bluuebunny/crossref_metadata_2025 huggingface dataset:
The Influence of TiO2 Particle Size in TiO2/CuInS2 Nanocomposite Solar Cells
Authors: O'Hayre R. , Nanu M. , Schoonman J. , Goossens A. , Wang Q. , Grätzel M.
Published: June 2006

The recently developed CuInS2/TiO2 3D nanocomposite solar cell employs a three‐dimensional, or “bulk”, heterojunction to reduce the average minority charge‐carrier‐transport distance and thus improve device performance compared to a planar configuration. 3D nanocomposite solar‐cell performance is strongly influenced by the morphology of the TiO2 nanoparticulate matrix. To explore the effect of TiO2 morphology, a series of three nanocomposite solar‐cell devices are studied using 9, 50, and 300 nm TiO2 nanoparticles, respectively. The photovoltaic efficiency increases dramatically with increasing particle size, from 0.2 % for the 9 nm sample to 2.8 % for the 300 nm sample. Performance improvements are attributed primarily to greatly improved charge transport with increasing particle size. Other contributing factors may include increased photon absorption and improved interfacial characteristics in the larger‐particle‐size matrix.
Production and Potential of Bioactive Glass Nanofibers as a Next‐Generation Biomaterial
Authors: Kim H.‐W. , Kim H.‐E. , Knowles J. C.
Published: June 2006

Over the past decades, bioactive glass has played a central role in the bone regeneration field, due to its excellent bioactivity, osteoconductivity, and even osteoinductivity. Herein, exploitation of bioactive glass as a one‐dimensional nanoscale fiber by employing an electrospinning process based on a sol–gel precursor is reported for the first time. Under controlled processing conditions, continuous nanofibers have been generated successfully with variable diameters. The excellent bioactivity of the nanofiber is confirmed in vitro within a simulated body fluid by the rapid induction of bonelike minerals onto the nanofiber surface. The bone‐marrow‐derived cells are observed to attach and proliferate actively on the nanofiber mesh, and differentiate into osteoblastic cells with excellent osteogenic potential. The bioactive nanofibers have been further exploited in various forms, such as bundled filament, nanofibrous membrane, 3D macroporous scaffold, and nanocomposite with biopolymer, suggesting their versatility and potential applications in bone‐tissue engineering. Based on this study, the bioactive nanofibrous matrix is regarded as a promising next‐generation biomaterial in the bone‐regeneration field.
Cover Picture: Improving Organic Thin‐Film Transistor Performance through Solvent‐Vapor Annealing of Solution‐Processable Triethylsilylethynyl Anthradithiophene (Adv. Mater. 13/2006)
Authors: Dickey K. C. , Anthony J. E. , Loo Y.‐L.
Published: June 2006

In work reported by Loo and co‐workers on p. 1721, the current–voltage characteristics of triethylsilylethynyl anthradithiophene (TES ADT) thin‐film transistors are improved dramatically by a simple solvent‐vapor annealing process after device fabrication. Exposing the transistors to dichloroethane vapor induces structural rearrangement and crystallization of TES ADT, as shown on the cover (lower section, before annealing, upper section, after). The annealing results in drastic increases in on currents; the saturation mobility increases by two orders of magnitude and the current–voltage hysteresis is largely eliminated.
Cancer morbidity in iron and steel workers in Korea
Authors: Ahn Yeon‐Soon , Park Robert M. , Stayner Leslie , Kang Seong‐Kyu , Jang Jae‐Kil
Published: June 2006

Background

In the iron and steel industry, workers are potentially exposed to a number of carcinogens and are involved in a number of processes of a hazardous nature. The cancer morbidity of iron and steel workers from modern plants in a developing country is described.

Methods

Cancer morbidity at two Korean iron and steel complexes was analyzed using Poisson regression methods. Work histories were merged with the national cancer registry for 44,974 workers who were followed from 1988–2001.

Results

Four hundred sixty‐four cancers, in 1% of the population, were diagnosed over 14 years. Based on national cancer rates, the cohort exhibited a healthy worker effect for all cancer (SIR = 0.87, 95% CI = 0.79–0.95) reflecting relative good health, particularly for lung cancer (SIR = 0.58, 95% CI = 0. 04–0.82), stomach cancer (SIR = 0.78, 95% CI = 0.64–0.93), and liver cancer (SIR = 0.83, 95% CI = 0.68–1.01). Lung cancer morbidity was significantly elevated at the affiliated plants versus the parent plants (SRR = 2.35, 95% CI = 1.07–4.92), and all‐cancer morbidity was significantly elevated for maintenance workers compared to office and production workers (SRR = 1.27, 95% CI = 1.00–1.60). Lymphohematopoietic cancer incidence was higher in the coke plants (SRR = 3.46, 95% CI = 1.02–8.91) and stomach cancer incidence was higher in the maintenance departments (SRR = 1.66, 95% CI = 1.05–2.56).

Conclusions

This recent steelworker cohort exhibits possible excess cancer morbidity in some processing areas. Further follow‐up of this cohort and alternate study designs such as case‐control study will be needed to elucidate the relationship of exposure and health risks of iron and steel workers. Am. J. Ind. Med. 2006. Published 2006 Wiley‐Liss, Inc.
Worker participation in change processes in a Danish industrial setting
Authors: Rasmussen Kurt , Glasscock David J. , Hansen Ole N. , Carstensen Ole , Jepsen Jette F. , Nielsen Kent J.
Published: June 2006

Background

Improving the design, management and organization of work may be an important step in improving occupational health. An intervention, guided by the principles of participatory action research (PAR), is directed at traditional work environment problems in the epoxy plastic industry, that is, eczema and accident‐related injuries.

