In situ preparation,electrospinning, and characterization of polyacrylonitrile nanofibers containing silver nanoparticles

Silver nanoparticles were prepared from a polyacrylonitrile (PAN)/N,N‐dimethylformamide solution of silver nitrate (0.05–0.5 wt %) with light treatment (xenon arc) to reduce Ag⁺ ions into Ag⁰. The formation of silver nanoparticles in the PAN solution and the effect of treatment time on the numbers of silver nanoparticles, their average diameter and size distribution were investigated by UV–visible spectroscopy. In addition, the average size of silver nanoparticles and their shapes in colloidal solution were determined by transmission electron microscopy images and found to be on the order of 10 nm. The resulting solution was electrospun into PAN nanofibers. An increase in the salt concentration led to decreases in the nanofiber diameter and bead numbers (determined by scanning electron microscopy images) and an increase in the crystallinity (confirmed by X‐ray diffraction patterns). A continuous rate of silver release from the nanofiber web was monitored by the atomic absorption technique. These nanofibers showed strong antibacterial activity against Pseudomonas aeruginosa. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Translucent acrylic nanocomposites containing anisotropic laminated nanoparticles derived from intercalated layered silicates

New acrylic nanocomposites consisting of methyl methacrylate (MMA)/n‐dodecylmethacrylate (LMA) copolymers and intercalated layered silicates were prepared. The silicates were based upon bentonite which was rendered organophilic by ion exchange with N,N,N,N,‐dioctadecyl dimethyl ammonium ions. Morphological, thermal, mechanical, and optical properties were examined as a function of both organophilic bentonite and LMA content. Addition of LMA improved the compatibility between the layered silicate and the acrylic matrix, thus promoting bentonite intercalation and formation of anisotropic laminated silicate nanoparticles of an average diameter of 18 nm, average length of 450 nm, and interlayer distance of 4.8 nm, as determined by WAXS, TEM, and AFM. Addition of 2–10 wt % of intercalated layered silicate accounted for improved stiffness/toughness balance, higher glass temperature, and enhanced thermal stability, with respect to the properties of the corresponding MMA/LMA copolymer. As a result of the addition of LMA, translucent acrylic nanocomposites were obtained. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 396–405, 2000     

Synthesis and characterization of poly(methyl methacrylate–butyl acrylate–acrylic acid)/polyaniline core–shell nanoparticles in miniemulsion media

Conductive polymer particles, polyaniline (PANI)‐coated poly(methyl methacrylate–butyl acrylate–acrylic acid) [P(MMA–BA–AA)] nanoparticles, were prepared. The P(MMA–BA–AA)/PANI core–shell complex particles were synthesized with a two‐step miniemulsion polymerization method with P(MMA–BA–AA) as the core and PANI as the shell. The first step was to prepare the P(MMA–BA–AA) latex particles as the core via miniemulsion polymerization and then to prepare the P(MMA–BA–AA)/PANI core–shell particles. The aniline monomer was added to the mixture of water and core nanoparticles. The aniline monomer could be attracted near the outer surface of the core particles. The polymerization of aniline was started under the action of ammonium persulfate (APS). The final product was the desired core–shell nanoparticles. The morphology of the P(MMA–BA–AA) and P(MMA–BA–AA)/PANI particles was characterized with transmission electron microscopy. The core–shell structure of the P(MMA–BA–AA)/PANI composites was further determined by Fourier transform spectroscopy and ultraviolet–visible measurements. The conductive flakes made from the core–shell latexes were prepared, and the electrical conductivities of the flakes were studied. The highest conductivity of the P(MMA–BA–AA)/PANI pellets was 2.05 S/cm. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

原位三元共聚制备高亮度水性铝颜料

为提高铝颜料在水性介质中的耐蚀性能,以丙烯酸(AA)、甲基丙烯酸甲酯(MMA)、甲基丙烯酸丁酯(BMA)为单体,过氧化二苯甲酰(BPO)为引发剂,丙二醇甲醚(PM)为溶剂,通过三元共聚反应在片状铝粉表面包覆致密薄膜,制备了高亮度水性铝颜料。结果表明,当m(丙烯酸)∶m(甲基丙烯酸甲酯)∶m(甲基丙烯酸丁酯)∶m(过氧化二苯甲酰)∶m(丙二醇甲醚)∶m(片状铝粉)=0.083∶0.083∶0.083∶0.015∶40∶1,85℃反应6 h时,水性铝颜料的缓蚀效率为97.2%,涂层光泽度为109.9 Gs。激光粒度分析、SEM和FTIR分析表明,AA、MMA和BMA三种单体通过原位三元共聚在片状铝粉表面形成了致密共聚物薄膜。     

