bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of electrorheological properties of kaolin suspensions under DC fields
Authors: Yilmaz Hasim , Yilmaz Ummihan
Published: December 2006

In this study, the electrorheological (ER) behavior of suspensions prepared from d50 = 7 μm kaolin particulate, dispersed in insulating silicone oil (SO) medium, was investigated. ER activity of all the suspensions was observed to increase with increasing electric field strength (E), concentration (c), and decreasing shear rate ($ {\dot{\gamma}} $). Shear stress ($ {\dot{\gamma}} $) of kaolin suspensions increased linearly with increasing concentrations of the particles and with the applied electric field strength. The viscosity (η) of all suspensions was decreased sharply with increasing shear rate and showing a typical shear thinning non‐Newtonian viscoelastic behavior. It was observed that kaolin/silicone oil system studied in the present work was sensitive to high temperature. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3798–3802, 2007
Synthesis of N‐aryl azetidine‐2,4‐diones and polymalonamides prepared from selective ring‐opening reactions
Authors: Dai Shenghong A. , Juang Tzong‐Yuan , Chen Chih‐Ping , Chang Hsin‐Yu , Kuo Wen‐Jang , Su Wen‐Chiung , Jeng Ru‐Jong
Published: December 2006

Improved high‐yield synthesis of N‐aryl azetidine‐2,4‐dione has been achieved. The azetidine‐2,4‐dione undergoes ring‐opening reactions with aliphatic primary amines to form malonamide linkages. More importantly, this compound exhibits a high reactivity toward primary aliphatic amine group over alcohols or secondary amines. This selective end‐group functionalization is useful for preparing useful polymer intermediates. In this study polymalonamides were synthesized by fast addition reaction of aliphatic diamine and azetidine‐2,4‐dione. In the meantime, further application for structure‐controlled reaction also has been demonstrated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3591–3599, 2007
Miscibility and physical properties of conducting poly(urea‐urethane) thermoplastic elastomers
Authors: Liu Jia‐Yi , Yang Chao‐Chen , Wang Yen‐Zen
Published: December 2006

A series of amine‐terminated polyaniline oligomer (OPA)‐based conducting poly(urea‐urethane) thermoplastic elastomers (PUUs) was synthesized by two‐stage solution polymerization and characterized by FTIR. Various percentages of OPA were introduced into PUUs as chain extenders to form hard segments of PUUs with urea‐linkages. Spectroscopic and differential scanning calorimetry, as well as dynamic mechanical analysis, were conducted to elucidate the interaction and degree of miscibility between hard and soft segments, which were related to the stress–strain properties of PUUs. The hydrogen bonding index (HBI) measured by FTIR was employed to show the degree of interchain hydrogen bonding. Copolymer films with higher OPA content exhibit higher HBI and the degree of miscibility is significantly improved. The resultant conducting copolymers have higher tensile strength, higher Young's modulus, and lower elongation at break, because of the long rigid structure of OPA and the increase in the number of hydrogen bonds among the copolymers blocks. Incorporating OPA in PUUs increases the mass of the residue at temperatures over 600°C, according to thermogravimetric analysis. The conductivity of PUUs is found to range from 0.83 S/cm for neat OPA to 6.11 × 10−5 S/cm for PUUs. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3803–3810, 2007
Viscoelastic properties of crosslinked LLDPE films biaxially oriented at temperatures below melting point
Authors: Bobovitch A. L. , Unigovski Y. , Gutman E. M. , Kolmakov E. , Vyazovkin S.
Published: December 2006

Creep and stress‐relaxation of linear low‐density polyethylene (LLDPE) crosslinked with β‐irradiation was studied as a function of irradiation dose. It was shown that both storage modulus and α‐relaxation are influenced by irradiation. An influence of relatively low gel content on stress relaxation was detected. However, the creep results showed an increase of the creep strain when the polymer is irradiated with a dose below 4 Megarad (MR) in comparison with a nonirradiated film. This increase corresponded to the disorientation in the amorphous phase, which takes place as a result of the film heating during irradiation. This disorientation was demonstrated by differential scanning calorimetry (DSC) and X‐ray analysis. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 103: 3718–3723, 2007
Synthesis and properties of hydrogenated natural rubber
Authors: Inoue Shin‐ichi , Nishio Tomohiro
Published: December 2006

A series of hydrogenated natural rubbers, HNRs, were prepared by homogenous hydrogenation using H2 gas with a rhodium catalyst (chlorotris(triphenylphosphine)rhodium) in toluene. The HNRs were linear polymers with molecular weights greater than 800,000. These rubbers were vulcanized using sulfur and peroxide compounds. Vulcanized 100% HNR has a low glass transition temperature (Tg = −43°C) and excellent abrasion resistance, and is resistant to oxidation and ozonolysis ageing. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3957–3963, 2007
Comparison of two approaches to grafting hydrophilic polymer chains onto polysulfone films
Authors: Tian Meng , Zhong Rui , Sun Shudong , Zhao Changsheng , Huang Xiaohua , Yue Yilun
Published: December 2006

