Grafting of Polystyrene-b-Poly(2-hydroxyethyl methacrylate) onto Carbon Fiber

Carbon fiber (CF) was subjected to oxidation and acyl chlorination, resulting in CF functionalized with acyl chloride (CF-COCl). The block copolymer polystyrene-b-poly (2-hydroxyethyl methacrylate) (PSt-b-PHEMA) was synthesized by atom-transfer radical polymerization (ATRP). According to the reaction between hydroxyl groups of block copolymer and acyl chloride groups on CF, the block copolymer was successfully grafted onto the surface of CF. Fourier-transform infrared spectra (FTIR), Gel permeation chromatography (GPC) were used to determine the chemical structure and molecular weight of block copolymer; Fourier transform infrared spectroscopy-attenuated total reflection (FTIR-ATR), Scanning electron microscopy (SEM) and thermal gravimetric analyses (TGA) were used to determine the chemical property and structure of grafted CF.     

Grafting of poly(ε‐caprolactone) onto maghemite nanoparticles

We report the coating of maghemite (γ‐Fe₂O₃) nanoparticles with poly(ε‐caprolactone) (PCL) through a covalent grafting to technique. ω‐Hydroxy‐PCL was first synthesized by the ring‐opening polymerization of ε‐caprolactone with aluminum isopropoxide and benzyl alcohol as a catalytic system. The hydroxy end groups of PCL were then derivatized with 3‐isocyanatopropyltriethoxysilane in the presence of tetraoctyltin. The triethoxysilane‐functionalized PCL macromolecules were finally allowed to react on the surface of maghemite nanoparticles. The composite nanoparticles were characterized by diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). Effects of the polymer molar mass and concentration on the amount of polymer grafted to the surface were investigated. Typical grafting densities up to 3 μmol of polymer chains per m² of maghemite surface were obtained with this grafting to technique. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 6011–6020, 2004     

聚芳醚腈-聚硅氧烷嵌段共聚物的合成

采用4-烯丙基-2-甲氧基苯酚(Eugenol)为端基的聚二甲基硅氧烷与氟代苯端基含杂萘联苯结构聚芳醚腈,以碳酸钾为催化剂,二甲基亚砜与邻二氯苯为溶剂的条件下进行芳香亲核取代反应(SNAr),合成了一种高分子量的聚芳醚腈-聚硅氧烷嵌段共聚物,并采用FTIR和1H-NMR对该产物的结构进行了表征.DSC测试结果表明该类嵌段共聚物具有两个玻璃化转变温度(Tg),分别为-98～-90℃和255～287℃,而且共聚物具有优良的耐热性,10%的热失重温度(Td)在450℃以上.采用原子力显微镜和透射电镜观测发现该共聚物存在明显的相分离特征.     

Polyimide–polyformal block copolymers

In an effort to combine and tailor the properties of thermoplastic resins we have investigated the synthesis of polyimide–polyformal block copolymers prepared by the condensation reaction of α,ω-diamino functionalized polyformal oligomers with α,ω-dianhydride terminated polyimide oligomers. Amino functionalized polyformal oligomers were synthesized by displacement condensation reactions of various bisphenols with methylene dihalides in the presence of base and aminophenols. Oligomeric aromatic polyformals having weight average molecular weights (MW_w) of 7500 to 40,000 were obtained. Anhydride terminated polyimide oligomers with molecular weights (MW_w) ranging from 10,000 to 15,000 were obtained by the condensation of bisphenol-A–dianhydride and aromatic amines. Combining the polyimide oligomers with the polyformal oligomers in dipolar aprotic or nonpolar solvents afforded the desired block copolymers. The polyimide–polyformal block copolymers generally display two distinct glass transition temperatures by differential scanning calorimetry. The (AB)_n block copolymers were evaluated by TGA in both air and N₂ for thermal/oxidative stability.     

