bluuebunny/crossref_metadata_2025 huggingface dataset:
Grafting of poly(acrylic acid) onto cellulosic microfibers and continuous cellulose filaments and characterization
Authors: Loría‐Bastarrachea M. I. , Carrillo‐Escalante H. J. , Aguilar‐Vega M. J.
Published: August 2002

Results from the grafting of poly(acrylic acid) (PAA) onto cellulosic microfibers and continuous cellulose filaments are presented. The grafting of PAA onto cellulosic fibers offers the possibility of developing enhanced ion exchange and fluid absorbency on the fibers. The grafting of PAA was carried out with a two‐step procedure. First, vinyl‐terminated ethoxy silane was deposited on the surface of the fiber. This was followed by a grafting polymerization reaction in aqueous media of acrylic acid with different concentrations of potassium persulfate (KPS), which acted as the initiator. The percentage of grafting increased with increasing KPS concentration and reached a maximum value at a concentration of about 0.4 wt % with respect to the weight of the fiber. The grafted copolymer was characterized by Fourier transform infrared spectroscopy. Strong evidence that the grafting reaction was successful was given by the presence of a band, with a maximum at 1732 cm−1, that was characteristic of carbonyl group absorption and was not initially present in the cellulosic fibers. The water absorption of the cellulosic microfibers grafted with PAA was three times greater than the water absorption of the nongrafted microfibers. The mechanical properties of continuous cellulose filaments did not change drastically with PAA grafting. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 386–393, 2002
Study of the crystal structure of P(HBA/HNA)/PET blend fibers
Authors: Xiao Changfa , Zhang Yufeng , Wu Shizhen , Takahashi Toshisada
Published: August 2002

The crystal structure of p‐hydroxybenzoate/2‐hydroxy‐6‐naphthoic acid copolyester [P(HBA/HNA)]/poly(ethylene terephthalate) (PET) blend (ACPET) fiber was studied with wide‐angle X‐ray diffraction and differential scanning calorimetry. The results showed that crystallites of P(HBA/HNA) and PET were formed in ACPET fibers; that is, some crystallites of ACPET fiber were composed of PET chains, and others were composed of P(HBA/HNA) chains. The thermal behaviors of the crystals of each component in the blend fiber were different from those of each corresponding pure component. For the fibers heat‐treated at 300 and 350°C, the degree of supercooling of P(HBA/HNA) segments in the blend fibers was the same as that of P(HBA/HNA) fiber, but the degree of supercooling of PET in the blend fibers was distinctly higher than that of pure PET fibers. Evidently, the aforementioned changes were attributable to the blending of PET with P(HBA/HNA). © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 394–400, 2002
Competitive sorption of water vapor and CO2 in photocrosslinked PVCA film for a capacitive‐type humidity sensor
Authors: Matsuguchi Masanobu , Maeda Nozomi , Sakai Yoshiro
Published: August 2002

The sorption behavior of water vapor and CO2 gas in photocrosslinked poly(vinyl cinnamate) (PVCA) film was examined at 30°C under atmospheric pressure. Both the water sorption isotherm and the CO2 sorption isotherm obtained with quartz crystal microbalance (QCM) method obeyed the simple Langmuir's equation. Water vapor/CO2 mixed‐gas sorption isotherms were also obtained. Total amount of sorbed mixed gases was clearly influenced by the partial pressure of water vapor (pw) and CO2 gas (pc) in the atmosphere. A modified Langmuir's equation based on a dual‐site model was employed for predicting the competitive adsorption isotherm, and the isotherm was clearly described by the equation. The theoretically estimated amount of adsorbed water at the constant pw decreased slightly with increasing pc. The effect of this phenomenon on the sensitivity of the capacitive‐type relative humidity sensor was examined. As expected, the electrical capacitance of the sensor at the constant relative humidity decreased because of the coexistence of CO2 gas. However, the influence was quite small in the CO2 concentration range in the ordinary environment. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 401–407, 2002
Studies on compression behavior of carbon–epoxy laminates with and without buffer‐strip layers in dry and water‐absorbed conditions
Authors: Kishore  , Khan Bijoysri , Viswanath B.
Published: August 2002

This work looks at the compression behavior of laminated carbon–epoxy (C–E) composites with inserted interleaved polytetrafluoroethylene‐coated fabric material at different locations either continuously or discontinuously within the specimen. Also, the effect of water ingress in these specimens on the strength values is reported. Although significant differences were noticed in the trend of the strengths for different architectural arrangements in dry and water‐immersed samples, significant differences for the modulus was less perceptible. The introduction of small amounts of less‐adherent layers of material at specific locations causes a decrement in the load‐carrying capability of the C–E system. It is further observed that with an increase in the number of buffer/delaminating strips insertions, the water ingress increases and the compressive strength values decrease. Examination of the samples, noting macroscopic features including the interfacial regions, assisted in observing a correlation between the observed strength values, architecture, and the failure mode. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 408–416, 2002
Synthesis of poly(vinyl alcohol) phosphorylate–dicyandiamide–formaldehyde resin complex and its absorption of rare earth ions
Authors: Su Zhi‐Xing , Zhou Yun‐Bin , Chang Xi‐Jun , Jin Yi , Qi Shang‐Kui
Published: August 2002

