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首页> 外文期刊>Journal of Applied Polymer Science >Atom Transfer Radical Homo- and Copolymerization of Styrene and Methyl Acrylate Initiated with Trichloromethyl- Terminated Poly(vinyl acetate) Macroinitiator: A Kinetic Study
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Atom Transfer Radical Homo- and Copolymerization of Styrene and Methyl Acrylate Initiated with Trichloromethyl- Terminated Poly(vinyl acetate) Macroinitiator: A Kinetic Study

机译：三氯甲基封端的聚乙酸乙烯酯大分子引发剂引发的苯乙烯和丙烯酸甲酯的原子转移自由基均相和共聚：动力学研究

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Atom transfer radical bulk copolymerization of styrene (St) and methyl acrylate (MA) initiated with trichloromethyl-terminated poly(vinyl acetate) macroinitiator was performed in the presence of CuCl/PMDETA as a catalyst system at 90 degrees C. Linear dependence of In[M](0)/[M] versus time data along with narrow polydispersity of molecular weight distribution revealed that all the homo- and copolymerization reactions proceed according to the controlled/living characteristic. To obtain more reliable monomer reactivity ratios, the Cumulative average copolymer composition at moderate to high conversion was determined by H-1-NMR spectroscopy. Reactivity ratios of St and MA were calculated by the extended Kelen-Tudos (KT) and Mao-Huglin (MH) methods to be r(St) = 1.018 +/- 0.060, r(MA) = 0.177 +/- 0.025 and r(St) = 1.016 +/- 0.053, r(MA) = 0.179 +/- 0.023, respectively, which are in a good agreement with those reported for the conventional free-radical copolymerization of St and MA. Good agreement between the theoretical and experimental composition drifts in the comonomer mixture and copolymer as a function of the overall monomer conversion were observed, indicating that the reactivity ratios calculated by copolymer composition at the moderate to high conversion are accurate. Instantaneous copolymer composition curve and number-average sequence length of comonomers in the copolymer indicated that the copolymerization system tends to produce a random copolymer. However, MA-centered triad distribution results indicate that the spontaneous gradient copolymers can also be obtained when the mole fraction of MA in the initial comonomer mixture is high enough.
机译：在三氯甲基封端的聚乙酸乙烯酯大分子引发剂的引发下，苯乙烯（St）和丙烯酸甲酯（MA）的原子转移自由基本体共聚反应是在90℃下以CuCl / PMDETA为催化剂体系进行的。 M]（0）/ [M]随时间变化的数据以及较窄的分子量分布多分散性表明，所有均聚和共聚反应均根据受控/活性特征进行。为了获得更可靠的单体反应性比率，通过H-1-NMR光谱测定了中高转化率下的平均共聚物平均组成。通过扩展的Kelen-Tudos（KT）和Mao-Huglin（MH）方法计算出St和MA的反应比为r（St）= 1.018 +/- 0.060，r（MA）= 0.177 +/- 0.025和r （St）＝ 1.016 +/- 0.053，r（MA）＝ 0.179 +/- 0.023，这与St和MA的常规自由基共聚所报道的一致。观察到共聚单体混合物和共聚物中理论组成和实验组成的漂移随总单体转化率的变化有很好的一致性，这表明在中等转化率至高转化率下，由共聚物组成计算出的反应率是准确的。共聚物中的瞬时共聚物组成曲线和共聚单体的数均序列长度表明，共聚体系倾向于产生无规共聚物。然而，以MA为中心的三单元组分布结果表明，当MA在初始共聚单体混合物中的摩尔分数足够高时，也可以得到自发的梯度共聚物。

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