共查询到20条相似文献,搜索用时 109 毫秒
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用一维^H NMR、^13C NMR方法研究了对甲氧基偶氮苯衍生物的结构,并通过二维^1H-^1H同核相关谱(COSY)、^13C-^1H异核相关谱(HETCOR)及^13C-^1H异核远程相关谱进一步地确定了该类衍生物的^1H和^13C谱中各谱峰的归属,为研究侧链液晶聚合物结构提供了有价值的数据。 相似文献
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用^1H NMR和^13C NMR谱研究了新型电化学发光探针六氟磷酸二(4,4’;-二甲基-2,2‘-联吡啶).(4.4’-二羧酸-2,2‘-联吡啶)合钌的立体结构,通过^1H ^1H COSY,^13C-^1H HETCOR谱对其氢谱和碳谱中的各谱峰进行了归属,并给出了氢谱和碳谱峰的化学位移值。 相似文献
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三核过渡金属配合物[M3^ⅢO(OOCR)6L3]^+(M=Cr,Fe,Mn;R=CH3,C2H5,CH … 总被引:1,自引:1,他引:0
采用^1H NMR谱研究了通式为(M3^ⅢO(OOCR)6L3)^+(M=Cr,Fe,Mn;R=CH3,C2H5,CH2NH2;L=C5H5N,H2O)的一系列氧心三核过渡金属配合物,主要考察其^1H化学位移随金属、配体、温度、溶剂等因素变化而变化的规律。结果表明,骨架金属对化学位移的影响最大,M3O中的3个金属离子间存在反铁磁变换相互作用。对Mn配合物中顺磁中心对化学位移和线宽的影响机制的研究表 相似文献
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本工作用200兆赫脉冲傅里叶变换 NMR 波谱仪测定了一系列1,2-聚丁二烯样品在溶液中~13C核自旋-晶格弛豫时间(T_1)和核Overhauser效应(NOE)。较系统地研究了1,2-聚丁二烯的分子运动与化学结构、序列结构和大分子链节构成的关系,分析了乙烯基的内旋转运动。实验结果表明,顺1,4-链节中各碳的nT_1值比1,2-链节中相应各碳的nT_1值长1倍左右;对于相同的链节,当其两旁由1,2-链节变为顺1,4-链节时,其各类碳的nT_1值都大大增加;随着1,2-链节增加,各类碳的nT_1值都明显缩短。乙烯基叔碳的nT_1值大于端碳,经计算表明,引起乙烯基叔、端碳的nT_1值不相等的主要因素是乙烯基在垂直于主链的平面上的摆动。 相似文献
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Proton decoupled, partially relaxed, Fourier-transform 50.3 MHz carbon-13 NMR in naturalabundance was used to determine spin-lattice times (T_1) and nuclear Overhauser enhancement fac-tors (NOE) of individual carbon of a serics of 1,2-polybutadienes with different structures in solutionin CDCl_2 The structure dependence of molecular metion and the internal motion of vinyl group in1,2-polybutadiene have been studied by nT_1 and NOE values. The nT_1 values of the carbons in cis-1,4-units are the highest and those of the carbons in 1.2-units are the lowest in three types of units in1,2-polybutadiene. The nT_1 values of carbons in the same unit become greater when the adjacent1,2-units are replaced by 1,4-units, and nT_1 values of the carbons in all units decrease sharply withthe increase of content of 1,2-units in the polymers. The fact that nT_1 values of --CH=are larger than those of=CH_2 in vinyl group impliesthat there are complex internal motions of vinyl group. It is shown by calculation that the dominantfactor causing the difference in nT_1 of--CH=and=CH_2 in vinyl group is a swing of vinyl group ina plane peopndicular to the chain backbone. 相似文献
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James H. O'Donnell Andrew K. Whittaker 《Journal of polymer science. Part A, Polymer chemistry》1992,30(2):185-195
