bluuebunny/crossref_metadata_2025 huggingface dataset:
Predicting flow induced change in phase diagram of polymer solutions in simple shear flow
Authors: Mazinani Saeedeh , Sharif Farhad , Mohammadi Naser
Published: August 2014

The change in the phase diagram of polymer mixtures under flow is an important issue since flow may promote mixing or demixing of the phases in a polymer mixture. This work, compared to previous studies, presents a different approach with special attention to the rheology of polymer solutions and flow conditions. Different approaches including Marrucci's approach in calculating stored elastic free energy (ΔGE) have been reviewed. Marrucci’s equation is obtained based on a fundamental analysis of polymer chains microstructure. The new approach introduces the proper viscoelastic constitutive equations to estimate ΔGE. Selecting the appropriate rheological model is essential to correctly estimate the state of stress and deformation rates due to the flow. Moreover, the parameters of viscoelastic constitutive equations were defined, from the microstructural viewpoint, as functions of composition and temperature in semi-concentrated regions. Finally, flow induced change in the phase diagram of polymer solutions is predicted for a well-defined flow condition (constant shear rate and stress), and the results are compared with the previously reported experimental observations of mixing and demixing.
Anionic polyacrylamide “water-in-water” emulsion prepared by dispersion polymerization in mixed salt aqueous media
Authors: Lü Yongli , Feng Yujun , Zhao Yongfeng , Zhang Sheng , Shu Songkuang , Luo Pingya
Published: August 2014

Polyacrylamide “water-in-water” emulsion was regarded as a new generation of water-soluble polymeric materials and has attracted much attention from both academia and industry because of its environmentally-friendly character. Anionic polymeric “water-in-water” emulsions prepared by dispersion polymerization of acrylamide (AM) and sodium acrylic acid (NaAA) in mixed solution of Na2SO4 and (NH4)2SO4 are reported in this paper, and the parameters influencing polymerization and the final dispersion stability, including, N2 flow rate, chain transfer agent content, inorganic salt content, and the molar ratio of AM to NaAA were examined and opitimized. It was found that the intrinsic viscosity of resulting copolymers decreased as the N2 flow rate and CTA concentration increased, and the resultant dispersions with 27 % ∼ 28 % inorganic salt have regular particle shape, lowest particle size, better flowability and storage stability. The salt level in the reaction system would also dominate the time that the dispersion formed, and the ratio of AM to NaAA would influence the total monomers conversion and polymerization rate.
Hyperbranched poly(amine-ester) polyol: Synthesis, characterization, thermal stability, solubility and surface activity
Authors: Xuechuan Wang , Xuzheng Yuan , Taotao Qiang , Xing Chen
Published: August 2014

A series of hyperbranched poly(amine-ester) polyols were synthesized by the polycondensation of N,N-diethylol-3-amine-methylpropionate [prepared by the Michael addition reaction of methyl acrylate (MA) with diethanolamine (DEA)] as an AB2-type monomer with trimethylol propane (TMP) as the core moiety, proceeding in one-step procedure in the melt with p-toluenesulfonic acid (p-TSA)as catalyst. The Michael addition reaction and polycondensation behaviors were systematically investigated, in an effort to optimize the reaction conditions, respectively. Optimum parameters for addition reaction: at MA/DEA ratio of 2:1 for 4 h at 35 °C, adding MA to DEA, using methyl alcohol as solvent; and for polymerization: dosage of p-TSA was 2 wt % (based on total weight of AB2-type monomer and core) for 4~5 h at 120 °C, adding monomer to core. The obtained monomer and polymers were characterized by Fourier transform infrared spectroscopy (FTIR), 1H-NMR spectroscopy and gel permeation chromatography (GPC). It was suggested that the hyperbranched poly(amine-ester) polyol formed via a mechanism of a combination of transesterification and addition reactions. The thermal stability, solubility and surface activity in aqueous solution of the polymers were also examined.
Influence of side chain lengths of graft copolymers on compatibilization of homopolymer a/homopolymer b/graft copolymer ternary blends: a Monte Carlo Simulation
Authors: Zhu Yutian , Shi Dean , Jiang Wei , Yiu Li Robert Kwok
Published: August 2014

The Monte Carlo method was used to investigate the effect of graft length and architecture on the efficiency of compatibilization in A/B/graft copolymer ternary blends. In this study, homopolymer B is always dispersed phase. When the graft length of the copolymer is relatively short, A20Bn copolymers (A block is the backbone, and B block is the graft) tend to form micelles in the matrix phase, whereas the B20An (B block is the backbone, and A block is the graft) copolymers tend to form micelles in the dispersed phase. We also find that the micelles in the dispersed phase (formed by B20An copolymers) can effectively suppress the coalescence of the dispersed phases, whereas the micelles in matrix phase (formed by A20Bn copolymers) have no effect on suppressing the coalescence. As a result, when the graft length is relatively short, B20An copolymers can lead to smaller dispersed phases than A20Bn copolymers. Moreover, when the graft is relatively long, A20Bn copolymers were found to connect the dispersed phases and form netlike structure, whereas B20An copolymers were found to locate at the phase interface and anchor the dispersed phase and matrix phase. Furthermore, both A20Bn and B20An copolymers with relatively long graft lengths can well reduce the size of the dispersed phase.
Facile synthesis of fluorescent ABA type amphiphilic triblock copolymers via RAFT polymerization and their aggregation behavior in a selective solvent
Authors: Fu Junwei , Cheng Zhenping , Zhou Nianchen , Zhu Jian , Zhang Wei , Zhu Xiulin
Published: August 2014

