Synthesis of cross-linked poly(4-vinylpyridine) and its copolymer microgels using supercritical carbon dioxide: Application in the adsorption of copper(II)

Compared with conventional precipitation polymerization method, cross-linked poly(4-vinylpyridine) (P4VP) and its microgels copolymerized with α-methacrylic acid (MAA) were synthesized through a new route of stabilizer-free polymerization in supercritical fluids. The yellow, dry, fine powders were directly obtained from precipitation polymerization of 4-vinylpyridine in supercritical carbon dioxide (scCO₂) at pressures ranging from 70.0 to 230 bar, using N,N′-methylenebisacrylamide as cross-linker. The effects of the reaction pressure, cross-linker ratio, initiator concentration, and reaction time were investigated. The capacity of this microgel for adsorption of copper(II) was also studied. At higher cross-linker concentrations, a high yield of the cross-linked P4VP microgel was generated in scCO₂, and its particle size was less than 300 nm. Polymerization of cross-linked P4VP in scCO₂ was extremely sensitive to the density of the continuous phase. The adsorption followed the Langmuir isotherm. The adsorption capacities of cross-linked P(4VP-co-MAA) and cross-linked P4VP were 47.2 and 26.9 mg g⁻¹, respectively.     

Synthesis,characterization, and fluorescence of end‐functionalized polystyrene initiated by 4‐chloromethyl benzoic acid and ethyl 4‐chloromethyl benzenecarboxylate via ATRP

End‐functionalized polystyrene (PSt) was synthesized via atom‐transfer radical polymerization (ATRP) by using 4‐chloromethyl benzoic acid (CMBA) and the ethyl‐protected carboxylic acid, ethyl 4‐chloromethybenzenecarboxylate (ECBC), as initiators respectively. The structure of PSt proved the living‐radical polymerization. Results exhibit both ATRP initiators afforded well‐controlled polymerization with high initiator efficiencies. However, the study also shows the controllability of ATRP can be obviously influenced by using different initiator in different catalyst system. Furthermore, the terminal group of the PSt1, benzoic acid, can coordinate with Europium(III) ion to obtain the polymeric Eu(III) complex, which shows both emissions of polymer and Eu(III) ion. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

原子转移自由基聚合在树形聚合物合成中的应用

原子转移自由基聚合(ATRP)技术是一种新型的可控/活性聚合技术,可有效地对聚合物的分子结构进行设计,制备出各种不同性能、不同组成、不同功能化的结构确定的聚合物。综述了利用ATRP技术合成树枝状-线性嵌段共聚物、类树枝状聚合物(dendrimer-like polymer)、具有刺激-响应性末端基团的树枝状聚合物、树枝状-星型嵌段共聚物和基于树枝状聚合物的聚合物刷的研究进展。     

表面引发AGET ATRP原位聚合法制备Fe_3O_4/PGMA复合纳米粒子

以多元醇还原法制备亲水性超顺磁四氧化三铁(Fe3O4)纳米粒子,并利用表面引发电子活化再生原子转移自由基聚合(SI-AGET ATRP)法,制备了Fe3O4/聚甲基丙烯酸缩水甘油酯(Fe3O4/PGMA)磁性复合纳米粒子。研究了原位聚合过程中还原剂异辛酸亚锡(Sn(EH)2)用量对PGMA接枝量和复合纳米粒子磁性能的影响。结果表明:Sn(EH)2在0.005~0.03 mmol时,聚合物接枝量随着Sn(EH)2用量的增大而增加;当Sn(EH)2用量大于0.15 mmol时,PGMA接枝量先增大后减少。磁性能研究表明,复合纳米粒子在室温下具有超顺磁特性,其饱和磁化强度从改性前的Ms=73 emu?g?1降低到Ms=1 emu?g?1。     

In-situ IR Monitoring the Synthesis of Amphiphilic Copolymery P(HEMA-co-tBMA) via ARGET ATRP

