Photopolymerization of enzymatically synthesized methacrylated poly(caprolactone) with poly(ethylene glycol) macromonomer

Polycaprolactone (PCL) based α,ω-methacrylated macromonomer (DMPCL) was synthesized via enzymatic ring-opening polymerization (eROP) by using Novozyme 435 as the enzyme immobilized catalyst. DMPCL was further photopolymerized with monofunctional poly(ethylene glycol) methyl ether methacrylate (PEGMA-950) macromonomer and trimethylolpropane triacrylate (TMPTA) as tri-functionalized crosslinking agent in glass vials when CHCl₃ was the solvent and Irgacure 819 was the photoinitiator. Ultraviolet (UV) Light Emitting Diode (LED) bulbs enabled photoinduced reactions at room temperature with low heat generation and high reaction efficiency. The obtained gels were characterized with Fourier Transform Infrared Spectroscopy (FT-IR) and Differential Scanning Calorimetry (DSC). DMPCL participated as an effective crosslinking agent in the photopolymerization of PEGMA-950. Combined usage of DMPCL and PEGMA-950 resulted in significantly more effective polymerization than the separate photopolymerizations of these macromonomers.     

Use of Kirkwood–Buff Integrals for Extracting Distinct Diffusion Coefficients in Macromolecule–Solvent Mixtures

The possibility to extract velocity correlation quantities from fluctuation thermodynamic properties is explored in the case of macromolecule–solvent mixtures. Indeed, Kirkwood–Buff integrals, G_ij, together with self‐diffusion and viscosity data can provide an approximation for distinct diffusion coefficients (DDCs), D^d_ij. Herein, D^d_ij for binary polyethyleneglycol (PEG)(i)–water(0) systems is calculated. These systems show positive values of D^d_ii coefficients, indicating strong PEG–PEG interaction, and providing marker of water mediated PEG–PEG networks. The efficiency of several standard DDCs present in literature for D^d_ij analysis is compared, summarizing the usefulness of each one, depending on the nonideality degree.

     

Photocatalytic activity of TiO2/SnO2/Pt prepared by the sol-gel method

This investigation compares the photodegradation performance of C.I. Reactive Red 2 (RR2) in single- and coupled-photocatalyst systems. The photocatalysts were produced via the sol-gel method. PEG and Pt addition increases the decolorization rate (1.6–2.12 h⁻¹), the amount of sulfate released and the DOC reduction percentage in coupled photocatalyst systems the cause of PEG improving the homogeneity of the final product and incorporating Pt into the lattice reduced the band gap of photocatalysts.     

Liquid membranes for gas/vapor separations

A review on developments of liquid membranes (LMs) in the field of gas and vapor separation of the last 16 years is presented. Liquid membrane configurations employing supports, i.e. immobilized, supported and contained liquid membranes are focussed and detailed information on the respective materials, i.e. supports (supplier, type, thickness, pore width, porosity, tortuosity), liquids and carriers, are presented together with their specific separation tasks. Performance of different LMs in terms of permeability and selectivity as well as stability (duration of testing, applied differential pressures) are compared and discussed. Finally, different preparation methods of LMs are illustrated.     

Preparation of stimuli-responsive nanogels based on poly(N,N-diethylaminoethyl methacrylate) by a simple “surfactant-free” methodology

The synthesis of poly(N,N-diethylaminoethyl methacrylate)-core-polyethyleneglycol-shell (PDEAEM-core-PEG-shell) nanogels was achieved by using a “surfactant-free” emulsion polymerization with the aid of commercially available polyethyleneglycol methyl ether methacrylates (PEGMAs) as polymerizable stabilizers. By adjusting the synthetic parameters like the choice of initiator, cross-linker, PEGMA:DEAEM ratio, and molecular weight of PEGMA, a series of core-shell nanogels varying in size (50–350 nm), PDEAEM content, and pH/temperature responsive behavior were obtained in reactions taking only 60 min. The nanogels were used as nanoreactors for the preparation of gold nanoparticles. The PEGylated nanogels have a great potential to be used for diagnosis and therapy.     