Well-defined naphthalene end-capped poly(styrene)-block-poly(Nisopropyl- acrylamide)-block-poly(styrene) (PS-b-PNIPAM-b-PS) amphiphilic triblock copolymers with different molecular weights and block copolymer compositions were successfully prepared via consecutive reversible additionfragmentation chain transfer (RAFT) polymerizations using a novel RAFT reagent, S,S'-bis(1-naphthylmethyl) trithiocarbonate (BNTTC). The aggregation behaviour of the prepared PS-b-PNIPAM-b-PS in water/DMF mixture was studied by transmission electron microscopy (TEM). The effect of the copolymer concentration, PNIPAM block length and the irradiation of UV-light on the sizes and morphologies of micelles were also investigated.
Synthesis and properties of novel polyimides containing 2,6-benzobisoxazole units
Authors: Meng Xiangli , Huang Yudong , Lv Zushun , Yu Hong
Published: August 2014

The diamine monomer, 2,6-bis(p-aminophenyl)-benzo-[1,2-d; 5,4-d’] bisoxazole was successfully synthesized. Three aromatic polyimides (PI) based on 2,6-bis(p-aminophenyl)-benzo-[1,2-d; 5,4-d’] bisoxazole were prepared via a conventional two-stage procedure with a variety of dianhydrides. Their structures and properties were characterized by FTIR, 1H NMR, TG, DSC and XRD. The intermediate poly(amic-acid)s (PAA) had inherent viscosities of 1.18-1.70 dL/g and could be thermally converted into lightly yellow polyimide films. The resulted polyimides showed excellent thermal stability, and the glass transition temperatures (Tg) of all polymers were above 280 oC, and the 5% weight loss temperatures of polymers were about 550 oC in N2. The solubility of these polyimides in various solvents was evaluated. They were all insoluble in conventional polar aprotic solvents.
Modification of cellulose by UV-grafting of an organopolysilazane oligomer
Authors: Serafini P.M. , Bongiovanni R. , Zeno E.
Published: August 2014

The modification of cellulose fibers by grafting specific functions could improve their quality and allow their use for the development of new products. In this work we report about the functionalization of a cellulose fiber network (filters) with organo-polysilazane oligomers by UV-irradiation. Photo-induced grafting, as assessed by contact angle and TGA measurements, was successful: an interesting enhancement of thermal resistance and mechanical properties was obtained. Water repellency was also achieved.
Thermal stability of ammonium salts as compatibilizers in polymer/layered silicate nanocomposites
Authors: Galimberti Maurizio , Martino Marco , Guenzi Monica , Leonardi Gabriella , Citterio Attilio
Published: August 2014

Thermal stability of alkyl and arylalkyl quaternary ammonium cation (onium) in starting chloride salt, in organoclay obtained after exchange with montmorillonite (MMT) and after mixing of the organoclay with isoprene rubber was examined using conventional TGA and by mass spectrometry pyrolysis/GC-MS. Degradation was observed to occur at T ≥ 170 °C for organoclays and the main volatile compounds were identified as tertiary amines, chloroalkanes and alkenes. Mechanisms for their formation are proposed and the role of residual onium chloride and basic centers of layered silicate is discussed.
Synthesis and basic properties of sulfonated polysulfone/phosphotungstic acid (H3O40PW12) composite proton exchange membrane
Authors: Li Weidong , Fei Guoping , Zhao Jiongxin
Published: August 2014

The sulfonated polysulfone/phosphotungstic acid (SPSU/PWA) composite membranes were investigated for proton exchange membranes. The influence of the interactions between sulfonic acid groups and phosphotungstic acid on the properties of composite membranes was studied in detail. The study showed that special interaction has great influence on the membrane properties. Fourier transform infrared (FTIR) spectroscopy of the composite membranes exhibited band shifts showing a possibility of intermolecular hydrogen bonding interaction between SPSU and PWA additives. SPSU/PWA composite membranes were evaluated for thermal stability, ion exchange capacity, water uptake and proton conductivity. Also the extraction of PWA from the composite membranes and their chemical stability were determined. Thermal analysis of the composites showed that it promotes the decomposition temperature of the sulfonic acid groups with increase in PWA weight content. Though the IEC and water uptake decreased with increase in PWA content, the proton conductivity of the composite membranes increased with increase in PWA content. The proton conductivity of the composites with 5 wt.%, 20 wt.% and 30 wt.% PWA is 2.62×10-2, 1.34×10-1 and 1.66×10-1 s·cm-1 at 80oC, respectively.
Preparation of epoxy/urethane graft interpenetrating polymer networks and study of mechanical, thermal and morphological properties
Authors: Ghafghazi Mehdi , Esfandeh Masoud , Morshedian Jalil
Published: August 2014

