bluuebunny/crossref_metadata_2025_split huggingface dataset:
Syntheses and adsorption properties for Hg2+ of chelating resin of crosslinked polystyrene‐supported 2,5‐dimercapto‐1,3,4‐thiodiazole
Authors: Qu Rongjun , Wang Chunhua , Sun Changmei , Ji Chunnuan , Cheng Guoxiang , Wang Xiaoqin , Xu Gang 
Published: March 2004

AbstractA novel chelating resin with functional group containing S and N atoms was prepared using chloromethylated polystyrene and 2,5‐dimercapto‐1,3,4‐thiodiazole (also called bismuththiol I, BMT) as materials. Its structure was characterized by infrared spectra and elementary analysis. The results showed that the content of the functional group was 2.07 mmol BMT g−1 resin, 47% of which were in the form of monosubstitution (PS‐BMT‐1) and 53% in the form of double substitution (PS‐BMT‐2). The adsorption for mercury ion was investigated. The adsorption dynamics showed that the adsorption was controlled by liquid film diffusion. Increasing the temperature was beneficial to adsorption. The Langmuir model was much better than the Freundlich model to describe the isothermal process. The adsorption activation energy (Ea), ΔG, ΔH, and ΔS values calculated were 18.56 kJ·mol−1, ‐5.99 kJ·mol−1, 16.38 kJ·mol−1, and 37.36, J·mol−1·K−1, respectively. The chelating resin could be easily regenerated by 2% thiourea in 0.1 mol·L−1 HCl with higher effectiveness. Five adsorption–desorption cycles demonstrated that this resin was suitable for repeated use without considerable change in adsorption capacity. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1646–1652, 2004
Thermal mechanical and dynamic mechanical property of biphenyl polyimide fibers
Authors: Zhang Qing‐Hua , Luo Wei‐Qiang , Gao Lian‐Xun , Chen Da‐Jun , Ding Meng‐Xian 
Published: March 2004

AbstractHigh‐performance polyimide fibers possess many excellent properties, e.g., outstanding thermal stability and mechanical properties and excellent radiation resistant and electrical properties. However, the preparation of fibers with good mechanical properties is very difficult. In this report, a biphenyl polyimide from 3,3′,4,4′‐biphenyltetracarboxylic dianhydride and 4,4′‐oxydianiline is synthesized in p‐chlorophenol by one‐step polymerization. The solution is spun into a coagulation bath of water and alcohol via dry‐jet wet‐spinning technology. Then, the fibers are drawn in two heating tubes. Thermal gravimetric analysis, thermal mechanical analysis, and dynamic mechanical analysis (DMA) are performed to study the properties of the fibers. The results show that the fibers have a good thermal stability at a temperature of more than 400°C. The linear coefficient of thermal expansion is negative in the solid state and the glass transition temperature is about 265°C. DMA spectra indicate that the tanδ of the fibers has three transition peaks, namely, α, β, and γ transition. The α and γ transition temperature, corresponding to the end‐group motion and glass transition, respectively, extensively depends on the applied frequency, while the β transition does not. The activation energy of α and γ transition is calculated using the Arrhenius equation and is 38.7 and 853 kJ/mol, respectively. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1653–1657, 2004
Use of pyrolysed oil shale as filler in poly(ethylene‐co‐vinyl alcohol)
Authors: Vasconcelos Barbosa Ronilson , Baumhardt‐Neto Ricardo , Santos Mauler Raquel , José Carlos , Gorga Perez , Gazzana Schneider Cláudia 
Published: March 2004

AbstractThe pyrolysed oil shale (POS) obtained from the pyrolysis of bituminous rock was used as filler in poly(ethylene‐co‐vinyl alcohol) (EVAL). The effects of vinyl alcohol content in the EVAL and the particle size of pyrolysed oil shale in the mechanical properties were investigated. The EVAL was prepared by hydrolysis of poly(ethylene‐co‐vinyl acetate) (EVA) with 8 and 18 wt % of vinyl alcohol content. The composites were prepared in a rotor mixer at 180°C with concentration of pyrolysed oil shale up to 5 wt %. Stress–strain plots of compression‐molded composites showed a synergic behavior in the mechanical properties for low concentrations (1–5 wt %) of POS in all particle sizes and EVAL used. Such behavior indicates a close packing and strong interactions between the inorganic filler and the polymer. Increasing of the vinyl alcohol content of EVAL improved the compatibility between the polymer and filler, but decreasing the POS particle size had no effect on the properties. The modulus and the ultimate tensile strength also increased in all concentrations of POS for both EVAL. Mechanical properties and dynamic mechanical analysis also demonstrated the compatibility between EVAL and POS. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1658–1665, 2004
Preparation and properties of unsaturated polyester–montmorillonite intercalated hybrid
Authors: Zhang Yonghua , Cai Qingyi , Jiang Zhijie , Gong Kecheng 
Published: March 2004