To reduce the surface protein adsorption of polysulfone (PSf) film, we improved the hydrophilicity of this film by photochemical grafting of methoxypoly (ethylene glycol) (MPEG) derivatives on its surface. Grafting was achieved with both the simultaneous method and the sequential method. Surface analysis of the grafted film by X‐ray photoelectron spectroscopy (XPS) revealed that the PEG chains had successfully grafted onto the surface of the film. The grafting efficiencies by simultaneous and sequential methods were 20.8% and 10.2%, respectively. With an atomic force microscope (AFM), the surface topography of PEG‐grafted films by these two methods was compared. Static water contact angle measurement indicated that the surface hydrophilicity of the film had been improved. Protein adsorption measurement showed that the surface protein adsorption of the modified film was significantly reduced compared with that of the unmodified PSf film. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3818–3826, 2007
Polystyrene nanocomposite materials by in situ polymerization into montmorillonite–vinyl monomer interlayers
Authors: Akelah Ahmed , Rehab Ahmed , Agag Tarek , Betiha Mohamed
Published: December 2006

A different series of new polystyrene–clay nanocomposites have been prepared by grafting polymerization of styrene with vinyl‐montmorillonite (MMT) clay. The synthesis was achieved through two steps. The first step is the modification of clay with the vinyl monomers, such as N,N‐dimethyl‐n‐octadecyl‐4‐vinylbenzyl‐ammonium chloride, n‐octadecyl‐4‐vinylbenzyl‐ammonium chloride, triphenyl‐4‐vinylbenzyl‐phosphonium chloride, and tri‐n‐butyl‐4‐vinylbenzyl‐phosphonium chloride. The second step is the polymerization of styrene with different ratios of vinyl‐MMT clay. The materials produced were characterized by different physical and chemical methods: (1) IR spectra, confirming the intercalation of the vinyl‐cation within the clay interlayers; (2) thermogravimetric analysis (TGA), showing higher thermal stability for PS–nanocomposites than polystyrene (PS) and higher thermal stability of nanocomposites with of phosphonium moieties than nanocomposites with ammonium moieties; (3) swelling measurements in different organic solvents, showing that the swelling degree in hydrophobic solvents increases as the clay ratio decreases; (4) X‐ray diffraction (XRD), illustrating that the nanocomposites were exfoliated at up to a 25 wt % of organoclay content; and (5) scanning electron microscopy (SEM), showing a complete dispersion of PS into clay galleries. Also, transmission electron microscopy (TEM) showed nanosize spherical particles of ∼ 150–400 nm appearing in the images. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3739–3750, 2007
Synthesis and characterization of styrene‐butyl acrylate polymers, varying feed composition in a semicontinuous emulsion process
Authors: Jasso‐Gastinel Carlos F. , López‐Ureta Luz C. , González‐Ortiz Luis J. , Reyes‐González Ignacio , López‐Dellamary T. Fernando A. , Manero‐Brito Octavio
Published: December 2006

Two‐stage polymerization has been used to improve properties of two‐component polymers. In this work, a semicontinuous emulsion process varying feed composition along the reaction is used to produce copolymer chains of different composition as conversion proceeds. Polymer composition and evidence of branching were determined by 1H‐NMR. Polymer molecular weight values determined by GPC are beyond the range where mechanical properties depend on molecular weight. Mechanodynamic properties show a copolymer type behavior with a synergistic effect around the 50/50 styrene/butyl acrylate composition ratio. For such composition, mechanical performance superiority of variable composition copolymer with respect to two‐stage polymer was confirmed with stress–strain tests carried out at several temperatures. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3964–3971, 2007
Mechanical and thermal properties of polypropylene/sugarcane Bagasse composites
Authors: Ramaraj B.
Published: December 2006

To determine the possibility of using sugarcane bagasse (SCB) waste as reinforcing filler in the thermoplastic polymer matrix, SCB‐reinforced polypropylene (PP) composites were prepared. The PP and SCB composites were prepared by the extrusion of PP resin with 5, 10, 15, and 20 wt % of SCB filler in a corotating twin screw extruder. The extruded strands were cut into pellets and injection molded to make test specimens. These specimens were tested for physicomechanical properties such as tensile, flexural, Izod, and Charpy impact strengths, density, water absorption, and thermal characteristics, namely, heat deflection temperature (HDT), melt flow index, and thermogravimetric analysis. It was found that the flexural strength increased from 23.66 to 26.84 MPa, Izod impact strength increased from 10.499 to 13.23 Kg cm/cm, Charpy impact strength increased from 10.096 to 13.98 Kg cm/cm, and HDT increased from 45.5 to 66.5°C, with increase in filler loading from 5 to 20% in the PP matrix. However, the tensile strength and elongation decreased from 32.22 to 27.21 MPa and 164.4 to 11.20% respectively. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3827–3832, 2007
New synthesis methods for polypropylene‐co‐ethylene‐propylene rubber
Authors: Thanyaprueksanon Satit , Thongyai Supakanok , Praserthdam Piyasan
Published: December 2006

In this research, the reinforcement of polypropylene (PP) was studied using a new method that is more practical for synthesizing polypropylene‐block‐poly(ethylene‐propylene) copolymer (PP‐co‐EP), which can be used as a rubber toughening agent. This copolymer (PP‐co‐EP) could be synthesized by varying the feed condition and changing the feed gas in the batch reactor system using Ziegler–Natta catalysts system at a copolymerization temperature of 10°C. The 13C‐NMR tested by a 21.61‐ppm resonance peak indicated the incorporation of ethylene to propylene chains that could build up the microstructure of the block copolymer chain. Differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and dynamic mechanical analysis (DMA) results also confirmed these conclusions. Under these conditions, the morphology of copolymer trapped in PP matrix could be observed and the copolymer Tg would decrease when the amount of PP‐co‐EP was increased. DMA study also showed that PP‐co‐EP is good for the polypropylene reinforcement at low temperature. Moreover, the PP‐co‐EP content has an effect on the crystallinity and morphology of polymer blend, i.e., the crystallinity of polymer decreased when the PP‐co‐EP content increased, but tougher mechanical properties at low temperature were observed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3609–3616, 2007
Synthesis and luminescence studies of poly(vinyl acetate)–Eu (III) coordination compound
Authors: Wu Zhichuan , Wang Xueqian , Tao Tingxian , Zhang Yudong , Liu Yi , Fong Hao
Published: December 2006