This paper describes the preparation of Epoxy/Urethane (EP/PU) graft interpenetrating polymer networks (g-IPNs) and investigates the effect of EP/PU weight ratio and urethane's prepolymer molecular weight on the mechanical, morphological and thermal properties of the IPN system. Here, g-IPN was prepared by thorough mixing of an isocyanate-terminated urethane prepolymer with an epoxy resin followed by simultaneous curing of the resins. Polytetra hydrofuranate (PTHF), molecular weights (Mw) 1000, 2000 and 3000 g/gmol, was used to prepare urethane prepolymers. EP/PU weight ratios were 75/25, 50/50, 30/70 and 15/85. Disappearance of epoxide and isocyanate functional groups was followed by Fourier Transform Infrared spectroscopy (FT-IR), showing curing of the resins. Differential Scanning Calorimetry (DSC) was used to investigate the glass transition temperature (Tg) of the IPNs. Thermal Gravimetric Analysis (TGA), Dynamic Mechanical Thermal Analysis (DMTA), tensile measurements and Scanning Electron Microscopy (SEM) were used to study thermal, mechanical and morphological properties of the prepared systems. The best mechanical properties were obtained at EP/PU weight ratio 75/25 which also shows a fine and uniformly dispersed morphology. Moreover, at this ratio, with increasing PTHF Mw in the urethane prepolymer, the mechanical properties were improved whereas a decrease was observed in Tg and thermal degradation temperature of g-IPNs.
Functionalization of polypropylene and compatibilization of polypropylene/nylon 6 blends with copolymers containing α-methyl styrene units
Authors: Liang Shu-jun , Yang Wan-tai
Published: August 2014

In our earlier works, a new and viable strategy for bulk polymerization of methyl methacrylate (MMA) and styrene (St) with copolymers of poly(AMS-co- GMA) (PAG) of α-methyl styrene (AMS) and glycidyl methacrylate (GMA) has been reported. Herein, we report on the achievements of the compatibilization of the blend system of polypropylene (PP) and Nylon 6 (Ny6) and the functionalization of PP with PAG. The graft reactions of PAG onto PP in solution and molten state were investigated respectively, and the functionalized production was confirmed by the FT-IR spectra. Through SEM, the in-situ compatibilization of PP/Ny6 blends with PAG was observed. And the block copolymers of PP-b-PAG-b-Ny6 in the blends were characterized by FT-IR, which confirmed the “compatibilizing effect” of PAG in the blend system.
Graft polymers prepared by catalytic chain transfer polymerization (CCTP) and applied as solvent-borne dispersants for carbon black dispersions of high solid
Authors: Wang Yongqiang , Zeng Guangpeng , Sun Tairong , Hong Xinlin , Ling Jianxiong , Zhang Gaoyong
Published: August 2014

In this article, a series of graft polymer dispersants were conveniently prepared by the grafting through method, among which the macromonomer was synthesized with one-pot through CCTP technology. Rheology and transmission electron microscopy (TEM) were utilized to study the influence of amide content on the carbon black (CB) dispersing ability of these polymers in xylene. When the tertiary amino groups on the backbone were partly quaternized, the apparent viscosity of the obtained CB suspensions decreased remarkably and the flocculation of the CB particles are effectively suppressed. TEM observations showed that the CB particles were well dispersed by the quaternized dispersant. It could be concluded that the graft polymers with a certain amount of quaternized amino groups (20 wt.%) are an efficient dispersants of CB in organic solvent.
Synthesis, characterization and antifungal properties of N,O-(acyl)-N-(trimethyl) chitosan chloride
Authors: Li Rongchun , Guo Zhanyong
Published: August 2014

Three novel water soluble chitosan derivatives: N,O-(acetyl)-N- (trimethyl) chitosan chloride (ATMCS), N,O-(benzoyl)-N-(trimethyl) chitosan chloride (BTMCS), N,O-(chloracetyl)-N-(trimethyl) chitosan chloride (CATMCS) were successfully synthesized. All the derivatives were soluble in water at pH 7. The antifungal properties of the derivatives against two plant fungus Gloeosporium theae-sinensis (G. theae-sinensis) and Phomopsis asparagi (P. asparagi) were studied. The results indicated that the antifungal activities of ATMCS, BTMCS and CATMCS enhanced compared with that of N-(trimethyl) chitosan chloride (TMCS). Against G. theae-sinensis and P. asparagi, BTMCS and CATMCS exhibited much better activities than ATMCS which was may be due to the phenyl and chlorine respectively. Generally speaking, acyl modification of TMCS was effective.
Thermal stability and mechanical properties of modified starch/NR composite
Authors: Wang Zhi-Fen , Li Si-Dong , Fu Xin , Lin Hua , She Xiao-Dong , Huang Jie
Published: August 2014

The starch/natural rubber composite was prepared by blending the modified starch by esterification with natural rubber latex. The modified starch particles are homogenously distributed throughout the natural rubber (NR) matrix. In comparison with the host NR, the thermal stability of composite is significantly improved. The thermal degradation temperatures (T) and reaction activation energy (E) of composite are higher than those of the pure NR. The hardness, stress at 500%, tensile strength, permanent deformation and tear strength of composite increase linearly with the increment of dosage of modified starch.
Characterization of hydroxylated hyperbranched polyesters of fourth and fifth generation
Authors: Murillo Edwin A. , Vallejo Pedro P. , López Betty L.
Published: August 2014