Methods

The study population consisted of employees at two wind turbine‐ manufacturing plants. A quasi‐experimental design was employed with before and after measurements and a comparison group with a 3½ year follow‐up period.

Results

The role of employee elected safety representatives was changed from one of controlling and “policing” to that of safety advisors. The attitudes of employees also changed, from an individualistic understanding of safety as the responsibility of the single employee, to a more collective understanding of safety as being everyone's shared responsibility. Structural changes led to a less hierarchical management system. This process led eventually to the establishment of self‐governing work groups in which each member had a well‐defined area of responsibility. The change process was associated with improvements in the psychosocial work environment and safety climate, a 66% reduction in the incidence of eczema, and a 48.6% reduction in the incidence of occupational accidents. In the comparison population, a twin factory under the same company, similar but delayed and less dramatic changes also occurred.

Conclusions

Implementation of a comprehensive intervention was followed by improved employee perceptions of the company's safety standards and the psychosocial work environment, as well as by substantial reductions in the incidence of eczema and occupational accidents. Am. J. Ind. Med. 2006. © 2006 Wiley‐Liss, Inc.
Organophosphorus pesticide urinary metabolite levels of children in farmworker households in eastern North Carolina
Authors: Arcury Thomas A. , Grzywacz Joseph G. , Davis Stephen W. , Barr Dana B. , Quandt Sara A.
Published: June 2006

Background

Organophosphorus (OP) pesticide urinary metabolite levels in a sample of farmworker children in North Carolina are documented and compared to national reference data. The relative importance of para‐occupational, residential, and environment risk factors are delineated.

Methods

Urine samples were collected from 60 farmworker children 1–6 years of age, and interviews were completed by their mothers. Urine samples were analyzed for the dialkylphosphate (DAP) metabolites of OP pesticides. Summed molar concentrations of the diethyl and dimethyl DAP metabolites provided summary measures.

Results

The farmworker children had relatively high levels of OP pesticide urinary metabolites compared to national reference data; for example, participating children had higher geometric means for diethylphosphate (DEP), diethylthiophosphate (DETP), and the summed diethyl metabolites. However, analyses found no pattern of significant associations between predictors and metabolite levels.

Conclusions

Future research requires greater precision in sampling and measurement to determine the risk factors for pesticide exposure among farmworker children. Am. J. Ind. Med. 2006. © 2006 Wiley‐Liss, Inc.
A computer system for coding occupation
Authors: Ossiander Eric M. , Milham Samuel
Published: June 2006

Background

Occupation information is widely used in epidemiologic studies and is collected on most death certificates and many birth certificates in the United States. Coding the massive amount of occupation information collected has been a challenge.

Methods

A simple word‐matching computer program to code occupation entries from vital records was developed. The accuracy of the program was evaluated by comparing its output to codes assigned by human coders.

Results

In routine use in the Washington State Department of Health (DOH), the computer system codes 96–97% of the occupation entries on birth and death records. It assigned the correct code on 89% (95% confidence interval (87%, 91%)) of the records it coded.

Conclusions

The occupation‐coding program is both efficient and accurate and can simplify the process of coding occupation entries from vital records. The system is adaptable and can be modified to use occupation classifications other than the one used by DOH. Am. J. Ind. Med. 2006. © 2006 Wiley‐Liss, Inc.
Asymmetric Heterogeneous Catalysis
Authors: Heitbaum Maja , Glorius Frank , Escher Iris
Published: June 2006

Limited natural resources and an increasing demand for enantiomerically pure compounds render catalysis and especially heterogeneous asymmetric catalysis a key technology. The field has rapidly advanced from the initial use of chiral biopolymers, such as silk, as a support for metal catalysts to the modern research areas. Mesoporous supports, noncovalent immobilization, metal–organic catalysts, chiral modifiers: many areas are rapidly evolving. This Review shows that these catalysts have more to them than facile separation or recycling. Better activities and selectivities can be obtained than with the homogeneous catalyst and novel, efficient reaction mechanisms can be employed. Especially fascinating is the outlook for highly ordered metal–organic catalysts that might allow a rational design, synthesis, and the unequivocal structural characterization to give tailor‐made catalysts.
Ozone‐induced grafting of a sulfoammonium zwitterionic polymer onto low‐density polyethylene film for improving hemocompatibility
Authors: Shan Bing , Yan Han , Shen Jian , Lin Sicong
Published: June 2006

Ozone‐induced grafting was developed to improve the hemocompatibility of biomaterials based on low‐density polyethylene (LDPE). An LDPE film was activated with ozone and graft‐polymerized with N,N′‐dimethyl(methacryloylethyl)ammonium propane sulfonate (DMAPS). The existence of sulfobetaine structures on the grafted film was confirmed by X‐ray photoelectron spectroscopy and attenuated total reflection/Fourier transform infrared (ATR–FTIR). More DMAPS was grafted onto the LDPE film as the DMAPS concentration increased, as determined by ATR–FTIR. Static contact‐angle measurements indicated that the DMAPS‐grafted LDPE film had a significant increase in hydrophilicity. The blood compatibility of the grafted film was preliminarily evaluated with a platelet‐rich‐plasma (PRP) adhesion study. No platelet adhesion was observed on the grafted film incubated with PRP at 37°C for 180 min. This new sulfoammonium zwitterionic‐structure‐grafted biomaterial might have potential for biomedical applications. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3697–3703, 2006
Nonisothermal crystallization kinetics of poly(ethylene terephthalate) and poly(methyl methacrylate) blends
Authors: Bishara Ahmed , Shaban Habib I.
Published: June 2006

