Abstract

The effect of conjugated dinitrones N,N-dimethylglyoxaldinitrone, N,N-di-tert-butylglyoxaldinitrone, and N,N-diphenylglyoxaldinitrone on the radical polymerization of styrene initiated by azobis(isobutyronitrile) is studied. It is found that, during the polymerization of styrene at temperatures below 90°C, chains terminate on the studied nitrones to generate high molecular weight nitroxide radicals. The regularities of polystyrene synthesis in the presence of conjugated nitrones at 130°C (the first reaction order with respect to the monomer over the entire conversion range, a linear increase in molecular weight with conversion, and postpolymerization) indicate that the polymerization of styrene can be implemented under reversible inhibition conditions in the high temperature regime. It is shown that the acceptance and specific features of styrene polymerization mediated by nitroxide radicals formed in situ are directly related to the initial structure of dinitrones. For example, the presence of conjugation between phenyl and nitronyl groups in diphenyl dinitrone leads to a decrease in its accepting ability, lowering the effectiveness of high molecular weight nitroxides as polymerization regulators in the high temperature mode. Using the methods of static and dynamic light scattering, the hydrodynamic sizes of macromolecules are estimated and the form factor R_g/R_h of a linear polymer and polymers synthesized with the participation of dinitrones is calculated.

中文翻译：

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不同结构的二硝基苯介导的苯乙烯自由基聚合

摘要

缀合dinitrones的效果Ñ，Ñ -dimethylglyoxaldinitrone，Ñ，N-二-叔-butylglyoxaldinitrone，和Ñ，Ñ研究了-二苯基乙二醛醛缩丁酮对偶氮二异丁腈引发的苯乙烯自由基聚合反应的影响。发现在低于90℃的温度下苯乙烯聚合期间，链在所研究的硝酮上终止以产生高分子量的氮氧化物自由基。在共轭硝酮存在下于130°C的聚苯乙烯合成规律（相对于单体在整个转化率范围内的第一反应顺序，分子量随转化率线性增加和后聚合）表明，苯乙烯的聚合反应可以在高温条件下可逆的抑制条件下实施。结果表明，由原位形成的氮氧化物自由基介导的苯乙烯聚合反应的可接受性和特定特征与二硝基的初始结构直接相关。例如，二苯基二硝基中苯基和硝酰基之间共轭的存在导致其接受能力的降低，降低了高分子量氮氧化物在高温模式下作为聚合调节剂的有效性。使用静态和动态光散射方法，估算大分子的流体动力学尺寸并确定其形状因子 降低了高温模式下高分子量氮氧化物作为聚合调节剂的有效性。使用静态和动态光散射方法，估算大分子的流体动力学尺寸并确定其形状因子 降低了高温模式下高分子量氮氧化物作为聚合调节剂的有效性。使用静态和动态光散射方法，估算大分子的流体动力学尺寸并确定其形状因子计算出线性聚合物的R _g / R _h和在二硝基酮参与下合成的聚合物。