bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pseudothermoset blends of poly (methyl methacrylate) and polypyrrole morphological, thermal, and conductivity studies
Authors: Ashraf S. M. , Ahmad Sharif , Riaz Ufana 
Published: April 2004

AbstractBlends of poly (methyl methacrylate) (PMMA)/Polypyrrole (PPy) were synthesized by emulsion polymerization of methyl methacrylate (MMA) and in situ oxidative polymerization of pyrrole (Py) with varying concentrations of Py and ferric chloride. The influence of the varying concentrations of ferric chloride, Py, and MMA on the morphological, spectral, thermal, and conductance characteristics of the blends were investigated. Hydrogen bonding between PPy and PMMA was inferred from FTIR studies that indicate blend formation. DSC and TGA analysis of the blends were done. A curious thermal behavior was observed that the blends lost their elasticity and flexibility on heating and turned into rigid and brittle material. DSC thermogram did not show glass transition temperature, indicating molecular and chain reorganization on heating. We have therefore called these blends pseudothermoset. The physicomechanical characteristics of the films of the blends were found to deteriorate with the increased ratio of ferric chloride in the blend, causing a decrease in the conductivity. Maximum conductivity (percolation threshold) was found at 14 wt % loading of Py in the blend (1.6 × 10−3 S cm−1), which was further correlated with the morphology of the films. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 82–91, 2004
Diffusion‐controlled polymer dissolution and drug release
Authors: Vrentas J. S. , Vrentas C. M. 
Published: April 2004

AbstractA model is formulated for diffusion‐controlled polymer dissolution and simultaneous drug release for amorphous, uncrosslinked polymers. Calculated fractional drug release versus time curves are similar to experimental curves reported in the literature. Solutions of the transport equations provide a way of illustrating how polymer type and molecular weight can be used in an attempt to approach a constant drug release rate. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 92–99, 2004
Twin‐screw extrusion compounding of polypropylene/organoclay nanocomposites modified by maleated polypropylenes
Authors: Wang Yeh , Chen Feng‐B. , Wu Kai‐C. 
Published: April 2004

AbstractPolypropylene/organoclay nanocomposites modified with different maleic anhydride grafted polypropylene (PPgMA) compatibilizers were compounded on a twin‐screw extruder. The effectiveness of the feeding sequence and compatibilizer type toward the dispersion of organoclay into PP matrix was critically studied. The composites prepared with side feed appeared to provide better dispersion and modulus improvement over that with hopper feed. The effect of PPgMA compatibilizers, including PB3150, PB3200, PB3000, and E43, with a wide range of maleic anhydride (MA) content and molecular weight was also examined. The structure was investigated with X‐ray diffraction and transmission electron microscopy. The relative complex viscosity curves also revealed a systematic trend with the extent of exfoliation and showed promise for quantifying the hybrid structure of the nanocomposites. Mechanical properties were determined by dynamical mechanical analysis and tensile and impact tests. Maleated polypropylene with low‐melt flow index and moderate MA content enhanced clay dispersion and resulted in significant improvement in tensile modulus of the nanocomposites. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 100–112, 2004
Shear flow behavior and oil distribution between phases in thermoplastic vulcanizates
Authors: Jayaraman Krishnamurthy , Kolli Venkata Giri , Kang Sang‐Yoon , Kumar Sharad , Ellul Maria D. 
Published: April 2004

AbstractThe high rate shear flow behavior and the morphology of five different oil‐extended polypropylene (PP)/ethylene‐propylene‐diene monomer (EPDM) thermoplastic vulcanizate blends were investigated with the melt flow rate (MFR) of the PP varying from 0.7 to 20. The ratio of rubber to PP is 70 : 30 in three of the thermoplastic vulcanizates (TPVs) and 50 : 50 in the other two TPVs. The distribution of the high‐temperature oil between the PP melt and the rubber is a key parameter because this will affect the viscosity of the PP/oil medium. The object of this study was to estimate the matrix composition in each of the TPVs at processing temperatures and to compare the shear viscosity of the effective matrix with that of the TPV. To this end, several PP/oil mixtures were prepared and their viscosity curves were correlated with the neat PP melt viscosity curves by means of shift factors varying with oil concentration. The oil distribution between the PP and rubber phases was estimated from TEM micrographs of the TPV blends. The results show that the PPs are mixed with oil to different proportions in the different TPVs and the viscosity curves of these mixtures exhibit the same trends in magnitude as the corresponding TPV viscosity curves. Hence, the shear flow of TPVs can be understood more readily in terms of the effective PP/oil medium flow behavior than in terms of the neat PP melt flow. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 113–121, 2004
Studies on surface tension of poly(vinyl alcohol): Effect of concentration, temperature, and addition of chaotropic agents
Authors: Bhattacharya A. , Ray P. 
Published: April 2004