The nonisothermal crystallization kinetics of poly(ethylene terephthalate) (PET) and poly(methyl methacrylate) (PMMA) blends were studied. Four compositions of the blends [PET 25/PMMA 75, PET 50/PMMA 50, PET 75/PMMA 25, and PET 90/PMMA 10 (w/w)] were melt‐blended for 1 h in a batch reactor at 275°C. Crystallization peaks of virgin PET and the four blends were obtained at cooling rates of 1°C, 2.5°C, 5°C, 10°C, 20°C, and 30°C/min, using a differential scanning calorimeter (DSC). A modified Avrami equation was used to analyze the nonisothermal data obtained. The Avrami parameters n, which denotes the nature of the crystal growth, and Zt, which represents the rate of crystallization, were evaluated for the four blends. The crystallization half‐life (t½) and maximum crystallization (tmax) times also were evaluated. The four blends and virgin polymers were characterized using a thermogravimetric analyzer (TGA), a wide‐angle X‐ray diffraction unit (WAXD), and a scanning electron microscope (SEM). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3565–3571, 2006
Living cationic polymerization of isobutyl vinyl ether (II): Photoinduced living cationic polymerization in a mixed solvent of toluene and diethyl ether
Authors: Kwon Soonhong , Lee Younsung , Jeon Hyunjeong , Han Kyuchan , Mah Soukil
Published: June 2006

A new method of preparation of living cationic polymer of isobutyl vinyl ether via photoinduced polymerization in the presence of diphenyliodonium iodide (DPII, initiator) and zinc iodide in a mixed solvent of toluene/diethyl ether, which was irradiated at −78°C for short period, was completed within 15 min. The reaction was allowed for further reaction in the dark until monomer was fully consumed. It was found that increase in the conversion of monomer to polymer during the irradiation is very limited. Confirmation of the linear dependence of number‐average molar mass of resulting polymer on % conversion together with the fact that polymerization proceeds until monomer consumption, and controllability of number‐average molar mass of resulting polymer, depending on the molar ratio of monomer and initiator, strongly suggests the living nature of this polymerization, unless reaction temperature becomes higher than 0°C, i.e., the absence of chain breaking process. The narrow molar mass distribution, whose polydispersity index values are less than 1.2, reveals that the rate of initiation where irradiation is usually completed within 15 min is much faster than that of propagation in cationic nature in this system. Effect of some major factors, such as solvent polarity and temperature, on the living nature of the polymerization was also investigated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3581–3586, 2006
Composites of poly(lactic acid) with flax fibers modified by interstitial polymerization
Authors: Shanks R. A. , Hodzic A. , Ridderhof D.
Published: June 2006

Natural fiber composites were designed and optimized to achieve good mechanical properties and resistance to growth of living organisms. Composite materials were prepared from poly(lactic acid) (PLA) with flax fibers, which had been subjected to interstitial polymerization to replace the water in the cellulose fibers. Prior to the polymerization, the flax fibers were extracted with sodium hydroxide and acetone to remove lignin, pectin, and waxes from the cellulose. Differential scanning calorimetry was used to study the crystallization and melting of the composites compared to pure PLA. The surface wetting of the fibers and morphology of the composites were studied by scanning electron microscopy and optical microscopy. Mechanical properties were studied using dynamic mechanical analysis. The influence of the interstitial polymerization on the dynamic storage modulus was found to be significant. The composites of polymerization treated flax with acetone washed fibers had higher storage moduli than the unwashed fiber composites, which suggested that the adhesion between the flax fibers and the matrix was improved by the treatments. The composites were subjected to moist environmental conditions in order to test for development of mold and fungi, and the acetone washed polymerization treated flax composites were resistant to these growths. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3620–3629, 2006
Poly(vinyl chloride)–green coconut fiber composites and their nonlinear viscoelastic behavior as examined with fourier transform rheometry
Authors: Leblanc Jean L.
Published: June 2006

Using a purposely modified torsional dynamic rheometer with a closed cavity, I investigated composites of poly(vinyl chloride) (PVC) and green coconut fibers (GCFs) with Fourier transform (FT) rheometry, a new dynamic test technique that resolves the complex dynamic response of materials submitted to harmonic strain into their main and harmonic components. Because of instrument limitations in the low‐strain region, torque signal harmonic components had to be corrected to yield results that suited established theoretical considerations. The preparation method of the composites had major effects on their linear and nonlinear viscoelastic responses; essentially, no homogeneous material could be prepared by dry blending plus extrusion, in contrast to dry blending plus mixing, which is the recommended technique; this was likely because PVC plasticization was then achieved. One of the most important rheological characteristics of the PVC–GCF composites was the quasidisappearance of the linear viscoelastic behavior. Nevertheless, an easy extrapolation technique was used to extract linear modulus data from the FT results, which led me to the conclusion that the reinforcing effect of the GCFs was essentially hydrodynamic with little, if any, interfacial interaction between the polymer matrix and the fibers. The results gathered from nonlinear viscoelastic properties, as obtained through FT rheometry, supplement this conclusion. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3638–3651, 2006
Evaluation of the shrinking‐core model for examining the kinetics of film formation in a reactive latex blend
Authors: Boyars Brian , Daniels Eric S. , Klein Andrew
Published: June 2006

