bluuebunny/crossref_metadata_2025_split huggingface dataset:
Unique aerodynamically driven methodology for forming droplets, threads to scaffolds
Authors: Arumuganathar S. , Jayasinghe S. N. , Suter N. 
Published: March 2007

AbstractJet‐based methodologies for forming droplets and threads leading to the fabrication of scaffolds are playing a pivotal role in materials science and engineering. These techniques are essentially interfacing engineering with the biological sciences. There are several routes for forming droplets, which are subsequently deposited with precision, namely, ink‐jet printing to electrospraying. Fabricating threads/fibers sized from the nano‐ to the micrometer range are generally carried out by means of electrospinning. These three processes are well‐established and have been explored to a great extend. In this article, we have shown a unique processing technology completely driven by a pressure difference over an orifice possessing the ability to form droplets, threads to scaffolds. Hence, this process now joins the microfabrication race alongside its competing technologies, in the hope to undergo a rapid developmental program arming itself for competing with its rival technologies. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3844–3848, 2007
Nonisothermal cure kinetics of diglycidylether of bisphenol‐A/amine system reinforced with nanosilica particles
Authors: Ghaemy M. , Nasab S. M. Amini , Barghamadi M. 
Published: March 2007

AbstractEpoxy‐silica nanocomposites were obtained from directly blending diglycidylether of bisphenol‐A (DGEBA)‐based epoxy and nanoscale silica (NS) and then curing with 4,4′‐diaminodiphenylamine (DDA). The effect of amount of nanosilica (NS) particles as catalyst on the mechanism and kinetic parameters of cure reaction of DGEBA/DDA system was studied. The kinetics parameters were obtained from nonisothermal differential scanning calorimeter (DSC) data using the Kissinger and Ozawa equations. The exothermic peak was shifted toward lower temperatures in DGEBA/DDA/NS system with increasing the amount of nanoslica particles. However, the existence of NS particles with hydroxyl groups in the structure in the mixture of DGEBA/DDA catalyzes the cure reaction and increases the rate constant. The activation energy of cure reaction of DGEBA/DDA system obtained from two methods were in good agreement, and showed a decrease when NS particles were present in the mixture. The mechanism of reaction of DGEBA with DDA was carried out by isothermal curing in the oven at 130°C and measuring the disappearance peak of epoxide group at 916 cm−1 using FTIR. The diffusive behavior of two systems was investigated during water sorption at 25°C and the experimental results fitted well to Fick's law. Diffusion coefficient of cured sample from DGEBA/DDA/10% NS blend decreased in comparison with the sample without NS particles. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3855–3863, 2007
Diffusivity of ethylene and propylene in atactic and isotactic polypropylene: Morphology effects and free‐volume simulations
Authors: Gonzalez A. , Eceolaza S. , Etxeberria A. , Iruin J. J. 
Published: March 2007

AbstractDiffusion coefficients of propylene and ethylene through particles and films of isotactic polypropylene (iPP) as well as through films of atactic, completely amorphous, polypropylene have been measured by gravimetric experiments. iPP particles with relatively similar crystallinities but with different particle size distributions (PSD), and different origins have been used. They exhibited very different diffusion coefficients when the average radius of the PSD was used as the dimensional parameter of the diffusion process. However, films prepared with these particles and having similar crystallinities provided similar diffusion coefficients. The results are consistent with the idea of a multigrain structure in the particles, where the apparent (or experimental) diffusion coefficient is a consequence of the complex system formed by internal and external areas. The diffusion coefficient of the films, taken as the real diffusion magnitude, can be used in the calculation of the true diffusional radius of these multigrain particles. Experimental results of the diffusion coefficients have been reasonably well reproduced with the aid of the Vrentas‐Duda free volume model. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3871–3878, 2007
Effect of dispersion state of organoclay on cellular foam structure and mechanical properties of ethylene vinyl acetate copolymer/ethylene‐1‐butenecopolymer/organoclay nanocomposite foams
Authors: Park Keun‐Wan , Ray Chowdhury Subhendu , Park Cha‐Cheol , Kim Gue‐Hyun 
Published: March 2007

