有机硅合成新方法

有机硅材料作为一类具有独特优异性能的新材料,已成为化学和材料领域的重点研究方向之一。本文综述了近年来国内外有机硅合成的新方法,主要包括炔基-叠氮环加成反应、巯基-双键反应和胺-烯迈克尔加成反应等,重点介绍各种合成方法的优势及在制备新型功能化的有机硅化合物、有机硅聚合物及有机硅弹性体等中的应用,并对未来有机硅合成方法的发展方向进行了展望。     

环氧树脂增韧改性的研究进展

环氧树脂作为主要的热固性树脂之一,性能优异,应用广泛。但由于其固化交联密度高,脆性大的缺点,环氧树脂的实际应用受到了极大地限制。因此,环氧树脂的增韧改性成为了人们研究的重点。本文主要从橡胶、聚硅氧烷、热塑性塑料、树枝状聚合物、嵌段聚合物、纳米填料这几种主要增韧材料出发,系统综述了近几年来环氧树脂增韧改性的研究进展,简要阐述了各种材料的增韧机制,并对环氧树脂增韧改性的研究进行了分析与展望。     

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。     

有机硅改性有机合成树脂的研究状况

有机硅聚合物具有优异的耐候性、耐玷污性和耐高低温性,高度的疏水性,良好的透气性等被广泛应用.各种有机合成树脂有各自的优点和缺点,它们的缺点正好是有机硅聚合物的优点.将有机硅引入有机合成树脂,利用有机硅优点改进有机合成树脂的不足,使有机硅和有机合成树脂的性能更加完善,这对有机硅和有机合成树脂工业发展具有重大的意义.因此有机硅改性有机树脂是近年来研究的热点.本文简单综述了几种有机硅化学改性有机合成树脂的性能特点、制备方法及研究发展状况.     

聚氨酯改性环氧树脂的研究进展

环氧树脂具有优异的粘接性能和力学性能因而被广泛应用,但其耐热性差、脆性大等缺陷限制了其在高性能领域中的应用。聚氨酯具有高弹性、耐磨、抗撕裂等特点,且与环氧树脂相容性好。因此,利用聚氨酯改性环氧树脂能显著提高其力学性能,实现环氧树脂在众多领域的应用。本文综述了不同类型的聚氨酯改性环氧树脂的进展,指出了不同类型的聚氨酯改性环氧树脂的机理、改性效果及影响因素,并对其发展前景进行展望。     

环氧树脂在热塑性树脂改性中的应用

本文综述了国内外有关利用环氧树脂改性热塑性树脂共混体系研究的最新进展。着重阐述了环氧树脂在热塑性树脂之间的增容作用,如尼龙6(PA6)合金体系,改性聚苯乙烯塑料(ABS)合金体系,以及聚对苯二甲酸丙二醇酯(PTT)合金体系等。同时,介绍了利用环氧树脂的反应活性提高无机填料在聚合物中分散性研究的情况,如二氧化硅纳米粒子在聚醚砜(PES)中,以及滑石粉在聚丙烯(PP)中分散性的提高。最后,简介了环氧树脂改性热塑性树脂提高热塑性树脂物理机械性能方面的研究方向和成果并展望了环氧树脂在热塑性树脂改性研究中的前景。     

生物高分子黄原胶的性能、应用与功能化

讨论了黄原胶生物大分子的结构与性能关系，从有关黄原胶的性能、开发应用以及在抗菌素药物负载与控择、分散稳定与防腐作用，及其与有机硅化合物配伍制备消泡表面活性材料等，进行功能化改性方面，综述了近20年来国内外研究状况，并探讨了开展生物高分子黄原胶应用与开发研究的思路。     

功率型LED封装用高分子材料的研究进展

随着发光二极管(LED)亮度和功率的不断提高,封装材料已成为制约LED进入照明领域的关键技术之一。对于功率型LED封装材料,要求具有高折射率、高透光率、高导热率、耐紫外、耐热老化、低应力、低吸水率等性能特点。目前LED封装用两大主要高分子材料是环氧树脂和有机硅复合材料。对这两种材料的改性主要集中在折射率、耐老化性、导热性、吸水性和力学性能等方面。脂环族环氧树脂及纳米有机硅复合材料作为高功率LED封装材料具有广阔的发展前景。     

利用点击化学制备有机硅材料及应用

有机硅材料因其特殊结构和性能已成为材料科学研究领域的热点之一,点击化学以其反应条件温和、高效、易于进行且无副产物和高产率等优点受到化学家的广泛关注.本文综述了近年来点击化学在有机硅材料合成中的研究成果,重点介绍了利用点击化学对有机硅化合物的功能化,有机硅两亲性聚合物及有机硅弹性体的合成及在生物医学和光电材料等方面的应用,并对点击化学在新型材料领域中的应用及其发展方向进行了展望.     

有机硅改性UV固化水性环氧树脂的研究

以环氧树脂E-51、甲基三乙氧基硅烷为原料,用接枝共聚的方法合成了有机硅改性水溶性UV固化环氧树脂,该方法有效地改善了环氧树脂的柔韧性、水溶解性,提高了成膜物的机械性能,其拉伸强度达到53.5 MPa,断裂伸长率为46.5%,耐冲击性大于50 kg/cm。通过红外光谱、热重分析表征产物的结构和性能,结果表明,有机硅已经成功接枝到环氧树脂的分子上。有机硅改性后环氧树脂在400℃的分解率由之前的60%降至40%。文章同时讨论了有机硅改性水性UV固化环氧树脂合成中反应温度、有机硅种类以及加入量等对UV固化水性环氧树脂成膜物的附着力、耐水性及耐碱性的影响,以此获得最佳反应条件:质量分数为14.4%的甲基三乙氧基硅烷与羧酸改性的环氧树脂在90℃下反应5～6 h。     

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.