bluuebunny/crossref_metadata_2025_split huggingface dataset:
Middle Ear Disease in Children with Congenital Velopharyngeal Insufficiency
Authors: Sheahan Patrick , Miller Ian , Earley Michael J. , Sheahan Jerome N. , Blayney Alexander W. 
Published: June 2004

Objective To examine the incidence and natural history of middle ear disease in children with congenital velopharyngeal insufficiency (VPI) without cleft palate. Setting and Subjects Children with congenital VPI attending the combined cleft clinic at a tertiary cleft center. The diagnosis of congenital VPI in all cases was confirmed be the observation of hypernasality, nasal air escape, or both by a speech and language therapist and the demonstration of incompetence of the velopharyngeal sphincter by means of nasoendoscopy or videofluoroscopy. Children with overt cleft palate or postsurgical VPI were excluded. Design The children's medical records were reviewed, and a questionnaire regarding history of ear problems was sent to all parents. Children were divided into those with Pruzansky type I VPI (showing bifid uvula, midline diastasis of soft palate, or submucous cleft of the hard palate) and Pruzansky type II VPI (no visible stigmata). Main Outcome Measures Incidence of reported ear problems, ear infections, hearing loss, and surgical intervention for middle ear disease in the whole group and in each of the subgroups. Results Seventy-one parents returned completed questionnaires. The overall incidence of middle ear disease was 63%, with 28% reported to have below-normal hearing. There was no significant difference between children with Pruzansky types I and II VPI with respect to incidence of otopathology or hearing loss. Conclusions Irrespective of the presence of any visible palatal abnormalities, children with congenital VPI showed a substantial incidence of otopathology and should thus be closely monitored.
Synthesis, spectral and DSC analysis of glycidyl azide polymers containing different initiating diol units
Authors: Murali Mohan Y. , Padmanabha Raju M. , Mohana Raju K. 
Published: June 2004

AbstractGlycidyl azide polymers (GAPs), containing different diol units, were prepared by treating the corresponding poly(epichlorohydrin)s (PECHs) with sodium azide in DMF solvent at 110°C for 8–10 h. The poly(epichlorohydrin)s containing different diol units were synthesized by the polymerization of epichlorohydrin using borontrifluoride etherate as initiator in the presence of a small amount of low molecular weight diols. The formation of these PECHs was confirmed by IR spectroscopy. The nature of terminal hydroxyl group present in the polymer chain was confirmed by proton NMR spectroscopy. The structure of GAPs containing different initiating diol units was confirmed by UV, IR, and proton NMR spectral analysis. Thermal properties of the GAPs were evaluated using differential scanning calorimetry; the stabilities and glass‐transition temperatures of the GAPs varied according to the initiating diol unit present in the polymer chains. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2157–2163, 2004
Elastomeric composites. I. Silicone composites
Authors: Bokobza Liliane 
Published: June 2004

AbstractThe reinforcement of poly(dimethylsiloxane) (silicone rubber) imparted by different types of fillers was investigated. Three different techniques of incorporation of silica were compared: the usual blending process, in situ filling process, and introduction of spherical colloidal silicas (Stöber silicas). In addition, results obtained with other types of fillers—layered silicates and fibrous clays—were discussed. The role of filler is assessed essentially through the mechanical properties of the silicone composites. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2095–2104, 2004
Glass transition and mechanical properties of PLLA and PDLLA‐PGA copolymer blends
Authors: Nakafuku Chitoshi , Takehisa Shin‐ya 
Published: June 2004

AbstractThe change of the glass transition temperatures (Tg) in the blend of poly(L‐lactic acid) (PLLA) and the copolymers of poly(D,L‐lactic acid) and poly(glycolic acid) (PDLLA‐PGA) with different D,L‐lactic acid and glycolic acid composition ratio (50 : 50, 65 : 35, and 75 : 25) was studied by DSC. Dynamic mechanical measurement and tensile testing were performed at various temperatures around Tg of the blend. In the blend of PLLA and PDLLA‐PGA50 (composition ratio of PDLLA and PGA 50 : 50), Tg decreased from that of PLLA (about 58°C) to that of PDLLA‐PGA50 (about 30°C). A single step decrease was observed in the DSC curve around Tg between the weight fraction of PLLA (W(PLLA)) 1.0 and 0.7 (about 52°C) but two‐step changes in the curve are observed between W(PLLA) = 0.6 and 0.3. The Tg change between that of PLLA and that of PDLLA‐PGA and the appearance of two Tgs suggest the existence of PLLA rich amorphous region and PDLLA‐PGA copolymer rich amorphous region in the blend. A single step decrease of E′ occurs at around Tg of the pure PLLA but the two‐step decrease was observed at W(PLLA) = 0.6 and 0.4, supporting the existence of the PLLA rich region and PDLLA‐PGA rich region. Tensile testing for various blends at elevated temperature showed that the extension without yielding occurred above Tg of the blend. Partial miscibility is suggested for PLLA and PDLLA‐PGA copolymer blends. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2164–2173, 2004
A novel fluorescence temperature sensor based on a surfactant‐free PVA/borax/2‐naphthol hydrogel network system
Authors: Lee Sang Min , Chung Woo Young , Kim Jong Kyu , Suh Dong Hack 
Published: June 2004

