bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hybrid organic/inorganic dendritic triblock copolymers: Synthesis, nanostructure characterization, and micellar behavior
Authors: Namazi Hassan , Jafarirad Saeed 
Published: March 2010

AbstractA new class of amphiphilic dendritic ABA triblock copolymers, which is based on organic linear polyethylene oxide (PEO) and inorganic dendritic carbosiloxane (CSO) was synthesized. The strategy used in synthesizing these materials is based on divergent method using hydrosilylation‐alcoholysis cycles. The reaction conditions and structural features of dendrimers were analyzed by different physicochemical techniques such as: GPC, NMR, UV spectroscopy, DSC, and viscometry. The generational limit of dendrimer after the first generation, OSC‐D‐PEO‐D‐CSO, forced us to employ HSiCl2CH3 as branching reagent. Also further hydrosilylation of the third generation yielded an irregular structure species. Self‐assembling and morphological studies of first, OSC‐D‐PEO‐D‐CSO, and second, OSC‐D‐PEO‐D‐CSO, generations in aqueous medium were monitored by using fluorescence, TEM and DLS techniques. However, the dendritic block copolymer with third generation, OSC‐D‐PEO‐D‐CSO, could not be dispersed in aqueous phase. The diameters of denderitic micelles had a narrow distribution in the ranges of 69 and 88 nm, respectively. Although the micelles were stable even in first generation, partition equilibrium constants of pyrene and critical micelle concentration in both of dendritic micelles imply that the micellar behaviors of the supramolecules strongly depend on the hydrophobic block's size in which increasing generation effectively promoted the micelle formation. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Solubility profiles of poly(ethylene glycol)/solvent systems. II. comparison of thermodynamic parameters from viscosity measurements
Authors: Di̇nç Cemile Özdemir , Ki̇barer Günay , Güner Ali 
Published: March 2010

AbstractSolution thermodynamics of PEG samples in aqueous and nonaqueous (methanol, chloroform, tetrahydrofuran, and dimethylsulfoxide) solutions have been investigated by viscometric studies at 25, 30, 35, and 40°C. The hydrodynamic expansion factor, ah, and the unperturbed root mean square end‐to‐end distance, $ \langle r^{2}\rangle_\theta^{1/2} $, found for the system indicated that the polymer coils contract as the temperature is raised. The long‐range interaction parameter, B, was also evaluated and a significant decrease with increasing temperature was observed. The theta temperatures, θ, obtained from the temperature dependence of (1/2 − χ) and the second virial coefficient, A2, are quite good in agreement with the calculated values evaluated via extrapolation and interpolation methods. The thermodynamic interaction parameter, χ, was evaluated through the sum of the individual values of enthalpy and entropy dilution parameters for PEG samples. The restrictions applying to the establishment of concentration regimes, short‐range, and long‐range interactions are discussed. A parallelism is found between solubility profiles obtained by solution viscometry and solubility parameter approaches for PEG/solvent systems. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Extraordinary swelling behavior of poly(AMPS) organogel in solvent/DMSO binary mixed media
Authors: Zohuriaan‐Mehr M. J. , Kabiri K. , Kheirabadi M. 
Published: March 2010

AbstractThe present article deals with super‐swelling behavior of crosslinked homopolymer of 2‐acrylamido‐2‐methylpropane sulfonic acid, poly(AMPS), in binary mixtures of dimethyl sulfoxide (DMSO) and various polar solvents including water, mono‐, and polyhydric alcohols, and amide solvents such as N‐methyl pyrrolidone. Extraordinary phase transition sequences including a new unusual swelling phenomenon, referred to as “overentrant” swelling, was observed for this polymeric organogel in the solvent/DMSO mixtures. The swelling behaviors were preliminarily explained based on the major interactions involved in the solvation process and dielectric constant of the swelling media. It was established that the “overentrant” region of the swelling profiles was progressed with the increase of dielectric constant of the mixed solvent media. The overentrant region was disappeared with partial replacement of AMPS units with acrylic acid. This was taken as an additional practical evidence for a major role of the sulfonic acid as the main interactive group involved in the solvation process. The unusual phase transitions were also explained via a semiquantitative approach based on the Gutmann's acceptor number and donor number values to emphasis on the key effect of dissociation degree of the sulfonic acid group (as a function of the solvent type and composition) on the swelling behaviors. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Surface properties of lithospermum‐containing multiple phase emulsion systems
Authors: Tsai Chi , Lin Li‐Huei , Wu Chin‐Sheng , Kwan Chang‐Chin 
Published: March 2010