In this research, the polymeric coordination compound of PVAc–Eu (III) was synthesized, and the formation of coordination bonding between Eu (III) and the carbonyl oxygen in PVAc was investigated by Fourier transform infrared (FT‐IR) spectroscopy, Raman spectroscopy (RS), and X‐ray photoelectron spectroscopy (XPS). The luminescent characteristics/properties of the prepared PVAc–Eu (III) were studied using fluorescence spectroscopy (FS). The results indicated that (1) the interaction/association between PVAc and Eu (III) in the prepared PVAc–Eu (III) was coordination bonding instead of weak physical adsorption, and (2) the photoluminescence intensity of PVAc–Eu (III) was approximately three times that of EuCl3. This research provided a theoretical foundation for the potential use of PVAc–Eu (III) as an innovative polymeric luminescent material, particularly for the applications in areas such as adhesives, coatings, textiles and others, the areas in which PVAc is an important raw material. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3617–3622, 2007
Morphologies and properties of poly(phthalazinone ether sulfone ketone) matrix ultrafiltration membranes with entrapped TiO2 nanoparticles
Authors: Li Jin‐Bo , Zhu Jie‐Wu , Zheng Mao‐Sheng
Published: December 2006

Poly(phthalazine ether sulfone ketone) (PPESK) is a newly developed membrane material with superior thermal stability and comprehensive properties. Titanium dioxide (TiO2)‐entrapped PPESK ultrafiltration (UF) membranes were formed by dispersing uniformly nanosized TiO2 particles in the casting solutions. Initially, the inorganic nanoparticles were organically modified with silane couple reagent to overcome the aggregation and to improve the dispersibility in organic solvent. The membranes were prepared through the traditional phase inversion method. The effects of inorganic TiO2 nanoparticles on the membrane surface morphology and cross section structure were investigated using scanning electronic microscopy (SEM) and atomic force microscopy (AFM). Water contact angle (CA) measurement was conducted to investigate the hydrophilicity and surface wettability of the membranes. The influence of TiO2 on the permeability, antifouling, and tensile mechanical properties of the PPESK membranes were evaluated by UF experiments and tensile tests. The experimental results showed that the obtained TiO2‐entrapped PPESK UF membranes exhibit remarkable improvement in the antifouling and mechanical properties because of the introduction of TiO2 nanoparticles. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3623–3629, 2007
Semiinterpenetrating polymer networks of chitosan and L‐alanine for monitoring the release of chlorpheniramine maleate
Authors: Kumari Kamlesh , Kundu P. P.
Published: December 2006

In vitro studies have been carried on semiinterpenetrating polymer network (IPN) beads of chitosan–alanine as carrier for the controlled release of chlorpheniramine maleate (CPM) drug. A viscous solution of chitosan–alanine was prepared in 2% acetic acid solution, extruded as droplets by a syringe to NaOH–methanol solution and crosslinked using glutaraldehyde as a crosslinker. The swelling behavior of crosslinked beads in different pH solutions was measured at different time intervals. The swelling behavior was observed to be dependent on pH and degree of crosslinking. The structural and morphological studies of beads were carried out by using a scanning electron microscope. The drug release experiments of different drug loading capacity beads were performed in solutions of pH 2 and pH 7.4 using CPM as a model drug. The concentration of the released drug was evaluated using UV spectrophotometer. The results suggest that chitosan–alanine crosslinked beads are suitable for controlled release of drug. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3751–3757, 2007
2‐Mercapto thioxanthone as a chain transfer agent in free‐radical polymerization: A versatile route to incorporate thioxanthone moieties into polymer chain‐ends
Authors: Karasu Feyza , Arsu Nergis , Yagci Yusuf
Published: December 2006

2‐Mercapto thioxanthone (TX‐SH) was used as a chain transfer agent in free‐radical polymerization of methyl methacrylate (MMA) and styrene (St), by using 2,2′‐azobisisobutyronitrile (AIBN) as an initiator at 70°C. Chain transfer constants were found to be 1.41 and 0.12 for St and MMA, respectively. The use of TX‐SH as a chain transfer agent leads to the formation of polymers with thioxanthone (TX) end groups. The incorporation TX moiety was confirmed by spectral measurements. Polymers obtained this way were used as triplet photosensitizer in free‐radical polymerization of MMA in the presence of a hydrogen donor such as N‐methyldiethanolamine (MDEA). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3766–3770, 2007
Polypropylene/carbon nanotube nanocomposite fibers: Process–morphology–property relationships
Authors: Jose Moncy V. , Dean Derrick , Tyner James , Price Gary , Nyairo Elijah
Published: December 2006

