bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study of cryostructuration of polymer systems. XXI. Cryotropic gel formation of the water–maltodextrin systems
Authors: Lozinsky Vladimir I. , Damshkaln Lilija G. , Brown Rupert , Norton Ian T. 
Published: August 2002

AbstractThe freeze–thaw behavior of water solutions containing dissolved maltodextrin (MD; enzymatically converted potato starch derivative with MW of 8000 Da) over a wide range of MD concentration (0.1–15 g/dL) and freezing temperatures from −24 to −6°C was studied. Cryogenic treatment of these systems resulted in the formation of precipitates or gels, whose yield and thermal characteristics (fusion temperature and enthalpy) depended on the initial polymer concentration and conditions of freezing, frozen storage, and thawing. There appeared to be at least two stages to this process: (i) a rapid stage, when partial insolubilization occurred while the system was freezing, and (ii) a slower stage, the rate of which was dependent mainly on the thawing regimes used or the duration of storage at subzero temperatures. In this respect, the cryostructuration of MD was very similar to the freeze–thaw behavior of amylopectin/amylose and locust bean gum water solutions studied earlier. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1658–1667, 2002
Synthesis of liquid crystalline epoxy and its mechanical and electrical characteristics—curing reaction of LCE with diamines by DSC analysis
Authors: Lee J. Y. , Shim M. J. , Kim S. W. 
Published: August 2002

AbstractAn aromatic liquid crystalline epoxy monomer based on biphenyl mesogen was synthesized and cured with three different aromatic diamines. The curing reaction characteristics were analyzed by DSC, and the data were introduced to the Kissinger equation to attain the kinetic parameters. Diglycidyl ether of 4,4′‐biphenyl (DGEBP)/4,4′‐diaminobiphenyl (DABP), and DGEBP/4,4′‐methylenediamine (MDA) systems showed an exotherm curing reaction after comelting of the monomers; the DGEBP/p‐phenylenediamine (PDA) system's curing reaction took place in the solid state without melting of monomers. The activation energy and preexponential factor for the DGEBP/DABP system were 55.6 kJ/mol and 4.0 × 106 min−1, respectively. Those values for DGEBP/MDA and DGEBP/PDA systems were 55.1 kJ/mol and 1.0 × 106 min−1 and 148.8 kJ/mol and 7.7 × 1019 min−1, respectively. The rate constant at 100°C for DGEBP/PDA is 2 times higher than those for DGEBP/DABP and DGEBP/MDA, which have almost the same values. Strictly speaking, the rate constant of DGEBP/DABP is a little higher than that of DGEBP/MDA, and these results are in good agreement with the DSC curves. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2419–2425, 2002
Bifunctional coupling agents for improved mechanical properties in fiberglass/polyethylene composites
Authors: Van Dyke J. D. , Gnatowski Marek , Burczyk Andrew 
Published: August 2002

AbstractTwo bifunctional compounds, 12‐azido‐1‐diazo‐2‐dodecanone (A) and 1‐diazo‐17‐octadecene‐2‐one (B), show an ability to act as coupling agents in fiberglass/polyethylene composites. Under appropriate conditions the diazoketone functional groups in both A and B react with hydroxyl groups on a fiberglass surface, whereas the azide group in A and the alkene group in B form bonds with the plastic matrix during processing. FTIR and NMR spectroscopy were used to study the decomposition of each of these compounds under heat and UV light. Each treatment resulted in a relatively fast decomposition of the diazoketone functional group, along with a slower reaction of the azide and alkene groups. Thus it was possible to react the diazoketone end of these compounds with a fiberglass surface, without affecting the azide or alkene functional groups on the other ends of the molecules. In samples of treated fiberglass containing compounds A or B and mixed by extrusion with polyethylene, the mechanical properties of the composites had improved properties over composites containing untreated samples of fiberglass. With A as the coupling agent, both the tensile properties and Izod impact showed changes that indicated that a bifunctional bridge was formed between the fiberglass and polyethylene phases. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2562–2578, 2002
Physical aging of poly(diethylene glycol‐p,p′bibenzoate)
Authors: Zamfirova Galina , Misheva Marijka , Kresteva Mania , Djourelov Nikolaj , Benavente Rosario , Pérez Ernesto , Pereña José M. 
Published: August 2002