AbstractAn unsaturated polyester–organophilic montmorillonite hybrid was prepared by dispersing polymerizable quaternary ammonium‐modified montmorillonite in an unsaturated polyester resin, followed by cross‐linking reaction. The purpose of this investigation was to discover the role of the polymerizable group of quaternary ammonium in improving interfacial interaction between the silicate layers and polymer chains and the mechanical properties of unsaturated polyester–montmorillonite hybrids. It is found that when the content of organophilic montmorillonite is between 2 and 5%, the tensile strength, impact strength, heat resistance, and swelling resistance of the hybrid are obviously enhanced and are better than that of the composites prepared with pristine or nonpolymerizable quaternary ammonium‐modified montmorillonite. Results of X‐ray diffraction and transmission electron microscopy show that unsaturated polyester and styrene in the resin can be intercalated into the interlayer space of organophilic montmorillonites. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2038–2044, 2004
Modification of polystyrene by reactive extrusion with peroxide and trimethylolpropane triacrylate
Authors: Kyu Kim Byung , Ho Shon Kyung , Mo Jeong Han 
Published: March 2004

AbstractPolystyrene (PS) was modified by reactive extrusion with trimethylolpropane triacrylate (TMPTA) and dicumyl peroxide (DCP). The coupling reaction caused by TMPTA increased the molecular weight of PS, and this coupling reaction was enhanced in the presence of DCP at high TMPTA/DCP ratio. The rheological properties of the extrudate were examined. The impact strength of PS improved as the molecular weight increased by the coupling reaction. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1672–1679, 2004
Crystallization and melting behavior of 1,2‐syndiotactic polybutadiene
Authors: Bertini Fabio , Canetti Maurizio , Ricci Giovanni 
Published: March 2004

Abstract1,2‐Syndiotactic polybutadiene was synthesized at −30°C using the catalyst system CrCl2(dmpe)2‐MAO. The syndiotactic index of the butadiene sequences, expressed as a percentage of syndiotactic pentads [rrrr], was evaluated by 13C‐NMR measurements. WAXD and SAXS techniques were employed to characterize the crystalline structure of the polymer. The thermal behavior of the polybutadiene was investigated by differential scanning calorimetry. The isothermal crystallization kinetics were described by means of the Avrami equation, which suggested a three‐dimensional growth of crystalline units, developed by heterogeneous nucleation, followed by a secondary crystallization stage. Polybutadiene isothermally crystallizes from the melt according to regime II of crystallization described by Lauritzen–Hoffman secondary nucleation theory. Nonisothermal crystallization kinetics were elaborated using the Ziabicki and Avrami methods modified by Jeziorny. The equilibrium melting temperature was calculated. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1680–1687, 2004
Surface modification of ethylene‐co‐acrylic acid copolymer films: Addition of amide groups by covalently bonded amino acid intermediates
Authors: Luo Ning , Stewart Michael J. , Hirt Douglas E. , Husson Scott M. , Schwark Dwight W. 
Published: March 2004

AbstractAmide groups were anchored covalently on the surface of ethylene‐co‐acrylic acid (EAA) copolymer film by surface grafting of amino acid intermediates. The process consisted of four steps: conversion of carboxylic acid groups on the EAA surface to acid chloride groups, amino acid attachment, conversion of amino acid carboxyl groups to acid chloride groups, and amidation. All steps were carried out at room temperature. ATR‐FTIR spectroscopy was used to characterize the film after each step and to measure the kinetics of amino acid attachment. Three amino acids were studied: 12‐aminododecanoic acid (12‐ADDA), 5‐aminophthalic acid (5‐APA), and L‐aspartic acid (AA). The longer‐chain 12‐ADDA compound was selected for its chemical similarity to migratory fatty amides that are commonly used to alter the frictional behavior of polyolefin films. The 5‐APA and AA compounds were selected because each has two carboxylic acid groups that can be converted to amide groups. After amidation, the modified EAA films were characterized by static water contact angle measurements and scanning probe microscopy. Results showed that the 12‐ADDA reacted to the surface much faster than the 5‐APA or AA. Several steps of aggressive rinsing confirmed that the 12‐aminododecanamide was chemically anchored onto the EAA surface. As a result, both hydrophilicity and surface roughness were increased. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1688–1694, 2004
Preparation of silane‐terminated polystyrene and polymethylmethacrylate self‐assembled films on silicon wafer
Authors: Zhou Feng , Liu Weimin , Xu Tao , Liu Shujuan , Chen Miao , Liu Jianxi 
Published: March 2004

