bluuebunny/crossref_metadata_2025 huggingface dataset:
Physician Variability in History Taking When Evaluating Patients Presenting with Chest Pain in the Emergency Department
Authors: James Thea L. , Feldman James , Mehta Supriya D.
Published: January 2006

Objectives:
The goal of this study was to examine how physicians in the emergency department ask questions of patients presenting with chest pain and whether this varies by patient demographics.

Methods:
This was a cross‐sectional study with convenience sampling. A survey was administered to adult emergency department patients presenting with chest pain after emergency physicians obtained the history and performed the physical examination. No identifying data were collected from the patients. In addition to demographics, patients were asked whether or not their physician asked them about factors related to coronary syndrome and myocardial infarction etiology.

Results:
A total of 308 of 332 patients (93%) participated. Patients had a mean age of 52 years, 54% were male, and 85% spoke English; classification by race was 31% African American, 28% white, 19% Hispanic, and 13% other. History taking did not differ by gender. Patients who reported being asked about the following were statistically significantly younger than those who reported not being asked: family history, other medical problems, smoking, cocaine use, and alcohol use. Nonwhite patients reported being asked about the following more frequently than white patients: smoking (94% vs. 84%), alcohol use (81% vs. 70%), and cocaine use (64% vs. 42%). In multivariate logistic regression controlling for age, nonwhite patients were more likely than white patients to be asked about smoking (odds ratio [OR], 2.79; 95% confidence interval [CI] = 1.26 to 6.19), cocaine use (OR, 2.49; 95% CI = 1.50 to 4.12), and alcohol use (OR, 1.77; 95% CI = 1.0 to 3.09).

Conclusions:
The variability in questions about behavioral factors associated with chest pain etiology as reported by patients may indicate a possible cultural bias by physicians. Differences in risk identification may lead to differences in treatment decisions.
Intralipid Prolongs Survival in a Rat Model of Verapamil Toxicity
Authors: Tebbutt Simon , Harvey Martyn , Nicholson Tonia , Cave Grant
Published: January 2006

Objectives:
Verapamil is a lipid‐soluble calcium channel blocker with significant mortality in overdose. Previous investigators have demonstrated the benefit of lipid emulsion therapy in ameliorating toxicity from lipid‐soluble agents. The authors investigated the effect of Intralipid treatment in a rat model of verapamil toxicity.

Methods:
Thirty sedated Wistar rats were infused with verapamil at 37.5 mg/kg/h. Five minutes after the start of infusion, animals were treated with a bolus of either 12.4 mL/kg 20% Intralipid or 12.4 mL/kg 0.9% saline. Verapamil infusion was continued until the animals were killed. Respiratory rate, heart rate, and electrocardiography were sampled every 2.5 minutes throughout.

Results:
Survival was prolonged in the Intralipid‐treated group (44 ± 21 vs. 24 ± 9 minutes; p = 0.003). The median lethal dose was increased in the Intralipid group (25.7 mg/kg [95% confidence interval {CI} = 24.7 to 26.7] vs. 13.6 mg/kg [95% CI = 12.2 to 15.0]). A less marked decrease in heart rate was observed during verapamil infusion in the Intralipid‐treated group (6.8 beats/min [95% CI = 8.3 to 5.2] for Intralipid vs. 10.7 beats/min [95% CI = 12.6 to 8.9] for saline; p = 0.001).

Conclusions:
Intralipid treatment prolongs survival and doubles median lethal dose in a rat model of verapamil toxicity. The mechanism of action remains to be elucidated.
Determination of SMN1/SMN2 Gene Dosage by a Quantitative Genotyping Platform Combining Capillary Electrophoresis and MALDI-TOF Mass Spectrometry
Authors: Kao Hung-Yi , Su Yi-Ning , Liao Hsin-Kai , Liu Ming S , Chen Yu-Ju
Published: January 2006

Background: Spinal muscular atrophy (SMA) is a common inherited and fatal neuromuscular disease caused by deletions and/or mutations that lead to altered concentrations of proteins encoded by the survival motor neuron genes SMN1 and SMN2. Because of the high incidence (at least 1 in 10 000 live births and a carrier frequency of 1 in 35 to 1 in 50) and severity of the disease, precise quantification of SMN1 and SMN2 gene copy numbers is essential for diagnosis and genetic counseling.

Methods: We developed a genotyping platform combining capillary electrophoresis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) to quantify absolute gene dosage. The absolute gene dosage can be determined by a multiplexed competitive PCR protocol followed by capillary electrophoresis analysis. The relative SMN1/SMN2 ratio can be analyzed by PinPoint assay followed by MALDI-TOF MS analysis.

Results: The complementary assays were evaluated in confirmed cases including 9 affected patients, 33 carriers, and 478 healthy individuals from the general population. We were able to determine all genotypes with different SMN1/SMN2 gene copy number ratios, which unambiguously diagnosed carrier status and the severity of SMA with 100% specificity.

