Surface Lewis acid-base properties of polymers measured by inverse gas chromatography

Surface Lewis acid-base properties are significant for polymers materials. The acid constant, K(a) and base constant, K(b) of many polymers were characterized by some researchers with inverse gas chromatography (IGC) in recent years. In this paper, the surface acid-base constants, K(a) and K(b) of 20 kinds of polymers measured by IGC in recent years are summarized and discussed, including seven polymers characterized in this work. After plotting K(b) versus K(a), it is found that the polymers can be encircled by a triangle. They scatter in two regions of the triangle. Four polymers exist in region I. K(b)/K(a) of the polymers in region I are 1.4-2.1. The other polymers exist in region II. Most of the polymers are relative basic materials.     

Polybenzimidazoles containing anthracene photodimer

Polybenzimidazoles that contained anthracene photodimer were prepared. The molecular weights of the polymers prepared by the photopolymerization of bis-anthrylbenzimidazoles were limited by the precipitation of the resulting polymers from the reaction organic solvents. Higher molecular weight polymers were obtained by the photopolymerization of bis-anthryl-Schiff's bases, followed by the oxidation of the resulting polymers. These polymers were soluble in acidic solvents such as formic and sulfuric acids but were insoluble in organic solvents.     

刚性链侧链型液晶高分子合成与研究

以自由基聚合方法，合成了一系列含有３个苯环通过酯键相联的液晶性单体及其聚合物，这类刚性液晶基元不通过柔性间隔基而直接竖挂在聚丙烯酸酯大分子主链上，具有很高的Ｔｇ·ＤＳＣ及偏光显微镜结果表明，所有的单体和聚合物均为向列型热致性液晶。     

新的含T－型二维液晶基元的液晶高分子的合成

采用低温溶液聚合方法，以Ｎ－（２，５－二羟基苯）亚甲基－４－取代苯胺和不同结构的二酰氯为单体，合成了两类新的高分子．聚合物的液晶行为用ＤＳＣ、偏光显微镜和Ｘ射线衍射进行了表征，发现其中一类为向列型热致液晶高分子，另一类则无液晶性．随单体结构的改变，聚合物的特性粘数、熔点（Ｔｍ）和液晶态的清亮点（Ｔｉ）均呈现规律性变化。     

新的含T-型二维液晶基元的液晶高分子的合成

采用低温溶液聚合方法,以N-(2,5-二羟基苯)亚甲基-4-取代苯胺和不同结构的二酰氯为单体,合成了两类新的高分子。聚合物的液晶行为用DSC、偏光显微镜和X射线衍射进行了表征,发现其中一类为向列型热致液晶高分子,另一类则无液晶性。随单体结构的改变,聚合物的特性粘数、熔点(Tm)和液晶态的清亮点(Ti)均呈现规律性变化。     

Linear polymers of acrylic monomers containing an acetylenic moiety

1-Acryloxy-2-butyne and 1-methacryloxy-2-butyne were synthesized and polymerized by means of anionic initiators to soluble linear polymers containing acetylenic bonds in the pendant side chains. In contrast, insoluble, crosslinked polymers were formed when cationic and radical initiators were used. The unpolymerized acetylenic bonds in the resulting linear polymers were shown to be present by infrared spectroscopic methods and by the following post-reactions of these bonds: (1) the thermal- and radical-initiated crosslinking of the linear polymers through the acetylenic bonds; (2) the post-bromination of the acetylenic bonds; and (3) the reaction of decaborane with the acetylenic bonds. The anionic copolymerization of both monomers with a number of selected monomers was performed and the copolymer reactivity ratios for several of the comonomer pairs were determined. Dibromination of the linear polymers affords self-extinguishing polymers with apparently good hydrolytic stability. Decarbonation of the linear polymers yields soluble polymers which do not soften up to 300°C. The linear polymers and copolymers, as well as their partially brominated and partially decaboronated products, may be classified as “self-reactive” polymers which yield thermosetting polymers.     

Thermoanalytical studies on specialty polymers in Japan

Thermoanalytical studies on specialty polymers in Japan are reviewed. The basic and applied researches for the developments of new specialty polymers such as high-performance polymers, liquid crystalline polymers, and biodegradable polymers during the 1990's are introduced from the standpoint of thermal analysis. Many studies were performed for the improvements of durability and thermal stability of engineering polymers, biodegradable polymers and so on. A special topic of researches on the thermal behavior of polymers by high-pressure differential thermal analysis is included in this review. This revised version was published online in July 2006 with corrections to the Cover Date.     