This study is focused on aligning carbon nanotubes in polypropylene matrix by melt spinning. Two different weight percentages (0.5% and 1.0%) of nanotubes were used for the synthesis of the nanocomposite fibers. The effect of the nanotubes on the crystallization and mechanical behavior of polypropylene as well as the effect of draw ratio on the nanocomposite morphology and properties is also discussed. Correlation of fiber morphology and nanotube alignment was done using differential scanning calorimetry, wide‐angle X‐ray diffraction, and transmission electron microscopy. Significant improvement in tensile modulus and tensile strength were observed, which is characteristic of a highly aligned nanotube system. A substantial vincrease in the onset of decomposition was observed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3844–3850, 2007
Adsorption of surfactant by hydrophobically modified poly[2‐(diethylamino)ethylmethacrylate‐co‐N‐vinyl‐2‐pyrrolidone/octadecyl acrylate)] hydrogels and effect of surfactant adsorption on the volume phase transition
Authors: Caykara Tuncer , İzol Demet , Birlik Gökçen , Akaoğlu Barış
Published: December 2006

Hydrophobically modified poly[2‐(diethylamino)ethylmethacrylate‐co‐N‐vinyl‐2‐pyrrolidone/octadecyl acrylate) [P(DEAEMA‐co‐NVP/OA)] hydrogels were synthesized by free‐radical crosslinking copolymerization of 2‐(diethylamino)ethylmethacrylate (DEAEMA), N‐vinyl‐2‐pyrrolidone (NVP) with different amounts of hydrophobic comonomer octadecyl acrylate (OA) in tert‐butanol with ethylene glycole dimethacrylate (EGDMA) as a crosslinker. The swelling equilibrium of the hydrogels was investigated as a function of temperature and hydrophobic comonomer content in aqueous solutions of the anionic surfactant sodium dodecyl sulfate (SDS) and the cationic surfactant dodecyltrimethylammonium bromide (DTAB). The results indicated that the swelling behavior and temperature sensitivity of the hydrogels were affected by the type and concentration of surfactant solutions. Additionally, the amount of the adsorbed SDS and DTAB molecules onto the hydrogels was determined by fluorescence measurements. An increase of OA content in the hydrogel caused an increase in the amount of adsorbed surfactant molecules in both media. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3771–3775, 2007
Pseudohalogens in atom transfer radical polymerization of methyl methacrylate
Authors: Singha Nikhil K. , German A. L.
Published: December 2006

In recent advances in controlled radical polymerization, atom transfer radical polymerization (ATRP) has achieved increasing interest. This investigation reports the ATRP of methyl methacrylate (MMA) using pseudohalogens as initiator as well as an anion for copper catalyst. The results were compared with the conventional halide system. Different pseudohalides were used as the initiator for the ATRP of MMA in combination with CuX (X = pseudohalide or halide) as the catalyst. Pseudohalide initiator in combination with Cu(halide) catalyst leads to inefficient ATRP due to slow initiation. Pseudohalide initiator in combination with Cu(pseudohalide) catalyst leads to uncontrolled or no polymerization. The polymers were characterized by using GPC, IR, MALDI‐TOF‐MS, and TGA analysis. IR and MALDI analysis showed that the resultant polymer had pseudohalide as the end group. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3857–3864, 2007
Iron(III) complexed with radiation‐grafted acrylic acid onto poly(tetrafluoroethylene‐co‐perfluorovinyl ether) films
Authors: El‐Sawy Naeem M. , Ali Z. I.
Published: December 2006

To introduce functional moieties to a poly(tetrafluoroethylene‐co‐perfluorovinyl ether) film, graft copolymerization of vinyl monomers such as acrylic acid was attempted by a simultaneous technique in aqueous solution using γ‐irradiation. The graft copolymers were complexed with the Fe(III) in aqueous solution. The grafted copolymer–metal complexes were examined by infrared (IR), ultraviolet/visible, energy‐dispersive X‐ray spectroscopy, and electron spin resonance techniques. The effect of temperature on the trunk copolymer, untreated grafted, and treated grafted copolymer films was investigated by IR and thermogravimetric analysis. The overall results suggest octahedral structure for Fe(III) and revealed the high stability of the obtained ligand–metal complexes. Furthermore, scanning electron microscope investigation of the grafted and modified films, both unheated and heated (200°C), showed changes in the structure and surface morphology. Promising results were achieved enhancing the practical applications of modified grafted membranes in the recovery of metal ions from aqueous systems. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 4065–4071, 2007
Effect of different salts on electrospinning of polyacrylonitrile (PAN) polymer solution
Authors: Qin Xiao‐Hong , Yang En‐Long , Li Ni , Wang Shan‐Yuan
Published: December 2006

Electrospinning is a relatively simple method to produce submicron fibers from solutions of different polymers and polymer blends. If the solution is absolutely insulating, or the applied voltage is not high enough that electrostatic force cannot overcome the surface tension, then no fiber can be produced by electrospinning; however, if some salt is added in the solution, the problem can be overcome. The effect of different salts on electrospinning of polyacrlonitrile (PAN) polymer solution was investigated in this article. The various inorganic salts used in this work include LiCl, NaNO3, NaCl, and CaCl2.The results show that when the salts were added, respectively, into different concentrations of PAN solution, the order of conductant was LiCl > NaNO3 > CaCl2 > NaCl > no salt added. Viscosity and shearing strength of electrospinning solutions are slightly affected by the adding of salts and mainly affected by the changes in concentration of PAN electrospinning solutions. The diameter of nanofibers electrospun by solutions with different salts size down as follows: LiCl > NaNO3 > CaCl2 > NaCl. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3865–3870, 2007
Preparation and multifunctional application of meso‐chitosan for the woolen process
Authors: Hsieh Sung‐Huang , Ciou Jyun‐Hao , Wang Jian‐Jhong
Published: December 2006

