bluuebunny/crossref_metadata_2025 huggingface dataset:
Arrested development of secondary sexual adornments in subordinate adult male mandrills (Mandrillus sphinx)
Authors: Setchell Joanna M. , Dixson Alan F.
Published: August 2002

Previous studies of semifree‐ranging mandrills identified two morphological and social variants of the adult male, based on behavioral and secondary sexual characteristics. “Fatted” males are social, with highly developed sex skin coloration, large testes, high plasma testosterone levels, and fat rumps; while “nonfatted” males are peripheral or solitary, with paler sex skin, smaller testes, lower plasma testosterone, and slimmer rumps. We present a detailed study of morphology and group association for 10 adult male mandrills, living in two semifree‐ranging groups in Gabon, in order to relate differences between males to dominance rank. The results show that rather than existing as two distinct morphotypes, male mandrills represent a continuous spectrum of possibilities between social males with fully developed secondary sexual characteristics, and solitary males with muted secondary sexual characteristics. Alpha males (N = 2) had the highest testosterone levels, the most colorful sex skin, and the most active sternal glands, and were the only males to spend 100% of their time with the social group. Rank relationships between nonalpha males (N = 8) were not always clear, but all subordinate males had lower testosterone levels and less development of the secondary sexual adornments, and were less group‐associated than alpha males. These findings suggest that only alpha males have sufficient testosterone to develop full secondary sexual characteristics, and we propose possible socioendocrine mechanisms underlying the suppression of testosterone and secondary sexual development in subordinate adults. We discuss differences in secondary sexual development in relation to reproductive strategies, and discuss the evolution of alternative reproductive morphs in primates. Am J Phys Anthropol 115:245–252, 2001. © 2001 Wiley‐Liss, Inc.
Brief communication: Choice of washing method of hair samples for trace element analysis in environmental studies
Authors: Sen Jaydip , Das Chaudhuri A.B.
Published: August 2002

Determination of inseparable exogenous and endogenous levels of toxic trace elements such as lead in human scalp hair has been used to understand and assess population exposure to such elements. For any such analysis, washing of the hair samples to remove superficial contamination is the foremost requirement. However, the use of such washing methods prior to elemental analysis removes minute quantities of trace elements from the hair strands. This degree of loss is dependent on the washing method employed. In the present study, the element lead has been determined in human scalp hair after three methods of hair washing. It is apparent that the nonionic detergent‐acetone method is best suited for securing valid lead analysis results in human scalp hair. Am J Phys Anthropol 115:289–291, 2001. © 2001 Wiley‐Liss, Inc.
Apolipoprotein E affects the central nervous system response to injury and the development of cerebral edema
Authors: Lynch John R. , Pineda Jose A. , Morgan Duncan , Zhang Lin , Warner David S. , Benveniste Helen , Laskowitz Daniel T.
Published: August 2002

Apolipoprotein E has been implicated in modifying neurological outcome after traumatic brain injury, although the mechanisms by which this occurs remain poorly defined. To investigate the role of endogenous apolipoprotein E following acute brain injury, noninvasive magnetic resonance imaging was performed on anesthetized mice following closed head injury. Effacement of the lateral ventricle was used as a radiographic surrogate for cerebral edema. At 24 hours following injury, apolipoprotein E‐deficient animals had a greater degree of cerebral edema as compared to matched controls. In addition, the brains of apolipoprotein E‐deficient animals had a significantly greater upregulation of tissue necrosis factor α messenger ribonucleic acid as compared to controls as early as 1‐hr post injury. Thus, modulation of the endogenous central nervous system inflammatory response may be one mechanism by which apolipoprotein E affects outcome following acute brain injury.
A recessive form of central core disease, transiently presenting as multi‐minicore disease, is associated with a homozygous mutation in the ryanodine receptor type 1 gene
Authors: Ferreiro Ana , Monnier Nicole , Romero Norma B. , Leroy Jean‐Paul , Bönnemann Carsten , Haenggeli Charles‐Antoine , Straub Volker , Voss Wolfgang D. , Nivoche Yves , Jungbluth Heinz , Lemainque Arnaud , Voit Thomas , Lunardi Joël , Fardeau Michel , Guicheney Pascale
Published: August 2002

Multi‐minicore disease is an autosomal recessive congenital myopathy characterized by the presence of multiple, short‐length core lesions (minicores) in both muscle fiber types. These lesions being nonspecific and the clinical phenotype being heterogeneous, multi‐minicore disease boundaries remain unclear. To identify its genetic basis, we performed a genome‐wide screening in a consanguineous Algerian family in which three children presented in infancy with moderate weakness predominant in axial muscles, pelvic girdle and hands, joint hyperlaxity (hand involvement phenotype), and multiple minicores. We mapped the disease to chromosome 19q13 in this family and, subsequently, in three additional families showing a similar phenotype, with a maximum LOD score of 5.19 for D19S570. This locus was excluded in 16 other multi‐minicore disease families with predominantly axial weakness, scoliosis, and respiratory insufficiency (“classical” phenotype). In the Algerian family, we identified a novel homozygous missense mutation (P3527S) in the ryanodine receptor type 1 gene, a positional candidate gene responsible for the autosomal dominant congenital myopathy central core disease. New muscle biopsies from the three patients at adulthood demonstrated typical central core disease with rods; no cores were found in the healthy parents. This subgroup of families linked to 19q13 represents the first variant of central core disease with genetically proven recessive inheritance and transient presentation as multi‐minicore disease.
Elevated serum and cerebrospinal fluid levels of soluble human herpesvirus type 6 cellular receptor, membrane cofactor protein, in patients with multiple sclerosis
Authors: Soldan Samantha S. , Fogdell‐Hahn Anna , Brennan Meghan B. , Mittleman Barbara B. , Ballerini Clara , Massacesi Luca , Seya Tsukasa , McFarland Henry F. , Jacobson Steven
Published: August 2002

