bluuebunny/crossref_metadata_2025 huggingface dataset:
Hydrophilic drug release from bioerodible polyanhydride microspheres
Authors: Vasheghani‐Farahani Ebrahim , Khorram Mohammad
Published: August 2002

The present investigation was carried out to develop bioerodible drug delivery systems. Copolymers of fumaric anhydride and isophthalic anhydride were synthesized by melt polycondensation. To synthesize a copolymer with known composition, soluble in common organic solvents, a prepolymer of each monomer was first prepared. Copolymers were synthesized by mixing two prepolymers followed by melt polycondensation of the resulting mixture with a specific ratio of each prepolymer. Microspheres loaded with theophylline and diltiazem hydrochloride (DHC) were obtained using the solvent removal method in an oil‐in ‐oil (O/O) emulsion system. The size of the drug loaded microspheres was less than 75 μm, which is suitable for subcutaneous or intramuscular injection. DHC was incorporated in a polymeric carrier better than theophylline because of its solubility in chloroform and dichloromethane. In vitro release of two drugs in the phosphate buffer solution indicated that the release profile of DHC was closer to a zero‐order kinetic profile compared with theophylline. Finally, drug release data was compared with three semiempirical models. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1457–1464, 2002
Novel polymer–ceramic nanocomposite based on high dielectric constant epoxy formula for embedded capacitor application
Authors: Rao Yang , Ogitani S. , Kohl Paul , Wong C. P.
Published: August 2002

Embedded capacitor technology can increase silicon packing efficiency, improve electrical performance, and reduce assembly cost compared with traditional discrete capacitor technology. Developing a suitable material that satisfies electrical, reliability, and processing requirements is one of the major challenges of incorporating capacitors into a printed wiring board (PWB). Polymer–ceramic composites have been of great interest as embedded capacitor material because they combine the processability of polymers with the high dielectric constant of ceramics. A novel nanostructure polymer–ceramic composite with a very high dielectric constant (εr ∼110, a new record for the highest reported εr value of a nanocomposite) was developed in this work. A high dielectric constant is obtained by increasing the dielectric constant of the epoxy matrix (εr >6) and using the combination of lead magnesium niobate–lead titanate (PMN–PT)/BaTiO3 as the ceramic filler. This nanocomposite has a low curing temperature (<200°C); thus, it is multichip‐module laminate (MCM‐L) process‐compatible. An embedded capacitor prototype with a capacitance density of 50 nF/cm2 was manufactured using this nanocomposite and spin‐coating technology. The effect of the composite microstructure on the effective dielectric constant was studied. This novel nanocomposite can be used for integral capacitors in PWBs. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1084–1090, 2002
Diffusion of electrolytes in hydrolyzable glassy polymers: Acetic acid in poly(vinyl acetate), poly(vinyl alcohol), and polyesters
Authors: Polishchuk A. Ya. , Valente A. J. M. , Camino G. , Luda M. P. , Madyuskin N. N. , Lobo V. M. M. , Zaikov G. E. , Revellino M.
Published: August 2002

Engineering materials containing poly(vinyl acetate) (PVAc) as the key component undergo hydrolytic degradation, which must be minimized or, at least, controlled. To characterize PVAc hydrolysis quantitatively, the diffusion of acetic acid (HAc) in PVAc, poly(vinyl alcohol) (PVA), unsaturated polyester (UPE), and a UPE/PVAc blend was studied in detail. The permeability cell earlier developed by the authors was modified here to reduce experimental error. As the diffusion and solubility coefficients of water and HAc in the above materials were measured at different temperatures, a mathematical model was developed, which takes proper account of the combined water and HAc diffusion in PVAc undergoing partial hydrolysis. The model was further validated by the experimental data obtained at 70°C for UPE/PVAc film, simulating a matrix of sheet‐molding compounds composite materials. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1157–1166, 2002
Preparation, characterization, and behavior of cellulose–titanium(IV) oxide modified with organosilicone
Authors: Meng Ling‐Zhi , Du Chuan‐Qing , Chen Yuan‐Yin , He Yong‐Bing
Published: August 2002

Cellulose–titanium(IV) oxide modified with organosilicone (CTSN) was prepared by a reaction of cellulose powder with titanic chloride, followed by a reaction with 4‐aza‐6‐aminohexyl triethoxysilane, and was characterized by infrared spectroscopy, scanning electron microscopy (SEM), and thermogravimetric analysis. An SEM image of titanium(IV) oxide‐coated cellulose and a Ti mapping image showed that titanium oxide was well dispersed on the cellulose surface. Titanium and silicon mapping images of CTSN, obtained with SEM, indicated that both oxides were uniformly dispersed on the cellulose surface. The atomic ratio of Ti to Si was obtained with X‐ray energy spectral composition analysis. The adsorption behavior of CTSN toward Hg(II), Cu(II), Pb(II), Fe(III), and Cr(III) ions in aqueous solutions was determined. The adsorption behavior of CTSN toward human serum protein was preliminarily examined. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 61–66, 2002; DOI 10.1002/app.10188
In‐line and in situ monitoring of semi‐batch emulsion copolymerizations using near‐infrared spectroscopy
Authors: Vieira Raphael A. M. , Sayer Claudia , Lima Enrique L. , Pinto José Carlos
Published: August 2002