苯乙烯─马来酸酐共聚物／聚硅氧烷纳米尺度复合材料的研究

用溶胶－凝胶方法制备了苯乙烯、马来酸酐和ｒ－缩水甘油丙基醚三甲氧基硅烷复合材料．利用红外光谱、动态力学分析、小角Ｘ－射线散射和原子力显微镜等手段研究了这种材料的结构与性能．结果表明，这种材料以三维网络和纳米微相分离的形式存在，其力学性能和耐热性能较苯乙烯－马来酸酐共聚物有大幅度提高，透明且不溶于丙酮．     

苯乙烯─马来酸酐共聚物／聚硅氧烷纳米尺度复合材料的研究

用溶胶－凝胶方法制备了苯乙烯、马来酸酐和ｒ－缩水甘油丙基醚三甲氧基硅烷复合材料．利用红外光谱、动态力学分析、小角Ｘ－射线散射和原子力显微镜等手段研究了这种材料的结构与性能．结果表明，这种材料以三维网络和纳米微相分离的形式存在，其力学性能和耐热性能较苯乙烯－马来酸酐共聚物有大幅度提高，透明且不溶于丙酮．     

Amine functionalized MCM-41: An active and reusable catalyst for Knoevenagel condensation reaction

This paper reports preparation, characterization of amine modified mesoporous crystalline MCM-41 and its application in Knoevenagel condensation reaction. Amine modified MCM-41 was prepared by co-condensation and post-synthesis methods. The samples were characterized by X-ray powder diffraction, Fourier-transfer infrared spectroscopy (FTIR), thermo gravimetric analysis (TGA), differential thermal analysis (DTA), scanning electron micrograph (SEM), ²⁹Si magic-angle spinning (MAS), nuclear magnetic resonance (NMR), diffuse reflectance spectra (DRS), nitrogen adsorption–desorption and CHN analysis. X-ray diffraction patterns indicate that the modified materials retain the standard MCM-41 structure. SEM study exhibits that the arrangement of particles for 12.8% amine modified MCM-41 is well ordered and spherical in nature. CHN analysis supports that complete hydrolysis of ethoxy groups take place in 12.8% amine modified sample. From the NMR study it is confirmed that the surface coverage is 40% in 12.8% amine modified sample. The base catalytic activity of hybrid MCM-41 materials such as amine (post-synthesis and co-condensation methods) and surfactant functionalized materials for condensation reaction between benzaldehyde and diethyl malonate in solvent free, room temperature synthesis of cinnamic acid was evaluated and correlated with the surface and textural properties. Sample containing 12.8 wt% amine loaded by co-condensation method showed highest malonic ester conversion (92%) and selectivity (98%) for cinnamic acid.     

Environmentally benign preparation of bifunctional cation exchange fibers

A bifunctional cation exchange fiber was prepared by an efficient and environmentally benign method. In this method, sodium p‐styrene sulfonate (SSS) was cografted directly onto the polypropylene (PP) fiber along with acrylic acid (AA), which eliminated the sulfonation process of grafting fiber with concentrated sulfuric acid or chlorosulfonic acid in the conventional method. Effects of the grafting conditions such as reaction temperature, reaction time, pH value, and the influence of acrylic acid and metallic salt on the graft copolymer reaction were investigated. The physicochemical properties of the cation exchange fibers were characterized with diffuse reflectance infrared spectroscopy (FT‐IR), scanning electron microscopy (SEM), X‐ray diffractometer (XRD), thermal gravimetric analysis (TGA), TG‐IR analysis, and monofilament tensile properties test. The experimental results indicate that the optimal conditions of pre‐irradiation grafting are 80°C for 5 hr, and the mechanical properties and thermal stability of the product are better than those of commercial materials (Fiban.K‐1). The total static ion exchange capacity (IEC) of the cationic exchange fiber is up to 5.33 mmol/g. The maximal IEC contribution from the strong acid part is 2.47 mmol/g. This synthetic method provides a clean industrial way for the preparation of bifunctional cation exchange fibers. Copyright © 2009 John Wiley & Sons, Ltd.     