AbstractIt is generally considered that the H‐bonds are responsible for the stabilization of network of PVA in water. The major types of intermolecular interactions from inorganic salts are responsible for the network of poly(vinyl alcohol) (PVA) and water, which ruptures the multiple H‐bonds between the OH groups of the polymer chains; therefore, various ions possessing abilities to affect these bonds result in salting out. It has been suggested that water molecules in the region of ionic hydration spheres must have strong orientation preferences, which could considerably restrict their ability to reorient and form hydration shells around nearby nonpolar solutes and thus affect the microstructure. In this article, our primary objective was to study the variation of surface tension, as it reflects the change in short‐range forces. Apart from this, we have also studied the surface tension behavior with the variation of concentration and temperature for different molecular weights of PVA. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 122–130, 2004
Optical‐limiting properties of poly(arylene ethynylenes) containing thiophene ring
Authors: Zhou Guijiang , Liu Yunqi , Ye Cheng 
Published: April 2004

AbstractPoly(arylene ethynylenes) containing thiophene ring were synthesized in good yield. In synthesis, pyridine was added to accelerate reaction owing to its phase transfer effect on CuI. The optical‐limiting properties of the prepared polymers were investigated with a Q‐switched Nd : YAG laser at 532 nm with 10‐ns pulse width. The experiments showed that the order of the optical‐limiting response of the polymers is poly(3‐hexyl‐2,5‐thienyleneethylene) (P3) > poly(2,5‐dihexyloxy‐1,4‐benzyleneethylene‐3‐hexyl‐2,5‐thienyleneethylene) (P2) > poly(9‐hexyl‐3,6‐carbazoleethylene‐3‐hexyl‐2,5‐thienyleneethylene) (P1). It can be understood well by the comparison of their conjugation length and D‐A structure. In addition, the results indicated that introducing the electron‐rich aromatic ring into the polymer backbone to enhance the D‐A structure would be an effective way to improve its optical‐limiting property. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 131–135, 2004
Waterborne anionomeric polyurethane–ureas from functionalized fluoropolyethers
Authors: Turri S. , Levi M. , Trombetta T. 
Published: April 2004

AbstractA family of anionomeric segmented polyurethane–ureas made from α‐ω dimethylol‐terminated perfluoropolyethers (Mn = 1000–2000), isophorone diisocyanate, dimethylol propionic acid, and ethylenediamine was obtained in form of stable aqueous dispersions. The dispersions were characterized by viscometry and dynamic laser light scattering. The main compositive parameters explored were the amount of COOH groups and the length of the fluorinated macromer. The new polyurethane–ureas were characterized by dynamic mechanical analysis obtaining information on modulus, thermal transition, and phase segregation. Surface properties and chemical resistance were estimated through measurements of static contact angles and spot tests with different solvents. Although surface hydrophobicity was not affected by composition, water‐sorption behavior was sensitive to the ionic character (COOH level) of the polymer. Diffusion and permeability coefficients of polymer films, having different carboxyl contents, were estimated. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 136–144, 2004
Cotton fabric graft copolymerization using microwave plasma. I. Universal attenuated total reflectance–FTIR study
Authors: Abidi Noureddine , Hequet Eric 
Published: April 2004

AbstractThe effect of microwave plasma on lightweight cotton fabric was investigated. N2‐plasma, O2‐plasma, and Ar‐plasma were obtained using a microwave generator at 2.45 GHz under vacuum. The universal attenuated total reflectance–Fourier transform infrared (UATR–FTIR) instrument was used to monitor the changes created after N2‐, O2‐, and Ar‐plasma treatments. The exposure of cotton fabrics to the plasma for 240 s with a microwave power of 500 W was sufficient to create active carbonyl groups, as shown by the presence of a peak around 1725 cm−1 in the FTIR spectra of the treated cotton fabrics. Ar‐plasma was found to generate more active groups than N2‐ and O2‐plasmas. The active centers created within the cellulose chains were used to initiate copolymerization reactions with vinyl monomers to impart hydrophobic character to lightweight cotton fabric. The efficiency of the grafting process and the presence of grafted monomers on fabric surface were confirmed using UATR–FTIR. Testing of treated fabric revealed that excellent water repellency was obtained. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 145–154, 2004
Rheological analysis of vapor‐grown carbon nanofiber‐reinforced polyethylene composites
Authors: Lozano Karen , Yang Shuying , Zeng Qiang 
Published: April 2004

