bluuebunny/crossref_metadata_2025_split huggingface dataset:
Elongation flow studies of DNA as a function of temperature
Authors: Sasaki N. , Maki Y. , Nakata M. 
Published: August 2002

AbstractThe response of T4‐phage DNA molecules to an elongational flow field was monitored by flow‐induced birefringence as a function of temperature. The flow‐induced birefringence observed in this study was localized in the pure elongational flow area with a critical strain rate, indicating that the birefringence was attributed to a coil–stretch transition of DNA molecules. The slight decrease in the birefringence intensity with increases in temperature to 40°C was explained by a thermal‐activation process. At temperatures above 50°C, flow‐induced birefringence decreased remarkably, and no birefringence was observed at temperatures above 60°C. After the flow experiments, ambient temperature was reduced back to room temperature, and flow experiments at room temperature were performed again. Flow‐induced birefringence was recovered almost completely in samples for which the first flow measurements were made at temperatures below 53°C. Irreversible changes were observed for samples for which the first flow experiments were performed at temperatures above 55°C. The temperature dependence of UV‐absorption spectra revealed that the double‐strand DNA helix began to partially untwine at a temperature over 50°C, and duplexes became almost completely untwined at a temperature over 55°C. A comparison of electrophoresis patterns for untwined molecules showed that flow‐induced scission of DNA molecules occurred in a sample solution in flow experiments performed at 65°C, while no molecular weight reduction was observed in the sample solution at 55°C. In this article, this difference between the untwined DNA molecules is discussed on the basis of the thermally activated bond scission (TABS) model. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1357–1365, 2002
Pervaporation of volatile organic compounds/water mixtures through poly(1H,1H,9H‐hexadecafluorononyl methacrylate)‐filled poly(1‐trimethylsilyl‐1‐propyne) membranes
Authors: Mishima S. , Nakagawa T. 
Published: August 2002

AbstractPoly(1‐trimethylsilyl‐1‐propyne) (PMSP) is a glassy polymer that contains many microvoids. The permselectivity of the PMSP membrane is controlled by the microvoids, and its permeation behavior is different from rubbery polymer membranes. PMSP membrane was filled with poly(1H,1H,9H‐hexadecafluorononyl methacrylate) (PHDFNMA), and the solution‐diffusion mechanism during pervaporation was investigated. Separation performance was increased due to the introduced hydrophobic polymer, PHDFNMA, as compared to the PMSP membrane. For the 62 wt % PHDFNMA‐filled PMSP membrane, the permselectivity was significantly enhanced. The microvoids in the PMSP membrane play an important role in permselectivity. As the feed of ethyl butanoate (EBU) concentration increased and the EBU quantity sorbed into the PHDFNMA‐filled PMSP membrane increased, the diffusion of water was prevented; in turn, the water flux decreased. At a low feed concentration, the diffusivity of the EBU molecule was much lower than that of water due to the larger molecular size of EBU. As EBU was sufficiently sorbed into the membrane, the diffusion of water was prevented by the EBU molecules; in turn, the permselectivity of EBU significantly increased. At a high‐feed EBU concentration, the diffusion of water increased, and the diffusion of EBU decreased to a constant as the PHDFNMA‐filled PMSP membrane was plasticized. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1054–1060, 2002
Structure and physical properties of cellulose acetate/poly(butylene succinate) blends containing a transition metal alkoxide
Authors: Uesaka Takahiro , Ogata Nobuo , Nakane Koji , Shimizu Katsuji , Ogihara Takashi 
Published: August 2002

AbstractTwo biodegradable polymers, that is, poly(butylene succinate) (BN) and cellulose acetate (CA), were solvent‐cast blended with chloroform. Homogeneous films were obtained from the blend by the addition of tetraisopropyl titanate (TP) as a compatibilizer. We measured the viscosity of the blend solution to investigate the function of TP during the blending process. From the measurement, we conclude that there are interactions among TP, BN, and CA. From optical observation and thermal measurements of the blend films, we found that the structure of blends is in a pseudostable state and that the addition of TP makes the structure units small. From thermogravimetric analyses, we found that the addition of TP decreases the thermal decomposition temperature of the BN/CA blends. From the measurements of mechanical properties of the blends, we found that changing the blend ratio can produce the materials with a wide range of mechanical properties. The hydrolysis of the blends was investigated. The molecular scission of BN/CA blends takes place uniformly not only from the outside but also from the inside of the films. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1750–1758, 2002
Reactions of hydroxymethyl derivatives of uric acid with oxiranes. II. An analysis of reaction course and product structure
Authors: Cisek‐Cicirko Irmina , Lubczak Jacek 
Published: August 2002