AbstractIn this study, we employed a one‐step emulsion process—rather than the traditional, relatively difficult two‐step process—to obtain multiple phase emulsion systems containing the Chinese herbal medicine lithospermum. We characterized these systems in terms of their contact angles, surface tensions, fluorescence, and stability and analyzed them using polarized microscopy, atomic force microscopy, and attenuated total reflection Fourier transform infrared spectroscopy. Our one‐step emulsion process involved mixing lithospermum at various concentrations with three different emulsifiers to control the properties of the emulsion systems. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Preparation and properties of glass cloth‐reinforced polyimide composites with improved impact toughness for microelectronics packaging substrates
Authors: Xu Hong‐Yan , Yang Hai‐Xia , Tao Li‐Ming , Fan Lin , Yang Shi‐Yong 
Published: March 2010

AbstractA series of glass cloth‐reinforced thermosetting polyimide composites (EG/HTPI) were prepared from E‐glass cloth (EG) and polyimide matrix resins. The polyimide resins were derived from 1,4‐bis(4‐amino‐2‐ trifluoromethyl‐phenoxy)benzene, p‐phenylenediamine, diethyl ester of 3,3′,4,4′‐benzophenonetetracarboxylic acid, and monoethyl ester of cis‐5‐norbornene‐endo‐2,3‐dicarboxylic acid. Based on the rheological properties of the B‐staged polyimide resins, the optimized molding cycles were designed to fabricate the EG/HTPI laminates and the copper‐clad laminates (Cu/EG/HTPI). Experimental results indicated that the EG/HTPI composites exhibited high thermal stability and outstanding mechanical properties. They had flexural strength of >534 MPa, flexural modulus of >20.0 GPa, and impact toughness of >46.9 kJ/m2. The EG/HTPI composites also showed good electrical and dielectric properties. Moreover, the EG/HTPI laminates exhibited peel strength of ∼ 1.2 N/mm and great isothermal stability at 288°C for 60 min, showing good potential for application in high density packaging substrates. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Interaction of vulcanization and reinforcement of CB on dynamic property of NR characterized by RPA2000
Authors: Zhao Fei , Shi Xinyan , Chen Xiang , Zhao Shugao 
Published: March 2010

AbstractVulcanization and reinforcement are two most important approaches to improve rubber properties. Effect of carbon black (CB) load level on curing process and properties of Natural rubber (NR) compounds and vulcanizates and interaction between vulcanization and reinforcement were characterized by Rubber Processing Analyzer (RPA2000). The incorporation of CB shortened the scorch delay time and prolonged curing time. Only after CB loading level reached about 20 phr, could effective CB network be formed that contributed to the formation of “Payne effect.” Dynamic elastic shear modulus G′ of filled NR compounds had a stronger dependence on strain than that of unfilled NR. There was a synergism between vulcanization and reinforcement on the improvement of shear modulus of NR compounds and vulcanizates. The elastic recovery of vulcanizates restricted the break of CB network through the rubber bridges formed between CB particles and helped the reformation of broken CB network. All these action amplified the reinforcement of CB. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Nonisothermal crystallization kinetics of polytetrafluoroethylene/solid glass microsphere composites
Authors: Wang Zhi‐Chao , Kou Kai‐Chang , Chao Min , Bi Hui , Yan Lu‐Ke 
Published: March 2010

