bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of the polymerization conditions on the swelling of a copolymer of AA/AMPS/BA via experimental design
Authors: Rosa Fátima , Bordado João , Casquilho Miguel 
Published: September 2009

AbstractTo study the effect of the polymerization conditions on swelling, a copolymer was synthesized from the monomers acrylamide (AA), 2‐acrylamido‐2‐methyl‐propanosulfonic acid (AMPS) andN,N‐methylenobisacrylamide (BA) as crosslinker by an inverse emulsion technique. The conditions were: concentration of organic solvent,s(an isoparaffinic hydrocarbon, commercially Isopar M), concentration of emulsifier,e(sorbitan trioleate, commercially Tween 85), and reaction temperature,T. These three variables (factors) were explored to achieve highest water absorbency, a 23factorial experimental design having been applied to find the main and two‐factor interaction effects of those variables on the swelling capacity. A predictive model including the factors for the swelling is proposed, allowing for the estimation of absorbency capacity in this type of copolymers. The results show that the optimum values of the variables given by the experimental design weres= 8.1,e= 1.0, andT= 49°C, with predicted swelling capacity of 1041 and experimental of 1014. The variables are relevant, with a preponderance ofs, and the effect of the square of temperature is also significant. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis and photovoltaic properties of polythiophene derivatives with side chains containing C60 end group
Authors: He Youjun , Hou Jianhui , Tan Zhan'ao , Li Yongfang 
Published: September 2009

AbstractA donor–acceptor double‐cable polythiophene derivative (PT‐F1) with side chain containing C60 end group was synthesized, and characterized by infrared, UV‐vis absorption and photoluminescence (PL) spectroscopy, and electrochemical cyclic voltammetry. Cyclic voltammogram of PT‐F1 shows the oxidation peak of the polymer main chains and the reduction peaks of the C60 end groups, indicating that there is no interaction between the polymer main chains and side chain C60 groups on the ground state. The UV‐vis absorption spectrum of PT‐F1 film is red‐shifted in comparison with that of its chloroform solution. The PL spectrum of the polymer main chain was quenched by the C60 pendant on the side chain. Polymer solar cell with the structure of ITO/PEDOT:PSS/PT‐F1/Ca/Al was fabricated. The power conversion efficiency of the device based on PT‐F1 reached 0.274% under the illumination of AM 1.5, 100 mW/cm2. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Influence of oil contents in dynamically cured natural rubber and polypropylene blends
Authors: Nakason Charoen , Kaewsakul Wisut 
Published: September 2009

AbstractMechanical, dynamic, thermal, and morphological properties of dynamically cured 60/40 NR/PP TPVs with various loading levels of paraffinic oil were investigated. It was found that stiffness, hardness, tensile strength, storage shear modulus, complex viscosity, glass transition temperature (Tg) of the vulcanized rubber phase, degree of crystallinity and crystalline melting temperature (Tm) of the polypropylene (PP) phase decreased with increasing loading levels of oil. This is attributed to distribution of oil into the PP and vulcanized rubber domains causing oil‐swollen amorphous phase and vulcanized rubber domains. An increasing trend of elastic response in terms of tension set and damping factor was observed in the TPVs with loading levels of oil in a range of 0–20 phr. It is supposed that a major proportion of oil was first preferably migrated into the PP phase and caused an abrupt decreasing trend of degree of crystallinity and Tm of the PP phase. The dispersed vulcanized rubber domains remained small as particles with a low degree of swelling. Increasing loading levels of oil higher than 20 phr caused a decreasing trend of elongation at break and elastomeric properties. Saturation of oil in the PP phase was expected and the excess oil was transferred to the rubber phase which thereafter caused larger swollen vulcanized rubber domains. The remaining amount of oil was able to separate as submicron pools distributed in the PP matrix. This caused lowering of Tg, Tm, crystallinity of PP phase as well as strength, elastomeric, and dynamic properties of the TPVs. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis and characterization of butyl acrylate/methyl methacrylate/glycidyl methacrylate latexes
Authors: Mishra Sujata , Singh Jagbir , Choudhary Veena 
Published: September 2009