AbstractPolyetherols containing thermostable purine rings are obtained in reactions of hydroxymethyl derivatives of uric acid with an excess of ethylene oxide or propylene oxide. By using elementary analytical tools and 1H‐NMR spectroscopy, it was possible to follow the course of reaction at various molar ratios of reagents. A migration of formaldehyde molecules from N‐hydroxymethyl groups or from oligooxymethylene bridges to the end of oxyalkyl chains was observed. At the same time, the O‐hydroxymethyl groups are successively blocked by oxiranes. The most probable structure of polyetherols is proposed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1955–1962, 2002
Grafting of polystyrene branches to polyethylene and polypropylene
Authors: Park Eun‐Soo , Jin Hyoung‐Joon , Lee Ik‐Mo , Kim Mal‐Nam , Lee Han Sup , Yoon Jin‐San 
Published: August 2002

AbstractPolyethylene (PE) and polypropylene (PP) were reacted with benzoyl peroxide (BPO) and 2,2,6,6‐tetramethyl‐1‐piperidinyloxy (TEMPO) to prepare PE‐TEMPO and PP‐TEMPO macroinitiators, respectively. Molecular weight of PP decreased, whereas that of PE increased during the reaction with the BPO/TEMPO system. Polystyrene (PS) branches were grafted to PE and PP backbone chains as a result of bulk polymerization of styrene with the PE‐TEMPO and PP‐TEMPO macroinitiators. A significant amount of PS homopolymer was produced as a byproduct. Weight of the resulting PE‐g‐PS and PP‐g‐PS increased with the polymerization time up to 20 h and then leveled off. Melting point of PE and PP domains in PE‐g‐PS and PP‐g‐PS, respectively, lowered as the content of PS in the copolymers increased. However, glass transition of the copolymers was almost identical with that of PS homopolymer, indicating that the constituents in the copolymers were all phase‐separated from each other. In scanning electron microscopy of the incompatible PE/PS, PP/PS, and PE/PP/PS compounded with PE‐g‐PS and PP‐g‐PS, any clear indication of enhanced adhesion between the phases was not observed. However, phase domains in the blends were, nevertheless, reduced significantly to raise mechanical properties such as maximum stress and elongation at break by 20–75%. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1103–1111, 2002
Melting‐reactive dyes for mass coloration of nylon based on blend compatibilization: Perylene‐3,4,9,10‐tetracarboxylic acid dianhydride
Authors: Meng Qinghua , Huang Deyin , Chen Lin , Wei Shaohua 
Published: August 2002

AbstractThe mass coloration of nylon‐1010 with a melting‐reactive dye, an economically favorable and environmentally friendly method of coloration, is described. Perylene‐3,4,9,10‐tetracarboxylic acid dianhydride (PTAD) was used as a melting‐reactive dye for nylon‐1010, and it showed high thermal stability. A chain‐extending reaction was confirmed by an ultraviolet–visible spectroscopic analysis. The effect of the proportion of added PTAD on the intrinsic viscosity of the polymer was studied, and increased amounts resulted in increased intrinsic viscosity. The light fastness of the colored fibers was found to be 4. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2164–2167, 2002
Study of the processing chemistry of polyimides with thermogravimetry/Fourier transform infrared/mass spectrometry techniques
Authors: Xie Wei , Heltsley Rebecca , Li Han‐Xu , Lee Charles , Pan Wei‐Ping 
Published: August 2002

AbstractOne of the fundamental aspects of the carbon fiber‐reinforced, high‐temperature polyimide composite AFR700B/T650‐35, namely, the curing chemistry involved in the polyimide formation, was studied in real time with thermogravimetry/Fourier transform infrared (FTIR)/mass spectrometry (MS) evolved‐gas analysis techniques. The off‐gas reaction products identified by FTIR and MS essentially confirmed the literature polyimide curing mechanisms. However, the FTIR/MS data obtained could also accommodate a reversed curing chemistry in which the elimination of water from amide ester formation occurred first and was followed by the release of methanol from subsequent imidization. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2213–2224, 2002
Study of polyurethane/sulfonated dimethyl fumarate complex
Authors: Zhu Weihua , Tian Liying , Ren Tianbin , Wang Xinling , Tang Xiaozhen , Li Gang 
Published: August 2002

