Increasing particle size of a synthetic smectite for polymer nanocomposites using a supercritical hydrothermal treatment
Increasing particle size of a synthetic smectite for polymer nanocomposites using a supercritical hydrothermal treatment
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DOI：
10.1016/j.jcis.2010.04.058
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发表时间：
2010-08-15
影响因子：
9.9
通讯作者：
Mizukami, Fujio
中科院分区：
文献类型：
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作者：
Ishii, Ryo;Teshima, Nobuyuki;Mizukami, Fujio
我们已经研究了超临界水热过程对合成蒙皂石粘土，硅镁石（ST）的结构和表面形态特性的影响，在粒度方面，为了提高合成蒙皂石作为透明粘土/聚合物纳米复合材料的无机填料的功能。在673 K和25 MPa下，在流动反应器系统中处理ST水悬浮液。结构表征表明，ST保留了层状结构的SiO 4四面体的聚合物片组成的处理后。经处理的ST具有71 nm的粒度，约为0.1重量%的初始ST（36 nm）的两倍。悬浮液，使用0.085g s（-1）的流速的操作条件。扫描电镜观察发现，一个扩大的颗粒形成的凝聚力的聚集体，这表明在颗粒的尺寸增加是由ST的微晶或初级颗粒的凝聚力。处理后的ST随后用于制备纳米复合材料与羧甲基纤维素钠盐（CMC Na），以评估超临界处理的效果。经处理的ST纳米复合材料膜保持其透明度，这与原始ST纳米复合材料膜非常相似。此外，具有40至90重量%的高CMC Na比率的纳米复合膜，显示出改善的氧气阻隔性能相比，原来的ST。曲折模型显示，这种改善主要是由于颗粒尺寸的增加。因此，超临界处理成功地带来了ST颗粒的生长，导致粘土/聚合物纳米复合材料的功能性合成粘土的发展。(C)2010年爱思唯尔公司All rights reserved.
We have studied the effect of a supercritical hydrothermal process on the structural and surface morphological properties of synthetic smectite clay, stevensite (ST), in terms of the particle size, in order to enhance the functionality of the synthetic smectites as an inorganic filler for transparent clay/polymer nanocomposites. The ST aqueous suspensions were treated in a flow reactor system at 673 K and 25 MPa. The structural characterizations revealed that the ST retained a layered structure composed of polymeric sheets of SiO4 tetrahedra after the treatment. The treated ST possessed a particle size of 71 nm, approximately twice that of the original ST (36 nm) for the 0.1 wt.% suspension using an operation condition at a flow rate of 0.085 g s(-1). SEM observation revealed that an enlarged particle was formed from cohesive aggregates, suggesting that the increase in size of the particles was caused by the cohesion of the microcrystallites or primary particles of ST. The treated ST was subsequently used to prepare nanocomposites with carboxymethylcellulose sodium salt (CMC Na) to evaluate the effect of the supercritical treatment. The treated ST nanocomposite films retained their transparency which is very similar to the original ST nanocomposite films. Furthermore, the nanocomposite films, which had a high CMC Na ratio ranging from 40 to 90 wt.%, showed improved oxygen barrier properties when compared with those of original ST. The tortuous model revealed that this improvement was mainly due to the increase of the particle size. Consequently, the supercritical treatment successfully brought about the growth of the ST particles, leading to the development of functional synthetic clays for clay/polymer nanocomposites. (C) 2010 Elsevier Inc. All rights reserved.