Poly(vinyl alcohol) phosphorylate was prepared and its complex with dicyandiamide–formaldehyde resin was used for adsorption and separation of Sm3+, Nd3+, Gd3+, Ho3+, and Er3+ ions. The factors that affect the adsorption and separation of these ions on the polyacid–polybase complex, such as the acidity of the sample solution, adsorption capacity, and conditions of desorption, were investigated by means of spectrophotometry and inductively coupled plasma optical emission spectrometry. IR spectrometry and X‐ray photoelectric spectrometry were used to study the adsorption mechanism, and the probably coordination structure was given. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 962–968, 2002; DOI 10.1002/app.10197
Activation of bifunctional coupling agents in fiberglass/polyethylene composites by electron beam
Authors: Van Dyke J. D. , Gnatowski Marek , Burczyk Andrew
Published: August 2002

Electron beam (EB) radiation was investigated as a means to initiate coupling between the fiberglass and plastic phases in fiberglass/polyethylene plastic composites using two bifunctional compounds, 12‐azido‐1‐diazo‐2‐dodecanone (A) and 1‐diazo‐17‐octadecene‐2‐one (B). Chemical studies reveal that EB radiation has the potential to bind both of these compounds to fiberglass. Fiberglass coated with either A or B shows reduced values of percentage recovery upon exposure to EB, indicating a reaction between these compounds and the glass surface. However, even 400 kGy of radiation was not as effective as a heat treatment for 45 min at 150°C. To test the effectiveness of EB radiation to couple these compounds to polyethylene, fiberglass samples were heat‐treated with compounds A and B, followed by extrusion mixing with polyethylene, and exposure of molded tensile and impact samples to EB radiation. Compound B showed the best overall ability to couple with the polyethylene matrix, but a 400‐kGy dose was necessary to bring about substantial coupling. At 400 kGy, samples containing B showed a 23% improvement in tensile properties and a 30% change in Izod impact. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2579–2594, 2002
Improvement in impact property of continuous glass mat reinforced polypropylene composites
Authors: Zhou Xiaodong , Dai Gance , Lin Qunfang
Published: August 2002

The toughened polypropylene (PP) was obtained by the blending of PP with ethylene‐propylene diene monomer (EPDM). The impact property of continuous glass mat‐reinforced polypropylene was adjusted through three ways: different toughness PPs and their blends were used as matrices, the functionalized polypropylene was added into the matrix to control the interfacial adhesion; the ductile interlayer was introduced at the fiber/matrix interphase by the grafting and crosslinking of rubber chains on fiber surface. The effect of PP toughness, interfacial adhesion, and ductile interlayer on the mechanical properties of composite systems was studied. The impact toughness of GMT increased with increasing the matrix toughness, whereas the flexural strength and modulus decreased. The good interfacial adhesion resulted in the low impact toughness. However, GMT composite with high strength, modulus, and impact toughness could be obtained by the introduction of a ductile interlayer at fiber/matrix interphase. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2680–2688, 2002
Pertraction of cations in a hybrid membrane system containing soluble polymeric ionophores
Authors: Wódzki Romuald , Świątkowski Marek , Kałużyński Krzysztof , Pretula Julia
Published: August 2002

A hybrid membrane system composed of two insoluble cation‐exchange membranes (Nafion) and a liquid membrane in between was studied. A series of organic and aqueous liquid membranes containing soluble polymers as macromolecular ionophores (macroionophores) was prepared and tested. The pertraction (membrane‐transport) characteristics of poly(ethylene glycol) and its ionizable derivatives, including as poly[poly(oxyethylene) phosphate] (PPOEP) and di‐[ω‐methoxy poly(oxyethylene)] phosphate, were measured and are discussed as dependent on the composition and molecular mass of a macroionophore. The liquid membrane composed of PPOEPs dissolved in dichloroethane combined the cation‐exchange properties with neutral coordination functionalities introduced by the poly(oxyethylene) backbone of this ionophore. The overall fluxes, facilitation factors, and the membrane system selectivity were measured in the carrier‐mediated pertraction of transient metal cations (Cu2+, Zn2+, Mn2+, Co2+, and Ni2+). PPOEP could facilitate the pertraction of Zn2+ and Cu2+ over Ni2+ and Co2+. In the case of an aquatic hybrid membrane system, high but nonselective ionic fluxes were observed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 99–109, 2002; DOI 10.1002/app.10263
Hydroxyalkylation of parabanic acid. I. Reactions with formaldehyde
Authors: Zarzyka‐Niemiec Iwona , Lubczak Jacek
Published: August 2002

The results of investigations into the reaction of parabanic acid with formaldehyde at different molar ratios of the reagents are presented. A fast and effective method of synthesis of N,N′‐bis(hydroxymethyl)parabanate was developed. The reaction of parabanic acid with an excess of formaldehyde was analyzed and the structure of the products proposed. Conditions at which the hydroxymethyl derivatives of parabanic acid undergo self‐condensation as well as prospects of using them in subsequent oxyalkylation with oxiranes are specified. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2858–2872, 2002; DOI 10.1002/app.10274
Equivalent processing time analysis of glass transition development in epoxy/carbon fiber composite systems
Authors: Park In‐Kyung , Lee Doo‐Sung , Nam Jae‐Do
Published: August 2002

