机制砂石粉表面修饰及其性能研究

目的提供一种以化学接枝法替代传统物理吸附法的理论思路,改善机制砂石粉在水泥中的和易性。方法先将机制砂石粉与硅烷偶联剂γ-(甲基丙烯酰氧)丙基三甲氧基硅烷(MPS)进行羟基反应,使其表面带有C=C化学官能团,再与丙烯酸(AA)、2-甲基丙烯酸聚乙二醇单甲醚酯(MPEG)共聚。采用傅里叶变换红外光谱(FT-IR)、场发射扫描电镜、热重曲线、X射线衍射等分析手段表征机制砂石粉的改性效果和表面结构。将合成的复合材料以不同的比例掺杂于水泥中,通过净浆实验研究合成材料与水泥的流动适应性和流动保持性。结果生成的高分子化合物以化学键的方式链接在机制砂石粉表面。与未修饰的机制砂石粉相比,修饰后的机制砂石粉的可流动性及流动保持性有较大改善。结论经高分子化合物改性后,机制砂石粉在水泥中的流动适应性和流动保持性有显著提高。该思路合成的新型材料对水泥基复合材料的理论研究有一定的现实意义。

Preparation and Characterization of Artificial Sand Modified by Polymers

Objective To provide a theoretical chemical grafting method for substitution of the traditional physical adsorption method, and improve the workability of the artificial sand microfines in the cement. Methods After reaction with 3-methacrylo-xypropyltrimethoxysilane and graft with poly (acrylic acid) and poly (methoxy poly (ethylene glycols) methacrylate), the artificial sand was turned into the new artificial sand particles. Structure properties of the modified artificial sand particles were investigated by scanning electron microscopy (SEM), fourier transform infrared spectra (FT-IR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The synthesized composites were mixed into cement by different proportions and the fluidity and stability of the composited material with cement was investigated by neat paste test. Results The fluidity and stability of the surface-modified artificial sand microfines / cement paste was better than those of pristine artificial sand microfines / cement paste. Conclusion The results revealed that the surface-modified artificial sand microfines can significantly improve the workability and the durability of concrete. This study had certainly practical significance in theoretical study of cement-based composites.