丙烯酸酯共聚物乳液自交联反应的研究

本文研究了含环氧基的丙烯酸酯四元共聚物乳液交联后的溶胀度、自交联反应及动力学.结果表明:交联共聚物的溶胀度Q随甲基丙烯酸环氧丙酯单体含量的增加而降低,共聚物在受热的情况下,环氧基因在羧基的作用下开环而发生交联反应,产生网状结构.     

Fe-Al-α,α'-联吡啶催化体系催化邻苯二甲酸酐与环氧环己烷开环共聚反应

 用Fe（acac）3－Al（i－Bu）3－α，α′－dipy（acac乙酰丙\r\n酮，dipy联吡啶）催化邻苯二甲酸酐与环氧环己烷开环交替共聚反应，\r\n研究了Fe／Al，Fe／α，α′－dipy摩尔比对聚合反应的影响．用核磁\r\n共振技术研究了共聚物的交替度，测得了共聚物中邻苯二甲酸酐含量达\r\n31％以上．用凝胶渗透色谱仪测得了共聚物的分子量．结果表明，共聚\r\n物分子量的分散度很窄．共聚反应动力学研究结果表明，共聚对单体的\r\n浓度呈一级反应，表观活化能为36．1kJ／mol．     

戊二酸锌催化环氧丙烷与马来酸酐开环共聚反应

以戊二酸锌为催化剂,在无溶剂条件下催化环氧丙烷与马来酸酐的开环共聚反应;优化了聚合条件,利用红外光谱和核磁共振谱研究了共聚物的结构,利用凝胶渗透色谱测定了其分子量.结果表明,戊二酸锌可以有效地催化马来酸酐与环氧丙烷的开环共聚,从而以较高转化率得到交替度较高的共聚物.     

酶促缩聚和原子转移自由基聚合法合成AB型两亲性嵌段共聚物

Novozyme-435催化10-羟基癸酸进行自缩聚反应得到线性聚酯, 端基分别是羟基(—OH)和羧基(—COOH), 在三乙胺催化下, 分别用α-溴代丙酰溴和三甲基氯硅烷(TMSCL)进行端基官能化生成一个单官能度的大分子引发剂, 在CuCl/2,2'-联吡啶(bpy)催化体系中, 引发甲基丙烯酸环氧丙酯(GMA)的原子转移自由基反应(ATRP), 得到聚(10-羟基癸酸酯)/聚甲基丙烯酸环氧丙酯(PHDA-b-PGMA) AB 型两亲性嵌段共聚物, 其结构及分子量(分布)通过核磁共振和凝胶渗透色谱(GPC)确证. 此AB型两亲性嵌段共聚物在水溶液中能自组装形成纳米粒子, 用原子力显微镜(AFM)观察粒子的形状和大小.     

环氧化天然橡胶二次改性的研究进展

环氧化天然橡胶(ENR)分子链中存在易开环的反应性环氧基团,环氧基团的开环反应为ENR进行进一步的改性提供了极大的方便。ENR选择性氢化双键可以提高其抗热氧稳定性;ENR与胺类化合物和含磷化合物的反应,可以将防老剂和阻燃剂负载到ENR分子链上,从而达到在分子尺寸的分散;可以利用环氧基团的选择性氧化裂解制备NR基嵌段共聚物的前驱体遥爪型NR;通过环氧基团可以进行接枝改性其它聚合物;此外,分子链中的环氧基团使ENR与无机填料和其它极性聚合物共混相容性提高。     

环氧基活化凝胶的开环反应

由自制的乙酸乙烯酯－甲基丙烯酸缩水甘油酯－甲基丙烯丙酯大孔共聚物与氨水反应，实现了环氧基的开环反应。考查了不同的氨水浓度、反应温度和时间对胺化转化率的影响，并测定了形成的伯胺基的ｐＫａ值为６．９。开环反应最适条件为：每克干树脂加入１．３ｍＬ的１３ｍｏｌ／Ｌ的氨水６０℃反应３ｈ以上，转化率达到６０％。     

二茂铁基嵌段共聚物制备及自组装研究

本文综述了近年来二茂铁基嵌段共聚物制备及自组装的研究进展.对环状二茂铁单体的活性阴离子引发开环聚合(ROP)、过渡金属催化开环聚合(ROP)及聚合机理和聚合物自组装胶束的结构、表征和潜在应用作了介绍.     