AbstractThis article is a report about the novel fluorescence temperature sensor based on a surfactant‐free Poly (vinly alcohol)/borax/2‐naphthol hydrogel system. The well‐known fluorescence indicator, 2‐naphthol, exhibits a change of fluorescence intensity when it is embedded in aqueous PVA/borax gel networks at various temperatures. The blue color emission intensity(PL:λmax = 426 nm) of 2‐naphthol in a basic hydrogel changed gradually to strong from 30°C to 80°C when excitation wavelength was 365 nm. The pH change in the hydrogel system was in the range from 8.50 at 30°C to 9.35 at 80°C with rising temperature.In the case of salicylic acid, the blue color emission intensity in the acidic gel decreases with rising temperature when excitation wavelength was 365 nm in all cases. The pH change in the hydrogel system was from 2.80 at 30°C to 2.40 at 80°C with rising temperature. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2114–2118, 2004
Thermally induced homolytic scissions of interunitary bonds in a softwood lignin solution: A spin‐trapping study
Authors: Seino T. , Yoshioka A. , Takai M. , Tabata M. 
Published: June 2004

AbstractUnstable chemical species, that is, radicals generated by the thermal treatment of a dimethyl sulfoxide (DMSO) solution of the lignin of a softwood, Yezo spruce (Picea jezoensis Carr.), were studied in detail with an electron spin resonance (ESR) method combined with a spin‐trapping technique. An unstable secondary carbon radical (∼CH ·) in the solution was trapped as a stable nitroxide spin adduct [R(NO ·)CH∼ (R = tert‐butyl benzene)] when the DMSO solution was heat‐treated in the presence of a spin‐trapping reagent [2,4,6‐tri‐tert‐butylnitrosobenzene (BNB)] at about 40°C. This meant that alkyl phenyl ether bonds (∼CHO‐phenyl), known as interunitary lignin bonds, were homolytically scissioned by the thermal treatment in the lignin solution. A detailed analysis of the ESR spectrum revealed that three kinds of radicals—primary (∼CH2 ·), secondary (∼CH ·), and tertiary (∼C ·) carbon radicals—were trapped as stable spin adducts at about 60°C, although the phenoxy radical (PhO ·) was not trapped by the BNB spin trap as the counter radical of the secondary carbon radical. This suggested that a fairly large steric hindrance existed between the so‐called guaiacoxy radical with a methoxy group in the ortho position and the BNB molecule bearing two butyl groups as bulky moieties in the ortho positions. However, the phenoxy radicals in the lignin solution were stable up to about 60°C. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2136–2141, 2004
Study of the composition effect of glass ceramic and silver on poly(vinyl butyral) thermal degradation with thermogravimetric analysis
Authors: Liau Leo Chau‐Kuang , Liau Jing‐Yi , Chen Yen‐Tai 
Published: June 2004

AbstractThe thermal degradation of poly(vinyl butyral) (PVB)/glass ceramic, PVB/Ag, and PVB/glass ceramic/Ag composites was investigated with thermogravimetric analysis in nitrogen and air. Thermogravimetric data revealed that the compositions of both inorganic materials in air could greatly influence the thermal degradation of PVB. The degradation reactions of PVB/ceramic and PVB/Ag composites began earlier and accelerated rapidly at lower temperatures. The overall degradation period was obviously shortened for the thermal degradation of PVB/Ag in air, whereas a longer time was required for the PVB/ceramic composite than for PVB. Moreover, dual effects of ceramic and Ag on the thermal degradation of PVB were observed for PVB/ceramic/Ag composites. In addition, the catalytic effects of ceramic and Ag on the degradation reaction of PVB in air were verified with a kinetic analysis. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2142–2149, 2004
Structural and physical properties of silk fibroin/alginate blend sponges
Authors: Lee Kwang‐Gill , Kweon HaeYong , Yeo Joo‐Hong , Woo Soon‐Ok , Lee Jang‐Hern , Hwan Park Young 
Published: June 2004

