bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structure and electrical properties of grafted polypropylene/graphite nanocomposites prepared by solution intercalation
Authors: Shen Jing‐Wei , Chen Xiao‐Mei , Huang Wen‐Yi 
Published: March 2003

AbstractA novel process was developed to prepare electrically conducting maleic anhydride grafted polypropylene (gPP)/expanded graphite (EG) nanocomposites by solution intercalation. The conducting percolation threshold at room temperature (Φc) of the nanocomposites was 0.67 vol %, much lower than that of the conventional conducting composites prepared by melt mixing (Φc = 2.96 vol %). When the EG content was 3.90 vol %, the electrical conductivity (σ) of the former reached 2.49 × 10−3 S/cm, whereas the σ of the latter was only 6.85 × 10−9 S/cm. The TEM, SEM, and optical microscopy observations confirmed that the significant decrease of Φc and the striking increase of σ might be attributable to the formation of an EG/gPP conducting multiple network in the nanocomposites, involving the network composed of particles with a large surface‐to‐volume ratio and several hundred micrometers in size, and the networks composed of the boards or sheets of graphite with high width‐to‐thickness ratio and particles of fine microscale or nanoscale sizes. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1864–1869, 2003
Thermoplastic elastomeric blend of nitrile rubber and poly(styrene‐co‐acrylonitrile). I. Effect of mixing sequence and dynamic vulcanization on mechanical properties
Authors: Anandhan S. , De P. P. , De S. K. , Bhowmick Anil K. 
Published: March 2003

AbstractThe effects of dynamic vulcanization and blend ratios on mechanical properties and morphology of thermoplastic elastomeric (TPE) compositions, based on blends of nitrile rubber (NBR) and poly(styrene‐co‐acrylonitrile) (SAN), were studied. The TPE composition prepared by adding a rubber‐curatives masterbatch to softened SAN yields higher mechanical properties than that prepared by adding curatives to the softened plastic–rubber preblend. The blends having a higher rubber–plastic ratio (60 : 40 to 80 : 20) display thermoplastic elastomeric behavior, whereas those having a higher plastic–rubber ratio (50 : 50 to 90 : 10) display the behavior of impact‐resistant plastics. DSC studies revealed that NBR and SAN are thermodynamically immiscible. SEM studies of the thermoplastic elastomeric compositions show that SAN forms the matrix in which fine particles of NBR form the dispersed phase. It was further confirmed by dynamic mechanical thermal analysis. Dynamic vulcanization causes a decrease in the size of dispersed particles and improvement in mechanical properties. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1976–1987, 2003
Hybrid sol–gel membranes of polyacrylonitrile–tetraethoxysilane composites for gas permselectivity
Authors: Iwata Minoru , Adachi Takeharu , Tomidokoro Miwa , Ohta Michiyoshi , Kobayashi Takaomi 
Published: March 2003

AbstractSol–gel reaction of tetraethoxysilane (TEOS) with fumed silica–polyacrylonitrile (PAN) membrane was carried out to prepare hybrid gas permeable membranes for oxygen and nitrogen separation. Various amounts of fumed silica microparticles with a few μm diameters were compounded in PAN–dimethylsulfoxide (DMSO) solution. After casting of the viscous compound solution on a flat sheet with 100 μm thickness, DMSO was evacuated under vacuum at 80°C. Then, the silica–PAN composite membranes were treated with TEOS for 1 day at 40°C in methanol. Air permeation was examined and compared in silica–PAN composite membranes with and without TEOS treatment. The latter hybrid membranes showed selective oxygen permeability, which depended on amounts of fumed silica in the membrane. The TEOS hybrid PAN membranes have a high ability of oxygen permselectivity for O2/N2 gas mixture with α(O2/N2) = 13–17, when the silica content was in the range of 13–20 wt %. This is attributed to siloxane network formation in hybrid silica–PAN composite membranes. Favorable siloxane network formation resulted in high oxygen permeability of the hybrid composite membranes. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1752–1759, 2003
Mechanical properties of high‐density polyethylene/scrap rubber powder composites modified with ethylene–propylene–diene terpolymer, dicumyl peroxide, and silicone oil
Authors: Li Yan , Zhang Yong , Zhang Yinxi 
Published: March 2003

