bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of magnetization on the gel structure and protein electrophoresis in polyacrylamide hydrogel nanocomposites
Authors: Thompson Jeffery W. , Stretz Holly A. , Arce Pedro E. , Gao Hongsheng , Ploehn Harry J. , He Jibao 
Published: May 2012

AbstractIn this study, polyacrylamide nanocomposite hydrogels were formulated in combination with sodium montmorillonite (MMT) in the presence of a 2‐T magnetic field. This top‐down nanomanufacturing approach led to interesting changes in the internal structure of the gel and ultimately to a dramatic improvement in the ability of the composite to separate the two protein probes, ovum serum albumin and carbonic anhydrase. The morphology of the nanocomposite hydrogel was analyzed with cryogenic scanning and transmission electron microscopy, wide‐angle X‐ray diffraction, and small‐angle scattering to determine whether morphological changes would correlate with this improved separation. As the volume fractions of MMT were well under 1% in this study (because of aqueous swelling), scattering data were dominated by the polymer structure. Significant morphological changes were noted at two length scales: (1) the hydrogel cell structure, at hundreds of nanometers, appeared to exhibit changes in the anisotropic orientation with magnetization, and (2) the polyamide structure, at tens of nanometers, exhibited decreasing pore size (small‐angle X‐ray scattering). The separation data correlated most closely with a reduction in pore size; however, an additional contribution to separation from local electrostatic effects from the presence of charged MMT in the cell walls could not be discounted. The change in the pore size associated with processing may have been due to the MMT presence altering the diffusion rates of the reactants during polymer formation. The method demonstrated herein could be used ultimately to separate proteins in their native state, with the potential retention of function for downstream applications, such as novel detection techniques or purification. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synthesis of an azo macromolecular initiator composed of polyamide 4 and its initiation activity for the radical polymerization of vinyl monomers
Authors: Kawasaki Norioki , Yamano Naoko , Takeda Sahori , Ando Hisanori , Nakayama Atsuyoshi 
Published: May 2012

AbstractPolyamide 4 containing an azo group (azo‐PA4) was synthesized by the ring‐opening polymerization of 2‐pyrrolidone when 4,4′‐azobiscyanopentanoyl chloride was used as an initiator. It was possible to control the molecular weight (MW) of the azo‐PA4s through the concentration of the initiator to some extent, and the highest weight‐average MW obtained was 35 × 103. To assess the initiation activity of the azo‐PA4 for radical polymerization, styrene (St) was used as a vinyl monomer. The azo‐PA4 was found to initiate the radical polymerization of St to produce polymers. Analyses by FT‐IR spectroscopy, 1H‐NMR, and differential scanning calorimetry after the homopolymers [polyamide 4 (PA4) and polystyrene (PSt)] were removed by Soxhlet extraction showed that the remaining polymer was PA4‐block‐PSt. Azo‐PA4 was also found to have an initiation activity for other vinyl monomers (methyl methacrylate, vinyl acetate, etc.). © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Novel redox‐active polycarbazole‐functionalized polycatechol network films produced by controlled electropolymerization
Authors: Huang Yao , Lu Baoyang , Xu Jingkun , Zhu Guang , Chen Shuai , Yue Ruirui 
Published: May 2012

AbstractA novel precursor, 1,2‐bis[6‐(9H‐carbazol‐9‐yl)hexyloxy] benzene (BCHB), was successfully synthesized. Its polycarbazole‐functionalized polycatechol network films, poly{1,2‐bis[6‐(9H‐carbazol‐9‐yl)hexyloxy] benzene} (PBCHB), with good redox activity were formed by the direct anodic oxidation of BCHB in CH2Cl2 and boron trifluoride diethyl etherate binary solvent solution. Ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, 1H‐NMR, and matrix‐assisted laser desorption ionization–time of flight mass spectrometry were used to characterize the polymers. The results indicate that the network polymers could be synthesized electrochemically with different polymerized units by controlled electropolymerization. The PBCHB films prepared at low potential were oligomers with short conjugation lengths and were soluble in common organic solvents, whereas the polymers with long conjugation lengths and hyperbranched network structures obtained at high potential were insoluble. The electrosynthesized polymers exhibited blue emission maxima around 450 nm and were much more redshifted than their monomer. The emissions were also brighter; this indicated the polymers are potential good blue‐light emitters. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Analytical estimate for curing‐induced stress and warpage in coating layers
Authors: Jansen K. M. B. , de Vreugd J. , Ernst L. J. 
Published: May 2012