AbstractThe melt rheological analysis of high‐density polyethylene reinforced with vapor‐grown carbon nanofibers (VGCNFs) was performed on an oscillatory rheometer. The influence of frequency, temperature, and nanofiber concentration (up to 30 wt %) on the rheological properties of composites was investigated. Specifically, the viscosity increase is accompanied by an increase in the elastic melt properties, represented by the storage modulus G′, which is much higher than the increase in the loss modulus G″. The composites and pure PE exhibit a typical shear thinning behavior as complex viscosity decreases rapidly with the increase of shearing frequency. The shear thinning behavior is much more pronounced for the composites with high fiber concentration. The rheological threshold value for this system was found to be around 10 wt % of VGCNF. The damping factor was reduced significantly by the inclusion of nanofibers into the matrix. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 155–162, 2004
Investigation on the cell nucleation and cell growth in microcellular foaming by means of temperature quenching
Authors: Sun Xinghua , Liu Huiju , Li Gang , Liao Xia , He Jiasong 
Published: April 2004

AbstractThe cell nucleation and real‐time cell growth with increasing cell growth time in microcellular foaming were investigated by means of temperature quenching in a supercritical CO2 pressure‐quench process. Samples of uniform size and shape were saturated in a vessel under conditions of 100–180°C and 30 MPa, and then depressurized to the atmosphere in 10 s. After depressurization, these samples were removed from the vessel at prescribed intervals, and immediately immersed in an ice‐water slurry to obtain foamed samples with various cell growth times. It was found that the nucleation density is closely correlated to the gas absorption capacity of the polymer matrix, so that the final cell density should not be adopted as the nucleation density, as done commonly. The change of cell structure and mass density with increasing cell growth time was dominated by gas diffusion behavior, which was strongly influenced by the temperature. The final cell structure was mainly determined by the cell growth step, where gas diffusion played a key role. The final cell density was in direct proportion to the gas remaining in the substrate, which ranged from 6.0 × 109 to 4.7 × 106 cells/cm3. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 163–171, 2004
Functionalization of polypropylene film by radiation grafting of acryloyl chloride and subsequent esterification with Disperse Red 1
Authors: Bucio Emilio , Burillo Guillermina , Del Pilar Carreón‐Castro María , Ogawa Takeshi 
Published: April 2004

AbstractPolypropylene (PP) films were grafted with acryloyl chloride by γ‐irradiation, and the grafted films were reacted with an azo dye, Disperse Red 1. The films were characterized by X‐ray diffraction, scanning electron microscopy, atomic force microscopy, and differential scanning calorimetry. It was found that the grafting takes place first on the film surface, and with increase in the radiation dose the grafting penetrated inside of the film, decreasing the crystallinity of the PP film. The surface of the films was homogeneous, and a mesophase was observed for the film grafted with the dye through a polarized optical microscope. The dye underwent trans to cis photoreaction, whereby the red films became colorless by the irradiation of UV light at room temperature, although the color was recovered on standing, and more quickly when heated. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 172–178, 2004
Effects of dispersed phase composition on thermoplastic polyolefins
Authors: Ha M. H. , Kim B. K. , Kim E. Y. 
Published: April 2004

AbstractTernary blends of polypropylene (PP), ethylene–octene copolymer (mPE), and high‐density polyethylene (HDPE) were prepared based on the phase behavior and physical properties of mPE/HDPE binary blends, and the results were interpreted in terms of morphology and both rheological and mechanical properties of the ternary blends as well as the binary blends. It was found that when mPE encapsulates HDPE in the PP matrix, compared to the encapsulation of mPE by HDPE, better blend properties were obtained, presumably because of the compatibilizing effect of mPE between PP and HDPE. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 179–188, 2004
Electrochemical polymerization of toluene in the mixed electrolytes of boron trifluoride diethyl etherate and trifluoroacetic acid
Authors: Li Enhua , Shi Gaoquan , Hong Xiaoyin , Wu Peiyi 
Published: April 2004

