bluuebunny/crossref_metadata_2025 huggingface dataset:
Winter Roosting Ecology of Eastern Red Bats in Southwest Missouri
Authors: MORMANN BRAD M. , ROBBINS LYNN W.
Published: March 2007

Abstract:Eastern red bats (Lasiurus borealis) have been found to overwinter in areas that can experience severe fluctuations in temperature. We examined the red bat's use of winter roosts in southwest Missouri, USA, for 2 winters (2003–2005). We found tree roosts in eastern red cedars (Juniperus virginiana) and hardwoods. Tree roost sites were located on the south side of trees, and we found roost trees on south‐facing slopes. Roost sites occurred more frequently in the location with least canopy cover. Bats switched from tree roosts to leaf litter roosts when ambient temperatures approached or fell below freezing. We found habitat characteristics and aspect to be determining factors in the selection of leaflitter roosts. Management of overwintering red bats requires a diverse forest structure, including canopy gaps, stand‐density variation, and leaf‐bearing trees, including oaks (Quercusspp.).
Effects of Fertility Control on Behavior and Disease Transmission in Brushtail Possums
Authors: RAMSEY DAVE
Published: March 2007

Abstract:Fertility control is currently under development for the control of brushtail possums (Trichosurus vulpecula), one of New Zealand's most serious vertebrate pests. Despite intensive research into various methods for achieving infertility, including immunocon‐traception and disrupting endocrine control of reproduction, researchers know little about the potential effects of these methods on the behavior of wild possums. We assessed the effects of surgically imposed sterility, either to block fertilization (tubal ligation) or to disrupt endocrine control of fertility (gonadectomy), by using radiotelemetry on the movement patterns and site fidelity of wild brushtail possums. In addition, we assessed the effect of gonadectomy on the transmission rate of a commonly occurring, directly transmitted pathogen in possums,Leptospira interrogansserovarbalcanica(hereafterL. balcanica), to determine the effect of any behavioral changes on possum contact rates. Both tubal ligation and gonadectomy of females did not appear to have any appreciable effect on behavior, with sterilized females having space‐use patterns and fidelity to seasonal breeding ranges similar to those of fertile females. However, gonadectomy of male possums resulted in a significant reduction of 42% and 47% in the 95% and 70% isopleth seasonal breeding ranges, respectively. Furthermore, the transmission rate ofL. balcanicain gonadectomized male and female possums was reduced by 88% and 63%, respectively, compared with that in fertile male and female possums. Overall, these results suggest that fertility control, either by blocking fertilization (e.g., immunocontraception) or by disrupting endocrine control of reproduction (e.g., gonadotropin‐releasing hormone vaccines), is unlikely to have an impact on social organization and behavior of brushtail possums in ways that may compromise the efficacy of fertility control for reducing population density. However, the reduction in the transmission rate ofL. balcanicaindicates that fertility control that interferes with endocrine control of reproduction is likely to reduce the contact rate between possums. This could have implications for the control of other wildlife diseases requiring direct contact for transmission.
Integrating Professional Skills in Wildlife Student Education
Authors: KROLL A J.
Published: March 2007

Abstract: Recent articles have called for enhanced quantitative proficiency in wildlife students, arguing that such training will increase scientific rigor and produce wildlife researchers and managers who are better able to remedy current problems and to address future challenges in wildlife management. The idea that better, or more rigorous, science is the panacea for controversial natural resource problems is a cavalier and common presumption in many applied professions and one to which wildlife science and management is not immune. However, science and management are distinct processes and although scientific rigor is important, dialogue between the 2 processes is more critical for successful interaction. Integrated training that exposes students to nontraditional coursework and develops essential professional skills, such as planning, consensus‐building, and communication, can help produce graduates to bridge the science—management gap and promote the conservation of natural resources. Changes in the structure and coursework of university wildlife departments can help to develop more effective wildlife professionals.
Survival of Rio Grande Wild Turkeys on the Edwards Plateau of Texas
Authors: COLLIER BRET A. , JONES DUSTIN A. , SCHAAP JODY N. , RANDEL CHARLES J. , WILLSEY BEAU J. , AGUIRRE RAY , SCHWERTNER T. WAYNE , SILVY NOVA J. , PETERSON MARKUS J.
Published: March 2007

Abstract: The southeastern portion of the Edwards Plateau of Texas, historically a stronghold of Rio Grande wild turkeys (Meleagris gallopavo intermedia), has seen a decline in turkey numbers since the 1970s. Because adult and juvenile survival are key parameters affecting turkey population dynamics, we used radiotagged individuals to compare Rio Grande wild turkey survival in areas of suspected decline versus stable portions of the Edwards Plateau during 2001–2003. Reproductive period (breeding or nonbreeding) had an impact on survival, but differences in age, sex, or region did not influence survival. Model averaged estimates of monthly survival were 0.97 (SE = 0.005) for nonbreeding periods and 0.96 (SE = 0.007) for breeding periods. Our results indicate juvenile and adult survival in the declining areas was similar to survival in the stable areas of the Edwards Plateau. This suggests causes of the decline might be associated with differences during other life‐history stages, such as nest success or poult survival, although we cannot rule out the possibility juvenile or adult survival contributed to the decline in the past. This situation demonstrates why wildlife managers should be cognizant of the implications of initiating long‐term monitoring programs after changes in population status occur, rather than initiating them in expectation of such changes.
Effect of Tooth Removal on Recaptures of Raccoons
Authors: BEASLEY JAMES C. , RHODES OLIN E.
Published: March 2007

