超支化聚(酯-胺)分子结构及固化涂层性能研究

近年来,颜德岳等基于A2型单体二丙烯酸酯及BB2′型单体二胺化合物合成了多种端胺基超支化聚(酯-胺),并对反应机理及聚合物结构进行了系统研究[1,2],结果表明,由于B与B′活性差异,反应首先生成AB2′型和B4′型中间体,进一步聚合得到可溶性产物.我们基于A3型单体三丙烯酸酯与B2型单体二胺化合物合成了端丙烯酸酯基超支化聚(酯-胺)[3,4].在这些体系中,由于官能团反应活性高,难以控制反应程度.另外,由于超支化聚合物不能直接用作结构材料,其在涂料、粘合剂等领域的应用多基于末端官能团的固化反应[5].但通常由于官能团在分子表面密集分布,部…     

超支化聚合物制备方法的研究进展

超支化聚合物是一类可以通过一步法来合成的具有高度支化结构的体型大分子.经过二十年的研究,超支化聚合物由于其独特的结构和性能特点以及可实现规模化生产的特点, 已经迅速成为一类重要的和具有广阔应用潜力的高分子材料.本文从单体类型的角度介绍了超支化聚合物的主要制备方法及其发展历程,主要涉及ABx型,AB*型,A2 B3型以及潜在ABx型单体(包括开环聚合和偶合单体法)等,同时论述了各制备方法的优点和局限性 .     

A_2+B_3型超支化芳香-脂肪型聚酰胺的合成及其表征

利用溶液聚合方法,以4,4′-二胺基二苯甲烷与氨三乙酸为原料,制备了A2+B3型超支化半芳香型聚酰胺(HPMDA),讨论了反应温度、反应时间、芳香二胺与氨三乙酸单体比例、单体浓度、催化剂及活化剂对反应的影响,发现了临界凝胶条件。利用傅立叶变换红外光谱(FTIR)、1H核磁共振谱(1HNMR)对制备的超支化半芳香型聚酰胺进行了结构表征。用乌式粘度计、热重分析(TG)测定了超支化半芳香型聚酰胺的粘度和热稳定性,并从微观反应机理和拓扑结构的角度,研究了反应条件对聚合物特性粘度的影响。     

超支化聚(酯-酰胺)的合成与流变改性研究

近十几年来 ,超支化聚合物因具有独特的结构和特殊的性能而受到普遍关注[1] .超支化聚合物具有低的熔体粘度 ,与线性聚合物共混可显著改善其加工流变性 ,具有商业应用潜力 .关于超支化聚合物在流变改性方面的应用已有文献报道[2～ 6] ,但目前文献中的大多数单体合成较繁琐且收率不高 ,这已成为制约超支化聚合物应用的瓶颈 ,如何以简便的途径合成超支化聚合物已成为当前研究的重点 .本文设计一条新的合成路线 ,即以 1 ,2 ,4 苯三酸酐、乙醇胺及乙酸酐为原料 ,以高的收率得到了单体N ( 2 乙酰氧基乙基 ) N ( 2′ ,4′ 二羧基苯甲酰基 )胺 (…     

新型双功能性超支化聚合物的制备及表征

首先以烯丙基缩水甘油醚与N-氨乙基哌嗪反应合成新型B3单体,然后分别以六亚甲基二异氰酸酯和1,6-己二硫醇为A2单体与上述B3单体反应,利用异氰酸-羟基以及巯基-烯的反应,合成了同时含有羟基和烯丙基的双功能性超支化聚(氨酯-胺)和聚(硫醚-胺)。研究了单体种类及投料比与合成的超支化聚合物的化学与拓扑结构的关系。通过红外吸收光谱、核磁共振氢谱和凝胶渗透色谱表征了超支化聚合物的分子结构和化学组成。结果表明:该B3单体同时带有3个羟基与3个烯丙基,当A2和B3单体投料比(物质的量之比)为0.825∶1时,可以成功制备较高分子量的双功能性超支化聚合物。     