AbstractIn this study, our goal is to obtain lower density of ethylene‐vinyl acetate copolymer (EVA)/ethylene‐1‐butene copolymer (EtBC) foams without sacrificing mechanical properties. For this purpose EVA/EtBC/organoclay (Cloisite 15A, Closite 30B) nanocomposite foams were prepared. To investigate the effect of compatibilizer on the dispersion state of organoclay in cellular foam structure and mechanical properties of the EVA/EtBC/organoclay foams composites were prepared with and without maleic anhydride grafted EtBC (EtBC‐g‐MAH). The dispersion of organoclay in EVA/EtBC/organocaly foams was investigated by X‐ray diffraction and transmission electron microscopy. The EVA/EtBC nanocomposite foamswith the compatibilzer, especially EVA/EtBC/Cloisite 15A/EtBC‐g‐MAH foams displayed more uniform dispersion of organoclay than EVA/EtBC nanocomposite foams without the compatibilzer. As a result, EVA/EtBC/Cloisite 15A/EtBC‐g‐MAH foams have the smallest average cell size and highest 100% tensile modulus followed by EVA/EtBC/Cloisite 30B/EtBC‐g‐MAH foams. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3879–3885, 2007
Properties of dynamically vulcanized ethylene–propylene–diene copolymer/polypropylene blends
Authors: Taşdemir Münir , Topsakaloğlu Murat 
Published: March 2007

AbstractIn this study, vulcanized thermoplastic elastomers were produced through the formation of crosslinks with peroxide for different ratios of ethylene–propylene–diene copolymer to polypropylene. Mixing was performed with a twin‐screw extruder. Afterward, the yield, tensile strength, elastic modulus, elongation, Izod impact strength, hardness, melt flow index, Vicat softening point, heat deflection temperature, and density of the crosslinks were determined. The thermal transition temperatures and microstructure were determined with differential scanning calorimetry and scanning electron microscopy, respectively. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3895–3902, 2007
Effect of ionomer on clay dispersions in polypropylene‐layered silicate nanocomposites
Authors: Liu Hongzhi , Tag Lim Hyung , Hyun Ahn Kyung , Jong Lee Seung 
Published: March 2007

AbstractIn this study, polypropylene (PP)/clay nanocomposites containing different concentrations of ethylene‐methacrylic acid ionomer (i.e. Surlyn®) were prepared, and the effect of ionomer on clay dispersion was studied via WAXD, rheology, SEM, and TEM. The role of the ionomer in the nanocomposites was compared with that of maleic anhydride grafted PP (PP‐g‐MA), which has been widely used as a compatibilizer in making PP/clay nanocomposites. With an increase in the concentration of compatibilizer, the position of d001 peak of OMMT shifted toward a lower angle for PP‐g‐MA system, while the position remained almost unchanged for Surlyn system, in which a larger interlayer spacing (d001) was found with respect to the former. In rheology, the addition of the ionomer led to a gradual increase in both moduli and complex viscosity, and the nonterminal behavior at low frequency was observed in both systems. In addition, the ternary hybrid containing 20 wt % Surlyn achieved the largest enhancement in relative viscosity, which was more than that of the nanocomposite prepared from pure Surlyn or pure PP, presumably indicative of the existence of strong interaction between the components. Finally, SEM and TEM micrographs demonstrated that exfoliated structure was preferred for PP/Surlyn/OMMT hybrids, while intercalated morphology for PP/PP‐g‐MA/OMMT. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 4024–4034, 2007
Preparation and properties of iodine‐doped radiopaque natural rubber
Authors: Nisha V. S , Rani Joseph  
Published: March 2007

AbstractPolymers exhibit low electron density and they are radiolucent. Polymers can be made radiopaque by different techniques. We report a method for the preparation of radiopaque material from natural rubber (NR). NR in its latex form was iodinated. Iodinated natural rubber (INR) was characterized by using UV, thermo gravimetric analysis (TGA), and X‐ray images. INR was compounded at high and low temperatures and its physical properties were measured. The low temperature cured samples show good radiopacity and conductivity. The optical density of low temperature cured samples was measured. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Allylated novolac/4,4′‐bismaleimidodiphenylmethane resin containing polyhedral oligomeric silsesquioxane: Preparation, morphology and thermal stability
Authors: Li Wanwan , Liu Feng , Wei Liuhe , Zhao Tong 
Published: March 2007

