NaNO_2/FeSO_4·7H_2O存在下苯乙烯活性自由基聚合的加速剂  

The Rate-accelerating Additives for Living Free radical Polymerization of Styrene in the Presence of Sodium Nitrite and Iron(Ⅱ) Sulfate

作　　者：许淼清[1] 黄剑莹[2] 颜明发[2] 林强[2] 林明华[2] 陈一虹[2] 邹友思[2] 

机构地区：[1]泉州师范学院化学系 [2]厦门大学材料科学与工程系,厦门361005

出　　处：《应用化学》2005年第9期1017-1020,共4页Chinese Journal of Applied Chemistry

摘　　要：研究了苯乙烯在AIBN/NaNO2/FeSO4.7H2O存在下的本体活性自由基聚合的加速剂。发现添加少量的丙二酸二乙酯(DEM)、乙酰丙酮(AAT)、乙酰乙酸乙酯(AAE)、丙二腈(MN),苯乙烯的聚合速率都有显著的增加。但只有MN保持了体系的活性自由基聚合的特征。实验结果表明,当n(MN)∶n(NaNO2)∶n(FeSO4.7H2O)=4∶1∶1,转化率在5 h内可达到80.0%,比未加添加剂的聚合速率(5 h 4.0%)提高了近20倍。而且得到了分子量分布较窄,分子量在4×104以下可控的聚合物,控制误差小于20%,实测分子量与理论分子量相近。1H NMR分析表明,丙二腈未连在聚合物的主链上,只是在反应中起催化加速作用。其余3种添加剂,虽然可起加速作用,但不能保持在NaNO2/FeSO4.7H2O存在下苯乙烯活性自由基聚合的特征。The rate-accelerating additives for living free radical polymerization of styrene in the presence of sodium nitrite and iron（ Ⅱ ） sulfate were studied. It was found that the styrene polymerization mediated with AIBN/NaNO2/FeSO4 · 7H2O was distinctly accelerated by the additive, such as diethylmalonate（DEM）, acetylacetone （ AAT）, ethyl acetoacetic ester （ AAE ）, or malonoitrile （ MN ）. Among those additives, malonoitrile （MN） showed the best effect of rate enhancement and maintained the character of living freeradical polymerization while accelerating the rate of the polymerization. The conversion reached 80. 0% within 5 h at 120 ℃ when n（MN） ：n（NaNO2） ：n（ FeSO4·7H2O） =4：1：1 and [MN] equaled 0. 312 mol/L . The polymerization rate was twenty times as fast as that of the polymerization without any additives. The molecular weight distribution was narrow, and the molecular weight was well controlled under 4 × 10^4, and the difference between the theoretical molecular weight and the experimental molecular weight was below 20%. With the increase of the conversion of monomer, the molecular weight of the polymer also increased linearly. The spectrum of IH NMR show that MN didn＇t alter the structure of the polymer and only acted as an accelerator.

关 键 词：活性自由基聚合 稳定自由基 丙二腈 加速剂 

分 类 号：O631[理学—高分子化学]