烯烃易位聚合研究新进展环烯烃开环易位聚合和非环二烯易位聚合

本文综述了近年来环烯烃开环易位聚合和非环二烯易位聚合研究新进展，并以活性开环易位聚合催化剂作了详细概述。     

烯烃易位聚合制备遥爪聚合物及嵌段共聚物

遥爪聚合物因其聚合物链的两端带有反应性官能团,可用于制备嵌段、接枝、星形、超支化等具有特殊结构的聚合物,其制备方法主要包括传统自由基聚合与可控/“活性”自由基聚合、阴离子聚合、阳离子聚合、易位聚合和缩合聚合等。相比于其他的传统聚合方法,烯烃易位聚合是一种较为温和的、产物分子量及结构可控的聚合方法。本文主要概述在各种链转移剂的存在下,采用环烯烃的开环易位聚合(ring-opening metathesis polymerization, ROMP)和非环二烯易位(acyclic diene metathesis, ADMET)聚合制备带有各种官能团的遥爪聚合物以及与其他活性聚合方法(NMRP、ATRP、RAFT、ROP等)相结合制备嵌段共聚物的研究进展。     

活性开环歧化聚合合成梳形聚合物

综述了近年来利用活性开环歧化聚合反应合成规整结构梳形聚合物的研究工作进展。     

氨基酸功能化环辛烯单体的区域及立体选择性开环易位聚合

合成具有可控初级结构的侧链型氨基酸聚合物,使其与具有完全精确初级结构的生物大分子相媲美,在高分子合成化学中仍然是一个长期的挑战。 在本文中,设计与合成了(环辛基-2-烯-1-羰基)-L-亮氨酸酰胺甲酯(1)和(环辛基-2-烯-1-羰基)-L-亮氨酸酰胺(2),通过Grubbs二代催化的开环易位聚合,合成了具有高反式双键选择性、高头尾区域选择性的亮氨酸衍生均聚物以及共聚物,这些聚合物具有相对较窄的相对分子质量分布(1.3~1.6)。 当组成为n(1)：n(2)=50：50嵌段共聚物在丙酮中形成以亲水嵌段poly(2)为核,疏水嵌段poly(1)为壳的半径为30 nm的反相胶束。 然而,相同组成的无规共聚物则难溶于丙酮中。这些具有明确的区域及立体结构的氨基酸衍生聚合物为仿生材料的相关应用奠定了基础。     

开环易位聚合(ROMP)在星型聚合物合成中的应用进展

开环易位聚合(ROMP)是一种单环或多环烯烃进行开环聚合反应形成功能化聚合物的方法, 已经发展成为一种合成先进聚合物材料的高效方法之一. 而星型聚合物由于特殊的结构和性能将在学术和工业的材料科学和纳米技术领域中发挥越来越重要的作用. 本综述从聚合方法、聚合单体、引发剂、交联剂等方面讨论了ROMP在星型聚合物合成中的应用, 并介绍了ROMP合成的星型聚合物的应用领域和前景, 客观地评价了各种ROMP方法的优势和局限性. 这项工作旨在促进ROMP在合成星型聚合物的研究, 为合成功能性复杂星型聚合物提供新的科学研究途径, 为加快星型聚合物材料商业化的脚步添砖加瓦.     

烯烃易位聚合研究新进展 在合成嵌段共聚物及功能高分子上的应用

本文详述了利用环烯烃开环易位聚合合成，ＡＢ，ＡＢＡ和星形嵌段共聚物，接枝共聚物，氧化还原性聚合物，侧链液晶高分子，导电高分子及含金属纳米聚合物材料，并对其具体合成线路作了概述。     

结构规整的高密度两亲性接枝聚合物刷的合成及其自组装研究

大分子单体通过两种可控聚合方法, 即开环易位聚合(ROMP)和原子转移自由基聚合(ATRP)的联用, 合成一种新型两亲性接枝聚合物刷. 具有高环张力的降冰片烯单侧链大分子单体norbornene-graft-poly(ε-caprolactone)/Br (PCL- NBE-Br)首先进行ROMP反应, 生成聚合物主链, 每个单体单元上含有一条PCL链和一个溴官能团; 然后用含溴的ROMP聚合物poly(norbornene)-graft-poly(ε-caprolactone)/Br (PCL-PNBE-Br)作为大分子引发剂引发单体2-(dimethyl- amino)ethyl methacrylate)的ATRP反应, 生成结构明确的高密度两亲性接枝聚合物刷poly(norbornene)-graft-poly(ε- caprolactone)/poly(2-(dimethylamino)ethyl methacrylate) (PCL-PNBE-PDMAEMA), 其主链每个单体单元上均含有一条疏水性PCL接枝链和一条亲水性PDMAEMA接枝链. 最后, 研究此类高密度两亲性接枝聚合物刷的自组装行为, 用动态激光光散射(DLS)研究其在混合溶剂(THF/H2O)中的胶束行为, 考察胶束溶液的浓度以及不同长度的亲水性接枝链对胶束尺寸的影响; 利用透射电镜(TEM)观察胶束为球形, 具有类似线团或草莓状的形态.     