AbstractSilk fibroin/alginate blend sponges were examined through IR spectroscopy, X‐ray diffractometry, and differential scanning calorimetry to determine the structural changes of silk fibroin. The effects of fibroin/alginate blend ratios on the physical and mechanical properties were investigated to discover the feasibility of using these blend sponges as biomedical materials such as wound dressings. The compressive modulus of silk fibroin was increased up to 30 kPa, from 7.1 kPa, by blending with alginate. Thermal crystallization behavior of fibroin induced by heat treatment was restricted by blending with alginate. In spite of that, the structural characteristics of fibroin were not changed by incorporation with alginate. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2174–2179, 2004
Study on temperature‐resistant properties of polymer–matrix solid film lubricants
Authors: Gao Jintang , Shao Xin , Feng Bo , Zhao Jiazheng , Mao Shaolan 
Published: June 2004

AbstractThe temperature‐resistant properties of some polymer–matrix solid film lubricants were studied. Different chemically modified methods were used in this study to enhance, their temperature‐resistant properties. The friction and wear mechanism of polymer–matrix solid film lubricants rubbing at different temperatures in air were explored with differential scanning calorimetry (DSC), scanning electron microscope (SEM), and X‐ray photoelectron spectroscopy (XPS). The test results showed that the blending modification of polymer and the application of certain of filler were beneficial to enhance heat resistance of polymer–matrix solid film lubricants, and therefore, improved their lubricating properties at different temperatures in air. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2180–2184, 2004
A rapid microwave‐assisted solvent extraction method for assessment of stabilizer concentration in crosslinked polydimethylsiloxane
Authors: Fateh‐Alavi K. , Karlsson S. , Gedde U. W. 
Published: June 2004

AbstractCrosslinked polydimethylsiloxanes were prepared containing 0.05 to 0.2 wt % of either a phenolic antioxidant (Irganox® 1010) or a hindered amine stabilizer (Tinuvin® 144). The stabilizer concentration was assessed by HPLC and UV‐Vis spectroscopy of Soxhlet and microwave‐assisted solvent extracts. Almost complete recovery of stabilizer was achieved with Soxhlet extraction. High stabilizer recovery was achieved when acetone was used as the solvent in the microwave‐assisted extraction. HPLC was shown to be an efficient method for determining the concentration of Irganox 1010. For Tinuvin 144 the selectivity of both UV‐Vis spectroscopy and HPLC was poor, leading to imprecise evaluation of the antioxidant concentration. The loss of stabilizer by migration from polymer to hot water (75 and 95°C) was monitored for the systems stabilized with Irganox 1010 and the diffusion coefficient of the antioxidant in the polymer was determined. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2185–2192, 2004
Compatibility in immiscible polysulfone/poly(ethylene terephthalate) blends
Authors: Retolaza A. , Eguiazábal J. I. , Nazábal J. 
Published: June 2004

AbstractPolysulfone (PSU)/poly(ethylene terephthalate) (PET) blends were obtained by direct injection molding across the composition range. Their phase behavior, thermal properties, morphology, and mechanical properties were measured. The blends were composed of a pure PSU amorphous phase and either a pure PET phase in PSU‐poor blends, or a PET‐rich phase with some dissolved PSU in PSU‐rich blends. The morphology of the dispersed phase was mostly spherical with some elongated particles in the PET‐rich blends. A slight synergistic behavior was observed in the Young's modulus, mainly in the 90/10 blend, which is probably due to orientation effects. The presence of some broken particles indicated some interfacial adhesion. The ductility values were approximately linear with composition. This was generally the case in PSU‐rich blends, and was attributed to the higher level of PSU in the PET‐rich phase. Although embrittlement was seen in blends with 30% of the second component, the ductility of the two pure components did not significantly decrease after annealing due to the presence of low amounts (up to 10%) of another component of the blend. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2193–2200, 2004
Epoxy‐montmorillonite clay nanocomposites: Synthesis and characterization
Authors: Nigam Vineeta , Setua D. K. , Mathur G. N. , Kar Kamal K. 
Published: June 2004