Abstract:Researchers have extensively used mark—recapture techniques to obtain information on demographic parameters of wildlife populations. However, researchers have recognized that a number of factors can influence capture probabilities of wildlife species, which in turn can bias mark—recapture estimates of demographic parameters. Tooth extraction, which is a commonly used technique in studies of mesopredator species to obtain precise age estimates and to monitor the use of vaccine baits, is an aspect of animal handling that clearly might affect the recapture probability of individuals. However, the effect that tooth removal has on the individual recapture probabilities of wildlife species is unknown. During 2005, we trapped and marked 91 raccoons (Procyon lotor) in northern Indiana, USA, as part of a mark—recapture study designed specifically to determine if tooth extractions have an effect on recapture probabilities of individuals. We performed tooth extractions on 50% of the raccoons at the time of capture, and we attempted to balance tooth extractions with respect to sex and age of raccoons. We used logistic regression to model the effects of sex, age, and tooth removal on recapture probabilities, and we used Mann—WhitneyU‐tests to examine the effect of tooth removal on the number of times we recaptured individuals. The probability of recapture differed between sexes but did not differ as a function of tooth removal or among age classes. In addition, we failed to detect any difference in the mean number of times that we recaptured raccoons between the tooth removed and non—tooth‐removed groups. Our results suggest that managers can use tooth extractions as an effective management tool without biasing population estimates or compromising other management objectives.
A Frightening Device for Deterring Deer Use of Cattle Feeders
Authors: SEWARD NATHAN W. , PHILLIPS GREGORY E. , DUQUETTE JARED F. , VERCAUTEREN KURT C.
Published: March 2007

Abstract: The presence of bovine tuberculosis (TB) in cattle can negatively impact a state's economy and cattle industry. In Michigan, USA, wild white‐tailed deer (Odocoileus virginianus) are a reservoir for reinfecting cattle herds. Although direct TB transmission between deer and cattle is rare, infected deer may contaminate cattle feed. To mitigate this risk, we designed and evaluated a deer‐resistant cattle feeder (DRCF) device for deterring deer from feeders. The device delivered negative stimuli to condition deer to avoid cattle feeders. We tested the device by conducting a comparative change experiment at a high‐density captive white‐tailed deer operation in northeastern lower Michigan using pretreatment and treatment periods and random allocation of DRCF protection to 3 of 6 feeders during the treatment period. We used animal‐activated cameras to collect data on deer use of feeders. Deer use was similar at protected and unprotected feeders during the pretreatment period but was lower at protected feeders during the treatment period. Deer‐resistant cattle feeders were 100% effective during the first 2 treatment weeks, 94% during the first 5 weeks, but effectiveness then dropped to 61% during the final week. Excluding problems associated with low battery power and infrared sensors, DRCFs were 99% effective at deterring deer. Our results suggest that DRCFs can effectively limit deer use of cattle feed, potentially with minimal impact on feeding behavior of cattle, thus reducing potential transmission of bovine TB through contaminated feed. By employing DRCFs in bovine TB endemic areas, especially at times that deer are food stressed, agencies and producers can practically and economically reduce the potential for bovine TB to be transmitted from deer to cattle.
Synaptic Transmission: Intercellular Signaling
Authors: Jentsch J. David , Roth Robert H.
Published: March 2007

Within the central nervous system, inter‐neuronal signaling largely involves the activity‐dependent secretion of neural signaling molecules which produce electrophysiological, biochemical or transcriptional changes in target cells. In many, but not all, cases, these chemical messengers are released and have their effects within synapses, which are anatomically specialized appositions between neurons. Synaptic signaling involves the complex biochemical mechanisms involved the synthesis, sequestration, release and inactivation of the chemical signal by the releasing neuron and the response to that signal through its effects on a receptor protein expressed by the target neuron. In this chapter, we identify a set of chemical signaling molecules that have been identified as synaptic messengers, and we describe the mechanisms underlying their genesis, use and disposition. Critical points for modulation of these processes are discussed. In addition, recently discovered molecules that participate in inter‐cellular signaling but which defy conventional rules governing synaptic transmission are described.
Parkinson's Disease: Genetics and Pathogenesis
Authors: Testa Claudia M.
Published: March 2007

Current treatment for Parkinson's disease (PD) is entirely symptomatic. The extremely effective therapies aimed at the nigrostriatal dopaminergic system and motor symptoms fail to address non‐motor symptoms and their underlying neurobiology. Even with a renewed focus on non‐motor symptoms, PD therapeutics still lacks the ultimate therapy: a curative or neuroprotective agent. Such compounds will come out of a nuanced understanding of the pathophysiologic mechanisms of disease. New, rapid advances in medical genetics, neuroepidemiology, and neuroscience are driving interlocking theories of PD pathogenesis that may ultimately change the definition of disease to reflect biologic pathways in addition to clinical features. The list of PD‐related (PARK) loci and associated genes will change as PARK loci syndromes move away from PD definitions by clinical signs, neuropathology, or potential cause, or new syndromes fit into PD disease pathways. The current PARK loci, including disease‐causing genetic mutations, loci without specific mutations, and unconfirmed mutations, add up to a complex but interrelated group of neurobiologic pathways. Protein aggregation, proteasome dysfunction, mitochondrial inhibition and oxidative stress are some of the major theories of PD pathogenesis. Much of this information comes from working forward from disease‐causing genetic mutations. At the same time, toxin models of disease, human toxin exposure parkinsonism, and neuroepidemiology are also converging on a set of disease mechanisms. Mitochondrial dysfunction and oxidative stress is an example of how data from environmental exposure models and epidemiology fits with disease‐causing mutations and their protein products. Cutting edge PD neurotherapeutics will exploit targets in pathways clearly relevant to both inherited and sporadic parkinsonisms.
Novel Therapies for Multiple Sclerosis
Authors: Weber Martin S. , Zamvil Scott S.
Published: March 2007

