bluuebunny/crossref_metadata_2025_split huggingface dataset:
Morphology and thermal behavior of MCPA6/SAN blends prepared by anionic ring‐opening polymerization of ϵ‐caprolactam
Authors: Hou Lianlong , Yang Guisheng 
Published: January 2006

AbstractIn this article, a series of blends of monomer casting polyamide 6 and styrene‐co‐acrylonitrile (MCPA6/SAN) were prepared by in situ anionic ring‐opening polymerization of ϵ‐caprolactam. Their morphology and thermal behaviors were investigated by means of scanning electron microscope, differential scanning calorimeter, and wide‐angle X‐ray diffraction (WAXD), respectively. The SAN phase had much finer domain in MCPA6/SAN than that in the PA6/SAN blends prepared by melt blending of PA6 and SAN. All the melting and crystallization parameters of MCPA6/SAN blends decreased gradually with the increase of SAN content, while the melting temperature was almost unchanged. These results were due to the hydrolysis reaction of SAN that occurred during the anionic polymerization of ϵ‐caprolactam. In addition, WAXD results showed that only α crystal forms existed in the MCPA6/SAN blends. In addition, the mechanical property of MCPA6 was improved obviously by incorporating a certain amount of SAN. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1357–1363, 2006
Properties and preparation of compatibilized nylon 6 nanocomposites/ABS blends using functionalized metallocene polyolefin elastomer. I. Impact properties
Authors: Lai S.‐M. , Liao Y.‐C. , Chen T.‐W. 
Published: January 2006

AbstractThe impact behaviors of nanoclay‐filled nylon 6 (nano‐nylon 6) blended with poly(acrylonitrile–butadiene–styrene) terpolymers (ABS) prepared through a twin screw mixing process were investigated here using metallocene polyethylene grafted maleic anhydride (POE‐g‐MA) as a compatibilizer to enhance the interface interaction. No clear effect of compatibilizer on the dispersion of clay and crystalline structure of nano‐nylon 6 has been observed. In view of morphology and rheological behaviors, the effect of compatibilizer on the mechanical properties could be elucidated. It is found that impact strength increases with the addition of compatibilizer at various ABS compositions. Similar effects are also observed with decreasing test temperature at the nano‐nylon 6/ABS blend composition of 80/20. As for thermal properties, the heat distortion temperature shows a marginal decrease in the nano‐nylon 6/ABS blends. Rheological behavior indicates that increased viscosity is found for the investigated compatibilized systems. Through morphology observations, the etched ABS particle sizes tend to decrease with the addition of compatibilizer for the blends, but are larger with higher contents of ABS concentrations. Those observations account for impact behaviors of the investigated blends. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1364–1371, 2006
Effect of elastomer type and functionality on the behavior of toughened polyamide nanocomposites
Authors: Kelnar I. , Kotek J. , Kaprálková L. , Hromádková J. , Kratochvíl J. 
Published: January 2006

AbstractThe only shortcoming of PA6‐based nanocomposites is low toughness, which is the same as that of the matrix. This work is focused on optimization of toughening these nanocomposites by introduction of small amounts of finely dispersed elastomers. A comparison of reactively compatibilized and analogous nonreactive elastomer‐containing nanocomposites indicates the best‐balanced mechanical behavior for polar nonreactive elastomers such as NBR and E‐MA. This is explained by a significant compatibilizing effect of clay. Besides the elastomer particle size and its properties, the clay localization and its degree of ordering in the interfacial region also significantly influenced mechanical properties of the system. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1571–1576, 2006
Preparation and characterization of EVA–sisal fiber composites
Authors: Malunka M. E. , Luyt A. S. , Krump H. 
Published: January 2006