AbstractThe nonisothermal crystallization behavior and kinetics of polytetrafluoroethylene (PTFE) and PTFE/solid glass microsphere (SGM) composites were investigated with differential scanning calorimetry at various cooling rates (ϕ's). Three methods, namely, the Jeziorny, Ozawa and Mo methods, were used to describe the nonisothermal crystallization process. The results show that the peak temperature, crystallinity (Xc), and crystallization half‐time were strongly dependent on the content of SGMs and ϕ. The SGMs in the PTFE/SGM composites exhibited a higher nucleation activity. The nonisothermal crystallization kinetics of PTFE and the PTFE/SGM composites was analyzed successfully with the Jeziorny and Mo methods; however, the Ozawa equation was invalid for the nonisothermal crystallization process. The crystallization activation energy determined with the Kissinger equation was remarkably lower when a small amount of SGMs (5%) was added and then gradually increased and finally became slightly lower than that of pure PTFE as the content of SGMs increased up to 25% in the composites. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Nitroalcohol induced hydrogel formation in amine‐functionalized polymers
Authors: Solomon Marissa R. , O'Connor Naphtali A. , Paik David C. , Turro Nicholas J. 
Published: March 2010

AbstractCertain β‐nitroalcohols degrade under basic conditions or upon heating to form formaldehyde. This reaction provides an elegant approach to generate formaldehyde within a system at a desired time using the stimulus of pH or temperature. Using β‐nitroalcohols as a delivery agent for formaldehyde, polymer crosslinking can be induced via stimulus. Such an approach is akin to those used to prepare “self‐healing” polymers, which have received much attention recently. Herein, we describe the use of certain β‐nitroalcohols as a masked formaldehyde delivery system and demonstrate its use as a crosslinking agent of amine functionalized polymers to form hydrogels. We examine the temperature and pH dependence of 2‐nitro‐1,3‐propanediol and 2‐(hydroxymethyl)‐2‐nitro‐1,2‐propanediol on the rate and extent of gelation and characterize the resulting gel by swelling and FTIR experiments. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Flame‐retardant properties of soybean fabric modified with N‐methylol diakyl phosphonopropionamide
Authors: Vynias D 
Published: March 2010

AbstractSoybean is a competitive production material for fibers as it is abundant and cost effective. However, an inherent deficiency of soybean fiber is its poor flame‐retardant performance. In this study, the effect of N‐methylol diakyl phosphonopropionamide (Pyrovatex CP) on the flame retardancy of soybean was investigated by the Limiting Oxygen Index (L.O.I.) and the vertical flammability test. Little benefit with regard to flame retardancy was found when soybean was treated with Pyrovatex CP in the absence of additives. However, the incorporation of Lyofix MLF in the finishing treatment (3% w/v) increased the L.O.I. values of soybean fiber and enhanced char formation as indicated by Thermogravimetric Analysis (TGA). Improved fastness to washing was observed at higher application levels of Lyofix MLF (6% w/v). X‐ray Photoelectron Spectroscopy (XPS) indicated that surface phosphorus (% atomic) was reduced following washing for all fabrics examined. In addition, the substantivity of Lyofix MLF to soybean surface was exhibited. The flame‐retardant treatment presented in this article is cost effective and results in wash‐durable flame‐retardant fabrics. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effects of the vibration parameters of a hydraulic, dynamic injection‐molding machine on the properties of low‐density polyethylene samples in a plasticating process
Authors: Wang Quan , Qu Jinping 
Published: March 2010

AbstractA novel, self‐made, hydraulic, and dynamic injection‐molding machine was used to mold low‐density polyethylene samples in a standard sample mold. These samples were tested for tensile strength, density, differential scanning calorimetry, and energy consumption of the molding process to explore the influences of the vibration frequency and amplitude on the properties of the products. The results show that the maximum tensile strength was enhanced by 6.1%, the density was higher by 0.34%, the melting point moved to a higher temperature by 1.7°C, and the power consumption of the whole molding process was lowered by 7.5% when the vibration was imposed. The changing regularity is presented. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effects of dilution and charge trapping on the performance of a light‐emitting diode of poly(9‐vinylcarbazole) doped with poly[2‐methoxy‐5‐(2′‐ethyl hexyloxy)– 1,4‐phenylene vinylene]
Authors: Zhang Xinwen , Wu Zhaoxin , Wang Dongdong , Wang Dawei , Hou Xun 
Published: March 2010

