bluuebunny/crossref_metadata_2025 huggingface dataset:
The influence on human osteoblasts in vitro of non-steroidal anti-inflammatory drugs which act on different cyclooxygenase enzymes
Authors: Evans C. E. , Butcher C.
Published: April 2004

There is increasing evidence that non-steroidal anti-inflammatory drugs (NSAIDs) can adversely affect bone repair. We have, therefore, studied the in vitro effects of NSAIDs, which differentially inhibit cyclooxygenases (COX), the prostaglandin/thromboxane synthesising enzymes, on human osteoblasts. Indomethacin and the new nitric oxide (NO)-donating NSAIDs block the activity of both COX-1 and COX-2. Indomethacin and 5,5-dimethyl-3-(3 fluorophenyl)-4-(4 methylsulphonal) phenyl-2 (5H)-furanone (DFU) reduced osteoblast numbers in a dose-dependant manner and increased collagen synthesis and alkaline phosphatase activity. The reduction in osteoblast numbers was not caused by loss of adhesion and was reversible. Neither NSAID influenced DNA synthesis. There was no difference between the effects of indomethacin and DFU. NO-NSAIDs did not affect cell numbers.

These results suggest that care should be taken when administering NSAIDs to patients with existing skeletal problems and that NO-NSAIDs may be safer.
Pattern of diabetic neuropathic arthropathy associated with the peripheral bone mineral density
Authors: Herbst S. A. , Jones K. B. , Saltzman C. L.
Published: April 2004

The relationship between the bone mineral density (BMD) and Charcot arthropathy is unclear. Prospectively, 55 consecutive diabetic patients presenting with a Charcot arthropathy of the foot or ankle were classified as having a fracture, dislocation, or a combination fracture-dislocation pattern of initial destruction. In these groups we used dual-energy x-ray absorptiometry to compare the peripheral bone of the affected and unaffected limbs. The clinical data relating to diabetes and related major comorbidities and the site of the arthropathy (ankle, hindfoot, midfoot, forefoot) were also compared. There were 23 patients with a fracture pattern, 23 with a dislocation pattern, and nine with a combination.

The age-adjusted odds ratio for developing a Charcot joint with a fracture pattern as opposed to a dislocation pattern in patients with osteopenia was 9.5 (95% confidence interval 2.4 to 37.4; p = 0.0014). Groups also differed as to the site of the arthropathy. Fracture patterns predominated at the ankle and forefoot whereas dislocations did so in the midfoot. Diabetic Charcot arthropathy of the foot and ankle differs according to the pattern of the initial destruction. The fracture pattern is associated with peripheral deficiency of BMD. The dislocation pattern is associated with a normal BMD.
Third sector participation in the policy process: a framework for comparative analysis
Authors: Casey John
Published: April 2004

English

Do third sector organisations (TSOs) participate meaningfully in the public policy process? What factors determine their access to decision-making domains or their ability otherwise to influence political outcomes? This article presents a framework for the analysis of the participation of TSOs in the policy process based on four factors: the political opportunities offered by the polity in which they operate; the nature of the policies they are seeking to influence; the characteristics and the resources of the organisations themselves; and the network of other political actors. The framework utilises a multi-disciplinary approach, combining elements from political science, sociology and organisational theory.
Antigenicity Analysis of Different Regions of the Severe Acute Respiratory Syndrome Coronavirus Nucleocapsid Protein
Authors: Chen Zeliang , Pei Decui , Jiang Lingxiao , Song Yajun , Wang Jin , Wang Hongxia , Zhou Dongsheng , Zhai Junhui , Du Zongmin , Li Bei , Qiu Maofeng , Han Yanping , Guo Zhaobiao , Yang Ruifu
Published: April 2004

Background: The widespread threat of severe acute respiratory syndrome (SARS) to human health has made urgent the development of fast and accurate analytical methods for its early diagnosis and a safe and efficient antiviral vaccine for preventive use. For this purpose, we investigated the antigenicity of different regions of the SARS coronavirus (SARS-CoV) nucleocapsid (N) protein.

Methods: The cDNA for full-length N protein and its various regions from the SARS-CoV was cloned and expressed in Escherichia coli. After purification, all of the protein fragments were printed on glass slides to fabricate a protein microarray and then probed with the sera from SARS patients to determine the reactivity of these protein fragments.

Results: The full-length protein and two other fragments reacted with all 52 sera tested. Four important regions with possible epitopes were identified and named as EP1 (amino acids 51–71), EP2 (134–208), EP3 (249–273), and EP4 (349–422), respectively. EP2 and EP4 possessed linear epitopes, whereas EP1 and EP2 were able to form conformational epitopes that could react with most (>80%) of the tested sera. EP3 and EP4 also formed conformational epitopes, and antibodies against these epitopes existed in all 52 of the sera tested.