AbstractIn this work, composites of an EVA polymer matrix and short sisal fiber were characterized. The physical‐morphological as well as chemical interactions between EVA and sisal were investigated. When the samples were prepared in the presence of dicumyl peroxide, the results suggest that crosslinking of EVA as well as grafting between EVA and the sisal fibers took place. Morphological changes were studied by scanning electron microscopy (SEM). Results from Hg‐porosimetry, SEM, Fourier transform infrared spectroscopy, surface free energy, and gel content strongly indicate grafting of EVA onto sisal under the composite preparation conditions, even in the absence of peroxide. The grafting mechanism could not be confirmed from solid‐state 13C NMR analysis. The grafting had an impact on the thermal and mechanical properties of the composites, as determined by differential scanning calorimetry and tensile testing. Thermogravimetric analysis results show that the composites are more stable than both EVA and sisal fiber alone. The composite stability, however, decreases with increasing fiber content. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1607–1617, 2006
A study of the synthesis, kinetics, and characterization of reactive graft copolymers of poly(vinyl imidazole) and cellulose for use as supports in enzyme immobilization and metal ion uptake
Authors: Chauhan Ghanshyam S. , Singh Baljit , Chauhan Sandeep , Dhiman Surya K. , Kumar Dinesh 
Published: January 2006

AbstractIn continuation to our earlier work to use bioresource for developing alternate materials for use at the interface of biotechnology and polymer science, we have utilized pine needles as a renewable stock of cellulose to synthesize graft copolymers of vinyl imidazole. Kinetics of N‐VIm by simultaneous γ‐irradiation method has been investigated as a function of total dose, monomer concentration, and amount of water. Effect of water–methanol solvent composition on graft yields and polymerization kinetics has also been studied at the optimum grafting conditions of the total dose and monomer concentration. Effect of some additives such as ZnCl2, Mohr salt, tetramethylethylene diamine, potassium persulfate, ammonium persulfate as grafting accelerators and promoters has also been studied. Graft copolymers have been characterized by elemental analysis, FTIR, and swelling studies. The graft copolymers have been used as supports for metal ions sorption, enzyme immobilization, and as potential biomimicking catalysts. Sorption behavior of Fe2+ ions and Cu2+ ions and the immobilization of bovine serum albumin and protease as a function of graft yield has been reported. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1522–1530, 2006
Coagulation and sedimentation of bacteria using a highly biodegradable polymeric coagulant
Authors: Kawabata Nariyoshi , Fuse Tomoaki 
Published: January 2006

AbstractCopolymer of acrylamide with N‐benzyl‐4‐vinylpyridinium chloride (PAAM‐co‐BVP) produced coagulation and sedimentation of Escherichia coli, Bacillus subtillus, Pseudomonas aeruginosa, and Staphylococcus aureus. Addition of more than 50 mg L−1 of PAAM‐co‐BVP produced bacterial flocks that precipitated at a rate of around 200 cm h−1. Supernatant population reduced in the range 1/30,000–1/25,000,000. Reduction of supernatant population was most effective when about 200 mg L−1 of PAAM‐co‐BVP was added. PAAM‐co‐BVP was highly biodegradable and the half‐life estimated was 2.4 days when treated with activated sludge. The ratio of biochemical oxygen demand for 5 days (BOD5) to total organic carbon (TOC) was 0.607. Coagulation and sedimentation of bacteria using PAAM‐co‐BVP is expected to improve the water disinfection processes by saving chlorine and other hazardous chemical fungicides and by reducing the formation of trihalomethanes and other toxic chemical materials. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1618–1623, 2006
Poly(ε‐caprolactone)‐grafted acetylated anhydroglucose oligomer by ring‐opening polymerization—Synthesis and characterization
Authors: Gädda Thomas , Kylmä Janne , Tuominen Jukka , Mikkonen Hannu , Laine Aki , Peltonen Soili , Seppälä Jukka 
Published: January 2006

AbstractA novel acetylated anhydroglucose oligomer (AGU‐oligomer), prepared by acid catalyzed transglycosidation of potato starch triacetate and ethylene glycol, was used as a multifunctional coinitiator for the ring‐opening polymerization of ε‐caprolactone (ε‐CL). The polymers were synthesized using different weight ratios of the starting materials and were characterized by NMR, SEC, and MALLS. The results confirmed the expected P(AGU/CL) polymer structure, namely a ‘comb‐like’ graft‐copolymer having the AGU oligomer as backbone with PCL grafts of variable chain lengths (LCL = 4–21). Thermal and mechanical properties of graft‐copolymers with different ε‐CL block lengths were examined. By changing the graft length, crystallinity was controlled and amorphous polymers were obtained with AGU‐oligomer contents higher than 50 wt %. The tensile properties varied with the composition and a copolymer having 40 wt % of AGU‐oligomer behaved like soft elastomer, showing high elongation at break. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1633–1641, 2006
Comparison of propylene/ethylene copolymers prepared with different catalysts
Authors: Stephens C. H. , Poon B. C. , Ansems P. , Chum S. P. , Hiltner A. , Baer E. 
Published: January 2006