开环易位聚合聚双环戊二烯的合成及结构与性能的研究进展

开环易位聚合环烯烃已成为高分子工程领域的一个研究热点。其中,由于双环戊二烯（DCPD）价格低廉、来源充分、聚合后形成的聚双环戊二烯（PDCPD）具有优异的力学性能等优点,使得DCPD的开环易位聚合得到广泛关注。本文综述了DCPD开环易位聚合反应机理、催化体系、PDCPD的结构、PDCPD的表面改性、纳米共聚物以及PDC...     

面向本科生教学的开环聚合内容拓展

开环聚合作为与缩聚、加聚并列的第三大类聚合反应,具有如下特点:由于环状单体的特殊性,开环聚合反应无副产物生成;聚合物组成与单体的元素组成相同,即具有100%的原子利用率;大部分开环聚合反应具有连锁反应特征,链增长速度快;形成的聚合物链中含有杂原子,所得材料具有降解可控性。本文总结了近年来在开环聚合研究上的一些进展,如γ-丁内酯的开环聚合、活性开环聚合、易位开环聚合等,作为本科生《高分子化学》课程中"开环聚合"一章内容的有益补充。通过提供额外的一些参考文献来拓展本科生对前沿知识的了解,开阔优秀本科生的国际学术视野。     

Photoinduced Strain-Assisted Synthesis of a Stiff-Stilbene Polymer by Ring-Opening Metathesis Polymerization

Developing a novel strategy to synthesize photoresponsive polymers is of significance owing to their potential applications. We report a photoinduced strain-assisted synthesis of main-chain stiff-stilbene polymers by using ring-opening metathesis polymerization (ROMP), activating a macrocyclic π-bond connected to a stiff-stilbene photoswitch through a linker. Since the linker acts as an external constraint, the photoisomerization to the E-form leads to the stiff-stilbene being strained and thus reactive to ROMP. The photoisomerization of Z-form to E-form was investigated using time-dependent NMR studies and UV/Vis spectroscopy. The DFT calculation showed that the E-form was less stable due to a lack of planarity. By the internal strain developed due to the linker constraint through photoisomerization, the E-form underwent ROMP by a second generation Grubbs catalyst. In contrast, Z-form did not undergo polymerization under similar conditions. The MALDI-TOF spectrum of E-form after polymerization showed the presence of oligomers of >5.2 kDa.     

A Facile,Controlled Synthesis of Soluble Star Polymers Containing a Sugar Residue by Ring-Opening Metathesis Polymerization (ROMP)

Summary: Precise syntheses of soluble star polymers containing a sugar residue could be attained by adopting sequential ring-opening metathesis polymerizations of norbornene, 1,4,4a,5,8,8a-hexahydro-1,4,5,8-exo-endo-dimethanonaphtalene, and then 1,2:3,4-di-O-isopropylidene-α-D-galacto-pyranos-6-O-yl 5-norbornene-2-carboxylate using Mo(CHCMe₂Ph)(N-2,6-ⁱPr₂C₆H₃)(O^tBu)₂. The resultant polymers possessed uniform molecular weight distributions, and the M_n values could be varied by the monomer/Mo molar ratios; their spherical images were observed in the TEM micrographs.     

含负氢配体的单核钌催化的降冰片烯开环易位聚合催化研究

设计的含负氢配体的单核钌配合物Ru(p-cymene)HClPCy₃高活性地催化了降冰片烯开环易位聚合反应(ROMP), 并通过设计的Ru(p-cymene)H₂PCy₃对降冰片烯的催化活性研究证明了单核催化剂需同时含有氯原子配体, 提出了反应机理.     

Heterotelechelic Polymers by Ring‐Opening Metathesis and Regioselective Chain Transfer

Heterotelechelic polymers were synthesized by a kinetic telechelic ring‐opening metathesis polymerization method relying on the regioselective cross‐metathesis of the propagating Grubbs’ first‐generation catalyst with cinnamyl alcohol derivatives. This procedure allowed the synthesis of hetero‐bis‐end‐functional polymers in a one‐pot setup. The molecular weight of the polymers could be controlled by varying the ratio between cinnamyl alcohol derivatives and monomer. The end functional groups can be changed using different aromatically substituted cinnamyl alcohol derivatives. Different monomers were investigated and the presence of the functional groups was shown by NMR spectroscopy and MALDI‐ToF mass spectrometry. Labeling experiments with dyes were conducted to demonstrate the orthogonal addressability of both chain ends of the heterotelechelic polymers obtained.     

Ring-Opening Metathesis Polymerization of Cyclooctyne Employing Well-Defined Tungsten Alkylidyne Complexes

Summary: The ring-opening metathesis polymerization of cyclooctyne was studied was studied in the presence of catalytic amounts of the tungsten alkylidyne complexes [RCW(NIm^tBu){OCMe(CF₃)₂}₂] ( 1a: R = CMe₃, 1b: R = Ph). The resulting polymers show relatively narrow polydispersities with the PDI ranging from 1.2 to 2.4. Treatment of 1b with cyclooctyne in dilute toluene or hexane solution afforded only low molecular weight oligomers. The mass spectra of these oligomers indicate the existence of macrocycles of the formula [C(CH₂)₆C]_n (n = 3–9). In contrast, reactions at high substrate concentration led to mixtures of cyclic oligomers and linear polymers, which is probably a result of ring-chain equilibria, established in agreement with the Jacobson-Stockmayer theory of macrocyclization. In contrast, treatment of neat cyclooctyne with a catalytic amount of the catalyst produced medium molecular weight polymers in good yields.