【作者】 李婷婷；

【导师】 李杨； 侯召民；

【作者基本信息】 大连理工大学 ， 高分子材料， 2013， 博士

【摘要】 探索新型稀土配合物的合成及其催化共轭烯烃聚合反应的研究是高分子合成领域的一个重要方向。共轭二烯烃(丁二烯,Bd；异戊二烯,Ip)和苯乙烯(St)是共轭烯烃聚合研究中的重要单体,它们的无规共聚产物由于分子主链上特殊多样的结构单元使其具备了优异的低温性能、高牵引性、低滚动阻力和耐磨等优点。St/Ip/Bd三元共聚物橡胶(集成橡胶,SIBR)被公认为迄今为止性能最优异的橡胶,Bd/St二元共聚物橡胶(丁苯橡胶,SBR)是合成橡胶的第一大胶种。其中,提高无规共聚物中的顺1,4-结构含量和St含量对于改善橡胶制品的弹性和耐磨性等综合性能至关重要。稀土催化剂因其在烯烃聚合中的高活性和高立构选择性等优点,逐渐成为了催化聚合领域的研究热点。本文设计合成了一系列稀土催化剂/MAO和稀土催化剂／硼试剂催化体系,分别成功制备了高顺1,4-结构、高St含量的无规稀土SBR,并且实现了无规稀土SIBR和高顺1,4-聚丁二烯(PB)、高3,4-聚异戊二烯(PI)含量的稀土丁二烯／异戊二烯二元共聚物橡胶(丁戊橡胶,IBR)的开发和制备,此外还揭示了多核茂基稀土卡宾／亚甲基配合物的聚合反应性能。具体研究内容如下：1.采用磷酸酯钕配合物(Nd(P507)3)/MAO/茚(Indene)催化体系可在较低的MAO用量下引发St/Bd进行高活性共聚合,成功制备了高St含量、高顺1,4-结构含量的无规稀土SBR。通过改变催化体系各组分配比以及聚合反应条件,可以调控聚合活性和催化剂的立体选择性。SBR的顺1,4-结构含量从34.4%增加到73.3%；结合St含量可以在较宽的范围内进行调控(-33.0%)；分子量分布较窄(Mw/Mn：1.4-2.1)。2.采用异丙氧基钕(Nd(OiPr)3)/MAO/Indene催化体系可在较低的MAO用量下引发St/Ip/Bd进行高活性共聚合,成功制备了高St含量、高顺1,4-结构含量的无规稀土SIBR。调控催化体系各组分配比和聚合反应条件,SIBR三元共聚物的顺1,4-结构从54.7%增加到82.3%；结合St含量可以在较宽的范围内(-30.4%)进行调控；分子量分布较窄(MwMn:1.5～2.2)。3.通过“NP”型非茂双齿配体2,6-iPr2C6H3N(H)PPh2(HL)与等摩尔的稀土三烷基配合物Ln(CH2C6H4NMe2-o)3(Ln=Sc, Y, Lu)反应,合成了一系列无溶剂分子配位的新型非茂稀土双烷基配合物LLn(CH2C6H4NMe2-o)2(Ln=Sc (3-1), Y(3-2), Lu(3-3)); LLn(CH2C6H4NMe2-o)2/[Ph3C][B(C6F5)4]催化体系在Bd、Ip的均聚合和共聚合中体现了高活性和高立体选择性,该体系对Bd均聚合的顺1,4-选择性为57.0%～82.4%,对Ip均聚合的3,4-选择性为93.5%～98.2%：成功制备了具有高顺1,4-PB和高3,4-PI结构特征的稀土IBR；与3-3相比,3-1和3-2对PB链段具有更高的顺1,4-选择性。4.通过考察多核茂稀土配合物的催化性能,制备了一系列结构新颖的多核茂稀土配合物,揭示了阳离子型茂稀土卡宾配合物的催化聚合性能。通过(3-5)在[PhMe2NH][B(C6F5)4]的作用下发生质子化反应成功地合成了具有立方结构的阳离子型茂稀土卡宾/亚甲基配合物[Cp’4Lu4(μ3-CH2)3(μ3-Me)][B(C6F5)4](3-13),并研究了它在烯烃聚合中的催化活性和立体选择性。研究结果表明3-13对Bd聚合具有较高的定向性,同时揭示了稀土卡宾配合物3-5对不饱和C-O、 C-N、C-S键的反应性,及其在氢化和质子化反应中的反应活性。配合物采用X-Ray单晶衍射、核磁(NMR)和元素分析进行了表征,聚合物采用NMR、红外光谱(FTIR).凝胶渗透色谱(GPC)和示差扫描量热法(DSC)进行了表征。更多还原

