bluuebunny/crossref_metadata_2025 huggingface dataset:
Properties of a new synthetic rubber: High‐trans 1,4‐poly(butadiene‐co‐isoprene) rubber
Authors: He Aihua , Yao Wei , Huang Baochen , Huang Yaqin , Jiao Shuke
Published: March 2004

A high‐trans 1,4‐butadiene/isoprene copolymer (TBIP) was synthesized in a 5‐L autoclave with hydrogen as an effective molecular weight modifier. The effects of hydrogen on the catalyst efficiency and molecular weight of the copolymers were investigated. The processability and physicomechanical properties of TBIP and their relationship to the composition, composition distribution, and molecular weight of TBIP were examined in detail. Increasing the H2pressure effectively reduced the molecular weight of TBIP. The optimum Mooney viscosity of TBIP and the 1,4‐butadiene molar content in the feed were 30–50 and 5–25%, respectively. No cis–trans isomerization was observed during the roll processing procedure for TBIP. The vulcanization characteristics of TBIP were similar to those of general rubbers, and no reverse vulcanization was observed for TBIP. A high green strength was the typical characteristic of TBIP. Vulcanized TBIP (TBIR) with an optimum composition and molecular weight presented outstanding antifatigue properties and low heat buildup in comparison with general rubbers. Compared with general sidewall stock [natural rubber (NR)/butadiene rubber (BR) = 50/50], TBIR exhibited a greater than 15‐fold increase in its crack‐initiation resistance. The other mechanical properties of TBIR were similar to those of 50/50 NR/BR. The heat‐aging mechanism of TBIR was crosslinking aging. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2941‐2948, 2004
Ethylenediamine tetraacetic acid modification of crosslinked chitosan designed for a novel metal‐ion adsorbent
Authors: Shimizu Yoshiaki , Izumi Sinya , Saito Yoshihiro , Yamaoka Hitoshi
Published: March 2004

Novel chitosan‐based adsorbent materials were synthesized with a higher fatty diacid diglycidyl as a crosslinking agent, and the adsorption ability of the resulting polymers for several metal ions was evaluated. Selective adsorption for Cu2+ in comparison with other divalent metal ions, such as Ni2+, Pb2+, Cd2+, and Ca2+, was observed with the crosslinked chitosan sorbent at pH 6; however, the adsorption power decreased abruptly as the pH value of the solution decreased. The addition of ethylenediamine tetraacetic acid (EDTA) residues to crosslinked chitosan significantly enhanced the adsorption power for metal ions, especially for Ca2+. The adsorptivity of Ca2+ was dramatically improved with the introduction of EDTA residues, and the value was greater than that obtained with a commercial chelate resin (CR11). Although the adsorption power of the EDTA‐derivatized sorbent for other metal ions was just comparable to that of the CR11 material, the newly synthesized adsorbent could be used for the recovery of metal ions from industrial waste solutions with a relatively wide range of pHs, from 4.0 to 6.0. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2758–2764, 2004
Structural characterization of polymer blends based on polysulfones
Authors: Linares A. , Acosta J. L.
Published: March 2004

A series of blends with various compositions was prepared on the basis of polysulfone, polyethersulfone, and polyimide. These blends were characterized by different techniques, including Fourier transform IR spectroscopy, differential scanning calorimetry, dynamic mechanical analysis, and tensile stress–strain measurements. The results obtained allowed for certain conclusions regarding blend compatibility. In addition, the mechanical properties were subjected to an experimental test design to measure the blends for tensile break strength and Young's modulus with a computer program, which eventually enabled us to obtain the surface response equations of both properties and also to predict the optimum composition presenting the best mechanical behavior. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3030–3039, 2004
Removal of metal ions by water‐soluble polymacromonomers in conjunction with ultrafiltration membrane
Authors: Rivas Bernabé L. , Pooley S. Amalia , Maureira Antonio
Published: March 2004

The macromonomer polyethylene glycol methylether methacrylate was homo‐ and copolymerized with 2‐acrylamido‐2‐methyl‐1‐propane sulfonic acid under three feed monomer ratios. The initiator used was ammonium peroxydisulfate (0.2 mol %). All the polymers were completely soluble in water. The copolymer composition was determined by elemental analysis. The metal ion interaction capability of the three polymers was investigated through the liquid‐phase polymer‐based retention (LPR) technique at different values of pH and filtration factor Z. The highest metal ion retention ability was observed at pH 5.0. The homopolymer showed a high selectivity for Ni(II) ions at pH 3.0. The copolymers (PEGMEM)1.51‐co‐(APSA)1.00 and (PEGMEM)1.00‐co‐(APSA)1.95 showed a high selectivity for Cr(III) ions at pH 3.0. The maximum retention capacity, in general, was similar for the homo‐ and copolymers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2955–2960, 2004
Allyl ether‐modified unsaturated polyesters for UV/air dual‐curable coatings. I: Synthesis and characterization of the oligomers and their cured films
Authors: Yuan Huiya , Lu Xueyi , Zeng Zhaohua , Yang Jianwen , Chen Yonglie
Published: March 2004

