bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of plasticizer type and storage conditions on properties of poly(methyl vinyl ether‐co‐maleic anhydride) bioadhesive films
Authors: McCarron Paul A. , Woolfson A. David , Donnelly Ryan F. , Andrews Gavin P. , Zawislak Agnieszka , Price John H. 
Published: December 2003

AbstractPoly(methyl vinyl ether‐co‐maleic anhydride) formed films from aqueous formulations with characteristics that are ideal as a basis for producing a drug‐containing bioadhesive delivery system when plasticized with a monohydroxyl functionalized plasticizer. Hence, films containing a novel plasticizer, tripropylene glycol methyl ether (TPME), maintained their adhesive strength and tensile properties when packaged in aluminized foil for extended periods of time. Films plasticized with commonly used polyhydric alcohols, such as the glycerol in this study, underwent an esterification reaction that led to polymer crosslinking, as shown in NMR studies. These revealed the presence of peaks in the ester/carbonyl region, suggesting that glyceride residue formation had been initiated. Given the polyfunctional nature of glycerol, progressive esterification would result in a polyester network and an accompanying profound alteration in the physical characteristics. Indeed, films became brittle over time with a loss of both the aqueous solubility and bioadhesion to porcine skin. In addition, a swelling index was measurable after 7 days, a property not seen with those films containing TPME. This change in bioadhesive strength and pliability was independent of the packaging conditions, rendering the films that contain glycerol as unsuitable as a basis for topical bioadhesive delivery of drug substances. Consequently, films containing TPME have potential as an alternative formulation strategy. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1576–1589, 2004
Performance of neural networks for predicting yarn properties using principal component analysis
Authors: Chattopadhyay R. , Guha Anirban , Jayadeva  
Published: December 2003

AbstractIn recent years, neural networks have been used as a tool for modeling an industrial process. An improvement in their performance may be expected either by divining more efficient training algorithms or by intelligently manipulating the data set. The second method is examined. The problem chosen is one of predicting the properties of cotton yarn from the fiber properties. When the input data are known to correlate with each other, principal component analysis can be used to improve the performance of neural networks. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1746–1751, 2004
Studies of electrical and mechanical properties of poly(vinyl chloride) mixed with electrically conductive additives
Authors: Saad A. L. G. , Aziz H. A. , Dimitry O. I. H. 
Published: December 2003

AbstractDifferent samples of poly(vinyl chloride) (PVC) compositions were formulated from PVC, a polar plasticizer such as dioctylphthalate (DOP), and variable proportions of electrically conductive additives such as fast extrusion furnace (FEF) carbon black (CB), poly(vinylpyridine) (PVP), or polyacrylonitrile (PAN). Epoxidized soybean oil was added as a heat stabilizer. Samples of the PVC–CB system were also prepared by dispersing different concentrations of CB into the PVC matrix. The electrical studies showed that the addition of CB to the PVC–DOP system produces a plasticized PVC with high electrical conductivity whereas the compounding of PVC with CB produces a sample with much higher electrical conductivity. The effect of the structure of PVP and PAN on the electrical and mechanical properties of the PVC–DOP system was also studied to obtain a semiconductive plasticized PVC with good mechanical properties. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1590–1598, 2004
Poly(N‐vinylcarbazole)–clay nanocomposite materials prepared by photoinitiated polymerization with triarylsulfonium salt initiator
Authors: Yu Yuan‐Hsiang , Lin Ching‐Yi , Yeh Jui‐Ming 
Published: December 2003

AbstractA series of polymer–clay nanocomposite (PCN) materials that consist of poly(N‐vinylcarbazole) (PNVC) and layered montmorillonite (MMT) clay are prepared by effectively dispersing the inorganic nanolayers of MMT in an organic PNVC matrix via in situ photoinitiated polymerization with triarylsulfonium salt as the initiator. Organic NVC monomers are first intercalated into the interlayer regions of the organophilic clay hosts, followed by one‐step UV‐radiation polymerization. The as‐synthesized PCN materials are typically characterized by Fourier transform IR spectroscopy, wide‐angle X‐ray diffraction, and transmission electron microscopy. The molecular weights of PNVCs extracted from the PCN materials and the bulk PNVC are determined by gel permeation chromatography analysis with tetrahydrofuran as the eluant. The morphological image of the synthesized materials is observed by an optical polarizing microscope. The effects of the material composition on the optical properties and thermal stability of PNVCs and a series of PCN materials (solution and fine powder) are also studied by UV–visible absorption spectra measurements, thermogravimetric analysis, and differential scanning calorimetry, respectively. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1904–1912, 2004
Self crosslinkable blends of polychloroprene and phosphorylated cashew nut shell liquid prepolymer
Authors: Menon A. R. R. , Visconte L. L. Y. 
Published: December 2003

