茂金属及（α-二亚胺）镍催化烯烃聚合机理及聚合物链结构调控

发布时间：2018-04-21 12:28

  本文选题：烯烃聚合机理 + 茂金属催化剂　； 参考：《浙江大学》2017年博士论文

【摘要】：热塑性弹性体(TPE)具有热塑性树脂的可塑加工特性以及传统热固性橡胶的高弹性、高强度、高回弹性性质,它打破了橡胶和塑料之间的传统界限,在节能、环保方面比传统材料更具有经济和社会效益。而其中聚烯烃类的嵌段共聚物成为越来越重要的热塑性弹性体品种。另一方面,虽然茂金属、后过渡金属等新一代金属有机催化剂在生产高性能聚烯烃(包括TPE)上已取得巨大的成功,其催化烯烃聚合过程的微观机理仍有许多重要环节未被充分了解,包括活性中心数(也即金属有机配合物活化成催化中心的比例)、微观动力学行为及其与聚合物链结构的关系等重要方面有待研究。本论文通过在金属有机催化体系中建立酰氯淬灭法,研究了活性中心数的变化,进而研究这类体系催化聚合体系的反应机理和活性中心结构。通过多种均相催化剂的烯烃共聚,制备了具有多嵌段结构的聚烯烃共聚物,并对聚合物结构—性能进行了深入研究,为聚烯烃热塑性弹性体的合成提供了新的思路及理论基础。1.将噻吩-2-甲酰氯(TPCC)淬灭法应用于金属有机催化烯烃聚合体系中,通过研究不同催化剂、淬灭时间以及淬灭剂用量,发现在淬灭时间3～20min、淬灭剂量TPCC/A1 = 2～8时,TPCC与活性链向铝转移产物之间的反应可以忽略,TPCC能高效、专一地与活性中心进行反应,使每条活性链端带有一个噻吩基团。淬灭后聚合物的硫含量等于活性中心数量。2.利用所建立的TPCC淬灭法。研究多种均相催化剂催化乙烯聚合过程中活性中心数以及动力学行为的变化,发现(α-二亚胺)镍催化剂的活性中心比例通常小于50%。桥联茂金属乙撑双茚基二氯化锆(Met.1)催化体系中活性中心比例与助催化剂种类有紧密关系。无桥茂金属催化剂双(2,4,7-三甲基茚基)二氯化锆(Met.2)在不同助催化剂活化下均能充分活化。两种无桥茂金属催化剂双(2,4,6-三甲基茚基)二氯化锆(Met.3)和双(2,4,5,6-四甲基茚基)二氯化锆(Met.4),虽然在聚合反应初期的活化率较高,但其则活性中心比例在聚合一段时间后明显衰减。3.桥联茂金属Met.1催化的乙烯均聚产物是由多种活性中心生成的,这些活性中心在催化特性上的差异可按照茂金属阳离子与其反离子构成的离子对的疏松程度不同给出合理的解释。以不同种类的铝氧烷为助催化剂对不同离子对的相对含量有显著影响,其中由助催化剂带入的游离三甲基铝还会参与紧密离子对的形成。桥联茂金属催化的丙烯均聚和乙丙共聚体系中松散离子对是主要的活性中心。Met.1在催化不同单体聚合时可达到的最高活性大小顺序为:乙丙共聚乙烯均聚丙烯均聚。4.无桥茂金属催化的乙烯均聚体系含有松散、中等解离度和紧密的离子对等多种活性中心。使用dMAO或MAO作为助催化剂均能达到很高的茂金属活化率,而使用BHT-MAO时活化率很低。无桥茂金属催化的丙烯均聚体系的活性中心以松散离子对为主。无桥茂金属催化的乙丙共聚体系也含有多种活性中心,其中有利于丙烯插入的是紧密离子对,且丙烯基本上是孤立地插入链中。5.系统研究了无桥茂金属催化剂在不同反应条件下的乙丙加压共聚,并从中找到了有效调控共聚物结构、性能的条件。在适中的聚合温度、较高的乙丙投料比下,共聚物的力学性能可以得到显著的提高。以BHT-MAO活化茂金属制备的共聚物的拉伸行为无明显的屈服现象。通过控制聚合条件(催化剂浓度25μmol/L,助催化剂BHT-MAO与催化剂摩尔比1000,聚合温度50∞C,聚合压力0.7 MPa,乙烯丙烯摩尔进气比为80 mol%:20 mol%,聚合30 min),可以制备出有一定热塑性弹性体特性的乙丙共聚物。用三种无桥茂金属催化剂在优化的聚合条件下分别进行加压乙丙共聚,发现使用dMAO和BHT-MAO作为助催化剂可以有效提高所制备的共聚物的力学性能。6.用耐热型(α-二亚胺)镍催化剂N,N'-二(2,6-二异丙基苯基)亚乙基苊二亚胺二溴化镍(Ni.2)催化乙烯/长链α-烯烃共聚,得到了熔点12～103℃、很低的熔融焓以及较高的分子量的共聚物级分。这种共聚物具有高度支化聚乙烯链段和 '经历不同步数链伸直反应的长链α-烯烃单元交替连接成的链结构,其中长链α-烯烃单元进入主链及留在侧基的亚甲基序列均可形成结晶相,为共聚物提供结晶型物理交联点,使这种共聚物也具备热塑性弹性体的特性。本文的主要创新点:1.将噻吩-2-甲酰氯淬灭法测定活性中心数系统地应用于茂金属等均相催化聚合体系,并确定了适宜的淬灭反应条件。2.结合噻吩-2-甲酰氯淬灭法、GPC分峰、链结构分析等研究方法,对茂金属催化烯烃体系中的多活性中心现象进行深入研究,初步揭示了其微观机理。3.研究了无桥茂金属催化剂催化乙烯/丙烯反应的构效关系和共聚产物的结构与性能关系,制备了具有热塑性弹性体特性的烯烃共聚物。4.研究了耐热型(α-二亚胺)镍催化剂催化的乙烯/长链α-烯烃共聚,并制备了一种含有多个结晶性主链链段和长侧基的超支化聚乙烯,有望成为新型的热塑性弹性体。
[Abstract]:The thermoplastic elastomer (TPE) has the plastic properties of thermoplastic resin and the high elasticity, high strength and high resilience of the traditional thermosetting rubber. It breaks the traditional boundary between rubber and plastics. It has more economic and social benefits than traditional materials in energy saving and environmental protection. On the other hand, the new generation of metal organic catalysts, such as metallocene and post transition metals, have achieved great success in the production of high performance polyolefin (including TPE). There are still many important links in the micromechanism of the olefin polymerization process, including the number of active centers (i. e. gold). In this paper, the changes in the number of active centers were studied in this paper by establishing acyl chloride quenching method in the metal organic catalysis system, and the reaction mechanism and activity of the catalytic polymerization system of this kind of system were investigated. The polyolefin copolymer with multi block structure was prepared