This article shows that near‐infrared spectroscopy (NIRS) can be used efficiently for the simultaneous in‐line and in situ monitoring of monomer (methyl methacrylate, MMA, and butyl acrylate, BuA) and polymer concentrations in the reaction medium during seeded semibatch emulsion copolymerizations. A series of actual reaction experiments was planned to allow the proper obtainment and selection of calibrating samples. Partial least squares (PLS) was used to build three independent calibration equations in the range of 1100–1900 nm, which were used to successfully monitor some disturbed reactions in‐line. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2670–2682, 2002
Thermal behavior of polyaniline films and polyaniline–polystyrene blends
Authors: Jousseaume V. , Morsli M. , Bonnet A.
Published: August 2002

In this article, a study of the thermal behavior of polyaniline films and polyaniline–polystyrene blends is presented. Transport measurements (electrical conductivity and thermoelectric power) at high temperature and thermogravimetric analysis show that an irreversible degradation is observed near 450 K for films doped with DiOHP and near 500 K for films doped with CSA. In both cases, the thermoelectric power is the most sensitive parameter to electrical degradation during the heating of conducting films. Electrical conductivity measurements during heating–cooling cycles show a diminution of the room temperature conductivity after evaporation of the solvent (water, m‐cresol). A model of cluster with a variable diameter allows interpreting this phenomenon by assuming the existence of a sensitive frontier to the solvent at the periphery of conducting clusters. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1848–1855, 2002; DOI 10.1002/app.10468
Preparation and properties of aromatic polyimides based on 4,4′‐(2,2,2‐trifluoro‐1‐phenylethylidene)diphthalic anhydride
Authors: Lee Dong‐Ho , Koo Seung‐Young , Lee Hyung‐Seok , Kim Woo Sik , Min Kyung Eun , Park Lee Soon , Seo Kwan Ho , Kang Inn Kyu , Choi Heung‐Jin
Published: August 2002

Aromatic polyimides were synthesized from aromatic carboxylic acid dianhydrides, 2,2‐bis(3,4‐dicarboxyphenyl)hexafluoropropane dianhydride (6FDA), 4,4′‐(2,2,2‐trifluoro‐1‐phenylethylidene)diphthalic anhydride (3FDA), and pyromellitic dianhydride (PMDA), with four typical aromatic diamines. These included polyimide (PI) from 2,2‐bis(4‐aminophenyl)hexafluoropropane (4BDAP) by two‐step procedures; amidation to polyamic acid (PAA), followed by thermal imidization of PAA. The chemical and physical properties of the newly prepared polyimides were compared in terms of their chemical structures, inherent viscosity, thermal property, transmission, dielectric constant, UV cutoff, water absorption, and refractive index. PIs 3FDA/4BDAP and 6FDA/4BDAP were soluble in common organic solvents, whereas others were not. In particular, it was found that the solubility was dependent on the temperature of imidization. The chemical and physical properties of the newly prepared polyimides derived from 3FDA were similar to the polyimides derived from 6FDA. The solubility of polyimide containing an ether functional group in the dianhydride moiety was better than that of the ether functional group in the diamine moiety. The polymers with ether linkage in dianhydride moiety exhibited lower glass transition temperature than their functionality‐reversed analogous polymers with ether linkage in diamine moiety. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 38–44, 2002
Copolymerization of propene with phenylnorbornene using ansa‐bridged metallocene catalysts
Authors: Aitola Erkki , Repo Timo , Bergström Christer , Leskelä Markku
Published: August 2002

Propene was copolymerized with phenylnorbornene using methylaluminumoxane (MAO)‐activated metallocene dichlorides exhibiting different symmetry: C2‐Symmetric rac‐ethylenebis(1‐ indenyl)zirconium dichloride (1), rac‐ dimethylsilylbis(1‐indenyl)zirconium dichloride (2), rac‐ethylenebis(1‐indenyl)hafnium dichloride (6), Cs‐symmetric isopropylidene(cyclopentadienyl‐9‐fluorenyl)zirconium dichloride (3), meso‐ethylenebis(1‐indenyl)zirconium dichloride (4), and C1‐symmetric ethylene(1‐ fluorenyl‐1‐phenyl‐2‐indenyl)zirconium dichloride (5) were chosen to evaluate the influence of the symmetry in copolymerization reactions. Experiments were done as batch polymerizations to produce homogeneous copolymers. By this setup, blend formation was avoided. The copolymers were characterized by NMR, GPC, and DSC. Catalysts 1 and 2 were the most active to copolymerize random, amorphous, copolymers with good activity. Cs‐symmetric, 3, showed decreased activity compared with 1 and 2 and produced a bimodal copolymer. Catalyst 4 showed even lower activity than that of 3. The activity of the hafnium complex 6, which produced a semicrystalline polymer with a high molecular weight (116,000 g/mol) was 320 kg/mol. Catalyst 1 produced the highest comonomer content (42%) in the copolymers measured by NMR. The least active catalyst was 5 (phenyl croup in the bridge), producing only 290 kg copolymer per mole of catalyst. All polymers had elevated glass transition temperatures compared to polypropylene. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2743–2752, 2002
Thermodynamics of surface self‐developing structure formation on polyamide films under ultraviolet irradiation
Authors: Rebouillat Serge , Lavielle Lisette , Wilmet Sophie
Published: August 2002

Polyamide terpolymer films can be obtained by the evaporation of a solvent–terpolymer–photoinitiator mixture on a glass plate. Through ultraviolet (UV) irradiation, self‐developing properties are observed. The nuclear magnetic resonance (NMR) study of the photochemical reaction involved in such a process permits us to propose a mechanism with a diffusion of solvent in the irradiated areas. The thermodynamics of irreversible process have been applied to the analysis of such a system behavior, and an analysis of the stability of the system resulting from its residual solvent content has been made. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 645–653, 2002
Syntheses of acrylate core/shell imbiber beads by seeded suspension copolymerization and one‐stage copolymerization for solvent absorption–desorption
Authors: Kiatkamjornwong Suda , Akkarakittimongkol Pranut , Omi Shinzo
Published: August 2002

