A New Preparation Method of Inorganic Ultrafine Particles by Using Water-borne Associating Polymer

烷基改性聚乙烯醇(PVA)是一类在水中缔合并形成缔合簇合物的水性缔合聚合物。在本研究中，疏水改性的聚乙烯醇只在主链的一端有一个十二基，用于制备氧化锆等无机微粒。制备超细粒子的基本方案是形成复合团簇，该团簇由烷基修饰的PVAS团簇和团簇中疏水的锆盐(醋酸锆)组成。为了形成这样的复合簇合物，将烷基修饰的PVA水溶液与醋酸锆-醋酸溶液混合，并温和搅拌几个小时。在这个温和的搅拌过程中，醋酸锆有望进入PVA团簇的内部。将混合物烘干和焙烧，以便从醋酸锆中生成氧化锆细小颗粒。研究了制备条件对粒子形貌和一次、二次粒子直径的影响，采用疏水改性的PVA制备了一次结构的氧化锆微粒子。我们的预期和观察到的不同之处在于，使用对照聚合物(即普通PVA)也可以获得细小的颗粒(一级结构)，尽管颗粒的尺寸比使用疏水性改性的PVA制备的颗粒大。

Alkyl modified poly(vinyl alcohols) (PVAs) are classified as water-borne associating polymers which associate in water and form associating clusters. In this study, hydrophobically-modified polyvinyl alcohols, in which a dodecyl group is located only at one end of the backbone, were used for preparing inorganic fine particles such as zirconia. The basic scheme for preparing fine particles is formation of composite clusters which consist of the alkyl modified PVAs clusters and a hydrophobic zirconium salt (zirconium acetate) in the clusters. For forming such composite clusters, an alkyl modified PVA aqueous solution was mixed with a zirconium acetate-acetic acid solution, and the mixture was stirred mildly for several hours. During this mild stirring, zirconium acetate is expected to enter the inside of the PVA cluster. The mixture was dried and calcined in order to form zirconia fine particles from zirconium acetate. The effects of preparation conditions on the particles morphology and the diameters of primary and secondary particles were investigated.By applying hydrophobically-modified PVAs, zirconia fine particles as a primary structure were obtained. Difference between what we expected and what was observed is that fine particles (primary structure) were also obtained using the control polymer (i.e., an ordinary PVA), although the size of the particles was larger than that of the particles prepared using the hydrophobically-modified PVA.