AbstractThe butyl acrylate (BA)/methyl methacrylate (MMA), and glycidyl methacrylate (GMA) composite copolymer latex was synthesized by seeded emulsion polymerization technique taking poly(methyl methacrylate) (PMMA) latex as the seed. Four series of experiments were carried out by varying the ratio of BA : MMA (w/w) (i.e. 3.1 : 1, 2.3 : 1, 1.8 : 1, and 1.5 : 1) and in each series GMA content was varied from 1 to 5% (w/w). The structural properties of the copolymer were analyzed by FTIR, 1H‐, and 13C‐NMR. Morphological characterization was carried out using transmission electron microscopy (TEM). In all the experiments, monomer conversion was ∼99% and final copolymer composition was similar to that of feed composition. The incorporation of GMA into the copolymer chain was confirmed by 13C‐NMR. The glass transition temperature (Tg) of the copolymer latex obtained from the differential scanning calorimetry (DSC) curve was comparable to the values calculated theoretically. With increase in GMA content, particles having core‐shell morphology were obtained, and there was a decrease in the particle size as we go from 2–5% (w/w) of GMA. The adhesive strength of the latexes was found to be dependent on the monomer composition. With increase in BA : MMA ratio, the tackiness of the film increased while with its decrease the hardness of the film increased. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Reduction of volatile organic compound emission. II. Use of alkoxy‐modified silsesquioxane for compounding silica‐filled rubbers
Authors: Lin Chenchy J. , Hergenrother William L. , Hilton Ashley S. 
Published: September 2009

AbstractA class of alkoxy‐modified silsesquioxane (AMS) containing less than 5 wt % of latent alcohol that can be used for compounding silica‐filled rubbers is described. The AMS derived from octyl‐triethoxysilane (OTES) behaves as a good shielding agent in silica‐filled rubber to significantly reduce the compound Mooney viscosity and filler flocculation. The co‐AMS prepared from OTES and 3‐mercaptopropyl‐trimethoxysilane yielded an effective shielding and coupling agent for reinforcing the silica‐filled vulcanizates. The alcohols released as volatile organic compounds (VOC) are quantified during compounding and processing along with the compound properties of silica‐filled vulcanizates containing various silicon compounds such as bis‐(triethoxysilyl propyl) disulfide (TESPD), a polyhedral oligomeric silsesquioxanes (POSS), OTES, AMS, or co‐AMS. Dynamic mechanical properties such as dependences of hysteresis on temperature (HTD) and storage modulus on strain (MSD) are discussed. Stronger HTD and weaker MSD were found in stocks containing co‐AMS or a combination of AMS and a coupling agent when compared with that with TESPD. Stronger HTD and weaker MSD may benefit a tire compound with lower rolling resistance, more stable handling performance, as well as better wet traction. More importantly, the VOC released during the manufacture of rubber articles are significantly reduced in stocks containing AMS (or co‐AMS) when compared with those with a silane. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effect of modifiers on morphology and thermal properties of novel thermoplastic polyurethane‐peptized laponite nanocomposite
Authors: Mishra Ananta K. , Chattopadhyay Santanu , Nando Golok B. 
Published: September 2009