AbstractNanocomposites of epoxy resin with montmorillonite clay were synthesized by swelling of different proportions of the clay in a diglycidyl ether of bisphenol‐A followed by in situ polymerization with aromatic diamine as a curing agent. The montmorillonite was modified with octadecylamine and made organophilic. The organoclay was found to be intercalated easily by incorporation of the epoxy precursor and the clay galleries were simultaneously expanded. However, Na‐montmorillonite clay could not be intercalated during the mixing or through the curing process. Curing temperature was found to provide a balance between the reaction rate of the epoxy precursor and the diffusion rate of the curing agent into the clay galleries. The cure kinetics were studied by differential scanning calorimetry. The exfoliation behavior of the organoclay system was investigated by X‐ray diffraction. Thermogravimetric analysis was used to determine the thermal stability, which was correlated with the ionic exchange between the organic species and the silicate layers. The morphology of the nanocomposites was evaluated by scanning electron microscopy. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2201–2210, 2004
Application of microwave irradiation for synthesis of novel optically active poly(amide imides) derived from diacid chloride containing epiclon and L‐isoleucine with aromatic diamines
Authors: Mallakpour Shadpor , Kowsari Elaheh 
Published: June 2004

AbstractEpiclon [3a,4,5,7a‐tetrahydro‐7‐methyl‐5‐(tetrahydro‐2,5‐dioxo‐3‐furanyl)‐1,3‐isobenzofurandione] or [5‐(2,5‐dioxotetrahydrofurfuryl)‐3‐methyl‐3‐cyclohexyl‐1,2‐dicarboxylic acid anhydride] (1) was reacted with L‐isoleucine (2) in acetic acid and the resulting imide acid (3) was obtained in high yield. The diacid chloride (4) was obtained from diacid derivative (3) by reaction with thionyl chloride. The polycondensation reaction of diacid chloride (4) with several aromatic diamines such as 4,4′‐sulfonyldianiline (5a), 4,4′‐diaminodiphenyl methane (5b), 4,4′‐diaminodiphenylether (5c), p‐phenylenediamine (5d), m‐phenylenediamine (5e), 2,4‐diaminotoluene (5f), and 4,4′‐diaminobiphenyl (5g) was developed by using a domestic microwave oven in the presence of a small amount of a polar organic medium such as o‐cresol. The polymerization reactions were also performed in two other different methods: low‐temperature solution polycondensation and reflux conditions. A series of optically active poly(amide imides) with inherent viscosity of 0.12–0.30 dL/g were obtained. All of the above polymers were fully characterized by IR, elemental analyses, and specific rotation techniques. Some structural characterizations and physical properties of these optically active poly(amide imides) are reported. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2218–2229, 2004
A novel modification on melt intercalation via exothermal MMT
Authors: Wang Xin , Lin Jingjing , Wang Xuyun , Wang Zhaobo 
Published: June 2004

AbstractThis article presented a novel modification on the melt intercalation. Montmorillonite (MMT) with exothermal enthalpy effect was prepared by the compounding of MMT with AIBN in solution. An exfoliated polystyrene (PS)/MMT nanocomposites could be obtained by the introduction of exothermal MMT via melt mixing, and the comparison with the counterpart indicated the exfoliation of MMT was accelerated by the in situ exothermal enthalpy and nitrogen released during melt intercalation. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2230–2236, 2004
Compatibilization of a polyolefin blend through covalent and ionic coupling of grafted polypropylene and polyethylene. II. Morphology
Authors: Colbeaux Aimeline , Fenouillot Françoise , Gerard Jean‐François , Taha Mohamed , Wautier Henri 
Published: June 2004