含不同季铵盐结构的新型水显影感光树脂

通过不同的三乙胺盐及丙烯酸对环氧酚醛树脂的开环反应,合成了含不同季铵盐及丙烯酸酯基的新型水显影感光树脂。研究了环氧基在不同三乙胺盐开环时的转化率,产物溶解性,感光性及热稳定性等。     

手性Salen及Ga(Salen)催化苯基锂对环氧环己烷对映选择性开环反应

合成了14个含1,2-环己二胺、1,2-二苯基乙二胺或邻苯二胺的手性Salen化合物, 研究了手性Salen直接催化苯基锂对环氧环己烷的不对称开环反应, 结果表明二胺的结构和苯环上3,3'-位取代基对反应的对映选择性有很大的影响. 用Salen与 Me₃Ga原位生成的Ga(Salen)催化苯基锂对环氧环己烷的不对称开环反应, 与用Salen直接催化相比, 得到了更好的化学产率和对映选择性. 当用Ga(Slane) 15为催化剂时, 最佳ee值为73%.     

用芘标记荧光研究苯乙烯／二乙烯苯交联凝胶的微环境性质

本文研究了一系列芘甲酰基标记的苯乙烯—二乙烯苯共聚物的荧光光谱，发现其光谱特征对共聚物中芘甲酰基的含量，溶胀作用以及溶胀溶剂的性质有明显的依赖性．这一结果可以用芘甲酰基在共聚凝胶中形成激基缔合物和激基复合物予以解释．     

改性生物凝胶对重金属离子的吸附性能研究

以桔子汁加工残渣为原料,制备钙型和氢型生物凝胶作为吸附剂,用于去除水溶液中的重金属离子.结果表明,上述凝胶在水溶液中稳定性较好,对重金属离子的吸附性能优良.钙型凝胶的吸附选择性顺序为:Fe3 ＞Pb2 ＞Cd2 ＞Zn2 ,饱和吸附容量分别为:Pb2 、Cd2 、Zn2 均为约1.1mmol/g、Fe3 为1.5mmol/g;氢型凝胶的吸附选择性顺序为:Pb2 ＞Zn2 ＞Cd2 .钙型凝胶对Fe3 的吸附行为明显不同于氢型凝胶,钙型凝胶以离子交换机理以及Fe3 与Ca2 之间的共沉淀作用为主;而氢型凝胶对Fe3 的吸附则以离子交换机理为主.     

聚合物微球固载的催化剂TEMPO在分子氧氧化环己醇过程中的催化特性

醇氧化为羰基化合物是有机合成工业中最重要的化学转变之一,在实验室研究和精细化工生产中都占有非常重要的地位.使用传统的化学计量强氧化剂(如CrO3, KMnO4, MnO2等),不但成本高及反应条件苛刻,还会产生大量污染环境的废弃物.因此,需要大力发展高效、绿色化的醇转变为羰基化合物的氧化途径.以2,2,6,6-四甲基哌啶氮氧自由基(TEMPO)为催化剂,分子氧为氧化剂,可在温和条件下绿色化地实现醇的氧化转变.该催化氧化作用的实质是TEMPO经过单电子氧化过程转化为相应的氮羰基阳离子,该阳离子是一个具有强氧化性的氧化剂,可将伯醇和仲醇分别快速地、高转化率、高选择性地氧化为对应的醛或酮.然而,目前使用的TEMPO大多为均相催化剂,虽然表现出良好的催化活性和选择性,但反应后难以分离回收,不能再循环使用,严重制约着这一催化体系的发展.本文将TEMPO化学键合在聚合物载体上,在非均相催化剂的作用下,以期实现环已醇的分子氧氧化,将其转变为环已酮.首先采用悬浮聚合法,制备了交联聚甲基丙烯酸缩水甘油酯(CPGMA)微球,该聚合物微球表面含有大量环氧基团,为实现TEMPO的固载化提供了条件.以4-羟基-2,2,6,6-四甲基哌啶氮氧自由基(4-OH-TEMPO)为试剂,使CPGMA微球表面的环氧基团发生开环反应,从而将TEMPO键合于微球表面,制得了固载有TEMPO的聚合物微球TEMPO/CPGMA.将此非均相催化剂与Fe(NO3)3组成共催化体系,应用于分子氧氧化环己醇的催化氧化过程,深入考察了该共催化体系的催化性能,并探索研究了催化氧化机理,考察了主要条件对催化氧化反应的影响.结果表明,共催化体系TEMPO/CPGMA+Fe(NO3)3可以有效地催化分子氧氧化环己醇的氧化过程,将环己醇转化为唯一的产物环己酮,显示出良好的催化选择性.助催化剂Fe(NO3)3化学结构中的Fe3+离子和NO3–离子两种物种均参与催化过程,共同发挥助催化剂的作用,伴随着两种价态铁物种Fe(Ⅱ)与Fe(Ⅲ)的转变以及NO3–与NO2–之间的转变,固载化的氮氧自由基TEMPO不断地转变为氮羰基阳离子,该氧化剂物种使环己醇的氧化反应不断地循环进行.对于共催化体系TEMPO/CPGMA+Fe(NO3)3的使用,适宜的反应条件为TEMPO与Fe(NO3)3的摩尔比为1：1,55°C,通入常压O2.反应35 h,环己酮的转化率可达到44.1%.因此,在温和条件下,使用固载化的TEMPO,有效地实现了环己醇向环己酮的转化.此外,固载化催化剂TEMPO/CPGMA在循环使用过程中表现出良好的重复使用性能.     