AbstractThe self crosslinking behavior of polychloroprene rubber (CR) containing phosphorylated cashew nut shell liquid (PCNSL) prepolymer was studied. The cure characteristics and kinetics of crosslinking of blends of CR and PCNSL were determined using an oscillating disk rheometer. The extent of crosslinking was determined from chemical crosslink density index obtained by equilibrium swelling method in a solvent. Evidence for heat induced self crosslinking was obtained from FTIR spectroscopy. It was found that 5 to 10 phr of PCNSL accelerates the heat induced self crosslinking behavior of CR. The effect of conventional curatives and fillers on the cure characteristics and mechanical properties of CR was also studied and compared. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1619–1625, 2004
Uptake of Pb(II) and Cd(II) by a new phenolformaldehyde polymer resin derived by the insertion of sulfur ligands in the form of xanthate
Authors: Reddy A. Ravikumar , Reddy K. Hussain 
Published: December 2003

AbstractA new phenolformaldehyde polymer resin containing potential soft‐type donor atoms (sulfur atoms) was synthesized by the reaction of sodium salt of 2,4‐dihydroxyacetophenone formaldehyde resin with carbon disulfide. The resin was characterized by elemental analysis, IR, and 1H‐NMR spectral studies. Because of its insolubility in aqueous media, the resin was successfully used in the removal of Pb(II) and Cd(II). Parameters such as the effect of pH, the effect of time, competitive studies, the effect of initial metal‐ion concentration, and the recyclability of the polymer resin were studied. The amount of metal removed by the resin was determined with atomic absorption spectrophotometry. The retention properties were strongly dependent on pH. The elution of metal ions was investigated in acid media. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1932–1936, 2004
Morphology, crystallization and melting properties of isotactic polypropylene blended with lignin
Authors: Canetti Maurizio , De Chirico Aurelio , Audisio Guido 
Published: December 2003

AbstractThe influence of lignin (L) on the thermal properties and kinetics of crystallization of isotactic polypropylene (PP) is reported in this article. PP blends containing 5 and 15 wt % of L were prepared by mixing the components in a screw mixer. An increase of the thermal degradation temperature of the blends was observed as a function of L content. The crystallization and thermal behavior of the pure PP and of the PP/L blends were analyzed by differential scanning calorimetry (DSC). Isothermal crystallization kinetics were described by means of the Avrami equation, which suggests a three‐dimensional growth of crystalline units, developed by heterogeneous nucleation. The isothermal growth rate of PP spherulites was studied using a polarizing optical microscope. The enhancement of PP crystallization rate for the PP/L blends was observed and ascribed to the nucleating action of lignin particles. Non‐isothermal crystallization kinetics were applied, according to the results elaborated by Ziabicki and the method modified by Jeziorny. The kinetic crystallizability of the PP is not influenced by the L present in the blend. In the presence of L, PP can simultaneously crystallize in both the α and β crystalline forms, and the ratio between the α and β forms was determined by X‐ray diffraction analysis. Two melting peaks relative to the two crystalline form of PP were observed for the PP/L blends, for all isothermal crystallization temperatures investigated by means of DSC. The equilibrium melting temperature for α‐form of pure PP was obtained. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1435–1442, 2004
Experimental and theoretical studies of polymer/solvent viscosity mixtures
Authors: Modarress Hamid , Mohsen‐Nia Mohsen , Mahdavi Mahmood Akhavan 
Published: December 2003

