bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation of fibrous adsorbents containing amidoxime groups by radiation‐induced grafting and application to uranium recovery from sea water
Authors: Kabay N. , Katakai A. , Sugo T. , Egawa H. 
Published: April 2003

AbstractPolypropylene fibers and polyethylene hollow fibers were used as trunk polymers and were irradiated by electron beams with a dose of 200 kGy under N2 atmosphere. Grafting of acrylonitrile to those irradiated fibers was carried out at 40°C for different periods of time. The degree of grafting was determined as a function of time. The fibrous adsorbents containing amidoxime groups were prepared by the reaction of acrylonitrile‐grafted polymers with 3% hydroxylamine in a methanol–water mixture (1 : 1). Distribution of copper ions complexed with amidoxime groups at various adsorption times was obtained by electron‐probe X‐ray microanalysis. The amidoxime groups are homogeneously distributed in the cross section of fibrous adsorbents. The fibrous adsorbents based upon polypropylene fiber of 40 μm showed a remarkable kinetic behavior for Cu2+. Even after 15 min, the adsorption capacity was 2.32 mmol Cu2+ per gram of fiber. Also, the functionalization with hydroxylamine was carried out at different conditions to compare the adsorption characteristics of the resultant adsorbents. Despite having superficially different properties (elemental microanalysis, ion‐exchange capacities, adsorption capacity for UO), the polypropylene‐based fibrous adsorbents showed similar adsorption properties for uranium from sea water. The adsorption tests proved the performance of the polypropylene‐based fibrous adsorbents as a promising material for uranium recovery from sea water. In addition, uranium uptake of fibrous adsorbents increased in proportion to the volume of sea water. © 1993 John Wiley & Sons, Inc.
Natural rubber and butadiene rubber blend using diblock copolymer of isoprene–butadiene as compatibilizer
Authors: Bualek Sauvarop , Ikeda Yuko , Kohjiya Shinzo , Phaovibul Orapin , Phinyocheep Pranee , Suchiva Krisda , Utani Kazunori , Yamashita Shinzo 
Published: April 2003

AbstractBlends of natural rubber (NR) and butadiene rubber (BR) have been studied with or without diblock copolymers of isoprene–butadiene (BIR). It was found that NR/BR blends displayed the optimal properties at about 4 wt % of BIR from the tensile measurements of NR/BR blends. Increase of molecular weight of BIR resulted in the decrease of tensile properties, but had no significant effect on their hardness. Abrasion resistance of rubber blends containing BIR was about 30% higher than that without BIR. The molecular weight of BIR did not show a remarkable effect on the abrasion index. Differential scanning calorimetry and dynamic mechanical analyses of rubber blends suggested a two‐phase structure even in the presence of BIR. © 1993 John Wiley & Sons, Inc.
The properties of polymer protective coatings of optical fibers. I. The influence of active diluent concentration on the properties of UV‐cured epoxyacrylate coatings
Authors: Rayss J. , PodkośCielny W. M. , Widomski J. 
Published: April 2003

AbstractThe strong relationship between the properties of UV‐cured epoxyacrylate coatings of optical fibers and their compositions was found. The epoxyacrylate oligomer‐to‐acrylate monomer active diluent ratio was used to give a simple explanation of the mechanism of polymerization reaction of UV‐curable epoxyacrylate compositions. © 1993 John Wiley & Sons, Inc.
Modeling the process‐zone kinetics of polycarbonate
Authors: Kim A. , Garrett L. V. , Bosnyak C. P. , Chudnovsky A. 
Published: April 2003

AbstractA thermodynamic model for the equilibrial process zone ahead of a crack in polycarbonate is developed from the recently proposed Chudnovsky model and experimental characterization of the process zone. Based on the model, the force for evolution of the process zone is proposed from the consideration of irreversible thermodynamics and chemical reaction theories. The experimental data reported in our previous paper are well described by the equilibrial process zone model and a new kinetic equation. © 1993 John Wiley & Sons, Inc.
Investigation of the sequence distribution of bulk and emulsion styrene–acrylic acid copolymers by 1H‐ and 13C‐NMR
Authors: Wang Shouting , Poehlein Gary W. 
Published: April 2003

AbstractThe sequence distribution of homogeneous styrene (S)–acrylic acid (A) copolymers, obtained by low conversion (<10%) bulk copolymerization, has been studied by 1H‐ and 13C‐NMR. The reactivity ratios ra and rs were determined by the Kelen–Tudos method. The sequence distributions at the triad level were assigned and verified by Alfrey–Mayo kinetics. The sequence distributions of emulsion copolymers formed at different reaction conversions were investigated and compared with the results obtained from bulk copolymers. © 1993 John Wiley & Sons, Inc.
Ternary blends of poly(amide‐6)/polycarbonate/poly(ε‐caprolactone)
Authors: Kim Woo‐Nyon , Park Chan‐Eon , Burns Charles M. 
Published: April 2003