AbstractA thermoset coating that is applied to an elastic substrate will develop residual stresses during curing because of polymerization shrinkage of the resin. This shrinkage only partly contributes to the residual stresses because, before gelation, the stresses relax completely. In this study, we developed explicit analytical expressions for the curing efficiency factor, the residual stresses, and the resulting warpage. We did this by assuming that after gelation, the material was in its rubbery state and that viscoelastic effects were absent. A difference between the free and constrained warpages during curing was made. The analytical warpage models were shown to give results comparable to those of the numerical calculations with a fully curing‐dependent viscoelastic material model. Furthermore, for the first time, accurate analytical expressions for the stress‐free temperature and stress‐free strain were obtained. With these expressions, the effect of curing shrinkage on the residual stresses could easily be incorporated into existing (numerical) stress analysis without the need for extensive curing‐dependent viscoelastic material models. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2012
Synthesis and characterization of molecularly imprinted poly(methacrylic acid)/silica hybrid composite materials for selective recognition of lincomycin in aqueous media
Authors: Lv Yun‐Kai , Wang Li‐Min , Yan Shuai‐Lei , Wang Xiao‐Hu , Sun Han‐Wen 
Published: May 2012

AbstractA novel molecular imprinting method for the preparation of molecularly imprinted poly(methacrylic acid)/silica hybrid composite materials (MIP‐HCMs) for the selective recognition of lincomycin (LIN) in aqueous media by prepolymerization and free‐radical copolymerization was investigated. In this study, methacrylic acid was selected as the functional monomer, methacryloxypropyltrimethoxysilane was used as the crosslinker, and tetraethoxysilane was used as the inorganic precursor. MIP‐HCM was characterized by FTIR spectroscopy, the Brunauer–Emmett–Teller method, and TGA. The selectivity of the sorbent was investigated by a batch competitive binding experiment with an aqueous LIN and clindamycin (CLI) mixture. The selectivity coefficient for LIN in the presence of CLI was 6.27, whereas the relative selectivity coefficient between LIN and CLI was 5.83. The absorption capability of MIP‐HCM and the selectivity coefficient were much higher than those of the nonimprinted blank polymer. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2012
Synthesis and characterization of poly(ether carbonate)s by melt‐phase interchange reactions of dihydroxy compounds with alkylene and arylene diphenyl dicarbonates containing ether groups
Authors: Al‐Qalawi Hussam R. , Sweileh Bassam A. , Kailani Mohammad H. 
Published: May 2012

AbstractA new method of synthesis of poly(ether carbonate)s based on interchange reactions of dihydroxy compounds with alkylene and arylene diphenyl dicarbonates containing ether group was presented. The diphenyl dicarbonate monomers were prepared from phenyl chloroformate and dihydroxy compounds containing ether group (e.g., diethylene glycol, bis(2‐hydroxyethyl ether) of bisphenol A, and 4,4′‐oxydiphenol). The process consisted of a precondensation step under a stream of dry argon followed by a melt polycondensation at 230 or at 250°C under vacuum. Four series of poly(ether carbonate)s were prepared using this approach. Using alkylene and arylene diphenyl dicarbonate‐containing ether groups as monomers, the polycondensation reaction with dihydroxy compounds led to the formation of poly(ether carbonate)s having inherent viscosity values up to 0.56 dL/g and high thermal stability. The glass transition temperature values of polycarbonates were in the range 7–122°C. The polymers were characterized by inherent viscosity and spectroscopic (Fourier transform infrared spectroscopy and 1H‐NMR and 13C‐NMR) and thermal (differential scanning calorimeteric and thermogravimetric) methods. This approach may permit the use of diphenyl dicarbonates containing other organic functional groups for the synthesis of polycarbonates containing those groups. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Photodegradation and biodegradation by bacteria of mulching films based on ethylene‐vinyl acetate copolymer: Effect of pro‐oxidant additives
Authors: Abrusci C. , Pablos J. L. , Marín I. , Espí E. , Corrales T. , Catalina F. 
Published: May 2012

