自修复聚合物材料的研究进展

针对聚合物材料在使用过程中难以检测的损伤,人们引入了自修复概念。本文就近年来自修复聚合物材料的研究进展作了系统综述。根据自修复过程是否使用修复剂,聚合物材料(包括聚合物基复合材料)的自修复可分为外援型和本征型两大类。外援型自修复借助于外加修复剂实现自修复,主要包括埋植微胶囊化修复剂和埋植中空纤维化修复剂两种方法。微裂纹的破坏使微胶囊或中空纤维释放修复剂,修复剂发生化学反应,键合裂纹面,达到自修复的效果。这种方法相对比较简单,修复效果较好,但不能重复进行,而且可选用的修复剂种类有限。本征型自修复则借助于体系内存在的Diels-Alder反应、动态共价化学、双硫键反应、含有氢键的超分子结构、π-π堆叠及离子聚合物等来完成,这些特殊的分子结构所涉及的化学反应是可逆的。本征型自修复聚合物材料的制备过程较为复杂,但这种自修复可以反复多次有效,从而延长了聚合物材料的使用寿命。本文针对以上两大类自修复聚合物材料体系的特点和应用进行综述,并展望其发展方向。     

自愈合聚合物材料的研究进展Ⅱ.热塑性聚合物的自愈合机理

自愈合聚合物材料是受自我修复生物体系的触发而发展的,这是一个新兴迷人的研究领域,可以明显拓宽聚合物材料的工作寿命和广泛应用的安全性.文章是《自愈合聚合物材料的研究进展Ⅰ.传统修复方法及热固性自愈合材料的制备和表征》的续篇,进一步介绍可自我修复的热塑性高分子材料的愈合机理.     

基于Diels-Alder反应的自修复聚合物材料

Diels-Alder(DA)反应是一类二烯和亲二烯体进行的[4+2]环加成反应。基于DA反应及其逆过程的自修复聚合物材料近年来在形状记忆材料、可修复涂层、药物输送以及电子封装等领域取得广泛应用。DA反应制备自修复聚合物时通常使用含呋喃基团的化合物或低聚体作为二烯,马来酰亚胺化合物作为亲二烯体。其它的二烯-亲二烯体系如蒽-马来酰亚胺和环戊二烯-双环戊二烯等也被报道用来做自修复材料。本文根据二烯和亲二烯体的不同结构,综述了基于DA反应的自修复聚合物材料研究进展及应用,并探讨了其潜在发展方向。     

自愈合聚合物材料的研究进展Ⅰ.传统修复方法及热固性自愈合材料的制备和表征

自愈合聚合物材料是受自我修复生物体系的触发而发展的,这是一个新兴迷人的研究领域,可以明显拓宽聚合物材料的工作寿命和广泛应用的安全性.参考近年来的文献资料,文章着重介绍了传统的修复聚合物材料的方法,以及各种热固性自愈合材料的制备和表征,其中最主要的制备方法是中空纤维法和微胶囊法.     

基于聚合物复合物的自修复与可修复聚合物材料

聚合物材料在使用过程中受到损伤,就会丧失原有的力学强度和功能.修复功能能够延长聚合物材料的使用寿命、减少原料浪费并提高材料性能的可靠性.赋予聚合物材料修复性能是可持续发展社会对聚合物材料设计的重要需求.本文系统地介绍了本研究组发展的基于溶液中复合的聚合物复合物构筑自/可修复聚合物材料的方法,以及基于高密度的超分子可逆作用力及聚合物复合原位生成的纳米粒子的协同,解决聚合物复合材料的良好修复性能与高力学强度之间矛盾的策略.基于聚合物复合的方法,我们成功制备了聚合物凝胶、弹性体及高强度聚合物复合材料,并实现了上述修复材料在防雾、质子传导和传感等方面的功能.聚合物复合的方法为制备具有优异力学性能和功能的自/可修复聚合物材料提供了新思路.     