As all currently approved drugs for treatment of multiple sclerosis (MS) are only partially effective and administered parenterally, the search for more efficient and preferentially oral treatment options must continue. Recent developments target specific inflammatory aspects in MS pathogenesis focusing on systemic immune dysfunction, blood‐brain barrier permeability and the inflammatory process within the CNS itself. In this chapter we will discuss the potential of newly developed monoclonal antibodies, which inhibit recruitment of activated immune cells into the CNS. The authors will also evaluate novel oral immunomodulators, which are primarily acting on the overactive immune system as the anticipated source of myelin‐reactive immune cells.
Bidirectional Ring‐Opening and Ring‐Closing of Cationic 1,2‐Dithienylcyclopentene Molecular Switches Triggered with Light or Electricity
Authors: Gorodetsky B. , Branda N. R.
Published: February 2007

Either light or electricity can be used to trigger the reversible cyclization reactions of three bis(N‐methylpyridinium)dithienylethene derivatives that differ from each other by the presence of either thiophene rings or methyl groups at the two carbon atoms of the photoresponsive hexatriene system involved in forming the new C–C bond. All three derivatives undergo ring‐closing isomerization reactions when irradiated with UV light (365 nm) or when electrochemically reduced (–1.0 V). All three derivatives can also be ring‐opened by irradiating them with visible light (> 490 nm) or by electrochemically oxidizing them (+1.5 V). The presence of additional thiophene rings attached to the two C2 ring positions of the dithienylethene (DTE) backbone enhances the electrochromic behavior, while methyl groups in these positions results in improved photochromic performance. The nature of these groups also greatly affects the thermal properties of the compounds in their ground states. Replacing each methyl group at the C2 ring positions with a thiophene ring systematically lowers the activation energy of spontaneous ring‐opening by 8 kJ mol–1, which correlates with the enhanced efficiency of the oxidative ring‐opening reactions and with the limited photochromism of the thiophene‐functionalized derivative.
When Small Is Different: Some Recent Advances in Concepts and Applications of Nanoscale Phenomena
Authors: Hodes G.
Published: February 2007

Reduction in size often does more than simply make things smaller. There are many properties of materials that undergo qualitative, often sudden, changes below a certain size scale. This Report first describes some of these size‐dependent properties. Following this general description, recent developments in a number of selected topics in nanoscience are covered. These topics are: luminescence from Au nanoparticles; Si (and related) nanoparticle luminescence; modification of optical absorption by surface adsorption on nanoparticles; and transistors (and some other devices) based on nanotubes and nanowires.
Knowledge for Generations
Authors: Gregory P.
Published: February 2007

For nearly twenty years, the Advanced Materials family of journals has been a rich source of knowledge for the materials science community. Returning as Editor‐in‐Chief, Peter Gregory reflects on this tradition of reporting outstanding research, and offers some views on maintaining these standards for future generations.
Time‐dependent behavior of a catalyst in a fluidized bed/cyclone circulation system
Authors: Klett Cornelis , Hartge Ernst‐Ulrich , Werther Joachim
Published: February 2007

The performance of a catalytic fluidized‐bed reactor is strongly dependent on the properties of the catalyst of which the particle‐size distribution is one. The main influences on the particle‐size distribution are attrition of the catalyst particles, and the classifying effect of the solids recovery system. In a fluidized‐bed reactor a particle will be subjected to attrition due to different mechanisms in different parts of the system, namely attrition by gas jets near the bottom of the fluidized bed, bubble‐induced attrition in the fluidized bed itself, and attrition during the passage through a cyclone. All these different attrition mechanisms are considered in this work by different mathematical models. It is known that a fresh catalyst is much more fragile and exhibits a much higher attrition rate at the beginning of exposure to mechanical stress than under steady‐state conditions. Depending on the mechanism the particles need different times or in the case of attrition in a cyclone a certain number of passages to reach a constant value of the attrition rate. In the fluidized‐bed system a particle will during its aging experience all the different attrition mechanisms. In order to summarize the effect of these stresses on the particle within the different parts of the fluidized‐bed system, the concept of the “stress history” has been developed, which allows a uniform treatment of the different attrition mechanisms. This concept has been implemented into an existing population balance model. Experiments with a FCC‐catalyst in a fluidized/bed‐cyclone circulation system are well described by this model. © 2007 American Institute of Chemical Engineers AIChE J, 2007
Mean‐field model for heat transfer in multichannel microreactors
Authors: Hardt Steffen , Baier Tobias
Published: February 2007