Conclusion: The N protein is a highly immunogenic protein of the SARS-CoV. Conformational epitopes are important for this protein, and antigenicity of the COOH terminus is higher than that of the NH2 terminus. The N protein is a potential diagnostic antigen and vaccine candidate for SARS-CoV.
Aggregation of 1-Palmitoyl-2-Oleoyl-Sn-Glycero-3-Phosphocholine in Nonaqueous Solutions Studied by Spectroscopic and Kinetic Probe Molecules and Dynamic Light Scattering
Authors: Wen Shaoying , Kohlstrunk Bernd , Helmstedt Martin , Knoll Helmut
Published: April 2004

The aggregation behavior of 1-Palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) in the nonaqueous solvents formamide (FA) and 3-hydroxypropionitrile (HPN) has been studied. UV/Vis absorption maximum λmax and thermal cis → trans isomerization rate constant k
iso of an azo dye, as well as fluorescence intensity ratios I
M/I
E of monomer and excimer, and the excimer lifetime τE of two dipyrenyl compounds as probe molecules have been determined. For comparison, aggregation of the amphiphile POPC molecules was followed “probe-free” by means of dynamic light scattering (DLS) measurements. Combining the results of probe molecule studies and DLS it turned out that the critical aggregation concentration of POPC in FA < 0.05mmol dm−3. At ≥ 0.2mmol dm−3, aggregates have hydrodynamic radii 30 < R
h < 80nm and high microviscosity in their hydrocarbon interior. A vesicle-like structure of the aggregates can therefore be assumed. Aggregation behavior of POPC in HPN is much less pronounced, essentially small aggregates with radii of a few nanometer have been detected which include solvent molecules.
The Four Isotopomer Reactions of NH(a) and ND(a) with NH3(X̃) and ND3(X̃)
Authors: Adam L. , Hack W. , Olzmann Matthias
Published: April 2004

The reactions

NH(a) + NH3(X̃) → products (1)

ND(a) + NH3(X̃) → products (2)

NH(a) + ND3(X̃) → products (3)

ND(a) + ND3(X̃) → products (4)

were studied in a quasi-static reaction cell at room temperature and pressures of 10 and 20mbar with He as the main carrier gas. The electronically excited reactants NH(a) and ND(a) were generated by laser-flash photolysis of HN3 and DN3, respectively, at λ = 308nm and detected by laser-induced fluorescence (LIF). Also the ground state species NH(X) and ND(X) as products were detected by LIF.

From the measured concentration-time profiles of NH(a) and ND(a) under pseudo-first order conditions, the following rate constants were obtained:

NH(a) + NH3(X̃) → products (1)

ND(a) + NH3(X̃) → products (2)

NH(a) + ND3(X̃) → products (3)

ND(a) + ND3(X̃) → products (4)

k
1 = (9.1 ± 0.9) × 1013 cm3mol−1s−1

k
2 = (9.6 ± 1.0) × 1013 cm3mol−1s−1

k
3 = (8.0 ± 1.0) × 1013 cm3mol−1s−1

k
4 = (7.2 ± 0.8) × 1013 cm3mol−1s−1.

The major products are the corresponding NH
i
D2 −

i
(X̃) radicals (i = 0, 1, 2), whereas quenching processes such as NH(a) + ND3 → NH(X) + ND3 are of minor importance (1%). The isotope exchange NH(a) + ND3 → ND(X) + NHD2 is negligible, and the corresponding channel on the singlet surface NH(a) + ND3(X
~) → ND(a) + NHD2(X̃) contributes with 1% to the overall NH(a) depletion in that reaction. The experimental findings are discussed in terms of a chemical activation mechanism by means of statistical rate theory.
A genome wide search for alcoholism susceptibility genes
Authors: Hill Shirley Y. , Shen Sa , Zezza Nicholas , Hoffman Eric K. , Perlin Mark , Allan William
Published: April 2004

Alcoholism is currently one of the most serious public health problems in the US. Lifetime prevalence rates are relatively high with one in five men and one in 12 women meeting criteria for this condition. Identification of genetic loci conferring an increased susceptibility to developing alcohol dependence could strengthen prevention efforts by informing individuals of their risk before abusive drinking ensues. Families identified through a double proband methodology have provided an exceptional opportunity for gene‐finding because of the increased recurrence risks seen in these sibships. A total of 360 markers for 22 autosomes were spaced at an average distance of 9.4 cM and genotyping performed for 330 members of these multiplex families. Extensive clinical data, personality variation, and event‐related potential characteristics were available for reducing heterogeneity and detecting robust linkage signals. Multipoint linkage analysis using different analytic strategies give strong support for loci on chromosomes 1, 2, 6, 7, 10, 12, 14, 16, and 17. © 2004 Wiley‐Liss, Inc.
Recognition of facial features of fetal alcohol syndrome in the newborn
Authors: Stoler Joan Marilyn , Holmes Lewis Ball
Published: April 2004