AbstractLaponite RDS (Laponite containing pyrophosphate based peptizer) was modified with cetyl trimethyl ammonium bromide (cLS) and dodecylamine hydrochloride (dLS), respectively. Thermoplastic polyurethane (TPU)‐modified Laponite RDS nanocomposites were prepared by solution mixing technique. Morphologies of these two modified clay‐nanocomposites are found to be markedly different. cLS based TPU nanocomposites exhibit partly exfoliated, intercalated, and aggregated structure at lower clay content but a network type of structure is observed at higher clay content. However, dLS based TPU nanocomposites demonstrate spherical cluster type of structure at all clay contents. Nearly two fold increase in storage modulus is observed in both glassy and rubbery state with merely 1% cLS content which gradually decreases with an increase in the clay content. However, in case of dLS filled nanocomposite, gradual increase in storage modulus is observed with an increase in the clay content. Thermogravimetric analysis (TGA) studies indicate that the temperature corresponding to 5 wt % degradation of TPU is enhanced by 19.1 and 12.5°C with the addition of merely 1% cLS and dLS, respectively. However, the activation energy of degradation of neat TPU, as determined by isothermal TGA analysis, is found to be higher than that of the nanocomposites containing 1% of cLS and dLS, respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Ethyl vinyl acetate copolymer—SrAl2O4:Eu,Dy and Sr4Al14O25:Eu,Dy phosphor‐based composites: Preparation and material properties
Authors: Mishra S. B , Mishra A. K. , Luyt A. S. , Revaprasadu N. , Hillie K. T. , vdM Steyn W. J. , Coetsee E. , Swart H. C. 
Published: September 2009

AbstractNew photoactive composite based on ethyl vinyl acetate (EVA) and SrAl2O4:Eu,Dy or Sr4Al14O25:Eu,Dy were prepared by melt mixing or extrusion methodologies. The phosphorescent behavior and material properties of the polymer‐phosphor composites were studied. The morphology of the polymer and the composites were studied by using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X‐ray spectroscopy (EDS). The SEM shows that the physical and chemical behavior of the matrix and the extrusion conditions were primarily responsible for the surface morphology. TEM and EDS show that the phosphor particles were uniformly dispersed in the EVA matrix. A broad band of ultraviolet (UV)‐excited phosphorescence of SrAl2O4:Eu,Dy and Sr4Al14O25:Eu,Dy phosphors and the respective composites were observed at wavelengths of 516 nm and 490 nm, respectively. The photoluminescence (PL) spectra showed less intense phosphorescence but no shift in the wavelength of the emission peak for all the composites. The Hamburg wheel test was done on all the composites and the PL measurements before and after the test showed almost no change in the intensity of the emission. Thermal studies showed that the presence of the phosphors in the matrix slightly increased the crystallinity of EVA, which leads to higher melting enthalpies. Tensile testing shows very little change in the tensile strength and flexibility of the ethylene vinyl acetate copolymer. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Toughened nylon66/nylon6 ternary nanocomposites by elastomers
Authors: Chen Jun , Wu Wei , Chen Chuan , He Sanxiong 
Published: September 2009

AbstractThe elastomer toughening of PA66/PA6 nanocomposites prepared from the organic modified montmorillonite (OMMT) was examined as a means of balancing stiffness/strength versus toughness/ductility. Several different formulations varying in OMMT content were made by mixing of PA6 and OMMT as a master‐batch and then blending it with PA66 and different elastomers in a twin screw extruder. In this sequence, the OMMT layers were well exfoliated in the nylon alloy matrix. The introduction of silicate layers with PA6 induced the appearance of the γ crystal phase in the nanocomposites, which is unstable and seldom appears in PA66 at room temperature and it further affected the morphology and dispersion of rubber phase resulting in much smaller rubber particles. The incorporation of POE‐g‐MA particles toughened the nanocomposites markedly, but the tensile modulus and strength were both reduced. Conversely, the use of OMMT increased the modulus but decreased the fracture toughness. The nanocomposites exhibited balanced stiffness and toughness. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
The copper sulfide coating on polyacrylonitrile with a chelating agent of ethylenediaminetetraacetic acid by an electroless deposition method and its EMI shielding effectiveness
Authors: Chen Yen‐Hung , Huang Chi‐Yuan , Roan Ming‐Lih , Lai Fu‐Der , Chen Kan‐Nan , Yeh Jen‐Taut 
Published: September 2009