AbstractIn this study linear polyether polyurethanes (PU) and sulfonated dimethyl fumarate (SDMF) were successfully synthesized and a series of novel solid polymer electrolytes, based on the complexes of PU and SDMF, were prepared. Fourier transform–Raman spectroscopy (FT‐Raman), 1H‐NMR, differential scanning calorimetry (DSC), atomic force microscopy (AFM), and complex impedance analysis were utilized to investigate the chemical structure, microscale morphology, and ionic conductive property of this system. Results show that the ionic conductivity of the PU/SDMF series increases with increasing temperature. In the salt concentration range investigated, there is a maximum ionic conductivity for the PU/SDMF system. When the molar ratio of the ether oxygen and sodium cation is about 24, the optimum compatibility between the hard and soft segments is realized and the highest soft‐segment Tg is reached. A further increase in salt concentration causes the aggregation and precipitation of SDMF, and the decrease of the soft‐segment Tg. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 67–74, 2002; DOI 10.1002/app.10205
Photografting of methacrylic acid on polyethylene film: Effect of mixed solvents consisting of water and organic solvent
Authors: Irwan Ginting Suka , Kuroda Shin‐Ichi , Kubota Hitoshi , Kondo Takashi 
Published: August 2002

AbstractPhotografting of methacrylic acid (MAA) on linear low‐density polyethylene film (thickness = 30 μm) was investigated at 60°C in mixed solvents consisting of water and organic solvent with xanthone as the photoiniator. The organic solvents examined were acetone, methanol, tetrahydrofuran, and dioxane. A maximum percentage of grafting was observed at a certain concentration of organic solvent in the mixed solvent, depending on the nature of the organic solvent. Distribution of the grafted chains in the resultant MAA‐grafted film, which was examined by scanning electron microscopy and attenuated total‐reflection IR spectroscopy, was largely influenced by the use of the mixed solvent. The grafted samples swelled in the alkaline region and shrank in acidic medium, showing a pH‐responsive character. The extent of the pH‐responsive function was closely related to the location of grafted chains, which could be controlled by proper choice of the composition of organic solvent in the mixed solvent. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2454–2461, 2002
Electrochemical synthesis of poly[2‐hydroxyethylmethacrylate] hydrogel: Kinetics and mechanism
Authors: Prashantha K. , Vasanta K. , Pai Kumar , Sherigara B. S. 
Published: August 2002

Abstract2‐Hydroxyethylmethacrylate (HEMA) was polymerized in an aqueous sulfuric acid–N,N‐dimethylformamide (DMF) medium in a divided cell by an electrolytically generated mediator species titanium(III). Titanium(III)–hydroxylamine sulfate was used as the initiator redox system. The reaction was confined to the cathode compartment and was found to proceed via a free radical mechanism. Kinetics of polymerization were investigated for variation in initial monomer concentrations, acid concentrations, electrical currents, dielectric constants of the solvent medium, and electrode materials. Chain termination of the polymer was due to coupling of growing macroradicals; also, a fraction of the termination took place by a chain transfer mechanism involving the organic solvent molecules. A suitable mechanism for titanium(III)–hydroxylamine sulfate mediated indirect electropolymerization of HEMA has been proposed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 983–992, 2002; DOI 10.1002/app.10299
Distribution and diffusion coefficients of NaCl in polyamide (nylon‐6,6 and polyxylyleneadipamide) membranes
Authors: Ohya H. , Semenova S. , Mizoguchi K. , Ogihara J. , Fukaya S. , Suzuki Y. , Aihara M. , Negishi Y. 
Published: August 2002