AbstractBlends of poly(amide‐6) (PA) and poly(ε‐caprolactone) (PCL) prepared by solution casting and screw extrusion have been investigated by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). From the measured melting point (Tm) of the solution‐cast PA/PCL blends, a Tm depression of the PA was observed for the investigated compositions. No Tm depression was found for the extruded PA/PCL blends, however. In the SEM study of the morphology of the solution‐cast PA/PCL blends, phase separation was observed between the PA phase and the PCL phase for all blend compositions. For the extruded PA/PCL blends, however, more pronounced phase separation was observed for all blend compositions. Ternary blends of PA, PCL, and bisphenol‐A polycarbonate (PC) have also been prepared by screw extrusion. From the study of morphology and extrudate swell of the PA/PC binary blends and the extruded PA/PC/PCL ternary blends, it appears that PCL could be used as a compatibilizer for the extruded PA/PC/PCL blends. © 1993 John Wiley & Sons, Inc.
Coemulsion and electrodeposition properties of mixtures of polyoxypropylene‐modified cationic epoxy resin and nonionic trimethylolpropane–toluene diisocyanate–2‐ethylhexanol crosslinker
Authors: Yang Chin‐Ping , Chen Yahn‐Haur 
Published: April 2003

AbstractThe emulsification and electrodeposition properties of mixtures of polyoxypropylene‐(POP) modified cationic epoxy resin (III) and nonionic trimethylolpropane–toluene diisocyanate–2‐ethylhexanol (TMP–TDI–2EH, V) were investigated and the compositions of their electrodeposited films were obtained by Fourier Transform Infrared (FTIR) quantitative analysis to study the effects of “soft segment” (oxypropylene groups) contained in resin III on the coemulsion and electrophoretic behavior. The results indicate that the deposition yield and throwing power of emulsion of resin III are highly dependent on its average molecular weight (Mw). Resin III with higher Mw has higher deposition yield but lower throwing power. Moreover, the deposition yield of V/III coemulsion also increases with increasing the Mw of III. On the other hand, the throwing power of V/III coemulsion is not related to the Mw of III but is influenced by the amount of soft segments in III. Increasing soft segment content in III increases the throwing power of the coemulsion. Furthermore, at the conditions providing stable coemulsion, the composition of the electrodeposited film is almost equal to the resin composition of the coemulsion. © 1993 John Wiley & Sons, Inc.
Effect of toluene on the polymerization of AN initiated by Ce(IV)–sucrose redox system in the presence of surfactants
Authors: Das H. K. , Singh B. C. 
Published: April 2003

AbstractThe effects of toluene on the kinetics of polymerization of acrylonitrile (AN) initiated by the Ce(IV)/sucrose redox system were studied in the presence of an emulsifier, N‐cetyl‐trimethylammonium bromide (NCTAB) in the temperature range 35–45°C. The effects of concentration of metal ion, monomer, sulfuric acid, substrate (sucrose), emulsifier, toluene, some inorganic salt, and organic solvent on Rp have also been investigated. The remarkable features of the investigation involve the derivation of the rate expression for the above system with the calculation of activation energy. © 1993 John Wiley & Sons, Inc.
An aromatic amine as a co‐curing agent in epoxy‐bisimide blends
Authors: Saraf M. N. , Gupta R. K. , Raman S. V. , Rajagopalan P. T. 
Published: April 2003

AbstractThe structural properties of epoxy can be retained and thermal stability improved by blending epoxy with bismaleimide (BMI) and curing them simultaneously. Depending on the curing agent, the overall viscoelastic properties of the cured material can be varied. In the present work, diaminodiphenylmethane and diaminodiphenyl sulfone have been used as curing agents to prepare blends of epoxy and BMI. The blends were characterized by DSC, TG, DMA, and SEM. Results indicate that an excellent interpenetrating network forms in both the cases and that the DDM‐cured system gives better thermal stability than that of the DDS‐cured system. © 1993 John Wiley & Sons, Inc.
In situ compatibilization of low‐density polyethylene and polydimethylsiloxane rubber blends using ethylene–methyl acrylate copolymer as a chemical compatibilizer
Authors: Santra R. N. , Samantaray B. K. , Bhowmick A. K. , Nando G. B. 
Published: April 2003

