bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and in vitro degradation of novel copolymers of cyclic carbonate and D,L‐lactide
Authors: Xu Jian , Liu Zhi‐Lan , Zhuo Ren‐Xi 
Published: May 2006

AbstractCyclic carbonate 9‐phenyl‐2,4,8,10‐tetraoxaspiro‐[5,5]undcane‐3‐one is a six‐membered carbonate monomer with a rigid side group. Novel biodegradable poly(carbonate‐ester), poly(9‐phenyl‐2,4,8,10‐tetraoxaspiro‐[5,5]undecan‐3‐one‐co‐D,L‐lactide) P(CC‐co‐DLLA), was synthesized by ring‐opening polymerization in bulk, using stannous octanoate catalyst. Effects of polymerization conditions such as catalyst concentration, reaction time, and reaction temperature on the polymerization were investigated. The structure of the copolymers was characterized by FTIR, 1H NMR, and 13C NMR. Their molecular weights and polydispersity index were determined by gel permeation chromatography. The protecting benzyl ketal group was removed subsequently by catalytic hydrogenation to give a poly(carbonate‐ester) containing pendant hydroxyl groups. The in vitro degradation of the copolymers was performed at (37 ± 0.5)°C in two media: phosphate buffer solution (pH 7.4) or Tris‐HCl buffer solution (pH 8.6) in the presence of proteinase K. The degradation rate can be regulated by adjusting the composition of two monomers. The pendant hydroxyl groups in the copolymers resulted in a prominent enhancement of the degradation rate in PBS. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1988–1994, 2006
Salt and pH responsive property of a starch‐based amphoteric superabsorbent hydrogel with quaternary ammonium and carboxyl groups (II)
Authors: Xu Shimei , Cao Liqin , Wu Ronglan , Wang Jide 
Published: May 2006

AbstractSwelling behaviors of a starch‐based amphoteric superabsorbent hydrogel cationic starch/sodium acrylate (CAS/AA) with quaternary ammonium and carboxyl groups were studied by immersion of the gels in various salt and pH solutions. It was found that swelling behaviors are heavily dependent of feed composition. Besides, it is also sensitive to pH, the concentration, and the ionic charge of the saline solution, but not to temperature. A kinetic study disclosed that the water transport mechanism in the CAS/AA was controlled by polymer relaxation. CAS/AA gels showed a good reversibility in the 0.9% NaCl solution after repeating the absorb‐dry process for more than 20 times. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1995–1999, 2006
Depolymerization of poly(ethylene terephthalate) wastes using ethanol and ethanol/water in supercritical conditions
Authors: De Castro Rubens E. N. , Vidotti Gentil J. , Rubira Adley F. , Muniz Edvani C. 
Published: May 2006

AbstractChemical recycling of poly(ethylene terephthalate) (PET) in supercritical ethanol has been investigated. In the presence of water, under supercritical conditions (temperature and pressure above 516 K and 6,384 kPa, respectively) excess ethanol reacts with PET to form diethyl terephthalate (DET) as the main product. A laboratory‐made 0.1L‐batch reactor was used at 528 K under pressures from 7,600 and 11,600 kPa. After the required reaction times, the reaction products were analyzed by reverse phase high pressure liquid chromatography and nuclear magnetic resonance. It was found that PET is completely depolymerized into monomers in about 5 h. The influences of water, pressure, ethanol/PET weight ratio, PET sources, as well as depolymerization time were investigated. Maximum DET recovery yield was 98.5%. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2009–2016, 2006
Preparation and anisotropic mechanical behavior of highly‐oriented electrospun poly(butylene terephthalate) fibers
Authors: Mathew G. , Hong J. P. , Rhee J. M. , Leo D. J. , Nah C. 
Published: May 2006

AbstractThis work describes the effect of the speed of drum‐type rotating collector in an electrospinning process on the orientation of electrospun poly(butylene terephthalate) fiber mats, and its effect on the tensile properties. The degree of orientation increased with the increase in the drum speed (surface velocity) up to a critical level, and thereafter, wavy fibers were observed. The average diameter reduced and its distribution became narrower with increase in the velocity. The mechanical properties in a parallel direction improved about three times with increase in the surface velocity. The anisotropic mechanical behavior could be predicted with a simple classical equation. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2017–2021, 2006
Property of ethylene vinyl acetate copolymer in melting processing
Authors: Chen Zhe , Fang Pengfei , Wang Hongmei , Zhang Shaoping , Wang Shaojie 
Published: May 2006