Allyl ether (AE)‐modified unsaturated polyester oligomers were synthesized from polyethylene glycol (PEG), maleic anhydride (MAH), and trimethylolpropane mono allyl ether (TMPAE), and characterized by Fourier transform infrared (FTIR) spectra. The UV/air dual‐curable coatings were prepared from the oligomers using vinyl ether (VE) as a reactive diluent. FTIR spectra showed that CC bonds in the coating composition had polymerized partially after cured by UV or air. The investigation of rheological behavior of the dual curable composition suggested that all the systems belonged to pseudoplastic fluid, and the increasing allyloxy content in oligomer resulted in a higher viscosity. Differential scanning calorimetry (DSC) analysis showed that the increasing TMPAE‐PEG molar ratio resulted in lower Tg, and all samples had the same glass transition temperature irrespective of the type of curing. The results of TGA for cured films indicated that UV‐cured film had better thermal stability than the air‐cured one. The air‐cured film showed superior pencil hardness, impact strength, and flexibility to the UV‐cured counterpart. However, the air‐cured film had poor adhesion and electric resistance properties. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2765–2770, 2004
Allyl ether‐modified unsaturated polyesters for UV/air dual‐curable coatings. II: UV and air‐curing behavior
Authors: Yuan Huiya , Lu Xueyi , Zeng Zhaohua , Yang Jianwen , Chen Yonglie
Published: March 2004

The photoinduced and peroxide‐induced polymerization behavior of dual‐curable allyl ether‐modified unsaturated polyester (AUPE) and vinyl ether (VE) used as a reactive diluent for dual‐curable coating have been studied by infrared spectroscopy (IR). For UV curing systems in N2 atmosphere, the maleate's conversion and total conversion decrease with the increasing of allyloxy content. However, the rate and of copolymerization and conversion of VE are independent of allyloxy concentration. The copolymerization of allyl ether (AE) and vinyl ether occurs in the presence of maleate (MA) under UV irradiation. For air curing, the rate of copolymerization increases with allyloxy content. The ultimate conversion is the same irrespective of the allyloxy concentration. Because the electron‐rich double bond of allyloxy would become an electron‐deficient one through oxidation, the conversion of maleate decreases with increasing of the allyloxy content due to the enhancement of copolymerization of AE with VE. The ATR‐IR showed that different curing mechanisms occur in AUPE/VE system during air‐curing process. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2771–2776, 2004
Synthesis and properties of photoluminescent copolymer containing 1,3,4‐oxadiazole and carbazole rings
Authors: Chen Zhaobin , Liu Yufang , Zhang Caihong , Bai Fenglian
Published: March 2004

The luminescent copolymer 2‐phenyl‐5‐[3′‐(methacrylamido)phenyl]‐1,3,4‐oxadiazole and vinylcarbazole (PMAPO–VCZ), combining hole‐facilitating moiety, carbazole ring, and electron‐facilitating moiety, 1,3,4‐oxadiazole, as side groups, was synthesized by a radical polymerization of the olefinic monomer PMAPO and VCZ. For comparison, the homopolymer P‐PMAPO was also synthesized by similar procedures. The solubility, thermal, and optical properties of the copolymers were investigated. The synthesized copolymer was soluble in common organic solvents but the homopolymer of PMAPO was dissolved only by hot THF. Thermogravimetric analysis and differential scanning calorimetry measurements showed that the copolymer and homopolymer exhibit good thermal stability up to 360 and 340°C with glass‐transition temperatures higher than 105 and 65°C, respectively. The photoluminescence properties were investigated. The results showed that the copolymer emits blue and blue‐green light and the emission spectra of monomer and polymers exhibit obvious solvent effect. With the increase of polarity of solvents, the fluorescence spectra distinctly change, appearing with a red shift at room temperature. The concentration‐dependent emission spectra change significantly with the increase of concentration. In addition, when N,N‐dimethylaniline (DMA) was gradually added to the solution of copolymers, the emission intensity of fluorescence was dramatically increased. However, when the concentration of DMA was increased beyond a certain level, the emission intensity of fluorescence gradually decreased. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2777–2783, 2004
Dynamic mechanical analysis of poly(trimethylene terephthalate)—A comparison with poly(ethylene terephthalate) and poly(ethylene naphthalate)
Authors: Mackintosh Allan R. , Liggat John J.
Published: March 2004

The fiber properties of PTT have been the subject of several reports, although very few reports describe the properties of molded specimens. In this work, the dynamic mechanical relaxation behavior of compression‐molded PTT films has been investigated. The added flexibility of the PTT was found to lower the temperature of the β‐ and α‐transitions relative to the PET and PEN. The results suggest that the β‐transition is at least two relaxations for PET and PTT due to the increase in the breadth of the relaxation. The results seem to support the hypothesized mechanism of others, in that the β‐transition involves the relaxation of the carbonyl entity and the aromatic C1–C4 ring flips for PTT and PET, and the relaxation of the carbonyl for PEN. The β*‐ and α‐transitions for all three polymers seem to be cooperative in nature. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2791–2796, 2004
Phase behavior of ternary polymer blends with hydrogen bonding
Authors: Hsu Wen‐Ping
Published: March 2004

Atactic poly (methyl methacrylate) (aPMMA) was found to be almost completely immiscible with poly(vinyl acetate) (PVAc). Both aPMMA and PVAc are known to be miscible with poly(vinyl phenol) (PVPh) according to literature. Adding of PVPh into immiscible aPMMA/PVAc mixtures is likely to improve their miscibility. Therefore, PVPh can be used as cosolvent to cosolubilize aPMMA and PVAc. A ternary blend consisting of aPMMA, PVAc, and PVPh was prepared and determined calorimetrically in this article. According to the calorimetry data, the ternary blend was determined to be miscible. The reason for the observed miscibility is because the interactions between PVAc and PVPh are similar to those between aPMMA and PVPh. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2797–2802, 2004
Antioxidant presence in thick‐walled high‐density polyethylene materials after rotational molding
Authors: Weick Brian L. , Al‐Zubi Raed S.
Published: March 2004

