Synthesis,characterization, and bactericidal properties of composites based on crosslinked resins containing silver

Two different commercial crosslinked resins (Amberlite GT73 and Amberlite IRC748) were employed for anchoring silver. The ? SH and ? N(CH₂COOH)₂ groups, respectively, present on these resins were used for Ag⁺ chelation from an aqueous solution. The Ag⁺ ions were reduced with three different reductants: hydrazine, hydroxylamine, and formaldehyde (under an alkaline pH). The produced composites were characterized with thermogravimetry/differential thermogravimetry and scanning electron microscopy combined with a backscattered scanning electron detector. Energy‐dispersive X‐ray spectroscopy coupled to scanning electron microscopy allowed the observation of submicrometer particles of silver, and chemical microanalysis of emitted X‐rays revealed the presence of metal on the internal and external surfaces of the composite microspheres. The amount of incorporated silver was determined by titration. The antibacterial activity of the silver/resin composites was determined toward 10³–10⁷ cells/mL dilutions of the auxotrophic AB1157 Escherichia coli strain; the networks containing anchored submicrometer silver particles were completely bactericidal within a few minutes because of the combined action of silver and functional groups of the resins. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and properties of superabsorbent hydrogels based on guar gum and succinic anhydride

Synthesis of novel superabsorbent hydrogels has been investigated with the reaction of guar gum and succinic anhydride (SA), using of 4‐dimethylaminopyridine as esterification promoter and water or dimethylsulfoxide (DMSO) as reaction solvent, followed by NaOH neutralization. Hydrogels prepared in water exhibited somewhat higher water absorbency than those prepared in DMSO; its maximum water absorbency in pure water and aqueous 0.9% NaCl solution was ca. 200 g/g and 80 g/g, respectively. These values were considerably higher than those of hydrogels obtained from starch in a similar way. The products in this study biologically degraded up to 70–80% after 10 days in activated sludge, which shows their excellent biodegradability. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Properties of polyacrylamide‐based hydrogels prepared by electron beam irradiation for possible use as bioactive controlled delivery matrices

Polyacrylamide/poly(ethylene oxide) (PAAm/PEO) crosslinked hydrogels were designed for controlled delivery of an herbicide, Atrazine, which is used in the agricultural field. Atrazine was incorporated into a PAAm/PEO matrix during an electron beam irradiation process. The Atrazine release rate from matrices prepared under different conditions was studied to determine which factors have the most affect and control over the PAAm/PEO matrix release property. The copolymer blend composition, copolymer gel content, and irradiation dose greatly affected the Atrazine release rate. In addition, its release rate was influenced by the pH and temperature of the matrix‐surrounding medium. The Atrazine release rate decreased as the pH increased, but it increased as the temperature increased. The properties of the prepared crosslinked hydrogels may make them acceptable for practical use as bioactive controlled release matrices. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1262–1270, 2005     

Preparation and properties of hydrogels based on hemicellulose

Xylan with glucuronic acid functionalities, separated from birchwood, was converted into hydrogels by dissolving it together with chitosan in acidic conditions. The hydrogels were formed at certain xylan/chitosan compositions. The mechanism of the gel formation was investigated with FTIR. Complexation between glucuronic acid functionalities of xylan and amino groups of chitosan is suggested to be responsible for network formation. The swelling behavior of these hydrogels was studied at various pH levels and salt concentrations, and the hydrogels responded in a reversible manner to various stimuli. DMA of the films showed separated transitions that may correspond to different phases. Imaging with AFM in TappingMode™ of the surfaces indicated discrete xylan and chitosan phases. A sponge-like microporous structure, as shown with SEM, was formed when a hydrogel was freeze dried. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 1661–1667, 1998     

Synthesis,photophysical properties,and application of optical brighteners based on stilbene-oxadiazole derivatives

A series of symmetrical optical brighteners based on stilbene-oxadiazole derivatives were prepared by the simple synthetic route of a condensation reaction between 4,4′-dicarboxystilbene and N,N′-carbonyldiimidazole reagent, forming stilbene 4,4′-ethene-1,2-diyldibenzohydrazide as a key intermediate. The obtained compounds were characterised by analysis of nuclear magnetic resonance, mass spectrometry, and elemental analysis data. The absorption maximum wavelength, fluorescence emission wavelength, and fluorescence quantum yield were measured in N,N-dimethylformamide solution at room temperature, and the fluorescence properties of the prepared compounds in the solid state were observed and measured. The compounds exhibited bluish and greenish fluorescence emission, with the fluorescence quantum yield in the range 0.2–0.8; the effects of substituents on the emission spectra of these compounds were interpreted. The prepared compounds were applied as optical brighteners to polyester and polyamide-6 fabrics at various concentrations, and their CIE whiteness index and fastness properties were studied.     