Solid-state 13C NMR spectroscopy has been used to determine the decrease in C?C bonds, formation of crosslinks and cis to trans isomerization during the γ irradiation of (a) > 99% cis, 1,4-polybutadiene, (b) 54% trans, 41% cis, 1,4-polybutadiene, and (c) 86% 1,2-polybutadiene. G(-cis C?C) and G(-trans C?C), were similar and decreased with dose from ≈ 40 for 0-1 MGy to 5 for 5-10 MGy. G(-double bonds) and G(crosslink) were comparable, indicating that crosslinking occurred through the double bonds. G(crosslink) was much higher than values derived from physical properties, confirming that NMR measures the total of inter- and intramolecular crosslinking (cyclization). The 1,2 polybutadiene was much more sensitive to crosslinking, and a value of G(-C?C) = 240 was obtained at low doses. Crosslinking evidently proceeds by a kinetic chain reaction in all three types of polybutadiene. 相似文献
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C60敏化的顺 1,4 聚丁二烯的光氧化周涛陈双基(信阳师范学院化学系河南464000)(北京大学分校化学系北京100083)李子臣周锡煌李福绵(北京大学化学系北京100871)关键词C60,顺 1,4 聚丁二烯,光氧化自从能以宏观量制备C60... 相似文献
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S. Bywater Y. Firat P. E. Black 《Journal of polymer science. Part A, Polymer chemistry》1984,22(3):669-672
The microstructure of polybutadiene produced by anionic initiation in diethyl ether and tetrahydrofuran with counterions Li+, Na+ and K+ was determined by 1H- and 13C-NMR. Ionization suppressing salts were added in tetrahydrofuran to ensure that only the ion-pair reaction was studied. Results are compared with older published data. In general, the 1,4 content of the polymer increases with increasing counterion size but varies somewhat with solvent with a given counterion. The cis component of the 1,4 structures changes with temperature and counterion. It is suggested that this change reflects the proportion of cis and trans centers that carry the reaction. 相似文献
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酮肼交联及硅烷偶联水性聚氨酯的成膜机理及其性能研究 总被引:8,自引:0,他引:8
用二乙醇胺(DEA)和双丙酮丙烯酰胺(DAAM)按Michael加成反应机理合成了一种新的聚氨酯扩链剂DDP(N-[(1,1-二甲基-2-乙酰基)乙基]-β-二羟乙氨基丙酰胺).以异佛尔酮二异氰酸酯(IPDI)、聚四氢呋喃二醇(PTMG1000)、二羟甲基丙酸(DMPA)、三羟甲基丙烷(TMP)等为主要原料,在用γ-氨基丙基三乙氧基硅烷(KH550)封端改性聚氨酯的基础上,采用自制含酮羰基二元醇N-[(1,1-二甲基-2-乙酰基)乙基]-β-二羟乙氨基丙酰胺(DDP)和1,4-丁二醇(BDO)作为扩链剂,制备了侧链含酮羰基的聚氨酯乳液.通过外加己二酸二酰肼(ADH),制得室温自交联乳液.利用衰减全反射红外光谱(ATR-FTIR)和核磁共振波谱(NMR)对扩链剂(DDP)和涂膜结构进行表征,ATR-FTIR和NMR测试证实了DDP的生成并参与反应合成了聚氨酯及乳液成膜时酮肼交联反应的发生.研究了n(—NHNH2)/n(—CO—)、n(NCO)/n(OH)、DDP含量对聚氨酯涂膜性能的影响.结果表明,在己二酸二酰肼(ADH)的用量为0时,涂膜的吸水率随DDP含量的增加而增大;n(NCO)/n(OH)1.40时,聚氨酯难以乳化并且乳液稳定性变差;在最佳配比n(—NHNH2)/n(—CO—)=1,n(NCO)/n(OH)=1.40的条件下,DDP%从0增大到7.22%时,涂膜的吸水率从39.36%降低到18.92%同时表现出很好的耐溶剂性能,交联度从51.49%上升至90.23%,拉伸强度从20.09MPa增大到28.26MPa,硬度达2H.热失重分析(TGA)表明酮肼交联结构的引入提高了涂膜的热稳定性. 相似文献