Membrane cofactor protein (CD46) is a member of a family of glycoproteins that are regulators of complement and prevent activation of complement on autologous cells. Recently, CD46 has been identified as the cellular receptor for human herpesvirus Type 6 (HHV‐6). Elevated levels of soluble CD46 have been described in several autoimmune disorders and may be implicated in the pathogenesis of these diseases. As several reports have supported an association of HHV‐6 and multiple sclerosis, it was of interest to compare levels of soluble CD46 in the sera of MS patients to that of healthy controls, other neurological disease controls, and other inflammatory disease controls. Using an immunoaffinity column comprised of immobilized monoclonal antibodies to CD46, serum levels of soluble CD46 were found to be significantly elevated in multiple sclerosis patients compared with healthy and other neurological disease controls. Moreover, multiple sclerosis patients who tested positive for HHV‐6 DNA in serum had significantly elevated levels of soluble CD46 in their serum compared with those who were negative for HHV‐6 DNA. A significant increase in soluble CD46 was also found in the serum of other inflammatory disease controls tested compared with healthy controls. Additionally, a significant correlation was demonstrated between levels of soluble CD46 in the serum and cerebrospinal fluid of multiple sclerosis patients. Collectively, these data suggest that elevated levels of soluble CD46 may contribute to the pathogenesis of inflammatory diseases, including MS.
Individual blood–brain barrier phenylalanine transport determines clinical outcome in phenylketonuria
Authors: Weglage Josef , Wiedermann Dirk , Denecke Jonas , Feldmann Reinhold , Koch Hans‐Georg , Ullrich Kurt , Harms Erik , Möller Harald E.
Published: August 2002

Different clinical outcomes in spite of comparable dietary controls are well known in patients with phenylketonuria. Currently, reasons for this phenomenon are unknown. Kinetic investigations in 15 patients with classic phenylketonuria were performed using in vivo nuclear magnetic resonance spectroscopy before and after an oral phenylalanine load (100 mg/kg body weight). Patients' brain phenylalanine (Phe) concentrations were quite different in spite of similar blood Phe levels. Interindividual variations of the apparent transport Michaelis constant, Kt,app, covered a range from 0.10 to 1.03mmol/L. The ratio of the maximal transport velocity, Tmax, over the intracerebral consumption rate, Vmet, varied between 2.61 and 14.0. Both parameters as well as the preload brain Phe levels correlated significantly with the degree of cerebral white matter abnormalities on magnetic resonance images. Correlations of Kt,app, Tmax/Vmet, and the preload brain Phe levels with patients' intelligence scores approached significance. In conclusion, blood–brain barrier Phe transport characteristics and the resultant brain Phe levels seem to be causative factors for the individual clinical outcome in phenylketonuria. This observation may lead to individual dietary recommendations in the future.
Adult‐onset leukoencephalopathy with vanishing white matter presenting with dementia
Authors: Prass Konstantin , Brück Wolfgang , Schröder Nicolas W. J. , Bender Andreas , Prass Maria , Wolf Tilo , Van Der Knaap Marjo S. , Zschenderlein Rolf
Published: August 2002

We report on a case of dementia and extensive cerebral white matter abnormalities seen on magnetic resonance images which meet the criteria for leukoencephalopathy with vanishing white matter. This is an inherited condition that was first thought to occur only in children. Our patient shows that vanishing white matter should be considered in adult patients with early‐onset dementia and extensive white matter changes seen on magnetic resonance images.
Process optimization of sweet potato pulp‐based biodegradable plastics using response surface methodology
Authors: Kim Jun T. , Cha Dong S. , Lee Gee D. , Park Tae W. , Kwon Dong K. , Park Hyun J.
Published: August 2002

Biodegradable plastics were produced from sweet potato pulp (SPP) and cationic starch (CS) or chitosan composite (CC) by compression molding and their mechanical properties were tested. A universal testing machine, Rockwell hardness tester, and Izod impact tester were used for testing the mechanical properties (flexural strength, Rockwell hardness, and Izod strength) of the plastics. A central composite second‐order design was used to study the effects of temperature, time, and moisture content on the flexural strength, Rockwell hardness, and Izod strength of SPP/CS and SPP/CC blended plastics. The flexural strength, Rockwell hardness, and Izod strength of SPP‐based plastics was 101.1–305.9 kg/cm2, R29.0–R96.7, and 0.6–3.0 kg cm cm−2, respectively. Regression analysis predicted the optimal mechanical properties (flexural strength, Rockwell hardness, and Izod strength) to be attained with a 150–160°C temperature, 15–20‐min reaction time, and 20–23% moisture content. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 423–434, 2002
Thermosetting resin system based on novolak and bismaleimide for resin‐transfer molding
Authors: Yan Yehai , Shi Xianming , Liu Jinge , Zhao Tong , Yu Yunzhao
Published: August 2002