AbstractAllylated novolac/4,4′‐bismaleimidodiphenylmethane resin (AN/BDM) had been modified with well‐defined inorganic building blocks‐polyhedral oligomeric silsesquioxane (POSS). Octamaleimidophenyl polyhedral silsesquioxane (OMPS) was used as the cocuring reagent of the AN/BDM resin to prepare POSS‐modified AN/BDM resin, and POSS content was between 0 and 17.8 wt %. The curing reaction of the POSS‐modified AN/BDM resin was monitored by means of Fourier transform infrared spectroscopy (FTIR), and the results revealed that maleimide groups on OMPS molecule could undergothe curing reaction between allyl groups and maleimide groups. Therefore, the crosslinked network containing POSS was formed. Scanning electron microscopy (SEM) and X‐ray diffraction (XRD) were employed to study the morphology of the cured POSS‐modified AN/BDM resins. The homogeneous dispersion of POSS cages in AN/BDM matrices was evidenced. Thermogravimetric analysis (TGA) indicated that incorporation of POSS into AN/BDM crosslinked network led to enhanced thermal stability. The improved thermal stability could be ascribed to higher crosslink density and inorganic nature of POSS. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3903–3908, 2007
Effect of polymer–clay interaction on solvent transport behavior of fluoroelastomer–clay nanocomposites and prediction of aspect ratio of nanoclay
Authors: Maiti Madhuchhanda , Bhowmick Anil K. 
Published: March 2007

AbstractDiffusion and sorption of methyl ethyl ketone and tetrahydrofuran through fluoroelastomer‐clay nanocomposites were investigated in the temperature range of 30–60°C by swelling experiments. Slightly non‐Fickian transport behavior was found for these nanocomposites, having variation of type of nanoclay and loading. Different transport parameters depend on the size and shape of the penetrant molecules. The results were used to study the effect of nanoclay on the solvent transport‐properties of nanocomposites and their interactions with solvents. The diffusion coefficient of methyl ethyl ketone at 30°C for neat rubber was 1.43 × 10−8 cm2 s−1, while those of the unmodified and the modified clay filled samples at 4 phr loading were 0.24 × 10−8 and 0.50 × 10−8 cm2 s−1, respectively. At 8 and 16 phr loading of the unmodified clay, it was found to be 0.44 × 10−8 and 0.64 × 10−8 cm2 s−1, respectively. The samples were also reswelled after deswelling. Surprisingly, transport behavior became Fickian on reswelling. Interestingly, ratio of diffusion coefficients of the filled system to the neat system was found to be almost same for the first time swelling and reswelling experiments. The results showed that better polymer‐clay interaction in the case of the unmodified‐clay filled nanocomposites is responsible for enhanced solvent‐resistance property. From the permeation data, for the first time, aspect ratio of nanoclays in different composites was calculated and found to have good correlation with the morphology data obtained from transmission electron microscopy. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Physical properties of water‐blown rigid polyurethane foams from vegetable oil‐based polyols
Authors: Tu Yuan‐Chan , Kiatsimkul Pimphan , Suppes Galen , Hsieh Fu‐Hung 
Published: March 2007

AbstractFifty vegetable oil‐based polyols were characterized in terms of their hydroxyl number and their potential of replacing up to 50% of the petroleum‐based polyol in waterborne rigid polyurethane foam applications was evaluated. Polyurethane foams were prepared by reacting isocyanates with polyols containing 50% of vegetable oil‐based polyols and 50% of petroleum‐based polyol and their thermal conductivity, density, and compressive strength were determined. The vegetable oil‐based polyols included epoxidized soybean oil reacted with acetol, commercial soybean oil polyols (soyoils), polyols derived from epoxidized soybean oil and diglycerides, etc. Most of the foams made with polyols containing 50% of vegetable oil‐based polyols were inferior to foams made from 100% petroleum‐based polyol. However, foams made with polyols containing 50% hydroxy soybean oil, epoxidized soybean oil reacted with acetol, and oxidized epoxidized diglyceride of soybean oil not only had superior thermal conductivity, but also better density and compressive strength properties than had foams made from 100% petroleum polyol. Although the epoxidized soybean oil did not have any hydroxyl functional group to react with isocyanate, when used in 50 : 50 blend with the petroleum‐based polyol the resulting polyurethane foams had density versus compressive properties similar to polyurethane foams made from 100% petroleum‐based polyol. The density and compressive strength of foams were affected by the hydroxyl number of polyols, but the thermal conductivity of foams was not. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Characterization and property correlations of amorphous poly(alpha olefin)
Authors: Soo Ha Hyun , Hwan Shin Jung , Kyu Kim Byung 
Published: March 2007