【Abstract】 Investigation of novel rare earth complexes and the catalytic characteristics in the polymerization of conjugated olefins is an important subject in polymer synthesis. Conjugated dienes (butadiene, Bd; isoprene, Ip) and styrene (St) are important monomers in the polymerization of conjugated olefins. Because of the multiple units in the corresponding homo/copolymers with random distribution, the polymers exhibit excellent properties such as good behavior at low temperature, high traction, low abrasion and wear. St/Ip/Bd terpolymer rubber (SIBR) is considered to be the integral rubber with comprehensive characters. Bd/St copolymer rubber (SBR) occupies the largest output in synthetic rubber. Raising the content of cis1,4-and St in random copolymers is very crucial to enhance the elasticity and wear properties. Herein, we prepared a series of novel rare earth catalyst/MAO and rare earth catalyst/borate systems, giving random rare earth SBR with high cis1,4-and St content, as well as novel random rare earth SIBR and rare earth isoprene-butadiene copolymer rubber (IBR) with unique sequences of both cis l,4-polybutadiene(PB) and3,4-polyisoprene(PI) units. Moreover, the catalytic characteristics of Cp ligated rare earth carbene/methylidene was also explored.Research contents are as follows:1. The study showed that random rare earth SBR with high content of St and cis1,4-units were prepared with neodymium phosphate compound(Nd(P507)3)/MAO/Indene system. The catalyst system showed high activity in the copolymerization even at low MAO amount. The polymerization activity and regio/stereoselectivity could be controlled by changing the molar ratio of catalyst components and polymerization conditions. The cis1,4-content increased from34.4%to73.3%; the St content could be controlled in a wide range (～33.0%); the molecular weight distributions were narrow(MwMn:1.4～2.1).2. With isopropoxide neodymium(Nd(O’Pr)3)/MAO/Indene system, random rare earth SIBR with high content of St and cis1,4-structure were prepared. The catalyst system showed high activity in the terpolymerization even at low MAO amount. When varying the molar ratio of catalytic systems and polymerization conditions, the cis1,4-content increased from54.7%to82.3%; the St content could be controlled in a wide range (-30.4%); the molecular weight distributions were narrow(Mw/Mn:1.5-2.2).3. The reaction of2,6-’Pr2C6H3N(H)PPh2(HL) with equivalent rare earth trialkyl complexes Ln(CH2C6H4NMe2-o)3(Ln=Sc, Y, Lu), afforded a series of novel non-Cp ligated and non-solvent coordinated rare earth dialkyl complexes, LLn(CH2C6H4NMe2-o)2(Ln=Sc (3-1), Y (3-2), Lu (3-3)). LLn(CH2C6H4NMe2-o)2/[Ph3C][B(C6F5)4] systems showed high activity and excellent regio/stereoselectivity in the homo/copolymerization of Bd and Ip. This catalyst system exhibited high cis,4-selectivity of57.0%-82.4%in the homopolymerization of Bd and high3,4-selectivity of93.5%-98.2%in the homopolymerization of Ip; IBR with high content of cis1,4-PB and3,4-PI sequences were prepared; comparing with complex3-3,3-1and3-2showed higher cis1,4-selectivity toward PB sequence.4. The protonation of Cp’4Lu4(μ3-CH2)4(3-5) with [PhMe2NH][B(C6F5)4] generated cubane-type cationic Cp ligated rare earth carbene/methylidene complex,[Cp’4Lu4(μ3-CH2)3(μ3-Me)][B(C6F5)4](3-13). The catalytic activity and regio/stereoselectivity in the olefin polymerization were also examined. The results showed that3-13exhibited high catalytic activity and excellent regio/stereoselectivity. The unique reactivity of3-5toward unsaturated C—0, C—N, C—S bonds were also examined, as well as the reactivity in the hydrogenolysis and protonation reactions.The complexes were characterized with X-Ray single crystal diffraction, NMR and elemental analysis. The polymers were characterized with NMR, FTIR, GPC and DSC.更多还原