核壳型丁苯胶乳的制备及其对油井水泥石性能的影响

针对传统的丁苯胶乳敏感性强、增韧能力不足、综合性能差等问题，本文采用微滴乳液聚合方法，利用苯乙烯、液体聚丁二烯、新型含羧基功能单体X和2-丙烯酰胺基-2-甲基丙磺酸为主要原料，合成了一种具有抗盐、增韧效果的丁苯胶乳RSL-100L。透射电镜照片显示：RSL-100L具有明显的核壳结构，且在溶液中分散性良好。应用性能实验评价表明：RSL-100L胶乳改性水泥浆抗盐性能良好，早期强度发展快，具有优良的防气窜能力；与纯水泥石相比，RSL-100L胶乳改性水泥石在高强度下具有良好的形变能力和弹韧性。RSL-100L胶乳与水泥颗粒之间的作用机制探究表明：RSL-100L胶乳可通过静电吸引作用和与钙离子的络合作用吸附到水泥颗粒表面，从而填充水泥颗粒之间的孔隙和裂缝，进而防止气窜，提高水泥基复合材料的弹韧性。

Preparation of styrene-butadiene latex with core-shell structure and effect on oil well cement

To solve the problems faced by traditional styrene-butadiene latexes, such as serious sensitivity, insufficient toughening capacity and poor comprehensive properties, the styrene-butadiene latex (RSL-100L) was synthesized by emulsion polymerization of styrene, liquid polybutadiene and 2-acrylamido-2-methyl-propane sulfonic acid monomers with a new kind of functional monomers containing -COOH groups. The RSL-100L obtained was a tough and salt-toleration polymer. The TEM image indicated that RSL-100L had formed a stable core-shell structure in solution. The performance-evaluation experiments showed that the salt tolerance, early strength and gas channeling prevention of the cement slurry were improved by RSL-100L latex. The cement paste exhibited better deformation ability and elasticity property than the non-modified cement paste. The exploration of action mechanism between RSL-100L latex particles and cement grains found that the micro-size particles of RSL-100L latex could be adsorbed onto the surface of cement grains by electrostatic interaction and Ca²⁺ complex, thereby filling the pores and gaps between the cement grains, which prevent gas channeling and improve the elasticity of cement-based composites.