Effect of ammonium groups on the properties and alkaline stability of poly(arylene ether)‐based anion exchange membranes

Five kinds of ammonium groups functionalized partially fluorinated poly(arylene ether) block copolymer membranes were prepared for investigating the structure–property relationship as anion exchange membranes (AEMs). Consequently, the pyridine (PYR)‐modified membrane showed the highest alkaline and hydrazine stability in terms of the conductivity, water uptake, and dry weight. The chloromethylated precursor block copolymers were reacted with amines, such as trimethylamine, N‐butyldimethylamine, 1‐methylimidazole, 1,2‐dimethylimidazole, and PYR to provide the target quaternized poly(arylene ether)s. The structures of the polymers, as well as model compounds and oligomers were well characterized by ¹H NMR spectra. The obtained AEMs were subjected to water uptake and hydroxide ion conductivity measurements and stabilities in aqueous alkaline and hydrazine media. The pyridinium‐functionalized quaternized polymers membrane showed the highest alkaline and hydrazine stability with minor losses in the conductivity, water uptake, and dry weight. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 383–389     

β‐Lactam functionalized poly(isoprene‐b‐ethylene oxide) amphiphilic block copolymers

Amphiphilic block copolymers containing β‐lactam groups on the polyisoprene block were synthesized from poly(isoprene‐b‐ethylene oxide) (IEO) diblock copolymer precursors, prepared by anionic polymerization. β‐Lactam functionalization was achieved via reaction of the polyisoprene (PI) block with chlorosulfonyl isocyanate and subsequent reduction. The resulting block copolymers were molecularly characterized by SEC, FTIR, and NMR spectroscopies and DSC. Functionalization was found to proceed in high yields, altering the solubility properties of the PI block and those of the functionalized diblocks. Hydrogen bond formation is assumed to be responsible for the decreased crystallinity of the poly(ethylene oxide) block (PEO) in the bulk state as indicated by DSC measurements. The self‐assembly behavior of the β‐lactam functionalized poly(isoprene‐b‐ethylene oxide) copolymers (LIEO) in aqueous solutions was studied by dynamic light scattering (DLS), static light scattering (SLS), fluorescence spectroscopy, and atomic force microscopy (AFM). Nearly spherical loose aggregates were formed by the LIEO block copolymers, having lower aggregation numbers and higher cmc values compared to the IEO precursors, as a result of the increased polarity of the β‐lactam rings incorporated in the PI blocks. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 24–33, 2010     

Evaluation of gel permeation chromatography to Fourier transform infrared spectrometric detection using a modified thermospray for analysis of polystyrene samples

A heated gas flow modified thermospray was used to couple gel permeation chromatography (GPC) to Fourier transform infrared spectrometry (FTIR) for the analysis of the standard polystyrene samples. Effluents from the GPC column were evaporated and the solutes were deposited as a series of spots on the surface of a moving stainless steel belt (0.025 mm thickness × 13 mm width). The belt continuously transferred the spots into the diffuse reflectance (DRIFT) accessory of the FTIR spectrometer, enabling identification of the deposited solutes by measurement of the diffuse reflectance IR spectrum. The IR spectra of the separated components showed excellent agreement of the spectral features to those of standard FTIR spectra and no thermal degradation was observed.     

PEO-PET嵌段共聚物的合成及其热行为研究

合成了聚氧化乙烯－聚对苯二甲酸乙二醇酯（PEO－PET）多嵌段共聚物，以红外光谱（RIR）、核磁共振谱图（NMR）对产物进行了结构表征，结果表明产物的组成与理论基本一致；利用差示扫描量效法研究了PEO－PET共聚物的热行为，发现共聚物中软段PEO与硬段PET的结晶性竞相互作用的影响。     

Synthesis,characterization and biological properties of vanadyl(IV) complexes of diclofenac and indomethacin: an experimental and theoretical study