Conclusions: This quantitative genotyping platform is suitable for detection of SMA. The described approach may serve as a general quantitative genotyping method for molecular diagnosis of other inheritable diseases.
Spawning Demographics and Juvenile Dispersal of an Adfluvial Bull Trout Population in Trestle Creek, Idaho
Authors: Downs Christopher C. , Horan Dona , Morgan-Harris Erin , Jakubowski Robert
Published: January 2006

We utilized a screw trap, trap-box weir, remote passive integrated transponder tag (PIT) detection weir, and otolith microchemistry to evaluate (2000–2004) spawning demographics and migration patterns of adfluvial bull trout Salvelinus confluentus in Trestle Creek, Idaho, a tributary to Lake Pend Oreille. Annual repeat spawning was more common than alternate-year spawning. Annual growth, estimated from adult bull trout PIT-tagged in 2000 and recaptured in 2001, averaged 28 mm. Peak diel movement of adult bull trout occurred after sunset. Emigration of juveniles occurred in two pulses, one in spring that was associated with snowmelt runoff and increasing water temperatures and a second in fall as stream temperatures dropped and fall rains began. Juvenile bull trout moved a mean rate of 455 m per night in 2001 and 423 m per night in 2002. Each year we trapped large numbers of age-0 bull trout that appeared to be emigrating with high spring flows. Based on otolith microchemistry, most of the 47 adults in the sample had emigrated at age 3 or age 4, and none had emigrated at age 0. This suggests that age-0 emigrants are not making a significant contribution to adult returns.
Growth, Movement, and Catch of Brook, Rainbow, and Brown Trout after Stocking into a Large, Marginally Suitable Adirondack River
Authors: Baird Owen E. , Krueger Charles C. , Josephson Daniel C.
Published: January 2006

Poststocking growth, movement, and catch were compared among hatchery brook trout Salvelinus fontinalis, rainbow trout Oncorhynchus mykiss, and brown trout Salmo trutta in a fifth-order river. Associations of species, size, and stocking date with angler catch were also examined. The river is episodically acidified, and during summer it approaches lethal maximum temperatures for trout. Catchable-sized brook and rainbow trout (168–458 mm total length) were stocked in the late spring of 1996 and 1997. Brown trout were stocked only in 1997. Fish were marked with visible implant tags and were recovered through October of each year. All three species had negative daily growth rates in weight over the summer and early fall. Rainbow trout stocked in 1997 tended to move downstream after stocking, whereas the other groups showed no strong movement trend. Recovery rates significantly differed between brook and brown trouts stocked in early June and those fish stocked in late May. Large (>300-mm) rainbow trout were caught at higher rates than small (<260-mm) fish were. Anglers were estimated to have caught 72% of the stocked brook trout, 51% of the rainbow trout, and 18% of the brown trout. High summer water temperatures (>20°C) did not affect angler catch rates because cool refuges within the river concentrated and made the stocked fish—especially brook trout—vulnerable to angling. By stocking more than one species, we were able to create diversified angling opportunities and sustain a fishery in this thermally marginal river over the entire summer season.
The Theme of Educational Transfer in Comparative Education: A View over Time
Authors: Beech Jason
Published: January 2006

This article analyses notions of ‘transfer’ in the literature of comparative education, searching for continuities and discontinuities in the way that the process of educational transfer has been construed. The analysis shows that the theme of transfer has been fundamental in comparative education from the early nineteenth century until the present day. Although some of the questions addressed in the field since its origins are still crucial today, it is suggested in the final part of the study that these problems should now be addressed in a world in which educational space has become more complex, as supra-national and sub-national actors become increasingly important in the production and reproduction of specialised knowledge about education.
Virtual Networks, Support Stockings and Community. Online Publication: A New Context of Meaning for Comparative and International Education?
Authors: O'Dowd Mina
Published: January 2006

This article addresses the advent of this online only publication, the very context in which it is being made available. Central to the article is Delanty's work on communicative communities. It is argued that it is particularly appropriate to view comparative and international education in this manner. Online publication offers comparative and international education a new context of meaning. Seen in this context, comparative and international education can be reformulated as one of the communicative communities that are more about communication than place, more about belonging than boundaries, more about the production of meaning than about the reproduction of meaning.

If we are to achieve a richer culture, rich in contrasting values, we must recognize the whole gamut of potentialities, and so weave a less arbitrary social fabric, one in which diverse human gifts will all find a fitting place. (Margaret Mead, 1935)

The world is not an unsolved puzzle waiting for the occasional genius to unlock its secrets. The world, or most of it, is an empty space waiting to be filled. Life, work and organization could become a self-fulfilling prophecy. (Charles Handy, 1996)[1]
Polyamides, Plastics
Authors: Palmer Robert J. ,   Updated by Staff
Published: January 2006

Polyamides (nylons) are important engineering plastics as well as being well known for fiber applications. This article covers the properties, manufacture, processing, and use of polyamide plastics together with information on specifications, sales, and suppliers. Materials discussed include nylon‐6,6, nylon‐6, nylon‐6,9, nylon‐6,12, nylon‐11, nylon‐12, nylon‐4,6, amorphous nylon, and other semiaromatic nylons. Physical properties described are crystallinity, thermal properties, moisture absorption, electrical properties, and flammability. Chemical properties are hydrolysis/polycondensation, thermal degradation, oxidation, uv aging, and effect of chemicals and solvents. Manufacture is described including solid‐state polymerization, compounding, and pultrusion. Compounding also includes a review of additives and modifications covering lubricants, nucleants, stabilizers, impact modifiers, flame retardants, plasticizers, reinforcements, nanocomposites, and polymer blends. The following processing routes are detailed: injection molding, extrusion, film, tubing and pipe, monofilament, rods and profiles, wire and cable coating, blow molding, rotomolding, reaction injection molding, powder coating, and also assembly techniques. Economics and recycling issues are discussed. Specifications, standards, and quality control are also reviewed with an indication of appropriate test methods.
Thermal and structural characterization of quasi‐nanometer zirconium carbon/polyurethane composites prepared under roller pressure
Authors: Suen Maw‐Cherng , Chen Cheng‐Chi
Published: January 2006