The cure kinetics and glass transition development of a commercially available epoxy/carbon fiber prepreg system, DMS 2224 (Hexel F584), was investigated by isothermal and dynamic‐heating experiments. The curing kinetics of the model prepreg system exhibited a limited degree of cure as a function of isothermal curing temperatures seemingly due to the rate‐determining diffusion of growing polymer chains. Incorporating the obtained maximum degree of cure to the kinetic model development, the developed kinetic equation accurately described both isothermal and dynamic‐heating behavior of the model prepreg system. The glass transition temperature was also described by a modified DiBeneditto equation as a function of degree of cure. Finally, the equivalent processing time (EPT) was used to investigate the development of glass transition temperature for various curing conditions envisioning the internal stress buildup during curing and cooling stages of epoxy‐based composite processing. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 144–154, 2002; DOI 10.1002/app.10282
Study of the influence of the reaction parameters on the composition of the metallocene‐catalyzed ethylene copolymers using temperature rising elution fractionation and 13C nuclear magnetic resonance
Authors: Barrera Griselda , Galland  , Santos Raquel , Mauler  , Portal Luciana , Silva Da , Liberman Susana , Arli Adilson , Silva Da , Filho  , Quijada Raúl
Published: August 2002

Polyethylene copolymers prepared using the metallocene catalyst rac‐Et[Ind]2ZrCl2 were fractionated by preparative Temperature Rising Elution Fractionation (p‐TREF) and characterized by 13C nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), and gel permeation chromatography (GPC) to study the heterogeneity caused by experimental conditions. Two ethylene–1‐hexene copolymers with different 1‐hexene content and an ethylene–1‐octene copolymer all obtained using low (1.6 bar) ethylene pressure were compared with two ethylene–1‐hexene copolymers with different 1‐hexene content obtained at high ethylene pressure (7.0 bar). Samples obtained at low ethylene pressure and with low 1‐hexene concentration in the reactor presented narrow distributions in composition. Samples prepared with high comonomer concentration in the reactor or with high ethylene pressure showed an heterogeneous composition. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 155–163, 2002; DOI 10.1002/app.10284
Poly(1,3‐disila‐1,3‐diphenyl‐2‐oxaindane)– poly(dimethylsiloxane) block copolymers
Authors: Mukbaniani O. , Matsaberidze M. , Karchkhadze M. , Khananashvili L. , Achelashvili V.
Published: August 2002

The hydrolytic condensation of 1,3‐dichloro‐1,3‐disila‐1,3‐diphenyl‐2‐oxaindane under neutral conditions produced α'ω‐dihydroxy‐1,3‐disila‐1,3‐diphenyl‐2‐oxaindane (polymerization degree ≈ 4). The homofunctional condensation of α'ω‐dihydroxy‐1,3‐disila‐1,3‐diphenyl‐2‐oxaindane in a toluene solution and in the presence of activated carbon was performed, and dihydroxy‐containing oligomers with various degrees of condensation were obtained. Through the heterofunctional condensation of dihydroxy‐containing oligomers with α'ω‐dichlorodimethylsiloxanes in the presence of amines, corresponding block copolymers were obtained. Gel permeation chromatography, differential scanning calorimetry, thermomechanical analysis, thermogravimetry, and wide‐angle roentgenography investigations were carried out. Differential scanning calorimetry and roentgenography studies of the block copolymers showed that their properties were determined by the ratio of the lengths of the flexible and linear poly(dimethylsiloxane) and rigid poly(1,3‐disila‐1,3‐diphenyl‐2‐oxaindane) fragments in the macromolecular chain. At definite values of the lengths of the flexible and rigid fragments, a microheterogeneous structure was observed in the synthesized block copolymers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1409–1417, 2002; DOI 10.1002/app.10335
Phenol‐modified polypropylenes as adhesion promoters in glass fiber–reinforced polypropylene composites
Authors: Eteläaho P. , Järvelä P. , Stenlund B. , Wilén C.‐E. , Nicolas R.
Published: August 2002

This publication is based on research work done on functional phenol‐modified polypropylenes (PPs) as adhesion promoters in glass fiber–reinforced PP composites. The glass fiber roving was first impregnated with different combinations of functional polymers and polypropylene in a melt impregnation die attached to an extruder to obtain prepreg. The prepreg was then tested in many ways both macro‐ and micromechanically. The tests included notched tensile tests, optical and electron microscopy, and DMTA (dynamic mechanical thermal analyzer) and DSC (differential scanning calorimetry) analyses as well as determination of the glass content. The tests were run on prepregs containing pure PP, PP with a commercial adhesion promoter, and PP with a number of functional, mostly phenol‐based, polymers. Also, single‐fiber tests were performed on individual glass fibers to test the level of adhesion with the above‐mentioned material combinations. With these tests it could be seen that some of the phenol‐based functional polymers provided the prepreg with better adhesion between the fibers and the matrix than did the commercial adhesion promoter. Optical and electron microscopy also were used in determining the level of adhesion as well as the deformation and fracture mechanisms of the prepreg. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1203–1213, 2002; DOI 10.1002/app.10441
High solids content emulsions. II. Preparation of seed latices
Authors: Schneider M. , Graillat C. , Guyot A. , McKenna T. F.
Published: August 2002