Two new vanadyl(IV) complexes with the non‐steroidal antiinflammatory drugs Indomethacin and Diclofenac were synthesized and characterized by elemental analysis, electronic, diffuse reflectance and FTIR spectroscopies and thermal behavior. The structures of the oxo‐vanadium(IV) complexes were obtained by carrying out ab initio calculations (B3LY/3–21G**) owing to the difficulties of obtaining single crystals of good quality for X‐ray studies. Indomethacin and Diclofenac did not cause any effect when tested on cellular proliferation in two osteoblast‐cell lines in culture (MC3T3E1 and UMR106). The biological effect of the complexes depends on the cellular type and on the nature of the coordinated ligands. Copyright © 2005 John Wiley & Sons, Ltd.     

Evaluation of gel permeation chromatography to Fourier transform infrared spectrometric detection using a modified thermospray for analysis of polystyrene samples

A heated gas flow modified thermospray was used to couple gel permeation chromatography (GPC) to Fourier transform infrared spectrometry (FTIR) for the analysis of the standard polystyrene samples. Effluents from the GPC column were evaporated and the solutes were deposited as a series of spots on the surface of a moving stainless steel belt (0.025 mm thickness × 13 mm width). The belt continuously transferred the spots into the diffuse reflectance (DRIFT) accessory of the FTIR spectrometer, enabling identification of the deposited solutes by measurement of the diffuse reflectance IR spectrum. The IR spectra of the separated components showed excellent agreement of the spectral features to those of standard FTIR spectra and no thermal degradation was observed. Received: 20 May 1996 / Revised: 17 October 1996 / Accepted: 28 November 1996     

In situ oxidative copolymerization and characterization of new poly(benzidine-<Emphasis Type="Italic">co</Emphasis>-<Emphasis Type="Italic">o</Emphasis>-phenylenediamine)/kaolinite microcomposites

Copolymers of benzidine and o-phenylenediamine/kaolinite clay composites with different percentages of kaolinite clay particles were synthesized via in situ oxidative copolymerization. The spectral characteristics upon incorporation of o-phenylenediamine units into the polybenzidine backbone in presence of kaolinite clay were investigated by means of UV–Vis and FTIR spectroscopy. The copolymer in the absence and in the presence of kaolinite clay was studied by thermal gravimetric analysis under non-oxidative conditions. The morphology of the copolymer kaolinite composites system was investigated by the scanning electron microscopy.     

Direct Assembly of Mesoporous Silica Functionalized with Polypeptides for Efficient Dye Adsorption

Herein, we introduce a new polypeptide‐functionalized mesoporous silica template fabricated from a biodegradable poly(ethylene oxide‐b‐?‐caprolactone) (PEO‐b‐PCL) diblock copolymer and a poly(tyrosine) (PTyr) biopolymer. The crystallization behavior of the PEO‐b‐PCL diblock copolymer changes after blending, but the secondary structure of PTry remains stable. After selective solvent extraction in THF, the PEO‐b‐PCL is removed, but PTyr remains within the silica matrix due to its different solubility. Fourier‐transform IR spectroscopic analysis (FTIR), thermal gravitometry analysis (TGA), small‐angle X‐ray scattering (SAXS), and X‐ray diffraction (XRD) studies confirm the retention of PTyr to form a polypeptide‐functionalized mesoporous material. The adsorption of methylene blue hydrate (MB) from aqueous solution into the polypeptide‐functionalized mesoporous silica is investigated, thus revealing that the nanocomposite exhibits a high adsorption capacity relative to pure silica due to hydrogen‐bonding interactions between the hydroxy phenolic group of PTyr and the N‐containing aromatic ring from MB.     