The amphiphilic copolymer poly(hydroxyethyl methacrylate-co-tert-butyl methacrylate) [P(HEMA-co-tBMA)] was synthesized by activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP), with the synthesis process monitored by in-situ infrared spectroscopy (IR). The molecular weight, chemical structure and characteristics of the copolymer were determined by 1H NMR, gas chromatography and gel permeation chromatography. The influences of various parameters on the living polymerization were explored. The molecularweight of the copolymer with narrowmolecularweight distribution (M_w/M_n b 1.50) increases approximately linearly with the monomer conversion, indicating a good control of polymerization. In the reaction temperature range from 50℃ to 90℃, the monomer conversion is higher at 60℃. The tBMA conversion rate decreases gradually with the increase of tBMA content, while the HEMA conversion is hardly affected by HEMA content. Weak polar solvent is more favorable to the polymerization compared to polar solvent. The molar ratio of reducing agent to catalyst has significant effect on the polymerization and increasing the amount of reducing agent will accelerate the reaction rate but causes wider molecular weight distribution. It is indicated that in-situ IR monitoring contributes to a more in-depth understanding of the mechanism of methacrylate monomer copolymerization.     

Design and synthesis of near-IR luminescent mesoporous materials covalently linked with tris(8-hydroxyquinolinate)lanthanide(III) complexes

By using the bifunctional ligand, 8-hydroxyquinoline-functionalized organosilane (Q-Si), the new mesoporous material Q–MCM-41 covalently bonded with 8-hydroxyquinoline was synthesized. Through the ligand exchange reaction, the new near-infrared (NIR) luminescent mesoporous LnQ₃–MCM-41 (Ln = Er, Nd, Yb) materials were prepared by linking the lanthanide quinolinate complexes to the ordered mesoporous Q–MCM-41 material. The LnQ₃–MCM-41 materials were characterized by powder X-ray diffraction and N₂ adsorption/desorption, and they all show the characteristic mesoporous structure of MCM-41 with highly uniform pore size distributions. Fluorescence spectra of these LnQ₃–MCM-41 materials were recorded and the corresponding luminescence decay analyses were measured. After ligand-mediated excitation, all the emission spectra of the LnQ₃–MCM-41 materials show the characteristic NIR-luminescence of the corresponding lanthanide ions via the intramolecular energy transfer from the ligands to the lanthanide ions. The good luminescent performances enable these NIR-luminescent mesoporous materials to have potential applications in optical amplification (operating at 1.3 or 1.5 μm) and laser systems, etc.     

Synthesis by self-condensing AGET ATRP and solution properties of arborescent poly(sodium 2-acrylamido-2-methyl-N-propane sulfonate)

Randomly branched (arborescent) poly(sodium 2-acrylamido-2-methyl-N-propanesulfonates) (NaPAMPS) were synthesized via self-condensing vinyl polymerization using activators generated by electron transfer atom transfer radical polymerization (AGET ATRP). The controlled self-condensing AGET ATRP of NaAMPS was realized in the presence of 2-(2-bromopropionyloxy)ethyl acrylate (BPEA) as a branching monomer (inimer) in water/pyridine (35-50% of Py) mixed solvents. The content of BPEA in the reaction feed was varied from 10 to 30 wt% allowing the synthesis of NaPAMPS with different degree of branching. SEC determined molecular weight of the prepared NaPAMPS was M_w = 94 000-120 000 g/mol, and the accompanying polydispersity index PDI ranged from 1.84 to 2.47. The definite evidence of highly branched structure of NaPAMPS was provided by the dependence of radius of gyration R_g on weight-average molecular weight M_w with characteristic slope a = 0.38-0.42, and by small-angle X-ray scattering (SAXS) analysis. Molecular parameters, conformation and dynamics of the branched NaPAMPS in dilute salt-free solutions and in the presence of a salt were elucidated by static and dynamic light scattering and SAXS.     

