【作者】 张凯；

【导师】 窦艳丽； 孙海；

【作者基本信息】 吉林大学 ， 材料工程（专业学位）， 2021， 硕士

【摘要】 过渡金属催化的乙烯与极性单体共聚合一直是高分子合成领域的热点和难点之一,极性单体的极性基团与催化剂活性中心螯合后形成的络合物,抑制了烯烃单体双键的配位与插入反应,从而使催化剂失去催化活性。另外,通过配位聚合方法将乙烯与共轭双烯共聚,将乙烯引入到聚共轭双烯主链中可赋予共聚物优异的物理和力学性能,如提高其拉伸强度、增强其抗老化性能等。但乙烯与共轭双烯这两种单体的催化剂活性种不同、聚合机理也不同,很少有催化体系能够使这两种单体有效地共聚到一起,形成序列和立构规整性可控的聚合物。本文主要设计合成了六种空间位阻和电子效应不同的芴基配体螯合的稀土配合物:（FluCH₂Ph）Sc（CH₂Si Me₃）₂（THF）（1）、（FluCH₂Py）Sc（CH₂Si Me₃）₂（2）（FluC₂H₄NHCMe）Sc（CH₂Si Me₃）₂（3）、（FluC₂H₄NHCⁱPr）Sc（CH₂Si Me₃）₂（4）、（FluC₂H₄NHCC₆H₂Me₃-2,4,6）Sc（CH₂Si Me₃）₂（5）、（2,7-^tBu₂FluC₂H₄NHCMe）Sc（CH₂Si Me₃）₂（6）。研究了这六种稀土金属配合物对乙烯与卤代苯乙烯、共轭双烯的共聚行为。主要工作如下:（1）研究了稀土金属配合物1、2、3、5对乙烯和卤代苯乙烯的共聚行为。发现催化剂3可催化乙烯与对氟苯乙烯（pFSt）、对氯苯乙烯（pClSt）或对溴苯乙烯（pBrSt）无规共聚。所得共聚物中,pFSt、pClSt、pBrSt的插入率最高可达46.3 mol%、45.1 mol%、37.5 mol%。当聚合温度由20℃升至60℃,乙烯与对氟苯乙烯的共聚活性由5.64×10⁵ g mol_Sc^-1h^-1增加到8.10×10⁵ g mol_Sc^-1h^-1。然而,对于乙烯与对氯苯乙烯,降低聚合温度反而有利于提高其共聚活性。乙烯与对溴苯乙烯的无规共聚只能在较低温度下实现。（2）考察了稀土金属配合物1～6对乙烯和丁二烯的共聚行为。甲基取代的N-卡宾-芴基限制几何构型配体螯合的钪配合物3对乙烯与丁二烯共聚表现出超高活性,是迄今报道的活性最高的催化体系。在60℃、6 bar乙烯压力下,该催化剂的催化活性高达1.64×10⁶g mol _Sc^-1h^-1。而3对乙烯和丁二烯这两种单体的均聚活性都较低,表明了其显著的正共聚单体效应。所得共聚物中,丁二烯的含量在50 mol%以下,丁二烯以trans-1,4结构为主,具有较高的乙烯与反1,4-丁二烯交替序列,分子量高达20.0×10⁴ g mol^-1。所得共聚物中还含有一定比例的顺式-1,4、1,2和环己烷结构单元,从而降低了共聚物分子链的规整度和结晶度,使得它成为一种有潜力的橡胶。将乙烯与丁二烯共聚物和炭黑进行共混硫化后,发现炭黑填充的乙烯与丁二烯硫化橡胶具有优异的拉伸强度、耐老化以及耐刺穿性能。（3）催化剂3还能得到乙烯与异戊二烯、乙烯与月桂烯的无规共聚物,并且共聚物均没有聚乙烯链段的熔融峰。更多还原

【Abstract】 Copolymerization of ethylene with polar monomers catalyzed by transition metal complexs has always been one of the challenges in the field of polymer synthesis.The complex formed by the chelating of polar group of polar monomer with the active center of the catalyst inhibits the coordination and insertion of the double bonds of olefin monomers,thereby losing the catalytic activity of the catalyst.In addition,through the coordination copolymerization of ethylene and conjugated dienes,incorporating ethylene units in polyconjugated dienes endow the copolymers excellent physical and mechanical properties,such as improving its tensile strength and enhancing its aging resistance of.However,the catalytic activity and polymerization mechanism of ethylene and conjugated dienes are different,few catalytic systems can effectively copolymerize ethylene and conjugated dienes to form polymers with controllable sequence and stereoregularity.In this thesis,we designed and synthesized six kinds of rare-earth complexes chelated with fluorenyl ligands with different steric hindrance and electronic effects:（FluCH₂Ph）Sc（CH₂Si Me₃）₂（THF）（1）,（FluCH₂Py）Sc（CH₂Si Me₃）₂（2）（FluC₂H₄NHCMe）Sc（CH₂Si Me₃）₂（3）,（FluC₂H₄NHCⁱPr）Sc（CH₂Si Me₃）₂（4）,（FluC₂H₄NHCC₆H₂Me₃-2,4,6）Sc（CH₂Si Me₃）₂（5）,（2,7-^tBu₂FluC₂H₄NHCMe）Sc（CH₂Si Me₃）₂（6）.Copolymerization of ethylene with halogenated styrenes and conjugated dienes were studied by rare-earth precurcers 1～6.The main work is as following:（1）Rare-earth metal complexes 1,2,3,and 5 were used to copolymerization of ethylene with halogenated styrenes.Catalyst 3 achieved random copolymerization of ethylene with p FSt,p Cl St or p Br St.In the copolymers,p FSt,p Cl St,p Br St with an incorporation level of up to 46.3mol%,45.1 mol%,37.5 mol%.Increasing reaction temperatures from 20℃to 60℃results in an increment of E/p FSt copolymerization activity from 5.64×10⁵ to 8.10×10⁵ g mol _Sc^-1h^-1.In contrast,for ethylene and p Cl St,a lower temperature is beneficial to improve the E/p Cl St copolymerization activity.The random copolymerization of ethylene and p Br St can only be realized at low temperature.（2）Rare-earth metal complexes 1～6 was used to copolymerization of ethylene with butadiene.Methy-substituted N-carbine-fluorene groups constrained-geometry configuration of scandium complexes 3 showed excellent activity for the copolymerization of ethylene with butadiene,which is the most active catalytic system reported so far.The copolymerization activity reached 1.64×10⁶ g mol _Sc^-1h^-1 at 60℃under 6 atm E pressure.But 3 has low homopolymerization activity on ethylene or butadiene,indication an obvious positive comonomer effect.The butadiene content in the ethylene-butadiene copolymers is not higher than 50 mol%and the butadiene unit is mainly trans-1,4 structure.The copolymer has a high alternating sequence ethylene-trans-1,4-butadiene.The molecular weight of the copolymer is up to 20.0×10⁴ g mol^-1.Copolymers contain a certain proportion of cis-1,4,1,2 and cyclohexane units,which reduce the degree of copolymer chain regularity and the crystallinity and make it a potential rubber.the ethylene-butadiene copolymers as vulcanizates filled with carbon black has excellent tensile strength,aging resistance and puncture resistance properties.（3）The random copolymers of ethylene with isoprene and myrcene was successfully synthesized by using catalyst 3,and the copolymers have no melting peak of polyethylene segment.更多还原