A novel route to poly(2-hydroxyethyl methacrylate) and its amphiphilic block copolymers

The vinyl of the ester group of 2-vinyloxyethyl methacrylate was first selectively reacted with acetic acid to obtain 2-[1-(acetoxy)ethoxy]ethyl methacrylate ( 2 ). This protected monomer was subjected to anionic polymerization in tetrahydrofuran at −60°C in the presence of LiCl, using 1,1-diphenylhexyllithium as initiator. The molecular weight of the polymer could thus be controlled and a narrow molecular weight distribution obtained. The protecting group, 1-(acetoxy)ethyl, could be easily eliminated (by quenching the polymerization reaction with methanol and water) to generate poly(2-hydroxyethyl methacrylate) (poly(HEMA)). Block copolymers were also prepared by the sequential anionic polymerization of MMA and 2 or styrene and 2 . They possess narrow molecular weight distributions, and controlled molecular weights and compositions. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1865–1872, 1998     

Synthesis of carbosilane block copolymers by means of a living anionic polymerization of 1,1-diethylsilacyclobutane

Block polymerization of 1,1-diethylsilacyclobutane with styrene derivatives and methacrylate derivatives was investigated. Sequential addition of styrene to a living poly(1,1-diethylsilabutane), which was prepared from phenyllithium and 1,1-diethylsilacyclobutane in THF–hexane at −48°C, gave poly(1,1-diethylsilabutane)-b-polystyrene. Similarly, addition of 4-(tert-butyldimethylsiloxy)styrene to the living poly(1,1-diethylsilabutane) provided poly(1,1-diethylsilabutane)-b-poly(4-(tert-butyldimethylsiloxy)styrene). Poly(1,1-diethylsilabutane)-b-poly(methyl methacrylate) was obtained by treatment of living poly(1,1-diethylsilabutane) with 1,1-diphenylethylene followed by an addition of methyl methacrylate. Poly(1,1-diethylsilabutane)-b-poly(2-(tert-butyldimethylsiloxy)ethyl methacrylate) was also synthesized by adding 2-(tert-butyldimethylsiloxy)ethyl methacrylate to the living poly(1,1-diethylsilabutane) which was end-capped with 1,1-diphenylethylene in the presence of lithium chloride. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2699–2706, 1998     

Ambient Electrosynthesis of Ammonia: Electrode Porosity and Composition Engineering

Ammonia, a key precursor for fertilizer production, convenient hydrogen carrier, and emerging clean fuel, plays a pivotal role in sustaining life on Earth. Currently, the main route for NH₃ synthesis is by the heterogeneous catalytic Haber–Bosch process (N₂+3 H₂→2 NH₃), which proceeds under extreme conditions of temperature and pressure with a very large carbon footprint. Herein we report that a pristine nitrogen‐doped nanoporous graphitic carbon membrane (NCM) can electrochemically convert N₂ into NH₃ in an acidic aqueous solution under ambient conditions. The Faradaic efficiency and rate of production of NH₃ on the NCM electrode reach 5.2 % and 0.08 g m^?2 h^?1, respectively. Functionalization of the NCM with Au nanoparticles dramatically enhances these performance metrics to 22 % and 0.36 g m^?2 h^?1, respectively. As this system offers the potential to be scaled to industrial levels it is highly likely that it might displace the century‐old Haber–Bosch process.     

