【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。更多还原

【Abstract】 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 free-（radical） 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 \ 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 4×10⁴,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 ¹H NMR show that MN didn′t alter the structure of the polymer and only acted as an accelerator.更多还原