功能离子液体[N4MIM]Cl的合成及其配合Cu 催化ATRP反应研究

以N-甲基咪唑为骨架引入1,2-二氯乙烷合成中间体氯化1-氯乙基-3-甲基咪唑([CeMIM]Cl),再与三乙烯四胺反应合成了氯化1-（三乙基四氨基）乙基-3-甲基咪唑离子液体（[N4MIM]Cl）。通过红外光谱IR、核磁共振氢谱1HNMR对[N4MIM]Cl进行分析测试,确证了[N4MIM]Cl的化学结构。通过循环伏安法测得[N4MIM]Cl具有较低的氧化还原电势,E1,2为-0.472V,与有机配体相比[N4MIM]Cl具有较好的配位性能。将[N4MIM]Cl与CuBr配位用于催化氯化1-烯丙基-3-甲基咪唑离子液体（[AMIM]Cl）体系中甲基丙烯酸甲酯（MMA）的原子转移自由基聚合（ATRP）反应,经凝胶渗透色谱法（GPC）测试证明[N4MIM]Cl对ATRP反应具有较好的可控性。原子吸收光谱（AAS）测定聚合产物聚甲基丙烯酸甲酯（PMMA）中Cu2 的残留量仅为360mg穔g-1,表明与传统有机配体相比,[N4MIM]Cl有利于催化剂与聚合产物的分离。     

Synthesis, structures, and photoluminescent properties of 3D lanthanide coordination polymers with rare (4,5)-connected topology

Three lanthanide coordination polymers, [Ln(Hpdc)(ox)_0.5(H₂O)₂]·H₂O (Ln = Nd(1), Eu(2), Er(3)) (H₃pdc = 3,5-pyrazoledicarboxylic acid, ox = oxalate), have been synthesized by the hydrothermal reaction of lanthanide nitrates, 3,5-pyrazoledicarboxylic acid, and oxalic acid (H₂ox) and characterized by elemental analysis, IR, and single-crystal X-ray diffraction. Single-crystal X-ray diffraction studies indicate that complexes 1–3 are isomorphous and exhibit three-dimensional metal–organic frameworks with uncommon (4,5)-connected topology, which contain open channels occupied by the lattice water molecules. The photoluminescent properties of complex 2 were also studied.     

可交联型含氟嵌段共聚物的ATRP法制备及其在疏水涂膜中的应用

研究采用ATRP法制备了可交联型含氟嵌段共聚物P(MMA-HEMA-BMA)-b-PFMA,并考察了选择性溶剂的种类和成膜温度对聚合物胶束形态、涂膜表面微观结构形貌、涂膜疏水性和综合性能的影响。研究结果表明:在THF、DMF、F113、TFPE中含氟嵌段共聚物均能形成核壳结构胶束,胶束溶液成膜后涂膜表面具有一定微观粗糙结构。当以TFPE为溶剂,成膜温度为80℃时,含氟官能团能迁移到含氟嵌段共聚物的表面,涂膜表面的静态水接触角最大为135.2°,涂膜附着力为1级,硬度为HB,表现出优良的综合性能。     

Thermodegradation of Poly(4-Vinylpyridine-co-Maleic Acid-co-Divinylbenzene) and N-oxide Derivatives: Modeling of TG and DTG Curves

Copolymer networks based on 4-vinylpyridine (4VPy)/maleic acid (MA)/divinylbenzene (DVB) and their N-oxide derivatives have been investigated by thermogravimetric analysis (TG) to evaluate their thermal stability in nitrogen atmosphere at fixed heating rate. Thermal stability was determined from TG curves to investigate the influence of 4VPy content and introduction of N-oxide groups. The TG and DTG curves of unmodified copolymers clearly show one thermodegradation stage and the same kinetic pathway. The decomposition temperatures do not depend on the 4VPy content. The copolymers modified by oxidation present lower thermostability than unmodified showing that the introduction of N-oxide groups modifies their kinetic pathways. A kinetic model Ozawa was used to determine the kinetic parameters. The apparent thermal decomposition activation energies (Δ E _d) of the unmodified copolymer under nitrogen was higher than that in modified copolymer.     

