Jung Hyejun, Song Kijong, Lee Kangseok, Lee Byung H, Choe Soonja
Department of Chemical Engineering, Inha University, 253 Yonghyundong, Namgu, Incheon 402-751, South Korea.
J Colloid Interface Sci. 2007 Apr 1;308(1):130-41. doi: 10.1016/j.jcis.2006.12.057. Epub 2006 Dec 23.
The cross-type (C-VUM) and linear-type (L-VUM) bifunctional vinyl urethane macromonomers and polystyrene (PS) using these macromonomers were synthesized in the dispersion polymerization in ethanol, and the reaction and stabilizing mechanism of the macromonomers was proposed. The structural verification of the macromonomers and PS was studied using (1)H NMR. The weight-average particle size of C-PS (PS prepared with C-VUM) and L-PS (PS prepared with L-VUM) decreased from 4.41 to 1.36 microm and from 3.56 to 1.52 microm, whereas the average-molecular weight of those increased from 34,100 to 100,500 g/mol and from 32,200 to 71,800 g/mol, respectively. The XPS result showed that the C-PS was anchored with a larger amount of PEG than that of the L-PS on the particle surface. Thus, the reaction and stabilizing mechanism of the macromonomers for the formation of PS particles is proposed as the following. The particle surface of the C-PS is surrounded by a large amount of tail shaped macromonomers leading to higher molecular weights and smaller particle sizes. On the other hand, the particle surface of the L-PS is comprised of relatively small amounts of loop shaped macromonomers inducing lower molecular weights and larger particles of L-PS than C-PS.
在乙醇中通过分散聚合合成了十字型（C-VUM）和线型（L-VUM）双功能乙烯基聚氨酯大分子单体以及使用这些大分子单体的聚苯乙烯（PS），并提出了大分子单体的反应和稳定机理。使用（1）H NMR研究了大分子单体和PS的结构验证。C-PS（用C-VUM制备的PS）和L-PS（用L-VUM制备的PS）的重均粒径分别从4.41微米降至1.36微米和从3.56微米降至1.52微米，而它们的平均分子量分别从34,100克/摩尔增加到100,500克/摩尔和从32,200克/摩尔增加到71,800克/摩尔。XPS结果表明，C-PS在颗粒表面锚固的PEG量比L-PS多。因此，提出了大分子单体形成PS颗粒的反应和稳定机理如下。C-PS的颗粒表面被大量尾状大分子单体包围，导致分子量更高且粒径更小。另一方面，L-PS的颗粒表面由相对少量的环状大分子单体组成，导致L-PS的分子量较低且颗粒比C-PS大。