AbstractThis study compared a series of experimental propylene/ethylene copolymers synthesized by a transition metal‐based, postmetallocene catalyst (xP/E) with homogeneous propylene/ethylene copolymers synthesized by conventional metallocene catalysts (mP/E). The properties varied from thermoplastic to elastomeric over the broad composition range examined. Copolymers with up to 30 mol % ethylene were characterized by thermal analysis, density, atomic force microscopy, and stress–strain behavior. The xP/Es exhibited noticeably lower crystallinity than mP/Es for the same comonomer content. Correspondingly, an xP/E exhibited a lower melting point, lower glass transition temperature, lower modulus, and lower yield stress than an mP/E of the same comonomer content. The difference was magnified as the comonomer content increased. Homogeneous mP/Es exhibited space‐filling spherulites with sharp boundaries and uniform lamellar texture. Increasing comonomer content served to decrease spherulite size until spherulitic entities were no longer discernable. In contrast, axialites, rather than spherulites, described the irregular morphological entities observed in xP/Es. The lamellar texture was heterogeneous in terms of lamellar density and organization. At higher comonomer content, embryonic axialites were dispersed among individual randomly arrayed lamellae. These features were characteristic of a copolymer with heterogeneous chain composition. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1651–1658, 2006
Thermogravimetric analysis of agricultural residues: Oxygen effect and environmental impact
Authors: Šimkovic Ivan , Csomorová Katarína 
Published: January 2006

AbstractAgricultural by‐products (wheat straw, WS; sugar beet, SB; corn cobs, CC; rape extracted meal, REM; soya bean hulls, SBH; bagasse, B; almond shells, AS; and olive stones; OS) were analyzed by dynamic and isothermal thermogravimetry (TG) in inert and oxidative environment. The goal was to evaluate the effect of oxygen presence on thermolysis and to compare the environmental impact of individual samples. In the inert environment at 250°C, the sequence according to decreasing residue amount under dynamic conditions is B (95%) > CC > WS > SBH = AS > OS > REM > SB (80%). This represents the decreasing role of hemicellulose and pectin components on thermal stability of individual samples. At 500°C the order changed to: REM (35%) > OS > AS > SB > SBH > B > CC > WS (24%). The TG/derivative thermogravimetry (DTG) values determined in air atmosphere could not be used for determination of individual macromolecular components due to overlapping of DTG maxima. For most of the studied samples, the measured residues under dynamic conditions were greater in the inert than in the oxidative environment. According to the thermooxidation maxima, the maximal difference of measured residues on dynamic TG curves run in nitrogen and oxygen environments in the order of decreasing thermooxidation resistance: B (32%; 325°C) > AS (29%; 450°C) > OS (23%; 450°C) > SBH (20%; 475°C) > WS (21%; 300°C) > SB (13%; 325°C) > REM (15%; 500°C). This is due to the largest protein content of REM (29%) as well as pectin, hemicellulose, and lignin composition of samples. Under isothermal conditions the rate constants were determined by linear regression method and are considered as initial rate constants of material degradation. For inert conditions, the smallest rate constants and biggest activation energy (E*) were determined on CC. The values of the rate constants increase in the following order CC < WS < SBH < B < OS < AS < SB < REM. In general it can be concluded that the rate constant values measured in oxygen are greater than analogical values measured in nitrogen. The determined E* values in oxygen were greater for AS, WS, B, SBH, and OS than the analogical values determined in nitrogen. They were decreasing in the following order: AS > WS > B > SBH > OS. On CC, SB and REM, E* values were lower in comparison with the E* calculated for inert conditions. We assume that when the E* value decreased in the presence of oxygen and when simultaneously smaller residue was formed under dynamic conditions, then the material is more unsuitable as a fuel from environmental point of view. It is because more oxygen was consumed and more material was gasified than on samples with closer values in both environments. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1318–1322, 2006
A microindentation study of polyethylene composites produced by hot compaction
Authors: Orench I. Puente , Calleja F. J. Balta , Hine P. J. , Ward I. M. 
Published: January 2006