AbstractThe study is focused on the processing behavior of poly(ethylene‐co vinyl acetate) (EVA) in high temperature, such as 200°C. The specimens are characterized using HAAKE minilab, dynamic mechanical analysis (DMA), and positron annihilation lifetime spectroscopy (PALS) to understand the rheological behavior and microstructure of EVA. It was concluded that in high processing temperature, the viscosity declined first and then increased. The PALS results showed that the free volume of EVA became large at the beginning, and became small afterwards. The glass transition temperature measured with DMA got lower at first and then nearly unchanged with increasing handling time. The results can be explained that the degradation of EVA prevailed, and then degradation was not dominant. A good correlation has been found between the processing time and temperature of the transition point in the viscosity curve. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2022–2026, 2006
Viscoplastic deformation of an epoxy resin at elevated temperatures
Authors: Kontou E. 
Published: May 2006

AbstractThe tensile behavior under monotonic loading and stress‐relaxation testing of an epoxy resin has been studied. Experimental data at various strain rates and three temperatures from ambient up to just below Tg were performed, to study the transition from the brittle behavior to a ductile and therefore viscoplastic one. Dynamic mechanical analysis was applied to study the glass transition region of the material. Furthermore, a three‐dimensional viscoplastic model was used to simulate the experimental results. This model incorporates all features of yield, strain softening, strain hardening, and rate/temperature dependence. The multiplicative decomposition of the deformation tensor into an elastic and viscoplastic part has also been applied, following the element arrangement in the mechanical model. A stress‐dependent viscosity was controlling the stress–strain material behavior, involving model parameters, calculated from the Eyring plots. A new equation for the evolution of the activation volume with deformation was proposed, based on a probability density function. The model capability was further verified by applying the same set of parameters to predict with a good accuracy the stress‐relaxation data as well. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2027–2033, 2006
Shrink‐induced striped pattern on a thin gold film and switching of its orientation
Authors: Watanabe Masashi 
Published: May 2006

AbstractA well‐ordered striped pattern was formed on a thin gold film, which had been deposited using an ion sputtering technique onto an elastic silicone substrate prestretched by 20%. We also prepared a two‐layer (silicone/conducting rubber) substrate onto which a thin gold film with a striped pattern was produced using a similar method. By applying a voltage (24 V) between both ends of the conducting rubber to heat the substrate, I succeeded in reversibly changing the orientation of the striped pattern. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2040–2044, 2006
Water absorption behavior of acrylonitrile‐butadiene (NBR) latex impregnated jute nonwoven fabric composites
Authors: Kumar M. N. Satheesh , Siddaramaiah  
Published: May 2006

AbstractComposites were fabricated by impregnating the jute nonwoven fabric in acrylonitrile–butadiene (NBR) latex. The effect of different pickup ratio (dry, wt/wt) of NBR latex to jute nonwoven fabric, viz., 0.5 : 1, 1 : 1.5, 1.5 : 1, 2 : 1, and 2.5 : 1 on the water absorption behavior of the composites were evaluated. Water absorption studies were carried out at different temperatures, viz. 30, 50, and 70°C, based on immersion weight gain method. From the sorption result, the diffusion (D) and permeation (P) coefficients of water penetrant have been calculated. Significant increase in the diffusion and permeation coefficients was observed with increase in the temperature of sorption experiments. Drastic reductions in diffusion and permeation coefficients were noticed with increase in the pickup ratio of NBR on to jute nonwoven fabric. Attempts were made to estimate the empirical parameters like n, which suggests the mode of transport, and K is a constant that depends on the structural characteristics of the composite in addition to its interaction with water. The temperature dependence of the transport coefficients has been used to estimate the activation energy parameter for diffusion (ED) and permeation processes (Ep) from Arrhenius plots. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2045–2050, 2006
Properties of organic–inorganic composite materials prepared from acrylic resin emulsions and colloidal silicas
Authors: Wada Tamaki , Inui Kuniaki , Uragami Tadashi 
Published: May 2006

