功能化聚烯烃合成研究进展

综述了近年来在功能化聚烯烃合成领域的研究进展,包括烯烃配位共聚催化剂的研究和烯烃配位聚合与其它聚合方式联用制备功能化聚烯烃的研究进展.     

聚烯烃-极性聚合物嵌段共聚物最新研究进展

聚烯烃-极性聚合物嵌段共聚物(polyolefin-b-polar polymer block copolymer,POBP)包含非极性/非功能化聚烯烃和极性/功能化聚合物嵌段,由于其独特的结构和性能特点,引起了人们的广泛关注。POBP的传统用途是作为聚烯烃和其它材料(如极性聚合物)的增容剂,近年来在诸多新兴的研究领域也取得了一定应用,包括多孔渗透膜、功能性杂化纳米材料、固体聚合物电解质等。POBP的制备方法主要两种:(1)配位聚合向其它聚合方式的聚合机理转变,即首先由配位聚合制备出聚烯烃大分子引发剂,随后引发极性单体聚合得到POBP;(2)聚烯烃反应性功能化端基与极性聚合物反应性端基之间的偶联反应。本文综述了POBP的最新研究进展,重点评述了新颖的合成路径和POBP在制备新型功能材料方面的应用进展。     

主链链端功能化聚烯烃的设计、合成及其应用

设计与合成主链链端功能化聚烯烃已成为目前聚烯烃功能化研究的热点之一.本文首先对聚烯烃功能化研究进行了简要介绍,然后重点评述了自2000年以来用于设计合成主链链端功能化聚烯烃的4种方法:烯烃聚合中向链转移剂进行链转移的方法、烯烃配位活性聚合方法、烯烃阴离子活性聚合方法以及叶立德活性聚合方法.接着,对主链链端功能化聚烯烃的应用研究新进展进行了举例介绍,最后对其设计、合成及应用前景进行了展望.     

端基功能化聚烯烃的合成与应用

端基功能化聚烯烃（Cef-PO）在聚烯烃改性和构筑复杂结构聚合物方面有着重要应用。可通过控制烯烃配位聚合过程中的自发链转移反应,得到端基不饱和聚烯烃;或通过引入硼烷、磷烷、苯乙烯及其衍生物/氢气等链转移剂得到不同反应性基团封端的聚烯烃;再经进一步基团转化反应,得到多种不同性能的Cef-PO。另外,活性配位聚合过程中,通过对活性增长聚烯烃链选择性封端处理,或使用功能化的催化剂,也可以用来制备Cef-PO。通过配位链转移聚合,即聚烯烃链在催化剂金属中心和烷基金属链转移剂之间快速可逆链转移的聚合过程,可以直接得到具有高度反应活性的碳-金属键封端的聚烯烃,经化学转化得到Cef-PO。此外,叶立德活性聚合、共轭二烯烃的阴离子活性聚合和环烯烃的开环易位聚合也可以用来制备Cef-PO。向其他聚合方式（活性自由基聚合、活性阴离子聚合等）的转换及与点击化学的结合是Cef-PO应用的明显特点。Cef-PO的应用包括作为聚合物的改性剂以及用于合成具有复杂结构的聚合物。     

不同配体的稀土金属配合物在烯烃聚合领域的研究进展

催化剂在推动聚烯烃工业发展中有着举足轻重的作用,其中金属催化剂的设计与合成更是金属有机催化化学的关键.稀土金属具有独特的轨道结构、反应活性和配位准则,因此稀土金属配合物通过在金属中心周围引入空间位阻,在聚烯烃材料制备中表现出独特优势.其中配体是决定稀土金属配合物的结构、化学活性及稳定性等方面的关键因素.本综述介绍了茂基配体(烷基取代、芳基取代、茚和芴配体)和非茂基配体(大环四齿配体、三齿配体、双齿配体和单齿配体)的稀土金属配合物的发展及其在聚烯烃制备中的应用.这项工作旨在促进稀土金属催化剂在聚烯烃催化和金属有机催化领域的研究,为高端化、差异化聚烯烃聚合催化剂的制备提供新的设计思路和研究方法.     