AbstractThe effect of the ethylene–methylacrylate copolymer as a chemical compatibilizer in the 50:50 blend of low‐density polyethylene (LDPE) and polydimethylsiloxane rubber (PDMS) has been studied in detail. Ethylene–methylacrylate (EMA) reacted with PDMS rubber during melt‐mixing at 180°C to form EMA‐grafted PDMS rubber (EMA‐g‐PDMS) in situ, which acted as a compatibilizer in the LDPE–PDMS rubber blend. An optimum proportion of the compatibilizer (EMA) was found to be 6 wt % based on results of dynamic mechanical analysis, adhesion studies, and phase morphology. Lap shear adhesion between the phases increased significantly on incorporation of 6 wt % of EMA. Dynamic mechanical analysis showed a single glass transition (Tg) peak at −119°C. This was further supported by X‐ray diffraction studies, which exhibited a remarkable increase in the degree of crystallinity and phase morphology and showed a drastic reduction in the size of the dispersed phase at the optimum concentration of EMA. © 1993 John Wiley & Sons, Inc.
Thermal analysis of poly(vinyl fluoride)
Authors: Hanes Mark D. , Lando Jerome B. 
Published: April 2003

AbstractA sub‐Tm transition at approximately 50°C in poly(vinyl fluoride) has been attributed to a number of physical factors. We have studied this effect using differential scanning calorimetry. The rate dependence of the endothermic peak at approximately 50°C indicates that it is a second order transition. However, the recovery behavior is time dependent. It is observed in perfect head‐to‐tail, perfectly linear polymer and thus is not a consequence of head‐to‐head or tail‐to‐tail defects or branch points. The transition appears to be a time dependent rearrangement of the polymer chains. © 1993 John Wiley & Sons, Inc.
Thermal decomposition of acrylic–SO2 copolymers
Authors: Tsonis C. P. 
Published: April 2003

AbstractThe oxidative thermal degradation of acrylic–SO2 copolymers was investigated by TG, DTG, and DTA. Their thermograms show that the copolymers decompose in several reaction stages with different weight loss, accompanied by several exo‐ and endothermic effects. Acrylonitrile–SO2 and methacrylate–SO2 copolymers exhibit a two‐stage thermal decomposition, whereas the polysulfones of the acrolein–SO2 and acrylamide–SO2 systems decompose in four stages. Both the number of SO2 units present in the copolymer and the polarity of the pendant group on the organic monomer have some effect on the thermal stability and the glass transition temperature of the polymers. © 1993 John Wiley & Sons, Inc.
The estimation of mechanical properties of polymers from molecular structure
Authors: Seitz J. T. 
Published: April 2003

AbstractThe use of semiempirical and empirical relationships have been developed to estimate the mechanical properties of polymeric materials. Based on these relationships, properties can be calculated from only five basic molecular properties. They are the molecular weight, van der Waals volume, the length and number of rotational bonds in the repeat unit, as well as the Tg of the polymer. Since these are fundamental molecular properties, they can be obtained from either purely theoretical calculations or from group contributions. The use of these techniques by polymer chemists can provide a screening technique that will significantly diminish their bench time so that they may pursue more creatively the design of new polymeric materials. © 1993 John Wiley & Sons, Inc.
Improving graft level during photoinduced graft‐copolymerization of styrene onto cotton cellulose
Authors: Shukla S. R. , Rao G. V. Gopala , Athalye A. R. 
Published: April 2003

AbstractStyrene was graft‐copolymerized onto cotton cellulose using photoinitiators uranyl nitrate (UN), ceric ammonium nitrate (CAN), and benzoin ethyl ether (BEE) under ultraviolet radiation. UN gave somewhat higher graft add‐on. Preswelling of the substrate or using divinyl benzene in the grafting bath gave an increased level of graft, the later technique being more efficient. The moisture regain and tenacity decreased, whereas thermal stability increased in proportion to the graft add‐on. © 1993 John Wiley & Sons, Inc.
Shellac film coating on metal sheets by electrochemical polymerization
Authors: Bhadani Suraj N. , Kumari Madhuri , Gupta Sumanta K. Sen 
Published: April 2003

AbstractThe electrolysis of shellac in the aqueous ammoniacal solution leads to formation of adherent films onto different metal anodes such as Fe, Cu, Pt, and Pb. The yield of deposited films increases with the time of electrolysis and current levels and is dependent on the nature of electrode materials. Therefore, the film thickness is well controlled by the impressed current level and electrolysis time. The addition of methylacrylamide to the shellac solution gives more adherent and smoother coatings onto the metal sheets than those obtained in the absence of the monomer. The film formation also takes place potentiodynamically. A plausible reaction mechanism of the shellac coating is suggested. © 1993 John Wiley & Sons, Inc.
Dialkyldithiophosphate substituted on poly(vinylchloride): Synthesis and performance
Authors: Bromberg Lev , Levin Gideon 
Published: April 2003