AbstractViscosity of the binary mixtures of polymers/solvent: (polystyrene/toluene), (polymethylmethacrylate/acetone), (polystyrene/benzene), (polystyrene/cyclohexane), and (polymethylmethacrylate/chloroform) were measured at different temperatures by a Haake viscometer. The samples of polymer/solvents mixtures used in the viscometry measurements were in low concentration of polymer (maximum concentration 0.25 g/cm3). The measured viscosities were used to evaluate the parameters of the modified Eyring's viscosity equation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1724–1729, 2004
Kinetics of the in situ polymerization and in situ compatibilization of poly(propylene) and polyamide 6 blends
Authors: Hu Guo‐Hua , Cartier Hervé , Feng Lian‐Fang , Li Bo‐Geng 
Published: December 2003

AbstractIn previous articles, we reported on a novel reactive extrusion process to obtain a compatibilized blend of polymer A and polymer B. It consisted in polymerizing the monomer of polymer A in the presence of polymer B. A fraction of the latter contained initiating sites from which the polymerization of monomer A took place. As such, both polymer A and a graft copolymer of polymer A and polymer B were formed in the process. That process was called in situ polymerization and in situ compatibilization of polymer blends. Its feasibility was illustrated for in situ polymerized and in situ compatibilized poly(propylene) and polyamide 6 (PP/PA6) blends. The latter were prepared by activated anionic polymerization of ϵ‐caprolactam (CL) in the presence of PP in a batch mixer and a twin‐screw extruder, respectively. A fraction of the PP contained isocyanate groups from which PA6 grafts were formed. Sodium caprolactam (NaCL) was used as the catalyst and a diisocyanate compound was used as the activator. In this study, we report on the effects of various parameters on the kinetics of the anionic polymerization of CL in the presence of PP. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1498–1504, 2004
Dielectric strength of the blends of virgin and recycled HDPE
Authors: Cruz S. A. , Zanin M. 
Published: December 2003

AbstractThis work evaluated the incorporation of recycled high‐density polyethylene (HPDE) in the virgin polymer by measuring its dielectric strength. Post‐consumer containers of HDPE were collected and passed through the basic processes of plastics recovery: washing, grinding, and drying. Formulations were elaborated containing 0, 25, 50, 75, and 100% of recycled material incorporated to the virgin resin by extrusion and injection processes, stabilized with 0.2% Irganox B215. Samples of these materials were submitted to dielectric breakdown analysis by using an electrode‐type sphere—plane and ramp of positive electric tension. The data were treated and analyzed by using the statistical distribution of Weibull, and the Maximum Likelihood method. The degree of crystallinity was measured by X‐ray diffraction. Atomic absorption spectrophotometry was employed to identify metallic residues present in the samples. The results showed that there is a 17% decrease in the values of the dielectric strength when we compare the virgin HDPE with the 100% recycled. Therefore, formulations containing up to 50% of recycled material may be taken into consideration in the development of products in electric insulating systems.© 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91:1730–1735, 2004
Study of microwave irradiation polymerization mechanism in the presence of carriers
Authors: Lu Jianmei , Ji Shun‐Jun , Wu Jianfei , Guo Feng , Zhou Hui , Zhu Xiulin 
Published: December 2003

AbstractMicrowave irradiation polymerization was studied in the presence of a carrier. The influence of different carriers, such as Al2O3, SiO2, and MgO on the microwave irradiation polymerization mechanism of acrylamide and 2‐ethylhexyl acrylate was studied by adopting polymerization inhibitors such as an anionic inhibitor, cationic inhibitor, and radical inhibitor hydroquinone. When the system contains the carriers Al2O3 and SiO2, the polymerization mechanism occurs according to a radical mechanism, but when the system contains MgO, the polymerization mechanism occurs according to not only a radical mechanism but also an anionic polymerization mechanism with superficial grafting occurring. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1519–1524, 2004
Compatibilized blends of PVC/PA12 and PVC/PP containing poly(lauryl lactam‐block‐caprolactone)
Authors: Kim Byong Jun , White James L. 
Published: December 2003