The diagnosis of an infant, especially a newborn, with fetal alcohol spectrum disorder is difficult due to the fact that not all of the features are apparent at that time. Many cases are also missed due to inadequate knowledge of the mother's drinking pattern and because of the examining physician's lack of experience with the disorder. While conducting a study of the use of maternal blood markers to determine alcohol use in pregnancy, we have evaluated systematically the effects of alcohol on the newborn infant. We have developed a facial scoring system consisting of six of the features commonly seen in children with fetal alcohol syndrome (FAS) and present preliminary data about its use. By using a cutoff of four or more of these six features, there is a significant correlation with the presence of these features and the mother's self‐reported alcohol use. In addition, there has been no significant difference in the frequency of positive scores between newborns of Caucasian or Black ancestry. We propose that this system may be useful in the assessment of newborn infants at high risk because of alcohol exposure during pregnancy. © 2004 Wiley‐Liss, Inc.
An analysis of the effects of prenatal alcohol exposure on growth: A teratologic model
Authors: Day Nancy L. , Richardson Gale A.
Published: April 2004

The association between prenatal exposure to alcohol and growth is linear, and effects have been measured at levels of exposure that are considerably below one drink per day. Thus, with respect to growth deficits, there is no safe level of drinking during pregnancy. Alcohol exposure during gestation causes growth deficits among the offspring at birth and during infancy. At older ages, however, growth deficits are reported in some, though not all, studies. Exposed offspring who grow up in more privileged environments are apparently able to make up their growth deficits, while those raised in less optimal circumstances do not. This means that there is an interaction between the environment in which a child is raised and the expression of the effects of prenatal alcohol exposure. The long‐term implications of growth deficits are not yet well understood. © 2004 Wiley‐Liss, Inc.
Teratogenic effects of alcohol: A decade of brain imaging
Authors: Riley Edward P. , McGee Christie L. , Sowell Elizabeth R.
Published: April 2004

Heavy alcohol exposure can have serious and long‐lasting effects on the developing fetal brain. In the last decade, researchers have utilized quantitative structural magnetic resonance imaging (MRI) to examine the brains of living children and adults with histories of heavy prenatal alcohol exposure. In addition to microcephaly, these studies indicated structural abnormalities in various regions of the brain, including the cerebellum, corpus callosum, and the basal ganglia. Most recently, we have utilized novel imaging and analytic techniques to study the brain as a whole in an effort to elucidate more subtle differences than was possible with earlier techniques. Results indicated displacements in the corpus callosum, increased gray matter densities in both hemispheres in the perisylvian regions, and altered gray matter asymmetry in portions of the temporal lobes in the brains of alcohol‐exposed subjects. In addition, prominent shape abnormalities were observed in the brains of these subjects, with narrowing in the temporal region and reduced brain growth in portions of the frontal lobe. These results imply that brain growth continues to be adversely affected long after the prenatal insult and that the brain regions most affected may be consistent with the neurocognitive deficits characteristic of individuals prenatally exposed to alcohol. © 2004 Wiley‐Liss, Inc.
Nichtkoordinierende Anionen – Traum oder Wirklichkeit? Eine Übersicht zu möglichen Kandidaten
Authors: Krossing Ingo , Raabe Ines
Published: April 2004

Gibt es so etwas wie ein wirklich nichtkoordinierendes Anion? Wäre es nicht großartig, jede verrückte, schöne oder einfach nur nützliche kationische Spezies herstellen zu können, sei es, weil sie einen gerade interessiert oder weil man sie vielleicht schon einmal im Massenspektrum entdeckt hat? Um dieses Ziel in kondensierter Phase zu erreichen, müssen die Zielkationen mit einem geeigneten Gegenion versehen werden – dies ist der Moment, bei dem häufig Schwierigkeiten auftreten und viele gute Ideen wegen einer Koordination oder Zersetzung des Anions im Abguss enden. Zur Lösung des Problems bietet sich womöglich eines der neuen schwach koordinierenden Anionen (WCAs) an, die Gegenstand dieses Aufsatzes sind. Vorgestellt werden neue Entwicklungen, Anwendungen, Ausgangsmaterialien und allgemeine Strategien zur Einführung von WCAs in ein System. Einige der ungewöhnlichen Eigenschaften von WCA‐Salzen wie hohe Löslichkeit in unpolaren Medien, Pseudo‐Gasphasenbedingungen in der kondensierten Phase oder die Stabilisierung von schwach gebundenen und niedrig geladenen Komplexen werden anhand thermodynamischer Betrachtungen plausibel gemacht. Die Grenzen bei der Verwendung von WCAs – durch Koordination und Zersetzung – werden aufgezeigt, und eine quantenchemische Analyse der WCA‐Typen wird vorgestellt. Dies ermöglicht es, die Entscheidung für ein spezielles WCA auf der Basis von harten quantitativen Daten aus einer Vielzahl von Anionen zu gründen.
Titelbild: Giant Single‐Molecule Magnets: A {Mn84} Torus and Its Supramolecular Nanotubes (Angew. Chem. 16/2004)
Authors: Tasiopoulos Anastasios J. , Vinslava Alina , Wernsdorfer Wolfgang , Abboud Khalil A. , Christou George
Published: April 2004