AbstractEnd silane functionalized polystyrene and polymethylmethacrylate were prepared through radical chain‐transfer reaction and characterized with gel‐permeation chromatography. The chain‐transfer constants of mercaptopropyltrimethoxysilane for the polymerization of styrene and methylmethacrylate were determined to be 8.48 and 0.67, respectively, from the slopes of 1/DPn versus [S]/[M] lines. The ultrathin films of the end silane–terminated polymers were prepared by self‐assembly onto hydroxylated silicon wafers. The water contact angle on the resulting ultrathin films and the film thickness were measured. The morphology and chemical features of the films were observed and investigated by means of atomic force microscopy and X‐ray photoelectron spectroscopy. Results indicated that the chain‐transfer agent played a key role in making it possible for the silane‐terminated polystyrene and polymethylmethacrylate to be self‐assembled on Si(111), whereas the thickness and surface quality of the ultrathin films were dependent on the molecular weights of the polymers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1695–1701, 2004
Structure and properties of polyamide 6 blends with low‐density polyethylene grafted by itaconic acid and with neutralized carboxyl groups
Authors: Pesetskii S. S. , Krivoguz Y. M. , Jurkowski B. 
Published: March 2004

AbstractA comparative study of the structure and properties of two‐phase blends of polyamide 6 (PA6) and low‐density polyethylene (LDPE) modified in the course of reactive extrusion, by grafting of itaconic acid (IA) without neutralization of carboxyl groups (LDPE‐g‐IA) and with neutralized carboxyl groups (LDPE‐g‐IA−M+) was carried out. It was shown that 30 wt % of LDPE‐g‐IA−M+ introduced to PA6 resulted in blends of higher Charpy impact strength compared with that of PA6/LDPE‐g‐IA blends. The maximum increase was achieved when Mg(OH)2 was used as a neutralizing agent. The blend morphology has a two‐phase structure with blurred interphases because of increased adhesion between the phases. The neutralization of carboxyl groups in grafted IA did not lead to two‐phase morphology of blends, which had a negative influence on the mechanical properties. It is believed that the differences in the impact strength were caused by the influence of the added neutralizing agents on the structure of interphases, which depends on both the interfaces adhesion and structural effects resulting from the nucleating behavior of the neutralizing agent. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1702–1708, 2004
Preparation and characterization of sulfonated polyetherimide/polyetherimide blend membranes
Authors: Shen Li‐Qiang , Xu Zhi‐Kang , Yang Qian , Sun Hang‐Lin , Wang Shu‐Yuan , Xu You‐Yi 
Published: March 2004

AbstractPolyetherimide (PEI) was sulfonated by chlorosulfonic acid (CSA) in 1,2‐dichloroethane for the first time. With the increase of the CSA/PEI repeat unit ratio and/or reaction time, the ion‐exchange capacity (IEC) of the sulfonated polyetherimide (SPEI) increased accordingly. Water‐uptake testing and contact‐angle measurement showed that the hydrophilicity of the SPEI increases with the increase of the IEC. Membranes were fabricated from SPEI/PEI blends with different ratios. The morphologies of the blend membranes were examined by scanning electron microscopy, which showed that the membrane pore size is larger when SPEI with higher IEC was used. With the increase of SPEI ratio in the blend membranes, the membrane pore size also increased. The contact‐angle data of the membranes showed that the hydrophilicity of the blend membrane was elevated because of the sulfonate group on the SPEI molecular backbone. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1709–1715, 2004
Preparation and characterization of starch/polycaprolactone blend
Authors: Kweon Dong‐Keon , Kawasaki Norioki , Nakayama Atsuyoshi , Aiba Seiichi 
Published: March 2004