A reduced‐order model is developed, allowing for a fast computation of the temperature field in multichannel microreactors. The model regards the fluid and the solid phase as interpenetrating continua and incorporates heat exchange between the two phases via a heat‐transfer coefficient, characteristic for the channel geometry under study. The geometry of the channel walls determines the components of the thermal conductivity tensor, which govern conductive heat transfer to the envelope of the reactor. The mean‐field model is solved numerically for a test case inspired from practical applications. Parallel to that, a detailed model based on standard methods of computational fluid dynamics is set up with the purpose to benchmark the results of the mean‐field model. This full model incorporates the geometric details of the multichannel reactor and contains considerably more degrees of freedom than the mean‐field model, resulting in a computational effort that is larger by at least a factor of several hundred. It is found that the temperature fields computed with the two models agree up to maximum deviations of about 3 K on a scale of 35 K. Thus, the mean‐field model appears as an efficient tool to evaluate the thermal performance of multichannel microreactors, especially in the context of parameter studies or system optimization. © 2007 American Institute of Chemical Engineers AIChE J, 2007
Inflammatory progressive multifocal leukoencephalopathy in human immunodeficiency virus–negative patients
Authors: Huang DeRen , Cossoy Michael , Li Meizhang , Choi Dean , Taege Alan , Staugaitis Susan M. , Rehm Susan , Ransohoff Richard M.
Published: February 2007

Objective

Inflammatory progressive multifocal leukoencephalopathy (iPML) with enhancing magnetic resonance imaging (MRI) lesions and leukocyte infiltration occurs in human immunodeficiency virus (HIV)–infected individuals after highly active antiretroviral therapy (HAART) treatment. MRI diagnostic criteria for PML suggest that iPML does not occur in HIV‐negative individuals.

Methods

We studied pathologically proved PML (12 by biopsy, 9 with MRI, 32 at autopsy).

Results

HIV‐negative (2/5) and ‐positive (2/4) PML patients had enhancing MRI lesions, correlated with CD3+ lymphocyte infiltration. Inflammatory infiltrates occurred in the majority of HIV‐negative (7/8) and HIV‐positive/HAART (17/20) cases (p > 0.2), but in only 2 of 16 HIV‐positive/non‐HAART cases (p < 0.001).

Interpretation

iPML showed radiographic and pathological similarity in HIV‐positive/HAART and HIV‐negative patients. HIV‐negative iPML necessitates further consideration of MRI criteria for PML. Ann Neurol 2007
Tribological behavior of epoxy composites containing reactive SiC nanoparticles
Authors: Luo Ying , Zhi Rong Min , Qiu Zhang Ming
Published: February 2007

The present article evaluated the sliding wear behaviors of epoxy and its composites filled with SiC nanoparticles. Polyglycidyl methacrylate (PGMA) and a copolymer of glycidyl methacrylate and styrene were grafted onto the nanoparticles as a measure of surface pretreatment, respectively. The grafted polymers were selected because the epoxide groups on PGMA would take part in the curing reaction of epoxy resin and covalently connect the nanoparticles with the matrix, while styrene acted as a copolymerized monomer to adjust the amount of the reactive groups of the grafted macromolecular chains, and hence the compatibility between the grafted polymers and the matrix. In comparison to the composites filled with untreated nano‐SiC particles, the composites with the grafted nano‐SiC exhibit improved sliding wear resistance and reduced frictional coefficient owing to the chemical bonding at the filler/matrix interface. The results were analyzed in terms of structure‐properties relationship of the composites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2608–2619, 2007
Preparation and surface activity of biodegradable polymeric surfactants II: Dyeing properties of biodegradable dextrin derivatives in cotton dyeing
Authors: Wang Hong‐Jung , Chen Keng‐Ming
Published: February 2007

The biodegradability and dyeing properties of a series of dextrin‐derivative surfactants in direct‐dye cotton‐dyeing systems have been studied. It was found that these surfactants have good biodegradability, which is lacking in traditional dyeing auxiliaries. In dye‐surfactant systems, the degree of aggregation of direct dyes with surfactants was found to influence the rate of cotton dyeing. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2620–2624, 2007
Comb‐type methylsiloxane copolymers with diorganosilylene fragments as a lateral group
Authors: Mukbaniani O. , Tatrishvili T. , Mukbaniani N.
Published: February 2007

The catalytic dehydrocondensation reaction of α,ω‐bis(trimethylsiloxy)methylhydridesiloxane and of α,ω‐bis(trimethylsiloxy)methylhydridesiloxane‐dimethylsiloxane with α‐hydroxy‐ω‐trimethylsiloxydiorganosilylenes, in the presence of anhydrous caustic potassium, at 1:35 and 1:33 ratio of initial compounds has been investigated and polyorganosiloxanes with rigid polydiorganosilylenes fragment in the side chain, completely soluble in organic solvents, have been obtained. The catalytic dehydrocondensation reaction order, activation energies, and rate constants have been determined. The synthesized copolymers were characterized by thermogravimetric, gel permeation chromatographic, differential scanning calorimetric, and wide‐angle X‐ray analyses. It was shown that during modification of α,ω‐bis(trimethylsiloxy)methylhydridesiloxane‐dimethylsiloxane with α‐hydroxy‐ω‐trimethylsiloxydiorganosilylenes in synthesized block‐copolymers, microdomain structure (phase incompatibility) was observed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2161–2167, 2007
Shear rate dependence of viscosity and first normal stress difference of LCP/PET blends at solid and molten states of LCP
Authors: Hashmi S. A. R. , Kitano Takeshi
Published: February 2007