High‐density polyethylene (HDPE) sample tanks manufactured by using a rotational molding process were used in a study to determine the presence and characteristics of antioxidants at the inside and outside surfaces of the tanks. The sample tanks were manufactured by using three different processing times to create undercooked, ideal, and overcooked tanks. Differential scanning calorimetry (DSC) was used to perform oxidation induction time (OIT) studies by using specimens cut from the surfaces of the tank. The OIT portion of the analysis exposes the melted HDPE specimens to an oxygen environment at 200°C for over 2 h. The DSC monitors change in the energy transfer rate to or from the specimen because of chemical reactions. A numerical integration process was used to analyze the DSC‐OIT data and to obtain additional information about the energy levels measured during the analysis. Fourier transform infrared (FTIR) studies were also performed to determine the chemical characteristics of specimens cut from the processed tanks. Results showed increased degradation at the inside surfaces of the overcooked tanks because of a lack of antioxidants. The results also showed that metal ions from the mold wall could react with the outside surfaces of the tanks and influence the level of antioxidants at that surface. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3052–3066, 2004
Preparation and characterization of titanium dioxide core/polymer shell hybrid composite particles prepared by emulsion polymerization
Authors: Yu Dong‐Guk , An Jeong Ho , Bae Jin Young , Lee Yong Eui , Ahn Seong Deok , Kang Seung‐Youl , Suh Kyung Soo
Published: March 2004

Titanium dioxide inorganic core and polymer shell composite poly(methyl methacrylate‐co‐butylacrylate‐co‐methacrylic acid) [P(MMA‐co‐BA)‐MAA] particles were prepared by emulsion copolymerization. Fourier transform IR (FTIR) spectroscopy was used to measure the content of MAA composite particles. Dynamic light scattering (DLS) characterized the composite particle size and size distribution. The field emission SEM (FE‐SEM) results of the composite particles showed regular spherical shape and no bare TiO2 was detected on the whole surface of the samples. The composite particles were produced, showing good spectral reflectance compared with bare TiO2. TGA results indicated the encapsulation efficiency and estimated density of composite particles. Encapsulation efficiency was up to 78.9% and the density ranged from 1.76 to 1.94 g/cm3. Estimated density of the composite particles is suitable to 1.73 g/cm3, due to density matching with suspending media. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2970–2975, 2004
A kinetic study on the autocatalytic cure reaction of a cyanate ester resin
Authors: Chen Ching‐Chung , Don Trong‐Ming , Lin Tai‐Hung , Cheng Liao‐Ping
Published: March 2004

The cure of a novolac‐type cyanate ester monomer, which reacts to form a polycyanurate network, was investigated by using differential scanning calorimeter. The conversions and the rates of cure were determined from the exothermic curves at several isothermal temperatures (513–553 K). The experimental data, showing an autocatalytic behavior, conforms to the kinetic model proposed by Kamal, which includes two reaction orders, m and n, and two rate constants, k1 and k2. These kinetic parameters for each curing temperature were obtained by using Kenny's graphic‐analytical technique. The overall reaction order was about 1.99 (m = 0.99, n = 1.0) and the activation energies for the rate constants, k1 and k2, were 80.9 and 82.3 kJ/mol, respectively. The results show that the autocatalytic model predicted the curing kinetics very well at high curing temperatures. However, at low curing temperatures, deviation from experimental data was observed after gelation occurred. The kinetic model was, therefore, modified to predict the cure kinetics over the whole range of conversion. After modification, the overall reaction order slightly decreased to be 1.94 (m = 0.95, n = 0.99), and the activation energies for the rate constants, k1 and k2, were found to be 86.4 and 80.2 kJ/mol. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3067–3079, 2004
Zone drawing and zone annealing of poly(ethylene terephthalate) microfiber prepared by CO2 laser thinning
Authors: Suzuki Akihiro , Okano Takahiro
Published: March 2004

A zone‐drawing and zone‐annealing method was applied to a poly(ethylene terephthalate) microfiber, obtained by using CO2 laser thinning, to develop its mechanical properties. The microfiber used for the zone drawing and zone annealing was prepared by winding at 1386 m/min the microfiber obtained by irradiating the laser at 18.1 W/cm2 and had a diameter of 2.8 μm and a birefringence of 0.097. Zone drawing was carried out at a drawing temperature of 105°C under an applied tension of 53 MPa, and zone annealing at an annealing temperature of 155°C under 195 MPa applied tension. Zone drawing and zone annealing were carried out at a treatment speed of 0.21 m/min. The diameter of the microfiber decreased, and its birefringence increased, with zone drawing and zone annealing. The zone‐annealed microfiber finally obtained had a diameter of 2 μm, a birefringence of 0.234, a tensile modulus of 17.9 GPa, and a tensile strength of 1.1 GPa. The wide‐angle X‐ray diffraction photograph of the zone‐annealed microfiber showed the existence of highly oriented crystallites. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2989–2994, 2004
Radiation synthesis and environmental responsiveness of semi‐interpenetrating polymer networks composed of poly(dimethyl–aminoethyl methacrylate) and poly(ethylene oxide)
Authors: Liu Zhugen , Yi Min , Zhai Maolin , Ha Hongfei , Luo Zhifu , Xiang Xueqing
Published: March 2004