We prepared reactive latex blends from two copolymer latices comprised of n‐butyl methacrylate (n‐BMA) with acetoacetoxyethyl methacrylate and n‐BMA/dimethylaminoethyl methacrylate to study the kinetics of film formation. We generated thin films by blending equal weights of the two latices. The films were then cured at temperatures ranging from 50 to 90°C. The extent of the crosslinking reaction was calculated from the crosslink density, which was determined from swelling measurements of the films in toluene. The shrinking‐core model, a diffusion/reaction model, which was originally derived for combustion reactions of coal particles, was adopted to calculate the diffusion coefficient (De) and reaction rate constants from the extent of the reaction with time data. This model system exhibited a diffusion‐controlled regime above 70°C and a reaction‐controlled regime at temperatures below 70°C. In the reaction‐controlled regime, the shrinking‐core model predicted De for the system, which was in agreement with literature values for n‐BMA. In the diffusion‐controlled regime, the model predicted a lower apparent value for De but with an activation energy that was close to that obtained for n‐BMA. The model was also used to examine the kinetics of the crosslinking reaction. The kinetic rate constants for the crosslinking reaction were also determined. The activation energy for the crosslinking reaction was 18.8 kcal/mol, which compared reasonably with the activation energy of 22.8 kcal/mol determined for the reaction between the functional monomers as small molecules. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3659–3665, 2006
Use of trifluoromethanesulfonic acid as catalyst for the cyclization of polyisoprene
Authors: Chan Cheng‐Kuang , Lin Chia‐Ying
Published: June 2006

In this study, trifluoromethanesulfonic acid was employed as catalyst for the cyclization of polyisoprene. From 1H nuclear magnetic resonance spectroscopy and gel permeation chromatography investigations, cyclization was confirmed, and the molecular structure variation of polyisoprene during cyclization reaction was determined. With the comparison to that catalyzed by other strong acids (methanesulfonic acid), polyisoprene was cyclized with much higher efficiency, using trifluoromethanesulfonic acid as catalyst. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3666–3669, 2006
Stabilization of polymers of vinylchloride with sulfur
Authors: Akhmetkhanov Rinat M. , Kabalnova Natalya N. , Akhmetkhanov Ruslan R. , Kolesov Sergey V. , Zaikov Gennadi E.
Published: June 2006

The high stabilizing efficiency of element sulfur was revealed by the thermooxidative destruction of polymers of vinylchloride (VC). It was shown that the stabilizing efficiency of sulfur in compositions of polymers of VC is comparable with the efficiency of phenolic antioxidants. Element sulfur inhibits process of autooxidation of esters‐plastifiers of polymers of VC, apparently, because of destruction of formed hydroperoxides. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4538–4542, 2006
Study of nucleation activity and application of a nucleating agent to copolypropylene
Authors: Tu Zhigang , Mai Kancheng , Wu Zengqing
Published: June 2006

The influences of nucleating agent content on crystallization peak temperature, crystallization curve shape, crystallization onset temperature, and crystallinity of a copolypropylene were studied in detail by differential scanning calorimetry. The results showed that crystallization onset temperature and crystallization peak temperature increased 17°C–22°C and 15°C–19°C, respectively, with increasing nucleating agent content. The behavior of the nucleating agent showed excellent efficiency. But the shape of the crystallization curve broadened with increasing nucleating agent content, and the crystallinity came to an extremum when the nucleating agent content was 0.2%. These results generally differed from those for crystallization of i‐PP by a nucleating agent. Modification of copolypropylene was studied by use of a nucleating agent, and the characteristics of the effects of the nucleating agent on copolypropylene were mastered. The results showed that the hardness of a copolypropylene improved observably. So the abrasion resistance of biaxially oriented polypropylene (BOPP) film for cigarette packaging was improved by adopting the modified copolypropylene as the skin‐layer heat‐seal material of BOPP film. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101:3915–3919, 2006
Hybrid acrylic–polyurethane latexes: Emulsion versus miniemulsion polymerization
Authors: Wang Chunpeng , Chu Fuxiang , Guyot Alain , Gauthier Catherine , Boisson Fernande
Published: June 2006

Two kinds of hybrid acrylic–polyurethane (PUA) latexes are compared according to their synthesis and properties. The acrylic part is a copolymer of styrene, methyl methacrylate, and butyl acrylate. The PUAs are based on the polycondensation of isophorone diisocyanate and poly(propylene glycol) using butanediol and ethylene diamine as chain extenders. The first class result from the polymerization of miniemulsions of solutions of PU in the mixture of monomers using benzoyl peroxide as an initiator at 80°C. In the second class PUs modified by neutralized dimethylolpropionic acid are used as seeds and emulsifiers for emulsion polymerization of the monomer mixtures initiated with azobisisobutyronitrile at 75°C. The polymerization kinetics are compared, as well as the morphology of the latex particles. Films are obtained upon coalescence of these latexes, and the surface composition of these films and their tensile properties are studied. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3927–3941, 2006
A thermodynamic study of the binding of human serum albumin onto N,N′‐diethylaminoethyl dextran microbeads
Authors: Kaplan Can Hatice , Güner Ali
Published: June 2006