聚乙二醇-硫酸铵-亚硝基R盐体系中钴(Ⅱ)的分离及其存在形态

在 ｐＨ ４．０～６．０的 ＨＡｃ－ＮａＡｃ缓冲溶液中，Ｃｏ（Ⅱ）、Ｆｅ（Ⅲ）、Ｎｉ（Ⅱ）、Ｃｕ（Ⅱ）等金属离子与亚硝基Ｒ盐可形成稳定络合物。加入ＨＣＩ适当提高溶液酸度（ＨＣＩ浓度在０．３～０．６ｍｏｌ／Ｌ），用聚乙二醇２０００（ＰＥＧ）－硫酸铵－亚硝基Ｒ盐体系萃取，Ｃｏ（Ⅱ）可被ＰＥＧ相几乎完全萃取，而Ｆｅ（Ⅲ）、Ｎｉ（Ⅱ）、Ｃｕ（Ⅱ）基本上不被萃取。实现了Ｃｏ（Ⅱ）、Ｆｅ（Ⅲ）、Ｎｉ（Ⅱ）、Ｃｕ（Ⅱ）混合离子合成样品和硅酸盐岩矿实际样品中Ｃｏ（Ⅱ）的分离与测定。同时吸收光谱、摩尔比、连续浓度变换、加入表面活性剂等实验表明，在萃取相Ｃｏ（Ⅱ）与亚硝基Ｒ盐是１：３络阴离子形式存在的。     

聚苯醚磺酸锂与聚乙二醇共混体系的离子导电性

本文研究影响聚乙二醇（ＰＥＧ）增塑聚苯醚磺酸锂（ＳＰＰＯＬｉ）电导率的各种因素，如摩尔比，及ＰＥＧ分子量等。ＳＰＰＯＬｉ／ＰＥＧ具单离子导体的特征，试样最高室温电导可达１０＾－５Ｓ／ｃｍ。     

Biofunctionalization of polyelectrolyte microcapsules with biotinylated polyethylene glycol-grafted liposomes

Hollow polyelectrolyte microcapsules (PEMC) are prepared using layer-by-layer self-assembly of polyelectrolytes on melamine formaldehyde templates, followed by template dissolution, and subsequent coating with biotinylated polyethylene glycol-grafted liposomes. These potential site-specific carrier systems show a high specificity for NeutrAvidin binding and a strong resistance against unspecific protein binding. It is concluded that this design with NeutrAvidin as the outermost layer of such capsules provides an ideal platform for the biofunctionalization of PEMC as drug delivery systems or as artificial cell-like structures for biomimetic studies.     

新型梳状高分子固体电解质的研究：Ⅰ.聚合物主体物的合成与表征

聚乙二醇单甲醚和甲醇依次与马来酸酐／乙烯基甲醚交替共聚物在溶液中两度酯化，合成了侧链长度不同的３种梳形高分子。用丁酮作为酯化反应介质可使反应完全。产物为白色橡胶状固体，成膜性较好。借助ＩＲ、１３ＣＮＭＲ和元素分析手段对产物的结构进行了确认。     

Sol-Gel Carrier Systems for Controlled Drug Delivery

Embedding of the well-known coronary therapeuticum nifedipine into a modified silica matrix by the sol-gel technique allows its releasing behavior to be controlled to a high degree. The liberation rate is proportional to temperature and is increased by the addition of penetration agents such as sorbitol, but is inversely proportional to particle size and is decreased by modification of the silica matrix with methyl-triethoxysilane or polyethylene-glycol. It is presumed that the drug is dispersed in the gel matrix and that diffusion occurs through solvent-filled capillary channels. The liberation rate is governed by the relationship between the rates of dissolution and diffusion.