AbstractAmorphous poly(alpha olefins)® (APAOs) with various types and contents of comonomers, and molecular weight were characterized by general, thermal, rheological, and mechanical methods and their properties were correlated with their molecular parameters. It was found that they can be used as a modifier for isotactic polypropylene. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Transesterification reaction between acetylated wood and trialkoxysilane coupling agents
Authors: Özmen Nilgül , Sami Çetin Nihat , Tingaut Philippe , Sèbe Gilles 
Published: March 2007

AbstractA novel dibutyltin oxide‐catalyzed transesterification reaction between acetylated maritime pine sapwood (Pinus pinaster Soland) and methyltrimethoxysilane (MTMS) was studied. The transesterification exchange between the acetyl moities and MTMS was confirmed by weight percent gain calculations, Fourier‐transform infrared spectroscopy, as well as solid state 13C and 29Si crosspolarization with magic‐angle spinning nuclear magnetic resonance spectroscopy. The silicon atoms in the MTMS‐transesterified wood were found to exist in the form of more or less condensed structures, concurrently formed by condensation between neighboring Si(OMe)3 groups. An increase in the acetyl/MTMS exchange rate was also noted when the catalyst amount, temperature, or reaction time were increased. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Microcellular foaming of PE/PP blends
Authors: Zhang Ping , Zhou Nan Qiao , Wu Qing Feng , Wang Ming Yi , Peng Xiang Fang 
Published: March 2007

AbstractThree different polyethylene/polypropylene (PE/PP) blends were microcellular foamed and their crystallinities and melt strengths were investigated. The relationship between crystallinity, melt strength, and cellular structure was studied. Experimental results showed that the three blends had similar variation patterns in respect of crystallinity, melt strength, and cellular structure, and these variation patterns were correlative for each blend. For all blends, the melt strength and PP melting point initially heightened and then lowered, the PP crystallinity first decreased, and then increased as the PE content increased. At PE content of 30%, the melt strength and PP melting point were highest and the PP crystallinity was least. The blend with lower PP crystallinity and higher melt strength had better cellular structure and broader microcellular foaming temperature range. So, three blends had best cellular structure at PE content of 30%. Furthermore, when compared with PE/homopolymer (hPP) blend, the PE/copolymer PP (cPP) blend had higher melt strength, better cellular structure, and wider microcellular foaming temperature range, so it was more suited to be microcellular foamed. Whereas LDPE/cPP blend had the broadest microcellular foaming temperature range because of its highest melt strength within three blends. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 4149–4159, 2007
Compositions based on aromatic polycarbonate and metallic phosphinic acids
Authors: Ozden S. , Shaov A. H. , Charayev A. 
Published: March 2007

AbstractFour different polymer stabilizers were synthesized from the salt derivatives of phosphinic acids (p‐butoxyphenylcyclohexyl‐phosphinic acid) and potassium, nickel, and two different grades of iron metals. The synthesized stabilizers were introduced into an industrial polycarbonate (PC) and their effects on the mechanical and thermal behavior of PC were investigated. The experiments were carried on following the introduction of the stabilizer into the polymer. The mechanical properties were sensitive to the amount of the stabilizer. Small amounts of potassium increased the breaking stress, the modulus of elasticity, and elongation at break of PC. On the other hand, nickel and iron increased the modulus of elasticity and decreased the breaking stress and elongation at break. The additives negatively affected the thermal properties. This deterioration was caused by the increase of molecular distance between the chains that led to the reduction of polar forces and increased the free volume of the polymer. Heat treatment increased the brittleness and reduced the breaking strength, ductility, and modulus of elasticity of modified PC. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3628–3636, 2007
Novel tin‐coupled star‐shaped medium vinyl butadiene rubber. I. Arm number and its effect on properties
Authors: Lu Jianmin , Zhang Xingying , Zhao Suhe , Yang Wantai 
Published: March 2007

