Clay-chitosan nanobrick walls: completely renewable gas barrier and flame-retardant nanocoatings.
| Autor: | Laufer G; Department of Mechanical Engineering, Texas A&M University, College Station, Texas 77843, USA., Kirkland C, Cain AA, Grunlan JC |
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| Jazyk: | angličtina |
| Zdroj: | ACS applied materials & interfaces [ACS Appl Mater Interfaces] 2012 Mar; Vol. 4 (3), pp. 1643-9. Date of Electronic Publication: 2012 Mar 01. |
| DOI: | 10.1021/am2017915 |
| Abstrakt: | Thin films prepared via a layer-by-layer (LbL) assembly of renewable materials exhibit exceptional oxygen barrier and flame-retardant properties. Positively charged chitosan (CH), at two different pH levels (pH 3 and pH 6), was paired with anionic montmorillonite (MMT) clay nanoplatelets. Thin-film assemblies prepared with CH at high pH are thicker, because if the low polymer charge density. A 30-bilayer (CH pH 6-MMT) nanocoating (~100 nm thick) reduces the oxygen permeability of a 0.5-mm-thick polylactic acid film by four orders of magnitude. This same coating system completely stops the melting of a flexible polyurethane foam, when exposed to direct flame from a butane torch, with just 10 bilayers (~30 nm thick). Cone calorimetry confirms that this coated foam exhibited a reduced peak heat-release rate, by as much as 52%, relative to the uncoated control. These environmentally benign nanocoatings could prove beneficial for new types of food packaging or a replacement for environmentally persistent antiflammable compounds. (© 2012 American Chemical Society) |
| Databáze: | MEDLINE |
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