AbstractThe structure of a quenched sample of a liquid crystalline polyester, poly(diethylene glycol‐p,p′‐bibenzoate) (PDEB), and its physical aging was studied by microhardness methods (MH), wide‐angle X‐ray scattering (WAXS), and positron annihilation lifetime spectroscopy (PALS). It was established that the smectic layers in the liquid crystalline domain are oriented parallel to the sample plane. Physical aging leads to an increase of either the Vickers microhardness, directly related to the elastic modulus of the material, or the total microhardness, which includes all the components of the overall deformation. These mechanical changes are due to a decrease in the sizes of nanopores and the consequential increase of the density of the disordered phase. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2363–2368, 2002
Melt fracture behavior of polypropylene‐type resins with narrow molecular weight distribution. I. Temperature dependence
Authors: Fujiyama Mitsuyoshi , Inata Hitoshi 
Published: August 2002

AbstractPolypropylene (PP)‐type resins with narrow molecular weight distribution, such as PP‐type thermoplastic elastomer PER and controlled‐rheology PP (CRPP) made by peroxide degradation of high molecular weight PP, have a problem of easy generation of skin roughness at extrusion. To examine the present state, the occurrence of skin roughness in PER and CRPP at extrusion was investigated with a capillary rheometer in a shear rate range of 12–6100 s−1 and a temperature range of 180–280°C. A homo‐PP (HPP) and a block‐PP (BPP) with usual molecular weight distributions were used for comparison. HPP and BPP with usual molecular weight distributions show smooth extrudates at low shear rates and abruptly generate severe skin roughness “elastic failure” originating at the die entrance at a higher shear rate. PER and CRPP with narrow molecular weight distributions easily generate “sharkskin” melt fracture originating at the die exit, from a shear rate nearly one decade lower than rates of elastic failure of HPP and BPP. The sharkskin becomes more severe, with increasing shear rate, and attains to the elastic failure. The critical shear rate at which sharkskin occurs increases with increasing extrusion temperature. The critical shear rate is about 20 s−1 at 180°C and about 120 s−1 at 280°C, which is in the range encountered by the molten resin at extrusion processing. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2111–2119, 2002
Near‐infrared spectra of polyamide 6, poly(vinyl chloride), and polychlorotrifluoroethylene
Authors: De Araújo Sérgio Carvalho , Kawano Yoshio 
Published: August 2002

AbstractThe near‐infrared spectra (NIR) of polyamide 6 (PA 6), poly(vinyl chloride) (PVC), and polychlorotrifluoroethylene (PCTFE) were measured. The tentative assignment of the overtone and combination frequencies was made with curve fitting calculations and local mode theory. Anharmonicity correction and mechanical frequency were determined from a Birge–Sponer plot. Tentative assignments of stretch overtone frequencies of CH2, NH, and CO functional groups of PA 6 and CH2, and CH functional groups of PVC were made. Anharmonicity corrections of 55, 61, and 20 cm−1 were obtained for CH2, NH, and CO stretch modes of PA 6, respectively, and of 60 and 66 cm−1 for CH2 and CH stretch modes of PVC, respectively. The local mode model seems to be adequate to interpret the origin of the bands observed in NIR spectra of PA 6 and PVC. Anharmonicity corrections of 33, 19, and 16 cm−1 were obtained, respectively, for CF, asymmetrical CF2, and symmetrical CF2 stretch of PCTFE functional groups. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 199–208, 2002
Compatibilization by main‐chain thermotropic liquid crystalline ionomer of blends of PBT/PP
Authors: Zhang Ailing , Zhang Baoyan , Feng Zhiliu 
Published: August 2002

AbstractThe miscibility and mechanical properties of the blends of polybutylene terephthalate (PBT) and polypropylene (PP) with a liquid crystalline ionomer (LCI) containing a sulfonate group on the terminal unit as a compatibilizer were assessed. SEM and optical microscopy (POM) were used to examine the morphology of blends of PBT/PP compatibilized by LCI. DSC and TGA were used to discuss the thermal properties of PBT/PP blends with LCI and without LCI. The experimental results revealed that the LCI component affect, to a great extent, the miscibility and crystallization process and mechanical property of PBT/PP blends. The fact is that increasing LCI did improve miscibility of PBT/PP blends and the addition of 1% LCI to the PBT/PP blends increased the ultimate tensile strength and the ultimate elongation. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1110–1117, 2002
Synthesis and characterization of metal‐containing polyurethanes with antibacterial activity
Authors: Jayakumar R. , Rajkumar M. , Nagendran R. , Nanjundan S. 
Published: August 2002