The preparation of concentrated seed latices for use in bimodal and trimodal formulations is presented in the current work. Various recipes of surfactant and initiator were tested in order to allow us to control the number of particles produced during the nucleation stage. Following this, a semi‐batch feed recipe that combined the use of oil‐soluble initiators and pre‐emulsified monomer was used to produce well‐defined latices having well defined particle size distributions. It was found that the primary concern in maintaining latex stability and favorable viscosity was the reduction of undesirable secondary nucleation. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1897–1915, 2002; DOI 10.1002/app.10512
Effect of mixer resident time on the overall moduli of polymer blends
Authors: Xie Zhimin , Zhang Dinghao , Sheng Jing , Song Kaixu
Published: August 2002

The overall moduli tensor of polymer blends is one of the most important characteristics of microscopic morphology development. This article focused on the analysis of dependence of the moduli on mixer resident time in terms of polypropylene–polystyrene (PP/PS) and polypropylene– polyamide1010 (PP/PA1010) blends. Tensile tests on the PP/PS and PP/PA1010 blends with a series of mixer resident times showed a marked change during the initial mixing stage, which may be due to the evolution of particle size and distribution from inhomogeneous to homogeneous. The two cases of periodic spatial distribution of the identical spherical particles were proposed to model the well‐ dispersed and slightly aggregating morphologies in the steady state. Based on the micromechanical model, the moduli of polymer blends were calculated by incorporating the influences of spatial distribution and Poisson's ratio of dispersed particles. Theoretical results indicated that spatial distribution should have little effect on the overall moduli in the steady state. Analysis of the blend system PP/PA1010 with and without compatibilizing agent showed good agreement between the calculations and experiments. Because the interfacial properties were not taken into account, the model gave an overestimate prediction for immiscible blends, like PP/PS for example. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 307–314, 2002
Morphology and mechanical properties of reactive compatibilized polystyrene/ethylene‐vinyl acetate‐vinyl alcohol blends
Authors: Tang L. W. , Tam K. C. , Yue C. Y. , Hu X. , Lam Y. C. , Li L.
Published: August 2002

A reactive compatibilizer, styrene‐maleic anhydride (SMA) was used to compatibilize the blends of polystyrene (PS) and ethylene‐vinyl acetate‐vinyl alcohol (EVAOH), which was synthesized from ethylene‐vinyl acetate (EVA) using transesterification reaction. The compatibilized blends with different compositions were prepared using a twin‐screw extruder and injection molded into the required test specimens. Morphology of Charpy impact‐fractured surfaces, tensile, and impact properties of the blends were investigated. Fourier‐transform infrared spectroscopy (FTIR) was also applied for specific samples to elucidate the presence of the functional groups reaction necessary for reactive compatibilization. The results of the ternary PS/EVAOH/SMA blends illustrate that the addition of SMA as a compatibilizer slightly reduce the elongation at break. From the impact‐fractured surfaces of the blends, it is evident that the morphology developed sizable pores when SMA was added into the blends. This might be attributed to the residual octanol‐1, produced from the synthesis of EVAOH, as there is a possibility of a reaction between hydroxyl groups in the octanol‐1 and the anhydride groups in the SMA. This disrupted the stability of the morphology and resulted in the decrease in the elongation, and hence, the tensile toughness. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 209–217, 2002
Effects of vibration blending on the subsequent crystallization behavior of polycarbonate/polypropylene blends
Authors: Wang Kejian , Zhou Chixing , Yu Wei
Published: August 2002

The effects of blending in a novel vibration internal mixer on the subsequent multiple crystallization of 70/30 w/w polycarbonate (PC)/polypropylene (PP) were investigated by differential scanning calorimetry, wide‐angle X‐ray diffractogram, and microscopy. The vibration internal mixer was reformed from a conventional internal mixer through parallel superposition of an oscillatory shear on a steady shear. For this polypropylene‐minor phase blend, three possible crystallization peaks were observed. The crystallization behavior was sensitive to the sizes and the size distribution of the dispersed polypropylene droplets. Larger amplitude and/or higher‐frequency vibration produced more small droplets (<2 μm) and increased the number of medium droplets (2–8 μm) as a result of the spatially wider and temporally quicker variation of shear rate. The resulting subsequent low‐temperature crystallization peak became larger and shifted to lower temperature, and the intermediate‐temperature peak became obvious. On the contrary, the coalescence of small droplets, resulting from the heating treatment, weakened the low‐temperature peak but strengthened the intermediate‐temperature peak and rendered the high‐temperature peak to be wider. Mixing at the too high amplitude produced the unstable, partially cocontinuous phase morphology restricting the medium droplets and enlarging the surface area, such that the intermediate‐temperature crystallization peak did not appear. Multiple crystallization was related to phase morphology and the nucleation density as well as surface effects. Double‐fusion endotherms of the PP component were also observed, corresponding to the melting of different forms of polypropylene crystals. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 92–103, 2002
Studies on fibers spun from poly(vinyl alcohol‐b‐acrylonitrile) emulsions prepared by ultrasonic technique. II. Properties of the fibers
Authors: Xiao W. , Xiao L. , Xu K. , Chen K. , Xu X.
Published: August 2002