含硅功能化聚烯烃:合成及应用

聚烯烃功能化改性是获得高性价比新材料的有效途径。含硅功能化聚烯烃(SFPO)是聚烯烃分子结构中含有机硅功能基团或有机硅聚合物链段的一类功能化聚烯烃的统称。由于有机硅功能基团及有机硅聚合物特殊的理化性质,SFPO通常具有丰富反应性或优异性能,成为一类有代表性的功能化聚烯烃。SFPO可以作为反应性中间体,用于制备具有复杂拓扑结构的功能化聚烯烃(如星型聚合物、梳型聚合物、接枝共聚物)或聚烯烃共价键接枝改性纳米材料;SFPO还可作为功能性添加剂(如增容剂、加工助剂,表面改性剂),用于开发聚烯烃新材料。近年来,研究人员在含硅功能化聚烯烃研究领域取得了系列进展,本文旨在对相关工作进行系统总结,以期引起同行注意并促进相关研究深入发展。     

基于叶立德同源聚合的聚烯烃功能化研究

近年来,新的合成方法的发现以及多种活性聚合组合策略的运用,已成为聚烯烃功能化领域的研究热点。本文首先对构筑聚烯烃分子链骨架的一种新合成方法--叶立德同源聚合的反应机理、单体及其研究现状进行了简要的介绍,然后详细评述了叶立德同源聚合分别与活性阴离子聚合、原子转移自由基聚合、可逆加成-断裂链转移聚合以及开环聚合相结合,设计、合成功能化聚烯烃共聚物的研究新进展。最后,对基于叶立德同源聚合设计、合成功能化聚烯烃共聚物的研究前景与实际应用进行了展望。     

高性能锂离子二次电池隔膜

随着电动汽车对锂离子电池功率要求的不断提高, 高性能锂离子电池逐渐成为了人们研究的热点。隔膜作为锂离子电池的关键部件之一, 发挥着隔离正负极材料以及为锂离子迁移提供通道的作用。此外, 隔膜的热稳定性也直接影响着锂离子电池的安全性能。聚烯烃微孔隔膜由于其出色的化学稳定性、机械强度以及价格低廉而被广泛应用于锂离子电池中。然而, 其热稳定性差以及不易湿润等缺点给高性能锂离子电池的广泛应用带来很大隐患。因此, 本文探讨了聚烯烃微孔隔膜的表面改性, 以此为出发点, 介绍了基于聚合物表面改性的聚烯烃微孔隔膜、基于无机纳米颗粒的聚烯烃微孔隔膜、基于有机-无机复合材料的聚烯烃微孔隔膜的研究进展。在基于无机纳米颗粒的聚烯烃微孔隔膜的介绍中, 本文还对原子层沉积法、化学气相沉积法、物理气相沉积法等先进表面改性方法进行了简单介绍。随后, 从湿法制备、相转化法、呼吸图法、静电纺丝法以及原位聚合法5种方法出发, 对其他聚合物微孔隔膜的研究进展进行了介绍。最后, 本文对将来高性能隔膜材料的研究方向上作出展望, 旨在为高性能锂离子二次电池隔膜材料的研究和应用提供参考。     

结构明确聚烯烃接枝共聚物:合成、结构与性能

实现聚烯烃功能化是制备高性能聚烯烃材料、拓展聚烯烃应用的重要手段,几十年来得到了学术界及工业界的广泛关注。聚烯烃接枝共聚物作为一类重要的功能化聚烯烃,包含聚烯烃链段（PE、PP等）及功能化聚合物链段（PS、PMMA、PEG等）,因而在提高功能单元含量的同时能保持聚烯烃单元优异的结晶、加工性能。结构明确的聚烯烃接枝共聚物,具有结构参数可控、综合性能可调的特点,对于认识聚合物材料结构-性能关系、拓展聚烯烃应用范围具有重要的学术和实际意义。聚烯烃接枝共聚物的合成方法可以分为三种类型：“共聚接枝（graft-through）”、“引出接枝（graft-from）”、“偶联接枝（graft-onto）”。前两种合成方法往往涉及烯烃配位聚合与其他聚合方式的机理转化过程;其中,反应性聚合物中间体作为大分子引发剂、大分子RAFT试剂、大分子单体参与接枝反应,实现接枝共聚物的可控制备。第三种方法思路简单明确,即利用聚烯烃侧基反应性基团与其他聚合物反应性端基之间的高效偶联反应实现接枝共聚物制备。本文从合成、结构及性能三方面较为全面地综述了结构明确聚烯烃接枝共聚物的研究进展,着重讨论了新兴合成方法及相应接枝共聚物的潜在应用。     

具有特定拓扑结构的聚烯烃高分子的合成

具有特定拓扑结构的聚合物合成一直是高分子合成化学领域的一个重要研究内容，设计和合成具有特定拓扑结构的聚烯烃高分子更是进一步发掘聚烯烃这一量大面广的通用高分子材料的性能、开拓其新的应用领域的重要手段。在催化剂和聚合方法的研究取得重要进展的基础上，近年来国际上在合成不同拓扑结构（包括嵌段、接枝、梳型和星型）的聚烯烃高分子研...     

