通过小角中子和 X 射线散射研究有无添加剂的硅酸钙水合物凝胶中液滴的微观结构变化。

Microstructural changes of globules in calcium-silicate-hydrate gels with and without additives determined by small-angle neutron and X-ray scattering.

机构信息

Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.

出版信息

J Colloid Interface Sci. 2013 May 15;398:67-73. doi: 10.1016/j.jcis.2013.01.065. Epub 2013 Feb 18.

DOI:10.1016/j.jcis.2013.01.065

Abstract

The microstructure of calcium-silicate-hydrate (C-S-H) gel, a major hydrated phase of Ordinary Portland Cement, with and without polycarboxylic ether (PCE) additives is investigated by combined analyses of small-angle X-ray scattering (SAXS) and small-angle neutron scattering (SANS) data. The results show that these comb-shaped polymers tend to increase the size of the disk-like globules but have little influence on the thickness of the water and calcium silicate layers within the globules. As a result, the fractal packing of the globules becomes more open in the range of a few hundred nanometers, in the sense that the mass fractal dimension diminishes, since the PCE adsorption on the globules increases the repulsive force between and polydispersity of the C-S-H units. Moreover, scanning electron microscope (SEM) study of the synthesized C-S-H gels in the micrometer range shows that the PCEs depress the formation of fibrils while enhancing the foil-like morphology.

摘要

通过小角 X 射线散射（SAXS）和小角中子散射（SANS）数据的综合分析，研究了普通波特兰水泥主要水合相硅酸钙水合物（C-S-H）凝胶的微观结构，有无聚羧酸醚（PCE）添加剂。结果表明，这些梳状聚合物往往会增加盘状小球的尺寸，但对小球内水和硅酸钙层的厚度影响不大。因此，在几百纳米的范围内，小球的分形堆积变得更加开放，因为 PCE 在小球上的吸附增加了 C-S-H 单元之间的排斥力和多分散性。此外，对合成的 C-S-H 凝胶在微米范围内的扫描电子显微镜（SEM）研究表明，PCE 抑制了纤维的形成，同时增强了箔状形态。