Semi‐interpenetrating polymer networks (semi‐IPNs) composed of poly(dimethyl–aminoethyl methacrylate) (PDMAEMA) and poly(ethylene oxide) (PEO) were synthesized by γ‐radiation; three semi‐IPNs with 80 : 20, 90 : 10, and 95 : 5 weight ratios of DMAEMA/PEO were obtained by use of this technique. The gel–dose curves showed that the hydrogels were characterized by a structure typical of semi‐IPNs and the results of elemental analysis supported this point. The temperature‐induced phase transition of semi‐IPNs with the composition of 95 : 5 was still retained, with the lower critical solution temperature of PDMAEMA shifting from 40 to 27°C. The temperature sensitivity of the other two semi‐IPNs gradually disappeared. The pH sensitivity of three semi‐IPNs was still retained but the pH shifted slightly to lower values with increasing PEO content in the semi‐IPNs. The effect of PEO content in semi‐IPNs on their environmental responsiveness was discussed. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2995–3001, 2004
Water vapor permeability and mechanical properties of fabrics coated with shape‐memory polyurethane
Authors: Cho Jae Whan , Jung Yong Chae , Chun Byoung Chul , Chung Yong‐Chan
Published: March 2004

Water vapor permeable fabrics were prepared by coating shape‐memory polyurethane (PU), which was synthesized from poly(tetramethylene glycol), 4,4′‐methylene bis(phenylisocyanate), and 1,4‐butanediol, onto polyester woven fabrics. Water vapor permeability and mechanical properties were investigated as a function of PU hard‐segment content or polymer concentration of the coating solution. Water vapor permeability of PU‐coated fabrics decreased dramatically with increased concentration of coating solution, whereas only a slight change was observed with the control of PU hard‐segment content. The coated fabric showed the clear appearance of a nonporous PU surface according to SEM measurements. Attainment of high water permeability in PU‐coated fabrics is considered to arise from the smart permeability characteristics of PU. Mechanical properties of coated fabrics, although there was some variation depending on the concentration of coating solution, were primarily affected by PU hard‐segment content. Fabrics coated with PU hard‐segment content of 40% showed the lowest breaking stress and modulus as well as the highest breaking elongation, which could be interpreted in terms of the dependency of mechanical properties of coated fabrics on PU hard‐segment content and the yarn mobility arising from a difference in penetrating degree of coating solution into the fabric. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2812–2816, 2004
Modified emulsifier‐free emulsion polymerization of butyl methacrylate with ionic or/and nonionic comonomers
Authors: Xu Xiao‐Jun , Chen Fengxi
Published: March 2004

A modified emulsifier‐free emulsion polymerization of butyl methacrylate (BMA) with ionic or/and nonionic comonomers was successfully used to prepare nanosized poly(butyl methacrylate) (PBMA) latices with high polymer contents. After seeding particles were generated in an initial emulsion system, consisting of a portion of BMA, water, ionic comonomer [sodium styrenesulfonate (NaSS)] or nonionic comonomer [2‐hydroxyethyl methacrylate (HEMA)] and potassium persulfate, most of the BMA monomer or the mixture of BMA and HEMA was added dropwise to the polymerizing emulsion over a period of 6–12 h. Stable latices with high PBMA contents up to 27% were obtained. It was found that the latex particle sizes (2Rh) were largely reduced (34 nm) by the continuous addition of monomer(s) compared to those (107 nm) obtained by the batch polymerization method. The effect of comonomer concentration on the particle size, the number of PBMA particles/mL of latex (Nd), and the molar mass (Mw) of copolymer during the polymerization were discussed. The surface compositions of latex particles were analyzed by X‐ray photoelectron spectroscopy, indicating that the surface of latex particles was significantly enriched in NaSS or/and HEMA. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3080–3087, 2004
Studying the mechanisms of titanium dioxide as ultraviolet‐blocking additive for films and fabrics by an improved scheme
Authors: Yang Hongying , Zhu Sukang , Pan Ning
Published: March 2004

Titanium dioxide (TiO2) has good ultraviolet (UV)‐blocking power and is very attractive in practical applications because of such advantages as nontoxicity, chemical stability at high temperature, and permanent stability under UV exposure, for example. Development of nanoscience and ‐technology provides new ways for better treatment for UV‐resistant films and fabrics using TiO2. However, the exact mechanisms of TiO2 as a UV‐blocking additive are still not very clear, and researchers hold different views on this issue. The aim of this investigation was to study systematically the mechanisms of TiO2 as a UV‐blocking additive for films and fabrics. To achieve this goal, the conventional scheme describing light interactions with fabrics was revised based on more recent progress in optical theory, and special experiments and analytic methods were used in the investigation. Several effects attributed to the nanoscale additives were identified. Moreover, detailed analyses based on the results yielded a few important suggestions useful in developing or improving both inorganic UV‐blocking agents and the UV‐protective films and textiles. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3201–3210, 2004
Effects of solvent adsorption on solution properties of poly(vinyl alcohol)/dimethylsulfoxide/water ternary systems
Authors: Hong Shi‐Jie , Huang Hsing‐Tsai , Hong Po‐Da
Published: March 2004