A thermosetting resin system for resin‐transfer molding based on novolak and bismaleimide (BMI) was developed. The novolak resin was allylated and BMI was used as the curing agent, and allyl phenyl ether, as the diluent. The viscosity–temperature curve and the viscosity–time curve were used to characterize the processing property of the resin system. The resin system had a long pot life at the injection temperature. Based on the DSC data, a regime for the curing and postcuring cycles was established. The cured resin showed outstanding heat resistance and good flexural properties. Composites based on the resin system and woven glass fabric were fabricated using RTM technology. The composites showed very good flexural properties at room temperature and high retention rates at 200 and 300°C. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1651–1657, 2002
Polymer/silica nanoscale hybrids through sol–gel method involving emulsion polymers. I. Morphology of poly(butyl methacrylate)/SiO2
Authors: Tong Xin , Tang Tao , Zhang Qingling , Feng Zhiliu , Huang Baotong
Published: August 2002

In this article, we report on an approach of using an emulsion polymerized polymer in preparing organic–inorganic nanocomposites through a sol–gel technique. By mixing a polymer emulsion with prehydrolyzed tetraethoxysilane transparent poly(butyl methacrylate)/SiO2, nanocomposites were prepared as shown by TEM. AFM, FTIR, and XPS results show that there is a strong interaction between polymer latex particles and the SiO2 network. Comparison of the emulsion method with a traditional solution method shows that nanocomposites can be prepared by both methods, but there is some difference in their morphology and properties. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 446–454, 2002
The interaction mechanism between microorganisms and substrate in the biodegradation of polycaprolactone
Authors: Lefèvre Carine , Tidjani Adams , Vander Wauven Corinne , David Christiane
Published: August 2002

The present work concerns the interplay of the degradation mechanism and the nature of the interaction between microorganisms and substrate. The biodegradation of polycaprolactone films by a pure strain of microorganisms isolated from an industrial composting unit for household refuse was studied in minimal medium with the polymer as sole carbon source. In conditions where the polymer surface is colonized and a biofilm is formed (under a low stirring rate), polymer weight loss is limited, whereas total degradation is observed when stirring conditions prevent biofilm formation. In the first case, holes are observed in the degraded film and a polysaccharide responsible for microorganism adhesion was identified by FTIR. SEM observation of the polymer surface as a function of the degradation time suggests that the crystalline and amorphous phase are degraded at about the same rate in the first case, whereas the amorphous phase is preferentially degraded in the latter. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1334–1340, 2002
Photoinduced living cationic polymerization of tetrahydrofuran(IV): Syringe method
Authors: Choi Jia , Kwon Soonhong , Mah Soukil
Published: August 2002

The living nature of cationic poly(tetrahydrofuran), which is generated by the addition of the photolytic products of diphenyliodonium hexafluorophosphate (initiator) via syringe, was investigated in connection with the direct polymerization method in which polymerization of tetrahydrofuran is carried out in the presence of the initiator. Although the living nature of the polymerization (i.e., the linear relationship between the percentage of conversion and the molecular weight of the resulting polymer) is observed in the syringe method because of the absence of chain transfer or termination, unexceptionally, a lower rate of polymerization and higher molecular weights of the resulting polymers were observed in the syringe method when compared with those of the corresponding direct polymerization method. This leads us to the conclusion that the living nature is ascribed to the stabilization of the propagating cationic species due to ion pair formation with the less‐nucleophilic complex metal halide anion (PF), and the decreased rate of polymerization and higher molecular weight in the syringe method is attributed to the partial loss of the activity of the cationic species because of the nucleophilic attack of basic impurities, such as water, introduced to the system in the syringe manipulation. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2082–2087, 2002
Nanocomposite structure depending on the degree of surface treatment of layered silicate
Authors: Suh Duck Jong , Park O Ok
Published: August 2002

Nanocomposite structures depending on the degree of surface modification of montmorillonite (MMT) were studied. To change the degree of surface modification, MMT was treated with a controlled amount of stearylamine. The structures of MMTs and nanocomposites were investigated by X‐ray diffraction. To confirm the extent of surface coverage of the stearylamine as a organophilic modifier, TGA and elemental analysis experiments were performed. Different structures (intercalated or exfoliated) of a polymer/clay nanocomposite were obtained according to the interfacial characteristics between the polymer chains and the clay by controlling the degree of surface coverage. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2143–2147, 2002
Dye‐affinity microbeads for removal of phenols and nitrophenols from aquatic systems
Authors: Denizli Adil , Ökan Güleren , Uçar Mustafa
Published: August 2002

Alkali Blue 6B attached poly(2‐hydroxyethyl methacrylate) (PHEMA) microbeads were investigated as dye‐affinity adsorbents for the removal of phenol and nitrophenols (i.e., 2‐nitrophenol, 4‐nitrophenol, and 2,4‐dinitrophenol) from aqueous solutions. PHEMA microbeads were prepared by radical‐suspension polymerization of HEMA in the presence of azobisisobutyronitrile as the initiator. These microbeads with a swelling ratio of 55% and carrying 23.6 μmol Alkali Blue 6B/g polymer were then used in the removal of phenol and nitrophenols from aqueous media. The adsorption was fast in all cases (20‐min equilibrium time). The maximum adsorptions of phenols onto the microbeads carrying Alkali Blue 6B were 145.2 μmol/g for phenol, 87.8 μmol/g for 2,4‐dinitrophenol, 112.6 μmol/g for 4‐nitrophenol, and 104.3 μmol/g for 2‐nitrophenol. The affinity order was phenol > 4‐nitrophenol > 2‐nitrophenol > 2,4‐dinitrophenol. The adsorption of nitrophenols decreased with increasing pH. Desorption of nitrophenols was achieved using a 30% (v/v) methanol solution. The microbeads carrying Alkali Blue 6B are suitable for repeated use for more than five cycles without a noticeable loss of adsorption capacity. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2411–2418, 2002
Effect of compatibility of cellulose acetate/poly(vinyl butyral) blends on pervaporation behavior of their membranes for methanol/methyl tert‐butyl ether mixture
Authors: Qian J. W. , Chen H. L. , Zhang L. , Qin S. H. , Wang M.
Published: August 2002