Hydroxylated hyperbranched polyester (HBPs) of fourth and fifth generation were obtained by three methods; one step (HBP4, HBP5), step by step (HBP4P, HBP5P) and combinations of one step and step by step (HBP1-4, HBP1- 5). The HBPs were synthesized in bulk from 2,2-bis(hydroxymethyl)propionic acid (DMPA) and pentaerythritol (PE) using acid catalysis (p-toluenesulfonic acid) and characterized by infrared analysis, 1H and 13C nuclear magnetic resonance, gel permeation chromatography, vapor pressure osmometry, electro spray ionizationmass spectrometry, dynamic light scattering, refractive index, thermogravimetric and differential scanning calorimetric analysis. The refractive index of HBPs were low, the infrared and nuclear magnetic resonance analysis showed evidence of the occurrence of reaction between from 2,2-bis(hydroxymethyl) propionic acid (DMPA) and pentaerythritol (PE). The molar mass values of the HBPs determined by gel permeation chromatography were different to vapor pressure osmometry measurements due to small hydrodynamic volume of the HBPs. The mass spectrometry analysis showed different acyclic and cyclic units in the HBPs. The distributions of HBPs studied by dynamic light scattering were monomodal in number and volume and bimodal in intensity. The thermal stability of the fifth generation HBPs was higher than that the fourth generation. All HBPs presented amorphous behavior
Isothermal crystallization of high density polyethylene with monomodal and bimodal molar mass distribution
Authors: Tang Yujing , Jiang Zhiyong , Rieger Jens , Enderle Hans-Friedrich , Lilge Dieter , Men Yongfeng
Published: August 2014

The isothermal crystallization behavior of two different high density polyethylene grades with monomodal and bimodal molar mass distribution was investigated by means of differential scanning calorimetry. The results indicate that extensive cocrystallization between linear short chains and long chains with short branches in bimodal polyethylene grade occurred. In contrast, polymer chains of different lengths in monomodal polyethylene exhibit different tendency to crystallize. This finding was explained qualitatively based on a general discussion of the effect of molar mass and branch content/length on crystallization tendency of polymeric chains.
Dependence of comonomer effect and hydrogen effect on internal donor in ethylene/1-hexene copolymerizations with MgCl2-supported catalysts
Authors: Zhang Letian , Fan Lina , Fan Zhiqiang , Fu Zhisheng
Published: August 2014

Ethylene homopolymerization and copolymerizations with 1-hexene by three types of MgCl2-supported catalysts were compared. Cat-1 contains no internal electron donor (ID), Cat-2 contains phthalic anhydride (PA) as ID, and Cat- 3 contains anisole as ID. The influences of two kinds of ID on comonomer effect, the role of hydrogen, polymerization kinetics in ethylene/1-hexene copolymerization were investigated. The addition of ID improves the catalysts activities in ethylene polymerization. In comparison with ethylene homopolymerization, these ethylene/1-hexene copolymerization systems all showed strong comonomer effects. However, internal donor, especially anisole, weakens the extent of comonomer activity enhancement. When the concentration of 1-hexene is 0.6 mol/L, catalysts activities increase remarkably with adding a small amount of hydrogen. But, the addition of ID reduces the sensitivity of catalyst activity to hydrogen. The introduction of anisole increases the homo-polymerization rate rapidly at the initial stage, but makes it decay earlier. In ethylene/1-hexene copolymerization with hydrogen, the addition of phthalic anhydride as ID can stabilize the polymerization rate, but anisole accelerates the decaying trends. The results are discussed based on a kinetic mechanistic model of the ID effect on ethylene copolymerization.
Epoxy-based nanocomposites with amine modified single walled carbon nanotubes
Authors: Petrea Celina-Maria , Andronescu Corina , Pandele Andreea Madalina , Garea Sorina Alexandra , Iovu Horia
Published: August 2014

Carboxylated Single Walled Carbon Nanotubes (SWNT-COOH) were functionalized using different types of amines as modifier agents to improve the compatibility with the epoxy matrix. Covalent attachment was proved by XPS and Raman spectroscopy. TGA showed that only long chain modifier agents improved the thermal stability of modified SWNTs. Epoxy-based composites were synthesized using diglycidyl ether of bisphenol A (DGEBA) as polymer matrix and modified SWNTs as reinforcing agent.
External potential dynamics simulation of the compatibility of T-shaped graft copolymer compatibilizing two immiscible homopolymers
Authors: Li Wei , Jiang Wei
Published: August 2014

The compatibilizing effect of T-shaped graft copolymers between two incompatible homopolymers A and B was studied by using the external potential dynamics (EPD) method based on dynamic self-consistent field theory. We specifically focus on the role of the concentration and the junction position of the graft copolymer on the compatibility. The blend containing compatibilizers exhibits slow dynamics during the phase separation. We observed that the compatiblizers are particularly efficient when the graft point is close to the free end of the backbone chain.
Preparation of a new polypropylene/clay nanocomposites via in situ polymerization
Authors: Naderi Ghasem , Nekoomanesh Mehdi , Mehtarani Reza. , Eslami Hasan.
Published: August 2014

Novel polypropylene/clay nanocomposites were prepared by in situ polymerization method with TiCl4/MgCl2/organoclay/internal donor- AlEt3 catalyst. The organo clay used is commercial Closite 15A that is an ammonium saltmodified montmorillonite (AMMT). For preparation of the catalyst, MgCl2 was deposited into the swollen AMMT layers and then TiCl4 and internal donor were loaded on the layer surfaces of AMMT. X-ray diffraction (XRD), transmission electron microscopy (TEM) and rheological measurements were used for characterization of the nanocomposites. The Linear and nonlinear melt-state viscoelastic properties of the polymer matrix and its nanocomposite are also investigated. In the presence of the clay lamellae, a pronounced increase in the low frequency moduli is observed. Transient rheological data reveal a stress overshoot for nanocomposite where there is no significant overshoot for polymer matrix. This stress overshoot can be attributed to the deformation and orientation of the special structure of clay platelets in polymer melts. Finally, experimental data are compared with the predictions of a mesoscopic rheological model.
Terpolymers of N-vinylpyrrolidinone and 1-vinylimidazole as new supports for palladium nanocluster catalysts
Authors: Strzelec Krzysztof , Wąsikowska Karolina , Cypryk Marek , Pospiech Piotr
Published: August 2014

