自交联封闭性乳液的合成与性能

以双丙酮丙烯酰胺（DAAM）、甲基丙烯酸甲酯（MMA）、丙烯酸丁酯（BA）和甲基丙烯酸（MAA）为共聚单体，采用半连续种子乳液聚合工艺合成自交联封闭性聚丙烯酸酯乳液（PAE），考察了DAAM和复合乳化剂对乳液聚合稳定性以及涂膜性能的影响。研究发现：随着DAAM含量的增加，乳液聚合稳定性下降，粒径增大，涂膜的耐介质性能和交联度提高，合适的DAAM加入量为总单体质量的3.0%，DAAM和己二酰肼(ADH)的最佳摩尔比为2∶1。采用SDBS+OP-10+OP-40为复合乳化剂体系，选用乳化剂的含量为2.35%，阴/非离子乳化剂质量比为1∶1.25；复合乳化剂在种子、核、壳比例为1.5∶1∶2，制备的乳液具有较好的聚合稳定性（乳液凝胶率低和单体转化率高），乳液耐电解质（钙离子）稳定性好，涂膜具有优异的封闭性。傅里叶红外光谱（FTIR）表明在涂膜形成过程中DAAM的酮羰基与ADH的酰肼基反应生成腙（C=N），TEM分析显示乳液的乳胶粒子呈核壳结构，TGA分析发现DAAM改性的PAE降低了涂膜的热稳定性。

Synthesis and properties of ambient self-crosslinkable polyacrylate latex with sealed function

The ambient self-crosslinkable polyacrylate latexes with sealed function were synthesized by semi-batch seeded emulsion polymerization with diacetone acrylamide (DAAM), methyl acrylate (MMA), methacrylic acid (MAA) and butyl acrylate (BA) as co-monomers.The effects of DAAM and multiple emulsifiers on the emulsion polymerization stability and film performance were investigated.The results indicated that the emulsion polymerization stability decreased and the particle size of latex increased with increasing amount of DAAM, while the crosslinked degree of cured film increased and the water- or alcohol-resistance properties of cured film were improved.The optimal DAAM dosage was 3.0% (mass) and the molar ratio of DAAM to adipic dihydrazide (ADH) was 2∶1. On the other hand, the emulsion polymerization displayed high stability (low agglomeration and high monomer conversions), polyacrylate latexes exhibited good electrolyte stability, and its cured films possessed excellent sealed function.Sodium dodecyl sulphonate(SDS), nonyl phenol ethoxylates (OP-10) and OP-40 were used as multiple emulsifiers with 2.35% (mass) of the optimal dosage, the mass ratio of SDS to OP-10 and OP-40 was 1∶1.25, and the mass ratio of multiple emulsifiers dosages in seeded, core and shell was 1.5∶1∶2.The FTIR spectrum showed that the ketone carbonyl groups of DAAM reacted with hydrazide groups of ADH to form hydrazone (C=N) during film formation.TEM picture showed that the structures of particles were core and shell, and TGA curves indicated that the thermal stability of cured film decreased, which was attributed to the presence of C=N groups.