Seeded suspension copolymerization or a one‐stage copolymerization was used to synthesize acrylate core/shell imbiber beads. A two‐stage polymerization technique was used for seeded suspension polymerization. The seed particles for poly(methyl acrylate) or poly(2‐ethylhexyl acrylate) were synthesized first in a mixed solvent of toluene/isooctane containing the ethylene glycol dimethacrylate (EGDMA) crosslinking agent. These beads were swollen in styrene‐EGDMA‐BPO (benzoyl peroxide) and then polymerized in the aqueous phase to produce the polystyrene (PS) shell. The one‐stage copolymerization was carried out in toluene/isooctane containing methyl methacrylate (MMA), styrene (St), EGDMA, and BPO at 75°C for 10 h to give a core/shell copolymer of St‐MMA morphology. The appearance of core/shell imbiber beads prepared from these two techniques varied from monomer to monomer. This article describes the preparation, characterization, and application of the core/shell beads for organic solvent absorption/desorption. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 670–682, 2002
Phase‐separated polymer blends: Complementary studies between scanning electron microscopy, epifluorescence microscopy, and fluorescence microspectroscopy
Authors: Granados E. G. , González‐Benito J. , Baselga J. , Dibbern‐Brunelli D. , Atvars T. D. Z. , Esteban I. , Piérola I. F.
Published: August 2002

In this work a morphological description of poly(vinyl alcohol) (PVA)/poly(vinyl acetate) (PVAc) incompatible blends was carried out combining scanning electron microscopy, epifluorescence microscopy, and fluorescence microspectroscopy, and using anthracene and fluorescein probes dissolved in the polymer blends. Because the blends were prepared by casting from a water/ethanol solution over a polyethylene surface, two topologically different faces were formed and analysed: blend/air and blend/support faces. Droplets in matrix morphologies were observed for any composition here studied and sample annealing resulted in the coalescence of domains. Fluorescence micro‐spectroscopy of several parts of the material revealed that the dye distribution over the domain‐matrix interface is different of the internal or external parts of each domain and it is indicative of the interpenetration of both polymers at the interface region. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 949–955, 2001
Nitro derivatives of PEEK‐WC
Authors: Trotta Francesco , Drioli Enrico , Gordano Amalia
Published: August 2002

Nitrated poly(oxa‐p‐phenylene‐3,3‐phthalido‐p‐phenylene‐oxa‐p‐phenylene‐ oxy‐phenylene) (PEEK‐WC) with various average degrees of substitution was obtained by reaction with several nitrating agents. By working under controlled reaction conditions, little degradation of the parent polymer is observed. The nitro derivatives of PEEK‐WC show a high thermal stability, and are able to form membranes by means of phase inversion technique. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1037–1045, 2001
Preparation of water‐swollen hydrogel membranes for gas separation
Authors: Park You‐In , Lee Kew‐Ho
Published: August 2002

Water‐swollen hydrogel (WSH) membranes for gas separation were prepared by the dip‐coating of asymmetric porous polyetherimide (PEI) membrane supports with poly(vinyl alcohol) (PVA)–glutaraldehyde (GA), followed by the crosslinking of the active layer by a solution method. Crosslinked PVA/GA film of different blend compositions (PVA/GA = 1/0.04, 0.06, 0.08, 0.10, 0.12 mol %) were characterized by differential scanning calorimetry (DSC) and their water‐swelling ratio. The swelling behavior of PVA/GA films of different blend compositions was dependent on the crosslinking density and chemical functional groups created by the reaction between PVA and GA, such as the acetal group, ether linkage, and unreacted pendent aldehydes in PVA. The permeation performances of the membranes swollen by the water vapor contained in a feed gas were investigated. The behavior of gas permeation through a WSH membrane was parallel to the swelling behavior of the PVA/GA film in water. The permeation rate of carbon dioxide through the WSH membranes was 105 (cm3 cm−2 s−1 cmHg) and a CO2/N2 separation factor was about 80 at room temperature. The effect of the additive (potassium bicarbonate, KHCO3) and catalyst (sodium arsenite, NaASO2) on the permeation of gases through these WSH membranes was also studied. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1785–1791, 2001
Effect of linear comonomers on the rate of crystallization of copolyesters
Authors: Connor Daniel M. , Allen Scott D. , Collard David M. , Liotta Charles L. , Schiraldi David A.
Published: August 2002

Small amounts of dimethyl‐4,4′‐biphenyldicarboxylate, 2,7‐dimethyl‐4,5,9,10‐tetrahydropyrenedicarboxylate, and dimethyl‐2,7‐pyrenedicarboxylate have been copolymerized into poly(ethylene) terephthalate (PET). The thermal transitions of the copolymers have been characterized, and the crystallization rates have been measured isothermally. Avrami analysis indicates that all the copolymers crystallized at a slower rate than that of the PET homopolymer. Addition of perylene to the copolymers containing pyrene enhanced the rate of crystallization, which could be the consequence of stacked arene assemblies serving as templates for crystal formation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2696–2704, 2001
Styrene‐ethylene/butylene‐styrene blends for improved constrained‐layer damping
Authors: Öborn Jonas , Bertilsson Hans , Rigdahl Mikael
Published: August 2002