In this study, the solvent adsorption phenomena of poly(vinyl alcohol) (PVA) in cosolvent mixtures of dimethylsulfoxide (DMSO; solvent 1) and water (solvent 2) were investigated. Typically, this cosolvent mixture could form hydrogen‐bonded DMSO/(water)2 complexes, involving one DMSO and two water molecules. Because of the complex formation in the cosolvent mixtures, PVA chains preferentially adsorb water molecules at DMSO mole fraction X1 < 0.33, but preferentially adsorb DMSO molecules at X1 > 0.33. The preferential adsorption of DMSO (a good solvent for PVA) could cause the relatively extended conformation of PVA chains in solutions because of the increase in excluded volume effect. Because of various interactions between PVA chains and cosolvent mixtures, the aggregation and gelation behaviors of PVA solutions were significantly affected by the composition of cosolvent mixture. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3211–3217, 2004
Crashworthiness of automotive composite material systems
Authors: Jacob George C. , Fellers John F. , Starbuck J. Michael , Simunovic Srdan
Published: March 2004

The energy absorption capability of a composite material is important in developing improved human safety in an automotive crash. In passenger vehicles, the ability to absorb impact energy and be survivable for the occupant is called the crashworthiness of the structure. The crashworthiness in terms of the specific energy absorption (SEA) of a chopped carbon fiber (CCF) composite material system was compared with that of other fiber resin systems such as graphite/epoxy cross‐ply laminates (CP#1 and CP#2), a graphite/epoxy‐braided material system (O), and a glass‐reinforced continuous‐strand mat (CSM). The quantity of these material systems needed to ensure passenger safety in a midsize car traveling at various velocities was calculated and compared. The SEA of the chopped carbon fiber composite material was the highest compared to that of all the other composites investigated. It was calculated that only 4.27 kg of it would need to be placed at specific places in the car to ensure passenger safety in the event of a crash at 15.5 m/s (35 mph). This clearly led to an important practical conclusion that only a reasonable amount of this composite material is required to meet the necessary impact performance standard. The CCF composite tested at 5 mm/min crushing speed met both the criteria that need to be satisfied before a material is deemed highly crashworthy: A high magnitude of energy absorption and a safe allowable rate of this energy absorption. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3218–3225, 2004
Determination of the saturation adsorption of surfactant in polymer latices
Authors: Roose P. , De Doncker P.
Published: March 2004

The volumetric determination of the surfactant adsorption density at maximum packing (saturation) is studied in binary latex blends. A phenomenological description for latex mixtures that are not free of surfactant prior to titration predicts a quadratic dependence for the saturation adsorption density as a function of the fractional surface area of the latex compounds. The expected behavior was verified experimentally from conductometric titrations of sodium dodecyl sulfate in blends of homopolymer latices cleaned with the serum replacement technique. Accordingly, it is shown that surfactant titration of binary latex blends provides indications about the level of cleaning of the mixed compounds. Furthermore, when latex mixtures are prepared by using a surfactant‐free reference latex, this approach may be used for the estimation of the saturation adsorption area of the bare polymer surface for an incompletely cleaned latex. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3226–3230, 2004
Biodegradable soy protein–polyester blends by reactive extrusion process
Authors: Graiver D. , Waikul L. H. , Berger C. , Narayan R.
Published: March 2004

Blends of soy protein concentrate and biodegradable polyester (Eastar Bio Copolyester, EPE) were prepared by using glycerol as a compatibilizing agent. Good miscibility was obtained only when the soy protein was initially combined with glycerol under high shear and at elevated temperatures in an extruder. Under these conditions, partial denaturing of the soy protein led to specific interactions between functional groups of the protein with the glycerol. The extrusion conditions and appropriate screw configuration were the critical factors affecting the reactivity of the protein and hence, the properties of the blends. Screws with large kneading blocks that produced high shear mixing were preferred and led to thermoplastic blends characterized by high elongation and high tensile strength. The morphology of these soy protein/polyester blends was studied by using environmental scanning electron microscopy (ESEM) and indicated good wetting of the soy protein particles within the polyester matrix. The thermal properties were studied by differential scanning calorimetry (DSC) and showed a lower degree of crystallinity and a continuous depression of the melting point of the polyester as the concentration of protein was increased. The possibility of using soy protein concentrate instead of the more expensive (higher purity) soy protein isolate in the preparation of biodegradable resins should lead to new commercial opportunities based on renewable, agricultural byproducts. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3231–3239, 2004
Memory effects in supramolecular networks of diacids and polyfunctional pyridine derivatives
Authors: Wiegel Kurt N. , Griffin Anselm C. , Black Micah S. , Schiraldi David A.
Published: March 2004

Highly crosslinked networks were produced through a series of diacids and tetrakis pyridyls. These materials displayed complex crystallization behaviors over multiple heat/cool cycles. The shifting of crystallization behaviors with time in the melt phase seems to indicate that the materials move toward thermodynamically ideal structures. This behavior is suggestive of a type of memory in which the networks remember the morphological structure previous to the melt and improve upon that structure in the next cooling cycle. The network/memory phenomena observed in small molecule diacid/tetrapyridyl systems also appeared to exist when poly(ethylene terephthalate) (PET) polymer was used as the source of carboxylic acid functionalities. The same time‐ dependent behaviors, suggestive of sequential steps toward thermodynamically optimum states, were observed when the PET/tetrapyridyl systems were thermally cycled. It was also observed that complexation of tetrapyridyl with PET brought about a significant change in oxygen gas barrier properties; these changes were opposite to those obtained when covalent crosslinks were introduced into PET. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3097–3106, 2004
Determination of monomer reactivity ratios using in situ FTIR spectroscopy for maleic anhydride/norbornene‐free‐radical copolymerization
Authors: Pasquale Anthony J. , Long Timothy E.
Published: March 2004

