共查询到18条相似文献,搜索用时 109 毫秒
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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 总被引:1,自引:0,他引:1
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。 相似文献
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用Grubbs第二代催化剂引发降冰片烯类单体(NBEDE)和链转移剂在离子液体[bmim][BF4]中的开环易位聚合(ROMP)反应,反应体系保持均相,无聚合物析出,得到两端为叔溴的遥爪型官能化聚合物(Br-PNBEDE-Br).以Br-PNBEDE-Br作为大分子引发剂,在离子液体介质中引发甲基丙烯酸2-(二甲氨基)乙酯(DMAEMA)的原子转移自由基聚合(ATRP),制得分子量分布较窄的两亲性三嵌段共聚物(PDMAEMA-PNBEDE-PDMAEMA).利用动态激光光散射(DLS),原子力显微镜(AFM),透射电镜(TEM)等技术,考察嵌段共聚物在选择性溶剂/共溶剂(H2O/THF)中的胶束行为,以及溶液pH值对胶束的影响.结果表明,TEM观察到胶束为球形,由于TEM和AFM是在干态下测得胶束的粒径,而DLS是在溶液中测定胶束的流体力学直径,所以TEM和AFM得到的胶束粒径小于DLS的结果.不同pH值对胶束尺寸大小有明显的影响,胶束微粒随着pH值的增大而增大. 相似文献
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有机磺酰氯存在下的自由基聚合(Radical polymerization,RP)具有反应条件温和、体系组成简单、单体适用范围较广的优点。本文主要概述了有机磺酰氯在自由基聚合中的应用,主要包括原子转移自由基聚合(Atom transfer radical polymerization,ATRP)的引发剂、单电子转移活性自由基聚合(Single-electron transfer living radical polymerization,SET-LRP)的引发剂和普通自由基聚合的链转移剂。并分析了以上三种应用单体的适用范围、有机磺酰氯结构与聚合活性的关系以及有机磺酰氯(多官能团有机磺酰氯引发剂和链转移单体)在聚合物分子设计中的应用。 相似文献
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可逆加成-断裂链转移(RAFT)聚合作为一种新型活性自由基聚合,由于其具有单体适用面广、操作条件温和、实施聚合的方法多--本体、溶液、乳液、悬浮聚合均可的优点已经在分子设计方面取得了广泛的应用.星形聚合物作为一种特殊结构的聚合物,由于其具有较低的结晶度、较小的流体动力学体积等独特的性质,越来越引起研究者的重视.本文综述了近几年来采用RAFT法合成星形聚合物的研究进展.根据合成星形聚合物所用的RAFT多官能团试剂种类,对RAFT法合成星形聚合物的反应进行了分类. 相似文献
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多肽是由α-氨基酸以肽键形式连接在一起而形成的天然聚合物,具有多种重要生物功能。α-氨基酸N-羧基环内酸酐(NCA)开环聚合是制备多肽聚合物最便捷的方法,被多个领域广泛应用。传统的NCA聚合对水分非常敏感,通常使用严格干燥溶剂并在手套箱中操作;NCA聚合反应速率一般很慢,而且NCA单体本身不稳定,长时间的聚合会导致副反应的产生,并难以获得高分子量多肽聚合物。这些长期未解决的难点阻碍了NCA聚合材料的发展。最近,华东理工大学刘润辉课题组报道了六甲基二硅基胺基锂(LiHMDS)引发的NCA开环聚合方法,此方法聚合速率快,对水分不敏感,可在敞口容器中聚合,摆脱了对手套箱的依赖;该NCA聚合可合成高分子量多肽聚合物,产物具有多肽特征性的二级结构;另外,LiHMDS引发的NCA开环聚合为活性聚合,可实现多肽聚合物的端基功能化。 相似文献
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Hisaki Otani Sakiko Fujita Yu Watanabe Michiya Fujiki Kotohiro Nomura 《Macromolecular Symposia》2010,293(1):53-57
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)(OtBu)2. The resultant polymers possessed uniform molecular weight distributions, and the Mn values could be varied by the monomer/Mo molar ratios; their spherical images were observed in the TEM micrographs. 相似文献
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Elif Baysak Ozgun Daglar Ufuk Saim Gunay Gurkan Hizal Umit Tunca Hakan Durmaz 《Journal of polymer science. Part A, Polymer chemistry》2018,56(19):2145-2153
Two different oxanorbornene monomers were prepared and copolymerized with butyl-functionalized oxanorbornene monomer through the ring-opening metathesis polymerization. The resulting polymers were then subjected to the aminolysis reactions with propylamine (PA) in the presence of methyl acrylate (MA) to capture, in situ, the latent thiol. It was found that the polymer, in which the thiolactone unit is close to the polymer backbone, did not undergo an efficient aminolysis reaction even an excess amount of PA was utilized, while the other polymer, in which the thiolactone unit away from the polymer backbone, did efficiently undergo aminolysis reaction even PA was used in low amounts. Besides, a variety of primary amine compounds along with MA were reacted with the polymer, in which the thiolactone group away from the polymer backbone, to test their reactivity toward the aminolysis reactions. All modified polymers were characterized by using conventional instruments such as gel permeation chromatography, nuclear magnetic resonance, and differential scanning calorimetry. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 2145–2153 相似文献
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Summary: The ring-opening metathesis polymerization of cyclooctyne was studied was studied in the presence of catalytic amounts of the tungsten alkylidyne complexes [RCW(NImtBu){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. 相似文献
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Dr. Baiju P. Krishnan Lulu Xue Xinhong Xiong Prof. Dr. Jiaxi Cui 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(65):14828-14832
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. 相似文献
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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。 相似文献
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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。 相似文献
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Summary: Imidazol(in)ium-2-carboxylates were used as N-heterocyclic carbene (NHC) ligand precursors to convert the [RuCl2(p-cymene)]2 dimer into three ruthenium-arene complexes of the [RuCl2(p-cymene)(NHC)] type. The decarboxylation of NHC · CO2 betaines also provided a convenient synthetic path to prepare five well-known ruthenium-NHC catalysts for olefin metathesis and related reactions, including the second generation Grubbs and Hoveyda–Grubbs catalysts, via ligand exchange with phosphine-containing, first generation ruthenium-benzylidene or indenylidene complexes. Both procedures are particularly attractive from a practical point of view, because NHC · CO2 adducts are stable zwitterionic compounds that can be stored and handled with no particular precautions. 相似文献