AbstractSpecially designed block copolymers have played a role as compatibilizing agents in the system of immiscible polymer blends. We applied lauryl lactam (LA)–caprolactone (CL) block copolymer [P(LA‐b‐CL)] as a compatibilizing agent for immiscible poly(vinyl chloride) (PVC) blends with various polymers. These blends possess high thermal performance and toughness. We investigated the effect of P(LA‐b‐CL) as a compatibilizing agent for immiscible PVC blends with poly(ω‐lauryl lactam) [polyamide 12 (PA12)]. We also described the invention of a new compatibilizing agent system involving P(LA‐b‐CL) for PVC/polypropylene (PP) blends. The mechanical and thermal properties of (1) PVC/PA12 blend compatibilized with P(LA‐b‐CL) and (2) PVC/PP blend compatibilized with P(LA‐b‐CL)/PA12/maleic anhydride–modified PP were both enhanced. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1983‐1992, 2004
Bonding of vulcanized rubber to polyester cord using RFL adhesives modified with chlororesorcinolic resin
Authors: Hamed G. R. , Ruksakulpiwat C. 
Published: December 2003

AbstractA typical resorcinol/formaldehyde/latex (RFL) adhesive and two modified versions were used to bond a tire body stock (NR/SBR/BR blend) to polyethylene terephthalate (PET) cord. Modifications contained a commercial chlorophenol/resorcinol condensate or a lab‐prepared chlororesorcinol/resorcinol condensate (CRA). Standard H‐test specimens were prepared by embedding adhesive‐coated, heat‐treated cords into the rubber and then vulcanizing. The effect of heat treatment time and overcure on pull‐out adhesion was studied. Overcure conditions were used to simulate long service. Pull‐out forces increased with longer heat treatment and decreased with overcure. The CRA‐modified adhesive gave the highest pull‐out forces after overcure. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91:1993–1996, 2004
An analysis of the changes in the structure and tensile properties of polytetrafluoroethylene films under vacuum ultraviolet irradiation
Authors: Peng Guirong , Geng Hongbin , Lü Zushun , Yang Dezhuang , He Shiyu 
Published: December 2003

AbstractThe effect of 5–200 nm of vacuum ultraviolet (VUV) irradiation on the structure and tensile properties of polytetrafluoroethylene (PTFE) films was investigated. The change in structure before and after VUV irradiation was evaluated with differential scanning calorimetry (DSC) and electron spin resonance (ESR) analysis. DSC analysis results showed that the melting point, melting enthalpy, and crystallization enthalpy increased and the maximum crystallization temperature decreased a little with increasing VUV dose. It was deduced from the DSC data that the molecular weight of the PTFE films decreased and the destruction of the crystal structure took place under VUV irradiation. The ESR results showed that the radicals formed under VUV irradiation were chain‐end radicals and peroxy radicals, which may have been formed due to the scission of carbon‐to‐carbon bonds. The tensile fracture strength and elongation decreased with increasing VUV irradiation dose. Under the same irradiation dose, the tensile properties were more sensitive to the lower VUV intensity. The decrease in the molecular weight and the destruction of crystal structure might have been the major reasons for the deterioration of the tensile properties. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1494–1497, 2004
Synthesis, characterization, and partial hydrolysis of polyisoprene‐co‐poly(tert‐butyl methacrylate) and electrorheological properties of its suspensions
Authors: Yavuz Mustafa , Ibrahim Ünal Halil 
Published: December 2003

AbstractThe synthesis, characterization, partial hydrolysis, and salt formation of polyisoprene‐co‐poly(tert‐butyl methacrylate) and the electrorheological properties of its suspensions were investigated. The copolymer was characterized by gel permeation chromatography, viscosity measurements, 1H‐NMR, Fourier transform infrared spectroscopy, particle size measurements, and elemental analysis. The poly(tert‐butyl methacrylate) units of the copolymer were partially hydrolyzed by p‐toluene sulfonic acid monohydrate and then converted into a lithium salt. The conductivity of this copolymeric salt was measured to be 1.4 × 10−9 S cm−1. Suspensions of the copolymeric salt were prepared in four insulating oils (silicone oil, mineral oil, trioctyl trimellitate, and dioctyl phatalate) in a series of concentrations (5–33%, m/m). The gravitational stabilities of these suspensions were determined at 20 and 80°C. The flow times of the suspensions were measured under no electric field (electric field strength = 0) and under an applied electric field (electric field strength ≠ 0), and the electrorheological activity was observed. Furthermore, the effects of the solid particle concentration, the shear rate, the electric field strength, a high temperature, and the addition of promoters on the electrorheological activities of the suspensions were investigated, and the excess shear stresses were determined. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1822–1833, 2004
Polymer nanocomposites formation by the use of sodium montmorillonite dispersion in alcohol and a cationic surfactant
Authors: Sasaki Akinobu , White James L. 
Published: December 2003