Monomer reactivity ratios for maleic anhydride (MAH) and norbornene (Nb) free‐radical copolymerizations were estimated by using a linear graphical method, which is based upon the terminal model developed by Mayo and Lewis. Reactions were performed by using optimized reaction conditions that were previously determined. MAH/Nb copolymerizations (3 mol % AIBN initiator, 60% solids in THF, 65°C, 24 h). Copolymerization data were collected via in situ FTIR to low degrees of conversion (∼ 10%) for copolymerizations of MAH and Nb. The following five different MAH/Nb comonomer feed molar ratios were analyzed: 40/60, 45/55, 50/50, 55/45, and 60/40. Conversion data that were measured with in situ FTIR were employed in the rearranged copolymer composition equation to estimate MAH and Nb reactivity ratios. Both of the reactivity ratios were determined to be near 0 (rMAH = 0.02, rNb = 0.01), which was indicative of an alternating copolymerization mechanism. The highest observed rate constant for copolymerization was obtained at an equal molar concentration of monomers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3240–3246, 2004
Effect of hydroperoxide decomposer and slipping agent on recycling of polypropylene
Authors: Agrawal Ashwini K. , Singh Sanjeev K. , Utreja Amit
Published: March 2004

Polypropylene (PP) recycling has always been challenging because the polymer is highly susceptible to thermooxidative degradation during extrusion. Recycled (degraded) PP is normally blended with virgin PP to achieve reasonable mechanical properties after reprocessing operations. However, impurities present in recycled PP tend to degrade even the virgin PP in this process. In this study, standard recycled PP was produced in a laboratory by repeated extrusion and pelletization operations of virgin PP. This material was blended with virgin PP in a ratio from 3 : 7 to 7 : 3. An attempt was made to stabilize the recycled blend by adding a peroxide decomposer (triphenylphosphite, TPP) and a slipping agent (zinc stearate) in contrast to radical scavengers normally used in reprocessing. It was found that by using 0.3–0.5 wt % of TPP and 2 wt % of zinc stearate, this degradation could be effectively attested. Compared to the tensile strength retention of 68% (based on strength of pure virgin PP) of a 60 : 40 (recycled : virgin) PP blend without any stabilizer, a value of 77% was obtained for the same blend with the above‐mentioned stabilizers. This stabilization effect was attributed to decomposition of unstable hydroperoxides to stable compounds in the recycled materials by TPP, and lower generation of new radicals in the presence of zinc stearate. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3247–3251, 2004
Internal lipid content and viscoelastic behavior of wool fibers
Authors: Marti M. , Manich A. M. , Ussman M. H. , Bondia I. , Parra J. L. , Coderch L.
Published: March 2004

Wool is a natural keratin fiber made up of cuticle and cortical cells held together by the cell membrane complex (CMC), which contains few internal lipids (IWLs) (1.5% by mass). IWL arouse considerable cosmetic and dermatological interest because of its high proportion of ceramides. In this work, IWLs were extracted with acetone, methanol, and dichloromethane/acetone solvents, and the possible alteration of the extracted fibers with respect to their textile feasibility was analyzed. Parameters of yield, fibril, and matrix viscoelastic behavior, deformation work, and breaking elongation were useful in highlighting the effect of internal wool lipids on the mechanical properties of the fibers. The extraction with acetone and methanol solvents supplied good yields of IWL. Although extraction with methanol achieved the richest extracts, the fibers were chemically modified. By contrast, although acetone‐extracted fibers had similar properties after treatment, alkaline solubility was lower and fiber length and barb were superior. In the mechanical analysis, a prior extraction of IWL increased yield tenacity and decreased the elongation at break of the fibers, maintaining the feasibility of extracted wool for textile purposes. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3252–3259, 2004
Antinociceptive Properties of Chloromaleinimides and their Sulphonyl Derivatives
Authors: Walter Maria Elena , Mora Cristiano , Mundstock Karoline , de Souza Mércia M. , de Oliveira Pinheiro Andréia , Yunes Rosendo Augusto , Nunes Ricardo J.
Published: March 2004

This report describes the synthesis of new cyclic imides obtained from the reaction between aniline and dichloromaleic anhydride with further chlorosulphonation as well as the reaction between different amines and 4‐methoxyphenol for the synthesis of imidobenzenesulphonyl derivatives. These compounds were tested as antinociceptive agents using the writhing test on mice. Some compounds, when intraperitoneally injected, proved to be potent and dose‐related antinociceptives, being several times more active than many known reference drugs.
Matrix Metallo‐Proteinase (MMP‐2) Organoboronate Inhibitors
Authors: Ali Hijazi Abu , Berkovitz Ronny , Reich Reuven , Srebnik Morris
Published: March 2004

