By a News Reporter-Staff News Editor at Science Letter -- New research on Acrylates is the subject of a report. According to news reporting from Sao Carlos, Brazil, by NewsRx journalists, research stated, "Montmorillonite/PMMA nanocomposites were obtained by in situ photopolymerization. Methyl methacrylate was photopolymerized in the presence of modified clay minerals using thioxanthone (TX) and ethyl 4-(dimethylamino) benzoate (EDB) as photoinitiating system."
The news correspondents obtained a quote from the research from the University of Sao Paulo, "The organomontmorillonites (SWy-1-C8-Mt and SWy-1-C16-Mt) were prepared by ion exchange of SW-1 Mt with octyltrimethylammonium bromide (C8) and hexyltrimethylammonium bromide (C16), respectively. X-ray diffraction indicated that clay/PMMA nanocomposites can have intercalated or exfoliated structures, or even a mixture of exfoliated and partially intercalated structure layers. The structure of each particular clay polymer nanocomposite (CPN) depends on the clay mineral loading and the solvent used for the preparation. The molecular weights of the SWy-1-C8/PMMA and SWy-1-C16/PMMA (1.0, 3.0 and 5.0%) obtained by photopolymerization in ethanol, were in the range of 1,000,000 to 3,000,000 D, and in acetonitrile the M-w values varied from 220,000 to 270,000 D. Photooxidative degradation of clay/PMMA nanocomposites has been investigated using size exclusion chromatography (SEC). Evidence was found that PMMA and CPN degrade by random chain scissions. The polydispersity increases after irradiation and the degradation rate coefficient for pure PMMA is up to 6 times larger than that for CPN. The effects of the clay mineral content, clay mineral type (clay mineral modified by surfactants with different lengths of alkyl chains) and solvent used for dispersion of organoclay on the photodegradation rate coefficients were also studied. The influence of these parameters on the photodegradation process was statistically evaluated using a two-level factorial design. The importance of the parameters was proved to follow the order: clay mineral content > clay mineral type > solvent. CPN with higher clay mineral loadings showed slower rates of oxidation. The clay mineral stabilizes the polymer against UV irradiation."
According to the news reporters, the research concluded: "SWy-1 clay mineral scatters and absorbs the incident light, decreasing the degradation rate of polymer present in the CPN."
For more information on this research see: Organomontmorillonite/poly(methyl methacrylate) nanocomposites prepared by in situ photopolymerization. Effect of the organoclay on the photooxidative degradation. Applied Clay Science, 2013;85():19-24. Applied Clay Science can be contacted at: Elsevier Science Bv, PO Box 211, 1000 Ae Amsterdam, Netherlands. (Elsevier - www.elsevier.com; Applied Clay Science - www.elsevier.com/wps/product/cws_home/503322)
Our news journalists report that additional information may be obtained by contacting S.R. Valandro, University of Sao Paulo, Inst Quim Sao Carlos, BR-13560970 Sao Carlos, SP, Brazil. Additional authors for this research include A.L. Poli, M.G. Neumann and C.C. Schmitt (see also Acrylates).
Keywords for this news article include: Brazil, Sao Carlos, South America, Methacrylates, Nanocomposite, Nanotechnology, Emerging Technologies
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