AbstractTo design an organic–inorganic composite material with colloidal silica as the inorganic component, an acrylic resin emulsion and an organic silane hybridized acrylic resin emulsion were prepared by emulsion polymerization. The organic–inorganic composite films were prepared by blending the emulsion and the colloidal silica. The contact angles for water, gloss at 60°, and the transparencies of those films were measured. The dispersion state of colloidal silica in films was observed with a scanning electron microscope (SEM) and a transmission electron microscope (TEM). From these results, the contact angle for water of the organic–inorganic composite film obtained from the silane hybridized acrylic resin emulsion was lower than that of the organic–inorganic composite film obtained from an acrylic resin emulsion. The contact angles for water in organic–inorganic composite films with colloidal silicas were lower than those of the films without the colloidal silicas. The films prepared from silane hybridized acrylic resin emulsion composites with colloidal silicas of less than 100 nm were more hydrophilic. SEM and TEM observations demonstrated that some aggregations of the small colloidal particle silica were densely dispersed on the film surface. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2051–2056, 2006
Poly(ethylene‐alt‐maleic acid) as complexing reagent to separate metal ions using membrane filtration
Authors: Rivas Bernabé L. , Pooley S. Amalia , Pereira Eduardo , Montoya Erika , Cid Rocío 
Published: May 2006

AbstractCommercial, water‐soluble poly(ethylene‐alt‐maleic anhydride), P(E‐alt‐MAn), was quantitatively hydrolyzed by 0.2M NaOH to yield poly(ethylene‐alt‐maleic acid), P(E‐alt‐MAc). The polymer structure is confirmed by FT‐IR spectroscopy. As the pH increases, metal ion affinity increases because the majority of the functional groups are present as carboxylate anions, which can form more stable complexes at a higher pH. By increasing the filtration factor, Z, metal ion affinity does not significantly decrease, which means that the ligand–metal interaction is strong and cannot be destroyed by washing with water at the filtration cell's pH. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2057–2061, 2006
Kinetic study of radical polymerization. IV. Determination of reactivity ratio in copolymerization of styrene and itaconic acid by 1H‐NMR
Authors: Mahdavian Ali Reza , Abdollahi Mahdi , Mokhtabad Leila , Reza Bijanzadeh Hamid , Ziaee Farshid 
Published: May 2006

AbstractHere, online 1H‐NMR spectroscopy has been successfully applied to investigate the kinetic parameters of radical copolymerization of styrene (St) and itaconic acid (IA). This technique was used because it allowed us to individually map out the monomer conversions of St and IA during the course of the polymerization at various conversions. This was possible because the individual contributions to the overall monomer conversion from St and IA could be measured through their nonoverlapping vinylic proton signals. The results of monomer conversion during the time in the corresponding 1H‐NMR spectra was the basis of our analysis to determine the reactivity ratios of St and IA in the solution and radical copolymerization reaction by several methods. In addition to linear least‐squares methods, such as Finemann–Ross, inverted Finemann–Ross, Mayo–Lewis, Kelen–Tudos, extended Kelen–Tudos, and Mao–Huglin, a nonlinear least‐square method (Tidwell–Mortimer) was used for this purpose, at low conversions. Extended Kelen–Tudos and Mao–Huglin were applied to determine the reactivity ratio values at high conversions too. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2062–2069, 2006
Preparation and characterization of genistein containing poly(ethylene glycol) microparticles
Authors: Motlekar Nusrat , Khan Mansoor A. , Youan Bi‐Botti C. 
Published: May 2006

AbstractThe purpose of this study was to prepare, characterize, and evaluate genistein‐containing microparticles with enhanced dissolution profile using poly(ethylene glycol) (PEG) as polymer matrix. Genistein loaded microparticles were prepared by a solvent evaporation process and their surface, thermal, chemical, and dissolution properties were analyzed by microscopy, differential scanning calorimetry, ATR‐FTIR spectroscopy, and USP dissolution apparatus II, respectively. The wettability index was also determined. Genistein exhibited an elongated crystal habit. However, the drug containing PEG microparticles were discrete and quasispherical. The ATR‐FTIR studies performed on the formulation suggested hydrogen bonding between the drug and the polymer matrix. Thermal analysis indicated a conversion of the crystalline form of the drug to an amorphous form. Genistein, exhibiting low solubility and high permeability, is a Class II drug of the Biopharmaceutical Classification Scheme. However, there was a ∼9‐fold increase in the rate of dissolution of genistein in the case of all formulations as compared to native genistein. This study showed that genistein could be effectively encapsulated into PEG microparticles using an emulsion‐solvent evaporation technique, therefore avoiding the potential disadvantages of other solid dispersion techniques. This approach provided a significant enhancement in the drug dissolution profile. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2070–2078, 2006
Structure and properties of UHMWPE fiber/carbon fiber hybrid composites
Authors: Lu Sheng‐Hua , Liang Guo‐Zheng , Zhou Zhi‐Wei , Li Fang 
Published: May 2006