The liquid crystalline polymer (LCP) and polyethylene terephthalate (PET) were blended in an elastic melt extruder to make samples having 20, 40, 60, 80, and 100 wt % of LCP. Morphology of these samples was studied using scanning electron microscopy. The steady state shear viscosity (η), dynamic complex viscosity (η*) and first normal stress difference (N1) were evaluated and compared at two temperatures: 265°C, at which LCP was in solid state, and 285°C, at which LCP was in molten state. The PET was in molten state at both the temperatures. The shear viscosity of the studied blends displayed its dependence on composition and shear rate. A maxima was observed in viscosity versus composition plot corresponding to 80/20 LCP/PET blend. The N1 increased with LCP loading in PET and with the increased asymmetry of LCP droplets. The N1 also varied with the shear stress in two stages; the first stage demonstrated elastic deformation, whereas second stage displayed dominant plastic deformation of LCP droplets. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2212–2218, 2007
Formation of new thermoreactive polysiloxanes
Authors: Mukbaniani O. , Tatrishvili T. , Titvinidze G. , Mukbaniani N.
Published: February 2007

Hydrosilylation of α,ω‐bis(trimethylsiloxy)methylhydridesiloxane to propargyl alcohol in the presence of catalyst, platinum hydrochloric acid, was performed at several temperatures. Comb‐type methylsiloxane oligomers with substituted reactive groups in the side chain have been obtained. At the high stages of reaction, gelation takes place. Except hydrosilylation, also proceeds dehydrocondensation reaction with low yield. The synthesized oligomers were characterized by 1H‐NMR spectroscopy. Calculations by quantum‐mechanical semiempirical AM1 method for modeling reaction between methyldimethoxysilane [Me(MeO)2SiH] and propargyl alcohol were performed for fully characterization of hydride addition of polymethylhydrosiloxane to propargyl alcohol. For all initial, intermediate, and final products enthalpies of formation as a function of the distance between CSi bonds are calculated. Comb‐type oligomers were characterized by gel‐permeation chromatography, differential scanning calorimetry, thermogravimetry, and wide‐angle X‐ray diffractometry analyses. Crosslinking of synthesized oligomer using γ‐aminopropyltriethoxysilane was investigated and studied using DSC and TGA. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2168–2173, 2007
Synthesis of poly(o‐toluidine) in the presence of magnetic field and dysprosium chloride
Authors: Kan Jinqing , Tang Rong , Zhang Ya
Published: February 2007

The poly‐o‐toluidine (POT) was prepared under different magnetization in solution containing 0.5 mol dm−3o‐toluidine, 1.0 mol dm−3 HCl with and without 0.5 mol dm−3 DyCl3, respectively. Their conductivity, UV–vis, FTIR spectra, X‐ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscope (SEM) were investigated. The results of conductivity showed that magnetic field and the cooperative effect of Dy3+ and magnetic field do obvious effect to conductivity of POT. Meantime, they also can make the energy for the π–π* transitions and quinoid ring transition in UV–vis spectra smaller. At high magnetization the peaks of POT due to QNH+B or BNH+B and CH out of plane on 1,4‐ring or 1,2,4‐ring disappeared in FTIR spectra. Magnetic field and Dy3+ can make three dimensions morphologies of the POT clear, but they scarcely affect the crystallinity of POT. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2174–2179, 2007
Fibers based on cellulose–silk fibroin blend
Authors: Marsano E. , Canetti M. , Conio G. , Corsini P. , Freddi G.
Published: February 2007

Fibers made of cellulose (CE) and silk fibroin (SF) are wet spun from solutions in N,N‐dimethylacetamide containing 7% LiCl (w/w). Different coagulation baths (water and ethanol) and spinning conditions are used. By using water as the coagulant, a partial dissolution of SF occurs and negligible variation of the mechanical properties of the CE–SF fibers with respect to the CE fibers is found. Fibers coagulated in ethanol are dimensionally homogeneous and show better properties. A modulus of about 13 GPa and elongation to break of 16% for the blend containing 30% (w/w) SF are obtained with a 20‐mm air gap. The fibers are characterized by FTIR micro‐Raman, scanning electron microscopy, and wide‐ and small‐angle X‐ray analyses. In particular, the X‐ray results show that CE–SF fibers are amorphous with a homogeneous dispersion of small SF domains (1.3 nm) in the CE matrix. These results confirm the good compatibility between the two natural polymers. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2187–2196, 2007
Novel heat‐conductive composite silicone rubber
Authors: Zhou Wenying , Qi Shuhua , Tu Chunchao , Zhao Hongzhen
Published: February 2007

The silicone rubber with good thermal conductivity and electrical insulation was obtained by taking vinyl endblocked polymethylsiloxane as basic gum and thermally conductive, but electrically insulating hybrid Al2O3 powder as fillers. The effects of the amount of Al2O3 on the thermal conductivity, coefficient of thermal expansion (CTE), heat stability, and mechanical properties of the silicone rubber were investigated, and it was found that the thermal conductivity and heat stability increased, but the CTE decreased with increasing Al2O3 fillers content. The silicone rubber filled with hybrid Al2O3 fillers exhibited higher thermal conductivity compared with that filled with single particle size. Furthermore, a new type of thermally conductive silicone rubber composites, possessing thermal conductivity of 0.92 W/mK, good electrical insulation, and mechanical properties, was developed using electrical glass cloth as reinforcement. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2478–2483, 2007
Preparation and properties of modified PHEMA hydrogel with sulfonated PEG graft
Authors: Jung Young Pil , Kim Ji‐Heung , Lee Doo Sung , Kim Young Ha
Published: February 2007