The influence on the adhesion to some metal surfaces and the damping properties of various modified styrene‐ethylene/butylene‐styrene (SEBS) materials was evaluated. Modification of the different phases of the SEBS with resins was shown to have a large effect on the damping properties of the polymers, which were evaluated by dynamic mechanical analysis (DMA). A small amount of maleic anhydride grafted onto the EB block was found to lead to a significant improvement in the adhesion of the polymer to some metal surfaces without affecting the damping properties of the polymers. The results of the DMA tests on the polymers were used to calculate the composite loss factor (CLF) for a steel laminate, which consisted of two steel plates with a polymeric layer in between, according to the theory proposed by Ross, Ungar, and Kerwin. The calculated results were compared with the measured CLFs determined in vibrating beam tests (VBTs). The agreement between the calculated and measured values was quite fair, provided that the DMA values used for the calculations were recalculated to the actual higher frequencies used in the VBTs, using the time–temperature superposition principle. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2865–2876, 2001
Polymerization of maleic acid and itaconic acid studied by FT‐Raman spectroscopy
Authors: Yang Charles Q. , Gu Xiaohong
Published: August 2002

In this research, we used a new redox free radical initiation system consisting of potassium persulfate (K2S2O8) and sodium hypophosphite (NaH2PO2). In the presence of NaH2PO2, the thermal decomposition of K2S2O8 is accelerated, and the temperature required for the formation of free radical is reduced. We polymerized maleic acid (MA) using the K2S2O8/NaH2PO2 initiation system in an aqueous solution, and monitored the polymerization process with FT‐Raman spectroscopy. The Raman spectroscopy data indicate the formation of a saturated carboxylic acid with the disappearance of the characteristic bands of MA as the thermal decomposition of K2S2O8 progresses, thus indicating the formation of poly(maleic acid) (PMA). We also found that itaconic acid (IA) polymerizes in the presence of the new initiation system. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 223–228, 2001
Hollow fiber formation using Lewis acid : Base complex in the polymer solution
Authors: Pereira C. C. , Souza J. N. M. , Nobrega R. , Borges C. P.
Published: August 2002

In the present work, hollow fiber formation was investigated by using Lewis acid : base complexes in the polymer solution. The studied systems consisted of poly(ether sulfone); N‐methyl‐2‐pyrrolidone (NMP) as solvent and Lewis base, and acetic, propionic, n‐caproic, and adipic acids as additives and Lewis acids. Bore liquid was formed by water/NMP solutions, as well as vaseline; whereas water was used as external precipitation bath. The spinneret and precipitation bath distance (i.e., air gap) also varied. The membranes were characterized by scanning electron microscopy and pure gas permeation tests. The influence of the complex dissociation rate was observed mainly when a reduction to water inflow from the bore liquid to the polymer solution occurred, because in this case, dissociation rate was inhibited. Therefore, stability was favored in the sublayer for a longer period, allowing macrovoid formation. These results are also evidenced by the permeability coefficients, which increased as fast as the polymer solution reaches water (i.e., the kinetics of precipitation was accelerated). © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 908–917, 2001
New synthetic method for soluble starlike C60‐bonding polymers
Authors: He Ji‐Dong , Wang Juan , Li Si‐Dong , Cheung Man Ken
Published: August 2002

Novel starlike C60‐bonding polymers were synthesized by using the iniferter technique. The fullerene C60 with pendent N,N‐diethyldithiocarbamate groups (C60–SR) was used as polyfunctional photoiniferter. The effects of UV‐irradiation time and ambient temperature on the molecular weight of polymer were investigated. The photopolymerization with C60–SR proceeded via a living‐radical mechanism, and gave soluble polyfunctional polymers (photoiniferters). Multiple polymer arms were attached to the C60 core and the polymers obtained by C60–SR could also be used as excellent crosslinking agents. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1286–1290, 2001
The forced gas sweeping process for semibatch melt polycondensation of poly(ethylene terephthalate)
Authors: Woo Boogon , Choi Kyu Yong , Goranov Konstantin
Published: August 2002

The experimental and modeling studies are presented on the melt polycondensation of poly(ethylene terephthalate) by a gas sweeping process. In this process, low molecular weight prepolymer is polymerized to a higher molecular weight polymer in a molten state at ambient pressure as ethylene glycol is removed by nitrogen gas bubbles injected directly to the polymer melt through a metal tube. In the temperature range of 260–280°C, the rate of polymerization by the gas sweeping process is quite comparable to that of conventional high vacuum process. The effects of nitrogen gas flow rate and reaction temperature on polymerization rate and polymer molecular weight were investigated. Polymer molecular weight increases with an increase in gas flow rate up to certain limits. A dynamic mass transfer–reaction model has been developed, and the agreement between experimental data and model simulations was quite satisfactory. The effect of ethylene glycol bubble nucleation on the polymerization has also been investigated. It was observed that the presence of nucleated ethylene glycol bubbles induced by the bulk motion of polymer melt has negligible impact on the polymerization rate and polymer molecular weight. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1388–1400, 2001
Cysteic acid is the chemical mediator of automotive clearcoat damage promoted by dragonfly eggs
Authors: Stevani Cassius V. , Liria Cleber W. , Miranda M. Terêsa M. , Bechara Etelvino J. H.
Published: August 2002