AbstractMicroindentation measurements are reported on a range of single polymer polyethylene (PE) composites, which are produced by hot compaction of high modulus PE fibers. It is possible to measure two hardness values, parallel and perpendicular to the fiber direction respectively, from which the microindentation anisotropy is defined. The hardness values relate to the instantaneous elastic recovery of the fibers, and the results show that the microindentation measurement is deforming a material volume below the surface of the sheets comparable to the dimensions of the fibers. It appears that the microindentation anisotropy approaches a limiting value with increasing fiber orientation, i.e., as the Young's modulus of the fibers increases. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1659–1663, 2006
Study on the electrodriven action of gelatin hydrogel in silicone oil
Authors: Liu Genqi , Zhao Xiaopeng 
Published: January 2006

AbstractAction of gelatin hydrogel crosslinked with glutaraldehyde under dc electric field of high voltage was studied. The experimental results show that the hydrogel can be driven by dc electric field of high voltage in the medium of silicone oil, and the action of the hydrogel is composed of rotation and translation. There is a low critical applied voltage of 0.5 kV, below which the action of the hydrogel may not be observed. The motion velocity and angle of the rotation of gelatin hydrogel are influenced by the electric field intensity. Because silicone oil is very stable and hard to electrolyze in electric field, gas formation associated with the electrolysis of water, which is inevitable and disadvantageous in conventional system of electric‐stimulus‐response hydrogel, would not happen. Our work has provided a novel kind of electrodriven methods for hydrogels. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1664–1667, 2006
Two invaders achieve higher densities in reserves
Authors: Klinger Terrie , Padilla Dianna K. , Britton‐Simmons Kevin 
Published: January 2006

Abstract
Invasive species threaten marine biodiversity on a global scale.
To test whether marine reserves provide resistance to invading species, the abundance of two conspicuous invaders, a seaweed and an oyster, were measured inside marine reserves and in comparable areas outside reserves in north‐western Washington State.
Densities of both invaders were significantly higher in marine reserves than in comparable unprotected areas outside reserves. Although the causal mechanisms have not yet been identified, differential rates of human harvest do not appear to be responsible for the patterns observed.
It is provisionally suggested that physical or biological aspects of the reserves themselves may directly or indirectly facilitate biological invasion.
Copyright © 2006 John Wiley & Sons, Ltd.
The impact of glycosylation on HLA–DR1–restricted T cell recognition of type II collagen in a mouse model
Authors: von Delwig Alexei , Altmann Daniel M. , Isaacs John D. , Harding Clifford V. , Holmdahl Rikard , McKie Norman , Robinson John H. 
Published: January 2006

AbstractObjectiveType II collagen (CII) is a candidate autoantigen implicated in the pathogenesis of rheumatoid arthritis (RA). Posttranslational glycosylation of CII could alter intracellular antigen processing, leading to the development of autoimmune T cell responses. To address this possibility, we studied the intracellular processing of CII for presentation of the arthritogenic glycosylated epitope CII259–273 to CD4 T cells in macrophages from HLA–DR1–transgenic mice.MethodsHLA–DR1–transgenic mice were generated on a class II major histocompatibility complex–deficient background, and T cell hybridomas specific for the glycosylated and nonglycosylated epitope CII259–273 were developed. Subcellular fractionation of macrophages was used to localize CII degradation to particular compartments and to identify the catalytic subtype of proteinases involved.ResultsWe showed that the glycosylated CII259–273 epitope required more extensive processing than did the nonglycosylated form of the same epitope. Dense fractions containing lysosomes were primarily engaged in the processing of CII for antigen presentation, since these compartments contained 1) enzyme activity that generated antigenic CII fragments bearing the arthritogenic glycosylated epitope, 2) the antigenic CII fragments themselves, 3) CII peptide–receptive HLA–DR1 molecules, and 4) peptide/HLA–DR1 complexes that could directly activate T cell hybridomas. Degradation of CII by dense fractions occurred optimally at pH 4.5 and was abrogated by inhibitors of serine and cysteine proteinases.ConclusionProcessing of the arthritogenic glycosylated CII259–273 epitope, which is implicated in the induction of autoimmune arthritis, is more stringently regulated than is processing of the nonglycosylated form of the same epitope. Mechanisms of intracellular processing of the glycosylated epitope may constitute novel therapeutic targets for the treatment of RA.
Prevention of spontaneous arthritis by inhibiting homeostatic expansion of autoreactive CD4+ T cells in the K/BxN mouse model
Authors: Jang Eunkyeong , Kim Hong Ro , Cho Sin Hye , Paik Doo‐Jin , Kim Jung Mogg , Lee Sang‐Koo , Youn Jeehee 
Published: January 2006