Methods for the synthesis of uniform polymers

The difficulties encountered in the preparation of polymers that are uniform chemically, structurally, and in their molecular weight are due mainly to the wide variety of possible polymers. This arcticle gives a review of attempts to synthesize homogeneous polymers by chain reactions and by stepwise synthesis. Syntheses on templates are extremely important in living cells; methods have recently been found for syntheses of this type that are independent of natural processes. Uniform polymers can also be obtained by reactions on existing polymers. In replicating polymers, this in principle requires the modification of only one polymer molecule.     

Adhesion of filamentous microbial cells on paper covered with ionic polymers by radiation polymerization

The adhesion of filamentous microbial cells such as Trichoderma reesei was studied by using carriers covered with polymers which were prepared by the radiation polymerization of ionic monomers. The weight of the cells adhering to the carriers increased with increasing cationic monomer content, indicating that the surface of the polymers prepared from cationic and hydrophobic monomers is suitable for the adhesion of the cells. The production of cellulase in the cells adhered to polymers from cationic monomers was higher than that in cells adhered to polymers prepared from anionic monomers. The growth of the cells adhered to the surfaces of the polymers was affected by the hydrophilicity of the polymers.     

Soluble blue light emitting pyridine-containing polymers prepared by oxidative-coupling copolymerization

Novel polymers containing pyridine moieties in main chains have been prepared by facile oxidative-coupling co-polymerization of pyridine N-oxide with N-alkyl carbazole and fluorene as the precursor polymers, which were reduced to the pyridine-containing polymers respectively. The polymers were characterized by FT-IR, ¹H NMR, UV-Vis, X-ray, thermo-gravimetric analysis, and fluorescence spectroscopy. The pyridine-containing polymers good solubility in convenient organic solvents, high thermal stability with the onset decomposition temperature above 310 °C. The electrochemical behaviors of the polymers were investigated by cyclic voltammetry; the HOMO and LUMO energy level of the polymers were estimated from the electrochemistry and UV-Vis spectroscopy. The fluorescence spectra of the pyridine-containing polymers display blue light emitting properties in both solution and solid-state film.     

用后功能化方法合成含吲哚二阶非线性光学发色团侧基的高分子

用后功能化方法合成了两类连有吲哚二阶非线性光学发色团侧基的高分子.通过核磁、红外、紫外-可见、示差扫描量热分析、分子量测定等手段对所得高分子进行了鉴定.此合成方法简便易行,易于产物的分离提纯,为二阶非线性光学材料的合成提供了一种新方法.     

Styrene-PEG (600) DMA Crosslinked Polymers for Absorption of Oil Derivatives

In this work, styrene (St) based crosslinked polymers were prepared for removal of oil derivatives from aqueous solutions. Polyethylene glycol (600) dimethacrylate (PEG (600) DMA) was used as crosslinker in synthesis of styrene based crosslinked polymers, for the first time. The polymers were characterized by FTIR, SEM, elemental analysis and solvent (toluene, chloroform and fuel-oil) absorption capacities. The effects of different reaction parameters like crosslinker type, diluents amount and the presence of pore forming agent on the absorption properties of polymers were investigated. The polymers synthesized by using PEG (600) DMA have higher solvent absorption capacity than that of synthesized by using conventional crosslinker. Furthermore, the polymers synthesized in the presence of good diluents have higher absorption capacities. The addition of pore forming agent into the reaction medium has also improved the absorption rate of polymers. The absorption capacity of polymers in different solvents is in order of chloroform > toluene > fuel-oil. It was seen that oil derivatives can be removed efficiently from water by the St-PEG (600) DMA polymers.     

Studies on the thermotropic liquid crystalline polymer. XII. Synthesis and properties of crosslinkable thermotropic liquid crystalline homo- and copoly(ether-ester)s

A series of crosslinkable thermotropic liquid crystalline poly(ether-ester)s and copoly(ether-ester)s was prepared. All of the polymers were crosslinked by thermal treatment or photo-irradiation upon heating. The thermal stability and thermal crosslinking reaction of these polymers were investigated. These polymers also could be crosslinked by copolymerization with vinyl monomers, such as styrene or methyl methacrylate. The crosslinked polymers exhibited thermotropic liquid crystalline behavior after softening by heating. The phase behavior of linear polymers and crosslinked polymers was studied by differential scanning calorimetry (DSC) and an optical polarizing microscope equipped with a heating stage. © 1995 John Wiley & Sons, Inc.     

含酰亚胺环酞菁聚合物性能的研究

双邻苯二甲腈单体在催化剂作用下通过熔融聚合得到酞菁聚合物。以IR、DTA、TG等对单体和酞菁聚合物的结构和热性能进行了表征和研究。此外,还进行了单体和聚合物的溶解性试验。结果表明,含酰亚胺环的酞菁聚合物具有优良的热和热氧稳定性,化学惰性和高的成碳率(64.6～65.6％,N_2,>800℃)。这类聚合物可望作为高性能材料应用于宇航等部门。     

New Polymer Structures

A number of new polymers have been studied. They include polymers obtained by chain reaction polymerization of olefins and epoxides with functional groups where the polymerizable group was separated from the functional group by an inert spacer group, the preparation of head-to-head polymers, and the preparation of optically active polymers based on the macromolecular asymmetry.     