Binary blends and their blend membranes of cellulose acetate (CA) and poly(vinyl butyral) (PVB) are prepared by solution blending. The compatibility of the blends is studied by viscometry and Fourier transform IR. It is found that the incompatibility of the blends is markedly manifested when the weight fraction of PVB in the CA/PVB blends (WPVB) is located at higher regions. On the other hand, compatibility is obtained for the CA/PVB blends with lower WPVB values, especially at about 0.2. This compatibility is believed to play a key role in the good pervaporation behavior of CA/PVB blend membranes. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2434–2439, 2002
Electrical resistivity of carbon black filled high‐density polyethylene composites
Authors: Lee Myong‐Goo , Nho Young Chang
Published: August 2002

The electrical resistivity of high‐density polyethylene (HDPE) loaded with carbon black (CB) blends was evaluated as a function of the blending time and the melt index of HDPE. The relationship between the positive temperature coefficient effect and the room temperature volume resistivity was investigated. The positive temperature coefficient effect and reproducibility were improved significantly when the blending time of HDPE and CB was comparatively long. The effects of 60Co γ‐ray and electron beam irradiation on the positive and negative temperature coefficient behavior of the blends were studied. The effect of thermal aging on the volume resistivity was studied to ascertain the structural stability. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2440–2446, 2002
Advanced underfill for high thermal reliability
Authors: Bae Jong‐Woo , Kim Wonho , Park Sang‐Wook , Ha Chang‐Sik , Lee Jin‐Kook
Published: August 2002

The key to the success of flip‐chip technology lies in the availability of sucessful underfill materials. However, the reliability of flip‐chip technology using current underfill materials is generally found to be lower than that of conventional wire‐bond connection packaging materials such as epoxy molding compound (EMC) because of the high coefficients of thermal expansion (CTE) and moisture absorption of cured underfill material. In this study desbimide (DBMI), which has a low melting point (about 80°C), was used in the underfill materials as a cohardener. As a result, DBMI‐added underfill can show excellent thermal reliability, which is due to the superior properties of the CTE, the elastic modulus, and water resistance. When the properties of a 2 wt % DBMI‐added underfill were compared with those of a typical underfill (epoxy/anhydride), the CTE value was reduced to less than one‐half at the solder reflow temperature (about 200°C), the elastic modulus was reduced to less than one‐half in the temperature region below the glass‐transition temperature, and the water resistance was improved twofold. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2617–2624, 2002
Electrosynthesis of free‐standing poly(para‐phenylene) films in mixed electrolytes of boron trifluoride diethyl etherate and trifluoroacetic acid on stainless steel electrode
Authors: Li Chun , Chen Fengen , Shi Gaoquan , Xu Jingkun , Xu Zhengjiang
Published: August 2002

Free‐standing poly(para‐phenylene) (PPP) films have been electrosynthesized by direct oxidation of benzene on stainless steel electrode in mixed e1ectrolytes of boron trifluoride diethy1 etherate (BFEE) and trifluoroacetic acid (TFA). The oxidation potential of the monomer in these media is lower than those in the neutral media. Increasing the content of TFA in the mixed electrolyte can effective1y decrease the oxidation potential and increase the coup1ing rate of the monomer. The films obtained from these media were very shiny and flexible, and could easily be processed into various shapes by conventional mechanical methods. The films had a 1inear chain structure, and their degree of polymerization could be improved by increasing the TFA content in the mixed electrolyte. Moreover, the films had a fairly good thermal stability. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2462–2466, 2002
Novel electron beam‐modified surface‐coated silica fillers: Physical and chemical characteristics
Authors: Ray Sudip , Bhowmick Anil K.
Published: August 2002

A novel process of surface modification of silica fillers has been performed by coating with an acrylate monomer, trimethylol propane triacrylate (TMPTA) and with a silane coupling agent, triethoxy vinyl silane (TEVS), followed by electron beam irradiation of these coated fillers. The surface‐modified fillers have been characterized by Fourier‐Transform Infrared Analysis (FTIR), Electron Spectroscopy for Chemical Analysis (ESCA), Contact angle measurements by dynamic wicking method, Scanning Electron Microscopy (SEM), Energy dispersive X‐ray spectroscopy (EDX), Transmission Electron Microscopy (TEM), Fractal studies, Thermogravimetric analysis (TGA), and X‐ray diffraction (XRD) studies. Presence of the acrylate and the silane coupling agent on the modified fillers is confirmed from the above studies. The contact angle measurements suggest a significant improvement in hydrophobicity of the treated fillers, which is supported by water flotation test. After irradiation and acrylate treatment an increase in filler aggregation is observed, which is not as significant in the case of silanized silica filler. However, XRD studies demonstrate that the entire modification process does not alter the bulk properties of the fillers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2255–2268, 2002
A new photopolymerization system for vinyl monomers
Authors: öz Nesri̇n , Akar Ahmet
Published: August 2002

