核壳结构球形分散剂可控组装及分散模型研究

This project is to design a kind of spherical dispersant molecule with core-shell structure for dispersing study of cement particles. The spherical kernel belongs to neutral or weakly lipophilic structure, the spherical shell contains many hydrophilic groups. Spherical kernel is mainly to provide steric-hindrance, the shell is composed of a large number of carboxylic acid groups, sulfonic acid groups, hydroxyl groups, ester groups, oxygen-vinyl groups, which provide "anchor" groups with the cement particles, so this kind of spherical dispersant molecule can form strongly dispersion and water-reducing effect on the cement particles. The "roll-effect" formed by the spherical morphology of dispersant can avoid intermolecular "twining-effect", so that the dispersibility and dispersing-stability can be sustained and stable present. The controlling technology of the assembly-sequences of the hydrophilic groups on spherical surface, the preparing technology of spherical kernel and the assembly mechanism of the spherical kernel with hydrophilic groups were studied. These helped to construct controllable assembly model of the core-shell structure. Targeting adsorption technology would be grasped by studying the adsorption mechanism between the hydrophilic groups with cement particles. The "rolling dispersion model" of the spherical dispersant were established by a comprehensive analysis of the above content."Roll" dispersion model is the third model following the "electrostatic repulsion" and "steric hindrance" dispersion model, this new basic dispersion theory will be able to provide a new idea for dispersant research.

项目针对水泥颗粒的分散问题而设计一种核壳结构球形分散剂分子。球形内核为中性或弱亲油性结构，球形外壳为亲水性基团。球形内核主要提供空间位阻作用，外壳由大量的羧酸基、磺酸基、羟基、酯基、氧乙烯基构成，提供与水泥颗粒的"锚固"基团，从而对水泥颗粒形成强烈的分散减水作用。利用球形分子形貌形成的"滚珠"效应避免分散剂分子间的"缠绕桥接"，从而使得分散性和分散稳定性得以持续稳定存在。通过研究表面外壳基团组装序列的控制技术、目标球形内核的制备技术、亲水性基团与球形内核的组装机制来建立核壳结构球形分散剂的表面结构可控组装模型；通过研究功能基团与胶凝材料颗粒之间的作用机理来掌握分散剂与胶凝材料颗粒之间的靶向作用控制技术。综合以上研究成果最终建立球形分散剂的"滚动"分散模型。"滚动"分散模型是继"静电排斥"分散模型和"空间位阻"分散模型后的第三种分散模型，这种新的分散基础理论为分散剂的研究提供了一种新思路。

本项目在传统梳形高分子分散剂结构基础上，从空间位阻分散机理入手，通过引进球形高分子来消除传统梳形高分子长侧链的“缠绕”，从而获得了系列新型结构高聚物分散剂。项目首先在传统梳形羧酸分散剂分子结构基础上进行改性，获得改性聚合物分散剂BS-1。在此基础上应用市场定型成熟球形高分子聚乙烯亚胺（HPEI）改性梳形聚合物结构，利用球形分子部分取代梳形结构分子的传统长侧链，从而获得混合结构的高聚物分散剂BS-4。同时本项目也利用高级羧酸酐作为外壳对HPEI进行表面改性，获得核壳结构球形高聚物分散剂BS-2。本项目还综合应用了球形表面改性及梳形分子结构合成两种技术，将聚酰胺胺直接通过酯化嫁接在聚丙烯酸或聚甲基丙烯酸分子羧基上，获得外形似“冰糖葫芦串”的分子结构。混凝土及水泥净浆试验表明上述几个新型高聚物分散剂都具有优异的分散减水性能。本项目同时按照预定的研究计划开展了新型球形内核结构的研究，虽然取得了一定的研究成果，但总体判断不具备市场化应用前景，从而放弃研究工作的继续深入。对于几个可以商业化应用的几个成果，本项目开展了产业化应用研究，从生产方案的设计及设备的选型都开展了深入的系统研究，可以达到产业化条件。