CLAY POLYMER NANOCOMPOSITES FORMED FROM ACIDIC DERIVATIVES OF MONTMORILLONITE AND AN EPOXY-RESIN
CLAY POLYMER NANOCOMPOSITES FORMED FROM ACIDIC DERIVATIVES OF MONTMORILLONITE AND AN EPOXY-RESIN
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DOI：
10.1021/cm00040a022
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发表时间：
1994-04-01
影响因子：
8.6
通讯作者：
PINNAVAIA, TJ
中科院分区：
文献类型：
--
作者：
WANG, MS;PINNAVAIA, TJ
A new type of clay-polymer nanocomposite has been prepared by the spontaneous self-polymerization of an epoxy resin, the diglycidyl ether of bisphenol A (DGEBA), and the concomitant delamination (exfoliation) of acidic forms of montmorillonite at elevated temperatures. The epoxide polymerization-clay delamination temperature (PDT) was dependent on the heating rate and the nature of the clay-exchange cation. H+, NH4+, and acidic onium ions of the type [H3N(CH2)n-1COOH]+, [H3N(CH2)nNH2]+, [H3N(CH2)nNH3]2+, and [H3N-(CH2)n-1CH3]+ (n = 6 and 12) facilitated the polymerization-delamination process over the temperature range 198-287-degrees-C. In general, the PDT increased with decreasing cation acidity and decreasing basal spacing of the clay. Evidence for nanocomposite formation was provided in part by a dramatic liquid-to-powder transformation of the clay-epoxide mixture upon formation of the polyether. The delamination of montmorillonite into 9.6-angstrom layers was further confirmed by transmission electron micrographs, which revealed interlayer separations up to approximately 2000 angstrom and by the absence of clay reflections in the X-ray powder diffraction patterns. Differential scanning calorimetry studies of a polyether nanocomposite containing 5 wt % [H3N(CH2)11COOH]+- montmorillonite indicated the heat of reaction and activation energy for the organoclay-catalyzed polymerization reaction to be 228 and 108 kJ/mol, respectively.
