may be overcome by using solution intercalation, which consists of swelling the clay in a solvent followed by addition of a solution of the polymer dissolved in the same solvent.…”

Section: Introductionmentioning

confidence: 99%

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Synthetic clay nanocomposite‐based coatings prepared by UV‐cure photopolymerization

Shemper

Morizur

Alirol

et al. 2004

J of Applied Polymer Sci

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ABSTRACT:The effect of synthetic clay on the photopolymerization kinetics and coating properties of methyl ␣-hydroxymethylacrylate (MHMA) systems in the presence of novel hydroxylated dimethacrylate crosslinkers is reported. In the presence of clay earlier onset of autoacceleration was observed, high rates of polymerization were achieved, and high final overall conversions were reached. Higher rates and increase in conversions were also observed as the clay content increased in the medium. To increase compatibility between clay and polymer matrix the use of Jeffamines as polymer/clay compatibilizers, based on ion-dipole interactions between ethylene oxide units and clay ions, was also investigated. Nanocomposite-based films by photopolymerization of the mixtures coated on glass microscope slides were prepared and evaluated using X-ray and TEM. The absence of Bragg diffraction peaks in all nanocomposite films indicated loss of organization of the clay layers and formation of well-dispersed, exfoliated systems was confirmed by TEM.

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Section: Effect Of Clay Content On the Photopolymerization Kinetics Omentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Synthetic clay nanocomposite‐based coatings prepared by UV‐cure photopolymerization

Shemper

Morizur

Alirol

et al. 2004

J of Applied Polymer Sci

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“…Recently, an in-situ polymerization method used sc CO 2 as a processing aid to achieve a uniform reinforcement distribution in a polymer/clay composite at high clay loading (∼40 wt %). 13 Intercalation of unreactive small molecules into layered clay in the presence of sc CO 2 has also been …”

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confidence: 99%

Supercritical CO₂-Mediated Intercalation of PEO in Clay

Zhao

Samulski

2003

Macromolecules

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Introduction. Polymer/clay nanocomposites prepared by a variety of methods that embed these inorganic nanolayers to a polymer host have been actively studied in recent years as these materials exhibit dramatic, concurrent improvements in many properties. 1 Typical preparation methods include in-situ polymerization, solution intercalation, and melt intercalation, among which solution intercalation has been known for over a century and has proved to be one of the most successful methods of incorporating delaminated clay into polymers. 2 Many polymers have been intercalated into clay via this method: Examples include water-soluble polymers such as poly(ethylene oxide) and poly(vinyl alcohol) 3,4 and organic solventsoluble polymers such as high-density polyethylene, 5 poly(L-lactide), 6 etc. Despite many laboratory successes with solution intercalation, its application on an industrial scale is still hindered by two major problems: (1) involvement of large quantities of aqueous/organic solvent; (2) a limited number of solvent/polymer pairs available for polymer dissolution and subsequent intercalation.During the past decade, supercritical carbon dioxide (sc CO 2 ) has attracted a great deal of attention as an "environmentally benign, inexpensive, and nonflammable alternative" solvent for polymer synthesis and processing. 7,8 The low viscosity, near-zero surface tension, relative chemical inertness, and high diffusivity of sc CO 2 results in negligible competitive adsorption with guest molecules on the host substrate and therefore facilitates solute transfer relative to normal solvents. Furthermore, since CO 2 is a gas at ambient conditions, the tedious drying procedure associated with conventional liquid solvents is circumvented, and the product is free of residual solvent upon depressurization.These unique properties of sc CO 2 have been exploited to prepare polymer blends. [9][10][11][12] The usual method employs sc CO 2 as a swelling agent to facilitate the diffusion of a guest monomer into a CO 2 -swollen polymer matrix. Subsequent polymerization develops a blend of submicron phase-separated polymers. Recently, an in-situ polymerization method used sc CO 2 as a processing aid to achieve a uniform reinforcement distribution in a polymer/clay composite at high clay loading (∼40 wt %). 13 Intercalation of unreactive small molecules into layered clay in the presence of sc CO 2 has also been

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“…Zerda et al [73] used scCO2 as a low viscosity solvent in the in-situ polymerization of poly(methyl methacrylate) (PMMA). The primary purpose of the scCO2 was to allow methyl methacrylate monomers to readily diffuse and homogeneously disperse within the gallery spacings of the silicate layers.…”

Section: Supercritical Carbon Dioxide In Anocomposite Compoundingmentioning

confidence: 99%

Improving the exfoliation of layered silicate in a poly(ethylene terephthalate) matrix using supercritical carbon dioxide

Samaniuk

Litchfield

Baird

2009

Polymer Engineering & Sci

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Supercritical carbon dioxide (scCO2) was used as a processing aid to improve the level of exfoliation achievable in a PET-layered silicate nanocomposite produced from melt compounding. Layered silicate and scCO2 were allowed to mix for a period of time before being released into the second stage of a single screw extruder. The rapid expansion forced silicate particles into a modified hopper containing neat PET pellets.The mixture of layered silicate and PET was immediately melt mixed in a single screw extruder, cooled in a water bath and pelletized. Two sets of samples each containing layered silicate with different surface chemistries were produced with this method at 1, 3 and 5 wt% silicate. For comparison, samples of the same weight fraction and type of silicate were produced from a traditional melt compounding method. Wide angle x-ray diffraction (WAXD), mechanical testing and rheological analysis were used in order to characterize the silicate morphology, the composite mechanical properties and the relative amount of degradation between the various samples. Results show that scCO2 processed samples contain a higher degree of layered silicate exfoliation than samples produced with traditional melt compounding. Mechanical property improvements are shown to be dependent on the type of silicate surface modification employed. Finally, degradation of the PET matrix appears to be far less extensive in the scCO2 processed samples as shown from rheological data.iii Acknowledgements

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Highly Concentrated, Intercalated Silicate Nanocomposites: Synthesis and Characterization

Cited by 76 publications

References 21 publications

Synthetic clay nanocomposite‐based coatings prepared by UV‐cure photopolymerization

Synthetic clay nanocomposite‐based coatings prepared by UV‐cure photopolymerization

Supercritical CO₂-Mediated Intercalation of PEO in Clay

Improving the exfoliation of layered silicate in a poly(ethylene terephthalate) matrix using supercritical carbon dioxide

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Highly Concentrated, Intercalated Silicate Nanocomposites: Synthesis and Characterization

Cited by 76 publications

References 21 publications

Synthetic clay nanocomposite‐based coatings prepared by UV‐cure photopolymerization

Synthetic clay nanocomposite‐based coatings prepared by UV‐cure photopolymerization

Supercritical CO2-Mediated Intercalation of PEO in Clay

Improving the exfoliation of layered silicate in a poly(ethylene terephthalate) matrix using supercritical carbon dioxide

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Supercritical CO₂-Mediated Intercalation of PEO in Clay