Adsorption of proteins on solid surfaces is widely studied because of its importance in various biotechnological, medical, and technical applications, e.g., biosensors, cardiovascular implants, and chromatography. Adsorption thermodynamics has been studied on the microbeads of N,N′‐diethylaminoethyl (DEAE) Dextran anion exchanger for the human serum albumin (HSA) at 25, 30, 35, 40, and 45°C. As a result, some thermodynamic parameters like Freundlich constants, thermodynamic equilibrium constant (KD), standard free energy changes (ΔGassoc), standard entropy changes (ΔSassoc), and standard enthalpy change (ΔHassoc) have been evaluated. Using the linear Van't Hoff plot, ΔHassoc value of the system for the interaction of bovine serum albumin (BSA)‐adsorbed crosslinked DEAE dextran microbeads was determined as 20.650 kJ/mol. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3942–3947, 2006
Antimicrobial, mechanical, barrier, and thermal properties of starch–casein based, neem (Melia azardirachta) extract containing film
Authors: Jagannath J. H. , Radhika M. , Nanjappa C. , Murali H. S. , Bawa A. S.
Published: June 2006

The Starch–Casein‐based edible films containing with or without neem (Melia azadirachta) extract was prepared. The neem based free films were also heat pressed and all of them were assessed for inhibition of pathogenic organisms namely E. coli, Staphylococcus aureus, Bacillus cereus, Listeria monocytogenes, Pseudomonas spp., and Salmonella, using disc diffusion assay. The Glass‐transition temperature (Tg) and thermal properties of the films were determined with the help of DSC and DMA. Tensile strength (TS), elongation at break (EAB), water vapor transmission rate (WVTR), and oxygen transmission rate (OTR) of the films were also determined. Incorporation of neem extract to edible film did not affect any of the physical properties except microbial, and the films were effective in inhibiting the growth of pathogens, since the inhibition zones varied from 15 mm as large as 24 mm. However, the heat‐pressed films containing neem extract led higher the Tg, TS, and modulus, while the EAB was marginally affected, indicating the toughening of the film and as expected, the heat pressing of films decreased the WVTR and marginally affected OTR. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3948–3954, 2006
Effect of various environmental conditions on the swelling property of PAAm/PAAcK superabsorbent hydrogel prepared by ionizing radiation
Authors: Abd El‐Rehim H. A. , Hegazy El‐Sayed A. , Abd El‐Mohdy H. L.
Published: June 2006

Polyacrylamide/potassium polyacrylate (PAAm/PAAcK) superabsorbent hydrogels were prepared by using ionizing radiation for possible use in agricultural purposes. The influence of environmental conditions such as water quality, fertilizer salts, soil pH, and surrounding temperature on PAAm/PAAcK water absorbency and retention was investigated. The water absorbency apparently decreased with an increase in the valence and ionic strength of the salt solutions. The swelling of PAAm/PAAcK immersed in the solutions containing fertilizer of different nitrogen sources followed the order: Urea > NH4NO3 > (NH4)2SO4. The PAAm/PAAcK water absorbency in solutions containing different types of phosphate sources was in the order: H3PO4 > KH2PO4 > K2HPO4. However, the water absorbency of PAAm/PAAcK in the solution of different types of potassium salts followed the order: KCl > K2SO4 > K2HPO4. PAAm/PAAcK hydrogel is fully swollen at pH 6. The relation between the ability of PAAm/PAAcK to retain water against time at different temperatures was studied. As the environmental temperature increases, the water retention of PAAm/PAAcK decreases. Potential application of PAAm/PAAcK in agriculture was evaluated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3955–3962, 2006
Study on the morphology of the novel hydrophobically associative acrylamide‐based terpolymer in aqueous solution by AFM measurements
Authors: Zhong Chuanrong , Huang Ronghua , Ye Lin , Dai Hua
Published: June 2006

The synthesized hydrophobically associating water‐soluble polymer P(AM‐BST‐NaAMPS) (PASA) exhibits good viscosification properties in the aqueous and brine solution. To study the viscosifying mechanisms of the polymer in the aqueous solution and brine solution, atomic force microscope (AFM) was applied to observe the micromorphology of the polymer solution. The AFM measurements show that continuous network structures have been formed in the aqueous solution of 0.05 g dL−1 PASA, and with the increase in PASA concentration, the network structures become much bigger and more condensed. The network structures of PASA are collapsed by the addition of salt, and tree‐like crystals are formed, leading to the decrease in the apparent viscosity of PASA solution. However, by increasing the NaCl concentration or the polymer concentration in the brine solution, the sizes of crystals increase. These results are consistent with the ESEM and viscosity study results. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3996–4002, 2006
Transformation of vulcanized natural rubber into lower molecular weight polymers and their application to grafted copolymer synthesis with some vinyl monomers
Authors: Yamazaki Hiroki , Nagasawa Tomomi , Choi Wonmun , Endo Takeshi
Published: June 2006

Graft copolymerization of several vinyl monomers onto polyisoprene was carried out to explore the possibility to recycle waste rubber to useful functional materials. Synthetic polyisoprene, vulcanized natural rubber, and vulcanized natural rubber with carbon black were converted to lower molecular weight polymers at 300°C, under air or nitrogen atmosphere. The obtained low molecular weight natural rubber and polyisoprene were soluble in organic solvents, such as hexane, toluene, tetrahydrofuran (THF), chloroform, and monochlorobenzene. Radical copolymerization of styrene with a thermally fragmented natural rubber was carried out at 80°C in bulk for 2 h in the presence of 2,2′‐azobis(isobutyronitrile) (AIBN) under air atmosphere to give the corresponding grafted copolymer. The obtained polymer was a beige powdery copolymer at room temperature and consisted of isoprene (38 mol %) and styrene (62 mol %) units, respectively. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4003–4010, 2006
Curing of epoxy resin with poly(m‐phenylene methylphosphonate)
Authors: Wu Tao , Piotrowski Andrew M. , Yao Qiang , Levchik Sergei V.
Published: June 2006