The damage caused by dragonfly eggs on automotive clearcoats exposed to sunlight occurs by a chemical mechanism similar to that caused by acid rain. Cysteine and cystine residues present in dragonfly eggs are oxidized during the egg hardening process, which releases hydrogen peroxide, to a cysteic acid derivative, a strong acid capable to catalyze the hydrolysis of acrylo/melamine clearcoat polymer. Cysteic acid was indeed identified and quantified by ion‐exchange HPLC in dragonfly egg extracts submitted to oxidation by H2O2 followed by acid digestion. Moreover, H2O2 concentration, temperature, and exposure time profiles of cysteic acid formation as well as an apparent activation energy for cysteine (in dragonfly eggs) oxidation to cysteic acid by H2O2 (32 ± 2 kJ/mol) were determined. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1549–1554, 2001
Unsaturated polyester resin modified with poly(organosiloxanes). II. Acoustic emission study on glass‐fiber‐reinforced resin
Authors: Rosa Valéria Maria , Karger‐Kocsis Jozsef , Felisberti Maria Isabel
Published: August 2002

This work aims to study the adhesion of an isophthalic acid based unsaturated polyester resin chemically modified by grafting copolymerization of a poly(organosiloxane) to the glass fiber. The failure mode of the single‐edge notched tensile specimen, cut from pressed plates containing 50 wt % of nontreated and silane‐treated milled glass fiber, was studied by acoustic emission (AE) technique. It was found that the aforementioned resin modification enhanced the adhesion between the fiber and the resin. This was suggested by a shift in the AE amplitude and energy toward higher values. On the other hand, the matrix modification had no significant effect if glass fiber with suitable unsaturated polyester resin (UP) sizing was incorporated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3280–3289, 2001
Formulation/property relationships in radiation‐cured poly(urethane methacrylate) pressure‐sensitive adhesives. II. Variation of the chain terminator component
Authors: Ansell C. W. G. , Masters S. J. , Millan E. J.
Published: August 2002

The synthesis of a series of radiation‐curable poly(urethane methacrylate) oligomers are reported, which, on exposure to electron‐beam irradiation, result in adhesive films with pressure‐sensitive properties. Variation of the chain terminator component of the formulation and the effect of this on adhesive properties were investigated. Adhesive systems utilizing Dowfax 9N6 nonylphenolethoxylate, 1‐(2‐hydroxyethyl)‐2‐pyrrolidinone, 2‐hydroxyethyl salicylate, or 4‐(2‐hydroxyethyl)morpholine as alternative chain terminators performed in a manner that may make them suitable for medical applications. Terminators with higher ethoxylation levels (Brij 35, 58) conferred high hydrophilicity on the resulting adhesives. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3321–3326, 2001
The potential of Cu(I)Cl/2,2′‐bipyridine catalysis in a triblock copolymer preparation by atom transfer radical polymerization
Authors: Masař Bohumil , Vlček Petr , Kříž Jaroslav
Published: August 2002

The ability of atom transfer radical polymerization (ATRP) in the sequential synthesis of triblock copolymers was examined using Cu(I)Cl/2,2′‐bipyridine catalysis at 110°C in toluene, starting from PMMA macroinitiators terminated with the C‐Br group. The PMMAs were prepared by living anionic or group transfer polymerization (GTP), followed by bromination of the respective active site with Br2 or N‐bromosuccinimide (NBS). The yield of the terminal bromination in the products of both living polymerizations was 60–64% at best, compared with the yield of the bromination of 1‐methoxy‐(1‐trimethylsilyloxy)prop‐1‐ene (a model of the GTP active site) with NBS, as found by 1H‐NMR. The PMMA macroinitiators prepared were utilized to start the sequential ATRP, finally affording PMMA‐b‐PBuA‐b‐PSt (Mn 69,100), PMMA‐b‐PSt‐b‐PBuA (Mn 21,300) and PMMA‐b‐PSt‐b‐PMMA (Mn 35,200), which have not yet been synthesized by ATRP. After the second block has been formed, the Br‐unterminated part of PMMA macroinitiator was removed by extraction or repeated precipitation. In the third (last) sequence polymerization, induction periods were observed. The first two triblock copolymers were free of precursors and have Mw/Mn values 1.5–1.6 (SEC). In the course of the last step of PMMA‐b‐PSt‐b‐PMMA synthesis, the content of the PMMA‐b‐PSt precursor slowly decreased with increasing MMA conversion. Still, at ≈90% MMA conversion, about 10–15% of the precursor remained in the product. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3514–3522, 2001
Preparation of polypropylene/acrylonitrile–styrene copolymer alloys by one‐step reactive blending
Authors: Xie Xu‐Ming , Liu Ya‐Yun , Guo Bao‐Hua , Feng Jun , Ishikawa Tatsuo , Morinaga Takashi
Published: August 2002

The compatibilization of polypropylene/acrylonitrile–styrene (PP/AS) blends through the addition of peroxide (DCP) was investigated in this study. The grafting reaction between PP and AS with the addition of peroxide occurred during the reactive‐blending process. The in situ‐formed grafting copolymers of PP‐g‐AS and AS‐g‐PP were then characterized by FTIR. The optimum concentration of the initiator, DCP, was 0.2 wt %, and the reaction temperature should be above 195°C. It was found that, when AS was the major component of the blends, the grafting of AS onto PP was the main process; conversely, when PP was the major component, PP was grafted onto AS. These results can be explained by the main‐chain scission of PP during the reactive‐blending process. With increase of the AS component, the total degree of grafting increased at first and then decreased after the composition of the blends reached 50/50. The maximum degree of grafting was found to be 6 wt % for the 50/50 PP/AS/DCP blend. PP was more degradable than was AS in the presence of peroxide at high temperatures. The MFR values of the PP/AS/DCP blends were slightly greater than were those of the simple PP/AS blends, which means that blending is an effective way to protect PP from degradation. SEM micrographs of the cross section of PP/AS/DCP showed a fine dispersion and a smaller domain size of the dispersed‐phase particles, implying that the in situ‐formed grafting copolymers act as a compatibilizer to reduce the interfacial tension between the PP and AS phases. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1284–1290, 2001
Drying of heterogeneous hydrogels formed with various water contents: A photon transmission study
Authors: Kara Selim , Pekcan Önder
Published: August 2002