AbstractWe report the electroluminescence (EL) enhancement of polymer light‐emitting diodes made by the dispersion of poly[2‐methoxy‐5‐(2′‐ethyl hexyloxy)–1,4‐phenylene vinylene] (MEH–PPV) into poly(9‐vinylcarbazole) (PVK). From the photoluminescence and EL spectra of the polymer blend films, we found that, because of the dilution effect, interchain interactions in MEH–PPV were reduced markedly. The EL spectrum indicated that the charge‐trapping effect contributed to the formation of excitons at the MEH–PPV centers and, thus, strongly enhanced EL. Because of the balance between increasing trapping centers and suppressing interchain interactions, the best device performance was achieved when the polymer blend contained 12% MEH–PPV and 88% PVK (weight ratio), and this also led to improved color purity of the polymer blend devices. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effects of organically modified nanoclay on the transport properties and electrochemical performance of acid‐doped polybenzimidazole membranes
Authors: Hasani‐Sadrabadi Mohammad Mahdi , Dorri Nassir Mokarram , Ghaffarian Seyed Reza , Dashtimoghadam Erfan , Sarikhani Kaveh , Majedi Fatemeh S. 
Published: March 2010

AbstractNanocomposite polyelectrolyte membranes based on phosphoric acid (H3PO4) doped polybenzimidazoles (PBIs) with various loading weights of organically modified montmorillonite (OMMT) were prepared and characterized for direct methanol fuel cell (DMFC) applications. X‐ray diffraction analysis revealed the exfoliated structure of OMMT nanolayers in the polymeric matrices. An H3PO4–PBI/OMMT membrane composed of 500 mol % doped acid and 3.0 wt % OMMT showed a membrane selectivity of approximately 109,761 in comparison with 40,500 for Nafion 117 and also a higher power density (186 mW/cm2) than Nafion 117 (108 mW/cm2) for a single‐cell DMFC at a 5M methanol feed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Comparison of the thermo‐mechanical properties of chemically synthesized PMMA and PTEGDMA polymer
Authors: Velázquez‐Castillo R. , Galván‐Ruiz M. , Rivera‐Muñoz E.M. 
Published: March 2010

AbstractThe acrylic monomeric couple, methyl methacrylate (MMA)‐triethylene glycol dimethacrylate (TEGDMA) was mixed and polymerized through bulk polymerization in open test tubes using three different routes. The simplest one was a monomer mixture of 70 wt % of MMA and 30 wt % of TEGDMA. The polymerization reaction was initiated by benzoil peroxide (BPO). The second route used a casting syrup composed of 20 wt % polymethyl methacrylate (PMMA) dissolved in 80 wt % MMA. This casting syrup was mixed with 30 wt % TEGDMA to initiate the polymerization with BPO. The final synthesis route was carried out using the aforementioned chemical composition with a polymerization initiated with a mixture of BPO and N,N dimethyl p‐toluidine (DMT) at a ratio of 10 : 1. The three synthesis routes produced different types of polymers which have remarkable differences in morphology, thermal behavior, and tensile properties. Several thermal transitions were found in each type of polymer by using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Gas chromatography and Fourier transform infrared were employed to determine the cause of each thermal transition revealed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
The viscoelastic behavior of rubber under a complex loading. II. The effect large strains and the incorporation of carbon black
Authors: Suphadon N. , Thomas A.G. , Busfield J.J.C. 
Published: March 2010

AbstractSuphadon et al. (J App Polym Sci 2009, 113, 693) showed using small oscillations of less than 1% strain superimposed on a larger prestrain that the loss modulus, referred to the test piece dimensions after the application of the prestrain, did not vary with prestrain for unfilled rubber materials for a wide range of prestrains up to 100%. Also for unfilled rubbers it was observed that up to 100% prestrain that the loss modulus behavior was isotropic. This paper extends this previous work to larger prestrains for styrene butadiene rubber (SBR) compounds and natural rubber (NR) compounds some of which incorporate carbon black fillers. Both the storage modulus and the loss modulus are again calculated relative to the dimensions of the test piece after the application of the prestrain. These results show that for materials with 25 phr of carbon black filler, the loss modulus was still independent of the prestrain for normal engineering strains but at filler contents of 50 phr the loss modulus increases with prestrain at extension ratios less than 2. Even so over the typical engineering strains of below 50%, the loss modulus was still independent of strain. This increase in loss modulus at large prestrains can in part be explained by considering the molecular orientation of the polymer in combination with a consideration of the molecular slippage that takes place at the polymer filler interface. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Reef shark declines in remote atolls highlight the need for multi‐faceted conservation action
Authors: Graham Nicholas A. J. , Spalding Mark D. , Sheppard Charles R. C. 
Published: March 2010