AbstractThe effect of ethylene–propylene–diene terpolymer (EPDM), dicumyl peroxide (DCP), and dimethyl silicone oil on the mechanical properties of high‐density polyethylene (HDPE) composites filled with 60 mesh cryogenically scrap rubber powder (SRP) was studied. The addition of 10 wt % EPDM, 0.2 wt % DCP, and 4 wt % dimethyl silicone oil significantly increased both the impact strength and elongation at break of the HDPE/SRP composites. After the modification, the impact strength increased by 160%, and the elongation at break increased by 150% for the composites containing 40 wt % SRP. The impact load–time curves showed that the increase of impact energy for the modified composites was attributed to the increase of the maximum force at yield point and the ductile deformation after yielding. The rheological behavior, dynamic mechanical properties, and morphology observation suggested that an enhanced adhesion between SRP and polymer matrix formed in the modified HDPE/SRP composites. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2020–2027, 2003
Precipitation polymerization of acrylic acid in compressed carbon dioxide–cosolvent systems
Authors: Xu Qun , Han Buxing , Yan Haike 
Published: March 2003

AbstractPrecipitation polymerizations of acrylic acid (AA) in compressed carbon dioxide (65 bar) with different cosolvents, acetic acid, ethanol, and tetrahydrofuran, were studied. Analyses by viscosity measurement and differential scanning calorimetry indicate that the cosolvents have a pronounced effect on the properties of the product. Scanning electron microscopy shows that the products progress from microparticles to bicontinuous networks to fibers with the change of cosolvents and reaction conditions. Measurement of the volume expansion (ΔV%) of the liquid phase containing different cosolvents indicates that the miscibility of compressed CO2 with the liquid phase is dependent on the cosolvent. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1876–1880, 2003
Mechanical behavior of nylon composites containing talc and kaolin
Authors: Unal H. , Fındık F. , Mimaroglu A. 
Published: March 2003

AbstractParticulate reinforced thermoplastic composites are designed to improve the properties and to lower the overall cost of engineering plastics. In this study, the influence of adding talc and kaolin fillers on the mechanical properties of nylon 6 was investigated. Fillers, either singly or mixed by various weight ratios between 10 and 30 wt %, were added to nylon 6. Test samples of the composite material were prepared by the injection‐molding process. Uniaxial tensile and Izod impact tests were carried out. Tensile strength, elongation at break, modulus of elasticity, and impact energy were obtained. The results showed that the tensile strength and modulus of elasticity of nylon 6 composite increased with the increase in filler ratio, whereas the impact strength and maximum elongation decreased with the increase in filler ratio. The optimal nylon composite was determined with the addition of a 10 to 15 wt % filler ratio. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1694–1697, 2003
Phase behavior of side‐chain liquid‐crystalline elastomers and their precursors containing para‐nitro azobenzene
Authors: Li Min , Hu Zhijun , Chen Gang , Chen Xinfang 
Published: March 2003

AbstractSide‐chain liquid‐crystalline copolymethacrylates (PMm's), containing para‐nitro azobenzene as the mesogenic group and 2‐hydroxylethyl methacrylate (HEMA) as a comonomer, were synthesized by radical polymerization, and their corresponding liquid‐crystalline elastomers (LCEm's) were prepared through chemical crosslinking. All of the polymers (PMm's) and the elastomers studied showed enantiotropic smectic A phases; the clearing temperature (Ti) of the PMm polymers decreased with increasing amount of HEMA, and the Ti of the corresponding LCEm's decreased compared to that of their precursors. Small‐angle X‐ray scattering studies on the copolymers quenched from their liquid‐crystalline phases indicated that the characteristic distance increased with increasing amorphous component content and thus, the amorphous components were in between the smectic layers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2275–2279, 2003
Thermally induced phase separation in poly(lactic acid)/dialkyl phthalate systems
Authors: Lee Jae Sung , Lee Hwan Kwang , Kim Je Young , Hyon Suong‐Hyu , Kim Sung Chul 
Published: March 2003