Effect of ring annelation on cations [M = H+, Li+, Na+, K+, Be2+, Mg2+, and Ca2+]…benzene interaction: A density functional theory investigation

Density functional theory calculation was carried out on cation‐π complexes formed by cations [M = H⁺, Li⁺, Na⁺, K⁺, Be²⁺, Mg²⁺, and Ca²⁺] and π systems of annelated benzene. The cation‐π bonding energy of Be²⁺ or Mg²⁺ with annelated benzene is very strong in comparison with the common cation‐π intermolecular interaction, and the bonding energies follow the order Be²⁺ > Mg²⁺ > Ca²⁺ > Li⁺ > Na⁺ > K⁺. Similarly, the interaction energies follow the trend 1‐M < 2‐M < 3‐M for all the metal cations considered. These outcomes may be due to the weak interactions of the metal cations with C? H and the interactions of metal cations with π in addition to the nature of a metal cation. We have also investigated on all the possible substituted sites, and find that the metal ion tends to interact with all ring atoms while proton prefers to bind covalently to one of the ring carbons. The binding of metal cations with annelated benzenes has striking effect on nuclear magnetic resonance chemical shifts using the gauge independent atomic orbital method. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009     

Solvent Extraction of Alkali Metal Picrates by Lipophilic Cyclodextrin Derivatives

Lipophilic cyclodextrin (CD) derivatives were prepared to extract alkali metal cations from a water phase into an organic phase. The extraction equilibrium constant, K ex, was determined by the solvent extraction method using UV absorption spectroscopy. Hydroxyl groups at the carbons in the 2,6-positions of CD molecules were dipropylated to add the hydrophobicity for dissolving into organic solvents, and furthermore hydroxyl groups at the carbons in the 3-position of these derivatives were acylated as complexing sites with the alkali metal cations. These CD derivatives formed a 1 : 1 complex with alkali metal cations, except for the case of Li+, and transported the alkali metal cations from a water phase into a benzene phase. The initial concentrations of alkali metal cation and picrate anion in the water phase and that of the CD derivatives in the organic phase strongly influenced the extraction equilibrium. Extraction of the alkali metal cation by the derivative without acyl groups was not detected. K ex values of these CD derivatives are of the same order of magnitude as or larger than those of crown ethers. The order of the K ex values in all cases is Li+ < Na+ < K+ Rb+ Cs+, although these CD derivatives have no special selectivity for the alkali metal cations. The cation extraction mechanism was interpreted by an induced-fit mechanism.     

