间规聚苯乙烯的合成与工业化研究

本文评述了间规聚苯乙烯（ｓＰＳ）的联合机理与工业化研究,介绍了茂金属催化剂和聚合反应器。强调要实现ｓＰＳ的工业化,尚需加强以聚合反应工艺和反应器开发为目标的聚合反应工程研究。     

茂金属间规聚苯乙烯

论述了茂金属催化体系,影响聚合和聚合物性能的主要因素,聚合反应釜以及间规聚苯乙烯的性能,加工及应用。     

制备间规聚苯乙烯的新型催化剂的研究

对位卤素取代的苯酚与五甲基三氯单茂钛在三乙胺存在下进行酯化反应，制得4种五甲基茂基三(对—卤代苯氧基)钛的新型茂钛化合物[Cp^*Ti(O—C6H4—X)3,(X为F、Cl、Br、D)]。经元素分析、质谱、核磁共振谱证实了上述结构。在甲基铝氧烷和三异丁基铝活化下，4种茂钛化合物对苯乙烯间规聚合显示出极高的催化活性，制得的间规聚合物间规度(大于96％)和熔点(大于270℃)高。4种茂钛化合物的活性从大到小依次为：五甲基茂基三(对—氟苯氧基)钛、五甲基茂基三(对—氯苯氧基)钛、五甲基茂基三(对—溴苯氧基)钛、五甲基茂基三(对—碘苯氧基)钛。     

非茂金属催化剂用于苯乙烯间规聚合

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     

茂金属间规聚苯乙烯

评述了茂金属间规聚苯乙烯的最新进展,苯乙烯间规聚合的茂金属催化体系、聚合机理、聚合工艺以及间规聚苯乙烯的性能和应用。     

茂钛催化剂合成及苯乙烯间规聚合

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。     

间规聚苯乙烯的特性及应用前景

用茂金属催化剂制得间规聚苯乙烯（ｓＰＳ）是一类新型结晶聚合物，具有优良的耐热性，耐化学性和电气性能。综合考虑价格／性能因素，ｓＰＳ在工程塑料的应用市场上具有很强的竞争力，本文对ｓＰＳ的物性及应用景景作一简要介绍。     

新型苦茂钛间规聚苯乙烯催化剂的研究

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。     

新型非茂金属间规聚苯乙烯催化剂的研究

中科院化学研究所合成了新型非茂钛类配合物,研究了该类催化剂在溶液和本体条件下催化苯乙烯间规聚合,完成了苯乙烯间规聚合的模试实验,并研究了所得间规聚苯乙烯的物理性能和加工性能。     

间规聚苯乙烯的研究开发

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。     

Novel monotitanocene and methylaluminoxane catalyst for syndiospecific polymerization of styrene

Syndiotactic polystyrene (sPS) was synthesized with a novel monotitanocene complex of η⁵‐pentamethylcyclopentadienyltri‐4‐methoxyphenoxy titanium [Cp*Ti(OC₆H₄OCH₃)₃] activated by methylaluminoxane (MAO) in different polymerization media, including heptane, toluene, chlorobenzene, and neat styrene. In all cases bulk polymerization produced sPS with the highest activity and molecular weight. Solution polymerization produced much better activity in heptane than in the other solvents. Using a solvent with a higher dipole moment, such as chlorobenzene resulted in lower activity and syndiotacticity because of the stronger coordination of solvent with the Ti(III) active species, which controlled syndiospecific polymerization of styrene. With bulk polymerization at a higher polymerization temperature the Cp*Ti(OC₆H₄OCH₃)₃–MAO catalyst produced sPS with high catalytic activity and molecular weight. The external addition of triisobutylaluminum (TIBA) to the Cp*Ti(OC₆H₄OCH₃)₃–MAO system catalyzing styrene polymerization led to significant improvement of activity at a lower Al:Ti molar ratio, while the syndiotacticity and molecular weight of the yields were little affected. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1243–1248, 2001     

Syndiotactic polymerization of styrene: Study of catalyst components and polymerization conditions

Syndiotactic polystyrene (s‐PS) was prepared using monotitanocene catalyst of cyclopentadienyl titanium trichloride (CpTiCl₃) activated by methylaluminoxane (MAO). Solution polymerization was carried out in toluene using different polymerization conditions. Syndiotacticity index (SI) between 68 and 91.6% was obtained. Increasing Al/Ti molar ratio shows an increase in both conversion percentage and SI. The conversion increased linearly with increasing Al/Ti molar ratio in the range studied. The conversion reached to an optimum value of about 65% at styrene/Al molar ratio of 2.83, while no regular behavior of SI was observed with changing the ratio. Effect of temperature of the range 50–80°C on polymerization was studied. The most favorable temperature for the polymerization regarding activity is 70°C; however SI decreased with temperature up to 80°C. H₂ value to 140 mL/100 mL solvent increased the productivity of the catalyst, however further increase of H₂ reduced the activity of the catalyst. Polymerization time of 15 to 125 min shows a decrease in activity. The decrease was sharper for about 30 min of polymerization than longer time. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2216–2221, 2006     