In this study, we use quasi‐nanometer zirconium carbon (ZrC) to compose with polyurethane (PU) resin under roller pressure to study the interaction between the ZrC particle and PU molecules in the composite films, and find that the values of tensile strength, modulus, energy at break, Tm of soft‐segment, and Tg of soft‐segment, and weight percentage of char yield are increased, and elongation and char yield temperature are decreased with the increase of ZrC composed in PU, as this composed amounts are lower than 2.5%. The infrared spectroscopic spectra and wide angle X‐ray diffraction patterns reveal that the ether and ester groups of PU polymer can interact with ZrC to lower the interlayer distance of the crystal of PU polymer in composites. We assure that the interaction between the particles of ZrC and PU under roller pressure is in preparation process and account that the interaction between the particle and PU molecule will be an important factor to evaluate whether the particle in the composite is even and perfect. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 191–197, 2006
Electrodialytic transport properties of heterogeneous cation‐exchange membranes prepared by gelation and solvent evaporation methods
Authors: Kariduraganavar M. Y. , Nagarale R. K. , Kulkarni S. S.
Published: January 2006

The heterogeneous cation‐exchange membranes were prepared by employing two different methods: immersing the cation‐exchange resin‐loaded membranes in gelation bath; evaporating the solvent upon casting a uniform solution of cation‐exchange resin on a glass plate. The effect of resin loading on the electrochemical properties of the membranes was evaluated. The permselectivity of these heterogeneous membranes and transport number of calcium ions relative to sodium ions was evaluated with respect to the extent of resin loading and the methods of preparation. It is found that the membrane potential, transport number, permselectivity, and relative transport number are prominently high in the solvent evaporation method compared with the gelation method. The transport number of calcium ions relative to sodium ions in the solvent evaporation method increased monotonously with increasing resin loading. However, the increase of resin loading did not influence much on the relative transport numbers in the gelation method. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 198–207, 2006
Influence of pretreatment on shear strength of various wood species
Authors: Uysal Burhanettin
Published: January 2006

A study was conducted to determine the effects of wood pretreatment on the bonding strength of wood materials. The woods used for the test samples (based on BS EN 204) were oriental beech (Fagus orientalis Lipsky), Scotch pine (Pinus sylvestris L.), oak (Quercus petreae Liebl.), and chestnut (Castanea sativa Mill.). They were impregnated with Tanalith‐C, creosote, and Protim 230 WR–paraffin by full‐cell methods according to ASTM D 1413‐76 standards and the directions of the manufacturers. After impregnation, shear strength tests (based on BS EN 205) were applied on the samples bonded with poly(vinyl acetate) (PVAc), Desmodur‐VTKA, and Pattex fast. The highest shear strength was obtained in nonimpregnated (control) and PVAc‐D1 glued oak (5.328 N/mm2), and the lowest shear strength was obtained in Protim 230 WR–paraffin and Pattex fast glued chestnut (0.169 N/mm2). Accordingly, the impregnation process negatively affected the adhesive bonding strength. Impregnation chemicals, especially containing oily or similar substances, could not be proposed for wood elements exposed to shear strength. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 245–252, 2006
Analysis of the structural characteristics of nanoscale silk particles
Authors: Li Y. , Yuen C. W. M. , Hu J. Y. , Cheng Y. F.
Published: January 2006

Nanoscale silk particles were prepared from silk fibers by a special pretreatment with the aid of specially designed machinery and techniques. Scanning electron micrographs showed that the particle sizes of the silk powders produced from silk fibers around 9–11 μm in diameter decreased from a microscale to a nanoscale after three stages of pulverization, and this was further confirmed with a laser particle size analyzer. Fourier transmission infrared analysis showed that there were no substantial changes in the chemical structure of the silk after the pulverization processes. The silk powders after the second and third pulverizations slightly differed from that of the silk fiber and the particles after the first pulverization with a greater amount of the primary aliphatic amines. Also, there were secondary amides present in the silk fiber and the powders after the first and second pulverizations but absent in the powders after the third pulverization. Moreover, the silk powders after the third pulverization had a greater number of C(CH3)3 groups than the silk fibers and the powders after the first and second pulverizations. X‐ray diffraction analysis showed that the crystallinity of the silk powders decreased when the particle sizes decreased, particularly to nanoscales. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 268–274, 2006
Synthesis and photoinitiation properties of a novel quaternary ammonium tetraphenylborate salt
Authors: Yu Xueya , Chen Jia , Yang Jianwen , Zeng Zhaohua , Chen Yonglie
Published: January 2006

Quaternary ammonium salts are photobase generators. Recently, we prepared a novel quaternary ammonium tetraphenylborate salt bearing a 6‐methoxynaphthoylmethyl group. The structure of the products was confirmed by elemental analysis and 1H‐NMR. Thermogravimetry showed its good thermostability. UV spectra and fluorescence emission spectra of the samples were studied. A mass spectrometry method for the analysis of the tertiary amine and other fragments produced by photolysis was established. Photolysis was found to produce both tertiary amine and free radicals. Therefore, the products of photolysis not only could cause thermal curing of epoxide but also could initiate the free‐radical polymerization of acrylate or methyl acrylate monomer. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 399–405, 2006
Structured radiation‐grafted polymer films and membranes
Authors: Rager Timo
Published: January 2006