A mixture of Ce+3 salt and an aminomethylene phosphonic acid, such as amino tri(methylene phosphonic acid) (ATMP), diethylene triamine penta(methylene phosphonic acid), N,N‐di(methylene phosphonic acid) ethanol amine, N,N‐di(methylene phosphonic acid)‐N‐methylamine, N‐oxo‐N,N,N‐tri(methylene phosphonic acid), or 1‐hydroxy‐ethylidene‐1,1‐diphosphonic acid, was used for the photopolymerization of acrylonitrile, vinyl acetate, acrylic acid, and styrene in water. Molecular weights of the polymers decreased with increasing concentration of both Ce+3 salt and ATMP. The effect of oxygen, light, pH, and the addition order on polymerization were also studied. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2494–2499, 2002
Interfacial interaction in AI(OH)3/polypropylene composites modified by insitu‐functionalized polypropylene
Authors: Mai Kancheng , Li Zhengjun , Qiu Yuxin , Zeng Hanmin
Published: August 2002

To investigate the interfacial interaction of AI(OH)3/polypropylene (PP) composites modified by in situ‐functionalized polypropylene (FPP), AI(OH)3/polypropylene (PP) composites containing a low AI(OH)3 content, modified by in situ‐grafted acrylic acid, were prepared by a one‐step melt‐extrusion process. The effect of in situ FPP on the crystallization and melting behavior, crystalline morphology of the composites, and interfacial interaction between the filler and PP was investigated. The crystallization and melting behavior and crystalline morphology of PP in the composites depended upon the interfacial physical [heterogeneous nucleation of AI(OH)3; cocrystallization and compabilitization of PP with in situ FPP] and the interfacial chemical interaction between both the components in the composites. FTIR results indicated that there exists a chemical reaction between AI(OH)3 and in situ FPP. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 110–120, 2002; DOI 10.1002/app.10270
Mechanical properties of thermoplastic starch/poly(hydroxy ester ether) blends: Effect of moisture during and after processing
Authors: Walia Parvinder S. , Lawton John W. , Shogren Randal L.
Published: August 2002

The mechanical properties of thermoplastic starch (TPS) and poly(hydroxy ester ether) (PHEE) blends were studied as a function of the starch concentration. The moisture level present during processing significantly affects the morphology. A dispersed droplet morphology was observed even at very high starch levels at low moisture levels. On the other hand, the dispersed phase was significantly deformed under high moisture conditions, leading to fibrillar and laminar types of morphologies at high starch levels. The change in morphology has a significant effect on the mechanical properties. The presence of elongated starch domains improved the tensile strength and modulus of the blends with no loss in ductility. The blend modulus could be effectively represented by the particular morphology present at any given starch concentration range, using a generalized form of Kerner's equation. The properties of the blends changed with the conditioning time and relative humidity (RH), due to the change in the moisture content of each phase. An attempt was made to express the blend modulus as a function of the relative modulus of the two phases, calculated at any given RH or conditioning time. The data could be shifted fairly well from one RH to another under equilibrium conditions. However, a shift from one conditioning time to another was difficult, owing to the slower kinetics of moisture exchange at higher amounts of PHEE, which has to be taken into account. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 121–131, 2002; DOI 10.1002/app.10271
Possible phosphorus‐bromine synergy in polyester‐cotton fabrics treated with tetrabromobisphenol‐A and diammonium phosphate
Authors: Lee Eui So
Published: August 2002

Polyester/cotton fabrics were treated with tetrabromobisphenol‐A (TBBA)/epichlorohydrin (EPI) aqueous solution, followed by being treated with diammonium phosphate (DAP)/urea solution. The optimum mole ratio of EPI to TBBA was determined. The synergism of TBBA and DAP was found to operate on the treated fabrics. The maximal synergism was obtained when the bath concentration of TBBA was equal to that of DAP. The mechanism of flame‐retardancy was analyzed by thermogravimetry and residue number. The flame‐retardancy of the polyester/cotton fabrics treated with TBBA/DAP was found operative mainly in the condensed‐phase mechanism. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 172–177, 2002; DOI 10.1002/app.10292
Effect of nonprotein polymers on water‐uptake properties of fish protein‐based hydrogel
Authors: Rathna G. V. N. , Damodaran Srinivasan
Published: August 2002

The effects of nonprotein polymers on the water‐swelling properties of fish protein‐based hydrogel were studied. Inclusion of carboxymethyl cellulose (CMC), poly(ethylene glycol) (PEG), poly(vinyl alcohol) (PVA), or guar gum at a 2.5% (w/w) level in an 80% ethylenediaminetetraacetic dianhydide (EDTAD)‐modified fish protein hydrogel (10% monomer concentration) significantly decreased the extent of water uptake of the hydrogel. Among these polymers, PVA exhibited the greatest inhibitory effect. The inhibitory effect of these polymers on the water uptake of fish protein hydrogel was apparently due to the thermodynamic incompatibility of these polymers with the fish protein gel network and the consequent effect on the extent of relaxation of the crosslinked polypeptide network. In contrast, inclusion of 60% EDTAD‐modified soy protein up to a level of 40% of the total protein in the gel did not affect the extent of the equilibrium water uptake of the gel. At higher levels, however, soy protein also decreased the amount of water uptake by the gel. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 45–51, 2002
Conductometric and viscometric investigation of poly(N‐vinylimidazole)‐metal ion complex formation
Authors: Pekel Nursel , Güner Alý , Güven Olgun
Published: August 2002