Preparation of functional poly(acrylates and methacrylates) and block copolymers formation based on polystyrene macroinitiator by ATRP

The polymerization by ATRP of hydroxy and amino functional acrylates and methacrylates with tert-butyldimethylsilyl (TBDMS) or tert-butyloxycarbonyl (BOC) protective groups has been studied for the first time achieving high control over molecular weight and polydispersity. Detailed investigation of the ATRP of 2-{[tert-butyl(dimethyl)silyl]oxy}ethyl acrylate (M2b) in bulk and 2-[(tert-butoxycarbonyl)amino]ethyl 2-methylacrylate (M3a) in diphenyl ether (DPE) showed that the type of ligand plays an important role on either the polymerization rate or the degree of control of the polymerization. Among the ligands used, N,N,N,′N″N″-pentamethyl diethylenetriamine (PMDETA) was the most suitable ligand for ATRP of all functional acrylates and methacrylates. The kinetics of M2b and M3a polymerization using PMDETA as a ligand was reported and proved the living character of the polymerization. Well-defined block copolymers based on a halogen terminated polystyrene (Pst) macroinitiator and the functional acrylate and methacrylate monomers were successfully synthesized by ATRP, and subsequent deprotection of the protective groups from the acrylate or methacrylate segment afforded amphiphilic block copolymers with a specific solubility behavior.     

Synthesis of poly(4‐aminophenol) by horseradish peroxidase and the evaluation of its adsorptivity for silver ions

In this study, poly(4‐aminophenol) was successfully prepared by an enzymatic reaction in water, with its molecular weights ranging from 12,000 to 52,000. The polymerization of 4‐aminophenol produced high yields over a wide pH ranging from 4 to 10. In addition, poly(4‐aminophenol) was also used for silver‐ion adsorption because it was composed of amino and hydroxyl groups. We found that the adsorption capacity of poly(4‐aminophenol) was relevant to the time, pH value, temperature, and concentration of silver ions, and the greatest adsorption capacity of poly(4‐aminophenol) for silver ions was 220 mg/g. Moreover, a series of tests showed that the adsorption of silver ions was mainly achieved by a reduction reaction, and the silver nanoparticles were formed with a face‐centered cubic structure, and their average particle size was about 10 nm. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40367.     

4-(4-氯苯基)环己醇及4-(4-氯苯基)环己酮的合成研究

以氯苯、环己烯、乙酰氯为原料,通过Friedel-Crafts反应、Baeyer-Villiger反应、水解反应得到4-(4-氯苯基)环己醇。通过正交试验得到Friedel-Crafts反应和Baeyer-Villiger反应优化后的工艺条件。4-(4-氯苯基)环己醇总收率达12.9%,较文献收率提高了6%以上。所得醇经次氯酸钠氧化,得到4-(4-氯苯基)环己酮,氧化收率87%,产品的结构经1HNMR、GC-MS鉴定。     

Atom-Transfer Radical Polymerisation (ATRP) as a Tool for the Development of Optical Sensing Phases

The advantages of atom-transfer radical polymerisation (ATRP) for synthesising well-defined polymers have made this technique very popular in recent years for the synthesis of new polymers and copolymers with optical properties. The components involved in ATRP and their effect on composition, functionalities and topology have been reviewed according to the optical properties of the obtained (co)polymers. Because several functionalities and architectures can be combined in ATRP, this technique is a useful tool for the synthesis of new (co)polymers specially designed to meet the requirements of the sensor setup.     

Prediction of trivalent actinide amino(poly)carboxylate complex stability constants using linear free energy relationships with the lanthanide series

There is a gap in the literature regarding the complexation of amino(poly)carboxylate (APC) ligands with trivalent actinides. The chemistry of the trivalent actinides is considered to be nearly identical to that of the trivalent lanthanides, but the trivalent actinides express a slight enhancement when binding APC ligands. Presented in this report is a method of predicting the stability constants of the Pu(III), Am(III), Cm(III), Bk(III) and Cf(III) using linear free energy relationships of the actinides and the lanthanide series for 91 APCs. This method produced actinide stability constants within uncertainties to those in available literature values for most ligands.     