Materials with Nanoscale Porosity: Energy and Environmental Applications

In this personal account, several key inventions on designing novel microporous and mesoporous materials, and their applications in energy and environmental research are reviewed. Although, crystalline materials with sub‐nanometer pore size regime like zeolites, AlPOs, MOFs, ZIFs etc. are known over the years, silicious and non‐silicious mesoporous materials have revolutionized the research on the materials with nanoscale porosity in last two and half decades. A wide range of inorganic, organic‐inorganic hybrid as well as purely organic mesoporous materials with either periodic or disordered mesopores are known. Apart from conventional hydrothermal syntheses involving soft templating route, hard templating, evaporation induced self‐assembly (EISA), electrochemical or solvothermal (using hydrophilic solvents) synthetic routes are often employed in designing a large spectrum of mesoporous materials. Ease of synthesis using available cheap raw chemicals and versatility in the framework compositions together with the unique surface properties like exceptionally high surface area, pore volume and tunability in pore dimensions have made these materials very exciting to a wide range of researchers working on materials chemistry. Nanoscale porosity in the semiconductor nanomaterials is highly beneficial for the photocatalytic, optoelectronic and related light‐harvesting applications. Their high chemical stability has been explored intensively in designing novel heterogeneous catalysts for the synthesis of biofuels from biomass or CO₂ fixation to reactive organic molecules for the synthesis of fine chemicals and fuels, which has a large impact on energy and environmental research for the years to come. Diversity in mesoporous frameworks and their potential applications related to light harvesting, generation of renewable energy and synthesis of value added fine chemicals and fuels through environment friendly routes are mostly focused in this review.     

Synthesis and Characterization of Novel Organic／Inorganic Hybrid Polymers Containing Polyhedral Oligosilsesquioxanes

Hybrid polymers, poly(vinyl pyrrolidone-co-isobutyl styryl polyhedral oligomeric silsesquioxanes)s (PVP-POSS) were synthesized by one step polymerization and characterized using GPC and DSC. Addition of POSS significantly increases the Tg of polyvinylpyrrolidone at a fair high POSS content and obtained high molecular weight polymers with very narrow molecular distribution. The POSS content in the resulted hybrids can be controlled by varying the POSS feed ratio.     

Synthesis and Characterization of Polymeric Materials from Vegetable Oils

Although the petrochemical polymers have revolutionized the technological development, the intensive use of these materials have contributed to the global pollution. In this context, researches involving ecofriendliness materials are growing up, as well as, a current interest in developing materials from inexpensive and renewable resources, such as vegetable oils. In this work, is described the synthesis of polymeric materials by thermal polymerization from linseed oil (Linum usitatissimum L.) and passion fruit oil (Passiflora edulis) and their characterization by gas chromatographic (GC), Fourier transform infrared (FTIR) spectroscopy, solubility in organic solvents, thermogravimetry (TG), differential scanning calorimetry (DSC) and Raman spectroscopy. The TG curve shows that those polymeric materials present two stages of decomposition. DSC plots of the vegetable oils showed some endothermic and exothermic transitions which are not present in the DSC curves corresponding to oil-based polymers. The Raman spectra of the polymers indicate declining of absorbance in the region of CC stretching (∼1600 cm⁻¹). This absorption was used to estimate the degree of polymerization (79% and 67.5% for linseed and passion fruit oils, respectively).     

分子识别与温度响应复合智能材料

研究和开发具有双重和多重刺激响应型智能高分子材料已成为一个重要的发展方向。本文详细地综述了我们近年来在基于聚(N-异丙基丙烯酰胺)(PNIPAM)和β-环糊精(β-CD)的复合智能线型高分子、复合智能微球和复合智能膜方面的研究进展。不同形式的复合智能材料均采用相同的反应机理制备。综述了制备工艺条件、共聚单体比例、接枝率、客体分子种类和浓度等因素对于不同形式复合智能材料的温度响应性和分子识别特性的影响规律,并对复合智能膜在亲合分离、控制释放和手性拆分等方面的应用进行了介绍。评述了分子识别与温度响应复合智能材料的研究意义和发展方向,并对其应用前景进行了展望。     

Covalent immobilization of invertase on chemically activated poly(2-hydroxyethyl methacrylate) microbeads

Properties of invertase immobilized on poly(2-hydroxyethyl methacrylate) microbeads activated by epichlorohydrin or cyanuric chloride were studied. After 20 repeated uses for 3 days, the activity of the immobilized enzyme was 92–93%. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1793–1797, October, 2006.     

