Stereochemical assignments of the nuclear magnetic resonance spectra of isobornyl acrylate/methacrylonitrile copolymers
Stereochemical assignments of the nuclear magnetic resonance spectra of isobornyl acrylate/methacrylonitrile copolymers
复制标题
DOI：
10.1002/app.36545
复制
发表时间：
2012-11-05
影响因子：
3
通讯作者：
Shankar, Ravi
中科院分区：
文献类型：
--
作者：
Khandelwal, Deepika;Hooda, Sunita;Shankar, Ravi
以偶氮二异丁腈为引发剂，在70 ℃氮气保护下，通过自由基本体聚合，合成了不同组成的丙烯酸异辛酯（B）/甲基丙烯腈（N）共聚物。从定量13 C（1H）NMR光谱计算共聚物组成。用线性KelenTudos法和非线性误差-变量法测得B/N共聚物中共聚单体的竞聚率分别为rB = 0.66 +/- 0.11和rN = 1.54 +/- 0.22; rB = 0.74和rN = 1.65。利用极化转移无畸变增强、二维异相单量子相干和二维全相关谱对1H-NMR和13 C（1H）-NMR谱进行了完整的谱归属。N单元的腈碳和B单元的次甲基和OCH碳被分配到三单元组组成序列，而B和N单元的β-亚甲基碳被分配到四单元组组成和构型序列。N单元的α-甲基碳也被分配到构型和组成序列的三单元组水平。同样，腈和季碳共振与次甲基，亚甲基，甲基质子进行了详细研究与二维杂原子多重键相关光谱。(c)2012 Wiley Periodicals，Inc.应用聚合物科学杂志，2012年
Isobornyl acrylate (B)/methacrylonitrile (N) copolymers with different compositions were synthesized by the free-radical bulk polymerization with azobisisobutyronitrile as the initiator under a nitrogen atmosphere at 70 degrees C. The copolymer compositions were calculated from quantitative 13C(1H)NMR spectra. The reactivity ratios of the comonomers in the B/N copolymers determined from the linear KelenTudos method and nonlinear error-in-variable method were rB = 0.66 +/- 0.11 and rN = 1.54 +/- 0.22 and rB = 0.74 and rN = 1.65, respectively. The complete spectral assignments of the 1H-NMR and 13C(1H)-NMR spectra were carried out with the help of distortionless enhancement by polarization transfer, two-dimensional (2D) heteronuclear single quantum coherence, and 2D total correlation spectroscopy. The nitrile carbon of the N unit and the methine and OCH carbons of the B unit were assigned to triad compositional sequences, whereas the beta-methylene carbons of the B and N units were assigned to the tetrad compositional and configurational sequences. The a-methyl carbon of the N unit was also assigned to the triad level of configurational and compositional sequences. Similarly, the nitrile and quaternary carbon resonances with the methine, methylene, and methyl protons were studied in detail with 2D heteronuclear multiple-bond correlation spectra. (c) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012