AbstractObjectiveK/BxN‐transgenic mice are a model of autoimmune arthritis, similar to rheumatoid arthritis. This study was undertaken to determine whether inhibition of lymphopenia‐provoked homeostatic expansion can prevent spontaneous development of disease in the K/BxN model.MethodsTo inhibit homeostatic expansion of autoreactive T cells, K/BxN mice with disease in the preclinical stage were adoptively transferred with CD4+ T cells purified from nontransgenic BxN or Thy1.1+ BxN mice. To observe the profile of proliferation of CD4+ T cells derived from the hosts, carboxyfluorescein diacetate succinimidyl ester–labeled autologous CD4+ T cells were cotransferred to K/BxN mice together with BxN CD4+ T cells. Disease onset and progression were scored, and the dynamics and phenotypes of recipient CD4+ T cells were determined by flow cytometry, before and after cell infusion.ResultsDuring the preclinical phase of disease, K/BxN mice exhibited CD4+ T lymphopenia, which was followed by a compensatory expansion of these cells during the early clinical phase. The majority of CD4+ T cells acquired a memory phenotype (CD44high,CD62Llow,CD25−), which is a hallmark of homeostatically expanding cells. Importantly, K/BxN mice subjected to syngeneic T cell transfer did not develop symptoms of arthritis and also possessed fewer transgenic T cell receptor–encoded Vβ6+,CD4+ T cells. This effect was associated with decreased proliferation of recipient‐derived CD4+ T cells but not with the function of CD25+ T regulatory cells present in donor cells.ConclusionThese results provide the first evidence that lymphopenia‐associated homeostatic proliferation of autoreactive CD4+ T cells potentiates autoimmune arthritis, and that inhibition of this process protects mice from the development of this pathologic condition.
Treatment for rheumatoid arthritis and the risk of hospitalization for pneumonia: Associations with prednisone, disease‐modifying antirheumatic drugs, and anti–tumor necrosis factor therapy
Authors: Wolfe Frederick , Caplan Liron , Michaud Kaleb 
Published: January 2006

AbstractObjectivePneumonia is a major cause of mortality and morbidity in rheumatoid arthritis (RA). This study was undertaken to determine the rate and predictors of hospitalization for pneumonia and the extent to which specific RA treatments increase pneumonia risk.MethodsRA patients (n = 16,788) were assessed semiannually for 3.5 years. Pneumonia was confirmed by medical records or detailed patient interview. Covariates included RA severity measures, diabetes, pulmonary disease, and myocardial infarction. Cox proportional hazards regression was used to determine the multivariable risk associated with RA treatments.ResultsAfter adjustment for covariates, prednisone use increased the risk of pneumonia hospitalization (hazard ratio [HR] 1.7 [95% confidence interval 1.5–2.0]), including a dose‐related increase in risk (≤5mg/day HR 1.4 [95% confidence interval 1.1–1.6], >5–10 mg/day HR 2.1 [95% confidence interval 1.7–2.7], >10 mg/day HR 2.3 [95% confidence interval 1.6–3.2]). Leflunomide also increased the risk (HR 1.2 [95% confidence interval 1.0–1.5]). HRs for etanercept (0.8 [95% confidence interval 0.6–110]) and sulfasalazine (0.7 [95% confidence interval 0.5–1.0]) did not reflect an increased risk of pneumonia. HRs for infliximab, adalimumab, and methotrexate were not significantly different from zero.ConclusionThere is a dose‐related relationship between prednisone use and pneumonia risk in RA. No increase in risk was found for anti–tumor necrosis factor therapy or methotrexate. These data call into question the belief that low‐dose prednisone is safe. Because corticosteroid use is common in RA, the results of this study suggest that prednisone exposure may have important public health consequences.