A review on the development of liquid chromatography systems for polyolefins

Polyolefins are the most widely produced synthetic polymer commodity and are found in countless applications ranging from bottles, packaging films to bullet-proof jackets, etc. Such widely different applications rely on high variability in the physical properties of polyolefins, which is a result of variations in microstructure, chemical composition and molar mass. Though polyolefins contain only carbon (C) and hydrogen (H) atoms, the microstructures of polyolefins are extremely variable, differing in the nature of the monomers (e.g. ethylene versus propylene), the degree of branching, chemical composition in the case of copolymers and finally their molar masses. Production, research and development of polyolefins require the analysis of polyolefin samples in terms of all these parameters. Development of efficient and robust analytical techniques based on the interactive LC is reviewed. The needed computational/theoretical studies to understand the retention mechanism in the newly developed chromatography systems are discussed.     

Preparation of novel,liquid, solvent‐free,polyolefin‐based adhesives

An innovative procedure for functionalization of polyolefins was developed. It was found that synthesized polyolefins end‐capped with trimethoxysilane (silylated polyolefins) are new polyolefin‐based adhesives. To prepare the mentioned materials,1‐octene as a higher α‐olefin was cooligomerized with two linear, nonconjugated dienes (ie, 1,5‐hexadiene and 1,7‐octadiene) by using metallocene catalyst system, Cp₂HfCl₂/MAO, at room temperature. Then, amine‐terminated trimethoxysilane (3‐aminopropyltrimethoxysilane) was reacted with unsaturated bonds of synthesized cooligomers in the presence of palladium(II) acetate. Embedding of the dienes on 1‐octene oligomeric chains was explored by Fourier transform infrared (FTIR), ¹H, and ¹³C‐NMR spectroscopy. On the basis of the results, 1,5‐hexadiene showed both 1‐butene branch and five‐member ring. On the other hand, 1,7‐octadiene was incorporated by 1,2‐addition, forming both 1‐hexene branch and seven‐member ring in the cooligomer backbone. Mole percentage of C?C and cyclic moieties reached to a value of 28.54, 18.59% mol in 1‐octene/1,5‐hexadiene, and 38.04, 6.71% mol in 1‐octene/1,7‐octadiene cooligomers, respectively. Reaction of synthesized cooligomers with 3‐aminopropyltrimethoxysilane was confirmed by FTIR spectroscopy, which yielded targeted adhesives. To study the adhesion properties, resulting adhesives were applied to different substrates. Obtained results demonstrated that tensile shear strength of synthesized adhesives to polar substrates was 2.21% to 2.84% more than nonpolar substrates. Among studied systems, the best performance was achieved by1‐octene/1,7‐octadiene–based adhesive and Al substrate with tensile shear strength of 1.45 N/mm².     

双烯烃橡胶复分解-加氢制备端羧基聚烯烃

采用烯烃复分解法,以双烯烃橡胶为原料,在Grubbs II代催化剂和链转移剂(马来酸)的作用下制得相应的端羧基聚二烯烃,通过对甲苯磺酰肼/三正丙胺试剂对其进一步加氢得到端羧基聚烯烃.主要研究了反应时间、反应温度、橡胶中双键/催化剂摩尔比、橡胶中双键/链转移剂摩尔比等因素对产物分子量及分子量分布的影响.通过核磁共振氢谱(1H-NMR)和碳谱(13C-NMR)、红外光谱(FTIR)、凝胶渗透色谱仪(GPC)、热重分析(TGA)和示差扫描量热分析(DSC)对产物的结构和性能进行了测试表征.结果表明,通过调整橡胶中双键/催化剂的摩尔比或橡胶中双键/链转移剂的摩尔比可以调控产物的分子量.另外,采用该方法制得的端羧基聚丁二烯具有较高的反式1,4-结构含量,与原料相比其顺式1,4-结构含量大幅下降,从而对产物的性能产生一定影响;而以异戊橡胶为原料时并没有观察到该现象.端羧基聚二烯烃经加氢反应后转变成端羧基聚烯烃,具有更好的热稳定性.该方法合成步骤简单,产物分子量可控,为功能材料的制备提供了新的可能.     