Novel organoboronate derivatives consisting of BB, BC(R1R2)B, BCCB, CBC, Department of Medicinal RBC=CBB, and RBC=CBP structures were synthesized and have been investigated in vitro as MMP‐2 inhibitors. We discovered that most of the boronate derivatives (those not containing phosphorus) showed significant activity against MMP‐2. The trisboronate 14 proved to be a potent MMP‐2 inhibitor at 5 and 10 μM. Structure activity relationships (SARs) data for the compounds were investigated and are discussed.
Two New Arylnaphthalide Lignans and Antiplatelet Constituents from Justicia procumbens
Authors: Weng Jing‐Ru , Ko Horng‐Huey , Yeh Ting‐Li , Lin Hsien‐Cheng , Lin Chun‐Nan
Published: March 2004

Two new arylnaphthalide lignans, procumphthalide A (1) and 4‐O‐β‐D‐glucopyranosyl‐(1‴→2″)‐β‐D‐apiofuranosyldiphyllin, named procumbenoside B (2), along with cilinaphthalide B (3) and several other known compounds were isolated from the methanolic extracts of Justicia procumbens. By using NMR and other spectral methods, the structures of 1 and 2 were elucidated. Cilinaphthalide B (3), justicidin A (4), and taiwan E methyl ether (5) were shown to have an antiplatelet effect in human plateletrich plasma. In human citrated PRP, 5 showed a strong inhibitory effect on platelet aggregation induced by adrenaline in a concentration‐dependent manner, with an IC50 value of about 27.6 μM.
Open knowledge management: Lessons from the open source revolution
Authors: Awazu Yukika , Desouza Kevin C.
Published: March 2004

One might argue that the future of knowledge work is manifested in how open‐source communities work. Knowledge work, as argued by Drucker (1968); Davenport, Thomas, and Cantrell (2002); and others, is comprised of specialists who collaborate via exchange of know‐how and skills to develop products and services. This is exactly what an open‐source community does. To this end, in this brief communication we conduct an examination of open‐source communities and generate insights on how to augment current knowledge management practices in organizations. The goal is to entice scholars to transform closed knowledge management agendas that exist in organizations to ones that are representative of the open‐source revolution.
Assessment of satisfaction with care after inpatient treatment for oesophageal and gastric cancer
Authors: Kavadas V , Barham C P , Finch-Jones M D , Vickers J , Sanford E , Alderson D , Blazeby J M
Published: March 2004

Background

Patients' views are becoming increasingly important in the current health system. They provide information on effectiveness of healthcare and how it may be improved. This study aimed to measure patients' satisfaction with care received for treatment of oesophageal and gastric cancer, and to identify areas that contribute most to overall satisfaction scores.

Methods

Consecutive inpatients with oesophageal and gastric cancer treated in one surgical unit were recruited prospectively during a 2-year period. The European Organization for Research and Treatment of Cancer ‘satisfaction with in-hospital care’ questionnaire (QLQ-SAT32) was completed following discharge. Scores ranged from 0 to 100 for each satisfaction scale. Univariable and multivariable analysis was used to define the relationships between the different dimensions of satisfaction with care and the overall score.

Results

Ninety-one patients (mean age 67 years, 60 men) completed the questionnaire a mean of 40 days after treatment. The highest scores were for doctors (mean 72), nurses (mean 67) and overall satisfaction (mean 68). Univariable analysis showed that all dimensions of satisfaction with care contributed significantly to overall satisfaction (P < 0·001). Multivariable analyses, however, showed that most of the variation in overall satisfaction could be attributed to levels of satisfaction with doctors, nurses, and hospital comfort and cleanliness.

Conclusion

Satisfaction with care in these surgical patients was high and could be measured using a multidimensional instrument. Overall satisfaction was not influenced equally by all aspects of care. The strongest contributors to overall satisfaction in this study were doctors, nurses and hospital cleanliness.
Role of surgical portosystemic shunts in the era of interventional radiology and liver transplantation
Authors: Orug T , Soonawalla Z F , Tekin K , Olliff S P , Buckels J A C , Mayer A D
Published: March 2004

Background

In the present era of liver transplantation and transjugular intrahepatic portosystemic shunts, the role and choice of shunt surgery for portal hypertension was reviewed.

Methods

This retrospective study analysed the management of patients with portal hypertension in a tertiary liver transplant unit between June 1993 and May 2002. During this 9-year interval, 394 patients underwent endoscopic control of varices, 235 transjugular intrahepatic portosystemic shunts were inserted, 1142 liver transplants were performed, while only 29 patients needed a surgical portosystemic shunt.

Results

Twenty-nine shunt operations were performed in nine patients with cirrhosis, one patient with congenital hepatic fibrosis and 19 without parenchymal liver disease. There were 12 side-to-side lienorenal, nine mesocaval, three proximal lienorenal, two distal lienorenal, two portacaval and one mesoportal shunts. Encephalopathy was seen in five of 11 patients with a non-selective shunt, but did not occur after side-to-side or selective lienorenal shunt procedures. At a median follow-up of 42·5 months, one mesocaval shunt had thrombosed and one portacaval shunt had stenosed; both were successfully managed by percutaneous intervention. To date, six patients have died; two succumbed to postoperative complications, one of which was related to the shunt.

Conclusion

Patients with Budd–Chiari syndrome and cirrhosis can nearly always be managed by a combination of endoscopy, interventional radiology and liver transplantation. In the rare instances when these therapies fail in patients with cirrhosis, a side-to-side lienorenal shunt is a good option.
Effects of training and supervision on recurrence rate after inguinal hernia repair
Authors: Robson A J , Wallace C G , Sharma A K , Nixon S J , Paterson-Brown S
Published: March 2004

Background

There is little information about the effects of operative experience and supervision of trainees on outcome in inguinal hernia surgery, one of the cornerstone operations of basic surgical training.