This study used chitosan deacetylated to different degrees to process woolen fabrics via the nanometrization of sodium hydroxide of different concentrations. The analysis and determination of the bacterial resistance, shrink resistance, Fourier transform infrared, and dyeability were then carried out for the processed substances. The particle diameter was measured with light scattering and scanning electron microscopy. It was then reduced with 5% and higher concentrations of NaOH, in which the particle diameter was 150–750 nm. As for bacterial resistance, the processed cloth that was not oxidized by H2O2 had better bactericidal and bacteriostatic effects than the cloth that underwent the oxidation process. Chitosan and meso‐chitosan had a bacterial‐resistance effect on the woolen fabrics. The processed cloth also had a better shrink‐resistance rate, but the effect of nanometrization was not obvious. For the dyeability of the woolen fabrics, meso‐chitosan was better than chitosan. The higher degree of deacetylation of chitosan slightly improved the dyeability. The dyeability increased a little as the temperature of the curing treatment rose and the time of the curing treatment was extended. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 4080–4086, 2007
Analysis of the fluid–structure interaction in the optimization‐based design of polymer sheeting dies
Authors: Wang Qi , Smith Douglas E.
Published: December 2006

A polymer‐sheeting‐die‐design methodology is presented that integrates a simulation of the polymer melt flow and die‐cavity deformation with numerical optimization to compute a die‐cavity geometry capable of giving a nearly uniform exit flow rate. Both the polymer melt flow and sheeting‐die deformation are analyzed with a general‐purpose finite‐element program. The approach includes a user‐defined element that is used to evaluate the purely viscous non‐Newtonian flow in a flat die. The flow analysis, which is simplified with the Hele–Shaw approximation, is coupled to a three‐dimensional finite‐element simulation for die deformation. In addition, shape optimization of a polymer sheeting die is performed by the incorporation of the coupled analyses in our constrained optimization algorithm. A sample problem is discussed to illustrate the die‐design methodology. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3994–4004, 2007
Influence of casting conditions on the properties of sulfonated poly(ether ether ketone ketone)/phosphotungstic acid composite proton exchange membranes
Authors: Xu Xianfeng Li, Dan , Zhang Gang , Wang Zhe , Zhao Chengji , Na Hui
Published: December 2006

The sulfonated poly(ether ether ketone ketone)/phosphotungstic acid (SPEEKK/PWA) composite membranes were researched for proton exchange membranes. The effect of casting condition on the properties of membranes was studied in detail. The study showed that the casting condition has great influence on the membrane properties because of the hydrogen bond between the SPEEK and PWA and the interaction between the SPEEKK and dimethylformamide (DMF). The PWA particles are well crystallized on the surface when the velocity of the solvent volatilization is very slow under the SEM. The study will favor further research on excellent composite membranes for proton exchange membrane fuel cells. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 4020–4026, 2007
Synthesis, characterization, and solution properties of an acrylamide‐based terpolymer with butyl styrene
Authors: Zhong Chuanrong , Huang Ronghua , Zhang Xi , Dai Hua
Published: December 2006

The terpolymers (PASA) with acrylamide (AM), butyl styrene (BST), and sodium 2‐acrylamido‐2‐methylpropane sulfonate (NaAMPS) were synthesized by the micellar free radical copolymerization technique. The polymer composition was determined by the elemental analysis, and the block structure of PASA was characterized directly by DSC measurement. Incorporation of NaAMPS into the terpolymers may improve the water solubility and intermolecular association, and the feed amount of BST, sodium dodecyl sulfate (SDS) amount, and the total monomer concentration in the polymerization can influence apparently the viscosities of PASA. The polymer exhibits excellent viscosification effect, salt‐thickening, temperature‐thickening, thixotropy, pseudoplastic behavior or shear‐thickening relative to the BST content in PASA, excellent antiaging property at 85°C, and a dramatic increase in solution viscosity by the addition of little amount of SDS. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 4027–4038, 2007
Silk grafting with methacrylic monomers: Process optimization and comparison
Authors: Ferrero Franco , Periolatto Monica , Luraschi Marco
Published: December 2006

The process of silk weighting with methacrylamide (MAA) initiated by ammonium persulfate was studied to optimize the operating conditions to obtain high yields of grafted monomer. The influence of MAA concentration, liquor ratio, concentration of initiator, contact and heating time, acidification, and swelling agents were considered, and optimum operating conditions were outlined. Moreover, various monomethacrylates and dimethacrylates were grafted onto silk as alternative to methacrylamide. Most of these showed graft yields higher than MAA in the same operating conditions and some were found suitable for silk weighting since the weighted fibers show soft hand and good dyeing behavior. DSC and TGA analyses of grafted silk enabled to evaluate the influence of various monomers on the thermal behavior of the weighted fibers. Moreover, on the basis of DSC data, a correlation between the calculated enthalpy of grafted polyMAA and monomer content was studied. The molecular structure of silk grafted with methacrylic monomers was finally characterized by FTIR analysis. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 4039–4046, 2007
Nanoscale surface roughening of mulberry silk by monochromatic VUV excimer lamp
Authors: Periyasamy S. , Gupta Deepti , Gulrajani M. L.
Published: December 2006