AbstractPreparation of sodium salt of di(2‐ethylhexyl)dithiophosphoric acid (DTPANa) by reaction of the corresponding DTPA with sodium hydride has been described. Nucleophilic substitution of chlorine on poly(vinylchloride) (PVC) by a di(2‐ethylhexyl)dithiophosphate group resulting in modified polymer (MP) was characterized by the second order rate constant equal to 6.6 × 10−5 M−1 s−1. Formation of homogeneous stable gelled phases composed of MP and DTPA, as well as MP, PVC, and DTPA, was demonstrated. The gelled material is capable of selective separation of metal ions under the conditions of extraction chromatography. © 1993 John Wiley & Sons, Inc.
Polymerization of olefins through heterogeneous catalysis XI: Gas phase sequential polymerization kinetics
Authors: Chen C. M. , Ray W. H. 
Published: April 2003

AbstractA unique series of ethylene and propylene sequential polymerization experiments have been carried out in a stirred bed gas phase reactor using unsupported Stauffer AA catalyst (TiCl3· \documentclass{article}\pagestyle{empty}\begin{document}$\frac{1}{3}$\end{document}AlCl3). Several interesting kinetic results were observed. It was found that propylene causes rate enhancement for a subsequent ethylene polymerization but that ethylene causes a rate reduction for a subsequent propylene polymerization. Furthermore, the rate enhancement/reduction effect increases with the duration of the preceding polymerization. Chemical/kinetic effects were found to be the likely causes of both the rate enhancements and the rate reductions observed during sequential polymerization. It was also shown that enhanced monomer sorption caused by the presence of a more soluble component, such as a heavier comonomer, does contribute to rate enhancement during simultaneous copolymerizations, but is not a factor for sequential polymerizations. © 1993 John Wiley & Sons, Inc.
Meadowfoam monoenoic fatty acid amides as slip and antiblock agents in polyolefin film
Authors: Swanson C. L. , Burg D. A. , Kleiman R. 
Published: April 2003

AbstractMixed monounsaturated amides (MMA) of fatty acids from meadowfoam (Limnanthes alba) were effective slip and antiblocking agents for polyethylene films. MMA may compete with extant amides as additives for manufacture of PE films if their selling price is competitive. The MMA (79% cis‐5‐eicosenoic acid amides, 17% cis‐5‐, and cis‐13‐docosenoic acid amides, and 1% cis‐5, cis‐13‐docosadienoic acid amide) required > 500 ppm but < 1000 ppm dosage to achieve high slip (coefficient of friction < 0.2) within 10 minutes of film blowing. For comparison, erucamide required < 250 ppm, oleamide required < 500 ppm, and stearamide required > 1000 ppm to give high slip levels within 10 min. Maximum antiblocking effectiveness of MMA, which developed at 1000 ppm, was equivalent to stearamide at 1000 ppm. © 1993 John Wiley & Sons, Inc.§
Polymerization of olefins through heterogeneous catalysis. XII. The influence of hydrogen in the solution copolymerization of ethylene
Authors: Jaber Isam A. , Ray W. Harmon 
Published: April 2003

AbstractThe copolymerization of ethylene with highly active TiCl4/MgCl2‐supported catalysts in solution reactors at 185°C and 400 Psig pressure is presented. The performance of these supported catalysts at these conditions is characterized by a high initial rate that decays rapidly within the 10 min polymerization period. In the presence of hydrogen and a comonomer, catalyst yields up to about 300 kg/g (Ti) are achieved. The kinetic data indicate rate enhancement when hydrogen is added in moderate concentrations. However, a high concentration of hydrogen results in a decreasing rate of ethylene consumption. Increasing the H2/C2molar ratio in the range 0–10.66 ċ 10−3leads to a reduction in theMnvalues from 31,600 to 17,400. © 1993 John Wiley & Sons, Inc.
Electrical properties of poly(vinyl chloride) compositions
Authors: Saad A. L. G. , Hassan A. M. , Gad E. A. M. 
Published: April 2003