Studies on the synthesis of electrospun PAN‐Ag composite nanofibers for antibacterial application

We have successfully synthesized polyacrylonitrile (PAN) nanofibers impregnated with Ag nanoparticles by electrospinning method at room temperature. Briefly, the PAN‐Ag composite nanofibers were prepared by electrospinning PAN (10% w/v) in dimethyl formamide (DMF) solvent containing silver nitrate (AgNO₃) in the amounts of 8% by weight of PAN. The silver ions were reduced into silver particles in three different methods i.e., by refluxing the solution before electrospinning, treating with sodium borohydride (NaBH₄), as reducing agent, and heating the prepared composite nanofibers at 160°C. The prepared PAN nanofibers functionalized with Ag nanoparticles were characterized by field emission scanning electron microscopy (FESEM), SEM elemental detection X‐ray analysis (SEM‐EDAX), transmission electron microscopy (TEM), and ultraviolet‐visible spectroscopy (UV‐VIS) analytical techniques. UV‐VIS spectra analysis showed distinct absorption band at 410 nm, suggesting the formation of Ag nanoparticles. TEM micrographs confirmed homogeneous dispersion of Ag nanoparticles on the surface of PAN nanofibers, and particle diameter was found to be 5–15 nm. It was found that all the three electrospun PAN‐Ag composite nanofibers showed strong antibacterial activity toward both gram positive and gram negative bacteria. However, the antibacterial activity of PAN‐Ag composite nanofibers membrane prepared by refluxed method was most prominent against S. aureus bacteria. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Nanocomposites of styrene–butadiene rubber and synthetic anatase obtained by a colloidal route and their photooxidation

Photodegradable styrene–butadiene rubber (SBR)/TiO₂ nanocomposites were prepared by a colloidal route through the simple mixing of a commercial polymer latex and synthetic anatase nanoparticles. Stable colloids of pure anatase TiO₂ nanoparticles with an average diameter of 7 nm were prepared by a solvothermal route from the hydrolysis of titanium alkoxide by hydrogen peroxide in the presence of oleic acid. The photocatalytic degradation of the SBR–TiO₂ nanocomposites was carried out in ambient air at room temperature under a UV lamp and was monitored by Fourier transform infrared and UV–visible spectroscopies and differential scanning calorimetry. The results show that the SBR–TiO₂ nanocomposites were photocatalytically degraded under UV light, which indicate that the butadiene chains in the nanocomposite were oxidized during UV irradiation. Thermal analysis measurements indicated that crosslinking reactions occurred. The presence of anatase TiO₂ nanoparticles was found to accelerate the photocatalytic process, and the degradation mechanism was similar to that of the pure SBR polymer. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation of poly(methyl methacrylate‐co‐butyl methacrylate) nanoparticles and their reinforcing effect on natural rubber

Poly(methyl methacrylate‐co‐butyl methacrylate) [P(MMA‐co‐BMA)] nanoparticles were synthesized via emulsion polymerization, and incorporated into natural rubber (NR) by latex compounding. Monodispersed, core‐shell P(MMA‐co‐BMA)/casein nanoparticles (abbreviated as PMBMA‐CA) were produced with casein (CA) as surfactant. The chemical structure of P(MMA‐co‐BMA) copolymers were confirmed by ¹H‐NMR and FTIR analyses. Transmission electron microscopy demonstrated the core–shell structure of PMBMA‐CA, and PMBMA‐CA homogenously distributed around NR particles, indicating the interaction between PMBMA‐CA and NR. As a result, the tensile strength and modulus of NR/PMBMA‐CA films were significantly enhanced. The tensile strength was increased by 100% with 10% copolymer addition, when the molar ratio of MMA:BMA was 8:2. In addition, scanning electron microscopy and atomic force microscopy results presented that the NR/PMBMA‐CA films exhibited smooth surfaces with low roughness, and PMBMA‐CA was compatible with NR. FTIR‐ATR analyses also suggested fewer PMBMA‐CA nanoparticles migrated out of NR. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43843.     