The complexation of copper (Cu2+), cobalt (Co2+), and cadmium (Cd2+) ions with poly(N‐vinylimidazole) (PVIm) and its protonated form in aqueous solution was studied conductometrically and viscometrically. From the conductometric and viscometric curves, it was found that four imidazole units were coordinated with one metal ion in the complex systems. Both studies showed that the complex formation tendency decreased in the following order: Cu2+ > Co2+ > Cd2+. Complex properties of metal ions with imidazole group were explained by referring to Pearson's treatment, as hard and soft acids and bases. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 376–384, 2002
Kinetics of wood phenolysis in the presence of HCL as catalyst
Authors: Acemioglu B. , Alma M. H.
Published: August 2002

Monarch birch wood (Betula maximowiczina Regel) wastes were phenolated in the presence of HCl as a catalyst at 60–150°C for various reaction times. Typical kinetic parameters along with percent reacted wood and phenol were determined by using kinetic models. In addition, according to the transition‐state theory the activation parameters of wood phenolysis was determined. The percent reacted wood wastes depicted that about 90% of the wood could be liquefied into phenol at a temperature of 150°C. However, about 30% of phenol was found to react with wood components. The kinetic studies showed that wood phenolysis with HCl catalyst at 60–150°C obviously followed a bimolecular type of second‐order reaction. Activation energy was found to be 13.438 kJ mol−1 from an Arrhenius plot. Furthermore, the findings related with activation enthalpy showed that the wood phenolysis had dominantly endothermic reaction nature. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1098–1103, 2002
Effect of lamp cycling on conversion and stress development in ultraviolet‐cured acrylate coatings
Authors: Vaessen Diane M. , Ngantung Frederyk A. , Palacio Manuel L. B. , Francis Lorraine F. , McCormick Alon V.
Published: August 2002

In radiation‐cured acrylate coatings, a high conversion of monomer is generally desired to improve hardness, prevent further slow reaction upon aging, and avoid surface toxicity; however, shrinkage and, consequently, stress in coatings tend to increase with conversion. One route to achieve high conversion while maintaining low coating stress is to promote stress relaxation. In this study, acrylate coatings were cured with a UV lamp that was cycled on and off, varying the period from 2 to 60 min while keeping the total dose constant. All samples reached nearly the same conversion, between 46 and 48% conversion of functional groups, as measured by FTIR spectroscopy. The coating stress (measured with cantilever deflection) at the end of the exposure cycles, however, was lowered from 8 MPa (tension) to less than 3 MPa (tension) as the period was decreased from 60 to 2 min. The cycling had no significant effect on either the coating hardness or the modulus, as measured by a Hysitron triboscope. Stress relaxation and/or slower reaction during the dark periods are the likely causes for the lower coating stress. It was advantageous to introduce dark periods early in the processing. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2784–2793, 2002
Resistance‐based switching humidity property of crosslinked acrylic acid–acrylamide copolymers and their ionization effect against the critical humidity
Authors: Liu Chong‐Jin
Published: August 2002

The resistance‐based switching humidity property of crosslinked acrylic acid–acrylamide copolymers was measured with an LCZ meter, and their ionic mobilities, which varied with humidity, were measured by the polar‐inversion method. Their conduction mechanism was discussed, and it was found that the ionization effect of some binding ions against a critical humidity takes place in switchable humidity‐sensitive materials. The effect is that some binding ions in materials turn into free ions when a given ambient humidity, called a critical humidity, is reached. The avalanching‐conduct electricity then occurs in materials. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1057– 1060, 2002
Microsphere synthesis by emulsion copolymerizations of styrene with poly(methacrylic acid) macromonomers
Authors: Ishizu Koji , Kim Sunwook , Ichimura Ayako
Published: August 2002

The polymer microspheres were synthesized by emulsion copolymerizations of styrene with vinyl benzyl terminated poly(methacrylic acid) (PMA) macromonomers in an aqueous ethanol solution. In these copolymerization systems, the macromonomer acted not only as a comonomer but also as a stabilizer. The particle diameters obtained from the water‐soluble initiator system showed smaller values than those obtained from the water‐insoluble initiator system. These polymer microspheres had a very narrow particle‐size distribution. The particle diameters depended strongly on the feed amount and molecular weight of PMA macromonomers, water fraction in the mixed solvent, and pH in the medium. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 900–905, 2002
The isothermal curing of a diepoxide‐cycloaliphatic diamine resin by temperature modulated differential scanning calorimetry
Authors: Montserrat S. , Martín J. G.
Published: August 2002