Synthesis and Characterization of Polymeric Acid‐Doped Polyaniline Interpenetrating Polymer Networks

Polyaniline (PANI)/poly(2‐acrylamido‐2‐methylpropane sulfonic acid) (PAMPS) semi‐interpenetrating network polymers (semi‐IPNs) were prepared using the simultaneous method. The formation and properties of the interpenetrating PANI/PAMPS semi‐IPNs were investigated using Fourier transform infrared spectroscopy, X‐ray diffraction, solid‐state ¹³C‐NMR, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The interaction of PAMPS with PANI as a polymeric acid dopant was also investigated. These semi‐IPNs had a different microstructure compared to that of pure PANI. Packing structures and several decomposition steps were ordered for each semi‐IPN, while pure PANI exhibits a single amorphous peak and one decomposition step. The NMR spectra show that these peaks broaden and shifted downfield in the semi‐IPNs. A thermal reaction between PANI and PAMPS was observed using DSC and TGA, and the data from the two techniques are in agreement.     

Synthesis and miscibility studies of [60]fullerenated poly(2‐hydroxyethyl methacrylate)

[60]Fullerenated poly(2‐hydroxyethyl methacrylate)s containing 0.6–3.0 wt % C₆₀ were synthesized. These polymers are soluble in methanol and N,N‐dimethylformamide (DMF). [60]Fullerenated poly(2‐hydroxyethyl methacrylate)s with higher C₆₀ contents are only sparingly soluble in DMF and virtually insoluble in other organic solvents. A loading of 1.2 wt % C₆₀ in poly(2‐hydroxyethyl methacrylate) does not greatly affect its miscibility with poly(N‐vinyl‐2‐pyrrolidone), poly(1‐vinylimidazole), and poly(4‐vinylpyridine). © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1157–1166, 2002     

Synthesis and Characterization of Novel Amorphous Hybrid Silica Materials

Novel amorphous organic-inorganic hybrid silica materials have been prepared by the conventional sol-gel reaction of bis(gamma-trimethoxysilyl)propylamine (TMSPA) and tetraethyl orthosilicate (TEOS) in the presence of cetyltrimethylammonium bromide (CTABr) as a structure directing agent. The gelation of the hybrid silica gels took place faster as the TMSPA composition was higher. Infrared Spectroscopy (IR), Thermogravimetric Analysis (TGA), X-Ray Diffraction (XRD), and Scanning electron microscope (SEM) were used to characterize various hybrid materials. Nitrogen adsorption desorption isotherms at 77 K were used to determine the surface area, and average pore size. The hybrids were composed of macropores and a small amount of micropores. According to SEM photographs, the hybrids were composed of quite uniform aggregate of spherical particles with ca. 60 nm in diameter.     

PLGA-(PEG-ASP)n共聚物的合成与性能研究

以辛酸亚锡[Sn(Oct)2]为催化剂,聚乙二醇／L-天冬氨酸预聚物[(PEG-ASP)n]为共引发剂,引发D,L—LA和GA开环共聚合成具有功能侧氨基的PLGA-(PEGASP)n共聚物。通过FTIR、^1H—NMR、DSC、表面接触角测定和细胞培养等方法研究共聚物的结构与性能。结果表明,共聚物为典型的非晶态聚合物;共聚物的亲水性以及对骨髓基质细胞的粘附能力和粘附效率均明显优于PLGA。     

Characterization of azo-containing polydimethylsiloxanes and their copolymers with methyl methacrylate

Azo group-containing polydimethylsiloxanes (PDMS–ACP), macroazoinitiators, were prepared by polycondensation reaction of 4,4′-azobis-4-cyanopentanoyl chloride (ACPC) with hydroxybutyl-terminated polydimethylsiloxane (PDMS) of varying molecular weights. The activation energy (E_a), activation enthalpy (ΔH^‡), and activation entropy (ΔS^‡) of the thermodecomposition of PDMS-ACP in toluene increased with increase in poly-dimethyl-siloxane chain length (SCL) in PDMS moieties, while the activation free energy (ΔG^‡) was independent on the SCL. The polydimethylsiloxane-poly(methyl methacrylate) block copolymers (PDMS-b-PMMA) were prepared by the use of PDMS-ACP macroazoinitiators, and they were characterized by ¹H-, ²⁹Si-, and ¹³C-nuclear magnetic resonance (NMR) spectroscopies. The microstructure and morphology of copolymers were investigated by proton spin–spin relaxation measurements and scanning electron microscopy (SEM). © 1996 John Wiley & Sons, Inc.     