Characterization and adsorption properties of the chelating hydrogels derived from natural materials for possible use in the improvement of groundwater quality

A new carrageenan based chelating copolymer sorbent was prepared by gamma radiation induced copolymerization and crosslinking of kappa‐carrageenan (k‐Car) and acrylic acid (AAc). The swelling characteristics of the prepared copolymer were investigated by studying the effect of time, pH, and ionic strength of the swelling medium. The sorption capacities of the chelating copolymer for Fe, Pb, Mn, Zn, Cu, Sr, Cd, and Al were 172, 202, 202, 216, 221, 230, 239, and 244 mg/g respectively. The Freundlich and Langmuir adsorption isotherms were used to validate the metal uptake data and heats of adsorption for the investigated metal ions were calculated. The re‐use experiment showed that the prepared hydrogel could be regenerated upto at least 10 times. Because of the promising data collected from bench scale experiments, the prepared copolymer was examined as chelating sorbent to improve the quality of some groundwater resources. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Sustainable synthesis of bio‐based hyperbranched ester and its application for preparing soft polyvinyl chloride materials

In this study, bio‐based hyperbranched ester was synthesized from castor oil. The chemical structure of the bio‐based hyperbranched ester obtained was characterized with Fourier transform infrared and ¹H NMR spectra. Soft polyvinyl chloride (PVC) materials were prepared via thermoplastic blending at 160 °C using bio‐based hyperbranched ester as plasticizer. The performances including the thermal stability, glass transition temperature (T_g), crystallinity, tensile properties, solvent extraction resistance and volatility resistance of soft PVC materials incorporating bio‐based hyperbranched ester were investigated and compared with the traditional plasticizer dioctyl phthalate (DOP). The results showed that bio‐based hyperbranched ester enhanced the thermal stability of the PVC materials. The T_g of PVC incorporating bio‐based hyperbranched ester was 23 °C, lower than that of PVC/DOP materials at 28 °C. Bio‐based hyperbranched ester showed a better plasticizing effect, solvent extraction resistance and volatility resistance than DOP. The plasticizing mechanism is also discussed. © 2018 Society of Chemical Industry     

Preparation,characterization, and release properties of hydrogels based on hyaluronan for pharmaceutical and biomedical use

Hyaluronic acid (HA) is a natural polysaccharide that is widely distributed in the human body. Its physicochemical properties and high biocompatibility make it a good candidate for biomedical and pharmaceutical uses. In the present work, we report HA‐based hydrogels that could be applied as drug delivery systems or as implants for the treatment of joint diseases. We use butanediol diglycidyl ether as a chemical crosslinker to obtain HA hydrogels. Using a new dissolution tester and ketoprofen (KP) as a model drug, we study the release properties of the hydrogels. We obtain homogeneous and transparent hydrogels with high strength and elasticity. The swelling ratio (SR) depends on the crosslinker concentration and pH of the medium. We also reveal differences between the release profile of KP from swollen and unswollen hydrogels. The characteristics and differences in KP release profiles depending on the SR suggest the possibility of obtaining controlled release from HA‐based hydrogels. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1377‐1382, 2013     

Synthesis and electrochemical properties of phloroglucin‐based ferrocenyl compounds and their application in anion recognition

Phloroglucin‐based ferrocenyl compounds, including hyperbranched phloroglucin‐based ferrocenyl polymer and phloroglucin‐based ferrocenyl dendrimer (Generation0), were prepared by a convenient approach. Cyclic voltammograms were used to investigate their electrochemical properties, and we found that the scanning rate and solvent had remarkable effects on electrochemical behavior of the compounds. These compounds showed electrochemical responses to the anions, and a selective recognition for H₂PO over other anions was observed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and properties of dispersed hybrid materials based on a silicate matrix

Modification of alkali-silicate solutions of polyvalent metal salts and an organic oligomer (Epoxydan resin ED-20) has been performed. Dispersed metal-silicate and metal-epoxy-silicate products have been obtained, and their structure and physical-chemical properties have been investigated. It has been demonstrated that the developed dispersed organosilicate products could be used as functionally active fillers of superhigh molecular weight polyethylene (SHMWPE) and Phenylon (an analogue of Nomex) S-2. It has been established that the composite nanostructure and physical-mechanical properties depend on the type of polyvalent metal impregnated into the epoxysilicate matrix.     