Two terpolymers of styrene, divinylbenzene, and 1-vinylimidazole (S/DVB/VI) or N-vinylpyrrolidinone (S/DVB/NVP) were prepared by radical polymerization. Palladium nanoparticle catalyst has been “heterogenized” by anchoring to these polymers the [PdCl2(PhCN)2] complex via ligand exchange reaction. The formation of coordination bond between S/DVB/VI, S/DVB/NVP terpolymers and Pd2+ ions was studied using infrared and XPS. Immobilized palladium complex was reduced during hydrogenation reaction or by reaction with sodium borohydride. Characterization of polymer supports and palladium catalysts has involved the measurements of the structural parameters in the dry state by the nitrogen BET adsorption, X-ray photoelectron spectroscopy (XPS), AAS spectroscopy and time-of-flight secondary ion mass spectrometry (TOF-SIMS). Both the catalytic systems were found efficient in the hydrogenation of cinnamaldehyde. The stability and a good recycling efficiency of these catalysts make them useful for prolonged use. The factors influencing selectivity of supported catalysts were discussed. The results offer the possibility of using these terpolymers for the immobilization of metal complex catalysts for hydrogenation and other catalytic reactions.
The anomalous behavior of physical-chemical parameters during polymerization of organic-inorganic polymer systems based on reactive oligomers
Authors: Iurzhenko Maksym , Mamunya Yevgen , Seytre Gerard , Boiteux Gisele , Lebedev Eugene
Published: August 2014

Dependencies of physical-chemical characteristics on structure development during polymerization of organic-inorganic systems (OISs) have been investigated. The non-monotonic behavior of the physical parameters has been found. This effect was explained by complicated structure of OISs, which consists of two interpenetrating hybrid organic-inorganic networks, which are characterized by different rate of the structure formation.
Improving hydrophilicity and protein resistance of silicone hydrogel by plasma induced graft polymerization of 2- methacryloyloxyethyl phosphorylcholine
Authors: Sun Fuqian , Li Xinsong , Xu Jinku , Cao Peiting , Xiao Lijian
Published: August 2014

Surface properties of silicone hydrogels used as soft contact lenses play an important role in biocompatibility, conformability and deposition of protein. In this report, the surface hydrophilicity and protein deposition resistance of silicone hydrogel were modified using an atmospheric pressure glow discharge plasma (APGDP) induced graft polymerization of 2-methacryloyloxyethyl phosphoryl choline (MPC). Silicone hydrogel was treated with plasma and exposed to air to form oxide and hydroperoxides at the surface, which initiated surface graft polymerization of MPC. Elemental composition and structure at the surface of silicone hydrogel were characterized through ATR-FTIR and XPS. The data of ATR-FTIR and XPS analyses revealed that MPC was grafted onto the surface of silicone hydrogel. Contact angle measurement was used to evaluate the hydrophilic property of the silicone hydrogel. The MPC grafted silicone hydrogel has the contact angle about 55° when MPC solution with the concentration 10 wt% is applied for graft polymerization. The result showed that graft polymerzation of MPC improved the hydrophilicity of silicone hydrogel efficiently. Bovine serum albumin (BSA) was used as a model to investigate protein deposition resistance of the modified silicone hydrogel. The data obtained by bicinchoninic acid assay revealed that the grafted silicone hydrogels had a significant enhancement of protein resistance.
Molecular dynamics study on the reason of fluorescence quenching of a pyrene-functionalized fluorescent film
Authors: Kong Hongyan , Liu Jing , Wang Liqiang
Published: August 2014

Experimentally, the fluorescent intensity of the pyrene-functionalized fluorescent film is reduced by introducing nitrobenzene. In order to fulfill the functional reason of this quenching effect, a molecular dynamics simulation is adopted in this paper. The simulation finds that the structural modification of the pyrene molecules in the film is the main reason for the quenching effects. Result reveals that, in the vacuum environment, the distance between a pair of pyrene ring centers distributes from about 4 Å to 10 Å, and a large number of distances populate at 5.3 Å, which is a suitable distance for excimer emission. The introduction of nitrobenzene results in a decrease of the population of pyrene molecules within that distance, indicating a decrease of excimer emission of the film. In addition, the pyrene molecule rings in the film prone to adopt quasi-coplanar structure in the vacuum, but less likely arrange into a coplanar structure when nitrobenzene is introduced. Study clearly indicates that the structural changes are all caused by the insertion of the incoming nitrobenzene molecules into the previously coplanar pyrene rings. Finally, length and orientation of chain are also analyzed. All the expectations from the simulation studies are basically consistent with the experimental observations.
Preparation and properties of waterborne siloxane-containing polyurethane for moisture permeable textile coating
Authors: Lei Haibo , Luo Yunjun , Ge Zhen , Li Xiaomeng , Wang Shengpeng
Published: August 2014