A novel poly(ethylene glycol) (PEG) macromer with a methacryloyl and sulfonic acid group at each end of the chain was prepared. Modified hydroxyethyl methacrylate (HEMA) based hydrogels were synthesized by crosslinking polymerization of HEMA in the presence of the above‐mentioned PEG macromer. The effect of the sulfonated PEG graft was examined by comparing the swelling properties with those of a pure poly(hydroxyethyl methacrylate) (PHEMA) hydrogel. The modified PHEMA hydrogel exhibited increasing water absorbency with increasing sulfonated PEG content up to 15 wt %. These hydrogels with the sulfonated PEG graft exhibited a more hydrophilic character than the pure PHEMA gel. Also the swelling degree varied slightly with pH, showing increased swelling at higher pH probably due to the presence of the anionic sulfonate group on the PEG end chain. In addition, the protein adsorption test showed a lower level of fibrinogen adsorption from the sulfonated poly(ethylene glycol) (SPEG) modified gel than on the homo PHEMA hydrogel. Interestingly, scanning electron microscopy showed that the porous and rather uniform morphology of the gels changed with increasing sulfonated PEG content in PHEMA. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2484–2489, 2007
Synthesis and interfacial properties of aminosilane derivative of acrylated epoxidized soybean oil
Authors: Çolak Semra , Küsefoğlu Selim H.
Published: February 2007

In this study silanized acrylated epoxidized soybean oil (silanized‐AESO), a multifunctional monomer, was synthesized by reacting acrylated epoxidized soybean oil with 3‐Aminopropyltriethoxysilane via a Michael addition reaction using less than equivalent amount of the silane. The characterization of silanized‐AESO was done by NMR and IR spectroscopy. Free radically initiated homopolymer of silanized‐AESO was synthesized by using the residual acrylate groups. The silanized‐AESO homopolymer was characterized by IR spectroscopy. The interfacial adhesion of the polymer on glass surface before and after moisture cure was measured according to ASTM D 4541 Pull‐Off Adhesion Test. After moisture curing process, an approximate of eightfold improvement was observed in the adhesion strength. Prolonged exposure to 92% humidity for 48 h caused to approximately 15% decrease in the adhesion strength. Silanized‐AESO was copolymerized with styrene in 1 : 1 weight ratio via radical polymerization. The effect of increased crosslink density upon moisture cure on the mechanical and physical properties of silanized‐AESO‐styrene copolymer was analyzed by DMA (Dynamic Mechanical Analysis), swelling, and surface hardness tests. Upon moisture cure 35% improvement was observed in the storage modulus because of the increase in the crosslink density. According to tan δ curves and surface hardness tests, silanized‐AESO‐styrene copolymer shows heterogeneous morphology in crosslinked areas. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2244–2253, 2007
(CO2 + 2‐propanol) mixture as a foaming agent for polystyrene: A simple thermodynamic model for the high pressure VLE‐phase diagrams taking into account the foam vitrification
Authors: Dondero Marco , Carella José , Borrajo Julio
Published: February 2007

The equation of state model developed by Lacombe and Sanchez (J Phys Chem 1976, 80, 2352) is used in the form proposed later by Sanchez and Stone (Polymer Blends, Vol. 1: Formulation, 2000; Chapter 2) to correlate experimental vapor‐liquid equilibrium (VLE) data for the three binaries and the ternary systems. Experimental data from the binary systems carbon dioxide‐isopropyl alcohol (CO2‐IPrOH), isopropyl alcohol‐polystyrene (IPrOH‐PS), and carbon dioxide‐polystyrene (CO2‐PS) are used to calculate VLE properties for the ternary system CO2‐IPrOH‐PS. Two‐dimensional VLE‐phase diagrams were calculated and used to describe from a thermodynamic point of view the pressure, volume, and temperature values that characterize a thermoplastic foam evolution process, from the extruder to the foaming die. For different initial mixture CO2 + IPrOH concentrations, pressure reduction produces liquid foaming until the vitrification curve arrests the final foam volume expansion. The dependence of the vitreous transition with the system CO2 + IPrOH concentration while foaming is represented by the Chow (Macromolecules 1980, 13, 362) equation. The calculation procedure is proposed as a design tool to reduce the amount of experimental data usually needed as a requirement previous to the design stage. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2663–2671, 2007
Pyrolysis of epoxy resins and fire behavior of epoxy resin composites flame‐retarded with 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide additives
Authors: Schartel B. , Balabanovich A. I. , Braun U. , Knoll U. , Artner J. , Ciesielski M. , Döring M. , Perez R. , Sandler J. K. W. , Altstädt V. , Hoffmann T. , Pospiech D.
Published: February 2007