The patterning of radiation‐grafted polymer films and membranes on a 1‐mm scale was investigated as a means of improving the mechanical properties of these materials. Stress–strain measurements indicated that no positive effect was achieved. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 292–294, 2006
Blue‐light‐emitting poly(arylene ethynylenes) containing alternating sequences of biphenylene or fluorenediyl and p‐phenylene moieties linked through triple bonds
Authors: Joo Sung‐Hoon , Jeong Mi‐Yun , Ko Doo Hyun , Park Jong‐Hyun , Kim Ki Yong , Bae Sung Joon , Chung In Jae , Jin Jung‐Il
Published: January 2006

Two new poly(arylene ethynylenes) were synthesized by the reaction of 1,4‐diethynyl‐2.5‐dioctylbenzene either with 4,4′‐diiodo‐3,3′‐dimethyl‐1,1′‐biphenyl or 2,7‐diiodo‐9,9‐dioctylfluorene via the Sonogashira reaction, and their photoluminescence (PL) and electroluminescence (EL) properties were studied. The new poly(arylene ethynylenes) were poly[(3,3′‐dimethyl‐1,1′‐biphenyl‐4,4′‐diyl)‐1,2‐ethynediyl‐(2,5‐dioctyl‐1,4‐phenylene)‐1,2‐ethynediyl] (PPEBE) and poly[(9,9‐dioctylfluorene‐2,7‐diyl)‐1,2‐ethynediyl‐(2,5‐dioctyl‐1,4‐phenylene)‐1,2‐ethynediyl] (PPEFE), both of which were blue‐light emitters. PPEBE not only emitted better blue light than PPEFE, but it also performed better in EL than the latter when the light‐emitting diode devices were constructed with the configuration indium–tin oxide/poly(3,4‐ethylenedioxythiophene) doped with poly(styrenesulfonic acid) (50 nm)/polymer (80 nm)/Ca:Al. The device constructed with PPEBE exhibited an external quantum efficiency of 0.29 cd/A and a maximum brightness of about 560 cd/m2, with its EL spectrum showing emitting light maxima at λ = 445 and 472 nm. The device with PPEFE exhibited an efficiency of 0.10 cd/A and a maximum brightness of about 270 cd/m2, with its EL spectrum showing an emitting light maximum at λ = 473 nm. Hole mobility (μh) and electron mobility (μe) of the polymers were determined by the time‐of‐flight method. Both polymers showed faster μh values. PPEBE revealed a μh of 2.0 × 10−4 cm2/V·s at an electric field of 1.9 × 105 V/cm and a μe of 7.0 × 10−5 cm2/V·s at an electric field of 1.9 × 105 V/cm. In contrast, the mobilities of the both carriers were slower for PPEFE, and its μh (8.0 × 10−6 cm2/V·s at an electric field of 1.7 × 106 V/cm) was 120 times its μe (6.5 × 10−8 cm2/V·s at an electric field of 8.6 × 105 V/cm). The much better balance in the carriers' mobilities appeared to be the major reason for the better device performance of PPEBE than PPEFE. Their highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels were also a little different from each other. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 299–306, 2006
Interpenetrating polymer networks of poly(butyl methacrylate) and poly(α‐terpineol‐co‐styrene): Synthesis and characterization
Authors: Pathak Shalini , Srivastava A. K.
Published: January 2006

Simultaneous interpenetrating polymer networks (IPNs) based on poly(butyl methacrylate) and poly(α‐terpineol‐co‐styrene) were synthesized with azobisisobutyronitrile (AIBN) as the initiator and divinyl benzene as the crosslinking agent in xylene under an inert nitrogen atmosphere. Fourier transform infrared spectra provided structural evidence for the IPNs, indicating characteristic frequencies of ester groups of butyl methacrylate at 1723 cm−1 and alcoholic groups of α‐terpineol at 3436 cm−1. Scanning electron microscopy revealed threadlike network structures. Properties such as percentage swelling and average molecular weight between crosslinks were direct functions of the copolymer and initiator (AIBN) concentrations and inverse functions of the monomer (butyl methacrylate) and crosslinking agent (divinyl benzene) concentrations. Differential scanning calorimetry showed an IPN glass‐transition temperature at 80.2°C. The thermal decompositions of the IPNs were established with the help of thermogravimetric analysis. The value of the activation energy, calculated from thermogravimetric analysis with the Coats and Redfern equation, was 23 kJ/mol. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 343–352, 2006
Characterization and photoluminescence properties of diglycidyl methacrylic resin doped with the Eu3+–β‐diketonate complex
Authors: Parra D. F. , Mucciolo A. , Duarte D. G. , Brito H. F. , Lugão A. B.
Published: January 2006

Triaquatris(acetyl acetonate)europium(III) [Eu(acac)3] at 1, 5, 10, and 15% was doped in diglycidyl methacrylic (DGMA) resin, and their luminescent properties in the solid state are reported. These systems were characterized with elemental analysis, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy. On the basis of TGA data, the thermal stability of the DGMA/Eu(acac)3x% system was similar to that of the polymer, except at the highest concentration (15%). The DSC results indicated that the new systems were chemically stable and underwent the cure process before decomposition. The emission spectra of the Eu3+/acetyl acetonate complex doped in DGMA, recorded at 298 and 77 K, exhibited the characteristic bands arising from the 5D0→7FJ transitions (J = 0–4). The luminescence intensity decreased with an increasing precursor concentration in the doped polymer. The system doped at a low concentration (1% Eu3+ complex) presented more luminescence efficiency than those doped at 5, 10, and 15%. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 406–412, 2006
Natural rubber/poly(ethylene‐co‐vinyl acetate)‐blend‐based nanocomposites
Authors: Sharif Jamaliah , Yunus Wan Md Zin Wan , Dahlan Khairulzaman Hj , Ahmad Mansor Hj
Published: January 2006

