【作者】 毛友钢； 宋瑞方；

【Author】 Yougang Mao Ruifang song(Key Laboratory for Molecular Spectra & Structure,Jilin University,Changchun,130023,P.R.China )

【机构】 吉林大学理化所分子光谱与分子结构开放实验室；

【摘要】 本文对聚合反应中产生的增长自由基各种类型ESR谱进行了指认。结果表明它们均为自由基两个稳定的内旋转构象R1和R2的特征谱或表现谱的叠加。R1表现为一个6线特征谱,在某些条件下变为表观4线或3线谱。R2表现为一个8线特征谱.在某些条件下变为表观6线谱。本体聚合反应初期的12线谱是R1和R2的特征谱按3:1叠加而成。本体聚合反应中期的4线谱主要来源于R1的4线表观谱,它是由R1的特征6线谱中的2、3两线和4、5两线分别增宽融合而成。本体聚合反应后期的6线谱主要来源于R2的6线表观谱,它是由R2的特征8线谱中的2,3两线和6、7两线分别增宽融合而成。聚合反应中苯乙烯增长自由基的固态3线谱是R1的表观谱,它是由R1的特征6线谱中∑Mr=0线各向同性增宽消失和中间2线的各向异性增宽融合而成。Bresler的12线谱是由两个具有不同G值的R2的6线表观谱按1:1浓度比交替叠加而成。谱形或增宽程度的大小反映了活性中心的扭曲振荡运动所受阻力的大小,并对自由基聚合反应活性产生影响。更多还原

【Abstract】 Reported here is the study on various types of ESR spectra of the propagating radical,in Polystyrene.Spectrum simulation, the analysis of the hyperfine coupling constant and calculations of the conformation energy show that.the propagating radical of Styrene has two stable inner-rotation conformations R1 and N.2.R1 corresponds to a 6-line spectrum which in some special condition,can appear as an apparent 4- line or 3-line spectrum.R2 corresponds to a 8-line spectrum which in some special condition,appear as an apparent 6-line spectrum.All the ESR spectra observed in polymerization process can be.regarded as the superposition of these typical or apparent spectra.That is,the 12-line spectra in bulk polymerization is the superposition of a typical spectrum of R1(6-line spectrum) and a typical spectrum of R2(8-line spectrum) with a concentration ratio of R1/R2=3.0.The 4-line spectrum in bulk polymerization is mainly ascribed to the R1(6-line) typical spectrum which appears as an apparent 4-line spectrum because of the broadened coalescence of line-2 with line-3 in R1l(6-lines) typical spectrum,as well as line-4 with line-5.The 6-line spectrum in bulk polymerization is mainly ascribed to the R2(8-line) typical spectrum which appears as an apparent 6-line because of the broadened coalescence of line-2 with line-3 in R2(8-line) spectrum,as well as line-6 with line-7.The 3-line ESR spectra of Styrene radical in solid state comes from the typical 6-line spectrum of R1 which appears apparent 3-line spectrum because the isotropic broadening of hf components (alternative broadening) caused by the hindered oscillation ofβ-proton leads to lines withΣM■=0 in the 6-line spectrum of R1 to disappear and anisotropic broadening of hf components caused byα-proton leads to the 2 central lines in the 6-line spectrum of R1 coalescing into a single line,The Bresler’s 12-line spectrum is the superposition of two apparent 6-line of R2 with different G factors according to a concentration ratio of 1:1.更多还原