A New Pigment Type: Colored Diblock Copolymer-Mica Composites

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• 作者：Leï ; la Ghannam ; Hé ; lè ; ne Garay ; Martin E. R. Shanahan ; Jeanne Fran&ccedil ; ois ; and Laurent Billon
• 刊名：Chemistry of Materials
• 出版年：2005
• 出版时间：July 26, 2005
• 年：2005
• 卷：17
• 期：15
• 页码：3837 - 3843
• 全文大小：315K
• 年卷期：v.17,no.15(July 26, 2005)
• ISSN：1520-5002

文摘

New mica-polymer composite pigments have been prepared and characterized. The pigments areprepared from mica surfaces by block copolymerization of butyl acrylate (BA) and a mixture of styrene(S) and a modified alizarin (A; dye). This is performed after physical adsorption of a radical initiatorwith a cationic group. Some of the copolymer was desorbed from the surface and characterized by ¹HNMR, size exclusion chromatography, and UV-visible spectroscopy. This desorbed copolymer fractionhad a number-average molecular weight of 140 000 g·mol^-1 with chemical compositions of 16% and84% M, respectively, of poly(butyl acrylate) (PBA) and poly(styrene-alizarin) [P(S-A)]. In addition, ithad a yellow coloration when in the bulk form. The remaining mica composites were characterized byFourier transform infrared spectroscopy, thermogravimetric analysis, and X-ray diffraction. It was foundthat 0.07 molecules of block copolymer per nm² of mica remained adsorbed on the mica surface. Thisleads to a surprising pink color, which may be explained by the basicity of the mica surface due to thepH-color-sensitive character of the alizarin dye.