Natural rubber (NR)/poly(ethylene‐co‐vinyl acetate) (EVA) blend–clay nanocomposites were prepared and characterized. The blend nanocomposites were prepared through the melt mixing of NR/EVA in a ratio of 40/60 with various amounts of organoclay with an internal mixer followed by compression molding. X‐ray diffraction patterns revealed that the nanocomposites formed were intercalated. The formation of the intercalated nanocomposites was also indicated by transmission electron microscopy. Scanning electron microscopy, used to study the fractured surface morphology, showed that the distribution of the organoclay in the polymer matrix was homogeneous. The tensile modulus of the nanocomposites increased with an increase in the organoclay content. However, an increase in the organoclay content up to 5 phr did not affect the tensile strength, but the organoclay reduced this property when it was increased further. This study also indicated that a low silicate content dispersed in the blend matrix was capable of increasing the storage modulus of the material. The addition of the organoclay also increased the decomposition temperature of the NR/EVA blends. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 353–362, 2006
4‐chloro‐3‐methylphenyl methacrylate copolymers with 2,4‐dichlorophenyl methacrylate: Synthesis, characterization, and antimicrobial activity
Authors: Patel Jatin N. , Dolia Mitul B. , Patel Mitesh B. , Patel Rajni M.
Published: January 2006

4‐Chloro‐3‐methylphenyl methacrylate (CMPM) and 2,4‐dichlorophenyl methacrylate (2,4‐DMA) were synthesized by reacting methacryloyl chloride with 4‐chloro‐3‐methylphenol (CMP) and 2,4‐dichlorophenol (2,4‐DP), respectively. Homo and copolymers of CMPM and 2,4‐DMA were obtained from different monomer feed ratios, using 2,2′‐azobisisobutyronitrile as initiator in toluene at 70°C. IR‐spectroscopy was employed to characterize the resulting homo and copolymers. Copolymer compositions were determined by ultraviolet (UV) spectroscopy. Fineman–Ross method was used to calculate the reactivity ratios of the monomers. Average molecular weight and polydispersity index were obtained by gel permeation chromatography (GPC). Thermogravimetric analyses (TGA) and differential thermal analysis (DTA) of copolymers were carried out under a nitrogen atmosphere. Antimicrobial effects of the homo and copolymers were also investigated for various microorganisms such as bacteria, fungi, and yeast. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100:439–448, 2006
Modification of unsaturated polyester resin by polyurethane prepolymers
Authors: Cherian A. Benny , Abraham Beena T. , Thachil Eby Thomas
Published: January 2006

Unsaturated polyester resins (UPRs) are extensively used by the fiber‐reinforced plastic (FRPs) industry. These resins have the disadvantages of brittleness and poor resistance to crack propagation. In this study, UPRs were chemically modified by reactive blending with polyurethane prepolymers having terminal isocyanate groups. Hybrid networks were formed by copolymerisation of unsaturated polyesters with styrene and simultaneous reaction between terminal hydroxyl groups of unsaturated polyester and isocyanate groups of polyurethane prepolymer. The prepolymers were based on toluene diisocyanate (TDI) and each of hydroxy‐terminated natural rubber (HTNR), hydroxy‐terminated polybutadiene (HTPB), polyethylene glycol (PEG), and castor oil. Properties like tensile strength, toughness, impact resistance, and elongation‐at‐break of the modified UPRs show considerable improvement by this modification. The thermal stability of the copolymer is also marginally better. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 449–456, 2006
Epoxidized phenolic novolac: A novel modifier for unsaturated polyester resin
Authors: Cherian A. Benny , Thachil Eby Thomas
Published: January 2006

Unsaturated polyester resins (UPRs) are used widely in the fiber‐reinforced plastics (FRPs) industry. These resins have the disadvantages of brittleness and poor resistance to crack propagation. In this study, hybrid polymer networks (HPNs) based on UPR and epoxidized phenolic novolacs (EPNs) were prepared by reactive blending. A HPN is composed of a backbone polymer containing two types of reactive groups that can take part in crosslinking reactions via different mechanisms. EPNs were prepared by glycidylation of novolacs using epichlorohydrin. The novolacs had varying phenol: formaldehyde ratios. Blends of unsaturated polyester with EPN were then prepared. The physical properties of the cured blends were compared with those of the control resin. EPN shows good miscibility and compatibility with the resin and improves the toughness and impact resistance substantially. Considerable enhancement of tensile strength is also noticed at about 5% by weight of epoxidized novolac resin. TGA, DMA, and DSC were used to study the thermal properties of the toughened resin and the fracture behavior was studied using SEM. The blends are also found to have better thermal stability. Blending with EPN can be a useful and cost‐effective technique for modification of UPR. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 457–465, 2006
Preparation of high‐molecular‐weight poly(L‐lactic acid)‐based polymers through direct condensation polymerization in bulk state
Authors: Kim Hun Sik , Hwang Mi Ok , Kim Mal Nam , Yoon Jin San
Published: January 2006