Soluble network polymers based on trifluoropropyl-substituted open-cage silsesquioxane: Synthesis,properties, and application for surface modifiers

Fluorinated completely condensed polyhedral oligomeric silsesquioxanes (F-CC-POSSs) are widely utilized as surface modifiers for polymeric materials because of their polyhedral and fluorine-rich structures, which generate polymers with lower surface energies under molecular-level control. In contrast, their derivatives, fluorinated incompletely condensed or open-cage POSSs (F-IC-POSSs), have similarly intriguing structures, but their utilization for polymer synthesis remains undeveloped. Herein, fluorinated network polymers were prepared based on a 3,3,3-trifluoropropyl-substituted IC-POSSs via hydrosilylation polymerization with isobutyl- and phenyl-substituted IC-POSS under optimized conditions. In addition to their good thermal stability and tunable refractive indices, these polymers exhibited solution processability and their casting films showed excellent optical transparency, indicating their potential for constructing fluorinated polymers. Their utilization as surface modifiers was examined by addition to poly(methylmethacrylate) (PMMA) films. Intriguingly, modified PMMA films with 2.0 and 0.5 wt% addition showed similar hydrophobicity and surface energies to the films prepared with only fluorinated network polymers.     

基于1,3,6,8-四甲基咔唑热活化延迟荧光材料的合成及发光性质

本文以1,3,6,8-四甲基咔唑（TMCz）为给体,1,3,4-噁二唑（OXD）和1,3,4-噻二唑（THD）为受体,设计合成了两例发光材料,即TMCz-OXD和TMCz-THD。利用紫外-可见吸收光谱、发射光谱、电化学分析等手段对其光物理、电化学以及电致发光性质进行了研究。实验表明,TMCz的1,8位甲基的空间位阻能有效增大给受体之间的二面角（86°）。TMCz-OXD和TMCz-THD的掺杂膜中均表现出热活化延迟荧光（TADF）性质,相应电致发光的最大外量子效率（EQE）分别为6.5%和6.4%。TMCz可作为蓝光TADF材料的普适性给体,广泛应用于有机光致/电致发光材料以及有机发光二极管等领域。     

Synthesis and properties of nanocomposite materials based on ultra-high-molecular-weight polyethylene and graphite nanoplates

A method for the synthesis of nanocomposite materials based on ultra-high-molecular-weight polyethylene and graphite nanoplates via polymerization filling is developed. Polyethylene formed during the synthesis evenly coats individual nanoplates; as a result, there is a uniform distribution of graphite nanoplates in the polymeric matrix. It is shown that the introduction of graphite nanoplates results in significant increases of the elastic modulus and deformation heat resistance and causes a sharp decrease in the gas permeability of the material.     

Synthesis and characterization of aluminum citrate compounds and evaluation of their influence on the formation of hydrogels based on polyacrylamide

Aluminum citrate is used as a conformance control agent to improve oil production and excess water production. This paper discusses the formation of mono and polynuclear aluminum species from the synthesis of aluminum citrate and evaluates these compounds as crosslinkers in hydrogels for conformance control. The products obtained from the synthesis were characterized by Fourier-transform infrared spectrometry (FTIR), elemental analysis (CHN), scanning electron microscopy (SEM), and inductively coupled plasma–optical emission spectrometry (ICP-OES). The FTIR analyses indicated the presence of mononuclear aluminum citrate complexes at pH 3 and polynuclear species starting at pH 4. These results were corroborated by CHN and ICP-OES techniques, which revealed the variation of carbon, oxygen, hydrogen, and alumina precipitate levels as functions of pH variation. The focus of the study was to assess how these crosslinking agents perform in hydrogel formation under reservoir conditions. Rheological analysis showed that the values of tan (delta) of the hydrogel synthesized with aluminum citrate at pH 6 were lower than 0.1, indicating strong gels, while at pH 9, the values were above 0.1, indicating weak gels. These results are in agreement with those obtained by FTIR, which showed that at pH 6, the structures of the aluminum citrate complex were probably in the form [Al₃(C₆H₅O₇)₃(OH)₄(H₂O)]⁴⁻. This structure appears to allow easier access to the aluminum orbital for the crosslinking process compared to the gel composed of aluminum citrate synthesized at pH 9 [Al₃(C₆H₆O₇)₃(OH)₄(H₂O)₅]⁴⁻.