AbstractPoly(methylphenylene) (PMeP) films were prepared by direct oxidation of toluene in the mixed electrolytes of boron trifluoride diethyl etherate (BFEE) and trifluoroacetic acid (TFA). The oxidation potential of toluene in pure BFEE was measured to be 1.52 V versus saturated calomel electrode (SCE). This value was much lower than that determined in a neutral medium such as acetonitrile (2.13 V versus SCE). The introduction of TFA into BFEE decreased the oxidation potential of toluene and also improved the properties of as‐formed polymer films. Infrared and Raman spectra confirmed the formation of PMeP films. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 189–195, 2004
Preparation of cationic wheat starch by twin‐screw reactive extrusion
Authors: Tara Ahmed , Berzin Françoise , Tighzert Lan , Vergnes Bruno 
Published: April 2004

AbstractCationic starches were prepared in a corotating twin‐screw extruder by using wheat starch and two different reagents: 2.3‐epoxypropyltrimethylammonium chloride (Quab 151®) and 3‐chloro 2‐hydroxypropyltrimethylammonium (Quab 188®) in aqueous sodium hydroxide (NaOH). The different factors affecting this reaction were investigated. These factors include the extrusion conditions (feed rate, screw speed, barrel temperature), the reagent chemical structure, the starch plasticizer, and the molar ratio between Quab and NaOH. Degree of substitution (DS) and reaction efficiency (RE) were characterized, as well as starch transformation. High reaction efficiency (90%) can be reached for a low degree of substitution. It appears that the epoxy form of the reagent (Quab 151®) is more efficient in all processing conditions. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 201–208, 2004
Preparation and characterization of PVDF/silica hybrid membranes containing sulfonic acid groups
Authors: Kim Dae Sik , Park Ho Bum , Lee Young Moo , Park Young Hoon , Rhim Ji‐Won 
Published: April 2004

AbstractOrganic–inorganic hybrid membranes of poly(vinylidene fluoride)‐cohexafluoropropylene (PVDF‐HFP) and silica composites containing sulfonic acid groups were prepared via in situ polymerization of tetraethoxysilane (TEOS) and sulfosuccinic acid (SSA) using the sol‐gel process. The membranes containing more sulfonic acid groups showed a higher vapor sorption and greater swelling behavior. The bound and free water content of the membrane is proportional to the SSA concentration. However, the hybrid membranes without SSA do not have free water. The ion conductivity of the membranes is proportional to the SSA concentration. Silica content in the hybrid membrane without SSA had great effect on their mechanical properties. Tensile modulus and yield stress increased and yield strain and elongation at break decreased with increased silica content. However, in the case of the hybrid membrane containing SSA modulus, yield stress decreased and yield strain and elongation at break increased with increased silica content due to the weak interactions between the hydrophobic polymer chain and the hydrophilic group of SSA. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 209–218, 2004
Evaluation of physical properties and curing characteristics of silica‐filled ethylene–propylene–diene terpolymer in the presence of chloroprene rubber
Authors: Das Amit , Debnath Subhas Chandra , De Debapriya , Basu Dipak Kumar 
Published: April 2004

AbstractThe effect of addition of chloroprene rubber (CR) on the dispersion of silica in EPDM (ethylene–propylene–diene terpolymer) was studied. It was observed that physical properties of the vulcanizates could be significantly increased at the EPDM : CR blend ratio of 92.5 : 7.5. SEM micrographs also indicated that incorporation of CR into EPDM improves the network structure of the resulting vulcanizates. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 196–200, 2004
Synthesis of PMMA‐PTHF‐PMMA and PMMA‐PTHF‐PST linear and star block copolymers
Authors: Macit Hulya , Hazer Baki 
Published: April 2004

AbstractCombination of cationic, redox free radical, and thermal free radical polymerizations was performed to obtain linear and star polytetramethylene oxide (poly‐THF)‐polymethyl methacrylate (PMMA)/polystyrene (PSt) multiblock copolymers. Cationic polymerization of THF was initiated by the mixture of AgSbF6 and bis(4,4′ bromo‐methyl benzoyl) peroxide (BBP) or bis (3,5,3′,5′ dibromomethyl benzoyl) peroxide (BDBP) at 20°C to obtain linear and star poly‐THF initiators with Mw varying from 7,500 to 59,000 Da. Poly‐THF samples with hydroxyl ends were used in the methyl methacrylate (MMA) polymerization in the presence of Ce(IV) salt at 40°C to obtain poly(THF‐b‐MMA) block copolymers containing the peroxide group in the middle. Poly(MMA‐b‐THF) linear and star block copolymers having the peroxide group in the chain were used in the polymerization of methyl methacrylate (MMA) and styrene (St) at 80°C to obtain PMMA‐b‐PTHF‐b‐PMMA and PMMA‐b‐PTHF‐b‐PSt linear and star multiblock copolymers. Polymers obtained were characterizated by GPC, FT‐IR, DSC, TGA, 1H‐NMR, and 13C‐NMR techniques and the fractional precipitation method. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 219–226, 2004
The impact of oyster dredging on the growth of blue cod, Parapercis colias , in Foveaux Strait, New Zealand
Authors: Carbines Glen , Jiang Weimin , Beentjes Michael P. 
Published: April 2004