Das Riesenmolekül {Mn84} verbindet den molekularen Bottom‐up‐Ansatz mit dem klassischen Top‐down‐Verfahren zur Herstellung nanoskaliger magnetischer Materialien. Im Titelbild symbolisiert der {Mn84}‐Ring (Durchmesser ca. 4.3 nm) den Brückenschlag zwischen den Welten des Quantenmagnetismus (molekulare Cluster {Mn4} und {Mn12}) und des klassischen Magnetismus (Cobalt‐Nanopartikel) vor der Kulisse der 1659 erbauten Manolis‐Brücke über den Agrafiotis in der griechischen Region Euritanien. Näheres erfahren Sie in der Zuschrift von G. Christou et al. auf S. 2169 ff.
Noncoordinating Anions—Fact or Fiction? A Survey of Likely Candidates
Authors: Krossing Ingo , Raabe Ines
Published: April 2004

Is there anything resembling a truly noncoordinating anion? Would it not be great to be able to prepare any crazy, beautiful, or simply useful cationic species that one has in mind, or has detected by mass spectroscopy? In condensed phases the target cation has to be partnered with a suitable counteranion. This is the moment when difficulties arise and many wonderful ideas end in the sink owing to coordination or decomposition of the anion. However, maybe these counteranion problems can be overcome by one of the new weakly coordinating anions (WCAs). Herein is an overview on the available candidates in the quest for the least coordinating anion and a summary of new applications, available starting materials, and general strategies to introduce a WCA into a system. Some of the unusual properties of WCA salts such as high solubility in low dielectric media, pseudo gas‐phase conditions in condensed phases, and the stabilization of weakly bound and low‐charged complexes are rationalized on thermodynamic grounds. Limits of the WCAs, that is, anion coordination and decomposition, are shown and a quantum chemical analysis of all types of WCAs is presented which allows the choice of a particular WCA to be based on quantative data from a wide range of different anions.
Cover Picture: Giant Single‐Molecule Magnets: A {Mn84} Torus and Its Supramolecular Nanotubes (Angew. Chem. Int. Ed. 16/2004)
Authors: Tasiopoulos Anastasios J. , Vinslava Alina , Wernsdorfer Wolfgang , Abboud Khalil A. , Christou George
Published: April 2004

The giant single‐molecule {Mn84} (diameter ca. 4.3 nm), bridges the molecular (bottom‐up) and classical (top‐down) approaches to nanoscale magnetic materials. The cover shows the {Mn84} toroidal molecule as a bridge between the quantum ({Mn4} and {Mn12} clusters) and classical (a Co nanoparticle) worlds of magnetism. The photo is of the Manolis' bridge built in 1659 across the Agrafiotis river in Greece. For further details see the Communication by G. Christou and co‐workers on page 2117 ff.
Combined experimental and computer simulation study of the kinetics of solute release from a relaxing swellable polymer matrix. II. Release of an osmotically active solute
Authors: Papadokostaki K. G.
Published: April 2004

The performance of a model monolithic controlled release device, consisting of a swellable polymeric matrix subject to structural relaxation (cellulose acetate), loaded with a simple osmotically active solute (NaCl) and activated by the ingress of solvent (water), was studied experimentally and by computer simulation. The former study involved detailed monitoring of the kinetics of both solute release and solvent absorption (followed in due course by desorption of osmotically imbibed excess solvent). The computer simulation study was based on extensive previous modeling work. Values of the relevant input model parameters were derived from independent experimental measurements of the sorption and diffusion properties of solvent (cf. Part I) and solute (reported in the present article). The resulting simulation was highly successful, considering that it proved possible to simulate closely and consistently the kinetics of both solute release (over practically the whole experimental range) and concurrent solvent absorption (including correct prediction of the magnitude of the osmotically induced excess swelling of the polymeric matrix). Simulation of the final desorption of osmotically imbibed water was facilitated by the realization that this process actually reflects the kinetics of a long‐term deswelling relaxation of the polymer structure back to the state of normal hydration, the rate of which could be measured to a good approximation on the pure deswelling polymer. The results presented here are of obvious practical significance in relation to progress toward computer‐assisted design of monolithic controlled release devices exhibiting relatively complex kinetic behavior. They should also prove useful by calling attention to an important caveat when desorption into water is used as a method for the straightforward determination of solute diffusivity in hydrated polymers, in cases of osmotically active solutes diffusing in nonhydrophilic polymers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2468–2479, 2004
Material characterization of a high‐dielectric‐constant polymer–ceramic composite for embedded capacitor for RF applications
Authors: Rao Yang , Wong C. P.
Published: April 2004