     

Synthesis, properties and application of high conductive LaCrO3-based ceramic materials

The synthesis of LaCrO₃ and LaCrO₃-based materials by the hydrothermal method and in air has been investigated. In respect to the synthesized products, the structure and a number of physical properties, such as electrical and magnetic properties, are discussed. The authors utilized the doped LaCrO₃ material as various “conducting leads” for ZrO₂-based heating elements to substitute the expensive Pt-Rh wire. The working temperature of these elements can be up to 2000–2100°C in oxidizing atmosphere.     

Thermoreversible hydrogels. XVIII. Synthesis,swelling characteristics,and diffusion behaviors of porous,ionic, thermosensitive hydrogels

Porous, ionic, thermosensitive hydrogels were prepared from N‐isopropylacrylamide, a cationic monomer [trimethyl (acrylamido propyl) ammonium iodide (TMAAI)], an anionic monomer [acrylic acid (AA)], a zwitterionic monomer [N′,N′‐dimethyl (acrylamido propyl) ammonium propane sulfonate], or a nonionic monomer [poly(ethylene glycol) methyl ether acrylate], and a pore‐forming agent [poly(ethylene glycol) (PEG)] of different molecular weights. Some fundamental properties and dynamic swelling kinetic parameters and solute permeation for these porous gels were investigated. The results showed that the gel containing the cationic monomer TMAAI had a higher equilibrium swelling ratio. The diffusion coefficients showed that the swelling rates for the gels with the anionic monomer AA and PEG with a higher molecular weight (20,000) were faster. The results showed that the fast swelling–deswelling behavior for the porous structure gels was due to them being more available than the gels with long hydrophilic side chains. In addition, the interactive force between the solutes and gels and the solute permeation through the porous gels were investigated. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2214–2223, 2003     

Synthesis and characterization of superabsorbent hydrogels composites based on polysuccinimide

A kind of novel superabsorbent hydrogel with high swelling ratio property that could be used for the development of water absorbing resin, soil water retention agent, and chemical sand‐fixing material was synthesized in this study. The hydrogels were prepared by the crosslinking reaction of polysuccinimide (PSI). The relationships between swelling ratio and volume of solvent as well as the concentration of crosslinking agent were investigated in detail. Several composites, such as starch, carrageenan, and polyacrylamide, were added into hydrogels to enhance the swelling ratio. It was found that the swelling ratio was significantly increased, which the maximum water absorbency was enhanced 2.46 times when the composite polyacrylamide (PAM) was added compared to the control. The effects of ionic strength and sensitivity of pH on hydrogels were also studied. The modified hydrogels products with swelling ratio less sensitivity to the salinity as well as relative high swelling ration in salinity system were also obtained by adding PAM. Through the Fourier transform infrared spectroscopy (FTIR) characterizations, the crosslinking reaction mechanism and the structure of composite were proposed. In addition, the transmission electron microscopy (TEM) examinations showed that some composite materials elevated the physical crosslinked and connected channels density substantially. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 550–557, 2006     

Polyaniline: Synthesis,properties, and application

The methods of synthesis and the properties of polyaniline—a representative of the family of conducting polymers—are reviewed briefly. It is shown that variation in the conditions of aniline polymerization makes it possible to synthesize polymer materials with the desired structures and properties and, thus, to provide for the use of polyaniline in various fields of science and engineering. Special attention is given to the matrix synthesis of polyaniline as the main approach to obtain electroactive and conducting composite materials. The use of polyaniline and the related composite materials in polymer electronics is analyzed briefly.     

可降解材料相容剂的合成及其应用

采用自制的丙烯酸十八酯一马来酸酐共聚物作为相容剂,以聚丙烯为基材,通过填充淀粉和CaCO3以及加入光敏剂,用机械熔融共混的方法制成了可生物降解和光降解的复合物,并用红外光谱对复合物进行了表征．对该复合物的力学性能、热性能和耐老化性能等进行了测试分析。结果表明,加入填料后,复合物的力学性能下降．淀粉和CaCO3总质量分数不宜超过60％;复合物的熔点随填料量的增加而降低;加入光敏剂起到了预想光降解的效果。     

Synthesis and application of abrasion resistant coating materials based on functionalized bis and tris maleimides

Trialkoxysilane functionalized bis and trismaleimide based systems have been synthesized and used for coating a bisphenol-A polycarbonate substrate by the sol-gel method. The abrasion resistance of the substrate is improved by the optically clear materials following thermal curing of the coating.