NaNO_2/FeSO_4存在下聚苯乙烯大分子引发剂的合成及嵌段共聚

Synthesis and Characterization of Macroinitiator Polystyrene and Block Copolymerization in the Presence of Sodium Nitrite and Iron(Ⅱ) Sulfate

用NaNO2/FeSO4·7H2O体系替代TEMPO在有机相中合成分子量可控的聚苯乙烯大分子引发剂,引发苯乙烯聚合及酯类单体[如甲基丙烯酸甲酯(MMA)、丙烯酸甲酯(MA)和丙烯酸乙酯(EA)等]聚合,得到两嵌段共聚物.其多分散性指数小于1.5,体现了可控聚合的特征.用大分子引发剂引发苯乙烯进行活性链增长,单体的转化率较高.嵌段共聚物的实测分子量与理论分子量相近,结构经1HNMR和GPC表征.NaNO2/FeSO4·7H2O体系在纯有机相中的应用降低了活性聚合的成本,有利于工业化应用.

In the presence of sodium nitrite and iron（ Ⅱ ） sulfate the controlled polystyrenes with different molecular weight weres synthesized. The polystyrene macroinitiator could initiate the polymerization of methyl methacrylate（MMA）, methyl acrylate（MA）, ethyl acrylate（EA）, and styrene（St）. All the polymerizations have the characters of the living polymerization that the molecular weight of the copolymer gradually increased with conversion and the polydispersity indexes are below 1. 5. In addition, block copolymer＇s experimental molecular weight is similar to theoretical molecular weight. The basic mechanism for the control of radical polymerization is thus a nitroxide-mediated process, such as TEMPO, and the price was reduced greatly, which is of benefits to the industries application. The block copolymerization formation was confirmed by ^1H NMR and GPC measurements.