Surface treatment of mulberry silk was carried out using a VUV excimer lamp (172 nm). The changes occurring in morphology and physical properties of silk were studied. The nanopores created on the surface of treated samples were quantitatively analyzed using a high resolution scanning electron microscope. The physical and chemical changes taking place in silk fabric on irradiation were studied through measurement of wetting and wicking time, weight loss, crystallinity, and strength. Effect of irradiation time and distance from the lamp on these properties was also studied. Results show that wettability and wickability of silk improved significantly on exposure before stabilizing at 5 min irradiation time while the weight loss continued to increase. The effect of irradiation was negligible when the distance of the sample from the lamp became >15 mm. The effect of irradiation on tensile strength was found to be insignificant. Presence of moisture in silk hindered the effect of irradiation. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 4102–4106, 2007
Surface and barrier properties of hybrid nanocomposites containing silica and PEO segments
Authors: Malucelli Giulio , Priola Aldo , Amerio Ezio , Pollicino Antonino , di Pasquale Giovanna , Pizzi Diego , Grazia de Angelis Maria , Doghieri Ferruccio
Published: December 2006

Hybrid organic–inorganic nanocomposites containing PEO segments linked to a methacrylate network were prepared through a dual‐curing process, which involved photopolymerization and condensation of alkoxysilane groups. A system based on an α,ω‐dimethacrylate PEO oligomer (BEMA 1400) added with methacryloyl‐oxypropyl‐trimethoxysilane (MEMO) and tetraethoxysilane (TEOS) was used. The surface properties of the obtained films were investigated through XPS analyses and contact angle measurements. A selective enrichment of the MEMO additive towards the outermost layers of the films was evidenced either in the presence or in the absence of TEOS. SEM analyses were performed on the cross section of the films coated on PET substrates, determining the film composition at different depth by EDS analysis. The Si content was found constant, moving from the PET surface towards the air–surface of the films. The barrier properties, with respect to oxygen, of the hybrid films coated on a PET substrate were measured. A decrease of the permeability and of the oxygen transmission rate using hybrid coatings was observed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 4107–4115, 2007
Shape‐memory behavior of thermally stimulated polyurethane for medical applications
Authors: Baer G. , Wilson T. S. , Matthews D. L. , Maitland D. J.
Published: December 2006

Shape memory polymers (SMPs) have been of great interest because of their ability to be thermally actuated to recover a predetermined shape. Medical applications in clot extracting devices and stents are especially promising. We investigated the thermomechanical properties of a series of Mitsubishi SMPs for potential application as medical devices. Glass transition temperatures and moduli were measured by differential scanning calorimetry and dynamic mechanical analysis. Tensile tests were performed with 20 and 100% maximum strains, at 37 and 80°C, which are respectively, body temperature and actuation temperature. Glass transitions are in a favorable range for use in the body (35–75°C), with high glassy and rubbery shear moduli in the range of 800 and 2 MPa respectively. Constrained stress–strain recovery cycles showed very low hysteresis after three cycles, which is important to know for preconditioning of the material to ensure identical properties during applications. Isothermal free recovery tests showed shape recoveries above 94% for MP5510 thermoset SMP cured at different temperatures. One material exhibited a shape fixity of 99% and a shape recovery of 85% at 80°C over one thermomechanical cycle. These polyurethanes appear particularly well suited for medical applications in deployment devices such as stents or clot extractors. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3882–3892, 2007
Destabilization of model silica dispersions by polyelectrolyte complex particles with different charge excess, hydrophobicity, and particle size
Authors: Mende Mandy , Schwarz Simona , Petzold Gudrun , Jaeger W.
Published: December 2006

Nonstoichiometric polyelectrolyte complex dispersions (PECs) with different charge excess and hydrophobicity as well as different average hydrodynamic particle size were used to induce flocculation of oppositely charged silica dispersions. PECs were formed with poly(diallyldimethylammonium chloride) (PD) as polycation and poly(styrene‐p‐sodium sulfonate) (NaPSS) and poly(acrylamide‐co‐sodium acrylate) (PR2540) as polyanions. PD was used as single polymer flocculant too. Flocculation process was characterized by optical densities of supernatants OD500, by UV/VIS spectrometry, and determination of average floc sizes D(v; 0.5) as well as volume distribution of floc sizes by laser diffraction and determination of sedimentation velocity s by means of LUMiFuge™ 114. It was found that the reaction process between silica and the used flocculants could be divided into three intervals (destabilization, flocculation optimum, and restabilization) as it is known for all other polymer flocculants. For an effective flocculation of a charged substrate, both electrostatic as well as hydrophobic interactions play an important role. The interval up to the beginning of the flocculation optimum is mainly ascertained by electrostatic interactions (the charge density of the flocculant) but the broadness of flocculation optimum depends largely on hydrophobic interactions. Hydrophobic interactions also play an important role for shear stability of the formed flocs. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3776–3784, 2007
Preparation and properties of magnetic polystyrene microspheres
Authors: Chen Zhijun , Peng Kai , Mi Yongli
Published: December 2006

Magnetic polystyrene nanospheres were efficiently prepared by using a new indirect process based on miniemulsion polymerization of styrene. The samples were characterized by X‐ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), X‐ray photoelectron spectroscopy (XPS), and vibrating‐sample magnetometry (VSM), respectively. The experimental results clearly show that the 3‐methacryloxypropyltrimethoxy silane was anchored onto the surface of the magnetic particles to form the vinyl end. The size of the magnetic particle is about 6–30 nm. The size of the magnetic particle capped with polystyrene is about 1–2 μm. The magnetic polystyrene spheres exhibit multidomain character, whereas the pure magnetic particles show single domain character. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3660–3666, 2007
Synergist flame retarding effect of ultrafine zinc borate on LDPE/IFR system
Authors: Wu Zhiping , Shu Wanyin , Hu Yunchu
Published: December 2006