Embedded capacitor technology can improve electrical performance and reduce assembly cost compared with traditional discrete capacitor technology. Polymer–ceramic composites have been of great interest as embedded capacitor materials because they combine the processability of polymers with the desired electrical properties of ceramics. We have developed a novel nanostructure polymer–ceramic composite with a very high dielectric constant (εr ≈ 150, a new record for the highest reported εr value of a nanocomposite) in a previous work. RF applications of embedded capacitors require that the insulating material have a high εr at a high frequency (in the gigahertz range), low leakage current, high breakdown voltage, and high reliability. A set of electrical tests were conducted in this study to characterize the electrical properties of the novel high‐εr polymer–ceramic nanocomposite developed in‐ house. The results show that this material had a fairly high εr in the RF range, low electrical leakage, and high breakdown voltage. An 85°C/85% thermal humidity aging test was been performed, and it showed that this novel high‐K material had good reliability. An embedded capacitor prototype with a capacitance density of 35 nF/cm2 was manufactured with this nanocomposite with spin‐coating technology. This novel nanocomposite can be used for the integral capacitors for RF applications. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2228–2231, 2004
Synthetic, structural, and thermal degradation of a tercopolymer derived from salicylic acid, guanidine, and formaldehyde
Authors: Michael Pratik E. P. , Lingala Peter S. , Juneja H. D. , Paliwal L. J.
Published: April 2004

A salicylic acid–guanadine–formaldehyde (SGF) tercopolymer was synthesized by the condensation of salicylic acid with guanidine carbonate and formaldehyde in 1 : 1 : 2 molar proportions in the presence of 2M HCl as a catalyst. The SGF tercopolymer was characterized on the basis of elemental analysis and ultraviolet–visible, IR, and NMR spectral studies. The Freeman–Carroll and Sharp–Wentworth methods were used to calculate the activation energy and thermal stability of the tercopolymer. Kinetic parameters such as activation energy, entropy change, free‐energy change, frequency factor, apparent entropy change, and order of reaction were calculated with the Freeman–Carroll method. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2278–2283, 2004
Reactive processing of nonmiscible polymers: Shear rate effect
Authors: David J. C. , Chalamet Y. , Taha M.
Published: April 2004

The effect of shearing in a corotating twin‐screw extruder on the apparent kinetic rate of model reactions was studied. Oxazoline‐terminated oligomers with different molar masses were prepared and used in condensation reactions with carboxylic acid terminated oligomers. A miscibility study of these oligomers allowed the choice of miscible and nonmiscible reactive systems. Reactions were first conducted in a glass reactor and then in the kneading‐disc area of a corotating twin‐screw extruder modified to neutralize the transport along the screws. For nonmiscible reactive systems, reactions were slower than equivalent reactions with miscible reactants. A shear increase for these nonmiscible reactants resulted in an increase in the apparent kinetic rate, which was in all cases lower than the rate obtained for miscible reactants. For very high shear rates, mechanical degradation was observed. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2357–2362, 2004
Depolymerization of poly(trimethylene terephthalate) in supercritical methanol
Authors: Zhang Hao‐Hong , Xiang Hong‐Wei , Yang Yong , Xu Yuan‐Yuan , Li Yong‐Wang
Published: April 2004

The depolymerization of poly(trimethylene terephthalate) (PTT) in supercritical methanol was carried out with a batch‐type autoclave reactor at temperatures ranging from 280 to 340°C, at pressures ranging from 2.0 to 14.0 MPa, and for reaction time of up to 60 min. PTT quantitatively decomposed into dimethyl terephthalate (DMT) and 1,3‐propaniol (PDO) under the designed conditions. The yields of DMT and PDO greatly increased as the temperature rose. The yields of the monomers markedly increased as the pressure increased to 10.0 MPa, and they leveled off at higher pressures. The final yield of DMT at 320°C and 10.0 MPa reached 98.2%, which was much closer to the extent of the complete reaction. A kinetic model was used to describe the depolymerization reaction, and it fit the experimental data well. The dependence of the forward rate constant on the reaction temperature was correlated with an Arrhenius plot, which gave an activation energy of 56.8 kJ/mol. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2363–2368, 2004
Pervaporation of 1,2‐dimethoxyethane from aqueous solutions by crosslinked oligosilylstyrene–poly(dimethylsiloxane) composite membranes
Authors: Liang Liang , Dickson James M. , Jiang Jianxiong , Brook Michael A.
Published: April 2004