Poly(L‐lactic acid‐co‐succinic acid‐co‐1,4‐butanediol) (PLASB) was synthesized by a direct condensation copolymerization of L‐lactic acid, succinic acid (SA), and 1,4‐butanediol (BD) in bulk state using titanium(IV) butoxide (TNBT) as a catalyst. Weight average molecular weight (Mw) of PLASB increased from 3.5 × 104 to 2.1 × 105 as the content of SA and BD went up from 0.01 to 0.5 mol/100 mol of L‐lactic acid (LA). PLASB having Mw in the range from 1.8 × 105 to 2.1 × 105 showed tensile properties comparable to those of commercially available poly(L‐lactic acid) (PLLA). In sharp contrast, homopolymerization of LA in bulk state produced PLLA with Mw as low as 4.1 × 104, and it was too brittle to prepare specimens for the tensile tests. Mw of PLASB synthesized by using titanium(IV)‐2‐ethyl(hexoxide), indium acetate, indium hydroxide, antimony acetate, antimony trioxide, dibutyl tin oxide, and stannous‐2‐ethyl 1‐hexanoate was compared with that of PLASB obtained by TNBT. Ethylene glycol oligomers with different chain length were added to LA/SA in place of BD to investigate effect of chain length of ethylene glycol oligomers on the Mw of the resulting copolymers. Biodegradability of PLASB was analyzed by using the modified Sturm test. Toxicity of PLASB was evaluated by counting viable cell number of mouse fibroblast cells that had been in contact with PLASB discs. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 466–472, 2006
Differential scanning calorimetry of urea–formaldehyde adhesive resins, synthesized under different pH conditions
Authors: Park Byung‐Dae , Kang Eun‐Chang , Park Jong Young
Published: January 2006

The purpose of this study was to investigate the effects of reaction pH conditions on thermal behavior of urea–formaldehyde (UF) resins, for the possible reduction of formaldehyde emission of particleboard bonded with them. Thermal curing properties of UF resins, synthesized at three different reaction pH conditions, such as alkaline (pH 7.5), weak acid (pH 4.5), and strong acid (pH 1.0), were characterized with multiheating rate method of differential scanning calorimetry. As heating rate increased, the onset and peak temperatures increased for all three UF resins. By contrast, the heat of reaction (ΔH) was not much changed with increasing heating rates. The activation energy (Ea) increased as the reaction pH decreased from alkaline to strong acid condition. The formaldehyde emission of particleboard was the lowest for the UF resins prepared under strong acid, whereas it showed the poorest bond strength. These results indicated that thermal curing behavior was related to chemical species, affecting the formaldehyde emission, while the poor bond strength was believed to be related to the molecular mobility of the resin used. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 422–427, 2006
A conducting nanocomposite of acetylene black with preformed poly‐N‐vinylcarbazole crosslinked by anhydrous FeCl3
Authors: Maity Arjun , Biswas Mukul
Published: January 2006

A conducting nanocomposite of crosslinked poly‐N‐vinylcarbazole (CLPNVC) with nanodimensional acetylene black (AB) was prepared by oxidative crosslinking of preformed PNVC through pendant carbazole moieties in presence of anhydrous FeCl3 as an oxidant and AB suspension in CHCl3 medium at 65°C. The incorporation of CLPNVC moieties in the CLPNVC‐AB composite was endorsed by Fourier transform infrared analysis. Scanning electron microscopic analysis showed formation of lumpy aggregates with average sizes in the 130–330 nm ranges. The thermal stability of the CLPNVC‐AB composite was appreciably higher than that of the PNVC‐AB composite. The direct current conductivities of the composites were significantly enhanced relative to that of the PNVC homopolymer (10−12–10−16 S/cm) and varied in the range of 10−4–10−2 S/cm depending on the amount of AB loading in the CLPNVC‐AB composite. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 819–824, 2006
Thermal and mechanical behavior of unsaturated polyesters filled with phase change material
Authors: Çaylı Gökhan , Küsefoğlu Selim
Published: January 2006

Samples of commercial unsaturated polyester (UPE) resin, filled with phase‐changeable fillers (PCMs), were prepared, and the thermal and mechanical properties of the cured samples were examined. Fillers chosen were paraffin and Wood's metal. Samples were prepared by making dispersions of these fillers in liquid unsaturated polyester followed by curing with methyl ethyl ketone peroxide (MEKP) and conaphtanate and rigid thermoset samples filled with PCM particles were obtained. The thermal and mechanical behaviors of such a filled composite around the melting points of fillers are very interesting. Effects of varying proportions of PCM on mechanical and thermal properties of final products were examined. The samples show thermal melting behavior without undergoing a change in physical state. Decreases in the maximum working temperature from 75 to 53°C for metal‐filled samples and from 75 to 43°C for paraffin‐filled samples were observed by using dynamic mechanical thermal analysis. Differential scanning calorimetry indicated that heat absorption of paraffin samples were higher than that of metal‐filled samples. For paraffin‐filled samples, heats of fusion were 3.44 cal/g for 10% filled sample and 6.35 cal/g for 20% filled sample. For Wood's metal‐filled samples, heats of fusion were 1.18 cal/g for 10% metal‐filled sample and 1.54 cal/g for 20% metal‐filled sample. Surface hardness was tested with Shormeter D. Surface hardness of metal‐filled composites varied from 86 to 34 shore D at 21°C and 80.6 to 35 shore D at 80°C. For paraffin‐filled samples, surface hardness changed from 86 to 42 shore D at 21°C and from 80.6 to 13 shore D. Morphology of the samples was determined by scanning electron microscopy, of the crack surfaces. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 832–838, 2006
Studies on chemically modified hen egg white and gelatin composites
Authors: Venkateswarlu U. , Boopalan Kamala , Mohan R. , Das B. N. , Sastry T. P.
Published: January 2006