AbstractMetal salts of mono(hydroxypentyl)phthalate [M(HPP)2, where M is Ca2+, Cd2+, Pb2+, or Zn2+] were synthesized by the reaction of 1,5‐pentane diol, phthalic anhydride, and metal acetate. A new series of metal‐containing polyurethanes containing ionic links in the main chain were synthesized by the reaction of hexamethylene diisocyanate or toluylene 2,4‐diisocyanate with the M(HPP)2 salts. The structures of the monomers and polymers were confirmed with infrared, 1H‐NMR, and 13C‐NMR spectra and elemental analysis. The polymers were also characterized with thermogravimetric analysis, differential scanning calorimetry, and solubility and viscosity measurements. The antibacterial activity of these polyurethanes was investigated with the agar diffusion method. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1194–1206, 2002
Controlled‐release polyurethane created by absorbing transition‐metal acetate and benzyl carbinol
Authors: Ye Shuji , Chen Mingcai 
Published: August 2002

AbstractThree kinds of the transition‐metal acetates were absorbed into polyurethane to investigate its effect on the desorption velocity of benzyl carbinol and ethyl alcohol from polyurethane. The results show that a small amount of transition‐metal acetate can enhance the absorption amount of benzyl carbinol and ethyl alcohol in polyurethane. With the existence of transition‐metal acetate, benzyl carbinol and ethyl alcohol desorb from polyurethane more slowly. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1170–1173, 2002
Blends of acrylonitrile–butadiene–styrene with an epoxy/cycloaliphatic amine resin: Phase‐separation behavior and morphologies
Authors: López J. , Ramírez C. , Abad M. J. , Barral L. , Cano J. , Díez F. J. 
Published: August 2002

AbstractThe phase‐separation behavior and morphologies of a commercial epoxy resin based on diglycidyl ether of bisphenol A cured with the diamine hardener 1,3‐bisaminomethylcyclohexane and blended with different amounts of acrylonitrile–butadiene–styrene thermoplastic were studied with dynamic mechanical analysis and other techniques. In comparison with the neat system, the modified systems reached before gelation and vitrification, events that were assigned to the onset and endset of the storage modulus signals in a dynamic mechanical analysis curve (storage modulus versus time). These results were explained by a phase‐separation phenomenon induced by polymerization. Scanning electron microscopy and light transmission focused on phase separation revealed a sea‐island morphology for low thermoplastic contents, a bicontinuous structure for intermediate thermoplastic contents, and an epoxy‐nodular phase‐inverted structure for high thermoplastic contents. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1277–1286, 2002
Surface photografting polymerization of vinyl acetate (VAc), maleic anhydride (MAH), and their charge transfer complex (CTC). III. VAc(3)
Authors: Deng Jian‐Ping , Yang Wan‐Tai , Rånby Bengt 
Published: August 2002

AbstractVinyl acetate (VAc) was grafted onto low‐density polyethylene (LDPE) substrates by UV irradiation with benzophenone (BP) as the photoinitiator. BP preabsorbed film samples and BP precoated film samples were prepared in advance and applied as the substrates onto which VAc was photografted, together with the method in which BP was dissolved in VAc directly. In addition, the efficiency of the polymerizations applying the preirradiation technology was examined. The conversion percent, grafting percent, and grafting efficiency were determined by a gravimetric method. The contact angles of the grafted films against water were also measured. The results show that BP preabsorbing and precoating were favorable to grafting polymerization, especially the BP precoating method, which was due to its simple operation and the ease of controlling the amount of BP. The diffusion of BP and VAc through the substrates proved to be an important factor for grafting polymerization. Through UV irradiation, dormant groups can be introduced onto LDPE film, which may be activated again by UV irradiation or by heating, leading to the formation of free radicals. Grafting polymerization can be initiated during the activation process in the presence of monomer. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1426–1433, 2001
Novel regenerable N‐halamine polymeric biocides. I. Synthesis, characterization, and antibacterial activity of hydantoin‐containing polymers
Authors: Sun Yuyu , Sun Gang 
Published: August 2002