Unsaturation Characterization of Polyolefins by NMR and Thermal Gradient NMR (TGNMR) with a High Temperature Cryoprobe

Summary: It is important to identify the types of unsaturation and to quantify the amount of unsaturation in polyolefins for understanding chain termination mechanisms of polymerization with different catalysts. Unsaturation is also closely related to processibility, weatherability of polyolefin products and the level of antioxidants to be added for stabilizing purposes. However, it can be very challenging to accurately measure samples with a low level of the unsaturation within a reasonable amount of NMR acquisition time, along with some challenging technical issues, such as dynamic range with ¹H NMR. This paper reports a new method to accurately quantify unsaturation by using multi peak presaturation ¹H NMR with a high temperature NMR cryoprobe. The limit of quantification can be less than 1 unsaturation/1,000,000 carbons with about 30 min NMR acquisition. This paper also introduces a new technique, temperature gradient NMR (TGNMR) with or without substrates, to characterize unsaturation distribution directly in NMR tube upon temperature change.     

Polyolefin,olefin copolymers and polyolefin polyblend nanocomposites

This paper reviews recent studies done in academia or industrial laboratories on polymer nanocomposites based on various type of polyolefins like homopolymers, copolymers and polyblends reinforced with various mineral (montmorillonite, bentonite, closite, laponite, layered double hydroxide, etc.) carbon based (graphite, carbon nanotubes, carbon nanofibers, exfoliated graphite, graphene, carbon black, etc.) nanofillers. The review covers their preparation, their mechanical, thermal, flammability, gas barrier capability, electrical, dielectrical, antibacterial characteristics and their potential applications like low weight structural materials, part of optical devices, thermal interface materials, electric and electromagnetic components, absorption, antibacterial materials, etc.     

High Temperature Interaction Chromatography of Olefin Copolymers

Summary: The synthesis and characterization of polyolefins continues to be one of the most important areas for academic and industrial polymer research. One consequence of the development of new “tailor-made” polyolefins is the need for new and improved analytical techniques for the analysis of polyolefins with respect to molar mass and chemical composition distribution. The present article briefly reviews different new and relevant chromatographic techniques for polyolefin analysis. For the fast analysis of the chemical composition distribution of polyolefins a new high-temperature gradient high-performance liquid chromatography (HPLC) system has been introduced. The efficiency of this system for the separation of various olefin copolymers is demonstrated. The correlation between elution volume and chemical composition can be accessed by on-line coupling of high temperature HPLC with FTIR spectroscopy. For the elucidation of the chemical composition as a function of molar mass high-temperature size exclusion chromatography and ¹H-NMR spectroscopy can be coupled. It is shown that the on-line NMR analysis of chromatographic fractions yields information on microstructure and chemical composition in addition to molar mass distribution.     

二醚型 Ziegler-Natta 催化剂催化丙烯与极性单体共聚

 以三乙基铝 (TEA) 为保护剂, 研究了 TiCl4/MgCl2/芴二醚/Al(C2H5)3 体系催化丙烯与十一烯醇或十一烯酸的共聚反应. 结果表明, 在极性单体存在下, 聚合反应活性随极性单体加入量的增加而降低, 但可保持丙烯均聚活性的一半以上, 反应活性衰减较小. 同时, 随着极性单体加入量的增加, 极性单体在共聚物中的含量增加. 与十一烯酸相比, 十一烯醇共聚具有更高的共聚活性和共单体含量. 随着共聚物中极性单体含量的增加, 聚合物的熔点和结晶温度都有所降低. 反应温度对丙烯和十一烯醇共聚的反应活性和共单体含量影响较小.     

Functionalization of polymers: Epoxidation of polyolefins

In order to produce a polymer with an epoxy group, the epoxidation of the polyolefins poly(ethylene-co-1,9-decadiene) (PED) and polybutadiene (PB) was investigated. For these reactions, in situ generated peroxy acid was most effective and convenient. Among them an H₂O₂–formic acid system gave the best result. The reactivity of PB showed the dependency on the microstructure. The reactivity of the double bond is trans>cis> vinyl(pendant) and the selectivity for the epoxidation is cis∼vinyl(pendant)≫trans.     

Dynamic rheological characterization of polyamide/modified polyolefin laminates

 In this work dynamic rheological and peel strength measurements on laminates of polyamide and several modified polyolefins were made to evaluate the interfacial compatibilization phenomena. The polyolefins used were a low-density polyethylene, without any treatment and γ-ray irradiated in air, and two copolymers, an ethylene–tert-butyl acrylate–acrylic acid terpolymer and a partially neutralized ethylene–methacrylic acid copolymer containing sodium cations. Multilayer structures containing different amounts of both interfacial surface and volume fraction were studied. Relationships between viscoelastic functions and composition were used to analyze the effect of bulk and surface modification in the polyolefins at the interface with the polyamide. The results show that dynamic rheological measurements of stratified polymers can be used as a tool to investigate interfacial activity in multiphase systems. Received: 2 January 1998/Accepted: 21 March 1998