共查询到18条相似文献,搜索用时 125 毫秒
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介绍了1990-2000年期间发布的高乙烯基聚丁二烯橡胶(HVPBR)合成专利的分布情况,分析了锂系、钴系、钼系引发剂体系合成HVPBR的专利技术,并提出了我国开发HVPBR合成技术的对策。 相似文献
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采用n(正辛醇)/n(Ti)=30改性TiCl4/MgCl2合成中乙烯基聚丁二烯弹性体,考察了陈化方式厦条件时单体转化率扣聚合物相对分子质量的影响。结果表明:Bd—Al-Ti三元陈化催化荆聚合活性高于Al-Ti二元陈化;最佳陈化条件:陈化单体n(Bd)/n(Ti)=20。陈化温度60℃。陈化时间30min;60℃三元陈化所得产物的相对分子质量高于室温(20℃)三元陈化的;而二元陈化产物的相对分子质量高于三元陈化,且随陈化时间的延长,聚合物的特性粘数先上升后下降。 相似文献
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正辛醇改性负载钛催化剂合成聚丁二烯橡胶 总被引:3,自引:1,他引:2
In our previous work, medium vinyl polybutadiene rubbersynthesized by TiCl4/MgCl2modified with different kinds andlevels of alcohols had been reported[1]. In this communica-tion,mechanical properties of raw rubber and vulcanizate ofpolybutadiene rubber sy… 相似文献
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研究钼系高乙烯基聚丁二烯橡胶(HVBR)胶料与几种常用橡胶胶料阻尼性能和物理性能的差异,以及无机填料品种和用量对HVBR胶料阻尼性能的影响。结果表明:与天然橡胶(NR)、丁苯橡胶(SBR)和丁基橡胶(IIR)胶料相比,HVBR胶料的损耗因子(tanδ)峰值大,阻尼性能好,有效阻尼温域略窄但在常温范围内,拉伸强度较小但可满足使用要求,耐热老化性能较好;蛭石粉和中空玻璃微珠可以明显改善HVBR胶料的阻尼性能,改性碳纳米管和云母粉不能改善HVBR胶料的阻尼性能;蛭石粉和中空玻璃微珠用量分别为3和15份时,HVBR胶料的tanδ峰值大,阻尼性能好,有效阻尼温域较宽。 相似文献
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以负载TiCl3(OC4H9)催化剂引发异戊二烯聚合,研究n(Al):n(Ti)、n(Ti):n(IP)、聚合温度及聚合工艺对聚合活性的影响,以FT-IR表征了聚合物结构。结果表明:在n(Al):n(Ti)=80时催化剂具有最高的催化活性,随着n(Ti):n(IP)升高聚合转化率升高,低温预聚有利于催化效率增加。聚合所得产物为β晶型的反1,4-聚异戊二烯结晶聚合物。 相似文献
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Yoshiharu Doi Satoshi Ueki Shigeru Tamura Shigeru Nagahara Tominaga Keii 《Polymer》1982,23(2):258-262
The soluble V(acac)3-Al(i-C4H9)2Cl system initiated living polymerization of propene at ?78°C affording monodisperse polymers (). A kinetic study (of the living polymerization) was carried out to evaluate the rate coefficients for propagation. The equilibrium constant KM for a propene monomer coordinated to an active vanadium and the rate constant kp for a subsequent insertion of coordinated monomer into a living polymer chain were determined and compared with the values for the polymerization of propene with other soluble vanadium-based catalyst systems. The relation between KM and kp revealed that a strong interaction between vanadium and propene is unfavourable for the insertion of the coordinated propene into a living polymer chain. The mechanism of an initiation reaction involving alkylation and complexing of V(acac)3 with Al(i-C4H9)2Cl has been proposed. 相似文献
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以负载型TiCl4/MgCl2—Al(i-Bu)3为催化体系合成高反式丁二烯(Bd)-异戊二烯(Ip)共聚橡胶(TBIR),考察催化体系陈化方式和条件对聚合转化率的影响。结果表明,催化体系陈化有利于提高聚合转化率;三元陈化催化体系的聚合转化率大于二元陈化催化体系。三元陈化催化体系的优化陈化条件为:Ip/Ti摩尔比20;A1/Ti摩尔比20;加料顺序TiCl4/MgCl2,A1(i-Bu)3,Ip;温度20℃;时间5~10min。 相似文献
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研究了3种添加剂(D)α-氯代丙酸甲酯(MCP)、α-氯代乙基苯(CEB)、磷酸三丁酯(TBP)对MoCl3(OC8H17)2-Al(OPhCH3)(i-Bu)2(简称Mo-Al)催化丁二烯聚合的影响;考察了D的用量和加入方式对体系聚合活性及产物黏度的影响,并对产物微观结构进行表征。结果表明,在一定添加量下,MCP或CEB均可提高催化活性和降低聚合产物黏度;TBP可在很大程度上提高催化活性,但对产物黏度影响不大;最佳加料顺序为Al-Mo-D;加入D的时间间隔越长,对聚合活性的影响越不明显;所得产物为高乙烯基聚丁二烯,3种D对产物微观结构均无明显影响。 相似文献
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The effects of temperature and catalyst homogeneity on the molecular weight distribution (MWD) and stereochemical regulation of polypropylenes produced by system have been investigated. The MWD of polymers obtained at temperatures below 21°C were unimodal and narrow (), whereas those obtained at temperatures higher than 31°C were bimodal with one narrow distribution and the other broad one () at higher molecular weights. The existence of two different types of catalyst, one soluble with homogeneous catalytic centres and the other insoluble with heterogeneous catalytic centres was found in the polymerization at 41°C. At temperatures below 21°C only soluble catalyst was present and produced isotactic polypropylenes with [m]=0.65. The isospecific nature of soluble titanium-based catalyst is greatly contrasted to the syndiospecific nature of soluble vanadium-based catalyst. 相似文献
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陈化方式对负载钛催化合成聚1-丁烯的影响 总被引:1,自引:0,他引:1
以TiCl4(简称Ti)/Al(i-Bu)3(简称A1)为催化剂,合成了聚1-丁烯热塑性弹性体,考察了催化剂的陈化温度、陈化时间以及陈化1-丁烯(Bt)用量对转化率、聚合物重均相对分子质量的影响。结果表明.采用0℃下Ti-Al-Bt三元陈化方式制备的催化剂可以有效地提高单体的转化率,降低Al的用量。最佳陈化条件为:Bt/Ti(摩尔比)60,Al/Ti(摩尔比)20,0℃,20min。0℃陈化时,试样的重均相对分子质量比室温陈化的高;三元陈化试样的重均相对分子质量比二元陈化的高。在室温和0℃陈化时.陈化时间较短,试样的重均相对分子质量变化不大;随陈化时间的延长,试样的重均相对分子质量下降。 相似文献