AbstractA sample of poly(vinyl chloride) (PVC) and a polar plasticizer consisting of dioctyl phthalate (DOP) and dibutyl phthalate (DBP) was prepared and found to possess inconvenient electrical properties (permittivity, dielectric loss, and conductivity). Different samples of PVC compositions were formulated from the PVC–DOP–DBP system and also variable proportions of a copolymer of 1‐octadecene‐maleic anhydride or its hexadecylester. Lead stearate as a heat stabilizer and kaolin as a filler were added. The effect of copolymer structure on the electrical properties of the PVC–DOP–DBP system was studied to obtain a plasticized PVC of good electrical insulation character. © 1993 John Wiley & Sons, Inc.
Effect of acrylonitrile content of styrene‐co‐acrylonitrile (SAN) on morphology and electrooptical properties of polymer/liquid crystal composite films
Authors: Kim B. K. , Ok Y. S. 
Published: April 2003

AbstractEffects of copolymer composition on morphology and electrooptical properties of polymer/liquid crystal (LC) (40/60 w/w) composite films were studied with styrene‐co‐acrylonitrile (SAN) of varying acrylonitrile (AN) content (6.3–35 wt %) and a cyanobiphenyl‐type liquid crystal (E8). The dimension of the LC domain in the composite film decreased with increase of AN content of SAN up to 30 and increased at 35 wt %. The contact angle of the film with an LC drop showed a similar trend; however, its minimum was obtained at 24% AN. Threshold voltage (Vth) and rise time (τR) increased, and decay time (τD) decreased with AN content up to 30%, and the tendency is reversed at 35%. The results were interpreted in terms of, possibly, a solubility parameter matching between SAN and LC. © 1993 John Wiley & Sons, Inc.
On the applicability of the Lennard‐Jones potential function to amorphous high polymers
Authors: Arends C. B. 
Published: April 2003

AbstractPressure‐volume‐temperature measurements were performed on five amorphous thermoplastics. From these data, first derivatives of internal energy with respect to volume were calculated. These derivatives were cast into the Lennard‐Jones form and the two defining parameters were evaluated for each polymer. It was found that, when the polymer is in the glassy state, these parameters correspond to the volume and internal energy of the polymer at absolute zero. For melts, the first derivatives are constant within the accuracy of these experiments regardless of temperature, pressure, or volume. As a result, the Lennard‐Jones potential was found to be a good model for the amorphous glassy state and inappropriate above Tg. © 1993 John Wiley & Sons, Inc.
The maleinization of low molecular weight guayule rubber
Authors: Thames S. F. , Rahman A. , Poole P. W. 
Published: April 2003

AbstractThe reactions of low molecular weight Guayule rubber (LMWGR) and maleic anhydride (MA) at varying mole ratios were studied in the polar solvent, cyclohexanone, and in p‐xylene, a nonpolar solvent, by conventional free radical catalysis. Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (NMR) were used to confirm product formation and identification. © 1993 John Wiley & Sons, Inc.
Polyurethane networks based on poly(ethylene oxide)
Authors: Zulfiqar M. , Quddos A. , Zulfiqar S. 
Published: April 2003

AbstractA wide range of infinite urethane polymer networks were prepared from poly(ethylene glycol) (PEG) and hexamethylene diisocyanate (HMDI) using 1,1,1‐tris‐(hydroxymethyl) ethane (THME) as the cross‐linking agent. The influence of temperature, cross‐linking, and crystallinity on the swelling character of the hydrogel has been discussed. The toxicity of the network polymer by intravaginal implants in rats was studied. Implantation of the polymer did not result in alteration in behavior and feed intake or any pathological changes in the tissue. Vaginal fluids from the polymer‐implanted rats or the polymer extract when inoculated on a listeria monocytogene culture plate were unable to inhibit the bacterial growth. © 1993 John Wiley & Sons, Inc.
Ionotropic crosslinking of sodium carboxymethylcellulose and sodium carboxymethylcellulose‐gelatin matrices and their erosion properties
Authors: Prasad M. P. , Kalyanasundaram M. 
Published: April 2003

AbstractHydrophilic sodium carboxymethylcellulose (NaCMC) matrices were chemically modified into hydrophobic gels by ionotropic crosslinking with cupric or ferric ion under ambient temperature and pH. Insoluble matrices were also prepared using an interactive polymer gelatin in combination with NaCMC. These matrices underwent erosion at the crosslinks, followed by matrix erosion when released in water. The matrix erosion in water was influenced by the gelling agent, initial crosslinker density, and gelatin content in the insolubilized matrices. The apparent diffusion coefficients of fenthion ranged from 7.2 × 10−9 to 175.6 × 10−9 cm2/sec, with matrices prepared under different conditions. These erosion‐controlled matrices can be used for the controlled release of various biologically active agents. © 1993 John Wiley & Sons, Inc.