AbstractThe photodegradation (432 h under irradiation of Xe‐Lamp‐solar filter) of an ethylene vinyl acetate (EVA) copolymer with vinyl acetate content of 9% was studied, and the effect of iron and calcium stearates was evaluated using different techniques such us attenuated total reflectance‐Fourier transform infrared spectroscopy (ATR‐FTIR), gel permeation chromatography (GPC), and thermal analysis methods (DSC and TGA). A re‐arrangement in crystallization and consequent decrease in thermal stability were found through differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), which were in agreement with the chain scission tendency. The presence of Ca and Fe pro‐oxidants additives in EVA films increased the ketone carbonyl formation and decreased the ester absorption band of the acetate respect to the pure EVA, as it was evidenced by the significant changes in Carbonyl Indexes found by FTIR. The activity of stearates has been also evaluated by chemiluminescence, where the temperature‐ramping tests under nitrogen showed the formation of a peroxide peak at lower temperature. The lower stability of the films containing pro‐oxidants was evidenced by the values of oxidation induction time (OIT) determined by DSC. The results were supported by GC‐MS, where the concentration of extracted products identified in the EVA containing pro‐oxidants was significant and a much greater decrease in molecular weight was determined by GPC, which confirmed the development of degradation for EVA with Ca and Fe stearates in comparison to pure EVA. Biodegradation of photodegraded EVA films were studied at 45°C during 90 days using a mixture of Bacillus (MIX) (B. cereus, B. megaterium, and B. subtilis) and, in parallel, by Brevibacillus borstelensis as reference strain. Biodegradation of EVA‐films was studied by Chemiluminescence, ATR‐FTIR and GC‐product analysis and the data confirm more efficient biodegradation on the materials containing pro‐oxidants. The chemiluminescence emissions due to decomposition of oxidation species was observed at lower temperatures on the biodegraded samples. Also, the drastic decrease of carbonyl index and the disappearance of photogenerated low molecular products with biodegradation were more efficient on the biodegraded films containing pro‐oxidants. EVA mineralization was evaluated by carbon dioxide measurement using indirect impedance technique. Biodegradation by B. borstelensis and MIX at 45°C was similar and exhibited a pronounced difference between the pure photodegraded EVA film (around 15% of mineralization) and the corresponding photodegraded films containing Ca and Fe stearates where biodegradation extent reached values of 23‐26% of biodegradation after 90 days. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Photopolymerization behavior and phase separation effects in novel polymer dispersed liquid crystal mixture based on urethane trimethacrylate monomer
Authors: Nataj Nahid Hosein , Jannesari Ali , Mohajerani Ezeddin , Najafi Farhood , Jashnsaz Hossein 
Published: May 2012

AbstractPolymer dispersed liquid crystals (PDLCs) are often formed by polymer induced phase separation, based on photopolymerization of multifunctional acrylate monomers. The emerged morphology is controlled by the interplay between polymerization rate and phase separation dynamics, which depends on different parameters such as monomer structure and functionality. In this work, a new PDLC formulation containing urethane trimethacrylate (UTMA) monomer is introduced, which has different molecular weight evolution, polymer gel point, and polymerization kinetics in comparison with some common ester acrylate (such as TMPTA and DPHPA) based PDLC compositions. UTMA is synthesized and characterized by Fourier transform infrared, 1H‐NMR, and 13C‐NMR spectroscopic techniques. Simultaneous examination of polymer evolution and LC phase separation by real‐time infrared spectroscopy shows that the UTMA based PDLC, which contains trifunctional urethane acrylate monomer, has greater amount of bond conversion, polymerization rate, and liquid crystal (LC) phase separation in comparison with TMPTA based PDLC. In spite of the acrylate monomers, which show gel point conversions as low as 1.83–5.72%, UTMA reaches to its maximum rate at 19.5% conversion, which causes higher phase separation and therefore greater LC domain size. The experimental results are explained more precisely by means of SEM and optical microscopy analyses. The results are confirmed by electro‐optics measurements. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synthesis and characterization of slow‐release nitrogen fertilizer with water absorbency: Based on poly(acrylic acid‐acrylic amide)/Na‐bentonite
Authors: Qin Shaohua , Wu Zhansheng , Rasool Aamir , Li Chun 
Published: May 2012