AbstractThermally induced phase separation in poly(lactic acid)/dialkyl phthalate systems was investigated. Poly(DL‐lactic acid) (PDLLA) and poly(L‐lactic acid) (PLLA) with different molecular weights were used. A series of dialkyl phthalates, with different numbers of carbon atoms in the alkyl chain, were employed as solvents to control the interaction between polymer and solvent. The liquid–liquid phase‐separation temperature of the poly(lactic acid) solutions decreased systematically with a shorter alkyl chain in the phthalate. Based on the interaction between polymer and solvent and the molecular weight of polymer influencing liquid–liquid phase‐separation temperature significantly but crystallization temperature only slightly, proper thermal conditions were employed to investigate competitive phase separation and crystallization in PLLA solutions. Factors that can influence the final morphology of PLLA solutions were examined. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2224–2232, 2003
A nanocomposite of poly(N‐vinylcarbazole) with nanodimensional alumina
Authors: Maity Arjun , Biswas Mukul 
Published: March 2003

AbstractA nanocomposite of poly(N‐vinylcarbazole) (PNVC) and Al2O3 was prepared by precipitation of a preformed PNVC in a tetrahydrofuran solution onto an aqueous suspension of nanodimensional Al2O3. Prolonged extraction of a PNVC–Al2O3 composite by benzene failed to extract the loaded PNVC from the Al2O3, as shown by Fourier transform infrared studies. Scanning electron microscopy analyses revealed distinct morphological features of the composite, and transmission electron microscopy analyses confirmed that the particle sizes were in the range of 120–240 nm. Thermogravimetric analyses demonstrated the enhanced stability of the nanocomposite relative to the base polymer. Direct current conductivity of the PNVC–Al2O3 composites was found to be about 0.14 × 10−6 S/cm. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2233–2237, 2003
Toughness response of vinylester/epoxy‐based thermosets of interpenetrating network structure as a function of the epoxy resin formulation: Effects of the cyclohexylene linkage
Authors: Karger‐Kocsis J. , Gryshchuk O. , Jost N. 
Published: March 2003

AbstractVinylester/epoxy (VE/EP)‐based thermosets of interpenetrating network (IPN) structures were produced by using a VE resin (bismethacryloxy derivative of a bisphenol A–type EP resin) with aliphatic (Al‐EP) and cycloaliphatic (Cal‐EP) EP resins. Curing of the EP resins occurred either with an aliphatic (Al‐Am) or cycloaliphatic diamine compound (Cal‐Am). Dynamic mechanical thermal analysis (DMTA) and atomic force microscopy (AFM) suggested the presence of an interpenetrating network (IPN) in the resulting thermosets. Fracture toughness (Kc) and fracture energy (Gc) were used as the toughness characterization parameters of the linear elastic fracture mechanics. Unexpectedly high Kc and Gc data were found for the systems containing cyclohexylene units in the EP network, such as VE/Al‐EP+Cal‐Am and VE/Cal‐EP+Al‐Am. This was attributed to the beneficial effects of the conformational changes of the cyclohexylene linkages (chair/boat), which were closely analogous to those in some thermoplastic copolyesters. The failure mode of the VE/EP thermoset combinations was studied in scanning electron microscopy (SEM) and discussed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2124–2131, 2003
Characterization of unsaturated polyester and alkyd resins using one‐ and two‐dimensional NMR spectroscopy
Authors: Spyros A. 
Published: March 2003

AbstractOne‐ (1D) and two‐dimensional (2D) 1H‐ and 13C‐NMR spectroscopy was used to characterize polyester and alkyd resins used in the coatings industry. The wealth of chemical composition information of the 1H‐ and 13C‐NMR 1D spectra of the resins is revealed through 2D NMR experiments that spread chemical shifts in two dimensions, thus facilitating the peak assignment of the various components of the resins. It is shown that the types of polyols, acids, and vegetable oils used to modify the resins can be efficiently traced by NMR spectroscopic techniques. Information on the quantitative composition of the resins and especially the abundance of unsaturated fatty acid double bonds, which influences resin dryability and hardness, can be easily extracted from the 1H‐NMR spectra upon successful assignment. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1881–1888, 2003
Static and dynamic mechanical properties of modified bismaleimide and cyanate ester interpenetrating polymer networks
Authors: Fan Jing , Hu Xiao , Yue Chee Yoon 
Published: March 2003