by copolymerization of various homogeneous catalysts. The structure and properties of polyolefin thermoplastic elastomers were studied in depth. A new idea and theoretical basis for the synthesis of polyolefin thermoplastic elastomers (.1.) was used for the application of thiophene -2- Methoyl chloride (TPCC) quenching method to metal organic synthesis. In the catalytic olefin polymerization system, through the study of different catalysts, quenching time and the amount of quenching agent, it is found that the reaction between TPCC and the active chain to aluminum transfer products can be ignored when quenching time is 3 ~ 20min and quenching dose TPCC/A1 = 2~8, and TPCC can react with the active center to make each active chain end with one Thiophene group. The sulfur content of the polymer after quenching is equal to the number of active centers.2. using the established TPCC quenching method. The changes in the number of active centers and the dynamic behavior of various homogeneous catalysts in the process of ethylene polymerization have been studied. It is found that the active center ratio of (alpha two imide) nickel catalyst is usually less than that of 50%. bridged ethene diene. The ratio of active center in the base two zirconium chloride (Met.1) catalytic system is closely related to the type of catalyst. The non bridged metallocene catalyst (2,4,7- three methyl inyl) two zirconium chloride (Met.2) can be fully activated under the activation of different catalysts. Two kinds of non bridge metallocene catalysts (2,4,6- three methyl inyl) two zirconium chloride (Met.3) and double (2,4,5,6) - four methylinyl) two zirconium chloride (Met.4), although the activation rate at the initial stage of polymerization is high, but the proportion of the active center attenuates obviously after a period of polymerization. The ethylene homopolymer of.3. bridged metallocene Met.1 is generated by a variety of active centers, and the differences in the catalytic properties of these active centers can be based on metallocene Yang separation. Different kinds of balanes have a significant effect on the relative content of different ion pairs, and the free three methyl aluminum, which is carried by the promoter, will also participate in the formation of the compact ion pair. The highest active size of the main active center.Met.1 in the polymerization of the main active center in the polymerization system is that the ethylene homopolymer polypropylene homopolymer polypropylene homopolymer poly.4. non bridged metallocene catalyzed by the ethylene propylene homopolymer contains loose, medium dissociation and close ionic reciprocal active centers. The use of dMAO or M AO as a co catalyst can achieve high metallocene activation rate, while the activation rate of BHT-MAO is very low. The active center of the propylene homopolymer system catalyzed by non bridged metallocene is dominated by loose ions, and the ethylene propylene copolymerization system catalyzed by no bridge metallocene also contains a variety of active centers, and the propene is inserted into the compact ion pair. Propene is basically the.5. system in the isolated insertion chain to study the ethylene propylene polymerization under