超支化聚硅氧基硅烷的合成及其表征

基于线性聚硅氧烷在国防、能源和化工等领域的广泛应用,具有新颖拓扑结构和大量功能性端基的超支化聚硅氧烷引起了国内外科学工作者的广泛兴趣[1~7].到目前为止,主要是采用水解缩聚的方法合成超支化单体,在铂系催化剂存在下进行硅氢加成反应或者在碱催化剂存在下进行质子转移聚合制备超支化聚合物[8~12].然而,以上合成超支化聚硅氧烷的方法仍然存在一定的不足.例如,水解法步骤繁琐,通常在第一步反应结束后需要多次除水,并继续滴加单氯硅烷以得到完全取代的大单体;同时多官能度单体容易水解自缩聚,产生A2B4或A3B6等副产物,不仅不利于结构控…     

可紫外光固化的超支化聚硅氧烷合成及固化研究

同线型聚硅氧烷聚合物相比，超支化聚硅氧烷聚合物具有低粘度、高反应活性和良好的相容性等特点，其中以制备超支化的聚硅氧烷基硅氧烷和聚烷氧基硅氧烷为主．对于超支化聚硅氧烷主要是以ABx（X=2～6）（其中A为双键，B为硅氢键）型单体为原料，在氯铂酸或Pt／C的催化下，通过硅氢加成反应一步制备，最终聚合物的端基（B）为硅氢键，而双键则完全反应，此外也可通过含不同数目烷氧基硅烷的水解缩合制备超支化聚硅氧烷．     

可光固化超支化聚硅氧基硅烷的合成与表征

自20世纪80年代末期Kim和Webster首次采用AB2型单体合成超支化聚合物以来，超支化聚合物以其新颖的结构、独特的性能和广泛的应用前景受到了科学界和工业界的广泛关注．其中超支化有机硅聚合物，尤其是硅氧基聚合物，由于具有良好的高低温稳定性、耐腐蚀性、耐候性等，以及硅氯、硅氢等末端基团易于功能化改性的特点，使其在功能性涂层材料、催化剂以及液晶材料等领域具有重要的应用价值．到目前为止，有关超支化聚硅氧基硅烷的研究主要集中在AB2型单体（x≥2，A和B分别为硅氢基团和乙烯基、烯丙基等不饱和基团）的制备以及硅氢加成产物的功能化改性方面．     

基于炔类单体的点击聚合制备超支化聚合物

超支化聚合物由于其独特的树枝状结构和物理化学性质,已经得到了广泛关注及应用.而基于炔类单体的点击聚合作为一类简单、高效的聚合反应已被广泛用于超支化聚合物的制备.本文对近5年利用叠氮-炔和巯基-炔点击聚合制备超支化聚合物的工作进行了简要综述.其中,Cu(I)催化的叠氮-炔点击聚合可制备1?4-立构规整的超支化聚三唑;Ru(II)催化的叠氮-炔点击聚合可制备1?5-立构规整的超支化聚三唑;活化的炔类单体和叠氮单体的无金属催化点击聚合可得到1?4-异构体含量高(高达91.7%)的超支化聚合物;而光引发?热引发及自发的巯基-炔点击聚合可制备含硫的超支化聚合物.此外,对所制备的超支化聚合物的功能和应用进行了简单介绍,最后还简单讨论了点击聚合制备超支化聚合物方面的可能发展方向.     

由苯-1，2，4-三羧酸-1，2—酐和羟乙基哌嗪合成酰胺键、叔氨和酯键交替排列的水溶性超支化聚合物

基于官能团非等活性原理，由商品化多组分单体一步法合成了超支化聚合物． 用苯—1，2，4-三羧酸—1，2酐(BTAA)与羟乙基哌嗪(HEPZ)为原料，利用氨基和羟 基反应活性不同，制备了结构非对称超支化聚酰胺—酯．分别用红外、核磁共振确 定了所得聚合物的结构．该聚合物分子骨架中含有交替排列的酰胺键、叔氨和酯键 ，易溶于水．本合成方法原料易得、工艺简单，适合大量制备超支化聚合物．     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.