Removal of Cationic Dyes from Aqueous Solution by Hydrophobically Modified Poly(acrylic Acid) Hydrogels

Hydrophobically modified poly(acrylic acid) hydrogels were synthesized using acrylic acid (AA), methyl methacrylate (MMA), ethyl methacrylate (EMA) and butyl methacrylate (BMA) as copolymer monomers. These hydrogels were carried out for removal cationic dyes from aqueous solution. It was found that the adsorption of cationic dye depended on the length of the side chain, hydrophobic monomer (MMA, EMA and BMA) content and pH of the solution. Increasing the hydrophobic monomer content led to an increase in the adsorption of cationic dyes on the hydrogels. The adsorption kinetics and isotherms of hydrogels were in good agreement with pseudo–second-order equation and the Langmuir equation, respectively. The cationic dyes adsorption of hydrogels involved a mechanism that combined swelling and electrostatic and hydrophobic interaction.     

Preparation and properties of electrospun PAN/Fe3O4 magnetic nanofibers

Polyacrylonitrile (PAN)/Fe₃O₄ composite nanofibers were prepared via the electrospinning of the PAN spinning solutions with magnetite Fe₃O₄ nanoparticles. The experimental results showed that the morphology and diameter of the nanofibers strongly depended upon concentrations of PAN and salt additives in the spinning solutions. A suitable PAN concentration and LiCl additives could effectively prevent the occurrence of beads in the electrospinning process and affected the diameters of the electrospun nanofibers. The breaking strength and breaking strain decreased when the magnetite Fe₃O₄ nanoparticles were incorporated. The prepared PAN/Fe₃O₄ nanofibers were superparamagnetic at room temperature. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation of atactic poly(vinyl alcohol)/silver composite nanofibers by electrospinning and their characterization

Poly(vinyl alcohol) (PVA)/silver composite nanofibers were successfully prepared by the electrospinning method. Water‐based colloidal silver in a PVA solution was directly mixed without any chemical or structural modifications into PVA polymer fibers to form organic–inorganic composite nanofibers. The ratio of silver colloidal solution to PVA played an important role in the formation of the PVA/silver composite nanofibers. We prepared two different atactic PVA/silver nanocomposites with number‐average degrees of polymerization of 1700 and 4000 through electrospinning with various processing parameters, such as initial polymer concentration, amount of silver colloidal solution, applied voltage, and tip‐to‐collector distance. The PVA/silver composite nanofibers were characterized by field emission scanning electron microscopy and transmission electron microscopy (TEM). TEM images showed that silver nanoparticles with an average diameter of 30–50 nm were obtained and were well distributed in the PVA nanofibers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation and properties of transparent PMMA/ZrO2 nanocomposites using 2-hydroxyethyl methacrylate as a coupling agent

Transparent PMMA/ZrO₂ nanocomposites were prepared by in-situ bulk polymerization of methyl methacrylate (MMA)/ZrO₂ dispersions that were firstly synthesized using nonaqueous synthesized ZrO₂ nanocrystals and the function monomer, 2-hydroxyethyl methacrylate (HEMA), as the ligand. The dispersion behavior of ZrO₂ nanoparticles in MMA, structure, mechanical and thermal properties of the PMMA/ZrO₂ nanocomposites were investigated comprehensively. It was found that ZrO₂ nanoparticles were well dispersed in MMA with HEMA ligand, but the MMA/ZrO₂ dispersions easily destabilized in air as well as at elevated temperatures. The destabilization temperature of the dispersion is raised by increasing the molar ratio of HEMA/ZrO₂ to match the bulk polymerization temperature. The PMMA/ZrO₂ nanocomposites showed an interesting chemical structure (namely, highly cross-linked structure even at ZrO₂ content as low as 0.8 wt% and hydrogen bonding interaction between polymer matrix and ZrO₂ nanoparticles), with enhanced rigidity without loss of the toughness and improved thermal stability. The relationship between the structure and the properties of the PMMA/ZrO₂ nanocomposites based on the HEMA coupling agent was discussed.     

Preparation of Mesoporous Carbons from Acrylonitrile-methyl Methacrylate Copolymer/Silica Nanocomposites Synthesized by in-situ Emulsion Polymerization

Acrylonitrile-methyl methacrylate (AN-MMA) copolymer/silica nanocomposites were synthesized by in-situ emulsion polymerization initiated by 2,2'-azobis(2-amidinopropane) dihydrochloride absorbed onto colloidal silica particles, and the mesoporous carbon materials were prepared through carbonization of the obtained AN-MMA copolymer/silica nanocomposites, followed by HF etching. Thermogravimetric analysis of AN-MMA copolymer/silica nanocomposites showed that the carbon yield of copolymer was slightly decreased as silica particle incorporated. N₂ adsorption-desorption, scan electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize the structure and morphology of the mesoporous carbon materials. Both SEM and TEM results showed that disordered mesopores were formed in the obtained carbon material mainly through templating effect of silica nanoparticles. The diameter of mesopores was mainly distributed in the range from 5 nm to 15 nm. The mean pore diameter and total pore volume of the material increased as the mass fraction of silica in the nanocomposites increased from 0 to 24.93%. The significant increase of the mean pore diameter and the decrease of surface area for the carbon material prepared from the nanocomposite with 24.93% silica were caused by partial aggregation of silica nanoparticles in the polymer matrix.     

