共查询到19条相似文献,搜索用时 108 毫秒
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C60/C70及其衍生物球碳钕系催化丁二烯聚合 总被引:1,自引:0,他引:1
C_(60)/C_(70)及其衍生物球碳钕系催化丁二烯聚合陈滇宝,赵春英,朴光哲,徐玲,仲崇祺,唐学明杨海滨,李明辉,邹光田(青岛化工学院高分子材料系,266042)(吉林大学超硬材料国家重点实验室)1实验部分原料丁二烯(Bd)为齐鲁五化公司聚合级产品... 相似文献
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通过最佳定量条件的选择,在FT-80A NMR谱仪上获得了五种商品牌号DGEBA环氧树脂的~(13)C谱。谱峰的精细差别反映了样品微观链结构的差异。通过平均聚合度(?),数均分子量(?)_n,环氧端基对整个端基比值EER,以及环氧当量值EEW,定量地揭示了不同样品的微观链结构。 相似文献
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采用13C NMR及FTIR对霍林河褐煤的化学结构特性进行深入分析,通过13C NMR计算得到霍林河褐煤包含34.32%的脂肪族碳、61.25%的芳香族碳以及4.43%的羰基碳。平均每个芳环团簇包含1~2个芳香环,每个芳香环中平均碳原子取代数为3~4。平均亚甲基碳链数为1.4,烷链支化度为25.47%,说明脂肪族多以短链分支形式存在。通过对霍林河褐煤红外光谱进行分峰拟合,计算得到煤的FTIR结构参数(平均亚甲基碳链数、芳香环取代度、烷链支化度)与13C NMR计算结果相吻合。虽然芳碳率(far-F=55.37%)与13C NMR计算结果存在一定的偏差,但是FTIR很大程度上仍然可以反映煤的碳骨架结构特性。 相似文献
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考察了由Nd(vers),(简称Nd)、Al(i-Bu)2H(简称Al)争Al(i-Bu)2Cl(简称Cl)组成的均相催化剂体系在5L釜中于70℃聚合丁二烯的反应规律,并在2m3装置上进行了放大试验.结果表明,该均相钕系催化剂具有高的稳定性;Al/Nd(摩尔比)是影响相对分子质量分布的重要因素,当Al/Nd低于20时,产物的相对分子质量分布在3.00以下;改变Nd/Bd(摩尔比)或使用不同组成的Al,可改变聚合产物的门尼黏度,但对相对分子质量分布无明显影响.在2m3装置上,采用均相钕系催化荆可以得到收率大于90%、相对分子质量分布小于3.00和顺式-1,4-结构摩尔分敷大于97.0%的聚丁二烯. 相似文献
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高分辨固体^13C—NMR和XPS技术表征碳的骨架结构 总被引:1,自引:0,他引:1
本文用高分辨固体^13C-NMR和XPS技术表征了抚顺老虎台气煤吡啶抽提残煤及其热解加氢产物中四氢呋喃不溶/吡啶可溶物和吡啶不溶物的碳骨架结构。固体^13C-NMR谱的研究结果表明:三个样品的芳香组体积平均碳原子数分别是为19,22,25个,芳香环数目依次是5.0,5.8,6.7个。随样品中碳元素百分含量(C%)的增加,芳香组体积的平均碳原子数目和芳环数目都增加。XPS分析结果表明:碳元素主要以类 相似文献
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研究钕系顺丁橡胶(NdBR)的微观结构与性能,并与镍系顺丁橡胶(NiBR)对比。结果表明:与NiBR相比,NdBR的顺式-1,4-结构含量和重均相对分子质量较大,门尼粘度相近,与炭黑结合能力较强,硫化胶的强伸性能和弹性较好,压缩永久变形较小,生热和滚动阻力较低,抗湿滑性能较差;与中试NdBR2003相比,中试NdBR2012的相对分子质量分布较窄,混炼胶的硫化速度较快,硫化胶的强伸性能、弹性和耐屈挠性能较好,压缩永久形较小,生热和滚动阻力略低,抗湿滑性能稍差。 相似文献
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K.D. Skuratov M.I. Lobach A.N. Shibaeva L.A. Churlyaeva T.V. Erokhina L.V. Osetrova V.A. Kormer 《Polymer》1992,33(24):5202-5207
The structure of initial, ultimate and inner chain units in polybutadiene produced with NdCl3. 3(i-PrOH)---HAl(i-Bu)2was studied by means of 13C nuclear magnetic resonance spectroscopy. Initial units are shown to be predominantly of trans-CH3CH=CHCH2--- structure. Conversely, 90% of inner units have cis configuration. Ultimate units obtained by quenching with H2O (D2O) are predominantly of 1,2 structure. On the basis of the data obtained, the polymerization mechanism was discussed. 相似文献
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A series of phenol-formaldehyde resins was produced in the presence of NaOH catalyst. Detailed structural and quantitative information was provided by 13C-NMR spectroscopy. The main interests were the relative quantities of bridge structures, methylol groups, and free phenol. Functionality and linearity of resins were also studied. The effects of the condensation F/P molar ratio on the structure and properties of the resins was studied by gel permeation chromatography (GPC) and differential scanning calorimetry (DSC) in addition to 13C-NMR. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 1183–1193, 1997 相似文献