Crosslinked oligosilylstyrene–poly(dimethylsiloxane) composite membranes were used to separate 1,2‐dimethoxyethane (1,2‐DME) from dilute aqueous solutions through a pervaporation process. The composite membranes were prepared through the casting of solutions of H‐terminated oligosilylstyrene and vinyl‐terminated poly(dimethylsiloxane) onto the surfaces of polysulfone ultrafiltration membranes. A crosslinked poly(dimethylsiloxane) gel was generated through the reaction of H‐terminated oligosilylstyrene and vinyl‐terminated poly(dimethylsiloxane), with a platinum complex used as a catalyst. The pervaporation characteristics of the composite membranes were investigated with respect to the feed composition of 1,2‐DME, the feed temperature, the downstream pressure, and the top‐layer thickness of the composite membranes. The composite membranes exhibited preferential selectivity to 1,2‐DME. Depending on the operation conditions, the separation factor and permeation rate of 1,2‐DME were 55–184 and 0.31–3.3 g/m2 h, respectively. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2284–2294, 2004
Ketone derivatives of diels‐alder adducts of levopimaric acid with acrylic acid and maleic anhydride: Synthesis, characterization, and polymerization
Authors: Bicu Ioan , Mustata Fanica
Published: April 2004

Two new ketone‐type derivatives were synthesized by the dehydrodecarboxylation of levopimaric acid acrylic acid adduct and of levopimaric acid maleic anhydride adduct in the presence of sulfonic catalysts. The two compounds were also synthesized by coupling of acrylic acid or maleic anhydride with dipimaryl ketone. These ketones, or rather ketone‐diacids, were condensed with polyalkylenepolyamines to give poly(amide)s or poly(imide)s with good thermal properties. New crosslinked polymers were obtained when these poly(amide)s or poly(imide)s were substituted with epichlorohydrin. The structures of the resulted ketone‐diacids and polymers were investigated by the usual physical and chemical methods. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2240–2252, 2004
Absorption of trioctyl trimellitate into mass‐polymerization and suspension‐polymerization poly(vinyl chloride)
Authors: Luo Yuxiang , Dai Gance
Published: April 2004

Poly(vinyl chloride) (PVC) slush powder has been widely used; we prepared it by dry blending. We found that the absorption of plasticizer by the PVC resins was the most important factor in the dry‐blending process and, further, that different types of PVC resin had different absorption rates. This results of this study provide new information about the relationship of absorption to PVC and other parameters. Haake rheomix testing and the quantity of plasticizers absorbed by the PVC resins were used to characterize the absorption process. Suspension‐polymerization poly(vinyl chloride) (SPVC) and mass‐polymerization poly(vinyl chloride) (MPVC) in different sizes were used for the test. The results showed that the MPVC absorbed the plasticizer more quickly than SPVC, especially at a higher temperature. However, for the same PVC resin type, the absorbing speeds were nearly independent of particle size. The studies that used a scanning electric microscope and specific surface area revealed that the morphology of the two types of particles was different. The surfaces of the individual particles of SPVC were smoother than those of MPVC. There was a “skin” covering the SPVC particles, whereas with the MPVC particles, the primary polymer was exposed directly on the surface. This difference in morphology was shown to be a significant factor in the different rates of absorption of the plasticizers for the different PVC resins. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2369–2374, 2004
Advances in stereolithography: A new experimental technique in the production of a three‐dimensional plastic model with an infrared laser
Authors: Jardini A. L. M. , Maciel R. F. , Scarparo M. A. F. , Andrade S. R. , Moura L. F. M.
Published: April 2004

The development of a new approach for the production of three‐dimensional plastic parts, called infrared laser stereolithography, is presented. During the experimentation, a carbon dioxide (CO2) laser beam at 10.6 μm (infrared radiation) was focused on a sample composed of an epoxy resin, diethylene triamine (curing agent), and silica powder (filler). The CO2 laser, adopted for cost reduction, led to no significant shrinkage, and almost no postcure treatment was required. With differential scanning calorimetry, it was possible to determine the reaction rate as a function of the temperature and the activation energy of the curing process. The solution of the heat equation, with the Ansys program simulating this process, was in general agreement with our previous observations of the stereolithography results. The experimental results of the production of solid parts layer by layer in three dimensions are presented. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2387–2394, 2004
Synthesis and characterization of new soluble poly(ester‐imide)s containing noncoplanar 2,2′‐dimethyl‐4,4′‐biphenylene unit
Authors: Liaw Der‐Jang , Fan Chi‐Lung , Lin Chi‐Cheng , Wang Kun‐Li
Published: April 2004