AbstractThe morphology of a polypropylene/polyethylene (PP/PE) blend and a maleic anhydride modified PP and PE (PPg/PEg) blend was studied. The initial morphology, at the extruder die, after the melt blending into a twin‐screw extruder, was first characterized. Then, the evolution of this initial morphology was followed after a injection molding operation, and during annealing in an oven at 200°C. The influence of the compatibilization of the blend by coupling reactions through covalent (with 1,12‐diaminododécane) and ionic reactions (with zinc acetate and sodium hydrogenocarbonate) was also investigated. At the extruder die, the viscosity ratio proved to be a determinant factor governing the dispersed phase diameter of the droplets, and as a second factor, the addition of small amounts of coupling‐agents together with (PPg/PEg) to (PP/PE) resulted in a decrease of the diameter of the droplets. The injection molding of these initial blends resulted in important coalescence and in an elongation of the dispersed phase. This was observed for the non compatibilized and also for some of the compatibilized blends. The ionic coupling showed a good stabilization of the morphology. Finally, the morphology of the non compatibilized blends was found to be instable when the material was annealed at 200°C. The average size of the dispersed phase increased. The coupling reactions delayed the occurrence of the coalescence about 5 min and limited its effects. The extent of the coarsening depended strongly on the composition of the blend and on the nature of the coupling. Still, the ionic agents appeared more effective. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2237–2244, 2004
Acrylamide‐grafted‐acacia gum polymer matrix tablets as erosion‐controlled drug delivery systems
Authors: Toti Udaya S. , Soppimath Kumaresh S. , Mallikarjuna Nadagouda N. , Aminabhavi Tejraj M. 
Published: June 2004

AbstractAcrylamide was grafted onto acacia gum in different ratios (1 : 1, 1 : 3, and 1 : 5). The graft copolymers formed were characterized by FTIR, rheological measurements, and differential thermal analysis. Tablets were prepared from these polymers loaded with two antihypertensive drugs, viz., diltiazem hydrochloride and nifedipine. The in vitro release experiments were carried out in simulated gastric and intestinal conditions. The graft copolymer prepared in the ratio 1 : 5 of acacia gum : acrylamide matrix was found to be a suitable matrix to investigate the controlled release of diltiazem hydrochloride and nifedipine. The drug release continued up to 6 and 14 h, respectively, for diltiazem hydrochloride and nifedipine. The release mechanism was investigated by using the mathematical equations proposed by Higuchi, Hixson‐Crowell, and Kopcha. Based on the release kinetics data, a correlation was attempted between the erosion‐controlled release and the dissolution‐controlled release. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2245–2253, 2004
Methanol‐ and ethanol‐induced convex deformation and macrovoid formation of poly(methyl methacrylate)
Authors: Lin C. B. , Chen C. S. , Chen Zhi‐Hong , Su Nan‐Ching 
Published: June 2004

AbstractMethanol‐ and ethanol‐induced convex deformation and macrovoid formation in poly(methyl methacrylate) (PMMA) through sandwich structures, consisting of polycarbonate (PC)/PMMA/PC was investigated. The sandwich structures had a circular hole on the outer PC layer, which allowed the solvent to contact with PMMA. Both single‐convex and double‐convex deformations of the PMMA layer were produced, depending upon the hole diameter. For a fixed hole diameter, there was an optimum PMMA thickness, which produced maximum curvature for the double‐convex deformation. The physical mechanism for these phenomena can be well explained by the relative strength of the swelling stress and the deformation resistance of the PMMA layer. We also used the wet phase‐inversion method to produce porous convex deformation for the sandwich structures. The size, number, and location of the convex pores can be prescribed. This may have potential applications in local filtering and other areas. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2254–2261, 2004
Formation of multilayer poly(acrylic acid)/poly(vinylidene fluoride) composite membranes for pervaporation
Authors: Lin Dar‐Jong , Chang Cheng‐Liang , Shaw Horng‐Yue , Jeng Yi‐Su , Cheng Liao‐Ping 
Published: June 2004

AbstractDual‐ and multilayer composite membranes, consisting of poly(acrylic acid) (PAA) and poly(vinylidene fluoride) (PVDF), were synthesized by the plasma‐induced polymerization technique. The dual‐layer membrane had a dense PAA layer grafted onto a microporous PVDF substrate, whereas in the multilayer membranes, the grafted PAA and the PVDF layers were arranged in an alternating sequence (e.g., PAA/PVDF/PAA and PAA/PVDF/PAA/PVDF/PAA). These membranes were used in a pervaporation process to separate ethanol–water solutions. For the dual‐layer membranes, the results indicated that the separation factor increased and the permeation flux decreased with increasing amounts of grafted PAA. For the case of grafting yield < 0.6 mg/cm2, the composite membrane demonstrated poor separation. As the grafting yield reached 0.85 mg/cm2, a sharp increase of the separation factor was observed. For the multilayer membranes, the pervaporation performances were very good, with high separation factors (on the order of 100) and reasonable permeation fluxes over a wide ethanol concentration range. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2266–2274, 2004