AbstractThin membranes of an aliphatic polyamide (nylon‐6,6) and an aromatic polyamide (polyxylyleneadipamide) (PXAP) were prepared, and their distribution (K) and overall diffusion (D) coefficients of sodium chloride were measured with the unsteady‐state and steady‐state dialysis method. The overall diffusion coefficients at a zero concentration [D(0)] of sodium chloride for nylon‐6,6 and PXAP were 1.3–0.8 μm2/s (from 2 min of interfacial polymerization to 4 min) and 0.078, respectively. D(0) for PXAP was about 3 times greater than that of a cellulose acetate (CA) membrane (0.024 μm2/s). The K values for nylon‐6,6 and PXAP were 0.7–0.5 from 2 to 4 min and 0.05, respectively. K for PXAP was almost the same as K for CA (0.06). A two‐part (dense and porous) model of the membrane structure was applied to obtain Dd (the diffusion coefficient in the dense part of the membrane) and Dp (the diffusion coefficient in the porous part of the membrane) for CA, PXAP, and nylon‐6,6 thin membranes. The values of Dd were almost the same for both nylon‐6,6 and PXAP (0.05–0.061 μm2/s) and about 10 times greater than the value for the CA membrane (5.6 × 10−3 μm2/s). Dp for PXAP was almost the same as Dp for CA. However, Dp for the nylon‐6,6 membrane was 10–16 times greater than Dp for the PXAP membrane. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2605–2612, 2002
Polypropylene–intumescent flame‐retardant composites based on meleated polypropylene as a coupling agent
Authors: Ma Zhi‐Ling , Gao Jun‐Gang , Niu Hai‐Jun , Ding Hai‐Tao , Zhang Jie 
Published: August 2002

AbstractThe phosphoric acid‐pentaerythritol‐melamine copolymer, which is composed of three main components of intumescent flame retardant (IFR) and has optimal intumescent degree, was selected as IFR. The influence of meleated polypropylene (PP‐g‐MAH) on the properties and compatibility of IFR polypropylene (PP) composites were studied. The results obtained from mechanical tests, rheological behavior of composites, and scanning electron microscope showed that PP‐g‐MAH was a true coupling agent for IFR/PP blends and did not change the necessary flame retardancy. The cocrystallization between bulk PP and PP segments of PP‐g‐MAH was also proven by WAXD analysis. Flow test showed that the flow behaviors of composites in the melt are those of a pseudoplastic and it is very small for PP‐g‐MAH affecting rheological behavior of the PP/IFR composite. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 257–262, 2002
Formation of micron‐sized cycloolefin copolymer from toluene solution using compressed HFC‐134a as antisolvent
Authors: Hsu Ren‐Yong , Tan Chung‐Sung , Chen Jen‐Min 
Published: August 2002

AbstractA precipitation process employing 1,1,1,2‐tetrafluoroethane (HFC‐134a) as antisolvent was studied to see its feasibility for the separation of cycloolefin copolymer (COC) from toluene solution. The precipitation was carried out by spraying toluene solution containing 3 to 12 wt % of COC through a 0.4‐mm nozzle into a compressed HFC‐134a environment. More than 95% of COC could be precipitated under the conditions that both gas and liquid HFC‐134a phases were present in the precipitator. The effects of temperature, pressure, COC concentration, HFC‐134a flow rate, toluene solution flow rate, and liquid level in the precipitator on yield and morphology of the precipitated COC were systematically studied. Microspheres of COC with a narrow size distribution were exhibited for the COC concentration equal to or less than 5 wt %. The precipitation at these COC concentrations followed a nucleation and growth mechanism. Nucleation and solution breakup that affected morphology and size of the precipitated COC were allowed to occur in the gas space above the liquid. For the concentrations of 8, 10, and 12 wt %, fibers and films instead of microspheres were exhibited. The porosity of the precipitated COC was found to decrease with increasing the COC concentration, indicating that the precipitation was under a spinodal decomposition mechanism. The molecular weight and glass‐transition temperature of the precipitated COC were found to be sufficiently close to those of the virgin chips, indicating that HFC‐134a is an appropriate antisolvent to achieve separation of polymer from solution. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1657–1668, 2002; DOI 10.1002/app.10543
Thermal degradation of the epoxy system BADGE n = 0/1,2‐DCH immersed in hydrochloric acid
Authors: Núñez M. R. , Núñez Lisardo , Villanueva M. , Rial B. 
Published: August 2002

AbstractThe thermal degradation of an epoxy system consisting of diglycidyl ether of bisphenol‐A and 1,2‐diamine cyclohexane (BADGE n = 0/1,2‐DCH), immersed in hydrochloric acid for 30 days, was studied by thermogravimetric analysis, to determine the reaction mechanism of the degradation process. The results were compared with experimental data corresponding to the same epoxy system without exposure to the acid. It was found that the kinetic reaction mechanism changed with the immersion in HCl. The average activation energy of the solid‐state process was determined by using the Flynn‐Wall‐Ozawa method, resulting in 81 ± 2 kJ/mol. Different integral and differential methods and different reaction mechanisms reported in the literature were used and compared to this value. Analysis of experimental results suggests that in the conversion range studied, 5–20%, the reaction mechanism is somewhere between the different types of phase boundary controlled reaction and random nucleation with one nucleus on the individual particle. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 371–375, 2002
New optically active poly(ester‐imide)s derived from N,N′‐(4,4′‐carbonyldiphthaloyl)‐bis‐L‐phenylalanine diacid chloride
Authors: Mallakpour Shadpour E. , Hajipour Abdol‐Reza , Zamanlou Mohammad‐Reza 
Published: August 2002