AbstractTwo novel cyclic‐amine monomers, i.e., 3‐allyl‐5,5‐dimethylhydantoin (ADMH) and 7,8‐benzo‐3 allyl‐1,3‐diazasprio[4.5]decane‐2,4‐dione (BADDD) were synthesized with good yields by reacting allyl bromide with 5,5‐dimethylhydantoin (DMH) and 7,8‐benzo‐1,3‐diazasprio[4.5]decane‐2,4‐dione (BDDD), respectively. The synthesized monomers were characterized by FTIR and 1H‐NMR spectra, and copolymerized with acrylonitrile (AN), vinyl acetate (VAC), and methyl methacrylate (MMA) in a small monomer ratio of ADMH and BDDD, respectively. The copolymers were characterized by FTIR, 1H‐NMR, and DSC studies. The N‐halamine derivatives of the corresponding copolymers were found to exhibit high antibacterial activities against Escherichia coli, and the antibacterial properties were durable and regenerable. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2460–2467, 2001
Olefin polymerization using supported metallocene catalysts: Process representation scheme and mathematical model
Authors: Estenoz Diana A. , Chiovetta Mario G. 
Published: August 2002

AbstractA mathematical model, including the main morphological features of the polymerization process, is developed to study olefin polymerization with supported metallocene catalysts. Because the relatively large amount of methyl alumoxane (MAO) usually needed as a cocatalyst represents a disadvantage, the model introduces a scheme that simulates the results of the efforts being made in a supported catalyst to reduce MAO requirements to commercially acceptable levels. Critical fragmentation steps in the initial support‐catalyst particles that render all active sites effectively available to the monomer are specifically considered, on the basis of the support morphological characteristics. With the available reaction data, fragmentation representation alternatives are discussed and a scheme proposed. Then, a mathematical model is developed based on the above representation scheme, to calculate monomer‐concentration, temperature, and macroparticle‐size evolutions. The main features of the scheme are displayed and discussed. Both for laboratory and high‐productivity conditions, the model is used to predict changes in macro‐ and microparticle size, porosity, and concentration distribution. Predictions are employed to evaluate the impact of the initial support microparticle arrangement and fragmentation processes on the overall catalyst performance. Polymer yield, concentration profiles, and temperature transients predicted by the model are presented, showing the model application after verifying its accordance with the available experimental data. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 285–311, 2001
Kinetics of polyurethane formation between glycidyl azide polymer and a triisocyanate
Authors: Keskin Sema , Özkar Saim 
Published: August 2002

AbstractKinetics of the polyurethane formation between glycidyl azide polymer (GAP) and a polyisocyanate, Desmodur N‐100, were studied in the bulk state by using quantitative FTIR spectroscopy. The reaction was followed by monitoring the change in intensity of the absorption band at 2270 cm−1 for NCO stretching in the IR spectrum, and was shown to obey second‐order kinetics up to 50% conversion. The activation parameters were obtained from the evaluation of kinetic data at different temperatures in the range of 50–80°C. The enthalpy and entropy of activation were found to be ΔH‡ = 44.1 ± 0.5 kJ · mol−1 and ΔS‡ = −196 ± 2 J · mol−1l · K−1, respectively. Dibutyltin dilaurate (DBTDL) was used as the curing catalyst. The kinetic study of the polyurethane formation between GAP and Desmodur N‐100 showed that the reaction is enormously speeded up in the presence of the catalyst, and the reaction obeys second‐order kinetics, provided that the catalyst concentration is kept constant. An investigation on the rate of the catalysed reaction depending on the catalyst concentration provided the order of the reaction, with respect to the DBTDL catalyst concentration, and the rate constant for the catalytic pathway of the reaction. The rate constant for the catalytic pathway was established to be 4.37 at 60°C, while the uncatalyzed reaction has a rate constant of 3.88 × 10−6 L · mol−1 · s−1 at the same temperature. A rate enhancement factor of 23 was achieved by using 50 ppm catalyst. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 918–923, 2001
Raman spectroscopic study of effect of steam and carbon dioxide activation on microstructure of polyacrylonitrile‐based activated carbon fabrics
Authors: Ko Tse‐Hao , Kuo Wen‐Shyong , Hu Chung‐Hua 
Published: August 2002