The mechanism and kinetics of curing of epoxy resin with poly(m‐phenylene methylphosphonate) (PMP) was studied by extraction and swelling experiments, DSC, 31P NMR, and FTIR. It was shown that at linear heating of 20°C/min PMP cures bisphenol A type epoxy resin at 230–300°C, whereas in the presence of catalytic amount of 2‐methyl imidazole the curing occurs at 200–230°C. Under isothermal conditions, epoxy resin was cured with PMP after 40–70 min at 150°C. An unusual mechanism of curing due to opening and insertion of epoxy into the phosphonate bond was suggested. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4011–4022, 2006
Study on the synthesis of thiirane
Authors: Li Yafeng , Cheng Jue , Zhang Junying
Published: June 2006

In this study, a thiirane resin was synthesized by the reaction of corresponding epoxy resin with KSCN. The synthetic conditions influencing the conversion of epoxy group were systematically investigated, such as the reaction temperature, reaction media, reaction time and the ratio of KSCN to epoxy group. It was found that the conversion of epoxy group increased with the increasing reaction temperature, improving the solubility of the mediate, extending reaction time, and the enhancing ratio of salt (KSCN) to epoxy group. Wherein, the reaction temperature and the ratio of the KSCN to epoxy group were more effective. For example, when the molar ratio of KSCN to epoxy group was equal to 2.0, the conversion of epoxy group got the maximum value, 0.65. In addition, the hot plate method was used to measure the gelling time of the resultant thiirane resin at different temperatures. It was found that the gelling time was reduced to 47–85% times as the corresponding epoxy resin depending on the conversion of the epoxy group, and the curing activation energy was diminished from 39 kJ/mol of epoxy resin to 17 kJ/mol. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4023–4027, 2006
Surface characterization of hollow fiber membranes used in artificial kidney
Authors: Rafat Mehrdad , De Dibyendu , Khulbe K. C. , Nguyen Thanh , Matsuura Takeshi
Published: June 2006

The internal and external curved surfaces of polysulfone hollow fiber membranes were characterized by atomic force microscopy (AFM), contact angle measurement (CAM), and scanning electron microscopy (SEM) with the aim of improving the membrane surface properties for blood compatibility. Novel approaches were applied to evaluate a number of properties, including the roughness, pore size, nodule size, and wettability of the surfaces of the hollow fibers. CAM studies were carried out by directly observing the liquid meniscus at the surfaces of hollow fibers. Observation of the meniscus and measurement of the contact angle became possible by using an imaging system developed in our laboratory. AFM and SEM studies were also conducted on the surfaces of the hollow fiber membranes by cutting them at an inclined angle. The effect of the molecular weight of poly(ethylene glycol) (PEG) in the polymer blend on the surface properties of the hollow fibers was studied. Increasing the PEG molecular weight increased the average pore size whereas it decreased the contact angle. The contact angle depended on the microscopic surface morphology, including nodule size and roughness parameters. The theoretical prediction along with the experimental data showed that the measured contact angle would be greater than the value intrinsic to the membrane material because of the formation of composite surface structures. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4386–4400, 2006
Phase transition and domain morphology of siloxane‐containing hard‐segmented polyurethane copolymers
Authors: Tsen W. C. , Chuang F. S.
Published: June 2006

The phase transitions and the morphology of hard‐segment domains of those siloxane‐containing hard‐segmented polyurethane copolymers are studied by differential scanning calorimetry (DSC). The NH‐SiPU2 copolymer, which comprises a siloxane–urea hard segment and a polytetramethylene ether glycol soft segment (PTMG2000), exhibits a high degree of phase‐separation and a highly amorphous structure. Therefore, NH‐SiPU2 copolymer proceeds with a melt‐quenching process and with various annealing conditions, to examine the morphologies and the endothermic behaviors of the siloxane‐containing hard‐segment domains. DSC thermograms of further annealed NH‐SiPU2 indicate that the first endotherm (T1) at around 75°C is related to the short‐range ordering of amorphous siloxane hard‐segment domains (Region I), and the second endotherm (T2) at around 160°C is related to the long‐range ordering of amorphous siloxane hard‐segment domains (Region II). The DSC thermograms at annealing temperatures below and above T1 demonstrate that both the temperature and the enthalpy of T1 linearly increase with the logarithmic annealing time (log ta). This result shows that the endothermic behavior of T1 is typical of enthalpy relaxation, which is caused by the physical aging of the amorphous siloxane hard segment. Additionally, the siloxane hard segments in Region I are movable, and can merge with the more stable Region II under suitable annealing conditions. Transmission electron microscopy shows that Regions I and II are around 200 and 800 nm wide, and that the Region I can be combined with the stable Region II, under suitable annealing conditions. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4242–4252, 2006
Synthesis and properties of epoxies containing rigid rods in the side chains
Authors: Hsieh K. H. , Ji S. B. , Wang H. R. , Ho G. H. , Han J. L.
Published: June 2006

