State Key Laboratory of Material-Oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009, PR China.
Langmuir. 2010 Feb 2;26(3):1724-33. doi: 10.1021/la9037809.
We reported herein the synthesis of poly(methacrylic acid)-b-poly(butyl acrylate) (PMAA-b-PBA) block copolymers (surfmers) and their performance as novel polymerizable macrosurfactants in emulsion polymerization. The surfmers bearing terminal unsaturated carbon-carbon double bonds were first successfully designed and sythesized via catalytic chain transfer polymerization (CCTP) and radical addition-fragmentation polymerization (RAFT) techniques. The structures of surfmers were characterized by Raman spectra, nuclear magnetic resonance ((1)H NMR), and gel permeation chromatography (GPC). The critical micelle concentration of surfmers was determined. Subsequently, the surfmers were used as emulsifier to prepare polyacrylate latexes (PA-surf). The influence of the surfmer concentration as well as PMAA and PBA chain segment ratios of surfmer on their performance in emulsion polymerization was discussed thoroughly. The particle size, amount of coagulum, and stability against electrolyte solutions of the latexes were evaluated. Also, the relations between monomer conversion in emulsion polymerization, polymerization rate, emulsion particle size, surface tension, and reaction time were investigated, which showed some interesting information for the probable mechanism underlying this emulsion polymerization system. Atomic force microscopy (AFM) and attenuated total reflection Fourier transform infrared spectra (ATR FT-IR) were performed to investigate the surface morphology and component distribution of the latex films. The results show high efficiency of these surfmers in emulsion polymerization, suggesting that the resultant PMAA-b-PBA block copolymers act not only as the emulsifier but also as the stabilizer of monomer droplets as well as the so-called comonomer.
我们在此报告了聚（甲基丙烯酸）-b-聚（丙烯酸丁酯）（PMAA-b-PBA）嵌段共聚物（surfmers）的合成及其作为新型可聚合大分子表面活性剂在乳液聚合中的性能。通过催化链转移聚合（CCTP）和自由基加成-断裂聚合（RAFT）技术，首次成功设计并合成了带有末端不饱和碳-碳双键的 surfmers。通过喇曼光谱、核磁共振（1H NMR）和凝胶渗透色谱（GPC）对 surfmers 的结构进行了表征。测定了 surfmers 的临界胶束浓度。随后，将 surfmers 用作乳化剂制备聚丙烯酸酯乳液（PA-surf）。详细讨论了 surfmer 浓度以及 surfmer 中 PMAA 和 PBA 链段比例对其在乳液聚合中性能的影响。评估了乳液的粒径、凝胶含量和对电解质溶液的稳定性。还研究了乳液聚合中单体转化率、聚合速率、乳液粒径、表面张力和反应时间之间的关系，这为该乳液聚合体系的可能机理提供了一些有趣的信息。原子力显微镜（AFM）和衰减全反射傅里叶变换红外光谱（ATR FT-IR）用于研究乳胶膜的表面形态和组成分布。结果表明，这些 surfmers 在乳液聚合中具有很高的效率，表明所得的 PMAA-b-PBA 嵌段共聚物不仅作为乳化剂，而且作为单体液滴的稳定剂以及所谓的共聚单体。