The thermal properties and the isothermal cure of an epoxy resin based on diglycidyl ether of bisphenol A (DGEBA) with a diamine based on 4,4′‐diamino‐3,3′‐dimethyldicyclohexylmethane (3DCM) were analyzed by differential scanning calorimetry (DSC) and temperature modulated DSC (TMDSC). The quasi‐isothermal TMDSC scans were performed at curing temperatures between 40 and 140°C for different periods of time, and the modulation conditions were amplitude of 0.5K and a period of 60 s. The heating rates used on the DSC scans were between 2.5 and 20 Kmin−1. The heat of curing measured nonisothermally increases when the heating rate decreases. An average value of 440 Jg−1 was estimated. The glass transition of the unreacted system measured by DSC was −40.4°C. The final glass transition temperature of the resin depends on the heating rate of cure and postcure conditions. Values between 143°C (measured by DSC) and 154°C (measured on the total heat flow by TMDSC) were obtained after isothermal curing and postcure at 10 and 1 Kmin−1, respectively. The vitrification was analyzed by the modulus of the complex heat capacity |C|, which decay gives the interval and the time of vitrification. These properties were used to build the time–temperature–transformation cure diagram. The intensity of the vitrification was measured by the change in |C|, which decreases quasi‐linearly with the curing temperature. The phase angle of the heat flow shows a peak in the vitrification region, which agrees with the vitrification time determined by |C|. The chemical kinetics may be fitted to a simplified autocatalytic model [f(α) = αm(1 − α)n, Sesták‐Berggren model] with an apparent activation energy of 58 kJmol−1. The analysis of the diffusion controlled step is studied using a mobility factor determined from the normalised variation of |C| during the vitrification. The simulated overall reaction rate, which is obtained from the product of the chemical kinetics and the mobility factor, agrees with the experimental reaction rate. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1263–1276, 2002
Physical properties of silk fibroin/chitosan blend films
Authors: Kweon Haeyong , Ha Hyun Chul , Um In Chul , Park Young Hwan
Published: August 2002

Silk fibroin/chitosan blend films were examined through IR spectroscopy to determine the conformational changes of silk fibroin. The effects of the fibroin/chitosan blend ratios (chitosan content) on the physical and mechanical properties were investigated to discover the feasibility of using these films as biomedical materials such as artificial skin and wound dressing. The mechanical properties of the blend films containing 10–40% chitosan were found to be excellent. The tensile strength, breaking elongation, and Young's modulus were affected by the chitosan contents of the blend films, which were also related to the density and degree of swelling. The coefficient of water vapor permeability of the blend films increased linearly with the chitosan content, and the values of 1000–2000 g m−2 day−1 were comparable to those of commercial wound dressings. Silk fibroin/chitosan blend films had good oxygen and water vapor permeabilities, making them useful as biomaterials. In particular, the blend film containing 40–50% chitosan showed very high oxygen permeability. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 928–934, 2001
Phase morphologies and mechanical properties of high‐impact polystyrene (HIPS) and polycarbonate blends compatibilized with polystyrene and polyarylate block copolymer
Authors: Ohishi Hiroshi , Ikehara Takayuki , Nishi Toshio
Published: August 2002

Phasemorphology and mechanical properties of blends of high‐impact polystyrene (HIPS) and polycarbonate (PC) blends compatibilized with a polystyrene (PS) and polyarylate (PAr) (PS–PAr) block copolymer were investigated. Over a broad range of composition from 50/50 through 30/70, HIPS/PC blends formed cocontinuous structures induced by the flow during the extrusion or injection‐molding processes. These cocontinuous phases had heterogeneity between the parallel and perpendicular directions to the flow. The micromorphology in the parallel direction to the flow consisted of stringlike phases, which were highly elongated along the flow. Their longitudinal size was long enough to be longer than 180 μm, while their lateral size was shorter than 5 μm, whereas that in the perpendicular direction to the flow showed a cocontinuous phase with regular spacing due to interconnection or blanching among the stringlike phases. The PS–PAr block copolymer was found to successfully compatibilize the HIPS/PC blends. The lateral size of the stringlike phases could be controlled both by the amount of the PS–PAr block copolymer added and by the shear rate during the extrusion or injection‐molding process without changing their longitudinal size. The HIPS/PC blend compatibilized with 3 wt % of the PS–PAr block copolymer under an average shear rate of 675 s−1 showed a stringlike phase whose lateral size was reduced almost equal to the rubber particle size in HIPS. The tensile modulus and yield stress of the HIPS/PC blends could be explained by the addition rule of each component, while the elongation at break was almost equal to that of PC. These mechanical properties of the HIPS/PC blends can be explained by a parallel connection model independent of the HIPS and PC phases. On the other hand, the toughness factor of the HIPS/PC blends strongly depended on the lateral size of the stringlike phases and the rubber particle size in the HIPS. It was found that the size of the string phases and the rubber particle should be smaller than 1.0 μm to attain a reasonable energy absorbency by blending HIPS and PC. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2347–2360, 2001
Effect of hard segment and concentration of NaClO4 on poly(ethylene oxide)–urethane/NaClO4 complex
Authors: Yang Bing , Zeng Lai‐Xiang , Wang Lei , Tang Xiao‐Zhen , Tian Guo‐Hua , Zhang Bin
Published: August 2002

Solid poly(ethylene oxide)–urethane electrolytes were prepared from blends of polyurethane and NaClO4. The samples were characterized by FTIR, DSC, atomic force microscopy, and complex impedance analysis. The effect of the concentration of NaClO4 on the poly(ethylene oxide)–urethane/NaClO4 complex were studied. The results showed that the concentration of NaClO4 had an important effect on the ion–polymer interaction, ion–ion interaction, glass‐transition temperature, morphologic structure, and ionic conductivity of the complex. We also prepared a model compound of hard segments and found that the conductivity of the complex decreased when the model compound was blended into the complex. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2502–2510, 2001
Polymerization of chlorofluorocarbon‐22 and acetonitrile
Authors: Shi Gaoquan , Chen Fengen , Wu Sanxie , Zhu Yongfa , Hong Xiaoying , Hou Wenhua , Ming Liang
Published: August 2002