Synthesis and Characterization of Polystyrene-b-Poly(4-vinyl pyridine) Block Copolymers by Atom Transfer Radical Polymerization

We aimed at the synthesis of well-define PS-b-P4VP by using atom transfer radical polymerization in two-step process. First, polystyrenes with benzyl bromide end group (PS-Br; by ATRP) were prepared as macroinitiator for the next ATRP of 4-vinyl pyridine and characterized these polymers from ¹H-NMR and MALDI-TOF. Comparing with MALDI-TOF-MS, ¹H-NMR and GPC analyses, this indicates that the formation of the block copolymer can be observed. During the polymerizations, molecular weight distribution and kinetics have been evaluated from GPC traces and ¹H-NMR analyses. We further characterized the thermal properties of these block polymers by DSC and TGA. DSC measurement on the PS-b-P4VP block copolymers exhibited two glass transitions, indicating that the resulting block copolymers are phase separated. Two maxima differential peaks were observed on the TGA trace for the PS-b-P4VP block copolymers might be assigned to the decomposition of the P4VP blocks at 380 ^○C and the PS blocks at higher temperature.     

Synthesis of rod-coil diblock copolymers by ATRP and their honeycomb morphologies formed by the ‘breath figures’ method

We have synthesized rod-coil diblock PPQ-b-PMMA copolymers by using the versatile atom-transfer radical polymerization method and have characterized them by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The methyl ketone-terminated rod-coil diblock PMMA copolymer has a higher value of T_g, because of its syndiotactic-like structure, and a higher decomposition temperature than does the PMMA homopolymer. The presence of the PPQ block tends to retard the early decomposition of the PMMA chain. A regularly porous, honeycomb-structured film was prepared from the dichloromethane solution of the diblock copolymers under a flow of moist air. The diameters of the spherical pores can be controlled in the range from 0.8 to 3 μm by modifying both the rod-coil copolymers' relative molecular weights and the casting conditions. The wall thickness of the film is varied linearly with the relative molecular mass (M_r).     

Silica nanoparticles functionalized via click chemistry and ATRP for enrichment of Pb(II) ion

ABSTRACT: Silica nanoparticles have been functionalized by click chemistry and atom transfer radical polymerization (ATRP) simultaneously. First, the silanized silica nanoparticles were modified with bromine end group, and then the azide group was grafted onto the surface via covalent coupling. 3-Bromopropyl propiolate was synthesized, and then the synthesized materials were used to react with azide-modified silica nanoparticles via copper-mediated click chemistry and bromine surface-initiated ATRP. Transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis were performed to characterize the functionalized silica nanoparticles. We investigated the enrichment efficiency of bare silica and poly(ethylene glycol) methacrylate (PEGMA)-functionalized silica nanoparticles in Pb(II) aqueous solution. The results demonstrated that PEGMA-functionalized silica nanoparticles can enrich Pb(II) more quickly than pristine silica nanoparticles within 1 h.     

Removal of chromium (VI) from aqueous solutions using poly(4‐vinyl pyridine) beads

Sorption of hexavalent chromium ions from aqueous solution by poly 4‐vinyl pyridine [Poly(4‐VP)] was studied. The batch method was applied for adsorption processes. The effects of initial ion concentration, time, pH and temperature on adsorption were investigated. A treatment time of 60 min was found to be sufficient to reach equilibrium. pH 3.0 was found as the optimum pH value for the process. The maximum adsorption performance was achieved at 86.7 mg g^?1 using 500 mg L^?1 Cr (VI) solutions. The process of adsorption of Cr (VI) was explained by Langmuir isotherm. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2865–2870, 2006