AbstractIn this study, a copper sulfide layer was instantaneously coated on the polyacrylonitrile (PAN) by an electroless plating method with the reduction agents NaHSO3 and Na2S2O3·5H2O and a chelating agent (ethylenediaminetetraacetic acid, EDTA). A variety of concentrations of EDTA was added to obtain the anchoring effect and chelating effect in the electroless plating bath. The mechanism of the Cux(x = 1, 2)S growth and the electromagnetic interference shielding effectiveness (EMI SE) of the composite were studied. It was found that the vinyl acetate was residual in PAN substrate would be purged due to the swelling effect by EDTA solution. Then, the anchoring effect occurred due to the hydrogen bonding between the pits of PAN substrate and the chelating agent. Consequently, the copper sulfide layer deposited successfully by the electroless plating reacted upon EDTA. The swelling degree (Sd) was proposed and evaluated from the FTIR spectra. The relationship between swelling degree of the PAN composite and EDTA concentration (C) is expressed as follows: Sd = 0.13 + 0.90 × e(−15.15C). On the other hand, the FESEM micrograph showed that the average thickness of copper sulfide increased from 76 to 383 nm when the concentration of EDTA increased from 0.00 to 0.20M. For this reason, the EMI SE of the composites increased from 10–12 dB to 20–23 dB. The GIA‐XRD and laser Raman analysis indicated that the deposited layer consisted of CuS and Cu2S. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effect of hot drawing on properties of wet‐spun poly(L,D‐lactide) copolymer multifilament fibers
Authors: Rissanen Marja , Puolakka Arja , Hukka Terttu , Ellä Ville , Kellomäki Minna , Nousiainen Pertti 
Published: September 2009

AbstractPolylactide stereocopolymer multifilament fibers were prepared by wet spinning and subsequent hot drawing. The stereocopolymers were poly‐(L,D‐lactide) [P(L,D)LA], L/D ratio 96/4, and poly‐(L,DL‐lactide) [P(L,DL)LA], L/DL ratio 70/30. They were dissolved in dichloromethane and coagulated in a spin bath containing ethanol. The hot‐drawing temperature was 65°C. The draw ratios (DR) were upto 4.5 to the P(L,D)LA 96/4 filaments and upto 3 to the P(L,DL)LA 70/30 filaments. Wet spinning decreased crystallinities of both copolymers. Hot drawing increased the crystallinity of the P(L,D)LA 96/4 filament but not to the level of the original copolymer, whereas the as‐spun and the hot‐drawn P(L,DL)LA 70/30 filaments were amorphous. The filament diameter, tenacity, Young's modulus, and elongation at break were dependent on the DR. The maximum tenacity (285 MPa) and Young's modulus (2.0 GPa) were achieved with the P(L,D)LA 96/4 filament at the DR of 4.5. Respectively, the maximum tenacity of the hot‐drawn P(L,DL)LA 70/30 filament was 175 MPa and Young's modulus 1.3 GPa at the DR of 3. Hot drawing slowed down in vitro degradation rate of both stereocopolymer filaments. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
In vitro release kinetics of bovine serum albumin from highly swellable dextran hydrogels
Authors: İmren Dilek , Gümüşderelioğlu Menemşe , Güner Ali 
Published: September 2009

AbstractHydrogels synthesized from a polysaccharide‐based polymer, dextran, in the presence of two crosslinking agents, N,N′‐methylenebisacrylamide and epichlorohydrin, were evaluated for the oral colon‐specific delivery of polypeptide drugs. These novel dextran hydrogels had significantly greater swelling ratios than recently developed dextran hydrogels. A model protein, bovine serum albumin, was loaded into 50% (by weight) crosslinker‐containing dextran hydrogels in two ways: during the crosslinking reaction and by a soaking method. The loading capacity was varied between 22 and 25 mg/g of dry gel, depending on the loading procedure. In vitro release experiments were performed with a simulated gastrointestinal system in the presence and absence of dextranase. The diffusion exponents were calculated by means of a semiempirical power‐law equation for the release of protein from swellable hydrogel discs. Bovine serum albumin was mainly released by Fickian diffusion, and this indicated that its hydrodynamic diameter (7.7 nm) was smaller than the hydrogel mesh size (∼19 nm). The release of bovine serum albumin from both hydrogel types was substantially higher than expected, especially in the presence of dextranase, and this was attributed to the high swellability of the hydrogels. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Crossflow filtration of iron(III), copper(II), and cadmium(II) aqueous solutions with alginic acid/cellulose composite membranes
Authors: Çifci Cemal , Şanlı Oya 
Published: September 2009