Methods

All primary inguinal hernia repairs carried out between 1994 and 2001 were registered prospectively in the Lothian Surgical Audit database. Subsequent problems that required re-referral were identified from this database. Patients who required reoperation for recurrence a median of 3 (range 1–7) years after surgery were identified.

Results

Some 4406 repairs, including 90 recurrences (2·0 per cent), were identified. Open mesh, open sutured and laparoscopic techniques were employed. Senior trainees (registrars and senior registrars) had similar recurrence rates to consultants; supervision did not affect outcome. Junior trainees (senior house officers) had similar recurrence rates to consultants as long as they were supervised by either a senior trainee or a consultant. Unsupervised junior trainees had unacceptably high recurrence rates (open mesh: relative risk (RR) 21·0 (95 per cent confidence interval (c.i.) 7·3 to 59·9), P < 0·001; open sutured: RR 16·5 (95 per cent c.i. 7·2 to 37·8), P < 0·001).

Conclusion

Senior trainees may operate independently and supervise junior trainees, with recurrence rates equal to those of consultant surgeons. Junior trainees should be encouraged and given more practice in inguinal hernia repair with appropriate supervision.
Sacral nerve stimulation for faecal incontinence in the UK
Authors: Jarrett M E D , Varma J S , Duthie G S , Nicholls R J , Kamm M A
Published: March 2004

Background

Sacral nerve stimulation (SNS) is an effective therapy for faecal incontinence. Published studies derive largely from single centres and there is a need to determine the broader applicability of this procedure.

Methods

Prospective data were collected for all patients undergoing SNS in the UK. Records were reviewed to determine the outcome of treatment.

Results

In three UK centres 59 patients underwent peripheral nerve evaluation, with 46 (78 per cent) proceeding to permanent implantation. Of these 46 patients (40 women) all but two had improved continence at a median of 12 (range 1–72) months. Faecal incontinence improved from a median (range) of 7·5 (1–78) to 1 (0–39) episodes per week (P < 0·001). Urgency improved in all but five of 39 patients in whom ability to defer defaecation was determined, improving from a median of 1 (range 0–5) to 10 (range from 1 to more than 15) min (P < 0·001). Maximum anal squeeze pressure and sensory function to rectal distension changed significantly. Significant improvement occurred in general health (P = 0·024), mental health (P = 0·008), emotional role (P = 0·034), social function (P = 0·013) and vitality (P = 0·009) subscales of the Short Form 36 health survey questionnaire. There were no major complications. One implant was removed.

Conclusion

SNS is a safe and effective treatment, in the medium to long term, for faecal incontinence when conservative treatment has failed.
Development of symptoms and complications in individuals with asymptomatic gallstones
Authors: Halldestam I , Enell E-L , Kullman E , Borch K
Published: March 2004

Background

Gallbladder stones are common in the developed world. Complications of gallstones contribute substantially to healthcare costs and may be life threatening. The identification of individuals likely to develop complications would be of benefit in clinical practice as elective cholecystectomy could then be performed.

Methods

Seven hundred and thirty-nine subjects aged 35–85 years from the general population were screened for gallbladder problems by ultrasonography and questionnaire assessment of putative risk factors and digestive symptoms. Gallstones, cholesterolosis or sludge in the gallbladder were diagnosed in 123 (16·3 per cent) of 739 subjects, 120 of whom were followed for a median of 87 (range 3–146) months to May 2003 or until treatment was required.

Results

Fourteen patients were admitted to hospital and treated for gallstone-related complications or symptoms. The cumulative risk of being treated during the first 5 years after detection of asymptomatic gallstones was 7·6 per cent and there was no indication of this risk levelling off. There were no significant differences between treated and untreated subjects with regard to digestive symptoms or any of the risk factors monitored at the initial screening, although treated subjects were significantly younger than those who were not treated.

Conclusion

Nearly one in ten individuals with asymptomatic gallbladder stones in the general population may be expected to develop symptoms or complications that require treatment within 5 years. Age may be inversely related to the incidence of complications.
Comparison of three different procedures for antireflux surgery
Authors: Stewart G D , Watson A J M , Lamb P J , Lee A J , Krukowski Z H , Griffin S M , Paterson-Brown S
Published: March 2004

Background

No long-term comparisons of the various open and laparoscopic antireflux procedures have been undertaken. The aim of this study was to compare symptomatic outcomes of three procedures for antireflux surgery performed at three specialist units.

Methods

Patients undergoing open Nissen fundoplication, laparoscopic Nissen fundoplication and laparoscopic anterior partial fundoplication between December 1993 and February 2001 were identified. Patient outcome was assessed by means of a postal questionnaire. This was a hypothesis-generating study.

Results

Three hundred and fifty-seven patients (80·0 per cent) completed the questionnaire, with no differences in response rate between centres. Overall, a mean of only 7·6 per cent of patients reported a poor outcome. Logistic regression revealed no significant differences amongst the three procedures for any symptoms, after allowing for the effect of time. There was a general increase in the DeMeester score with increasing time from operation. The incidence of revisional reflux surgery was similar in the three groups.

Conclusion

Medium-term symptomatic outcome following all three procedures was similar. There was some recurrence of symptoms of gastro-oesophageal reflux with time for all procedures, suggesting that the effects of surgery diminish with time. The level of experience of the surgeon in a particular operation was more important than the procedure performed.