Hen egg white (A) and gelatin (G) composites at different proportions were prepared and optimized by their stress–strain behavior. The optimized composite (AG) was graft copolymerised with methyl methacrylate (MMA). The AG and its graft copolymer AGMMA were characterized for their mechanical strength, water absorption capacity, Fourier transform infrared spectra, and circular dichroism (CD) spectroscopy. It was evident from the results that AGMMA possesses higher mechanical strength and lower water absorption capacity than does AG. The FTIR spectra of AG and AGMMA confirm the grafting phenomena of MMA onto AG, and the CD spectrum of AG shows two negative bands at around 207 and 222 nm and a positive band at around 191.76 nm, which confirms the α‐helix in the composite. The α‐helical structure in AG was broken and converted into unordered random coil in AGMMA because of the reaction conditions while grafting MMA onto AG, which was confirmed by the increase in mechanical strength of AGMMA. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 318–322, 2006
Structure and properties of polyimide‐bonded magnets processed from prepolymers based on diacetyl derivatives of aromatic diamines and dianhydrides
Authors: Yudin V. E. , Otaigbe J. U. , Bui Tho X. , Svetlichnyi V. M.
Published: January 2006

We report a novel method of polyimide (PI) synthesis from prepolymers based on dianhydrides and diacetyl derivatives of aromatic diamines that facilitate the preparation of a melt processable mixture at 300 ± 10°C of the prepolymer and magnetic Nd‐Fe‐B alloy to provide PI‐bonded magnets with enhanced properties. It is shown that chemical structure of the prepolymers strongly influences viscosity behavior via crystallization of the oligoimide in the melt, leading to formation of PI with rigid‐rod like structure. This structural ordering of the prepolymers based on diacetyl derivative of diamine used in this study, if not controlled, leads to exponential increase of melt viscosity with time, making it practically impossible to prepare melt processable mixture of the magnetic particles and the PI prepolymers at elevated temperatures. The results obtained demonstrate that appropriate dianhydrides and diacetyl derivatives of diamines that do not lead to crystallization of oligoimides in prepolymer mixture can be used under controlled processing conditions to prepare melt‐processable PI‐bonded magnets containing rigid‐rod like PI structure that significantly increases thermal stability of the magnets. The temperature dependencies of the magnetic properties of the PI‐bonded magnets under conditions that they are likely to encounter during their service life were found to be remarkably similar to that of commercial thermoplastic magnets such as injection‐molded nylon magnets. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 478–485, 2006
Effect of coexcipients on drug release and floating property of nifedipine hollow microspheres: A novel gastro retentive drug delivery system
Authors: Soppimath Kumaresh S. , Aminabhavi Tejraj M. , Agnihotri Sunil A. , Mallikarjuna Nadagouda N. , Kulkarni Padmakar V.
Published: January 2006

A gastro retentive drug‐delivery system for nifedipine was developed by incorporating the drug in cellulose acetate hollow microspheres capable of floating on the gastric and intestinal fluid. The microspheres were prepared by solvent diffusion–evaporation technique in the presence of coexcipients like polyethylene glycol, dibutyl phthalate, and poly(ε‐caprolactone) using ethyl acetate as a dispersing solvent. Size of the microparticles depends upon the type and concentration of the excipient used. Microparticles exhibited floating properties on the simulated‐gastric fluid for >12 h. Their percentage buoyancy followed the rank order of: blank (no coexcipients) > dibutyl phthalate > polyethylene glycol > poly(ε‐caprolactone) after 15 h of floating. Release of nifedepine was enhanced by the addition of coexcipients. The drug release followed non‐Fickian transport in almost all formulations. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 486–494, 2006
Effect of hydrotalcite on the swelling and mechanical behaviors for the hybrid nanocomposite hydrogels based on gelatin and hydrotalcite
Authors: Lee Wen‐Fu , Lee Sung‐Chuan
Published: January 2006

A series of hybrid nanocomposite hydrogels, based on gelatin and intercalated hydrotalcite (IHT), crosslinked with glutaraldehyde, was prepared in this study. The microstructures of the IHT and sample gels were identified by X‐ray diffraction (XRD). Swelling behaviors and physical properties of these hybrid gels were investigated. XRD results indicated that exfoliation of IHT was achieved in the hybrid nanocomposite gels. The results indicated that adding a small amount of IHT could effectively decrease the swelling ratio of the hybrid gels, but adding excess IHT could increase the swelling ratio of the nanocomposite hybrid gels. The crosslinking densities (ρx) of the present gels varied with IHT content and swelling ratio of the gels. The drug release behaviors of these gels were also investigated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 500–507, 2006
High temperature bulk copolymerization of methyl methacrylate and acrylonitrile. I. Reactivity ratio estimation
Authors: Khesareh R. , McManus N. T. , Penlidis A.
Published: January 2006

The copolymerization of methyl methacrylate and acrylonitrile has been studied in the bulk phase. Experiments for estimating reactivity ratios were conducted at 60, 100, 120, and 140°C. Tidwell–Mortimer and the feed composition constraint approaches were used to design the experiments. The error in variables model (EVM) method was employed to evaluate the reactivity ratios and analyze the error involved. The results show that the reactivity ratios do not vary significantly with temperature up to 140°C. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 843–851, 2006
Shear creep resistance of styrene–isoprene–styrene (SIS)‐based hot‐melt pressure‐sensitive adhesives
Authors: Kim Dae‐Jun , Kim Hyun‐Joong , Yoon Goan‐Hee
Published: January 2006

