核壳结构苯丙乳胶粉的制备与表征

The Preparation and Characterization of Styrene-acrylate Polymer Powders with Core-Shell Structure

采用半连续种子乳液聚合法,合成了具有核壳结构的丙烯酸酯聚合物乳液,利用喷雾干燥技术制得可再分散苯丙乳胶粉。研究了乳胶粉的再分散性、乳胶粉粉体颗粒到成膜过程的微观状态、核壳比例对乳胶粒核壳结构的影响、乳化剂用量对再分散性的影响及乳胶粉在干混砂浆中的成膜性能。结果表明,乳胶粉无团聚,再分散可以恢复到原乳液的纳米尺寸,成膜时蓝光明显;乳化剂用量为0.9%时,聚合稳定性和再分散性较好。透射电镜测试表明核壳比为8∶2、5∶5均得到了清晰的核壳结构的乳胶粒,扫描电镜测试表明乳胶粉在干混砂浆中可以起到良好的粘结作用。

Semi-continuous seeded emulsion polymerization was used to synthesize acrylate polymer emulsion with core-shell structure,then redispersible styrene-acrylate polymer powders could be prepared by spray drying me- thod. The redispersibility of emulsion powder, micro-morphology of emulsion powder to film forming, the core-shell ratio effect on latex particle with with core-shell structure, the amount of emulsifier effect on redispersibility and the film forming per{ormance of emulsion powder in dry-mixed mortar were systematically investigated. Results show that emulsion powder without agglomeration could be dispersed in water to reconstruct a stable and uniform are emulsion with the same particle size as the original emulsion. The polymerization stability and redispersibility are better with 0. 9 ~ emulsifier. Transmission electron microscopy shows that final copolymer emulsion made from core/shell in the ratio of 8 ： 2 and 5 ： 5 with ＂perfect＂ core-shell morphology was achieved. Scanning electron microscopy shows that emulsion powder played a good bonding role in dry-mixed mortar.