AbstractThis work presents the different effects of steam and carbon dioxide activation on the microstructure of an oxidized polyacrylonitrile (PAN) fabric. An investigation was conducted on a series of carbonized fabrics and two series of activated carbon fabrics. The fabrics were activated by steam and carbon dioxide using heat‐treatment temperatures of 900–1100°C. Steam and carbon dioxide developed the microstructure initially present in the PAN‐based activated carbon fabrics, but with different effects. These fabrics in the form of fabric and powder were examined by X‐ray diffraction and Raman spectrometry. This study indicated that carbon dioxide only reacted with the crystalline edges or the irregular carbon on the fiber surface and that the inside structure of the fibers was not greatly affected. When the fabrics were activated using steam, water molecules reacted not only on the fiber surface but also with the carbon at the crystal edge and/or the nonregular carbon in the fibers, which led to communicating pore structures on the surface and in the inner portions of the fiber. This activation also promoted the denitrogenation reactions. Because of these structures and reactions, the activated carbon fabrics, which were activated by steam, had the highest stacking height for carbon layer planes (Lc), the highest number of layer planes (Lc/d002), the highest oxygen content, the largest crystal size (La), and the highest density over the other samples. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1090–1099, 2001
Preparation and properties of organosoluble, colorless, and high‐pretilt‐angle polyimides based on an alicyclic dianhydride and long‐main‐chain alkyl‐group‐containing diamines
Authors: Zhang Wei , Xu Hong‐Jie , Yin Jie , Guo Xiao‐Xia , Ye Yu‐Feng , Fang Jian‐Hua , Sui Yu , Zhu Zi‐Kang , Wang Zong‐Guang 
Published: August 2002

AbstractAlicyclic polyimides (PIs) were prepared from 3‐carboxylmethyl‐cyclopentane‐1,2,4‐tricarboxylic acid dianhydride and α,ω‐di(4‐aminophenoxyl)alkanes. These PIs possessed good solubility in aprotic, strongly polar solvents such as N‐methyl‐2‐pyrrolidone, N,N‐dimethylacetamide, N,N‐dimethyl formamide, and m‐cresol. They possessed high transparency in visible wavelengths and were almost colorless. The pretilt angle of a liquid‐crystal display with these PIs as the alignment layer increased linearly as the length of the alkyloxy groups increased; it was close to 5° for the PI samples PI‐10 and PI‐12. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2814–2820, 2001
Gas transport properties of 6FDA‐durene/1,3‐phenylenediamine (mPDA) copolyimides
Authors: Chung Tai‐Shung , Lin Wen‐Hui , Vora Rohit H. 
Published: August 2002

AbstractThe gas transport properties of He, H2, O2, N2, and CO2 for 6FDA‐durene, 6FDA‐mPDA, and their copolyimides have been investigated as a function of the composition, pressure, and temperature. The permeabilities, diffusion coefficients, and solubility coefficients follow the simple additional rules and Arrihenuis relationships for 6FDA‐durene/mPDA polyimides. The permeability decreases with an increase in pressure except He, and in the kinetic diameters of the penetrant molecules with the order of He, CO2, O2, and N2. The diffusion coefficients of O2, N2, and CO2 increase with increasing pressure and temperature. Interestingly, for these polyimides, the diffusion coefficient of O2 is larger than that of CO2. This may be caused by the strong quadrupole moment of the CO2 molecules or the difficulty in estimating the accurate diameter of CO2 molecules. The solubility coefficients decrease in the order of inherent condensability of the penetrant gases, namely CO2, O2, and N2. In addition, WAXD results show that 6FDA‐durene/mPDA polyimides are amorphous. The presence of a single glass transition temperature for these copolyimides indicates that these polyimides can be assumed to be random copolymers. They have excellent thermal stability exhibiting degradation temperature in a range of 493 to 548°C. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3552–3564, 2001
Tensile properties of Argiope trifasciata drag line silk obtained from the spider's web
Authors: Pérez‐Rigueiro J. , Elices M. , Llorca J. , Viney C. 
Published: August 2002

AbstractThe tensile properties of Argiope trifasciata (Argiopidae) drag line silk retrieved from mooring threads in the web were characterized. Scanning electron microscope images were used to determine the cross‐sectional area of the samples, allowing force‐displacement plots to be rescaled as stress–strain curves and to characterize fracture surfaces. Twenty‐eight samples were tested to obtain statistically significant values of the mechanical parameters (elastic modulus, stress and strain at the proportional limit, and tensile strength). The tensile strength of the material was subjected to a Weibull analysis—the first time that this has been attempted with a spider silk. A low value of the Weibull modulus, m = 3.4, was obtained, demonstrating that drag line monofilament does not have a sufficiently reliable tensile strength to function as an engineering material on its own. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2245–2251, 2001