Photocatalytic Deposition of Silver Nanoparticles onto Organic/Inorganic Composite Nanofibers

Summary: In this work, silver nanoparticles were embedded in electrospun organic/inorganic composite nanofibers consisting of PAN and TiO₂ through photocatalytic reduction of the silver ions in silver nitrate solutions under UV irradiation. The morphology and diameter of PAN/TiO₂ composite nanofibers could be controlled by varying the initial contents of TiO₂ in the spinning solution. From TEM images and UV‐Vis spectra, it has been confirmed that monodisperse silver nanoparticles with a diameter of ≈2 nm were deposited selectively upon the titania of the as prepared composite nanofibers. The amount of Ag nanoparticles embedded on composite nanofibers was greatly influenced by the amount of TiO₂ in composite nanofibers, reflecting the role of titania as the inorganic stabilizer and photocatalyst.

Morphology of silver nanoparticles embedded on PAN/TiO₂ composite nanofibers.     

Synthesis of silver nanoparticles in electrospun polyacrylonitrile nanofibers using tea polyphenols as the reductant

Uniformly dispersed Ag nanoparticles (AgNPs) with diameter about 5 nm embedded in electrospun polyacrylonitrile (PAN) nanofibers were synthesized by using tea polyphenols (TP) as the reductant. The reducing ability of TP toward Ag ions was characterized by Fourier transform infrared spectroscopy and ultraviolet–visible spectra, and the results revealed that TP exhibit satisfied reducing ability in the synthesis process. Transmission electron microscopy observation showed that the synthesized spherical AgNPs with diameter about 5 nm were immobilized on the surface and in the interior of PAN nanofibers by electrospinning technology. The interactions of Ag with PAN and TP were investigated by X‐ray photoelectron spectroscopy (XPS), and the results suggested that PAN polymer and TP both served as stabilizer during the synthesis of AgNPs because of the chelating interactions of Ag with cyano groups and phenolic hydroxyls. The synthesized AgNPs in PAN nanofibers exhibit good antibacterial property and may be used for antibacterial and catalytic applications. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers     

含3nm硅溶胶的苯丙杂化乳液的制备与性能研究

在单一乳化剂存在下 ,用原位分散聚合方法制备了含 3 nm硅溶胶的苯丙杂化乳液。通过 FTIR、粒径分析、ζ电位和流变性能测试 ,表征了杂化乳液中的杂化效应、微粒形态及乳液稳定性 ,并与分别由 3 nm和 1 0 nm硅溶胶与苯丙乳液直接共混形成的杂化乳液进行了比较。与直接共混的杂化乳液成膜后的力学性能相比 ,由原位分散聚合形成的 3 nm硅溶胶杂化乳液成膜后 ,显示出较高的拉伸强度、拉伸模量和断裂伸长率。     

Preparation and properties of chitosan‐graft‐poly(methyl methacrylate) nanoparticles using potassium diperiodatocuprate (III) as an initiator

Graft copolymer nanoparticles prepared from chitosan (CS) and methyl methacrylate (MMA) monomer were synthesized in aqueous solution by using potassium diperiodatocuprate [Cu(III)] as an initiator and characterized in terms of particle size, zeta potential, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy, thermal stability, and X‐ray diffraction spectrometry. The results indicated that CS was covalently linked to poly(methyl methacrylate) (PMMA), and the resulting copolymers formed nanoparticles. These nanoparticles [prepared at 35°C, in a weight ratio of MMA/CS of 5 : 1 and with a Cu(III) concentration of 1.5 × 10⁻³ mol/L] were 54–350 nm in size, with a mean hydrodynamic diameter of 183 ± 3 nm and were highly uniform in particle‐size distribution, with a rather spherical shape and an obvious positive charge surface. The effect of reaction conditions such as Cu(III) concentration, reaction temperature, and the weight ratio of MMA/CS on the mean particle size was also investigated. Insulin‐loaded nanoparticles were prepared, and their maximal association efficiency was up to 85.41%. The experiment of release in vitro showed that the nanoparticles gave an initial burst release followed by a slowly sustained one. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis of CdS‐ and ZnS‐modified bentonite nanoparticles and their applications to the degradation of eosin B