AbstractA novel slow‐release nitrogen fertilizer with high‐water absorbency (SRNFWA) was prepared by cross‐linking poly (acrylic acid‐acrylic amide)/bentonite and urea. The synthesis conditions were studied systematically and optimized by using the response surface methodology (RSM). Meanwhile, the effects of the concentration of cross‐linker, initiator, bentonite, and degree of neutralization of acrylic acid on WA were investigated. The SRNFWA was characterized by Fourier transform infrared (FTIR) spectroscopy, elemental analysis, and scanning electron microscopy (SEM). The results of SEM showed the undulant and coarse surface, facilitated the permeation of nutrition into the polymeric network. We also investigated the slow release property and release mechanism of the nitrogen from the network structure, and the WA in different external solutions. The released characteristic of nitrogen was less than 15% by the third day and reached up to almost 75% after 30 days in distilled water. The WA was 700 g g−1 and 150 g g−1 in distilled water and 0.9 wt % NaCl solutions, respectively. These studies exhibited the excellent slow‐release property and WA capacity of this polymer in 0.9 wt % NaCl solution and could be quite effective in improving the utilization of fertilizer and its water retention capacity simultaneously. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Study on the biocomposites with poly(ethylene glycol) dimethacrylate and surfaced‐grafted hydroxyapatite nanoparticles
Authors: Li Haibo , Fu Yi , Niu Rui , Zhou Ziyou , Nie Jun , Yang Dongzhi 
Published: May 2012

AbstractIn composites of hydroxyapatite (HA) nanoparticles with a polymer matrix, the aggregation of nanoparticles would induce structural defects. In order to improve the dispersibility of HA nanoparticles in poly(ethylene glycol) dimethacrylate (PEGDMA) matrix and enhance mechanical properties of the HA/PEGDMA composite as potential bone substitute material, surface‐grafted HA nanoparticles with poly(ethylene glycol) monomethacrylate (PEGMA) were prepared, and crosslinked with PEGDMA under UV light to form a composite. The structure of HA‐g‐PEGMA was characterized by X‐ray diffraction (XRD) and thermal gravimetric analysis (TGA). The dispersibility of HA‐g‐PEGMA nanoparticles in poly(PEGDMA) was evaluated by SEM. The mechanical properties of the composites were investigated by compressive test. The dispersibility of HA‐g‐PEGMA nanoparticles in poly(PEGDMA) matrix was better than the bare HA. At a 1 wt % content of loading, the strength of composites increased by 14%, and the modulus increased by 9%. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Mechanical and chemical stability of injection‐molded microcantilevers used for sensing
Authors: Urwyler Prabitha , Pascual Alfons , Kristiansen Per Magnus , Gobrecht Jens , Müller Bert , Schift Helmut 
Published: May 2012

AbstractUltraviolet‐ozone treatment is used as a standard surface cleaning procedure for removal of molecular organic contamination from analytical and sensing devices. Here, it is applied for injection‐molded polymer microcantilevers before characterization and sensing experiments. This article examines the effects of the surface cleaning process using commercial equipment, in particular on the performance and mechanical properties of the cantilevers. It can be shown that the first chemical aging process essentially consist of the cross linking of the polymer chains together with a physical aging of the material. For longer exposure, the expected thermo‐oxidative formation of carbonyl groups sets in and an exposure dependent chemical degradation can be detected. A process time of 20 min was found suitable as a trade‐off between cleaning and stability. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
A study on thermal behavior of a poly(VDF‐CTFE) copolymers binder for high energy materials
Authors: Singh Arjun , Soni P. K. , Shekharam T. , Srivastava Alok 
Published: May 2012

AbstractThis article describes a study on thermal behavior of poly(vinylidene fluoride‐chlorotrifluoroetheylene) [poly(VDF‐CTFE)] copolymers as polymeric binders of specific interest for high energy materials (HEMs) composites by thermal analytical techniques. The non‐isothermal thermogravimetry (TG) for poly (VDF‐CTFE) copolymers was recorded in air and N2 atmospheres. The results of TG thermograms show that poly(VDF‐CTFE) copolymers get degrade at lower temperature when in air than in N2 atmosphere. In the derivative curve, there was single maximum degradation peak (Tmax) indicating one‐stage degradation of poly(VDF‐CTFE) copolymers for all the samples. The other thermal properties such as glass transition temperature (Tg) and degradation temperature (Td) for poly(VDF‐CTFE) copolymers were measured by employing differential scanning calorimeter (DSC) technique. The kinetic parameters related to thermal degradation of poly(VDF‐CTFE) copolymers were investigated through non‐isothermal Kissinger kinetic method using DSC method. The activation energies for thermal degradation of poly(VDF‐CTFE) copolymers were found in a range of 218–278 kJ/mol. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
New amphiphilic sulfonic acid dopant‐cum‐templates for diverse conducting polyaniline nanomaterials
Authors: Shinde Shekhar D. , Jayakannan M. 
Published: May 2012