AbstractUltrahigh molecular weight polyethylene (UHMWPE) fiber/carbon fiber hybrid composites were prepared by inner‐laminar and interlaminar hybrid way. The mechanical properties, dynamic mechanical analysis (DMA), and morphologies of the composites were investigated and compared with each other. The results show that the hybrid way was the major factor to affect mechanical and thermal properties of hybrid composites. The resultant properties of inner‐laminar hybrid composite were better than that of interlaminar hybrid composite. The bending strength, compressive strength, and interlaminar shear strength of hybrid composites increased with an increase in carbon fiber content. The impact strength of inner‐laminar hybrid composite was the largest (423.3 kJ/m2) for the UHMWPE fiber content at 43 wt % to carbon fiber. The results show that the storage modulus (E′), dissipation factor (tan δ), and loss modulus (E″) of the inner‐laminar hybrid composite shift toward high temperature remarkably. The results also indicate that the high‐performance composite with high strength and heat resistance may be prepared by fibers' hybrid. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1880–1884, 2006
Synthesis and characterization of xanthan gum‐g‐N‐vinyl formamide with a potassium monopersulfate/Ag(I) system
Authors: Banerjee Jaya , Srivastava Arti , Srivastava Abhishek , Behari Kunj 
Published: May 2006

AbstractA xanthan gum‐g‐N‐vinyl formamide graft copolymer was synthesized through the graft copolymerization of N‐vinyl formamide (NVF) onto xanthan gum with an efficient system, that is, potassium monopersulfate (PMS)/Ag(I) in an aqueous medium. The effects of the concentrations of Ag(I), PMS (KHSO5), hydrogen ion, xanthan gum, and NVF along with the time and temperature on the graft copolymerization were studied by the determination of the grafting parameters (grafting ratio, add‐on, conversion, grafting efficiency, and homopolymer) and the rate of grafting. The maximum grafting ratio was obtained at a 0.6 g/dm3 concentration of xanthan gum. All the parameters showed an increasing trend with an increasing concentration of peroxymonosulfate, except the homopolymer percentage, which showed a decreasing trend. The grafting ratio, add‐on conversion, grafting efficiency, and rate of grafting increased with the concentration of Ag(I) increasing from 0.8 × 10−2 to 1.2 × 10−2 mol/dm3. The optimum time and temperature for the maximum degree of grafting were 90 min and 35°C, respectively. The graft copolymer was characterized with IR spectral analysis, thermogravimetric analysis, and differential calorimetry analysis. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1637–1645, 2006
Energy of chemical bonds and spatial energy principles of the hybridization of atom orbitals
Authors: Korablev G. A. , Zaikov G. E. 
Published: May 2006

AbstractMethods for the evaluation of energy directedness of atom orbital hybridization and the calculation of the energy of chemical bonds in simple and complex structures are proposed on the basis of the application of the spatial energy parameter concept. Appropriate calculations and comparisons for 68 compounds were made. The calculation results agreed with the experimental data. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2101–2107, 2006
Time course and development of light adaptation processes in the outer zebrafish retina
Authors: Hodel Corinne , Neuhauss Stephan C.F. , Biehlmaier Oliver 
Published: May 2006