Chlorofluorocarbon‐22 (HCClF2) gas can react with acetonitrile to form a halogen‐free carbon‐based polymer when solid potassium hydroxide particles are present. The reaction can be carried out under normal pressure and at room temperature. The polymer is powdery and amorphous. The structure of the polymer has been studied by elemental analysis, Fourier transform IR, Raman, and mass spectroscopies. The results demonstrate that the polymer has a carbonic backbone. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 116–120, 2001
Influence of rubber composition on migration behaviors of antiozonants in carbon black‐filled rubber vulcanizates composed of NR, SBR, and BR
Authors: Choi Sung‐Seen
Published: August 2002

Migration behaviors of antiozonants in carbon black‐filled rubber vulcanizates with different rubber compositions of natural rubber (NR), styrene–butadiene rubber (SBR), and butadiene rubber (BR) were studied at constant temperatures of 40–100°C and outdoors. Three single rubber‐based vulcanizates, three biblends, and three triblends were used. N‐Phenyl‐N′‐isopropyl‐p‐phenylenediamine (IPPD) and N‐phenyl‐N′‐(1,3‐dimethylbutyl)‐p‐phenylenediamine (HPPD) were employed as antiozonants. Migration rates of the antiozonants became faster with increasing the temperature. The order of the migration rates in the single rubber‐based vulcanizates was BR > NR > SBR. The migration rates in the vulcanizates containing SBR, on the whole, increased with decreasing the SBR content, while those in the vulcanizates containing BR decreased with decreasing the BR content. Difference in the migration behaviors of the antiozonants depending on the rubber composition was explained both by the intermolecular interactions of the antiozonants with the matrix and by interface formed between dissimilar rubbers in the blends. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 237–242, 2001
Carbon‐13 nuclear magnetic resonance investigation of styrene–α‐methylstyrene copolymers
Authors: Nogueira Regina F. , Tavares Maria Inês B.
Published: August 2002

A copolymer based on α‐methylstyrene (AMS) was investigated by nuclear magnetic resonance (NMR). The styrene‐co‐α‐methylstyrene (SAMS) was analyzed by solution and solid‐state NMR techniques. Three copolymers of SAMS with different compositions presented a particular behavior. The solution results showed the copolymer microstructure and the AMS content. The carbon‐13 spectra of SAMS C indicated that the AMS CH3 signal was detected at three distinct chemical shifts, because of the different comonomer‐sequences distribution. The proton spin–lattice relaxation time in the rotating frame (Tρ) parameter was chosen because it permits the evaluation of changes in the molecular mobility. The values of Tρ found for the copolymers confirmed the random distribution in the samples. The copolymer with a low quantity of AMS (1.7%), when analyzed by this relaxation parameter, showed lower values that were interpreted as an antiplasticization effect. The SAMS copolymer with a higher AMS quantity showed a plasticization effect. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 261–266, 2001
Effect of self‐nucleation on the crystallization of segmented copolymer poly(ether ester)
Authors: Gu Qun , Wu Liheng , Wu Dacheng , Shen Deyan
Published: August 2002

The effect of self‐nucleation on the nonisothermal and isothermal crystallization behaviors of the segmented copolymer poly(ether ester), based on poly(ethylene glycol) as the soft segment and poly(ethylene terephthalate) as the hard segment was investigated by means of differential scanning calorimetry (DSC) and depolarization polarized light (DPL) techniques, respectively. The results demonstrated that self‐nucleation could enhance the crystallization rate in both cases. The experimental conditions of the self‐nucleation procedure studied by DSC were discussed in detail. The isothermal crystallization was analyzed by the Avrami equation, and the Avrami parameters were dependent on the melting temperature. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 498–504, 2001
Synthesis and thermal properties of poly(urethane‐imide)
Authors: Jiang Bibiao , Hao Jianjun , Wang Wenyun , Jiang Luxia , Cai Xinxian
Published: August 2002

The synthesis and thermal properties of thermoplastic poly(urethane‐imide) (PUI) resins were studied. Model reaction studies on the reactions of 4,4′‐diphenylcarbamatodiphenylmethane and 4,4′‐diisocyanatodiphenylmethane with phthalic anhydride were performed. We found that the reaction of anhydrides with urethane groups could take place under certain reaction conditions. According to the model reaction studies, N‐2‐methyl‐pyrrolidone was employed as a solvent, and no catalyst was used in the polymerization. To restrain the side reaction of anhydrides with urethane groups, we adopted a two‐step chain‐extending procedure in a chain‐extending reaction. The inherent viscosity of PUI was 0.83–0.99 dL/g. The prepared polymers not only exhibited improved solubility in organic solvents but also formed flexible films. Thermogravimetric analysis showed that PUI exhibited a two‐step thermal weight‐loss pattern. The first step of the thermal degradation of PUI was attributed to the thermooxidizing cleavage of weak and labile linkage, such as urethane groups, isopropylidene, and methylene, except for imide rings. The polymer inherent viscosity decreased sharply during the first step of thermal degradation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 773–781, 2001