梯度组成纳米二氧化硅／聚丙烯酸酯乳液的制备及压敏特性

The Synthesis of Silica-Sol/Acrylate Copolymer Composite Latexes with a Gradient Concentration in the Radial Direction and Their Adhesive Properties

采用半连续乳液聚合法制备了纳米二氧化硅/聚丙烯酸酯复合乳液,壳层含不同浓度梯度分布的硬单体MMA,考察了MMA含量及分布对乳液聚合过程、压敏性能的影响;动态光散射测定了乳胶粒的粒径。结果表明,壳层不同的MMA浓度分布及含量对乳液聚合过程没有影响,乳胶粒理论粒径与实测值一致,说明乳液聚合过程二次成核粒子很少,乳胶粒球形生长。动态力学分析表征了共聚物的分子运动,同时测试了初粘性、剥离力和持粘特性,并用凝胶含量、可溶部分聚合物的分子量和缠结分子量等分子参数与压敏性能相关联。

Silica-sol/acrylate copolymer composite latexes were prepared by semicontinuous emulsion polymerization. The hard monomer, methyl methacrylate （MMA）, was distributed with a gradient concentration in the radial direction, and its effects on polymerization process and adhesive properties were researched. Dynamic light scattering （DLS） was used to monitor the particle diameters and showed that the particles have grown without significant secondary nucleation occurring. The molecular parameters were characterized by gel permeation chromatography （GPC）, dynamic mechanical analysis （DMA）. Adhesive properties measured were loop tack force, peel strength and shear resistance according to FINAT test methods. The relationship between pressure-sensitive properties and molecular parameters, such as gel content and molecular weight, was evaluated.