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Three ethylene-vinyl alcohol copolymers were studied by means of the substituent chemical shift (SCS) method. The SCS parameters of hydroxy (-OH) in two different solvents were obtained: in deuterium oxide/phenol (20/80 W/W ) the parameters are S_1 = 42.77±0.08ppm, S_2 = 7.15±0.06 ppm, S_3 (s)= -4.08±0.02ppm, S_3 (t) =-3.09±0.20ppm,S_4 = 0.48±0.03ppm, S_5 = 0.26±0.05ppm. In o-dichloro-benzen-d_4 S_1(s)=44.79±0.61ppm, S_2=7.40±0.00ppm, S_3(s)=-4.51±0.17ppm, S_3(t)=-3.13 ±0.00 ppm, S_4 =0.63±0.04ppm, S_5=0.36±0.00ppm.Simultaneously the ~(13)CNMR spectra of EVA copolymers were assigned by using the SCS parameters obtained. 相似文献
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计算机辅助有机元素分析研究共聚物的组成 总被引:1,自引:0,他引:1
本文提出了计算机辅助有机元素分析计算高分子共聚物组成的一般公式,并以丙烯酰胺-丙烯酸钠共聚物为例予以验证。同时测试了AP-20系列共聚物及AT-430共聚物的共聚组成,其结果与~(13)C NMR测定数据一致。 相似文献
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In chain molecules of 1, 2-PBD, there are two kinds of gauche arrangements, which is the cause of making the spectrum of the secondary carbon in main chain of the polymer split. In such a complex system, the gauche arrangements of the secondary carbon and the tertiary carbon occupy an important position. Hence, the contribution of the tertiary carbon to the chemical shifts of the secondary carbon has a decisive effect on the sequence structure distribution. In comparison the contribution of vinyl groups is much less. The γ values are: γ_1=-6.37~-6.41 ppm represents the effect of the tertiary carbon and γ_2=0.0~-1.56 ppm the contribution of vinyl. The mean square errors are 0.364 and 0.166×10~(-2) ppm~2, respectively in the two cases of considering the effect of vinyl and vice versa. In this paper, we discuss the effects of model chain type, chain length and temperature on the bond probability. Meanwhile, it is pointed out that there exist a few cases, which are not in accord with the usual distrib 相似文献
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基于Flory的链分子统计理论, 用MM2分子力学程序改进了1,2-聚丁二烯构象分析,同时讨论了温度的影响. 着重考查了全同1,2-聚丁二烯特征比随能量的变化规律, 并且注意到聚苯乙烯, 聚丙烯酸甲酯等全同链的特征比按相似规律变化, 从而表现了聚烯烃全同链的共同特征. 相似文献
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The chain structure of 1,2-polybutadienes prepared with molybdenum catalyst systems has been studied by IR, ~(13)C-NMR and T_g method, and the method to regulate the chain structure investigated. It was found that some polar additives, e. g., allyl halides, are able to regulate not only the content of 1,2-units in the polymer, but also its configuration and sequence distribution. Attempt has been made to estimate the sequence length of stereo-isomers of 1,2-units by statistical theory. 相似文献
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The substituent chemical shift (SCS) has been applied to the assignment of the ~(13)C NMRspectrum of chlorinated polyethylene (CPE). CPE of different chlorine contents has been em-ployed and their sequence structure discussed. The results show that characteristic of CPEwith medium chlorine content is the dichloroethane structure in molecular chain. SCS param-etets have been obtained from the ~(13)C NMR spectra. It was found that the effects of chlorinecontent and temperature on SCS are negligible, but the substituent parameter S_1 reduced by0.39 ppm when C_2Cl_4 was added to solvent ODCB. 相似文献
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光学活性聚甲基丙烯酸三苯甲酯是单手螺旋链构象的聚合物,其链构象具有较高的热稳定性。这样一个手性螺旋链聚合物的热学行为是人们所关心的。本实验室合成了光学活性聚甲基丙烯酸三苯甲酯(PTrMA),聚甲基丙烯酸邻甲基苯基二苯甲酯(o-PDPTMA),聚甲基丙烯酸邻甲氧基苯基二苯甲酯(PMTrMA)和聚甲基丙烯酸对甲基苯基二苯甲酯(p- 相似文献