AbstractThe decline of large‐bodied predatory species in the oceans is a concern both from a sustainability perspective and because such species can have important ecological roles. Sharks are particularly vulnerable to fishing as their life histories are characterized by late age at maturity, large body size, and low fecundity.Substantial shark population declines have been documented for a number of coastal and pelagic systems, with high population abundance limited to a few remote locations. The relative abundance and composition of reef shark populations are assessed from 1975 to 2006 at a remote, largely uninhabited, group of atolls in the central Indian Ocean; the Chagos Archipelago.Number of sharks observed per scientific dive declined from a mean of 4.2 in the 1970s to 0.4 in 2006, representing a decline of over 90%. Silvertip sharks displayed an increase in abundance from 1996, whereas blacktip and whitetip reef sharks were rarely encountered in 2006.Poaching in the archipelago, is the most likely cause of these declines, highlighted by a number of illegal vessels containing large numbers of sharks arrested since 1996. The data highlight that shark populations, even in remote, otherwise pristine, marine areas, are vulnerable to distant fishing fleets, and a range of strategies will need to be used in concert for their conservation. Copyright © 2010 John Wiley & Sons, Ltd.
Heritability of vasculopathy, autoimmune disease, and fibrosis in systemic sclerosis: A population‐based study
Authors: Frech Tracy , Khanna Dinesh , Markewitz Boaz , Mineau Geraldine , Pimentel Richard , Sawitzke Allen 
Published: March 2010

AbstractObjectiveTo investigate the familiality of systemic sclerosis (SSc) in relation to Raynaud's phenomenon (RP) (a marker of vasculopathy), other autoimmune inflammatory disease, and fibrotic interstitial lung disease (ILD).MethodsA genealogic resource, the Utah Population Database (UPDB), was used to test heritability of RP, other autoimmune disease, and ILD. Diseases were defined by International Classification of Diseases, Ninth Revision codes and identified from statewide discharge data, the University of Utah Health Science Center Enterprise Data Warehouse, and death certificates and were linked to the UPDB for analysis. Familial standardized incidence ratio (FSIR), relative risks (RRs) to first‐, second‐, third‐, and fourth‐degree relatives for SSc, RP, other autoimmune disease, and ILD (with 95% confidence intervals [95% CIs]), and population attributable risk (PAR) were calculated.ResultsA software kinship analysis tool was used to analyze 1,037 unique SSc patients. Fifty SSc families had significant FSIRs, ranging from 2.07 to 17.60. The adjusted PAR was ∼8%. The RRs were significant for other autoimmune disease in the first‐degree relatives (2.49 [95% CI 1.99–3.41],P= 2.42 × 10−15) and second‐degree relatives (1.48 [95% CI 1.34–2.39],P= 0.002), for RP in first‐degree relatives (6.38 [95% CI 3.44–11.83],P= 4.04 × 10−9) and second‐degree relatives (2.39 [95% CI 1.21–4.74],P= 0.012), and for ILD in first‐degree relatives (1.53 [95% CI 1.04–2.26],P= 0.03), third‐degree relatives (1.47 [95% CI 1.18–1.82],P= 0.0004), and fourth‐degree relatives (1.2 [95% CI 1.06–1.35],P= 0.004).ConclusionThese data suggest that SSc pedigrees include more RP, autoimmune inflammatory disease, and ILD than would be expected by chance. In SSc pedigrees, genetic predisposition to vasculopathy is the most frequent risk among first‐degree relatives.