BACKGROUND: In the present study, nanocomposites of cadmium sulphide (CdS) and zinc sulphide (ZnS) on a bentonite have been prepared via an in‐situ precipitation route and their catalytic behaviour was evaluated in the degradation of eosin B. RESULTS: It was found that the basal space of bentonite increased from 1.23 to 1.49 nm after CdS or ZnS nanoparticles were deposited on layers of the bentonite. The resulting CdS–bentonite and ZnS–bentonite nanocomposites can degrade eosin B from aqueous solution after 2 h under UV irradiation. CONCLUSION: A soft method for in situ synthesis of monodispersed, CdS and ZnS nanoparticles, using a reverse micelle type procedure, is reported. The synthesized CdS‐ and ZnS–bentonite composites combined the adsorptive ability of bentonite and the catalytic degradation ability of CdS and ZnS to remove eosin B from its aqueous solution efficiently. Copyright © 2009 Society of Chemical Industry     

Synthesis, Optical Properties, and Photocatalytic Activity of One-Dimensional CdS@ZnS Core-Shell Nanocomposites

One-dimensional (1D) CdS@ZnS core-shell nanocomposites were successfully synthesized via a two-step solvothermal method. Preformed CdS nanowires with a diameter of ca. 45 nm and a length up to several tens of micrometers were coated with a layer of ZnS shell by the reaction of zinc acetate and thiourea at 180 °C for 10 h. It was found that uniform ZnS shell was composed of ZnS nanoparticles with a diameter of ca. 4 nm, which anchored on the nanowires without any surface pretreatment. The 1D CdS@ZnS core-shell nanocomposites were confirmed by XRD, SEM, TEM, HR-TEM, ED, and EDS techniques. The optical properties and photocatalytic activities of the 1D CdS@ZnS core-shell nanocomposites towards methylene blue (MB) and 4-chlorophenol (4CP) under visible light (λ > 420 nm) were separately investigated. The results show that the ZnS shell can effectively passivate the surface electronic states of the CdS cores, which accounts for the enhanced photocatalytic activities of the 1D CdS@ZnS core-shell nanocomposites compared to that of the uncoated CdS nanowires.     

Synthesis of poly(methyl methacrylate)/silica nanocomposite through emulsion polymerization using dimethylaminoethyl methacrylate

Polymer/Silica nanocomposite latex particles were prepared by emulsion polymerization of methyl methacrylate (MMA) with dimethylaminoethyl methacrylate (DM). The reaction was performed using a nonionic surfactant and in the presence of silica nanoparticles as the seed. The polymer‐coated silica nanoparticles with polymer content and number average particle sizes ranged from 32 to 93 wt % and 114–310 nm, respectively, were obtained depending on reaction conditions. Influences of some synthetic conditions such as MMA, DM, surfactant concentration, and the nature of initiator on the coating of the silica nanoparticles were studied. Electrostatic attraction between anionic surface of silica beads and cationic amino groups of DM is the main driving force for the formation of the nanocomposites. It was demonstrated that the ratio of DM/MMA is important factor in stability of the system. The particle size, polymer content, efficiency of the coating reaction, and morphology of resulted nanocomposite particles showed a dependence on the amount of the surfactant. Zeta potential measurements confirmed that the DM was located at the surface of the nanocomposites particles. Thermogravimeteric analysis indicated a relationship between the composition of polymer shell and polymer content of the nanocomposites. The nanocomposites were also characterized by FTIR and differential scanning calorimetry techniques. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

丙烯酰胺/丙烯酸/甲基丙烯酸甲酯双水相共聚过程的成滴机理

在含聚丙烯酸钠（PAANa）的硫酸铵（AS）水溶液中,进行丙烯酰胺（AM）/丙烯酸（AA）/甲基丙烯酸甲酯（MMA）双水相共聚合反应,制备阴离子型聚丙烯酰胺水溶性聚合物分散液。采用动态激光光散射（DLS）在线检测了双水相聚合初期液滴形成及生长规律,发现液滴在反应初期存在聚并现象,滴径分布先变宽后变窄。采用气相色谱检测了共聚过程中各单体的残余量,推算聚合物链结构组成：反应前期聚合物链以AM和MMA链节为主,反应中期聚合物链以AM链节为主,反应后期聚合物链以AA和AM链节为主。提出了AM/AA/MMA双水相共聚过程的成滴机理,其中聚合物链上AA链节所带有的负电荷是聚合产物稳定分散、不易于凝聚的重要因素。