Effect of reaction parameters on the particle size in the dispersion polymerization of 2-hydroxyethyl methacrylate

Poly(2-hydroxyethyl methacrylate) particles in the micron size range were obtained by the dispersion polymerization. Cellulose acetate butyrate and dibenzoyl peroxide were used as steric stabilizer and initiator, respectively. The ultimate particle size could be adjusted by the selection of a suitable polymerization medium consisting of an alcohol added to toluene and by varying their relative amounts. The particle size increased with increasing solubility parameter of the mixture, i.e., by decreasing the toluene/2-methylpropan-1-ol, toluene/butan-2-ol, and toluene/3-methylbutan-1-ol ratio. The particle size decreased with increasing concentration of the stabilizer and/or initiator. At the same time, the particle size distribution became narrower. Particles prepared from polymerization mixtures purged with nitrogen before the start of polymerization were smaller, and of narrower distribution, than those prepared from nitrogen-non-purged mixtures. Equilibrium swelling of particles in toluene decreased with the decreasing content of toluene in the polymerization mixture. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3785–3792, 1999     

PMMA-ZrO2等有机无机杂化材料的制备与表征

以烯丙基乙酰丙酮作为偶闻剂应秀溶胶凝胶法制备了一系列均匀透明的ＰＭＭＡ－ＺｒＯ２等有机无机杂化材料，利用ＵＶ，ＩＲ对其制备过程进行了研究，并测定了所得杂化玻璃的ＴＧＡ性质。     

Water sorption properties of poly(ethyl acrylate-co-hydroxyethyl methacrylate) macroporous hydrogels

Synthetic porous hydrogels are becoming more and more important in the field of biomaterials. Different studies demonstrate that the porous structure promotes the colonisation of living cells and improves the biocompatibility of the implants. The macroporous structure allows not only the control of cellular ingrowth morphology but also the mechanical integration and the regulation of nutrient and hydraulic flow in the hydrogel. In this work poly(ethyl acrylate-co-hydroxyethyl methacrylate) (PEA/PHEMA) copolymers were polymerized using 2% of ethylene glycol dimethacrylate as cross-linking agent and azoiso-botyronitrile as initiator. Five samples were prepared with the EA/HEMA weight ratios of 75/25, 50/50, 25/75 and pure PEA and PHEMA polymers, obtaining different degrees of hydrophilicity. The macroporous structure was obtained by adding poly(acrylonitrile) fibres to the monomers. After polymerization the fibres were eliminated by dissolution in dimethyl formamide. The holes are cylinders of approximately 40μm diameter and are all, more or less, in the same direction, although they are not uniformly distributed. Water sorption isotherms and diffusion properties of the macroporous samples are compared with the samples without holes.     

苯乙烯-甲基丙烯酸甲酯嵌段共聚物的合成与表征

采用阴离子聚合技术合成了一系列苯乙烯-甲基丙烯酸甲酯的两嵌段共聚物(PS－b－PMMA)．采用GPC、FTIR、NMR(¹HNMR、¹³CNMR和固体NMR)和DMA等手段进行了表征．结果表明,所得产物为高分子量、窄分布、具有微相分离结构的两嵌段共聚物．     

基于间苯三酚及其衍生物构筑新型有机多孔材料

有机多孔材料凭借其高比表面积、孔道可调性、易功能化修饰和结构多样性等特征,在催化、能源、吸附与分离等多个领域中展现了巨大应用潜力.对多官能度有机化合物单体以及高效聚合反应的巧妙应用,为新型有机多孔材料的创制提供了强有力的工具,成为该领域的研究热点.以C₃对称型的间苯三酚及其衍生物为例,综述了其在一系列新型有机多孔材料高效构筑中的最新研究进展.