The flame retardancy of low‐density polyethylene (LDPE) treated with complex flame retardant composed of ultrafine zinc borate (UZB) and intumescent flame retardant (IFR) have been investigated by limited oxygen index (LOI), UL‐94 test, thermogravimetric analysis (TGA), cone calorimeter test, scanning electron micrograph (SEM), energy‐dispersive spectrometer (EDS), and X‐ray diffraction (XRD). The results of LOI and UL‐94 test indicate the desired flame retardancy of LDPE is obtained when the mass ratio of UZB to IFR is 4.2 : 25.8 and the complex flame retardant mass content is 30% (based on LDPE). The results of cone calorimeter show that heat release rate (HRR) peak, total heat release (THR), and mass loss of LDPE/IFR/UZB decrease substantially when compared with those of LDPE/IFR. TGA results show that the residue of LDPE/IFR/UZB increases obviously than that of LDPE/IFR when the temperature is above 600°C. SEM indicates the quality of char forming of LDPE/IFR/UZB is superior to that of LDPE/IFR. The results of EDS and XRD indicate that boron orthophosphate (BPO4) and zinc‐contained compounds are formed in the residual char and these substances may play an important role in stabilizing the intumescent char structure and decrease the degradation speed substantially when subjected to high temperature. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3667–3674, 2007
Pyrolysis studies of polyethylene terephthalate/silica nanocomposites
Authors: Zheng Jin , Cui Ping , Tian Xingyou , Zheng Kang
Published: December 2006

The decomposition of pure polyethylene terephthalate (PET) and PET/silica nanocomposites was investigated by thermal gravimetry (TG) and pyrolysis‐gas chromatography/mass spectrometry (Py‐GC/MS). The influence of the nanosized silica on the pyrolysis properties of the composites was found from the results that the activation energies of decomposition and the residual carbon content increase with silica nanoparticles. It is deduced that the increase of the activation energies and the residual carbon content result from the adsorption of the decomposed products on the surface of silica. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Copolymerization of carbon dioxide and propylene oxide with zinc glutarate as catalyst in the presence of compounds containing active hydrogen
Authors: Gao L. J. , Xiao M. , Wang S. J. , Du F. G. , Meng Y. Z.
Published: December 2006

To enhance the catalytic copolymerization of CO2 and propylene oxide catalyzed by zinc glutarate, the influence of trace of water, ethanol, and propanal on the catalytic activity, the resulted copolymer structure, and the molecular weight and molecular weight distribution of the copolymer were investigated extensively. The experimental results showed that the catalytic activity decreased remarkably in the presence of either trace of ethanol or water, but increased in the presence of trace of propanal. Both 1H‐NMR and 13C‐NMR spectra suggested that the content of carbonate linkages of resulted copolymer was not effected obviously in the presence of above‐mentioned impurities, giving completely alternating poly(propylene carbonate) (PPC). GPC results indicated that these impurities reduced the molecular weights but broadened the molecular weight distributions of resulted copolymers. Finally, the byproduct contents including both propylene carbonate determined by GC and polyether increased with the increase of three impurity concentrations. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Synthesis and colloidal stability of poly(N‐isopropylacrylamide) microgels with different ionic groups on their surfaces
Authors: Zha Liusheng , Li Lan , Bao Laiyan
Published: December 2006

Temperature‐sensitive poly(N‐isopropylacry‐lamide) (PNIPAM) microgels with sulfate, amidino, or carboxylic groups on their surfaces, were synthesized by precipitation polymerization based on ammonium persulfate (APS), 2,2′‐azobis(amidinopropane) dihydrochloride (V50), or 4,4′‐azobis(4‐cyanovaleric acid) (ACVA) as initiator, respectively. Their particle sizes and swelling ratios depended on the reaction pH due to the pH dependence of the ionization degree of the decomposed fragments originating from the initiators and their hydrophilicity–hydrophobicity. The more hydrophobic initiators partitioned into the interior of the PNIPAM microgels under certain pH conditions initiated the crosslinking reaction between the PNIPAM chains, leading to higher crosslinking density of the microgels resulting in their smaller swelling ratio. pH dependence of surface charge density of the microgels with amidino groups or carboxylic acid groups on their surfaces was evidenced by the variation of their ζ‐potentials as a function of pH. Correspondingly, due to their pH dependence of electrostatic repulsive effect, the colloidal stability of the microgels with amidine groups or carboxylic acid groups on their surfaces was dependent on the pH value of dispersion medium. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3893–3898, 2007
Wear and mechanical properties of reactive thermotropic liquid crystalline polymer/unsaturated polyester/glass fiber hybrid composites
Authors: Yu Xianbao , Wei Chun , Xu Deng , Lu Chihua , Yu Jinhong , Lu Shaorong
Published: December 2006

