Tran N H, Dennis G R, Milev A S, Kannangara G S K, Williams P, Wilson M A, Lamb R N
College of Science, Technology and Environment, University of Western Sydney, Locked Bag No. 1797, Penrith South DC, New South Wales 1797, Australia.
J Colloid Interface Sci. 2006 May 15;297(2):541-5. doi: 10.1016/j.jcis.2005.11.008. Epub 2005 Dec 15.
A method for formation of polymer-clay nanocomposites involves dispersion of the nanometer silicate layers of clays into a solvent, followed by dispersion into polymers. The dispersion of layered silicates within solvents affects the structure and properties of the nanocomposites. We report the dispersion of organically modified clays, used for formation of nanocomposites with organic polymers, within a range of alcohol solvents. Experiments involved stirring a mixture containing approximately 1 wt% of alkylammonium-modified clays in n-alcohols with general molecular structure RnOH, where n represents the number of carbons of alkyl chains, varying from 2 to 8. The clays precipitated from the dispersion when RnOH solvents with n<5 were used, however, they formed gels for solvents with n5. The increased dispersion was related to the decrease of polarity and hydrogen bonding force within solvents. X-ray diffraction for the dispersed clays indicated that the interlayer spaces (1.8 nm), formed by regular stacking of the silicate layers, expanded to a maximum of 3.0 nm after treatment with RnOH with n5. The interlayer expansion was due to the intercalation of n-alcohol molecules within the interlayer spaces. It is suggested that the alkyl chains of n-alcohols remain parallel to the silicate surface in the intercalate. Preliminary experiments on the influence of these alcohol solvents on the intercalation of polyol (polyether) are also reported.
一种制备聚合物-粘土纳米复合材料的方法包括将粘土的纳米硅酸盐层分散到溶剂中，然后再分散到聚合物中。层状硅酸盐在溶剂中的分散会影响纳米复合材料的结构和性能。我们报道了用于与有机聚合物形成纳米复合材料的有机改性粘土在一系列醇类溶剂中的分散情况。实验包括在具有通式RnOH的正醇中搅拌含有约1 wt%烷基铵改性粘土的混合物，其中n代表烷基链的碳原子数，范围从2到8。当使用n<5的RnOH溶剂时，粘土从分散体中沉淀出来，然而，对于n≥5的溶剂，它们形成了凝胶。分散性的提高与溶剂中极性和氢键力的降低有关。对分散粘土的X射线衍射表明，由硅酸盐层的规则堆叠形成的层间间距（1.8 nm）在用n≥5的RnOH处理后最大扩展到3.0 nm。层间膨胀是由于正醇分子插入层间空间所致。有人认为，正醇的烷基链在插层物中与硅酸盐表面保持平行。还报道了这些醇类溶剂对多元醇（聚醚）插层影响的初步实验。