基于光化学反应制备的本征型自修复涂层研究进展

本文简要介绍了基于光化学反应制备的本征型自修复涂层研究进展,重点介绍了基于双硫键交换、基于Diels-Alder可逆反应、基于氢键作用、基于光二聚反应,以及基于自填充作用的自修复涂层,对涂层的制备方法、自修复机理及修复效率进行了简要阐述,并对基于光化学反应制备的本征型自修复涂层在未来的发展及应用进行了展望。     

基于非共价键的本征型自修复聚合物材料及其应用

自修复材料作为一种拥有结构上自愈合能力的智能材料近年来得到了快速发展。具备自修复性能的聚合物材料主要包括外援型和本征型。由于本征型自修复聚合物材料具有潜在的自修复能力,且能实现多次修复,所以该领域对于本征型自修复聚合物材料的关注越来越多。由氢键、π-π堆积、疏水作用、离子作用和主客体作用等非共价键力形成的本征型自修复聚合物体系不需要或需要极少外界能量就能实现快速、高效修复。这将是实现节约能源,社会可持续发展的重要途径。本文以不同类型的非共价键为线索,综述了近年来基于非共价键的本征型自修复聚合物材料的发展及其应用,并展望了其未来的发展方向。     

基于Diels-Alder反应的自修复聚氨酯的结构与修复行为

采用呋喃封端的聚氨酯预聚体与双马来酰亚胺反应,合成了基于Diels-Alder(DA)反应的热可逆自修复聚氨酯(PU-DA).利用FTIR、DSC和gel-solution-gel方法对其分子结构、热性能及其可逆性进行了表征,结果表明,具有热可逆性的DA键被成功引入到聚氨酯中,从而赋予聚氨酯具有良好的再加工性能和自修复性能.通过偏光显微镜观测对材料的自修复行为进行了考察,结果表明,由于DA反应的热可逆性,0.5 mm深度划痕的聚氨酯试样在120℃热处理300 s或130℃热处理150 s后划痕便可消失,从而实现了划痕的自修复.并且模拟实际生活中聚合物材料受到轻微损伤时的情况,通过拉伸试验对0.5 mm深度划痕有效自修复的热处理温度和时间进行了确定,并对同一受损部位多次刻划-修复的修复效率进行了详细研究,结果表明:在120℃处理15 min可达到最佳修复效果,其一次修复效率可达71%,同一受损部位经过3次刻划—修复后,其修复效率仍能达到35%.     

光响应超分子聚合物

超分子聚合物是超分子化学、高分子化学和材料化学领域的研究热点.将光响应的功能基团以非共价作用构筑到超分子聚合物体系中,得到光响应型超分子聚合物,从而能够将超分子聚合物的独特性质与光化学反应的优势有效地结合起来,从而构筑新型的光功能材料.本文总结了近年来本课题组有关光响应超分子聚合物方面的研究工作:介绍了主链型的光响应超分子聚合物的光调控组装和解离,超分子聚合物和共价聚合物的光控可逆切换和光调控组装形貌;另外还举例介绍了具有自修复和室温磷光发射等功能的侧链型光响应超分子聚合物,并对刺激-响应的超分子聚合物领域的发展做了展望.     

单体结构对基于离子作用的自修复光固化材料性能的影响

本文研究了单体结构及其比例对基于离子作用的自修复光固化材料光聚合行为、力学性能,以及自修复性能的影响。结果表明：改变软硬单体种类及其比例不会改变自修复光固化体系的光聚合行为。增加软单体含量和降低硬单体含量,材料的拉伸应变和修复效率随之增加,断裂应力随之降低。硬单体中刚性环会增加聚合物链间的内摩擦力,使材料断裂应力增加,软单体中柔性醚链则降低链间范德华力,增强链移动性,提高材料的拉伸应变和修复效率。软单体为丙烯酸正丁酯（BA）及硬单体为丙烯酸异冰片酯（IBOA）的样品IB7-BA3展现出较好的综合性能,断裂应力为1.42 MPa,拉伸应变为295%,修复效率高于90%。     

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.