AbstractTo make starch/polycaprolactone (PCL) blend with high miscibility, starch was chlorinated (starch‐Cl) by using methanesulfonylchloride (CH3SO2Cl) in dimethylformamide (DMF) prior to blending. Starch‐Cl/PCL blends were prepared by the mixing between starch‐Cl and PCL solutions under various conditions. To study the change of structure, thermal and physical characteristics of starch‐Cl/PCL blend, FTIR, DSC, SEM, and solvent resistance were measured. By blending starch‐Cl and PCL, a chemical reaction occurred partially in blend (FTIR result); thereby, the miscibility (DSC and SEM results) and solvent resistance were increased. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1716–1723, 2004
Surface hydrolysis of filaments based on poly(trimethylene terephthalate) spun at high spinning speeds
Authors: Kotek Richard , Jung Dong‐Wook , Kim Joon Ho , Smith Brent , Guzman Patricia , Schmidt Benjamin 
Published: March 2004

AbstractThe surface alkaline hydrolysis of fibers made from poly(trimethylene terephthalate) (PTT) was studied after extruding the polymer at high spinning speeds from 2000 to 6000 m/min and heat setting in the range of temperatures from 100 to 180°C. Fiber weight loss increased with an increasing heat‐setting temperature but it was also dependent on the spinning speed. Some of the partially hydrolyzed fibers had a well‐developed, hydrophilic surface, and pore size in the range of 0.69 to 1.20 μm. The optimum reaction and morphological conditions for increasing porosity in PTT fibers depends on spinning speed and heat‐setting temperature. A temperature of 180°C is the upper limit for heat‐setting PTT filaments but seems to be the most effective for making porous fibers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1724–1730, 2004
Electrical/pH responsive properties of poly(2‐acrylamido‐2‐methylpropane sulfonic acid)/hyaluronic acid hydrogels
Authors: Kim Seon Jeong , Lee Chang Kee , Kim Sun I. 
Published: March 2004

AbstractPoly(2‐acrylamido‐2‐methylpropane sulfonic acid) (PAMPS)/hyaluronic acid (HA) interpenetrating polymer network (IPN) hydrogels have been prepared by using the sequential‐IPN method. The IPN hydrogels exhibited swelling behavior in solutions at various pHs, in NaCl solutions, and under electrical DC stimulation. The IPN hydrogels were highly swollen in water, but lost much of their water capacity when transferred to solutions having a high ionic strength. The IPN hydrogels showed a significant responsive deswelling in an applied electric field. This behavior indicates the potential application of IPN hydrogels as biomaterials. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1731–1736, 2004
Thermal and thermooxidative degradation of engineering thermoplastics and life estimation
Authors: Gupta Y. N. , Chakraborty Amitabh , Pandey G. D. , Setua D. K. 
Published: March 2004

AbstractThis investigation deals with the thermal or thermooxidative degradation behavior of three engineering polymers [e.g., poly(ethylene terephthalate) (PET), poly(ether sulfone) (PES), and poly(ether ether ketone) (PEEK)] by using thermogravimetry‐coupled mass spectrometry (TG‐MS) analysis. The experiments were conducted both in argon and in air separately to study the changes in the degradation pattern of the polymers under varied sample environments. The samples were subjected to a programmed heating rate of 10°C/min and a temperature range from ambient to 800°C. For all these polymers, the decomposition rate, percentage weight loss, and the nature of the evolved gases were found to vary while changing the environment from argon to air. Methods of nonisothermal kinetic analysis, proposed by Flynn and Wall, and the shelf life estimation, proposed by Toop, have been described. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1737–1748, 2004
In situ polymerization of titanium isopropoxide in polycaprolactone: Properties and characterization of the hybrid nanocomposites
Authors: Wu Chin‐San 
Published: March 2004

AbstractIn this study, tetra isopropyl ortho titanate (TTIP) and polycaprolactone (PCL) were chosen as the ceramic precursor and the continuous phase, respectively, for the preparation of novel nanocomposites by using an in situ sol‐gel process. In addition, acrylic acid grafted polycaprolactone (PCL‐g‐AA) was investigated as an alternative to PCL. The hybrids (PCL/TiO2 and PCL‐g‐AA/TiO2) were characterized via Fourier transform infrared (FTIR) spectroscopy, dynamic mechanical thermal analysis (DMA), X‐ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetry analysis (TGA), and Instron mechanical testing. It was found that the carboxylic acid groups of acrylic acid acted as coordination sites for the titania phase to form chemical bonds, thus improving the properties of the acrylic acid grafted composite compared with its acrylic‐acid‐free counterpart. The TiO2 content also determined the strength of interfacial bonding between the polymer chains and the ceramic phase, as shown by changes in glass transition temperature (Tg) with TiO2 content. The maximum values of tensile strength and Tg were obtained with the PCL‐g‐AA/TiO2 composite at 10 wt % TiO2. At TiO2 contents above this, excess particles led to segregation between the organic and inorganic phases. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1749–1757, 2004
A governing equation for physical aging of thick and thin fluoropolyimide films
Authors: Zhou Chun , Chung Tai‐Shung , Wang Rong , Hong Goh Suat 
Published: March 2004