Waterborne siloxane-containing polyurethanes (WSPU) were prepared by polyaddition reaction using poly(tetramethylene oxide)glycol (PTMG), polyethylene glycol (PEG), and α,ω-aminopropyl polydimethylsiloxane (APDMS) as mixing soft segments; 2,2-di(hydroxymethyl)propionic acid, as a hydrophilic chain extender; 1,4-butanediol and isophorone diisocyanate as hard segment; triethylamine as a neutralization agent. The thermal properties of WSPU films were analyzed by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and thermal gravimetric analysis (TGA). The mechanical properties of WSPU film were also investigated. Water vapor permeability (WVP) was examined according to GB_T 12704-1991. The DSC and DMA results indicated that there is a micro-phase separation in the WSPU film. The incorporation of APDMS into PU made the thermal stability of hard segment worse while that of soft segment better. The elasticity of WSPU was improved when the APDMS content was not more than 10%, the vapor permeability of coated fabric increased firstly and then decreased as the APDMS content increased, which was resulted from the hydrophilicity change and microstructure change of membrane. When 10% APDMS was incorporated into the WSPU, the WVP of coated fabric was 2130.15 g/(m2·24h), equal to one coated with a widely used solvent-based PU sample (UECCOAT), and the water resistance (WR) reached 30.0 KPa.
Preparation of PAA/PEO blend nanofibers via electrospinning process
Authors: Shami Zahed , Sharifi-Sanjani Naser
Published: August 2014

The novel poly(acrylic acid)/poly(ethylene oxide) (PAA/PEO) blend nanofibers at 100/0, 80/20, 50/50, 20/80 and 0/100 weight ratios were obtained via electrospinning process. Intermolecular interactions and compatibility of blend fibers were studied by Fourier transform infrared (FT-IR) and differential scanning calorimetry (DSC). It was found that the free-hydroxyl groups, the bonded hydrogen hydroxyl groups and the carbonyl groups absorption bands in the electrospun PAA/PEO fibers shifted with the increase in PEO percentage in the blend. DSC measurements showed the melting point, the glass transition temperature, the melting enthalpy and the crystallinity percentage of pure polymer nanofibers were different compared with blend nanofibers. The results suggested that intermolecular interactions occurred in the electrospun PAA/PEO nanofibers. These interactions made PAA/PEO blends miscible at above-mentioned weight ratios. Additionally, the morphology and the average fiber diameter were investigated using scanning electron microscope (SEM) analysis, which indicated beadless fibers with diameter range of 110 to 280 nm. It was observed that the uniform fibers with the smaller average diameter were obtained in PAA/PEO blends containing PAA dominant content. Finally, the SEM results suggested that the formation of pure PAA nanofibers with concentration of 5 Wt. % would not occur. Whereas, in the same concentration, pure PEO and PAA/PEO blend nanofibers with no bead defects were obtained.
Effect of layered silicates on rheological and mechanical properties and thermal stability of high-molar mass polydimethylsiloxane matrix
Authors: Rabova Veronika , Hron Petr
Published: August 2014

The effect of surface modified fillers based on montmorillonite on rheological and mechanical properties and thermal stability of high-molar mass polydimethylsiloxane matrix was evaluated. Silicone rubber/clay composites were prepared via homogenisation on open two roll-mill followed by torque measurement at two different temperatures. At 30 °C and 100 °C the torque did not extremely differ excepting the mixtures containing Cloisite 15A where it achieved the maximum at 3 phr montmorillonite content, but the tensile strength reached the similar values in all mixtures. Thermogravimetric analysis was utilized to find out the differences in weight decay of composites in silicone rubber/montmorillonite mixtures and in unfilled silicone rubber. Synergism of fillers was also studied and led to tensile strength increase.
Precipitated calcium carbonate as carrier particles of ‘dry liquids’ for post-processing crosslinking reactions
Authors: Vogel Roland , Vučak Marijan , Nover Christoph , Peitzsch Lutz
Published: August 2014

Precipitated calcium carbonates (PCC) of different particle morphologies were used as appropriate carrier particles for post-processing crosslinking reactions. Optimum particle morphology and size were estimated for preparation of dry liquids (DLs). The DLs were tested in three different typically crosslinking reactions of polymers.
Reentrant swelling behavior of poly(4-vinyl phenol) gel in aqueous organic solvent mixtures
Authors: Sakurai Michiko , Satoh Mitsuru
Published: August 2014

Swelling behaviours of poly(4-vinyl phenol) (P4VPh) hydrogel in various kinds of mixed solvents (methanol, ethanol, 2-propyl alcohol, t-butyl alcohol, acetone, acetonitrile, dioxane, THF and DMSO) have been investigated. With increasing the organic solvent content, the gel first significantly deswelled and then reswelled via lowest swelling points (10-60 vol.% depending the solvent species), and finally showed a second deswelling in the highest content region (typically ≧ 80 vol.%). The rather unique swelling-deswelling sequence was not reproduced when the solvent content was decreased; namely, the backward swelling curves obtained with increasing water composition in the mixed solvents first followed the forward one until the lowest swelling points, then, however, continued the deswelling trend without recovering the initial swelling state in water. This remarkable hysteresis as well as the reentrant swelling with the extra second deswelling has been interpreted in terms of the intermolecular interactions, i.e., hydrogen bonding between the phenol OH groups and the π- π stacking of the phenol rings, by referring to the corresponding results of poly(vinyl alcohol) (PVA) gel system.
Mechanical characterization of rigid π-conjugated polymer on a nanometer scale through nanoindentation
Authors: Liang Bo , Zhang Zhen-lin , Wu Lai-Lei , Zhao Li-cheng , Zhang Shuai , Wang Peng , Zhang Hai-Quan
Published: August 2014