A novel epoxy containing rigid rods in the side chain (SR‐epoxy) was synthesized by bulk polymerization. The SR‐epoxy resins were characterized by Fourier transform infrared. The cured SR‐epoxies showed excellent mechanical properties and high thermal stabilities. Scanning electron microscopy (SEM) of the cured SR‐epoxy illustrated a fiber‐like morphology. The thermal properties, dynamic mechanical properties, compatibility, and morphology of the SR‐epoxies were extensively investigated in the study. SEM photographs showed that there were some fiber‐like structures in the system of the SR‐epoxy containing the rigid‐rod group 4,4′‐bis(6‐hydroxyhexoxy) biphenyl, which formed a self‐reinforcing composite. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4030–4036, 2006
Influence of diffusive processes on the formation of an interfacial layer in carbon plastics based on phenylone
Authors: Kozlov G. V. , Burya A. I. , Dolbin I. V. , Zaikov G. E.
Published: June 2006

The influence of the interfacial layer structure on the intensity of diffusive processes during their formation was shown. An increase in the fractal dimension of this layer structure, which was due to macromolecular coils drawing on the smooth surface of the fiber, was determined by a transition from fast diffusion to slow. This factor was controlled by both the thickness of the interfacial layer and its strength. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4044–4047, 2006
Use of an epoxidized oil‐based resin as matrix in vegetable fibers‐reinforced composites
Authors: Boquillon Nicolas
Published: June 2006

Hemp fibers were used as natural reinforcement in composites of thermosetting vegetal oil based resin. Boards with fibers content from 0 to 65 vol % were produced by hot pressing. The mechanical properties were investigated with flexural testing. The effect of effect has been observed on both modulus and strength, indicating a good fiber–matrix interfacial adhesion, which was confirmed by means of scanning electron microscopy observations. Dynamic mechanical analysis also showed an important reinforcement effect in the polymer rubbery region, where at 180°C the storage modulus increased from 17 MPa for the neat resin to 850 MPa for 65 vol % fiber content composites. It also revealed an glass transition temperature decrease when fiber amount in the composite increased. Additional experiments based on differential scanning calorimetry show a weakly accelerated cure when fibers content increases, which usually lead to a lower Tg. But, this phenomenon alone cannot explain the observed Tg change. Contact angle on hemp evolution with time for the resin components show that anhydride is totally absorbed after a few seconds, whereas contact angle of epoxydized oil decreases slowly. This indicates probably a preferential anhydride absorption that leads to a lower amount of anhydride in the matrix and as a consequence to a reduced Tg. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4037–4043, 2006
Fast response single‐ion transport light‐emitting electrochemical cell based on PPV derivative
Authors: Kong F. , Zhang S. Y. , Zheng Y. , Ou C. G. , Yang C. Z. , Yuan R. K.
Published: June 2006

We present the electrical and optical characteristics of a single‐ion transport light‐emitting electrochemical cell (SLEC) based on poly(p‐phenylene vinylene) (PPV) derivative containing aryl‐substituted oxadiazole in the backbone (MEH‐OPPV). Ionized polyurethane–poly(ethylene glycol) (PUI) used as polymer electrolyte is introduced into the active layer of the SLEC. The turn‐on voltage of the SLEC is about 3 V according to its current density–voltage (J–V) characteristics. The response time of the SLEC is less than 10 ms, lower than that of normal LECs by two orders of magnitudes roughly. The reasons of the quick response for the SLEC are discussed in the article. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4253–4255, 2006
Dichlorocarbene modification of natural rubber and its role as a modifier in blends of natural rubber and hydrogenated nitrile rubber
Authors: Elizabeth Kulangara I. , Alex Rosamma , Kuriakose Baby , Varghese Siby , Peethambaran Nedumpalliparampil R.
Published: June 2006

Dichlorocarbene modification of natural rubber (NR) carried out by alkaline hydrolysis of chloroform in presence of cetyl trimethyl ammonium bromide as phase‐transfer catalyst was investigated. Extent of chemical reaction was characterized by estimation of chlorine content and FTIR studies. Rate of dichlorocarbene addition depends on the time and temperature of reaction. Reaction carried out at 60°C for 2 h yielded a material with a chlorine content of 15%. Chemical modification of NR was accompanied by introduction of chlorine through cyclopropyl ring to the main chain of NR as revealed from FTIR studies. As level of chlorination increased, the physical nature of NR changed from a soft flexible state to a hard nontacky form. Blends of NR with hydrogenated nitrile rubber (HNBR) containing three to seven parts of dichlorocarbene‐modified NR (DCNR) of chlorine content 15% could be prepared by conventional mill mixing. Incorporation of DCNR into blends of NR and HNBR promoted polar interaction between the chlorine segments and acrylonitrile segments of the blend as shown from the shift in characteristic IR absorption peaks and shift in Tg from DSC studies. As a consequence, DCNR acted as an interface modifier in blends of NR and HNBR. Blends of NR and HNBR containing DCNR showed a considerable improvement in cure behavior, physical properties, and ageing characteristics in oil, ozone, and high temperature compared to pure blends of NR and HNBR. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4401–4409, 2006
Vinyl ethers with polysulfide and hydroxyl functions and polymers therefrom as binders for lithium–sulfur batteries
Authors: Trofimov B. A. , Morozova L. V. , Markova M. V. , Mikhaleva A. I. , Myachina G. F. , Tatarinova I. V. , Skotheim T. A.
Published: June 2006