AbstractInterpenetrating polymer networks (IPNs) based on different ratios of modified bismaleimide (BMI) resin [BMI/2,2′‐diallylbisphenol A (DBA)] and cyanate ester (CE) (b10) have been synthesized via prepolymerization followed by thermal curing. A systematic study of both static and dynamic mechanical properties of the cured BMI/DBA–CE IPN resin systems was conducted through flexural, impact testing, and dynamic mechanical analysis (DMA). The static mechanical investigation shows that the flexural strength, flexural strain at break, and impact strength of the cured BMI/DBA–CE IPN resin systems are relatively lower than that calculated by rule of mixture of two individuals: BMI/DBA and b10. However, the flexural moduli of the IPN resin systems have more consistent features compared to that calculated by rule of mixture. Single damping peaks are detected for the cured BMI/DBA–CE IPN resin systems, which suggests a substantial degree of interpenetration between two networks. The damping peaks of the cured BMI/DBA–CE IPN resin systems do tend to become broader with increasing concentration of BMI/DBA, whereas the intensity of damping peaks of the IPN resin systems decreases. The obtained results not only provide insight information about the characteristic structures of these BMI/DBA‐–CE IPN resin systems, but also give guidelines for their applications. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2000–2006, 2003
Remyelination by transplanted olfactory ensheathing cells
Authors: Franklin Robin J.M. 
Published: March 2003

AbstractThe olfactory ensheathing cells (OECs) of the peripheral olfactory system associate with the axons of the first cranial nerve. These axons are not myelinated by OECs because of their very small diameter. However, when OECs are transplanted into areas where they encounter larger‐diameter axons, such as in a model of primary demyelination, these cells assume a myelinating phenotype. Myelinating OECs very closely resemble myelinating Schwann cells by all criteria currently examined, including morphology, ultrastructure, biochemistry, and transcriptional regulation. Indeed, it is currently impossible to reliably distinguish myelinating OECs and myelinating Schwann cells that have been transplanted into experimental models of CNS demyelination. This article describes recent studies on the myelinating properties of transplanted OECs, focusing on their intrinsic myelinating potential and how this can be augmented by the presence of meningeal cells. The relative merits of OECs compared with Schwann cells when transplanted into astrocyte‐containing lesions in the CNS are discussed together with their potential role in transplanted‐mediated repair of demyelinating disease such as multiple sclerosis. Anat Rec (Part B: New Anat) 271BB:71–76, 2003. © 2003 Wiley‐Liss, Inc.
Olfactory ensheathing glia transplantation: A therapy to promote repair in the mammalian central nervous system
Authors: Santos‐Benito Fernando F. , Ramón‐Cueto Almudena 
Published: March 2003

AbstractA therapy to treat injuries to the central nervous system (CNS) is, to date, a major clinical challenge. The devastating functional consequences they cause in human patients have encouraged many scientists to search, in animal models, for a repair strategy that could, in the future, be applied to humans. However, although several experimental approaches have obtained some degree of success, very few have been translated into clinical trials. Traumatic and demyelinating lesions of the spinal cord have attracted several groups with the same aim: to find a way to promote axonal regeneration, remyelination, and functional recovery, by using a simple, safe, effective, and viable procedure. During the past decade, olfactory ensheathing glia (OEG) transplantation has emerged as a very promising experimental therapy to promote repair of spinal cords, after different types of injuries. Transplants of these cells promoted axonal regeneration and functional recovery after partial and complete spinal cord lesions. Moreover, olfactory ensheathing glia were able to form myelin sheaths around demyelinated axons. In this article, we review these recent advances and discuss to what extent olfactory ensheathing glia transplantation might have a future as a therapy for different spinal cord affections in humans. Anat Rec (Part B: New Anat) 271B:77–85, 2003. © 2003 Wiley‐Liss, Inc.
Asymptomatic avascular necrosis in patients with primary antiphospholipid syndrome in the absence of corticosteroid use: A prospective study by magnetic resonance imaging
Authors: Tektonidou Maria G. , Malagari Katerina , Vlachoyiannopoulos Panayiotis G. , Kelekis Dimitris A. , Moutsopoulos Haralampos M. 
Published: March 2003