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定量~(13)C-NMR谱表征蔗渣碱木素结构 总被引:4,自引:0,他引:4
从蔗渣纸浆黑液中制出纯蔗渣碱木素,然后测定其定量13C-NMR谱.图谱分析表明,蔗渣碱木素主要由紫丁香基,愈创木基和对羟苯基三种丙烷结构单元组成,其中未绩合的紫丁香基、愈创木基和对羟羊基含量比为2.2:1.0:1.4.蔗渣碱术素结构单元间主要以β-O-4烷基芳基醚键连接,也有一定量的非环状α-醚键存在.蔗渣碱木素中,相当部分对香豆酸类结构并非通过酯键而是通过醚键或碳双键连接于芳核上. 相似文献
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负载钛体系催化合成聚1-丁烯的结构与性能 总被引:14,自引:4,他引:14
对负载钛体系催化合成的聚1-丁烯(PBt)进行了结构表征和性能的测试。DSC测试表明,PBt有两个熔融峰,分别为43.5℃和112.4℃,玻璃化温度为-23.4℃;热-机械分析表明PBt的软化点为80℃,粘流温度为165℃;脆性温度为-21℃;PBt的物理交联点间平均相对分子质量为2400;应力-应变曲线呈典型的弹性体特征;PBt具有优良的耐酸碱性、良好的绝缘性和介电性,其介电损耗正切值介于极性和非极性材料之间;永久形变在90%-150%之间 相似文献
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This article is concerned with the microstructural changes during peroxide and high pressure vulcanization of polybutadiene that is unfilled and filled with carbon black. The main tool is 13C solid-state NMR; it shows that vinyl unsaturations are consumed in both filled and unfilled samples under peroxide and high pressure vulcanization. Chemical shift calculations of unvulcanized polybutadiene show good agreement with the observed peaks. Calculations of proposed structures, based on a possible reaction mechanism, suggest that a large number of peaks will appear, each at very low intensity. Nevertheless, some changes can be seen as a result of the crosslinking reaction, and the results provide support for the suggested reaction mechanism. Thus, the proposed addition crosslinking mechanism over vinyl unsaturations seems to be a reasonable explanation of the crosslink formation in high pressure vulcanization. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2799–2806, 1999 相似文献
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K. D. Skuratov M. I. Lobach A. N. Shibaeva L. A. Churlyaeva T. V. Erokhina L. V. Osetrova V. A. Kormer 《Polymer》1992,33(24):5197-5201
The structure of initial and ultimate chain units in polybutadiene and polyisoprene was studied by means of 2H nuclear magnetic resonance spectroscopy. Polydienes were prepared with a neodymium catalyst; quenching was performed with deuteromethanol. The enrichment of quenched ultimate units by trans-1,4 structures at the expense of cis-1,4 structures at high polymer yields was observed. When using diisobutylaluminium deuteride DAl(i-Bu)2, as chain transfer agent, it was shown that the principal site of chain transfer reaction was the Al-D bond. The initial unit of polybutadiene was predominantly of trans-1,4 structure. 相似文献
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采用淤浆聚合法,使用3种聚丙烯催化剂制备了高乙烯含量乙烯-丙烯无规共聚物,并采用核磁共振碳谱对共聚物结构和性能进行了表征。结果表明:在相同聚合条件下,使用二醇酯化合物作为内给电子体的ND催化剂同已商业化的两种Ziegler-Natta催化剂CAT1和CAT2聚合得到的乙烯-丙烯无规共聚物中的乙烯摩尔分数接近,为75%~78%;使用ND催化剂聚合得到的乙烯-丙烯无规共聚物链段中乙烯-丙烯单元序列分布更均匀;使用ND催化剂聚合得到的乙烯-丙烯无规共聚物中橡胶相相对含量高于采用CAT1和CAT2催化剂。 相似文献