The evaluating mechanical performance of Π-conjugated Polymer films has important significance for application in the micro electronic devices. In this work, authors studied micro mechanical performance of Π-conjugated polymer, poly[2-methoxy-5-(2’-ethyl hexyloxy)-phenylene vinylene] used nanoindentation technique at room temperature and discussed effect of experimental parameter on the effective elastic modulus and hardness of MEH-PPV film. The experimental result indicates the estimating effective elastic modulus and hardness using O & P formula are correlative with load, holding time, and loading rate. Detail analysis in combination with related literature indicated the effective elastic modulus and hardness of MEH-PPV film are approximately 6.79±0.12GP, 0.37±0.16 GP, respectively. Furthermore, increasing the loading rate could decrease the effective elastic modulus and hardness, which was opposite comparing with typical polymer materials (poly (methyl methacrylate) (PMMA) etc ).
Electroactive perovskite lead zirconate particles embedded in an acrylic elastomer
Authors: Tangboriboon Nuchnapa , Sirivat Anuvat , Kunanuruksapong Ruksapong , Wongkasemjit Sujitra
Published: August 2014

Lead zirconate was synthesized via the sol-gel process and calcined at 300°C for 1 h to obtain a Perovskite structure of an orthorhombic form. SEM micrographs indicate that the lead zirconate particles are moderately dispersed in a solid acrylic rubber, AR71. Without an electric field, the particles merely act as a dielectric filler that can absorb and store additional stress. Under electrical field, particle-induced dipole moments are generated, leading to the interparticle interactions, thus creating a substantial increase in the storage modulus. At the small volume fraction of lead zirconate particles of 0.02 embedded in the elastomer matrix, the electrical conductivity increases dramatically by two orders of magnitude. At the volume fraction of merely 0.0002, the storage modulus, or the composite rigidity, increases by a factor of two as the electric field strength is varied from 0 to 2 kV/mm.
Characterization of molecular orientation under tensile deformation by near infrared spectroscopy
Authors: Mizushima Masami , Kawamura Takanobu , Takahashi Kenji , Nitta Koh-hei
Published: August 2014

We present a novel method for characterizing orientation behavior of typical polyethylene (PE) materials such as HDPE, LLDPE, and LDPE. The chain orientation to the stretching direction was examined under uniaxial deformation by near infrared spectroscopy. Then we obtained directly the orientation function of PE chain axis (c-axis) from the CH stretching vibration of NIR spectra as a function of extension time or strain. We compared the present method with the conventional infrared IR method where the orientation function of PE c-axis (chain-axis) has been indirectly obtained from the b-and a-axis’s assuming the orthogonal crystal form by using the CH2 rocking vibrations in IR spectra
Effect of ball milling on lignin polyesterification with ε-caprolactone
Authors: Kandula Maja , Schwenke Tasja , Friebel Stefan , Salthammer Tunga
Published: August 2014

Industrially produced lignins are by-products of the pulp and paper industry and depending on the source and pulping technology they have deviating functional groups, solubility behavior and reactivity. In the present paper, kraft lignin was pretreated by mechanical milling and polyesterified with ε-caprolactone to create hydroxyl groups that are more easily available for further reactions. The products obtained were analysed by size exclusion chromatography (SEC), differential scanning calorimetry (DSC) and functional group determination. The analytical data are presented as a function of reaction time, crosslinking reactions and the amount of ε-caprolactone input.
Fingierte Lernersprachen
Authors: Fobbe Eilika
Published: August 2014

One of the most significant tasks in forensic analysis of written discourse is to examine whether a text is genuine or in some way falsified. In order to deceive the addressee of a blackmail letter, authors often try to disguise their mother tongue by introducing different kinds of artificial errors. The paper firstly deals with the difficulties one has in judging the authenticity of an error, the cognitive conditions of deliberate error production, and its intended purposes. This is followed by a presentation of the results of a study carried out with 98 German native speakers who were asked to write a blackmail letter simulating a non-native speaker identity. The focus of the corpus analysis lies in the description and interpretation of the morphological and syntactical errors produced by the participants. It shows that many participants singled out identical grammatical categories, and produced similar patterns of errors, resembling the defective structures of German foreigner talk. The results from this study suggest that deliberate error production is affected by the cognitive load caused by the asignment, and is automated to a higher degree, and that its patterns are noticeably shaped by the grammatical structures of the mother tongue.
Human Factors and Health Information Technology: Current Challenges and Future Directions
Authors: Kannampallil T. G. , Patel V. L.
Published: August 2014

Objectives: Recent federal mandates and incentives have spurred the rapid growth, development and adoption of health information technology (HIT). While providing significant benefits for better data integration, organization, and availability, recent reports have raised questions regarding their potential to cause medication errors, decreased clinician performance, and lowered efficiency. The goal of this survey article is to (a) examine the theoretical and foundational models of human factors and ergonomics (HFE) that are being advocated for achieving patient safety and quality, and their use in the evaluation of health-care systems; (b) and the potential for macroergonomic HFE approaches within the context of current research in biomedical informatics.

Methods: We reviewed literature (2007-2013) on the use of HFE approaches in healthcare settings, from databases such as Pubmed, CINAHL, and Cochran.

Results: Based on the review, we discuss the systems-oriented models, their use in the evaluation of HIT, and examples of their use in the evaluation of EHR systems, clinical workflow processes, and medication errors. We also discuss the opportunities for better integrating HFE methods within biomedical informatics research and its potential advantages.

