Ma Jing, Chen Hou, Liu Delong, Ji Naiyi, Zong Guangxi
School of Chemistry and Materials Science, Ludong University, Yantai 264025, China.
School of Chemistry and Materials Science, Ludong University, Yantai 264025, China.
Mater Sci Eng C Mater Biol Appl. 2013 Jan 1;33(1):570-4. doi: 10.1016/j.msec.2012.08.051. Epub 2012 Sep 6.
The technique of activators generated by electron transfer for atom transfer radical polymerization (AGET-ATRP) of acrylonitrile (AN) has been first attempted in emulsion using the procedure of "one-pot", "two-step" with polyethylene glycol monooleyl ether (Brij 35) as surfactant, cupric chloride (CuCl2) as catalyst, hexamethylenetetramine (HMTA) as ligand, carbon tetrachloride (CCl4) as initiator and ascorbic acid (VC) as reducing agent. The polymerization proceeds in controlled/living manner as indicated by first-order kinetics of the polymerization rate with respect to the monomer concentration, linear increase of the molecular weight of polyacrylonitrile (PAN) with monomer conversion and narrow polydispersity. Monomer conversion increases initially with the increase of ligand HMTA and then decreases. The ratio of [AN1] to [AN2] at 1:3 not only gives better control on the molecular weight and the molecular weight distribution, but also provides a more rapid polymerization rate. The rate of polymerization shows a trend of increase along with CCl4 content. The apparent activation energy of the polymerization is calculated to be 46.6 kJ/mol. Chain extension of PAN with AN was also carried out and the chain extended PAN with 20520 molecular weight and 1.36 polydispersity was successfully obtained.
首次尝试采用“一锅法”“两步法”，以聚乙二醇单油酸醚（Brij 35）为表面活性剂、氯化铜（CuCl₂）为催化剂、六亚甲基四胺（HMTA）为配体、四氯化碳（CCl₄）为引发剂、抗坏血酸（VC）为还原剂，在乳液中进行电子转移生成催化剂的原子转移自由基聚合（AGET-ATRP）技术合成丙烯腈（AN）。聚合反应以可控/活性方式进行，这体现在聚合速率对单体浓度呈一级动力学、聚丙烯腈（PAN）分子量随单体转化率呈线性增加以及多分散性较窄。单体转化率最初随配体HMTA的增加而增加，随后降低。[AN1]与[AN2]的比例为1:3时，不仅能更好地控制分子量和分子量分布，还能提供更快的聚合速率。聚合速率呈现出随CCl₄含量增加的趋势。计算得出聚合反应的表观活化能为46.6 kJ/mol。还进行了PAN与AN的链增长反应，成功获得了分子量为20520、多分散性为1.36的链增长PAN。