A kinetic study of novel bimetallic titanocene catalyst for syndiospecific styrene polymerization

A kinetic study of a syndiospecific polymerization was performed with two kinds of catalysts: Cp*Ti(O(C₆H₄)CMe₂(C₆H₄)O)TiCp* [bimetallic system] and Cp*Ti(OMe)₃ [monometallic system]. The purpose of this study was to determine the reasons behind the high activity of a bimetallic catalyst system. The active site structures of the two kinds of catalysts appears to be similar to the cationic Ti [III] species having η⁵‐pentamethylcyclopentadienyl ligand, while the rate of the activation process of the bimetallic catalyst was found to be higher than that of the monometallic catalyst. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

后过渡金属烯烃聚合催化剂的研究进展

综述了以后过渡金属 (Ni,Pd ,Fe和Co)络合物为主催化剂的烯烃聚合催化剂的发现、沿革及研究进展 ,包括催化剂的合成、结构、性能、催化烯烃聚合机理等。     

Kinetics of slurry phase polymerization of styrene to syndiotactic polystyrene with pentamethyl cyclopentadienyl titanium trimethoxide and methyl aluminoxane. I. Reaction rate analysis

The kinetics of syndiospecific slurry polymerization of styrene in heptane has been investigated with pentamethyl cyclopentadienyl titanium trimethoxide [Cp??Ti(OMe)₃] catalyst with methylalmuninoxane. The experimental studies at different styrene/heptane ratios indicate that no global gelation occurs at low styrene/heptane ratios even at high styrene conversion. The effective propagation rate constant tends to decrease as polymerization rate is increased at higher initial styrene concentrations. To analyze the effect of catalyst deactivation, a novel three‐stage polymerization experiment has been designed and carried out where monomer is added during the polymerization. The experimental results show that the catalyst activity is very high at the beginning of polymerization but it decreases significantly as catalyst sites are occluded in the solid phase. We also observe that the catalyst remains active for more than 3 h and the rate decay is not solely due to intrinsic catalyst deactivation. Our experimental data suggests that physical transport effects cause the decay in the polymerization rate. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2132–2137, 2003     

合成间同立构PS用单中心催化剂的研究进展

综述了茂金属催化剂和非茂钛催化剂合成间同立构聚苯乙烯的研究进展,其中,茂金属催化剂主要包括茂钛催化剂、单茂钛催化剂、茚钛催化剂、双核金属催化剂及负载型催化剂等。今后的研究重点是负载型茂金属催化剂和非茂钛催化剂,单中心催化剂将对合成间同立构聚苯乙烯的工业化发展发挥重要的作用。     

Syndiospecific styrene polymerization with CpTiCl3/MAO: Effects of the order of reactant addition on polymerization and polymer properties

Syndiospecific styrene (St) polymerization, catalyzed by the CpTiCl₃/methylaluminoxane (MAO) system, was investigated using two different activation procedures. The polymerization parameters included polymerization time, temperature (～25–100°C), ratio of [Al]/[Ti] (～100–1000), and catalyst precursor concentration (～0.5–10.0 × 10^?4 mol Ti/L). It was found that adding reactants in the order of (CpTiCl₃ + MAO) + St (Injection of Styrene mode) gave much higher monomer conversion rates, higher weight‐average molecular weights, and narrower molecular weight distributions than for the (St + MAO) + CpTiCl₃ (Injection of Catalyst mode). The former also yielded significantly higher syndiotacticity fractions. Differential scanning calorimetry measurements showed multiple peaks exhibiting polymorphism in crystalline syndiotactic polystyrene samples. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1449–1455, 2004     

Rate and molecular weight distribution modeling of syndiospecific styrene polymerization over silica-supported metallocene catalyst

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.     

烯烃聚合后过渡金属催化剂负载化研究进展

综述了后过渡金属催化剂负载化方式和载体的种类及其催化特性,该催化剂载体包括无机载体、聚合物载体、自固载和介孔分子筛等。通过与均相催化剂性能的比较,进一步阐述了负载的目的和必要性。随着这一领域研究深入,将对后过渡金属催化剂工业化发展具有重要的意义。     

负载复合后过渡金属烯烃聚合催化剂研究进展

综述了负载和复合型后过渡金属烯烃聚合催化剂的研究进展。把后过渡金属催化剂负载化,可以适合现有工业生产的工艺要求,改善聚合物产品的形态结构、抑制粘釜现象等。用后过渡金属催化剂与其他过渡金属催化剂(如Ziegler-Natta催化剂、茂金属催化剂等)进行复合的目的主要是制备具有某些特定性能聚烯烃产物及使单一乙烯单体聚合制备支化聚乙烯。后过渡金属催化剂进行负载和复合后在改善聚烯烃产物性能、降低生产成本等方面有突出的优势．具有十分广阔的工业应用前景。