To improve the performance of unsaturated polyester (UP) under cold‐heat alternate temperature, self‐synthesized reactive thermotropic liquid crystalline polymer (TLCP)‐methacryloyl copolymer (LCMC), UP, and glass fiber (GF) hybrid composites was prepared by molding technology. The apparent activation energy and crystal behavior analysis of LCMC/UP blends were investigated by Differential scanning calorimetry and X‐ray diffraction (XRD), respectively, the results showed that the addition of LCMC can reduce apparent activation energy and accelerate the curing reaction of UP, the XRD analysis indicated that the crystal phase of LCMC still exist in the blends after blending with UP. The effect of LCMC content on the properties of LCMC/UP/GF hybrid composites such as impact strength, bending strength, and ring‐on‐block wear were also investigated through static mechanical tests and wear tests. The mechanical properties of hybrid composites increased significantly because of the addition of LCMC. The wear tests showed that LCMC can improve the wear resistance of the UP/GF/LCMC hybrid composites even though the content of LCMC was at a relatively low level (5–7.5 wt %). This makes it possible to develop novel kind of UP‐based materials with good wear resistance for various applications. The Worn surface was observed by scanning electron microscopy (SEM) and the mechanism for the improvement is discussed in this paper. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3899–3906, 2007
Comparative behavior of PVA/PAN and PVA/PES composite pervaporation membranes in the pervaporative dehydration of caprolactam
Authors: Zhang Lei , Yu Ping , Luo Yunbai
Published: December 2006

Flat‐sheet composite membranes were developed by the traditional phase inversion technique using poly;(vinyl alcohol) (PVA). PVA composite pervaporation (PV) membranes were prepared with crosslinked PVA selective layer and porous polyacrylonitrile (PAN) and polyether sulfone (PES) substrate layer material as supports for separating heat sensitivity substance ε‐caprolactam (CPL) from CPL/water mixtures. Glutaraldehyde was used as crosslinking agent. The effect of the composition of glutaraldehyde on membrane stability and structure were investigated. The operating parameters, such as feed concentration and operating temperature, remarkably affected PV performance of the composite membranes. The composite membranes with PVA casted on PAN (PVA/PAN) showed superior PV performance than that casted on PES (PVA/PES). This study has also shown that the type of porous support plays an important role in the PV performance. As a result, this work has presented the information needed of the behavior of PV membranes for dehydration applications of industrial caprolactam. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 4005–4011, 2007
Dynamic mechanical properties and morphology of high‐density polyethylene/CaCO3 blends with and without an impact modifier
Authors: Yang Yu‐Lin , G'Sell Christian , Hiver Jean‐Marie , Bai Shu‐Lin
Published: December 2006

Dynamic mechanical analysis and differential scanning calorimetry were used to investigate the relaxations and crystallization of high‐density polyethylene (HDPE) reinforced with calcium carbonate (CaCO3) particles and an elastomer. Five series of blends were designed and manufactured, including one series of binary blends composed of HDPE and amino acid treated CaCO3 and four series of ternary blends composed of HDPE, treated or untreated CaCO3, and a polyolefin elastomer [poly(ethylene‐co‐octene) (POE)] grafted with maleic anhydride. The analysis of the tan δ diagrams indicated that the ternary blends exhibited phase separation. The modulus increased significantly with the CaCO3 content, and the glass‐transition temperature of POE was the leading parameter that controlled the mechanical properties of the ternary blends. The dynamic mechanical properties and crystallization of the blends were controlled by the synergistic effect of CaCO3 and maleic anhydride grafted POE, which was favored by the core–shell structure of the inclusions. The treatment of the CaCO3 filler had little influence on the mechanical properties and morphology. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3907–3914, 2007
Synthesis of conducting polyaniline/TiO2 composite nanofibres by one‐step in situ polymerization method
Authors: Bian Chaoqing , Yu Yijun , Xue Gi
Published: December 2006

Conducting polyaniline (PANI)/titanium dioxide (TiO2) composite nanofibres with an average diameter of 80–100 nm were prepared by one‐step in situ polymerization method in the presence of anatase nano‐TiO2 particles, and were characterized via Fourier‐transform infrared spectra, UV/vis spectra, wide‐angle X‐ray diffraction, thermogravimetric analysis, and transmission electron microscopy, as well as conductivity and cyclic voltammetry. The formation mechanism of PANI/TiO2 composite nanofibres was also discussed. This composite contained ∼ 65% conducting PANI by mass, with a conductivity of 1.42 S cm−1 at 25°C, and the conductivity of control PANI was 2.4 S cm−1 at 25°C. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Surface‐initiated atom transfer radical polymerization from Mg(OH)2 nanoparticles to prepare the well‐defined polymer‐Mg(OH)2 nanocomposites
Authors: Chang Ming‐Jen , Tsai Jen‐Yun , Chang Chia‐Wei , Chang Hwai‐Ming , Jiang George J.
Published: December 2006

Well‐defined polymer‐Mg(OH)2 nanocomposites were prepared by atom transfer radical polymerization (ATRP). The ATRP initiators were covalently attached to the Mg(OH)2 by esterification of 2‐chloropropionyl chloride with hydroxyl group. The amount of polymer grafted from Mg(OH)2 can be controlled using a different catalyst system and adding a small amount of polar solvent. The well‐defined diblock copolymer, consisting of poly(styrene) (PS) and poly(methyl methacrylate) (PMMA) were synthesized. The products were characterized by nuclear magnetic resonance, Fourier transform infrared, differential scanning calorimetry, and thermal gravimetric analysis. The morphologies of PS/PMMA and PS/PMMA/Mg(OH)2‐g‐PS‐b‐PMMA blends are compared by using a scanning electron microscope. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3680–3687, 2007