The moisture content of poly(vinyl alcohol‐b‐acrylonitrile) fibers decreases with an increasing hydrophobic AN content and crystallinity of the fibers; however, the copolymer fiber with 26.94% AN, drawn × 5, and heat‐treated at 200°C has a moisture content value slightly lower than that of commercial PVA fiber, but much higher than that of commercial PAN fiber. The block copolymer fibers have a water‐retention value higher than that of commercial PVA fiber, owing to the presence of voids in these fibers, and have a stronger wicking ability than that of commercial PVA, PAN fibers, and wool and cotton mainly due to the grooved surface and bulk porous morphology of the fibers. The tensile strength of the copolymer fibers with an appropriate AN content are lower than that of commercial PVA fiber, but higher than that of commercial PAN fiber and much higher than that of wool and cotton. The melting temperatures of the copolymer fibers increase with increasing heat‐treatment temperature. The copolymer fibers possess a lower peak cyclizing temperature than that of the PAN fiber and have a higher thermal stability than that of both PVA and PAN fibers. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 989–994, 2001
Kinetic study by differential scanning calorimetry of the bulk copolymerization of 2‐hydroxyethylmethacrylate with ethyleneglycoldimethacrylate
Authors: Ajzenberg N. , Ricard A.
Published: August 2002

This article presents a kinetic study of the copolymerization of 2‐hydroxyethylmethacrylate (HEMA) with ethyleneglycoldimethacrylate (EGDMA). First, the rate constant of decomposition, kd, of azobisisobutyronitrile (AIBN) used to initiate the copolymerization was investigated. Then, the reactivity ratios, r1 and r2, of the monomers (HEMA and EGDMA), and the termination rate constant, kt, were determined. Rate constants were obtained by differential scanning calorimetry (DSC) experiments. The decomposition rate constant of AIBN follows an Arrhenius law in the temperature range 320–400 K. Copolymerizations were carried out in the pans of the DSC apparatus at 353 K. The reactivity ratios, determined after analysis of the mixture composition by gas chromatography, exploitation of the data using the Meyer and Lowry equation, and a numerical method, were found equal to r1 = 0.811 and r2 = 6.548. Also from the reaction rate obtained by DSC, the dependence of the termination rate constant with conversion and temperature has been established. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1220–1228, 2001
Blending poly(methyl methacrylate) and poly(styrene‐co‐acrylonitrile) as composite polymer electrolyte
Authors: Digar Mohanlal , Hung Shiue‐Liang , Wen Ten‐Chin
Published: August 2002

A blend of poly(methyl methacrylate) (PMMA) and poly(styrene‐co‐acrylonitrile) (PSAN) has been evaluated as a composite polymer electrolyte by means of differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy, ac impedance measurements, and linear sweep voltammetry (LSV). The blends show an interaction with the Li+ ions when complexed with lithium perchlorate (LiClO4), which results in an increase in the glass‐transition temperature (Tg) of the blends. The purpose of using PSAN as another component of the blend is to improve the poor mechanical properties of PMMA‐based plasticized electrolytes. The mechanical property is further improved by introducing fumed silica as inert filler, and hence the liquid electrolyte uptake and ionic conductivity of the composite systems are increased. Room‐temperature conductivity of the order of 10−4 S/cm has been achieved for one of the composite electrolytes made from a 1/1 blend of PSAN and PMMA containing 120% liquid electrolyte [1M LiClO4/propylene carbonate (PC)] and 10% fumed silica. These systems also showed good compatibility with Li electrodes and sufficient electrochemical stability for safe operation in Li batteries. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1319–1328, 2001
Transesterifications of poly(bisphenol A carbonate) with aromatic and aliphatic segments in ethylene terephthalate–caprolactone copolyester
Authors: Zhang Zhongping , Luo Xiaolie , Lu Yuchen , Ma Dezhu
Published: August 2002

In this article, transesterification of poly(bisphenol A carbonate) (PC) with a ethylene terephthalate–caprolactone copolyester at a weight ratio 50/50 (TCL50) was investigated by infrared spectroscopy (IR), proton nuclear magnetic resonance spectroscopy (1H‐NMR), and a model compound. The IR and 1H‐NMR results showed that transesterification occurred between PC and ethylene terephthalate (ET) segments in TCL50 and resulted in the formation of bisphenol A–terephthalate ester units as in the annealed blend of PC with the PET homopolyester. By comparison with a model compound, the new signal at 2.55 ppm in the 1H‐NMR spectrum confirmed the appearance of bisphenol A–caprolactone ester units resulting from the exchange reaction of PC with caprolactone (CL) segments. The 1H‐NMR analysis of the transesterification rates revealed that the reactions of PC with aromatic and aliphatic segments in TCL50 proceeded in a random or free manner. In addition, we separately examined the interchange reaction between a PC and poly(ε‐caprolactone) (PCL) homopolyester in an annealed blend. It was found that in the presence of a Ti compound catalyst the predominant reaction was a transesterification rather than a thermooxidative branching reaction. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1558–1565, 2001
Light‐scattering study of poly(hydroxy ester ether) in N,N‐dimethylacetamide solution
Authors: Cao X. , Sessa D. J. , Wolf W. J. , Willett J. L.
Published: August 2002

Static and dynamic light‐scattering techniques were used to study biodegradable thermoplastic poly(hydroxy ester ether) in N,N‐dimethylacetamide (DMAc). A weight‐average molecular weight MW = 6.4 × 104 g/mol, radius of gyration RG = 9.4 nm, second‐virial coefficient A2 = 1.05 × 10−3 mol mL/g2, translational diffusion coefficient D = 1.34 × 10−7 cm2/s, and hydrodynamic radius RH = 8.3 nm are reported. In addition, the effect of H2O on the polymer chain's conformation and architecture in a DMAc/H2O solution is evaluated. Results suggest that H2O makes the mixed solvent poorer as well as promotes polymer chain branching via intramolecular transesterification. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1737–1745, 2001
Preparation of polyethylene oxide/LixV2‐δO4‐δ nanocomposites
Authors: Xiao Y. , Hu K. A. , Yu Q. C. , Wu R. J.
Published: August 2002