Hyperbranched block copolymer from AB2 macromonomer: Synthesis and its reaction‐induced microphase separation in epoxy thermosets

In this contribution, we reported the synthesis of a hyperbranched block copolymer composed of poly(ε‐caprolactone) (PCL) and polystyrene (PS) subchains. Toward this end, we first synthesized an α‐alkynyl‐ and ω,ω′‐diazido‐terminated PCL‐b‐(PS)₂ macromonomer via the combination of ring‐opening polymerization and atom transfer radical polymerization. By the use of this AB₂ macromonomer, the hyperbranched block copolymer (h‐[PCL‐b‐(PS)₂]) was synthesized via a copper‐catalyzed Huisgen 1,3‐dipolar cycloaddition (i.e., click reaction) polymerization. The hyperbranched block copolymer was characterized by means of ¹H nuclear magnetic resonance spectroscopy and gel permeation chromatography. Both differential scanning calorimetry and atomic force microscopy showed that the hyperbranched block copolymer was microphase‐separated in bulk. While this hyperbranched block copolymer was incorporated into epoxy, the nanostructured thermosets were successfully obtained; the formation of the nanophases in epoxy followed reaction‐induced microphase separation mechanism as evidenced by atomic force microscopy, small angle X‐ray scattering, and dynamic mechanical thermal analysis. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 368–380     

离子交联聚氯乙烯的结构与性能

由氯乙烯/丙烯酸悬浮共聚合成了不同羧基含量的PVC树脂,采用溶液反应和熔融加工法制备离子交联PVC,对其结构和性能进行了研究.结果表明,共聚物中羧基主要以二聚体形式存在,用金属离子中和能形成部分络合结构;用Ca²⁺、Mg²⁺离子络合的羧基含量较高的VC/AA共聚物存在离子对聚集态结构;离子对含量、金属离子种类和增塑剂浓度影响离子聚集相的比例和稳定性,离子聚集具有热可逆性;离子交联使PVC的T_g、熔体粘度和回弹性提高.     

金属离子对RhCl（CO）（TPPTS）2催化1—己烯氢甲酰化反应的影响

在以水溶性铑－膦配合物为催化剂的烯烃氢甲酰化反应中,铑的存在形态及配位结构对烯烃氢甲酰化反应的转化率及选择性起着决定性的作用．在反应过程中,特别是工业生产过程中,会由于各种原因导致一些杂质进入反应体系,这些杂质可能会影响铑－膦配合物催化剂的性质,改变...     

Vibrational study of the salicylate interaction with metallic ions and surfaces

Infrared and Raman spectroscopy are used in this work to study the metallic complexes of salicylic acid with silver and copper, comparing the interaction between salicylate and the cations (Ag+ and Cu2+) in the metal complexes with the SERS spectra when adsorbed on colloidal metal surfaces of the same metals. The salicylate complexes with the above metals were compared to those of Na+, Fe3+ and Al3+ cations. A different interaction mechanism is deduced for salicylate in the metal complex and when adsorbed on the metal surface.     

Thin-layer chromatographic behavior of rare earths on silica gel with aqueous alkaline earth metal nitrate solutions as mobile phases

The TLC behavior of all the rare earths except Pm has been surveyed on silica gel (pH 7.0) pretreated with 0.1 mol L(-1) tris(hydroxymethyl)aminomethane and 0.1 mol L(-1) HCl with aqueous nitrate solutions of alkaline earth metals as mobile phases. The RF values of the lanthanides varied in a regular and characteristic way accompanied by the tetrad effect with increasing atomic number, and when the mobile phases were changed the RF values of each metal decreased in the order Mg2+ > Ca2+ > Sr2+ > Ba2+, as the crystal ionic radii of the alkaline earth metals increased. This adsorption sequence was not observed with alkali metal nitrate and alkali metal chloride mobile phases. A brief discussion concerning the effect on RF values of the solvent cations and the adsorption mechanism is included; also presented are typical chromatograms for the separation of multi-component mixtures containing adjacent lanthanides.     

壳聚糖缩合呋喃甲醛螯合树脂的合成及性能研究

利用壳聚糖C2 位上活泼氨基与呋喃甲醛缩合反应 ,合成了一种新型树脂。通过L9(34 )正交试验 ,研究了缩合反应的最佳条件 :80℃乙醇中溶胀 1h ,反应 5h ,pH =4.0～ 4.5 ,反应物配比 (氨基摩尔∶醛基摩尔 )为 1∶4,缩合率达到 90 %以上。并测定了上述螯合树脂对过渡金属离子的吸附性能。