A new diimide–diacid chloride (3) containing a noncoplanar 2,2′‐dimethyl‐4,4′‐biphenylene unit was synthesized by treating 2,2′‐dimethyl‐4,4′‐diamino‐biphenylene with trimellitic anhydride followed by refluxing with thionyl chloride. Various new poly(ester‐imide)s were prepared from 3 with different bisphenols by solution polycondensation in nitrobenzene using pyridine as hydrogen chloride quencher at 170°C. Inherent viscosities of the poly(ester‐imide)s were found to range between 0.31 and 0.35 dL g−1. All of the poly(ester‐imide)s, except the one containing pendent adamantyl group 5e, exhibited excellent solubility in the following solvents: N,N‐dimethylformamide, tetrahydrofuran, tetrachloroethane, dimethyl sulfoxide, N,N‐dimethylacetamide, N‐methyl‐2‐pyrrolidinone, m‐cresol, o‐chlorophenol, and chloroform. The polymers showed glass‐transition temperatures between 166 and 226°C. The 10% weight loss temperatures of the poly(ester‐imide)s, measured by TGA, were found to be in the range between 415 and 456°C in nitrogen. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2486–2493, 2004
Melt grafting of 10‐undecenoic acid onto linear low density polyethylene
Authors: Ciolino A. , Vallés E. M. , Failla M. D.
Published: April 2004

The melt grafting of 10‐undecenoic acid (UA) onto a linear low‐density polyethylene (LLDPE) was studied. The grafting reaction was performed in a thermoplastic mixer and 2,5‐dimethyl‐2,5‐di(tert‐butylperoxy) hexane was used as initiator. The concentration of UA and peroxide ranged from 1 to 4% (w/w) and 0.025 to 0.1% (w/w), respectively. Evidence of the grafting of UA as well as its extent was determined by FTIR. Experimental results showed that the amount of UA grafted increases with both the UA and initiator concentrations. However, the greatest efficiency of grafting was found at the lowest concentration of UA investigated. The grafting efficiency ranged from 8 to 40%. The dynamic linear viscoelastic properties of the original polymer and the grafted materials were evaluated at different frequencies at 160°C using a dynamic rotational rheometer. The modification process affected the melt elasticity and viscosity of the LLDPE. When the original polymer was modified only with peroxide both properties increased with respect to those of the original material. However, when UA was grafted onto LLDPE, the resulting polymers displayed values of elastic moduli and viscosity lower than those of the polymer modified with peroxide. Moreover, when a concentration of 4% of UA was used, the values of those properties were even lower than those corresponding to the original LLDPE. These observations combined with the data obtained from the GPC results suggest that scission reactions may be favored by the presence on UA. In contrast with previous observations, the thermal properties measured by DSC were only slightly altered. The fusion temperature of the modified polymers was slightly lower than that corresponding to the original polymer. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2303–2311, 2004
Mechanism study on surface activation of surfactant‐modified polyvinyl siloxane impression materials
Authors: Lee Doug‐Youn , Oh Young‐Il , Chung Kyung‐Ho , Kim Kwang‐Mahn , Kim Kyoung‐Nam
Published: April 2004

This study examined the mechanism on the surface activation of hydrophilic polyvinyl siloxane impression materials incorporated with nonionic surfactants. Hydrophilic polyvinyl siloxane impression materials were prepared with a polydimethylsiloxane composition and nonionic surfactants. The surfactants used were nonylphenoxy poly(ethyleneoxy) ethanol homologs of varying ethyleneoxy chain length. These homologs were designated NP4, NP6, and NP10 according to the mole number of ethyleneoxy group (hydrophilic group) of 4, 6, and 10, respectively. The incorporation of a nonionic surfactant into polyvinyl siloxanes enhanced their hydrophilicity and consequently led to the significant reduction in the contact angles. The higher the concentration of surfactant that was incorporated, the lower the contact angles that were observed. The contact angle was lowest when NP4 was incorporated, even though NP4 is less hydrophilic than NP6 and NP10, which implies that the exposed surfactant concentration on the surface was highest when NP4 was used. Relatively lower surface energy of NP4 among three surfactants would induce spatial distribution of NP4 on the hydrophobic surface of polyvinyl siloxane and consequently resulted in higher surfactant concentration on the surface of the silicone impression material. The surfactant dispersion size also seemed to be relevant for the surface activation in these surfactant‐modified silicone impression materials. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2395–2401, 2004
Reduction of offensive odor from natural rubber by odor‐reducing substances
Authors: Hoven Vipavee P. , Rattanakarun Kesinee , Tanaka Yasuyuki
Published: April 2004