AbstractThe removal of Fe(III), Cu(II), and Cd(II) ions from aqueous solutions was investigated with a crossflow filtration technique. Alginic acid (AA)/cellulose composite membranes were used for retention. In the filtration of Fe(III) solutions, the effects of the crossflow velocity, applied pressure, AA content of the membranes, and pH on the retention percentage and the permeate flux were examined. The maximum retention percentage was found to be 89% for a 1 × 10−4M Fe(III) solution at the flow velocity of 100 mL/min and the pressure of 60 kPa with 0.50% (w/v) AA/cellulose composite membranes at pH 3. Aqueous solutions of Cu(II) and Cd(II) were filtered at the flow velocity of 100 mL/min and pressure of 10 kPa. The effects of the AA content of the membranes and pH of the waste medium on the retention percentage and the permeate flux were determined. For 1 × 10−4M Cu(II) and Cd(II) solutions, the maximum retention percentages were found to be 94 and 75%, respectively, at pH 7 with 0.50% (w/v) AA/cellulose composite membranes. When metal‐ion mixtures were used, the retention percentages of Fe(III), Cu(II), and Cd(II) were found to be 89, 48, and 10%, respectively, at pH 3 with 0.50% (w/v) AA/cellulose composite membranes. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Ferulic acid as a comonomer in the synthesis of a novel polymeric chain with biological properties
Authors: Iemma Francesca , Puoci Francesco , Curcio Manuela , Parisi Ortensia I. , Cirillo Giuseppe , Spizzirri Umile G. , Picci Nevio 
Published: September 2009

AbstractIn this study, ferulic acid was copolymerized with methacrylic acid to obtain a useful material with both antioxidant and antifungal properties. An ascorbic acid/hydrogen peroxide redox pair was used as a water‐soluble and biocompatible initiator system to prime the one‐pot polymerization reaction. The obtained material was characterized with gel permeation chromatography, Fourier transform infrared spectroscopy, ultraviolet spectroscopy, and fluorescence analyses, and the disposable phenolic group content was determined to verify the insertion of ferulic acid into the polymeric backbone. Finally, the antioxidant and antifungal activities were demonstrated toward the hydroxyl radical and Aspergillus niger, respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Enantioselective Protonation of Itaconimides with Thiols and the Rotational Kinetics of the Axially Chiral CN Bond
Authors: Lin Shishi , Leow Dasheng , Huang Kuo‐Wei , Tan Choon‐Hong 
Published: September 2009

AbstractBicyclic guanidines are able to catalyze the protonation reactions of 2‐phthalimidoacrylates with thiols in excellent yields and enantioselectivities. The protonation reaction of itaconimides with secondary phosphine oxides is also known. Herein, the tandem conjugate addition–enantioselective protonation ofN‐substituted itaconimides with thiols catalyzed by chiral bicyclic guanidine is investigated. The rotational barrier of the CN axis ofN‐2‐tert‐butyl phenylitaconimide is also studied, both experimentally and computationally.
Comparative gene expression of intestinal metabolizing enzymes
Authors: Shin Ho‐Chul , Kim Hye‐Ryoung , Cho Hee‐Jung , Yi Hee , Cho Soo‐Min , Lee Dong‐Goo , Abd El‐Aty A. M. , Kim Jin‐Suk , Sun Duxin , Amidon Gordon L. 
Published: September 2009