AbstractRetinomotor movements are morphological changes in the outer retina in response to changing light conditions. They can be separated into two components: Migration of pigment granules within the microvilli of the retinal pigment epithelium (RPE) and positional changes in photoreceptor cells. These positional changes optimize exposure of the cone and rod photoreceptors to light. The aim of this study was to analyze both the time course of retinomotor movements in the adult zebrafish and the maturation of these processes in the developing fish. We show that retinomotor movements are used as a dark/light adaptation mechanism in zebrafish. In adult zebrafish, melanin granules of the RPE migrate with constant speed and reach the fully light adapted (LA) state approximately after 1h. In contrast, about two thirds of double cone outer segment movements are finished in 5min, and are fully completed in 10 to 20min. During development there are three crucial stages leading to mature retinomotor movements in response to light: at 5dpf (days post fertilization) the migration of pigment granules begins, at 20dpf the pigment granules condense in the apical part of the RPE microvilli, and at 28dpf, concomitant with the functional maturation of rods, the double cones contract as in adult retinas. Anat Rec Part A 288A:653–662, 2006. © 2006 Wiley‐Liss, Inc.
On Egghe's version of continuous concentration theory
Authors: Burrell Quentin L. 
Published: May 2006

AbstractIn a recent article, Egghe (2005) discussed what he terms Lorenz concentration theory, covering the Lorenz curve and concentration measures such as the coefficient of variation and the Theil and Gini coefficients. In this note, we point out that neither the curve construction nor the concentration measures conform to the standard statistical/econometric definitions. We here give the standard formulations and apply them to the (truncated) Pareto distributions that are the subject of Egghe's (2005) article. We also interpret Egghe's usage.
On the solution of multislab atmospheric radiation problems with an arbitrary number and type of stationary layers
Authors: de Abreu Marcos Pimenta 
Published: May 2006

AbstractWe report here a computer implementation of a recently developed discrete ordinates methodology for efficiently solving a set of multislab atmospheric radiation problems with an arbitrary number and type of stationary layers. Numerical results are presented for a set of typical problems for a multislab model atmosphere in the shortwave. Copyright © 2006 Royal Meteorological Society
Effect of pierced metallic objects on sar distributions at 900 MHz
Authors: Fayos‐Fernandez Jose , Arranz‐Faz Carlos , Martinez‐Gonzalez Antonio M. , Sanchez‐Hernandez David 
Published: May 2006

AbstractA study of the interaction between mobile phone antennas and a human head in the presence of different types of metallic objects, attached and pierced to the compressed ear, is presented in this article. Computed and measured results have been performed by considering a quasi‐half‐wavelength dipole as the radiating source and measurements with the DASY4 dosimetric assessment system. Two different human head models have been implemented: a homogeneously shaped sphere and a three‐level head model with four different kinds of tissue. Antenna input impedance, reflection coefficient, radiation patterns, SAR distribution, absorbed power, and peak SAR values have been computed and measured for diverse scenarios, electromagnetic simulators, and organs. Despite the measuring accuracy limitations of the study, both simulated and measured results suggest that special attention has to be paid to peak SAR averaged values when wearing metallic objects close to the radiation source, since some increment of peak SAR averaged values is expected. Bioelectromagnetics 27:337–353, 2006. © 2006 Wiley‐Liss, Inc.
Computational verification of anesthesia effect on temperature variations in rabbit eyes exposed to 2.45 GHz microwave energy
Authors: Hirata Akimasa , Watanabe Soichi , Kojima Masami , Hata Ikuho , Wake Kanako , Taki Masao , Sasaki Kazuyuki , Fujiwara Osamu , Shiozawa Toshiyuki 
Published: May 2006

AbstractThis paper computationally verifies the effect of anesthesia on temperature variations in the rabbit eye due to microwave energy. The main reason for this investigation is that our previous paper suggested a reduction in blood flow due to the administration of anesthesia, resulting in an overestimated temperature increase. However, no quantitative investigation has yet been conducted. The finite‐difference time‐domain (FDTD) method is used for calculating power absorption and temperature variation in rabbits. For this purpose, we used a computational rabbit phantom, which is comprised of 12 tissues (including 6 eye tissues) with a resolution of 1 mm. Thermal constants of the rabbit were derived by comparing measured and calculated temperatures. For intense microwave exposure to the rabbit eye, time courses of calculated and measured temperatures were in good agreement for cases both with and without the administration of anesthesia. The point to be stressed is that under anesthesia the thermoregulatory response was inactivated and blood flow and basal metabolism was reduced. Bioelectromagnetics 27:602–612, 2006. © 2006 Wiley‐Liss, Inc.