AbstractNew optically active poly(ester‐imide)s containing benzophenone tetracarboxylic and L‐phenylalanine moieties were synthesized from N,N′(4,4′‐carbonyldiphthaloyl)‐Bis‐L‐phenylalanine diacid chloride (1) with several aromatic diols such as phenolphthalein (2a), hydroquinone (2b), 2,4‐dihydroxyacetophenone (2c), 1,8‐dihydroxyanthraquinone (2d), bisphenol‐A (2e), 1,5‐dihydroxynaphthalene (2f), 1,4‐dihydroxyanthraquinone (2g) and 4,4′‐dihydroxybiphenyl (2h) by low‐temperature solution polycondensation in CHCl3/Et3N solution. The polymerization reactions were started at 0°C and proceeded at room temperature, producing a series of optically active poly (ester‐imide)s with inherent viscosities of about 0.12–0.31 dL g−1. All of the above polymers are optically active and have been fully characterized by IR spectroscopy, elemental analyses, and specific rotation. Thermal properties of the poly(ester‐imide)s have been investigated using thermal gravimetric analysis. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 315–320, 2002
Crosslinking in polyethylene films by oxidation on metals
Authors: Lin D. G. , Vorobieva E. V. 
Published: August 2002

AbstractThe kinetics of oxidative conversions, such as accumulation of carbonyl groups and crosslinks in polyethylene films that were subjected to oxidation on metallic substrates differing in activity (e.g., copper and aluminum), was investigated. It was learned that the rate and ultimate level of crosslinking in the polymer oxidized on copper were higher than those on aluminum. It is believed that this situation is related to the catalytic effect of the copper compounds transferred into the polymer volume at the regimes of contact oxidation. The amounts of transferred metal were approximately equal in both the soluble and the insoluble fractions of the polymer. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2776–2783, 2002
Insolubilization of sodium chondroitin sulfate by forming a semi‐interpenetrating polymer network with acrylic acid: A potential carrier for colon‐specific drug delivery
Authors: Wang L. F. , Wang J. M. , Chiang Y. L. 
Published: August 2002

AbstractTo reduce the highly hydrophilic property of chondroitin sulfate (ChS), a semi‐interpenetrating polymer network (semi‐IPN) of chondroitin sulfate/polyacrylic acid (PAA) was prepared as a drug carrier by crosslinking acrylic acid with diethyleneglycol diacrylate. The swelling properties of the semi‐IPNs with different concentrations of crosslinking agent were correlated. The moisture sorption profiles were evaluated using differential thermal analysis. Ketoprofen was used as a drug probe to evaluate the performance of the drug released from the semi‐IPN matrices. The prepared semi‐IPNs demonstrated significant swelling reduction properties with both gastric and intestinal fluids compared with those of both the pure ChS and the ChSAA blend without the crosslinking agent. The amount of accumulated drug released from the semi‐IPNs was less than 30 wt % at pH 1.2 and up to 80 wt % at pH 7.4. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 114–122, 2002
Effect of the pressure on the crystallization behavior of polyamide 66
Authors: Won J. C. , Fulchiron R. , Douillard A. , Chabert B. , Varlet J. , Chomier D. 
Published: August 2002

AbstractThe crystallization behavior of polyamide 66 under high pressure up to 2500 bar was investigated by the use of dilatometric and calorimetric techniques in nonisothermal and isothermal conditions. The solid–solid Brill transition is detected from the evolution of the specific volume in the PVT diagram. The variation of supercooling was examined under different pressures and temperatures. In nonisothermal conditions, when the same cooling rate is applied, the crystallization supercooling is not changed for different pressures. In isothermal conditions, for a given temperature, a pressure increase extends the crystallization supercooling. By the analysis of melting peaks of samples crystallized in different conditions of pressure and temperature, we can conclude that the increasing of the crystallization supercooling leads to a decrease of the lamellae thickness. Finally, the evolution of the thermodynamic equilibrium melting temperature according to pressure was examined. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1021–1029, 2001