Drying of acrylamide (AAm) gels was monitored by using a photon transmission technique. These hydrogels are formed from AAm and N,N′‐methylenebis(acrylamide) (Bis) with various water contents by the free‐radical crosslinking copolymerization (FCC). The transmitted light intensity, Itr, increased continuously as AAm gels were dried. The increase in Itr was attributed to the decrease in the scattered light intensity, Isc, which might be originated from the contrast between frozen blob clusters and holes in the drying gel. A decrease in Isc was modeled by using Rayleigh's equation where drying times with various exponents were found to be proportional to the size of the holes. It was observed that the radius of holes, ξc, decreased in various powers of the drying time depending on water content used during FCC. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1944–1951, 2001
Carbazole‐based electroluminescent devices obtained by vacuum evaporation
Authors: D'Almeida K. , Bernède J. C. , Ragot F. , Godoy A. , Diaz F. R. , Lefrant S.
Published: August 2002

Transparent conductive oxide (SnO2)/organic layers/aluminum thin film sandwich structures were obtained by vacuum evaporation. The organic component was either a thin carbazole film or a bilayer. In that case, the carbazole film was deposited onto a thin insulating polymer film. The polymer used was the poly(tetrabromo‐p‐phenyleneselenide) (PBrPDSe). Photoluminescence measurements have shown that the carbazole thin films emit blue light. (I‐V) measurements have shown that the structures exhibit diode characteristics. The forward direction is obtained when the transparent conductive oxide (TCO) is positively biased. However, the reproducibility of the results obtained with a single carbazole layer is poor. It appears that the stability of the sample is improved when a thin PBrPDSe film (40 nm) is introduced between the carbazole and the SnO2. The polymer film avoids the short circuit effect. In that case, the turn‐on voltage of the diode is about 3 V, when the thickness of the carbazole film is around 250 nm and the electroluminescence appears at a voltage of about 5 V. It is shown that the thermionic effect cannot be used to explain the I‐V characteristics, which are interpreted with the help of the Fowler–Nordheim tunnel effect. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2042–2055, 2001
Amphiphilic copolymers of glycidol with nonpolar epoxide comonomers
Authors: Royappa A. Timothy , Dalal Naresh , Giese Matthew W.
Published: August 2002

To explore the industrially used copolymerization of glycidol with other epoxide species, a series of copolymers of glycidol with various comonomers (epichlorohydrin, isopropyl glycidyl ether, 1,2‐epoxybutane, propylene oxide, and glycidyl phenyl ether) has been synthesized by cationic ring‐opening polymerization in dichloromethane, using boron trifluoride diethyl etherate as the initiator. The facile synthesis proceeded at room temperature under ordinary atmosphere. The air‐ and temperature‐stable products—mostly clear, colorless, viscous liquids—are proposed to consist of a hyperbranched polyglycidol core (incorporating varying fractions of comonomer) with arms made from comonomer‐derived repeat units. These copolymers had low molecular weights and rather broad molecular weight distributions. There was wide variation in the polarity of these copolymers, depending on the comonomer used, resulting in materials that were soluble in solvents ranging from benzene to water. The glass‐transition temperatures observed for these copolymers also varied widely, ranging from −56 to 1°C. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2290–2299, 2001
Cure kinetics of diglycidylether of bisphenol A– ethylenediamine revisited using a mechanistic model
Authors: Riccardi C. C. , Fraga F. , Dupuy J. , Williams R. J. J.
Published: August 2002

The polymerization kinetics of the reaction between diglycidylether of bisphenol A (DGEBA) and ethylenediamine (EDA) was analyzed, using dynamic scanning calorimetry, in both isothermal and programmed heating‐rate modes. A simple mechanistic model, consisting of an equilibrium reaction generating an epoxy–hydroxyl complex, and including two possible mechanisms for the consumption of amine hydrogens [(1) with free epoxy groups, (2) with the epoxy–hydroxyl complex], provided a reasonable fitting of the whole set of experimental results. It was found that the equilibrium constant decreased with temperature, making less important the reaction mechanism involving the epoxy–hydroxyl complex. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2319–2325, 2001
Kinetic evaluation of an oligomeric amidation reaction
Authors: Khan Abdul Rehman , Al‐Roomi Yousef M. , Mathew Johnson , Sari Majed
Published: August 2002

Homopoly(amides) similar to those of liquid crystalline poly(oxybenzoate) were prepared by acidolysis of the monomer p‐acetamidobenzoic acid. The kinetics of catalyzed and uncatalyzed acidolysis of the 4‐acetamidobenzoic acid were investigated at 265, 275, and 285°C. A second‐order rate model, which can analyze kinetic parameters of two different kinetic regimes, was used to interpret the experimental data for 18 different experimental sets. It is observed that the correlation coefficient between observed and calculated values range between 0.98 and 0.99, confirming the validity of the stated model. The nature of the kinetic behavior in the two regimes was found to be independent of both catalyst type and concentration. In effect second‐order rate law adequately describes the entire kinetic behavior of this system. The Arrhenius constants and activation energy parameters for this system have been reported. Differential scanning calorimetry (DSC) results of the oligomers indicate that the homopoly(amides) melt around 360°C with degradation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2534–2543, 2001
Application of differential scanning calorimetry and differential thermogravimetry techniques to determine the ratio of blend components in reactive chlorinated elastomer blends
Authors: Tripathy A. R. , Patra P. K. , Sinha J. K. , Banerji M. S.
Published: August 2002