AbstractTo achieve low rolling resistance, high wet grip, and favorable overall performance, star‐shaped medium vinyl butadiene rubber (S‐MVBR) was designed and prepared by “core‐first” method, where novel multifunctional organolithium containing Sn atom as initiator, THF as structure regulator, and carbon–hydrogen compound as solvent. The results showed that coupling reaction between SnCl4 and dilithium is stoichiometrical, and this method has much higher efficiency than the “arm‐first” method. When dilithium is composed of 4–10 repeating units, the average arm number of S‐MVBR is conveniently controlled between 3 and 5 by initiator functionality, which can be easily regulated by the mole ratio of active lithium of dilithium short chain to Cl− in SnCl4. As Sn coupling decreases numbers of noncrosslinking free ends, S‐MVBR has lower rolling resistance, dynamic heating and higher wet grip than linear MVBR. Meanwhile, mechanical properties and processing properties are improved. And the formation of multiarm structure has little effect on viscosity. S‐MVBR with arm number of 3.8 has optimal overall performance. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3917–3923, 2007
Studies on UV‐stable silicone–epoxy resins
Authors: Huang Wei , Zhang Ying , Yu Yunzhao , Yuan Youxue 
Published: March 2007

AbstractSilicone–epoxy resins were synthesized through hydrosilylation of 1,2‐epoxy‐4‐vinyl‐cyclohexane with 1,3,5,7‐tetramethycyclotetrasiloxane. The silicone–epoxy resins showed high reactivity in the presence of aluminum complex/silanol compound catalysts. Curing of the resins was effected at extremely low concentrations of the aluminum acetylacetonate/Ph2Si(OH)2 catalyst to give hard materials with optical clarity. For the silicone–epoxy resins containing SiH bonds, Al(acac)3 alone is effective for the curing. The cured silicone–epoxy resins showed excellent UV resistance. An improvement in the lifetime of UV‐LEDs was achieved using the silicone–epoxy compositions as encapsulant. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3954–3959, 2007
Synthesis and transport abilities of new membrane materials incorporating bipyrazolic tripods
Authors: Malek Fouad , Ramdani Abdelkrim , Zidane Ismail , Radi Smaail 
Published: March 2007

AbstractMembrane materials were obtained by photopolymerization reaction of formulation spread over a polyacrylonitrile (PAN) support. The formulation contains the active bipyrazolic tripods monomers, the styrene, and the photostart. The facilitated transport and the extraction power of Cd(II), Pb(II), and Hg(II) through the synthesized membranes were reported. We have determined both the diffusion flux F of different cations and the selectivity S of the prepared membranes towards each cations. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104, 3967–3972, 2007
Blends of thermoplastic polyurethane and polypropylene. I. Mechanical and phase behavior
Authors: Bajsić Emi Govorčin , Šmit Ivan , Leskovac Mirela 
Published: March 2007

AbstractPure thermoplastic polyurethane (TPU), polypropylene (PP), and TPU/PP blends with different weight ratios prepared in a twin‐screw extruder were investigated by dynamic mechanical analysis (DMA), the universal tester for mechanical investigation, and by wide‐angle X‐ray diffraction (WAXD). The addition of PP above 20 wt % to the TPU stepwise changed the ductility and Young's modulus, i.e., apparently a kind of ductile → brittle transition occurred between TPU/PP 80/20 and TPU/PP 60/40 blends. This fact and the result of analysis of WAXD curves indicated matrix → dispersed phase inversion in this concentration region. TPU melt enabled easier migration of the PP chains and prolonged crystallization of PP matrix during solidification process affecting thus crystallite size, orientation, and crystallinity. In accordance to this fact, DMA results indicated partial miscibility of PP with polyurethane in the TPU/PP blends due to the lack of interfacial interaction and adhesion between the nonpolar crystalline PP and polar TPU phases. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104, 3980–3985, 2007