Abstract
Little is known about the potential impact of habitat modification by bottom fishing gear on the growth of demersal fishes. An analysis is presented for the growth of blue cod in Foveaux Strait, southern New Zealand, based on otoliths of fish captured from two sites in Foveaux Strait in 1999.
Each site contained two distinct areas of contrasting benthic habitat complexity, one area of relatively ‘complex’ recovering biogenic reef and another area of relatively ‘simple’ sand and gravel, both previously modified by oyster dredging.
Data were fitted to von Bertalanffy growth models for each sex of blue cod from the four areas sampled. No significant difference in growth models was observed for either male or female blue cod compared between the two types of habitat complexity at the eastern site. However, growth differed significantly for both sexes of blue cod from the two habitat types at the western site. Pairwise t‐tests further showed that growth differences only appeared biologically significant for the youngest blue cod sampled (3 years). These fish were, on average, 20% larger in complex biogenic reefs than in simple areas dredged by the oyster fishery.
These results suggest that on‐going disturbance and simplification of seabed habitat by the oyster fishery may impede the growth of juvenile blue cod. Areas of recovering biogenic reef may, therefore, provide important habitat for the recruitment and early development of blue cod in Foveaux Strait. Remedial actions may be required to protect some areas of recovering biogenic reef from further damage, and to allow dredged areas sufficient time to recover if the blue cod fishery and related resources are to be managed effectively.
Copyright © 2004 John Wiley & Sons, Ltd.
Identification of rat faecal, urinary and biliary metabolites of thionorphine, a novel mixed agonist‐antagonist analgesic, using liquid chromatography/electrospray ionization tandem mass spectrometry
Authors: Wei Shu‐xiang , Zhang Zhen‐qing , Wang Xiao‐ying , Guo Ji‐fen 
Published: April 2004

AbstractThe biotransformation of thionorphine (N‐cyclopropylmethyl‐7α‐[(s)‐1‐hydroxy‐1‐methyl‐3‐(2thiophene)‐propyl]‐6,14‐endo‐ethano tetrahydrooripavine), a new analgesic, was in‐vestigated in rats. The results of metabolite analysis by liquid chromatography/electrospray ionization tandem mass spectrometry with positive ion mode, in which a mobile phase of 10mM ammonium acetate (pH 3.0)/acetonitrile (25/75) was used, suggested that thionorphine is biotransformed to two potentially active metabolites, the N‐dealkylated thionorphine (M‐I) and the oxidized thionorphine (M‐II), and subsequently form conjugates with glucuronic acid of both thionorphine and the metabolites. Copyright © 2004 John Wiley & Sons, Ltd.
Adsorption of mercaptoacetic acid on a colloidal silver surface as investigated by Raman spectroscopy
Authors: Castro J. L. , López‐Ramírez M. R. , Centeno S. P. , Otero J. C. 
Published: April 2004

AbstractThe vibration ν(SH) has never been observed in the surface‐enhanced Raman scattering of mercaptoacetic acid recorded in a wide range of pH. This behavior enables us to deduce that the SH group is deprotonated and links to the metal forming an AgS bond as 1‐alkanethiols do. On the contrary, the carboxylic or carboxylate groups do not link to the metal and the carboxylic group is preserved even at pH values under which it should be deprotonated. This fact enables the stabilization of the adsorbed monolayer by removing the electrostatic repulsions between COO‐ groups and by the formation instead of hydrogen bonds between carboxylic groups. Only under rather basic conditions (pH > 8) does the carboxylic groups dissociate, but the νs(OCO) band is neither enhanced nor shifted toward low frequencies. © 2004 Wiley Periodicals, Inc. Biopolymers, 2004