The pyrolysis of an epoxy resin and the fire behavior of corresponding carbon fiber‐reinforced composites, both flame‐retarded with either 10‐ethyl‐9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene 10‐oxide or 1,3,5‐tris[2‐(9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene 10‐oxide‐10‐)ethyl]1, 3,5‐triazine‐2,4,6(1H,3H,5H)‐trione, are investigated. The different fire retardancy mechanisms are discussed, and their influence on the fire properties assessed, in particular for flammability (limiting oxygen index, UL 94) and developing fires (cone calorimeter with different external heat fluxes of 35, 50, and 70 kW m−2). Adding the flame retardants containing 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide affects the fire behavior by both condensed phase and gas phase mechanisms. Interactions between the additives and the epoxy resin result in a change in the decomposition pathways and an increased char formation. The release of phosphorous products results in significant flame inhibition. The fire properties achieved are thus interesting with respect to industrial exploration. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2260–2269, 2007
Morphology and properties of PET/PA‐6/SiO2 ternary composites
Authors: Qu Cheng , Yang Hong , Liang Dong , Cao Wen , Fu Qiang
Published: February 2007

A kind of hydrophilic nano‐SiO2 was applied to poly(ethylene terephthalate)/polyamide‐6 (PA‐6) blends. Melt‐blended composites were prepared at various component ratios and different nano‐SiO2 levels. Mechanical, morphological, dynamic mechanical, and thermal tests were carried out to characterize the properties, morphology, and compatibilization of the composites. Increased impact strength, tensile strength, and modulus were observed by adding nano‐SiO2 particles in the blends. The nano‐SiO2 particles were found to be preferentially dispersed in PA‐6, resulting in an increase of glass transition temperature and crystallization of PA‐6. The mechanism of morphology and properties changes was discussed based on the selective dispersion of nano‐SiO2 particles in the blends. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2288–2296, 2007
Investigation of thermal degradation and flammability of polyamide‐6 and polyamide‐6 nanocomposites
Authors: Zong Ruowen , Hu Yuan , Liu Naian , Li Songyang , Liao Guangxuan
Published: February 2007

In this paper, polyamide‐6 and polyamide‐6 nanocomposites were prepared by direct melt intercalation technique. The thermal degradation behavior of both polyamide‐6 and polyamide‐6 clay nanocomposites has been studied. The apparent activation energy of the nanocomposites is almost the same with that of pure polymer under nitrogen, but the apparent activation energy of the nanocomposites is greatly enhanced in air atmosphere. This increasing trend coincides with the thermal analysis and the cone calorimeter results, which may suggest that the polymer/clay nanocomposites have a higher thermal stability and lower flammability. The kinetic analysis also indicates that the pyrolytic degradation and the thermal oxidative degradation of PA6 and PA6/OMT nanocomposites are two kinds of different reaction models. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2297–2303, 2007
Online study of the formation of PA6 droplets in PP matrix under shear flow
Authors: Yang Xiaodong , Zhu Yutian , Jiang Wei
Published: February 2007

Breakup process of polyamide 6 (PA6) in polypropylene (PP) matrix under shear flow was online studied by using a Linkam CSS 450 stage equipped with optical microscopy. Both tip streaming and fracture breakup modes of PA6 droplets were observed in this study. It was reported that the droplet would break up by tip streaming model when the radio of the droplet phase viscosity to the matrix phase viscosity (ηr = ηd/ηm) is smaller than 0.1 (Taylor, Proc R Soc London A 1934, 146, 501; Grace, Chem Eng Commun 1982, 14, 225; Bartok and Mason, J Colloid Sci 1959, 14, 13; Rumscheidt and Mason, J Colloid Sci 1961, 16, 238; de Bruijn, Chem Eng Sci 1993, 48, 277). However, the tip streaming model was observed even when the viscosity ratio was much greater than 0.1 (ηr = 1.9). In this study for the tip streaming mode, small droplets were ruptured from the tip of the mother droplet. On the other hand, the mother droplet was broken into two or more daughter droplets with one or several satellite droplets between them for the fracture mode. It was found that PA6 droplet was much elongated at first, and then broke up via tip streaming or fracture to form daughter droplets or small satellite droplets with the shape of fiber or ellipse. Stopping shearing, those elongated droplets began to shrink, and finally became spheres. Moreover, it was found that the average domain size of those PA6 spheres considerably decreased with increasing shear time. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2690–2695, 2007
Chemical modification of PVC into polymer‐supported oxazolinones and triazoles
Authors: Abdelaal Magdy Y. , Sobahi Tariq R.
Published: February 2007

PVC (P1) was converted into polymer‐supported oxazolinone and triazole derivatives after sequential chemical assembly of the reactive groups onto PVC. First, poly(vinyl chloride‐co‐vinylaminoaniline) (P2) was prepared by the reaction of PVC with p‐phenylenediamine. The primary aromatic amino group in P2 was diazotized and reacted with hippuric acid to form the supported oxazolinone derivative (P3) which could be converted into supported triazole derivatives (P4)–(P6) on further interaction with substituted anilines. The involved ring opening and preferred cyclization reactions have been clearly addressed based on spectroscopic and elemental analyses of the products. Also the ability for metal uptake has been roughly tested through the interaction with Cu(II) ions. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2304–2309, 2007
Study on morphological, rheological, and mechanical properties of PP/SEBS‐MA/SGF hybrid composites
Authors: Garakani M. Mohseni , Arefazar A. , Nazockdast H.
Published: February 2007