Synthesis and enzymatic degradation of end-functionalized biodegradable polyesters

End-functionalization of biodegradable polymers/oligomers based on L-lactide and glycolide by cholesteryl moiety was investigated. We established the feasibility of preparing the functionalized polymers/oligomers, Chol-(LG)_m+n, through ring-opening copolymerization initiated by cholesterol bearing a hydroxyl group, without adding any catalyst. The functionalized polymers/oligomers of different molecular weights were obtained by controlling the feed ratio of the initiator cholesterol to the monomers. The chemical structure of end-functionalized polymers/oligomers was confirmed by FTIR and ¹H NMR. Incorporation of cholesteryl moiety into the polymer chains induces liquid crystallinity in the resultant oligomers when the molecular chains are not very long. The enzymatic degradation studies, for all the samples, were carried out using enzyme, proteinase K. Interestingly, the enzymatic degradation of cholesteryl end-functionalized polymers/oligomers resulted in a lamella-like porous structure on the sample surface, which is altogether different from the commonly reported spherical-pore structure formed during the degradation of conventional polyesters.     

Synthesis and Characterization of Poly(p-phenylene benzobisoxazole)/Poly(pyridobisimidazole) Block Copolymers

Poly(p-phenylene benzobisoxazole)/poly(pyridobisimidazole) block copolymers (PBO-b-PIPD) were prepared by introducing poly(pyridobisimidazole) (PIPD) moieties into the main chains of poly(p-phenylene benzobisoxazole) (PBO) in order to enhance its photostability. PBO and copolymer fibers were directly prepared from the polymerization solutions by dry-jet wet-spinning. Chemical structures and molecular chains arrangement of the block copolymers were characterized by Fourier transform infrared (FTIR) spectroscopy, solid-state ¹³C-NMR and wide angle X-ray diffraction (WAXD). Thermal stability of the copolymers was investigated by thermogravimetric analysis (TGA) in nitrogen. Thin films of PBO and copolymers were cast from methanesulfonic acid (MSA) solutions. Both the films and fibers were exposed to UV light to determine their photostability. Changes in the chemical structures and surface morphologies of the films were characterized by FTIR spectra and scanning electronic microscopy (SEM), respectively. After UV light exposure, the retention of strength for copolymer fibers is improved compared to PBO fibers. The results revealed that copolymers suffered less photodegradation in comparison with homopolymer. The mechanism for the improved photostability of the copolymers was discussed.     

Polypeptide/Multiwalled carbon nanotube hybrid complexes stabilized through noncovalent bonding interactions

In this study, we used click chemistry to synthesize new linear polypeptide‐g‐pyrene polymers from a mono‐azido‐functionalized pyrene derivative (N₃‐Py) and several poly(γ‐propargyl‐l ‐glutamate) (PPLG) oligomers. Incorporating the pyrene units as side chains enhanced the α‐helical conformations of these PPLG oligomers in the solid state, as determined using Fourier transform infrared (FTIR) spectroscopy; it also increased the temperature stability of the α‐helical secondary structures of the grafted PPLG oligomers, relative to those of the pure PPLG species, as revealed through temperature‐dependent FTIR spectroscopic analyses. In addition, the thermal properties of the PPLG‐g‐Py polypeptides (e.g., glass transition temperatures increased by ca. 100 °C) were superior to those of pure PPLG oligomers. Mixing the PPLG‐g‐Py oligomers with multiwalled carbon nanotubes (MWCNTs) in dimethylformamide led to the formation of highly dispersible PPLG‐g‐Py/MWCNT organic/inorganic hybrid complex materials. Fluorescence emission spectra revealed significant π–π stacking between the PPLG‐g‐Py oligomers and the MWCNTs in these complexes. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 321–329     

Thermische und spektroskopische Untersuchungen zur Wassersorption an Alkalihalogeniden

Investigations on the extension of the diffuse reflectance spectroscopy by means of the dilution method of KORTÜM show the decisive influence of water sorption on the dilution substances, particularly on their absolute reflectance. Water sorption is investigated on alkali halides (NaCl and LiF) as dilution substances by gravimetric, thermal desorption and reflectance methods. Sorption gravimetry gives data on the quantities of adsorbed substances and the time function of adsorption processes, thermal desorption on chemical binding of adsorbed molecules and reflectance spektroscopy on the molar absorptivity of adsorbed water molecules.