The effects of the properties of substrates and tackifier on the shear creep of SIS‐based HMPSAs were investigated. The holding power (tb) and shear adhesion failure temperature (SAFT) were measured. The relationship between the complex viscosity and the holding power was examined. The holding power and SAFT values of the triblock SIS blends were higher than those of the diblock‐containing SIS blends, perhaps because blends using triblock SIS have higher crossover temperature and complex viscosity than those using diblock‐containing SIS. Higher levels of aromatic resin‐modified aliphatic tackifier and rosin ester were found to decrease the holding power of the HMPSAs. This maybe due to the fact that rosin ester and aromatic‐modified aliphatic resin are compatible with both the ends and midblocks of SIS. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 825–831, 2006
Synthesis and characterization of novel polyureas based on benzimidazoline‐2‐one and benzimidazoline‐2‐thione hard segments
Authors: Raghu A. V. , Gadaginamath G. S. , Mallikarjuna N. N. , Aminabhavi T. M.
Published: January 2006

Six novel polyureas were prepared from benzimidazolin‐2‐one and benzimidazolin‐2‐thione, which acted as hard segments, with two aromatic diisocyanates (4,4′‐diphenylmethane diisocyanate and toluene 2,4‐diisocyanate) and one aliphatic diisocyanate (hexamethylene diisocyanate). The polymers that formed were fully characterized with Fourier transform infrared spectroscopy, 13C‐NMR cross‐polarization/magic‐angle spinning, differential scanning calorimetry, and thermogravimetry. X‐ray diffraction revealed that the polymers contained crystalline and amorphous regions that varied with the nature of the backbone structures. All the polyureas were insoluble in common organic solvents, and this made it difficult to investigate their solution properties. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 576–583, 2006
Effect of temperature and type of food simulant on antioxidant stability
Authors: Dopico‐García M.S. , López‐Vilariño J.M. , González‐Rodríguez M.V.
Published: January 2006

Additive migration levels in food simulants from polimeric materials that are intended to be into contact with food can be affected by additive stability under the migration test conditions. In this work, the stability of some phenolic antioxidants and one oxidized phosphite antioxidant was studied in four food simulants: distilled water, 3% (w/v) acetic acid, 10% (v/v) ethanol, and the fatty food simulant olive oil, under different temperatures 5, 40, and 70°C, during ∼20 days. Samples were analyzed by reversed‐phase high performance liquid chromatography (HPLC) with UV diode‐array detector. In general, antioxidants appeared to be more stable in olive oil than in the aqueous simulants. Among aqueous simulants, water and 10% ethanol allowed the highest stability of antioxidants at low temperatures. The 3% acetic acid allowed good stability for the lowest phenolic compounds even at high temperatures, but the highest molecular weight compounds decomposed very fast even at low temperatures. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 656–663, 2006
Fracture toughness in random‐chopped fiber‐reinforced composites and their strain rate dependence
Authors: Jacob George C. , Starbuck James Michael , Fellers John F. , Simunovic Srdan , Boeman Raymond G.
Published: January 2006

While many scientists have investigated the fracture toughness properties in various continuous fiber‐reinforced composite materials and their dependence on strain rate, there is absolutely no literature available on the fracture toughness properties of random‐chopped fiber‐reinforced composite materials and their strain rate dependence, which can find extensive use in a wide range of load‐bearing engineering and industrial process applications primarily due to the low costs involved in their manufacture in addition to the ease of manufacture. Therefore, the primary goal of this manuscript is to determine the fracture toughness of various random‐chopped carbon fiber composite material systems. The four different random‐chopped carbon‐reinforced epoxy composite material systems studied were P4, HexMC, CCS150, and CCS100. In addition, an attempt is made to investigate and characterize the strain rate effects on the fracture toughness of a random‐chopped carbon fiber P4 composite. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 695–701, 2006
Differential scanning calorimetric and free volume study of reactive compatibilization by EPM‐g‐MA of poly(trimethylene terephthalate)/EPDM blends
Authors: Ravikumar H. B. , Ranganathaiah C. , Kumaraswamy G. N. , Deepa Urs M. V. , Jagannath J. H , Bawa A. S. , Thomas Sabu
Published: January 2006

Differential scanning calorimetry (DSC) and positron annihilation lifetime measurements have been carried out to study the effect of the compatibilizer maleic anhydride grafted ethylene propylene copolymer (EPM‐g‐MA) in poly trimethylene terephthalate and ethylene propylene diene monomer (PTT/EPDM) immiscible blends. The DSC results for the blends of 50/50 and 30/70 compositions show two clear glass transition temperatures, indicating that the blends are two‐phase systems. With the addition of compatibilizer, the separation between the two glass transitions decreased, suggesting an increased interaction between the blend components with compatibilizer. At 5 wt % of compatibilizer, the separation between the Tgs reduced in both 50/50 and 30/70 blends. The positron results for the blends without compatibilizer showed an increase in relative fractional free volume, as the EPDM content in the blend is increased. This suggests the coalescence of free volume of EPDM with the free volumes of PTT due to phase separation. However, the effect of compatibilizer in the blends was clearly seen with the observed minimum in free volume parameters at 5% of the compatibilizer, further suggesting that this percent of compatibilizer seems to be the optimum value for these blends. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 740–747, 2006