Studies in Gelation and Film Formation. II. Studies in Clay Films.

Hauser, Ernst A.; Beau, D. S. Le

doi:10.1021/j150395a007

Cited by 15 publications

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“…The first clay paper was shaped from bentonite by Hauser in 1938. [3,4] It was not highly transparent and not prepared with the aim of giving it a high gas-barrier property. Claybased artificial nacre had been studied, [5][6][7][8] but it was not highly transparent.…”

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Flexible Transparent Clay Films with Heat‐Resistant and High Gas‐Barrier Properties

2007

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Few thin films, which possess flexibility, transparency, gas shielding, thermal stability, and mechanical strength, have been reported so far, although such materials have a wide range of applications and are in demand for optoelectronic devices. Glass is superior in heat-durability, transparency, and gas-barrier properties and, therefore, normally used as a display material; however, it is inferior in flexibility, relatively heavy, and difficult to make very thin. On the other hand, plastic is superior in flexibility, formability, and transparency; however, its dimensional stability, that is, its low thermal expansion rate and gas shielding are not good enough. For example, for a typical plastic film, such as polyethylene terephthalate (PET), the glass-transition temperature and oxygen permeability are 78°C, [1] and 40 cm 3 20 lm m -2 day -1 atm -1(1 atm ≈ 101 325 Pa), [2] respectively. We have succeeded in preparing flexible thin films having all of the above-mentioned properties (in detail, oxygen permeability less than 0.1 cm 3 20 lm m -2 day -1 atm -1 , over 90 % of total visible-light transmittance, which is comparable to conventional transparent plastic films, heat-durability up to 350°C, and mechanical strength enough to be handled) by casting aqueous dispersions of a synthetic hydrophilic clay mixed with a small amount of water-soluble organic polymer. X-ray diffraction (XRD) patterns suggest a unique close-packed lamellar structure for the film, which may bring superior heat durability. The developed films are promising for use in a wide variety of optoelectronic applications. The first clay paper was shaped from bentonite by Hauser in 1938. [3,4] It was not highly transparent and not prepared with the aim of giving it a high gas-barrier property. Claybased artificial nacre had been studied, [5][6][7][8] but it was not highly transparent. Polymer-clay nanocomposite materials have been actively studied since the 1970s. [9][10][11][12][13][14][15][16][17] Most of the composites are mainly composed of plastics, and clays are only added as minor components at less than 10 wt %.[10] Although the addition improves the mechanical strength, [11] gasbarrier properties, [12] flammability reduction, [13] and dimensional stability, [14] these performances are still low. Chaiko [15,16] has developed a new and cost-effective method of producing polymer-clay nanocomposites using almost any nonpolar, commercial polymer. The surfactant-treated clays can greatly enhance a product's thermal stability, improve stiffness and strength, and increase gas-barrier performance. The oxygen-barrier properties of these nanocomposite films are over 2 000 times better than Nylon-6. Haraguchi et al. [17] prepared stretchy clay composites with high optical clarity and flexibility; however they are not highly heat durable because the clay content is limited to 30 wt %. Triantafyllidis et al. [12] prepared an epoxy-clay film composite with a high oxygen-barrier property. The film contains a higher loading of clay but is yellowish and not ...

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Flexible Transparent Clay Films with Heat‐Resistant and High Gas‐Barrier Properties

2007

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“…Completely self-supporting clay membranes were first described by Hauser and Le Beau. 19 They observed that when sols of such substances as sodium and hydrogen bentonite were converted to gels and then completely desiccated, long, interlacing filaments resulted which were tied together by tridimensional crosslinkages, producing a coherent, self-supporting network. The technique of Hauser and Le Beaulg has been employed by Marshall and co-workers2",21 to make mineral membranes 0.1 to 0.5 mm.…”

Section: (A) Inorganic Membranesmentioning

confidence: 99%

The preparation of membrances

Carnell

Cassidy

1961

J. Polym. Sci.

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A membrane is defined as a solid, porous sheet which, when placed between two phases, may allow the passage of small particles but hinder or prevent the passage of large particles. With this definition as a basis a review is given of methods employed to prepare membranes, with special emphasis on the preparation of organic membranes. Directions are then given for the preparation of thin, uniform membranes 100 to 1500 A. or thicker. Membranes of 500 or 600 A., in thickness with a variation of less than 25 A. across a section as large as 3.5 cm. sq. are described, together with evidence for physical and chemical stability. These are prepared from pyroxylin. Thin membranes were also prepared from Formvar 15/95 E (polyvinylformal from Shawinigan Resins Corp.) and VYDR, blend 7 (a high molecular weight vinylchloride‐acetate resin containing approximately 96% vinylchloride and 4% vinylacetate, from Bakelite). No success was achieved with DYNH (a polythylene from Bakelite); and polyisobutylmethacrylate (Monomer‐Polymer).

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“…A purified, monodisperse bentonite sol of 1 per cent concentration, produced by supercentrifuging and containing particles ranging in apparent spherical diameter between 15 and 50 mp, proved particularly suitable (42) for studies of stream double refraction, because such a sol is quite clear to the eye, has practically the same viscosity and surface tension as water, and exhibits pronounced birefringence a t extremely low rates of flow and for any temperature up to the boiling point of water (44). This is actually the case, but permanent effects can only be expected if truly colloidal clays are used, becauqe only then can one eliminate sedimentation of the disperse phase (3).…”

Section: F Rheopexymentioning

confidence: 99%

Colloid Chemistry of Clays.

Hauser¹

1945

Chem. Rev.

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Studies in Gelation and Film Formation. II. Studies in Clay Films.

Cited by 15 publications

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Flexible Transparent Clay Films with Heat‐Resistant and High Gas‐Barrier Properties

Flexible Transparent Clay Films with Heat‐Resistant and High Gas‐Barrier Properties

The preparation of membrances

Colloid Chemistry of Clays.

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