AbstractTo enhance the formation of nanocomposites, we pretreated montmorillonite clay with a high‐boiling‐point alcohol or a combination of the alcohol and a cationic surfactant prior to melt mixing. The polymer matrix was melt‐mixed with sodium montmorillonite treated with alcohol or a combination of the alcohol and a cationic surfactant, and then, the alcohol was removed. This new method was applied to polymethyl methacrylate, polystyrene, polyethylene, and polypropylene compounds. The dual use of a surfactant and an alcohol for the treatment of montmorillonite enabled a high degree of intercalation of montmorillonite layers by polymethyl methacrylate chains, which was not obtained in untreated clay or clay treated with either the surfactant or alcohol individually. The process was not as successful with the polyhydrocarbons. There was some evidence for slightly enhanced intercalation for polystyrene, but there was less evidence for polyethylene and polypropylene. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1951–1957, 2004
Gas permeation performance of cellulose hollow fiber membranes made from the cellulose/N‐methylmorpholine‐N‐oxide/H2O system
Authors: Jie Xingming , Cao Yiming , Lin Bin , Yuan Quan 
Published: December 2003

AbstractCellulose hollow fiber membranes (CHFM) were prepared using a spinning solution containing N‐methylmorpholine‐N‐oxide as solvent and water as a nonsolvent additive. Water was also used as both the internal and external coagulant. It was demonstrated that the phase separation mechanism of this system was delayed demixing. The CHFM was revealed to be homogeneously dense structure after desiccation. The gas permeation properties of CO2, N2, CH4, and H2 through CHFM were investigated as a function of membrane water content and operation pressure. The water content of CHFM had crucial influence on gas permeation performance, and the permeation rates of all gases increased sharply with the increase of membrane water content. The permeation rate of CO2 increased with the increase of operation pressure, which has no significant effect on N2, H2, and CH4. At the end of this article a detailed comparison of gas permeation performance and mechanism between the CHFM and cellulose acetate flat membrane was given. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1873–1880, 2004
Increased oxidative stress with aging reduces chondrocyte survival: Correlation with intracellular glutathione levels
Authors: Carlo Marcello Del , Loeser Richard F. 
Published: December 2003

AbstractObjectiveTo examine the role of oxidative stress in mediating cell death in chondrocytes isolated from the articular cartilage of young and old adult human tissue donors.MethodsCell death induced by the oxidant SIN‐1 was evaluated in the alginate bead culture system using fluorescent probes to assess membrane integrity. Generation of peroxynitrite by the decomposition of SIN‐1 was confirmed by positive immunostaining of treated cells for 3‐nitrotyrosine. Determinations of oxidized glutathione (GSSG) and reduced glutathione (GSH) were performed in monolayer cultures using an enzyme‐ recycling assay. Cells were depleted of intracellular glutathione either by the addition of DL‐buthionine‐(S,R)‐sulfoximine or by removal of L‐cystine from the culture media. The activity of cellular antioxidant enzymes was determined spectrophotometrically by the decay of substrate from the reaction mixture.ResultsMore chondrocytes (>2‐fold) from old donors (≥50 years) died after exposure to 1 mM SIN‐1 relative to those derived from young donors (18–49 years). Although autocrine production of insulin‐like growth factor 1 (IGF‐1) promotes chondrocyte survival, pretreatment with IGF‐1 could not prevent the cell death induced by SIN‐1 exposure. Cells isolated from old donors had a higher ratio of GSSG to GSH. Glutathione reductase is the principal enzyme involved in the regeneration of GSH from GSSG. Treatment of chondrocytes with SIN‐1 to induce oxidative stress in vitro resulted in the decreased activity of glutathione reductase and thioredoxin reductase, but not catalase. Cells depleted of intracellular glutathione were more susceptible to cell death induced by SIN‐1.ConclusionThese results provide evidence that increased oxidative stress with aging makes chondrocytes more susceptible to oxidant‐mediated cell death through the dysregulation of the glutathione antioxidant system. This may represent an important contributing factor to the development of osteoarthritis in older adults.