Polyethylene oxide (PEO)/LixV2‐δO4‐δ nanocomposites were prepared in aqueous solution. Characterization of the nanocomposites using thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), powder X‐ray diffraction (XRD), and Fourier transform infrared spectrum (FTIR) shows that polymer chains intercalate inorganic host lamella and exhibit lattice expansion along the stacking direction of 4.2 Å. A possible model for the structure of the nanocomposite is also provided. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2162–2166, 2001
Three‐dimensional dielectric characterization of polymer films
Authors: Patel Kaushal S. , Kohl Paul A. , Bidstrup‐Allen Sue Ann
Published: August 2002

Polymer films are widely used in electronic packaging applications due to their low dielectric constant and ease of fabrication. These films often exhibit anisotropic electrical and thermomechanical properties, due to orientation of polymer chains, which need to be evaluated for performance and reliability modeling of electronic packages. This article presents a dual‐capacitor technique to measure the anisotropic dielectric permittivities of such films. Results are reported for in situ measurements for several spin‐coated polymeric films, some of which exhibit different permittivities in the in‐plane (x and y) and the through‐plane (z) directions (transversely isotropic), and free‐standing liquid crystalline Vectran films which exhibit orthotropic permittivities. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2328–2334, 2001
Effect of yielding on the viscoelastic response of amorphous glassy polymers
Authors: Drozdov Aleksey D.
Published: August 2002

Constitutive equations are derived for the nonlinear viscoelastic behavior of amorphous glassy polymers. The model is based on the theory of cooperative relaxation in a version of the trapping concept. Stress–strain relations are applied to fit experimental data for polycarbonate in the sub‐yield and post‐yield regions. Fair agreement is demonstrated between observations and results of numerical simulation. It is revealed that yielding causes substantial changes in the energy landscape of amorphous polymers. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2383–2393, 2001
Synthesis and characterization of maleinized‐silylated low molecular weight guayule rubber (MASiGR)
Authors: Thames Shelby F. , Gupta Sandhya
Published: August 2002

Maleinization followed by silylation of low molecular weight guayule rubber was accomplished for the first time via a two‐step process. Maleinization was first effected by grafting maleic anhydride onto guayule rubber under the influence of benzoyl peroxide catalyst to give maleinized guayule rubber (MAGR). The maleinized rubber was then further derivatized via hydrosilylation with dichloromethyl silane and chloroplatinic acid (Speier's catalyst) to give maleinized‐silylated guayule rubber (MASiGR). The silylated polymer (MASiGR) was further functionalized by reaction with ethanol or aqueous ammonia to produce ethoxysilane and silanol moieties, respectively. The products were characterized by Fourier transform infrared spectroscopy (FTIR), 1H‐, 13C‐, and 29Si‐ nuclear magnetic resonance spectroscopy (NMR). © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 754–761, 2001
Creating a macromolecular receptor by affinity imprinting
Authors: Vaidya A. A. , Lele B. S. , Kulkarni M. G. , Mashelkar R. A.
Published: August 2002

A molecularly imprinted polymeric receptor for trypsin was synthesized by employing a novel technique that is a combination of affinity separation and molecular imprinting. An enzyme–inhibitor complex of trypsin and N‐acryloyl para‐aminobenzamidine was polymerized with acrylamide and N,N'‐methylene bis‐acrylamide. Template trypsin was extracted out to obtain an affinity‐imprinted polymer. Control experiments were performed to demonstrate the synergistic affinity‐imprinting effect. The percentage of crosslinker used was the crucial factor in determining the imprinting efficacy of the polymers. Imprinted polymer containing 50% crosslinker exhibited a linear Scatchard plot. Unlike non‐imprinted gel, the receptor exhibited almost exclusive recognition of trypsin in an individual batch experiment as well as from a mixture of trypsin and chymotrypsin. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1075–1083, 2001
Long‐term mechanical and viscoelastic behavior of constitutive polymeric materials used for magnetic tapes
Authors: Weick Brian L. , Bhushan Bharat
Published: August 2002

Creep‐compliance behavior of specially prepared magnetic tape materials was measured at elevated temperature levels to facilitate the use of a time–temperature superposition (TTS) process. This TTS process allowed for the construction of master curves at a reference temperature of 30°C, which were used to predict the long‐term viscoelastic behavior of the magnetic particle (MP) and metal‐evaporated (ME) tapes used in the study. The specially prepared samples allowed for the use of a rule of mixtures technique to determine the long‐term creep compliance of the front coat and back coat used for the magnetic tapes. To test the validity of this procedure, the front coat, substrate, and back coat data determined through separate experiments were used to calculate creep compliances of simulated tapes. These calculated creep‐compliance curves were then compared to measured data for the actual magnetic tapes. After determination and validation of the front coat, substrate, and back coat creep‐compliance data sets, they were used to determine strain distributions when the tapes are stored in a reel. Strain distributions were calculated for two cases, which reflect how tapes are stored in different drives: (1) the front coat (magnetic + nonmagnetic layer) is oriented away from the hub, and (2) the front coat is oriented toward the hub. Results showed that strain in the critical front coat of a tape is lower if it is stored with the front coat oriented toward the hub. In addition, the use of the creep‐compliance data showed that the MP tape front coat is more susceptible to creep than the ME tape front coat. The strain distributions in future magnetic tapes were also simulated by reducing the thickness and compliance of the layers. Results showed the importance of using lower compliance front coat, substrate, and back coat materials if thinner tapes are to be developed to increase the volume of information that can be stored in a magnetic tape reel. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1142–1160, 2001
Separation of Tc‐99m by means of radiation‐grafted membranes
Authors: Kamal H. , Hegazy El‐Sayed A. , El‐Adham K. , Geleel M. Abdel
Published: August 2002