Quantitative and qualitative analyses of chlorine‐containing elastomer blends, like neoprene rubber/chlorosulfonated polyethylene and neoprene rubber/nitrile–polyvinyl chloride, with carbon black and other fillers, are complex and confusing because the blends contain the same carbonchlorine moiety. Various interfering phenomena by fillers, co‐curing by the common ingredients, and uncertainty in functional group analysis make the determination of the ratio of component elastomers in chlorine‐containing elastomer blends very difficult or sometimes almost impossible by Fourier transform infrared and thermogravimetric analysis techniques. However, differential scanning calorimetry (DSC) and supportive differential thermogravimetry (DTG) are very useful techniques to assess such complex materials. Enough flexibility associated with specific heat (from DSC) and response zone (from DTG) can avoid the interfering effects. The DSC–DTG technique thus can be an effective tool to determine the ratio of component polymers in chlorine‐containing elastomer blends. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 937–948, 2002
Controlled radical polymerization catalyzed by CuCl/BDE complex in water medium. II. Polymerization of methyl methacrylate and formation of PMMA with bimodal molecular weight distribution
Authors: Wan Xiaolong , Liu Yanfei , Ying Shengkang
Published: August 2002

The emulsion polymerization of MMA was explored for the BDE/CuCl coordinated catalyst. The Mn of PMMA linearly increased both with increasing the monomer conversion and the proceeding polymerization time, which means that the MMA polymerized in “living”/controlled characters with zero order kinetics under BDE/CuCl‐catalyzed emulsion conditions. The apparent polymerization rate constants of MMA were k = 0.765 mol/min, k = 0.760 mol/min at 80°C, while k = 0.228 mol/min at 50°C, respectively. Slight differences of polymerization results were obtained when emulsifier lauryl phosphate (ADP) and Polyoxyethylene nonyl phenyl ether (OP‐10) were adapted in the polymerization. Based on the “coordinated radical cage” mechanism proposed particularly to the BDE/CuCl catalyzed polymerization, reversible equilibrium between common free radical and the coordinated “living” species should exist in this system. Increasing the amount of catalyst must affect the fast equilibrium between those two species, thus, also affecting the relative content in the emulsion circumstance. Therefore, PMMA, with bimodal molecular weight distribution, was achieved through this approach. The formation of PMMA with bimodal distribution was affected by concentration of catalyst and polymerization temperature. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 3076–3081, 2002; DOI 10.1002/app.2336
Active and passive remote sensors as a new technology for coastal and lagoon monitoring
Authors: Alberotanza Luigi
Published: August 2002

1. Important environmental problems of coastal and lagoon areas have stimulated interest in scientific research. Innovative technologies can provide good tools for observing phenomena and measuring parameters.

2. The short overviews given in this article refer to the results obtained using active remote sensors and passive remote sensors in practical applications to support monitoring and research activities.

3. Active sensors such as FLIDAR‐3 (Fluorescence Light Detection and Ranging) (optical), tomography (acoustical), and CODAR (Coastal Ocean Dynamics Applications Radar) (radio) emit their own electromagnetic energy to the investigated surface and sense the reflected energy from the surface; while the passive sensors, such as MIVIS (Multispectral Infrared and Visible Imaging Radiometer), NOAA (National Oceanographic and Atmospheric Agency)/AVHRR (Advanced Very High Resolution Radiometer) and Landsat/TM, do not emit energy but measure energy reflected/emitted to the sensor from the investigated surface. Copyright © 2001 John Wiley & Sons, Ltd.
Morphology‐based systematics (MBS) and problems with fossil hominoid and hominid systematics
Authors: Sarmiento Esteban E. , Stiner Eric , Mowbray Ken
Published: August 2002

The generalized/primitive nature of the hominoid dentition and often fragmentary nature of fossils, coupled with enthusiastic optimism for making revolutionary finds, has wreaked havoc with recognition of early human ancestors and reconstruction of fossil hominoid phylogeny. As such, the history of paleoanthropology is one of repeated misidentification of fossil ancestors and of occasional fraud. Although this history has led many workers to lose confidence in morphology based systematics (MBS), past and present misidentifications are actually due to a disregard of systematic methodology. Systematics depends on the continuity of life and gains its objectivity largely from the order alpha taxonomy imposes on morphologic discontinuities in closely related taxa (i.e., species and genera). Transformation of characters fixed in species into character complexes, as manifested in taxa nested at different levels of relationship, form the foundation for higher‐level taxonomy and for phylogeny. Because in most cases, hominoid fossils are unable to provide the data needed to resolve alpha taxonomy, classification and phylogeny of fossil taxa must be guided by analogies to living taxa. Hominid and hominoid fossil taxonomy and phylogeny, however, has been based largely on preevolutionary notions and on misinterpretations of the polarity of assumed diagnostic characters. More often than not, fossils lack resolution for the taxonomic level or rank they are assigned to and taxa are erected without appropriate analogies to living forms. As such, phylogenies based on these classifications are unlikely to be correct. More in‐depth anatomical studies that are in accordance with systematic methodology are likely to hold the key to correctly classifying fossils and unraveling hominoid and hominid phylogeny. Anat Rec (New Anat) 269:50–66, 2002. © 2002 Wiley‐Liss, Inc.
Intracranial distribution of the sympathetic system in mice: DiI tracing and immunocytochemical labeling
Authors: Maklad Adel , Quinn Thomas , Fritzsch Bernd
Published: August 2002