different reaction conditions for the non bridge metallocene catalyst, and found the conditions to effectively regulate the structure and properties of the copolymer. The mechanical properties of the copolymers can be significantly improved at moderate polymerization temperature and higher ethylene propylene feed ratio. BH The tensile behavior of the copolymers prepared by T-MAO activated metallocene has no obvious yield. By controlling the polymerization conditions, the catalyst concentration is 25 mu mol/L, the catalyst BHT-MAO and the catalyst molar ratio are 1000, the polymerization temperature is 50 infinity C, the polymerization pressure is 0.7 MPa, the molar ratio of ethylene to propylene is 80 mol%, 20 mol%, and 30 min is polymerized, and a certain heat can be prepared. Ethylene propylene copolymer characterized by plastic elastomer. Using three kinds of non bridge metallocene catalysts under optimal polymerization conditions, the copolymerization of EPDM was carried out under the optimized polymerization conditions. It was found that the use of dMAO and BHT-MAO as a co catalyst can effectively improve the mechanical properties of the prepared copolymers,.6. with the heat resistant (alpha two imide) nickel catalyst N, N'- two (2,6- two isopropyl benzene). The ethylene / two imide dibromide dibromide (Ni.2) catalyzes the copolymerization of ethylene / long chain alpha olefin, and the melting point 12~103, the low melting enthalpy and the high molecular weight copolymer grade. This copolymer has a highly branched polyethylene chain and a chain of long chain alpha olefin units that undergo an unsynchronized chain extension reaction. Structure, in which the long chain alpha olefin unit can enter the main chain and the methylene sequence left in the side group can form the crystalline phase, providing the crystalline physical crosslinking point for the copolymers, making the copolymer also possess the properties of the thermoplastic elastomer. The main innovation of this paper is: 1. the determination of the number of active centers by the thiophene -2- Methoyl chloride quenching method is applied to the metallocene system. Metal homogeneous homogeneous catalytic polymerization system, and the suitable quenching reaction conditions.2. combined with thiophene -2- Methoyl chloride quenching, GPC peak, chain structure analysis and other research methods, the multi activity center phenomenon in the olefin catalyzed by metallocene catalyzed by metallocene is deeply studied, and its micro mechanism.3. has been revealed to study the catalysis of non bridge metallocene catalyst. The relationship between the structure-activity relationship of ethylene / propylene and the structure and properties of the copolymers, the olefin copolymer.4. with the properties of the thermoplastic elastomer was prepared to study the ethylene / long chain alpha olefin copolymerization catalyzed by the heat-resistant (alpha two imide) nickel catalyst, and a hyperbranched poly (b) containing a number of crystalline main chain segments and long side groups was prepared. It is expected to be a new type of thermoplastic elastomer.

【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TQ334;O643.3
，

本文编号：1782432