Hybrid composite samples composed of polypropylene as matrix, 20% short glass fibers (SGF) as reinforcement and varying amount of maleic anhydride (MA) grafted SEBS as compatibilizer and impact modifier were prepared by melt mixing in a modular twin screw extruder. The SEM examination performed on cryogenically fractured surfaces of hybrid samples showed a three‐phase type morphology in which SGF and rubber phase finely distributed in the PP matrix. SEM results also revealed that in the hybrid samples containing SEBS‐MA, the surface of the SGF are coated with a thin layer of SEBS‐MA, indicating a strong adhesion between SGF and matrix materials. The results of rheological studies showed nearly equal viscosity for compatible and incompatible hybrid samples. Tensile yield strength enhanced with increasing rubber content up to 10% above which it decreased and highest impact strength enhancement was obtained for sample containing 20% rubber. The impact strength of composites was found to be increased with increasing the SGF content. In final, it was shown that a good balance between stiffness and toughness could be achieved by adjusting the SGF and rubber content in this ternary system. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2704–2710, 2007
Polyelectrolyte complexes formed by hyperbranched poly(sulfone‐amine) hydrochlorate and poly(sodium acrylate)
Authors: Zhou Li , Yan Liangyu , Xue Jie , Chen Liang , Wang Yanping , Jia Zhifeng , Zhu Xinyuan , Yan Deyue
Published: February 2007

A new type of polyelectrolyte complexes formed by hyperbranched poly(sulfone‐amine) hydrochlorate and poly(sodium acrylate) has been reported. It has been found that the stoichiometry between polycation and polyanion is 1.16, which means that hyperbranched polyelectrolyte can also form the compact complexes in spite of the ill‐defined structure. Moreover, the effect of various parameters, such as the architecture of poly(sulfone‐amine), molecular weight of polymer, concentration and low molecular salt, on the complexation is also discussed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2323–2329, 2007
Effect of reacetylation and degradation on the chemical and crystal structures of chitosan
Authors: Qun Gao , Ajun Wan , Yong Zhang
Published: February 2007

The changes of chemical and crystal structures of the reacetylation and degraded chitosans caused by sonication, acid hydrolysis, and H2O2 oxidation were studied systematically. During the reacetylation of chitosan, acetic anhydride can result in the degradation of chitosan when its concentration exceeds a certain value (the acetic anhydride/amine ratio > 0.3). Three crystalline polymorphs appear during the reacetylation process of chitosans that the degree of deacetylation (DD) range from 94 to 5%. The increase of acetyl group leads to a notable crystal structure transition from crystal “Form II” with constrained chain conformation to “Form I” having a more extended chain structure, and finally to a crystalline form similar to that of chitin. The DD of chitosan is not altered by sonication and acid hydrolysis, but decrease obviously because of deamination occurring in the chain scission of H2O2 oxidation. The crystallinity increases with the decreasing of molecular weight for sonication and acid hydrolysis, whereas a deeper degradation by H2O2 will decrease the cystallinity. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2720–2728, 2007
Copolymers of aniline and o‐methoxyaniline. II. Thermoanalytical studies
Authors: Tsocheva Dimitrinka , Mokreva Pavlina , Terlemezyan Levon
Published: February 2007

A study on the thermal stability, thermodynamical parameters, especially relaxation transition temperature (Tg), and their change upon irreversible reactions (crosslinking, postpolymerization, decomposition, etc.) taking place on heating of the undoped homo‐ and copolymers of aniline and o‐methoxyaniline was performed by using differential scanning calorimetry. It was found that polyaniline and its oligomers might be responsible for the postpolymerization process observed on heating thermograms of the polymers in their emeraldine base form. It can be stated that the proceeding of this process appears to be a reason for the higher thermal stability of polyaniline when compared with poly(o‐methoxyaniline). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2729–2734, 2007
Waste polystyrene foam‐graft‐acrylic acid/montmorillonite superabsorbent nanocomposite
Authors: Liu Ping‐Sheng , Li Li , Zhou Ning‐Lin , Zhang Jun , Wei Shao‐Hua , Shen Jian
Published: February 2007

A novel superabsorbent nanocomposite based on partially neutralized acrylic acid, waste polystyrene foam, and sodium type montmorillonite (Na‐MMT) powder was synthesized through emulsion polymerization using N, N′‐methylenebisacrylamide as a crosslinker, 2,2′‐azo‐bisiso‐butyronitrile, ammonium persulfate, and sodium sulfite as mixed redox initiators. The effects of such factors as amount of Na‐MMT, crosslinker, initiator, and neutralization degree on water absorbency of the superabsorbent were investigated. The composites were characterized by Fourier transform infrared spectroscope, X‐ray diffraction, thermo gravimetric analysis, and scanning electron microscope. The results show that acrylic acid monomer successfully grafted onto the polystyrene chain, the layers of Na‐MMT were exfoliated and dispersed in the composite at nano size after copolymerization. The introduction of waste polystyrene foam in the composite increased the water absorbency rate. The addition of Na‐MMT not only enhanced the thermal stability of the composites but also increased its water absorbency, and the optimal water absorbencies of distilled water and saline water (wNaCl = 0.9%) of the nanocomposites were more than 1180 g H2O/g and 72.6 g H2O/g, respectively. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2341–2349, 2007