The intracranial distribution of the cephalic branches of the superior cervical ganglion (scg) was studied in mice using indocarbocyanine dye (DiI) anterograde tracing. Two main branches were traced from the scg. The first branch joined the nerve of the pterygoid canal (the vidian nerve), npc, from which several intracranial sympathetic branches passed to the branches of the trigeminal nerve (tgn), abducent nerve (abn), trochlear nerve (trn), and oculomotor nerve (ocn). Most of the second branch joined the abn, from which sympathetic fibers dispersed in the distal region of the trigeminal ganglion (tgg) to form a plexus close to the ganglion's branches. Branches from this plexus joined the branches of the tgn, trn, and ocn. Several minor branches arising from the second branch of the scg were also observed. One formed a sympathetic plexus around the internal carotid artery (ica); a second formed a sympathetic plexus in the proximal region of tgg, close to its root; and a third branch coursed laterally to reach the ear by passing along the greater petrosal nerve (gpn). All of the intracranial trajectories traced from scg were found to be catecholaminergic, and likely sympathetic, using tyrosine hydroxylase (TH) immunocytochemistry. Anat Rec 263:99–111, 2001. © 2001 Wiley‐Liss, Inc.
Anatomical distribution of NPY‐like immunoreactivity in the domestic chick brain (Gallus domesticus)
Authors: Esposito Vincenzo , Pelagalli Gaetano Vincenzo , De Girolamo Paolo , Gargiulo Giuliana
Published: August 2002

Neuropeptide Y‐immunoreactive (NPY‐ir) fibers and neurons in the brain of the domestic chick (Gallus domesticus) were described using an immunohistochemical technique. NPY‐ir neurons were seen in the lobus parolfactorius; hyperstriatum, neostriatum, paleostriatum, and archistriatum; hippocampal and parahippocampal areas; dorsolateral corticoid area; piriform cortex; two thalamic areas contiguous to the n. rotundus; n. dorsolateralis anterior thalami, pars lateralis, and pars magnocellularis; n. periventricularis hypothalami; n. paraventricularis magnocellularis; regio lateralis hypothalami; n. infundibuli; inner zone of the median eminence; dorsal and lateral portions of the n. opticus basalis; n. raphes; and n. reticularis paramedianus. NPY‐ir fibers were seen throughout the entire chick brain, but were more abundant in the hypothalamus where they formed networks and pathways. They were also observed in some circumventricular organs. The anatomical data of the present study regarding the distribution of NPY ir in the chick brain, together with the physiological findings of other studies, suggest that NPY plays a key role in the regulation of the neuroendocrine, vegetative, and sensory systems of birds by acting as a neuromodulator and/or neurotransmitter. Anat Rec 263:186–201, 2001. © 2001 Wiley‐Liss, Inc.
Modeling and remodeling in a developing artiodactyl calcaneus: A model for evaluating Frost's Mechanostat hypothesis and its corollaries
Authors: Skedros John G. , Mason Mark W. , Bloebaum Roy D.
Published: August 2002

The artiodactyl (mule deer) calcaneus was examined for structural and material features that represent regional differences in cortical bone modeling and remodeling activities. Cortical thickness, resorption and formation surfaces, mineral content (percent ash), and microstructure were quantified between and within skeletally immature and mature bones. These features were examined to see if they are consistent with predictions of Frost's Mechanostat paradigm of mechanically induced bone adaptation in a maturing “tension/compression” bone (Frost,1990a,b, Anat Rec 226:403–413, 414–422). Consistent with Frost's hypothesis that surface modeling activities differ between the “compression” (cranial) and “tension” (caudal) cortices, the elliptical cross‐section of the calcaneal diaphysis becomes more elongated in the direction of bending as a result of preferential (> 95%) increase in thickness of the compression cortex. Regional differences in mineral content and population densities of new remodeling events (NREs = resorption spaces plus newly forming secondary osteons) support Frost's hypothesis that intracortical remodeling activities differ between the opposing cortices: 1.) in immature and mature bones, the compression cortex had attained a level of mineralization averaging 8.9 and 6.8% greater (P< 0.001), respectively, than that of the tension cortex, and 2.) there are on average 350 to 400% greater population densities of NREs in the tension cortices of both age groups (P< 0.0003). No significant differences in cortical thickness, mineral content, porosity, or NREs were found between medial and lateral cortices of the skeletally mature bones, suggesting that no modeling or remodeling differences exist along a theoretical neutral axis. However, in mature bones these cortices differed considerably in secondary osteon cross‐sectional area and population density. Consistent with Frost's hypothesis, remodeling in the compression cortex produced bone with microstructural organization that differs from the tension cortex. However, the increased remodeling activity of the tension cortex does not appear to be related to a postulated low‐strain environment. Although most findings are consistent withpredictionsof Frost's Mechanostat paradigm, there are several notable inconsistencies. Additional studies are needed to elucidate the nature of themechanismsthat govern the modeling and remodeling activities that produce and maintain normal bone. It is proposed that the artiodactyl calcaneus will provide a useful experimental model for these studies. Anat Rec 263:167–185, 2001. © 2001 Wiley‐Liss, Inc.