共查询到19条相似文献,搜索用时 46 毫秒
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间规聚苯乙烯具有低比重、优良的电气特性、耐水解性、易成型以及良好的耐热性、耐化学药品性、尺寸稳定性,在未来的许多领域具有应用价值。上海石油化工院和中山大学已经完成了新型茂钛间规聚苯乙烯催化剂的研究,创制出具有自己专利技术的产品,产品性能已达到国外同类催化剂的先进水平,同时还对聚合物的加工做了更深入的研究。 相似文献
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以均相单茂钛化合物[Cp*Ti(OPh)3 和Cp*Ti(OPhOMe)3]为主催化剂,配以烷基铝氧烷(MAO)和三异丁基铝(TIBA),进行了苯乙烯的本体间规聚合.研究发现,聚合过程中生成聚合物的快速结晶对于避免反应体系的凝胶化,制得颗粒状产物十分重要.但正因为这种结晶成核机理,使所得颗粒的形貌极不规整,调控也十分困难.聚合过程中sPS种子的加入没有明显改善生成聚合物的颗粒形态.但当聚合体系中引入少量其他聚合物后,得到了较为规整的sPS颗粒,尤其当加入的聚合物与无定形sPS热力学不相容时(如mEPDM),得到了十分规则的球状颗粒. 相似文献
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茂钛催化剂合成及苯乙烯间规聚合 总被引:2,自引:0,他引:2
介绍了茂钛催化剂CpTi(OPh)3(Cp为环戊二烯基)的合成。使用CpTi(OPh)3/MAO均相催化体系,研究了工艺条件对苯乙烯间规聚合的影响。初步探讨了以带有反应性功能基团的聚苯乙烯为载体,负载CpTiCl3后进行的苯乙烯间规聚合。同时采用了不同配体的CpTi(OR)3催化剂用于苯乙与乙烯或丙烯共聚合,得到的共聚产物是一类应用前景良好的工程塑料。 相似文献
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非茂金属催化剂用于苯乙烯间规聚合 总被引:2,自引:0,他引:2
研究开发了非茂金属催化剂用于苯乙烯的间规聚合,合成了β-二酮钛配合物/MAO,引入烷氧基的β-二铜钛配合物/MAO,8-羟基喹啉钛配合物/MAO和β-联萘酚钛配合物/MAO等催化体系,其中最好的催化体系用于苯乙烯本体聚合时,在80℃和Al/Ti比为500的聚合条件下,活性达到6×10^5g(PS)/mol(Ti).h,聚合物间规度〉95%,熔点达270℃,本文也能催化剂结构和性能关系的研究结果进行 相似文献
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均相茂金属催化剂催化苯乙烯间规聚合中搅拌的作用 总被引:2,自引:0,他引:2
在不同搅拌型式的聚合反应器中使用均相茂金属催化剂(Cp^*Ti(OR)3/MAO/TIBA催化苯乙烯本体间规聚合。研究搅拌桨型式、反应器以及搅拌速度对聚合物形态以及聚合过程的影响,并分析了搅拌、结晶和聚合之间的关系。研究表明,良好的搅拌剪切对避免凝胶、促进粉状间规聚苯乙烯的生成至关重要。聚合动力学的研究表明,搅拌转速不仅能影响聚合物的颗粒形状,也能通过改变聚合物原生晶的结晶速率从而影响聚合速率。 相似文献
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Rate and molecular weight distribution modeling of syndiospecific styrene polymerization over silica-supported metallocene catalyst 总被引:2,自引:0,他引:2
The kinetics of syndiospecific polymerization of styrene over silica-supported Cp∗Ti(OCH3)3/MAO catalyst has been investigated through experimentation and theoretical modeling. At low monomer concentrations, the polymerization rate increases almost linearly with monomer conversion, but the reaction rate becomes independent of monomer concentration at high bulk phase monomer concentrations. A kinetic model that incorporates the monomer partition effect between the solid and the liquid phases has been proposed. The model simulations show that the observed non-linear kinetics can be adequately modeled by the monomer partition model. The polymer molecular weight has also been found to increase with the monomer concentration and the polymer molecular weight distribution (MWD) is quite broad, suggesting that the catalytic behavior deviates from the single site catalytic polymerization model. The MWD broadening is modeled by a two-site kinetic model and a good agreement between the model and the experimental data has been obtained. 相似文献
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间规选择性聚丙烯茂金属催化剂的负载化 总被引:3,自引:0,他引:3
选常用载体-硅胶进行间规选择性茂金属聚烯烃催化剂的负载化研究,考察反应温度,反应时间及反应浓度对催化剂负载量的影响,并进行聚合评价,确定最佳工艺条件。正交实验结果表明,茂金属聚烯烃催化剂经负载后,其稳定性提高,适合于现有聚合工艺。 相似文献
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介绍了一种新型有机金属配合物-单茂钛,它与MAO构成的催化体系实现了间规聚苯乙烯的本体聚合,同时得到了苯乙烯间规小试聚合的优化工艺条件,铝钛比500;聚合温度40℃,聚合时间30min。 相似文献
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A commercial, linear, low-density polyethylene (LLDPE) synthesized by a metallocene catalyst was analyzed by temperature-rising elution fractionation, Fourier transform infrared, and 13C-nuclear magnetic resonance spectroscopy. It was found that the LLDPE sample is mainly butyl branch. The degree of branching decreased with increasing elution temperature. The results from wide-angle x-ray diffraction and size exclusion chromatography confirmed that the fractionation was based on the ability of fractions to crystallize rather than molecular weight. The LLDPE sample has a narrow molecular-weight distribution. 相似文献
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Blends of syndiotactic polystyrene (s-PS), thermotropic liquid crystalline polymer (Vectra A-950), and silicone rubber with two different loading levels, have been prepared through melt processing in internal mixer at 285°C. Silicone rubber was used as a compatibilizer for this blend system. The effect of silicon rubber on crystalline, dynamic mechanical, rhelogical, thermal properties, and phase morphology of the (s-PS/TLCP) blend has been investigated in details. With the addition of compatibilizer the viscosity of the blend system increased to an order of magnitude. Dynamic mechanical analysis (DMTA) and differential scanning calorimetry (DSC) results showed that the glass transition temperature (Tg) of the blend, in presence of silicone rubber, shifted towards lower temperature region. From FTIR analysis it is evident that the ‘C=O’ stretching frequency has shifted towards lower side. SEM analysis suggested that, the TLCP domain size is reduced in ternary blend in comparison to binary blend system. 相似文献