The characterization and possibility of the practical use of different polymeric materials for the purpose of radioactive isotope separation from their wastes were studied. The influence of chemical treatment on the chelation or adsorption capacity at 25 °C was investigated. The equilibrium swelling of these polymers in distilled water at room temperature and the effect of solvent composition on the graft yield were also explored. In this study, the mechanical, chemical resistance and other properties for the grafted, untreated, and treated membranes were investigated. The performance of the membranes was studied as a function of time and degree of grafting. The effects of chemical treatment on the initial activity and separation of Tc‐99m have also been examined. The base polymer and degree of grafting have great influence on the Tc uptake. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1207–1215, 2001
Synthesis and properties of high oil‐absorptive network polymer 4‐tert‐butylstyrene–SBR–divinylbenzene
Authors: Zhou Mei Hua , Ha Chang‐Sik , Cho Won‐Jei
Published: August 2002

4‐tert‐Butylstyrene–SBR–divinylbenzene (PBSD) was prepared by the graft crosslinking polymerization of 4‐tert‐butylstyrene (tBS) and divinylbenzene (DVB) onto unvulcanized SBR in the solution process using BPO as an initiator. The effects of reaction conditions, such as, solvent amount, SBR content, mol ratio of DVB to tBS, initiator concentration, reaction temperature, and reaction time on conversion, grafting efficiency, and gel fraction were examined. In present reaction system, a solvent amount 15.0 mL/g is the threshold of the gelation process. The oil absorbency was evaluated by the ASTM (F726‐81) method. The swelling rates, light resistance, and tensile strength of PBSD were investigated. It was found that the tensile strength is considerably better than that of 4‐tert‐butylstyrene–EPDM–divinylbenzene polymer (PBED). The highest oil absorbency of crosslinked PBSD was 57.76 g/g, and the largest swelling kinetic constant was 102.09 × 10−2 h−1. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1277–1285, 2001
Identification of deformation behavior in high‐thermal‐resistant poly(acrylonitrile‐butadiene‐styrene) (ABS)
Authors: Jar P.‐Y. Ben , Lee R. , Creagh D. C. , Konishi K. , Shinmura T.
Published: August 2002

Deformation mechanisms in postfractured high‐thermal‐resistant poly(acrylonitrile‐butadiene‐styrene) (ABS) were investigated using transmission electron microscopy (TEM) and small‐angle X‐ray scattering (SAXS). Although crazes were clearly identified by TEM, they were not detectable by SAXS. This was possibly due to a short distance between sample and imaging plate in the SAXS set‐up and invisibility of craze fibril scattering from the postfractured samples. A rhomboid‐shaped SAXS pattern was obtained from ABS samples with high ductility but with no crazes shown in the TEM micrographs. It is believed that the rhomboid‐shaped SAXS pattern was generated from matrix shear yielding. The results show that a combination of TEM and SAXS enable us to distinguish crazing and shear yielding in the postfractured ABS. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1316–1321, 2001
Construction of cell‐compatible layer and culture of human umbilical vascular endothelial cells on porous polystyrene membranes
Authors: Gao Changyou , Li An , Yi Xiaosu , Shen Jiacong
Published: August 2002

Porous polystyrene (PS) membranes with pore sizes ranged from nanometer scale to several decades' micrometers were fabricated by the thermally induced phase‐separation technique, and were characterized by scanning electron microscopy (SEM). Oxidation of PS membranes by concentrated sulfuric acid induced a decrease of the carbon amount on the membrane surfaces accompanying with an increase of the oxygen amount. The hydrophilic surfaces thus constructed proved quite effective to promote endothelial cell adhesion and growth. After culturing for 4 days, a confluent endothelial cells (ECs) layer was observed on nonporous PS membrane treated previously with sulfuric acid for 15 min at 28.5°C. The observation under SEM showed that ECs on the PS membrane surfaces at the fourth day were inversely proportional to the pore size: the smaller the pore size, the larger the amount of ECs on the membrane surfaces. It is supposed that the existence of pores on the membrane surface might generate some disadvantageous resistance to the spreading of cells. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3523–3529, 2001
Preparation and characterization of copolymers containing (+)‐bornyl methacrylate and their racemate for positive‐tone photoresist
Authors: Liu Jui‐Hsiang , Shih Jen‐Chieh , Shih Chih‐Hung , Chen Wei‐Ting
Published: August 2002