AbstractAn equation based on the segmental/chain mobility in free volume theory was derived to correlate the gas permeation coefficient and the aging time. An accelerated physical aging of a fluoropolyimide was observed and employed to validate this equation. A strong thickness‐dependent aging process was found by employing pure O2 and N2 tests to monitor the change of gas permeation properties as a function of aging time. Experimental results also suggest that chain rigidity and configuration play important roles in physical aging. As a result, the thin 2,2′‐bis(3,4′‐dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) based polyimide films studied here have different permeability versus time relationship from conventional polyarylate in the early stage of aging, and the experimental data seem to fit the proposed equation well. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1758–1764, 2004
Study on the macrokinetics of poly(trimethylene terephthalate) polycondensation reaction
Authors: Chen Kequan , Tang Xiaozhen , Chen Shangwei , Fu Gang 
Published: March 2004

AbstractThe macrokinetics of poly(trimethylene terephthalate) (PTT) polycondensation reaction during the high‐vacuum process was studied. The results showed that PTT polycondensation reaction may be considered as a second‐order reaction and thermal degradation is negligible in mathematical handling. The intrinsic viscosity versus time undergoes two different processes according to temperature. The apparent reaction rate constants and apparent activation energy of PTT polycondensation reaction are smaller than those of PET. Under efficient stirring, PTT polycondensation reaction is still reaction‐controlled and the role of devolatilization could be neglected even during the high‐vacuum process. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1765–1770, 2004
Interfacial effects in polypropylene–silica nanocomposites
Authors: Rong Min Zhi , Zhang Ming Qiu , Pan Shun Long , Friedrich Klaus 
Published: March 2004

AbstractGrafted inorganic nanoparticles can greatly improve the mechanical performance of polymers. To examine the effects of the interfacial characteristics generated by the grafting polymer bonded to nanoparticle surfaces, we chemically grafted nano‐silica with different polymers and then melt‐mixed it with polypropylene (PP). We extracted the homopolymers produced during the graft polymerization from the grafted products before the composites were manufactured to get rid of the side effects of the nongrafting polymers. We tailored the interfacial interaction between the grafted nano‐SiO2and PP matrix by changing the amount of the grafting polymers on the nanoparticles, that is, the grafting percentage. Mechanical tests indicated that all the composites incorporated with grafted nano‐SiO2particles possessed much higher impact strength than untreated SiO2/PP composites and neat PP. The greatest contribution of the particles was made at a low grafting percentage. Tensile measurements showed that the treated nanoparticles could provide PP with stiffening, strengthening, and toughening effects at a rather low filler content (typically 0.8 vol %) because of the enhanced interfacial adhesion resulting from molecular entanglement and interdiffusion between the grating polymers on the nanoparticles and matrix macromolecules. The presence of grafting polymers on the nanoparticles provided the composites with a tailorable interphase. The tensile performance of the composites was sensitive to the nature of the grafting polymers. Basically, a hard interface was beneficial to stress transfer, whereas a soft one hindered the development of cavities in the matrix. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1771–1781, 2004
Morphological study of poly(vinylidene fluoride) asymmetric membranes: Effects of the solvent, additive, and dope temperature
Authors: Yeow M. L. , Liu Y. T. , Li K. 
Published: March 2004

AbstractAsymmetric poly(vinylidene fluoride) (PVDF) membranes were cast with commercial‐grade Kynar K760 polymer pellets and four different solvent systems: N,N‐dimethylacetamide (DMAc), N,N‐dimethylformamide, 1‐methyl‐2‐pyrrolidone, and triethyl phosphate. With a focus on the PVDF/DMAc system, the effects of various additives (i.e., ethanol, glycerol, lithium chloride, lithium perchlorate, and water) on the resulting membrane morphology were investigated. The membrane morphology was examined with scanning electron microscopy. The effect of the dope solution temperature on the membrane morphology was also studied for the various additives used. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1782–1789, 2004