Conclusions: The use of HFE methods is still in its infancy - better integration of HFE within the design lifecycle, and quality improvement efforts can further the ability of informatics researchers to address the key concerns regarding the complexity in clinical settings and develop HIT solutions that are designed within the social fabric of the considered setting.
Comparison of sand and membrane filtration as non-chemical pre-treatment strategies for pesticide removal with nanofiltration/low pressure reverse osmosis membranes
Authors: Kowalski Krzysztof P. , Madsen Henrik T. , Søgaard Erik G.
Published: August 2014

Pilot plant investigations of sand and membrane filtration (microfiltration (MF)/ultrafiltration (UF)/nanofiltration (NF)/low pressure reverse osmosis (LPRO)) have been performed to treat groundwater polluted with pesticides. The results show that simple treatment, with use of aeration and sand filtration or MF/UF membranes, does not remove pesticides. However, by reducing the content of key foulants, the techniques can be used as a pre-treatment for nanofiltration and low pressure reverse osmosis that has proved to be capable of removing pesticides. It was found that a lower fouling potential could be obtained by using the membranes, but that sand filter was better at removing manganese and dissolved organic matter. The results indicate that combining aeration, sand filtration and membrane techniques might be a good option for pesticide removal without any addition of chemicals and minimized membrane maintenance.
Pretreatment of furfural industrial wastewater by Fenton, electro-Fenton and Fe(II)-activated peroxydisulfate processes: a comparative study
Authors: Yang C. W. , Wang D. , Tang Q.
Published: August 2014

The Fenton, electro-Fenton and Fe(II)-activated peroxydisulfate (PDS) processes have been applied for the treatment of actual furfural industrial wastewater in this paper. Through the comparative study of the three processes, a suitable pretreatment technology for actual furfural wastewater treatment was obtained, and the mechanism and dynamics process of this technology is discussed. The experimental results show that Fenton technology has a good and stable effect without adjusting pH of furfural wastewater. At optimal conditions, which were 40 mmol/L H2O2 initial concentration and 10 mmol/L Fe2+ initial concentration, the chemical oxygen demand (COD) removal rate can reach 81.2% after 90 min reaction at 80 °C temperature. The PDS process also has a good performance. The COD removal rate could attain 80.3% when Na2S2O8 initial concentration was 4.2 mmol/L, Fe2+ initial concentration was 0.1 mol/L, the temperature remained at 70 °C, and pH value remained at 2.0. The electro-Fenton process was not competent to deal with the high-temperature furfural industrial wastewater and only 10.2% COD was degraded at 80 °C temperature in the optimal conditions (2.25 mA/cm2 current density, 4 mg/L Na2SO4, 0.3 m3/h aeration rate). For the Fenton, electro-Fenton and PDS processes in pretreatment of furfural wastewater, their kinetic processes follow the pseudo first order kinetics law. The pretreatment pathways of furfural wastewater degradation are also investigated in this study. The results show that furfural and furan formic acid in furfural wastewater were preferentially degraded by Fenton technology. Furfural can be degraded into low-toxicity or nontoxic compounds by Fenton pretreatment technology, which could make furfural wastewater harmless and even reusable.
Effect of pH on phosphorus, copper, and zinc elution from swine wastewater activated sludge
Authors: Waki Miyoko , Yasuda Tomoko , Fukumoto Yasuyuki , Suzuki Kazuyoshi
Published: August 2014

With the goal of reducing the amounts of phosphorus (P), copper (Cu), and zinc (Zn) discharged from swine wastewater activated sludge treatment facilities, we studied the elution of these elements from activated sludge at various pH values. Sludge samples with neutral pH collected from three farms were incubated at pH values ranging from 3 to 10. The soluble concentrations of these elements changed dramatically with pH and were highest at pH 3. We assumed that P present in the sludge under neutral and alkaline conditions was in insoluble form bound up with magnesium (Mg) and calcium (Ca), because Ca and Mg also eluted from the sludge at low pH. To clarify forms of Zn and Cu in the sludge, we performed a sequential extraction analysis. Zinc in adsorbed, organically bound, and sulfide fractions made up a large proportion of the total Zn. Copper in organically bound, carbonate, and sulfide fractions made up a large proportion of the total Cu. The soluble P concentrations were lowest at pH 9 or 10 (11–36 mg/L), the soluble Zn concentrations were lowest at pH 8 or 9 (0.07–0.15 mg/L), and the soluble Cu concentrations were lowest at pH 6–9 (0.2 mg/L, the detection limit).
Long-term effects of ACE inhibitor on vascular remodelling
Authors: Tuleta Izabela , Bauriedel Gerhard , Krämer Stefan , Nickenig Georg , Skowasch Dirk
Published: August 2014

The long-term pathomorphological changes of the injured vessels under angiotensin-converting-enzyme (ACE) inhibitor are still not known. Therefore, we assessed the alternations of vascular architecture after three-month therapy with ACE inhibitor and identified new target cells for this medication. Carotid arteries of spontaneously hypertensive rats underwent balloon angioplasty. 14 days prior intervention, half of the animals was treated with ACE inhibitor. After three months of vascular trauma, the injured vessels were explored by histomorphology and immunohistochemistry for angiotensin-II receptor (AT1R), dendritic and HSP47+ cells. The neointimal growth decreased significantly only up to 28 days under ACE inhibitor. In contrast, the reductive effect of ACE inhibitor on media area persisted up to three months after intervention. A significant fraction of early neointimal cells was of a dendritic cell type. The relevant portion of these cells showed an expression of AT1R and HSP47. AT1R was present in 70% and HSP47 in 18% of all early neointimal cells in both groups. ACE inhibitor may at least temporarily diminish remodelling processes in injured vessels. The detection of AT1R on dendritic cells identifies these cells as important targets for therapeutic strategies involving modulation of the renin-angiotensin system.