This study investigated the chemical behavior of polymers bearing cycloaliphatic bornyl units along with the steric difference of the chiral (+)‐bornyl methacrylate [(+)‐BMA] and racemic (±)‐BMA, expressed in the physical properties of the copolymers and the resist characteristics. To do this, a series of copolymers containing (+)‐bornyl methacrylate [(+)‐BMA] and (±)‐BMA] units was synthesized. Comonomers of tert‐butyl methacrylate (TBMA), methyl methacrylate (MMA), and maleic anhydride (MA) were used. The thermogravimetric curves, glass‐transition temperature (Tg), and molecular weight (MW) of the copolymers were evaluated. Exposure characteristics of chemical‐amplified positive photoresists comprising various copolymers were investigated. It was found that copolymers bearing (±)‐BMA have higher Tg and better thermostability than those of copolymers containing (+)‐BMA units. The copolymers with (±)‐BMA units, however, revealed an inert photochemical behavior on the positive‐tone photoresist. The patterning properties of the positive photoresist, composed of copolymers bearing (+)‐BMA and (±)‐BMA, and the photoacid generator (PAG) were also investigated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3538–3544, 2001
Copolymerization of carbon monoxide and styrene with the Nd(III)–Cu(II) catalyst
Authors: Yao Fanglian , Deng Liandong , Men Jihong , Feng Yakai , Sun Jingwu
Published: August 2002

In this article, the linear alternating copolymer of carbon monoxide and styrene was obtained using the Nd(III)–Cu(II) catalyst. It was found that the introducing order of the catalyst components can affect the catalytic activity, and the pre‐prepared catalyst had higher catalytic activity than the in situ catalyst. The promoting effect of copper acetate on the catalytic activity was also investigated. The structure of the copolymer was characterized by means of IR, 1H‐NMR, 13C‐NMR, WXRD, and EA methods. The thermal decomposition properties were checked by the way of TGA. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 8–13, 2001
Anionic block copolymerization of cyclotetrasiloxanes initiated by 4,4'‐bis(dimethyllithiioxylsilyl)diphenyl ether
Authors: Liu Zonglin , Wu Chunlei , Hu Wenjun
Published: August 2002

The anionic copolymerization of cyclotetrasiloxanes initiated by 4,4′‐bis(dimethyllithiioxylsilyl)diphenyl ether (BDMOLiPE) was carried out for the preparation of poly(diphenyl‐dimethyl‐diphenyl)siloxane block copolymers (PMP). To reduce redistribution reaction, the lithium‐based dianionic initiator (BDMOLiPE) was first used for the copolymerization of the cyclotetrasiloxane monomers without solvent, with dimethyl formamide (DMF) as a promotor. The cyclotetrasiloxanes used involved octamethylcyclotetrasiloxane (D4), octaphenylcyclotetrasiloxane (P4), and tetramethyl‐tetravinylcyclotetrasiloxane (V4). The copolymers obtained were characterized withproton nuclear magnetic resonance spectroscopy, infrared spectroscopy, intrinsic viscosity([η]) determination, transmission electron microscopy, and wide‐angle X‐ray diffraction analysis. The results illustrate that the products should belong to block copolymers but not be too perfect because the block copolymers were scrambled to a certain extent during the copolymerization process. However, we can approximately express them as PMP and PMVP, according to the different order of the feeding in raw materials. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1203–1210, 2001
Microstructure of HTPB‐based polyurethane membranes and explanation of their low O2/N2 selectivity
Authors: Ruaan Ruoh‐Chyu , Ma Wen‐Chung , Chen Shih‐Hsiung , Lai Juin‐Yih
Published: August 2002

Polyurethane (PU) membranes usually have high gas permeability but low selectivity. It was supposed that an increase of the hard‐segment content in PU membranes would enhance the selectivity since the hard segment has a higher oxygen affinity and could reduce the chain mobility. However, an attempt to increase the O2/N2 selectivity by increasing the hard‐segment content failed. It was found that increase of the hard‐segment content did increase the gas solubility but the solubility ratio of oxygen to nitrogen was not increased. Increase of the hard‐segment content also reduced the permeabilities of both oxygen and nitrogen, but no improvement of the O2/N2 diffusivity ratio was observed. The microstructure of polybutadiene‐containing PU was examined by DSC and FTIR measurements. It was found that hydrogen bonding between hard segments was the cause of the failure of selectivity improvement. Avoiding the formation of hydrogen bonds between the hard segments is the key for a successful improvement of the O2/N2 selectivity of the PU membranes. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1307–1314, 2001
Preparation and swelling properties of crosslinked sodium polyacrylate
Authors: Liu Mingzhu , Guo Tianhua
Published: August 2002

Crosslinked sodium polyacrylate as a superabsorbent was prepared by inverse suspension polymerization with cyclohexane as the continuous phase and sorbite anhydride monostearic acid ester (span‐80) as the dispersant. The crosslinking degree was regulated by NaOH. The distilled water absorbency (WA) of the polymer gel was about 700 times its own weight if the gel was allowed to swell at room temperature for 24 h. WA under various conditions, such as varying pH, temperature, reaction time, neutralization, and cyclohexane concentration, was investigated and optimized. Our results revealed that the optimal reaction conditions were 55°C, 25‐min reaction time, 85% neutralization, and a 7:1 (v/v) cyclohexane/monomer ratio. Our results also showed that such synthesized polymer gels have a high WA and a good water‐retention ability under different pressures. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1515–1520, 2001