AbstractThe purpose of this study was to compare the expression profiles of drug‐metabolizing enzymes in the intestine of mouse, rat and human. Total RNA was isolated from the duodenum and the mRNA expression was measured using Affymetrix GeneChip oligonucleotide arrays. Detected genes from the intestine of mouse, rat and human were ca. 60% of 22690 sequences, 40% of 8739 and 47% of 12559, respectively. Total genes of metabolizing enzymes subjected in this study were 95, 33 and 68 genes in mouse, rat and human, respectively. Of phase I enzymes, the mouse exhibited abundant gene expressions for Cyp3a25, Cyp4v3, Cyp2d26, followed by Cyp2b20, Cyp2c65 and Cyp4f14, whereas, the rat showed higher expression profiles of Cyp3a9, Cyp2b19, Cyp4f1, Cyp17a1, Cyp2d18, Cyp27a1 and Cyp4f6. However, the highly expressed P450 enzymes were CYP3A4, CYP3A5, CYP4F3, CYP2C18, CYP2C9, CYP2D6, CYP3A7, CYP11B1 and CYP2B6 in the human. For phase II enzymes, glucuronosyltransferase Ugt1a6, glutathione S‐transferases Gstp1, Gstm3 and Gsta2, sulfotransferase Sult1b1 and acyltransferase Dgat1 were highly expressed in the mouse. The rat revealed predominant expression of glucuronosyltransferases Ugt1a1 and Ugt1a7, sulfotransferase Sult1b1, acetyltransferase Dlat and acyltransferase Dgat1. On the other hand, in human, glucuronosyltransferases UGT2B15 and UGT2B17, glutathione S‐transferases MGST3, GSTP1, GSTA2 and GSTM4, sulfotransferases ST1A3 and SULT1A2, acetyltransferases SAT1 and CRAT, and acyltransferase AGPAT2 were dominantly detected. Therefore, current data indicated substantial interspecies differences in the pattern of intestinal gene expression both for P450 enzymes and phase II drug‐metabolizing enzymes. This genomic database is expected to improve our understanding of interspecies variations in estimating intestinal prehepatic clearance of oral drugs. Copyright © 2009 John Wiley & Sons, Ltd.
Arsenate‐induced apoptosis in murine embryonic maxillary mesenchymal cells via mitochondrial‐mediated oxidative injury
Authors: Singh Saurabh , Greene Robert M. , Pisano M. Michele 
Published: September 2009

AbstractBACKGROUND: Arsenic is a ubiquitous element that is a potential carcinogen and teratogen and can cause adverse developmental outcomes. Arsenic exerts its toxic effects through the generation of reactive oxygen species (ROS) that include hydrogen peroxide (H2O2), superoxide‐derived hydroxyl ion, and peroxyl radicals. However, the molecular mechanisms by which arsenic induces cytotoxicity in murine embryonic maxillary mesenchymal (MEMM) cells are undefined. METHODS: MEMM cells in culture were treated with different concentrations of pentavalent sodium arsenate [As (V)] for 24 or 48 hr and various end points measured. RESULTS: Treatment of MEMM cells with the pentavalent form of inorganic arsenic resulted in caspase‐mediated apoptosis, accompanied by generation of ROS and disruption of mitochondrial membrane potential. Treatment with caspase inhibitors markedly blocked apoptosis. In addition, the free radical scavenger N‐acetylcysteine dramatically attenuated arsenic‐mediated ROS production and apoptosis, and exposure to arsenate increased Bax and decreased Bcl protein levels in MEMM cells. CONCLUSIONS: Taken together, these findings suggest that in MEMM cells arsenate‐mediated oxidative injury acts as an early and upstream initiator of the cell death cascade, triggering cytotoxicity, mitochondrial dysfunction, altered Bcl/Bax protein ratios, and activation of caspase‐9. Birth Defects Research (Part A), 2010. © 2009 Wiley‐Liss, Inc.