Bis‐[3‐(vinyloxyethoxy)‐2‐hydroxypropyl‐]polysulfides (BVPS) have been prepared by reacting ethylene glycol vinyl glycidyl ether (EGVGE) with Na2S4 in the presence of NaHCO3 and a phase transfer catalyst, triethylbenzylammonium chloride. The polysulfides obtained are inactive in radical polymerization but polymerize readily upon thermal initiation (140°C, 1 h) or in the presence of cationic catalysts [BF3·OEt2, CF3COOH, H(AuCl4)·4H2O, LiBF4‐dimethoxyethane, 20–70°C]. Polymerization leads to the formation of crosslinked polymers. It has been shown that BVPS and their polymers can be used as active binders in cathode compositions of lithium–sulfur power sources. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4051–4055, 2006
Preparation of poly(vinyl acetate) microspheres with narrow particle size distributions by low temperature suspension polymerization of vinyl acetate
Authors: Lee Se Geun , Kim Jae Pil , Kwon Ick Chan , Shin Dong Soo , Han Sung Soo , Lyoo Won Seok
Published: June 2006

To estimate influences of suspension polymerization conditions including conversion, polymerization temperature, stirring rate, initiator concentration, monomer concentration, and suspending agent concentration on the volume average diameter (Davg) and particle size distribution (PSD) of poly(vinyl acetate) (PVAc) microspheres, vinyl acetate (VAc) was suspension‐polymerized at low temperature using 2,2′‐azobis(2,4‐dimethylvaleronitrile) as an initiator. The effects of each condition, on Davg of PVAc microspheres, were expressed as follows, Davg = [conversion]a[temperature]b[rpm]c[ADMVN]d[VAc]f [suspending agent]g. Logarithms of Davg were linearly proportional to those of polymerization conditions, and their exponents, a, b, c, d, f, and g were calculated as 0.27, −13.7, −1.37, −0.21, 0.58, and 0.29, respectively. Variations of PSDs, according to polymerization conditions, were examined by considering polymerization rate, droplet or suspension viscosity, and droplet break‐up/coagulation equilibrium. From these results, PVAc microspheres with various sizes and narrow PSDs were obtained effectively under carefully controlled polymerization conditions, which can be used as promising precursors of novel PVA microspheres through heterogeneous surface saponification. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4064–4070, 2006
Epoxy/alumina nanoparticle composites. II. Influence of silane coupling agent treatment on mechanical performance and wear resistance
Authors: Vassileva E. , Friedrich K.
Published: June 2006

Two silane coupling agents (SCAs) were used to treat alumina nanoparticles to improve nanoparticle dispersion into the polymer matrix. [3‐(2‐Aminoethylamino)‐propyl]‐trimethoxysilane [a reactive silane coupling agent (RSCA)] was able to form covalent bonds with both the reinforcing agent (alumina nanoparticles) and the epoxy matrix, whereas 3‐(trimethoxysilyl) propyl methacrylate (a nonreactive SCA) could not covalently interact with the epoxy resin. The strengthening of the filler–matrix interactions by means of covalent bonds resulted in improved flexural strength, strain, and especially, wear resistance. The wear rate and the weight loss of the RSCA‐treated alumina nanoparticle composite were the best among the investigated composite samples and equal to these of the neat epoxy matrix. This improvement was due to better nanoparticle dispersion, a result of the SCA treatment of the alumina nanoparticles. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4410–4417, 2006
Influence of irradiation crosslinking on time dependences of conduction and self‐heating in acetylene carbon black filled high‐density polyethylene composites
Authors: Song Yihu , Zheng Qiang
Published: June 2006

The time dependences of electrical conduction and self‐heating in high‐density polyethylene/acetylene carbon black composites crosslinked with electron beam irradiation at three different dosages are studied in relation to voltage and ambient temperature. The characteristic decay current constant (τi) and the exponential growth time constant for self‐heating (τg) are determined for the samples under voltages (U) above the onset voltage (Uc) of self‐heating. The influence of crosslinking on the current decay dynamics, self‐heating process, and amplitude of the resistance switching under field action are discussed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4418–4422, 2006
Characterization and preparation of new multiwall carbon nanotube/conducting polymer composites by in situ polymerization
Authors: Md Showkat Ali , Lee Kwang‐Pill , Iyengar Gopalan Anantha , Kim Sang‐Ho , Choi Seong‐Ho , Sohn Sang‐Ho
Published: June 2006

Composites based on poly(diphenyl amine) (PDPA) and multiwall carbon nanotubes (MWNTs) were prepared by chemical oxidative polymerization through two different approaches: in situ polymerization and intimate mixing. In in situ polymerization, DPA was polymerized in the presence of dispersed MWNTs in sulfuric acid medium for different molar composition ratios of MWNT and DPA. Intimate mixing of synthesized PDPA with MWNT was also used for the preparation of PDPA/MWNT composites. Transmission electron microscopy revealed that the diameter of the tubular structure for the composite was 10–20 nm higher than the diameter of pure MWNT. Scanning electron microscopy provided evidence for the differences in the morphology between the MWNTs and the composites. Raman and Fourier transform IR (FTIR) spectroscopy, thermogravimetric analysis, X‐ray diffraction, and UV–visible spectroscopy were used to characterize the composites and reveal the differences in the molecular level interactions between the components in the composites. The Raman and FTIR spectral results revealed doping‐type molecular interactions and coordinate covalent‐type interactions between MWNT and PDPA in the composite prepared by in situ polymerization and intimate mixing, respectively. The backbone structure of PDPA in the composite decomposed at a higher temperature (>340°C) than the pristine PDPA (∼300°C). This behavior also favored the molecular level interactions between MWNT and PDPA in the composite. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3721–3729, 2006