Solvent‐Annealing‐Induced Nanowetting in Templates: Towards Tailored Polymer Nanostructures

We study the solvent‐annealing‐induced nanowetting in templates using porous anodic aluminum oxide membranes. The morphology of polystyrene and poly(methyl methacrylate) nanostructures can be controlled, depending on whether the swollen polymers are in the partial or complete wetting regimes, which are characterized by the spreading coefficient. When the swollen polymers are in the partial wetting regime, polymers wet the nanopores by capillary action, resulting in the formation of polymer nanorods. When the swollen polymers are in the complete wetting regime, polymers form wetting layers in the nanopores, resulting in the formation of polymer nanotubes. The solubility parameters of polymers and solvents are also used to predict the wetting behavior of swollen polymers in cylindrical geometry.     

Thermal studies and chromium removal efficiency of thermoresponsive hyperbranched copolymers based on PEG-methacrylates

This study deals with the removal of chromium species from aqueous dilute solutions using thermoresponsive linear and hyperbranched copolymers based on PEG-methacrylates. The thermal stability of polymers was studied by thermogravimetric analysis and chemiluminescence emission, which evidenced a slightly enhanced stability for hyperbranched polymers respect to linear structures. Their LCST was successfully determined by TOPEM (temperature-modulated DSC), and similar values to those obtained by UV spectroscopy were obtained. The adsorption capacities for chromium hexavalent of the polymers have been investigated as function of LCST. The results showed highest retention capacity of Cr(VI) for all polymers above LCST. Hyperbranched polymers were more efficient than linear polymers, because of the structure of the polymers. Hyperbranched polymers when precipitate form a network with more nanocavities where the chromium can be adsorbed. The efficiency increased with ratio of OEGMA/DEGMA, reaching a maximum retention capacity value of 40 mg Cr(VI)/g polymer.     

SYNTHESIS AND CHARACTERIZATI0N OF POLYMETHACRYLATES BEARING HETEROCYCLIC AZO GROUP AND MESOGENIC GROUP FOR NONLINEAR OPTICS

The methacrylate monomers bearing mesogenic group and heterocyclicazo dye have been synthesized. The monomeric dye was copolymerized with the mesogenicmonomer using a free radical initiator to produce polymers useful for nonlinear optics. Themonomers and polymers were characterized by IR, ~1H-NMR, and UV-Vis spectra. Theaverage molecular weight (M_w and M_n) of the polymers were determined by gel permeationchromatography. The thermal properties of the polymers such as thermal stability andphase transition behavior were studied by thermogravimetric analysis, differential thermalanalysis, polarizing optical microscope and X-ray diffractometer. The results demonstratethat the synthesized polymers are crystalline polymers at room temperature and no liquidcrystalline phases were observed for all of them.     

Molecular imprinting polymerization by Fenton reaction

The aim of this study is the preparation of molecularly imprinted polymers by employing a redox pair as initiator system. Bulk molecularly imprinted polymers were synthesized by using Fenton reagents as initiator system. Theophylline, methacrylic acid, and ethylene glycol dimethacrylate were employed as model template, functional monomer, and crosslinking agent, respectively. Conventional imprinted polymers were also prepared by using 2,2′-azoisobutyronitrile in order to evaluate the efficiency of the proposed initiator system. Redox molecularly imprinted polymers and conventional molecularly imprinted polymers were characterized by water uptake measurement, while the imprinting effect of synthesized polymers were evaluated by performing binding experiments in organic (acetonitrile) and in water (buffered water solution at pH = 7.4) media.     

温度敏感树形聚合物

温度敏感树形聚合物结合了温敏聚合物对温度具有响应行为的特点以及树形聚合物非线形构造的方式、大尺度、结构易于调节和功能化等特征,在智能材料和生物医药等领域有着重要的研究价值和应用前景。此类聚合物可以通过在树形聚合物表面引入温敏基元、控制聚合物结构的亲疏水比例以及采用温敏基元直接构筑聚合物等方式形成,其温敏性可以通过调控聚合物内部或外部基团的亲疏水性、树枝化基元代数、树形构造方式等得以实现与控制。此外,树形聚合物独特的拓扑结构赋予其与线形聚合物不同的温敏行为及脱水机理。本文综述了包括温敏树枝状大分子、温敏树枝化聚合物、温敏超支化聚合物等不同类型温敏树形聚合物近年来的研究进展,重点介绍这些聚合物的合成方法、温敏行为和拓扑结构对温敏行为的影响,以及在纳米材料、生物医用、分子传感器等方面的应用研究。