AbstractObjectiveTo evaluate the prevalence of avascular necrosis (AVN), using magnetic resonance imaging (MRI), in patients with primary antiphospholipid syndrome (APS) and in patients with systemic lupus erythematosus (SLE), with or without anticardiolipin antibodies (aCL), who are asymptomatic for AVN and have not taken corticosteroids.MethodsSeventy‐nine subjects who were asymptomatic for AVN were evaluated by MRI of the femoral heads: 30 patients with primary APS who had never received corticosteroids, 19 SLE patients who had never received steroids (divided into 2 groups, aCL positive and aCL negative, in order to examine any association between AVN and aCL), and 30 healthy subjects who were age‐ and sex‐matched with patients with primary APS. Established MRI criteria were used for a diagnosis of AVN.ResultsAsymptomatic AVN was evident in 6 (20%) of 30 patients with primary APS: 3 of them (1 man, 2 women) had intermediate bilateral AVN, and 3 (all women) had early AVN (bilateral in 1 patient). Results of hip and pelvis radiography and dynamic scintigraphy were negative. Followup MRI 6 months later revealed no changes. At the time of the initial MRI examination, the mean (±SD) age of patients in whom AVN was identified was 31.2 ± 7.3 years, and that of patients without AVN was 42.4 ± 11.9 years (P = 0.036). Livedo reticularis occurred significantly more commonly in the group with AVN (P = 0.041). None of the healthy subjects and none of the patients with SLE demonstrated AVN on MRI.ConclusionAVN can be detected by MRI in 20% of patients with primary APS. Younger patients tend to develop AVN more frequently than do older patients, and the presence of livedo reticularis may identify individuals at risk for AVN. Clinicians should be aware of this possible clinical manifestation of primary APS, because early diagnosis can lead to early intervention.
Novel genetic markers in the 5′‐flanking region of ANKH are associated with ankylosing spondylitis
Authors: Tsui Florence W. L. , Tsui Hing Wo , Cheng Emily Y. , Stone Millicent , Payne Ursula , Reveille John D. , Shulman Marc J. , Paterson Andrew D. , Inman Robert D. 
Published: March 2003

AbstractObjectiveTo use a candidate gene approach for the identification of genetic markers that are significantly linked to and associated with ankylosing spondylitis (AS).MethodsWe searched for novel polymorphisms in the ANKH gene (human homolog of the murine progressive ankylosis gene) and genotyped 2 polymorphic sites, one in the 5′‐noncoding region and the other in the promoter region of ANKH, using DNA from affected (n = 273) and unaffected (n = 112) individuals from 124 AS families. We used these ANKH and other nearby polymorphisms to perform linkage and family‐based association analyses.ResultsWe identified 2 novel polymorphic sites: one in the 5′‐noncoding region of ANKH involving 1–2 copies of an 8‐bp repeat (denoted as ANKH‐OR), and the other in the promoter region involving different copy numbers of a triplet repeat (denoted as ANKH‐TR). ANKH‐OR and ANKH‐TR were in complete linkage disequilibrium. Five markers (D5S1953, ANKH‐TR, ANKH‐OR, D5S1954, and D5S1963) were used for both the linkage and association analyses. Multipoint linkage analysis of 124 AS families showed a modest level of significance (nonparametric linkage score 2.15; P = 0.015) at the ANKH region. The contribution of ANKH to AS susceptibility (λs) was 1.9. A family‐based association study on the same AS families revealed that both ANKH‐OR allele 1 and ANKH‐TR allele 7 were significantly associated with disease, assuming an additive model (for ANKH‐OR allele 1, P = 0.03; for ANKH‐TR allele 7, P = 0.04).ConclusionOur results indicate that ANKH‐OR and ANKH‐TR are novel genetic markers that are significantly associated with AS.