AbstractWe report new structurally identical polar head amphiphilic sulfonic acids as molecular templates to study the role of the polymerization routes on the solid state properties of polyaniline nanomaterials. Three long chain substituted phenols such as 3‐pentadecylphenol, renewable resource‐cardanol, and nonyl phenol are reacted with sultones to make new long tail amphiphiles. The amphiphilic molecules self‐organized as 4–6 nm tiny micelles in water which were employed as templates for polymerization. Emulsion, dispersion, and interfacial polymerization of aniline along with these new amphiphiles produced well‐defined polyaniline nanofibers, nanotapes, and nanospheres. Electron microscopic analysis revealed that the dopant structure and polymerization routes determine the morphology of the polyaniline nanomaterials. Absorbance studies revealed that the samples produced via interfacial route showed expanded polymer chain conformation as a result of unidirectional growth of the chains in the aqueous‐organic interface. Emulsion and dispersion route samples were produced in coil‐like chain conformation. Powder X‐ray analysis confirmed that the expanded conformation in the polyaniline backbone enhances the high solid state ordering, high percent crystallinity, and larger crystallite size compared to that of the samples with coil‐like conformation. Highly ordered interfacial route samples showed conductivity three orders of magnitude higher than that of the weakly packed polyaniline nanomaterials. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Synthesis and characterization of the 47‐residue heterodimeric antimicrobial peptide distinctin, featuring directed disulfide bridge formation
Authors: Mullen Daniel G. , Verardi Raffaello , Porcelli Fernando , Scaloni Andrea , Barany George , Veglia Gianluigi 
Published: May 2012

AbstractDistinctin, a 47‐residue heterodimeric peptide with potent antimicrobial activity, comprises two monomeric units linked covalently by a disulfide bond between Cys19 from the 22‐residue A chain and Cys23 from the 25‐residue B chain. Previous synthetic strategies involved assemblies of the two individual chains, followed by their co‐oxidation to form the connecting disulfide bridge, and resulted in a mixture of three species: two homodimers and one heterodimer. Here, we report synthesis of exclusively heterodimeric distinctin, using recently developed tactics for directed disulfide bridge formation. Material prepared this way was characterized and found to be suitable for more detailed structural studies. © 2012 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 98: 479–484, 2012.
Autologous reconstruction of massive enteroatmospheric fistulation with a pedicled subtotal lateral thigh flap
Authors: Lambe G , Russell C , West C , Kalaiselvan R , Slade D A J , Anderson I D , Watson J S , Carlson G L 
Published: May 2012

Abstract

Background
Reconstruction of massive contaminated abdominal wall defects associated with enteroatmospheric fistulation represents a technical challenge. An effective technique that allows closure of intestinal fistulas and reconstruction of the abdominal wall, with a good functional and cosmetic result, has yet to be described. The present study is a retrospective review of simultaneous reconstruction of extensive gastrointestinal tract fistulation and large full-thickness abdominal wall defects, using a novel pedicled subtotal thigh flap.

Methods
The flap, based on branches of the lateral circumflex femoral artery, was used to reconstruct the abdominal wall in six patients who were dependent on artificial nutritional support, with a median (range) of 4·5 (3–23) separate intestinal fistulas, within open abdominal wounds with a surface area of 564·5 (204–792) cm2. Intestinal reconstruction was staged, with delayed closure of a loop jejunostomy. Median follow-up was 93·5 (10–174) weeks.

Results
Successful healing occurred in all patients, with no flap loss or gastrointestinal complications. One patient died from complications of sepsis unrelated to the surgical treatment. All surviving patients gained complete nutritional autonomy following closure of the loop jejunostomy.

Conclusion
Replacement of almost the entire native abdominal wall in patients with massive contaminated abdominal wall defects is possible, without the need for prosthetic material or microvascular free flaps. The subtotal pedicled thigh flap is a safe and effective method of providing definitive treatment for patients with massive enteroatmospheric fistulation.