A number of chemicals including carbon black, chitosan, benzalkonium chloride, sodium dodecyl sulfate, cyclodextrin, and zeolite13x were tested as odor‐reducing fillers. The rationale is based on the concept of using odor absorbents/adsorbents for which both physical adsorption and chemical adsorption play an important role in odor reduction. The fillers were incorporated into highly odorous natural rubber (STR20 and RSS5) by physical mixing prior to sulfur vulcanization. As identified by gas chromatography and gas chromatography/mass spectrometry, the unpleasant odor mainly originates from low molecular weight volatile fatty acids. The quantity of acetic acid, a representative of odor molecule, can be significantly reduced in the presence of chitosan and zeolite13x. Although carbon black and cyclodextrin exhibited a tendency to reduce the odor, they were not as effective as zeolite13x and chitosan. On the other hand, commercial surfactants such as benzalkonium chloride and sodium dodecyl sulfate cannot serve as odor‐reducing substances because of their limited thermal stability. An olfactometry test confirmed that chitosan and carbon black are good odor‐reducing agents. Chitosan and carbon black showed a reinforcing effect on vulcanized rubber, whereas the surfactant deteriorated the strength of the rubber composite. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2253–2260, 2004
Investigation of ZnO‐release behavior of poly(N‐isopropylacrylamide‐co‐maleic acid)/ZnO composite hydrogels by differential pulse polarography
Authors: İnam Recai , Çaykara Tuncer , Akkoç Sibel , Kantoğlu Ömer
Published: April 2004

Poly(N‐isopropylacrylamide‐co‐maleic acid)‐zinc oxide [P(NIPA/MA)/ZnO] composite hydrogels, containing a definite amount of ZnO, were prepared from N‐isopropylacrylamide (NIPA) and maleic acid (MA) monomers with 0–31.15 mol % MA in aqueous saturated zinc oxide solutions by radiation‐induced polymerization and gelation using γ rays from a 60Co source. The amounts of released ZnO from these composite hydrogels were determined by differential pulse polarography (DPP) using the characteristic peaks obtained at about –1,000, −1,050, and –1,300 mV at pH 2.0, 5.5, and 7.05, respectively. It was found that the ZnO‐release behavior of P(NIPA/MA)/ZnO composite hydrogels depended strongly on the MA content and pH of the medium.
The study of poly(styrene‐co‐p‐(hexafluoro‐2‐hydroxylisopropyl)‐α‐methylstyrene)/poly(ethylene oxide) blends
Authors: Chen Shiming , Qiu Furong , Tan Li
Published: April 2004

Different hydroxyl content poly(styrene‐co‐p‐(hexafluoro‐2‐hydroxylisopropyl)‐α‐methylstyene) [PS(OH)‐X] copolymers were synthesized and blends with 2,2,6,6‐tetramrthyl‐piperdine‐1‐oxyl end spin‐labeled PEO [SLPEO] were prepared. The miscibility behavior of all the blends was predicted by comparing the critical miscible polymer–polymer interaction parameter (χcrit) with the polymer–polymer interaction parameter (χ). The micro heterogeneity, chain motion, and hydrogen bonding interaction of the blends were investigated by the ESR spin label method. Two spectral components with different rates of motion were observed in the ESR composite spectra of all the blends, indicating the existence of microheterogeneity at the molecular level. According to the variations of ESR spectral parameters Ta, Td, ΔT, T50G and τc, with the increasing hydroxyl content in blends, it was shown that the extent of miscibility was progressively enhanced due to the controllable hydrogen bonding interaction between the hydroxyl in PS(OH) and the ether oxygen in PEO. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2312–2317, 2004
Microwave‐assisted synthesis of high‐molecular‐weight poly(ether imide)s by phase‐transfer catalysis
Authors: Gao Changlu , Zhang Suobo , Gao Lianxun , Ding Mengxian
Published: April 2004

A facile and rapid polycondensation reaction of disodium bisphenol A with bis(chlorophthalimide)s was preformed with a domestic microwave oven in o‐dichlorobenzene by phase‐transfer catalysis. The polymerization reactions, in comparison with conventional heating polycondensation, proceeded rapidly and were completed within 25 min. The polymerizations gave the corresponding poly(ether imide)s with inherent viscosities of 0.55–0.92 dL g−1. The effects of various factors on the polymerization, such as the amount of the catalyst, the reaction time, and the microwave power were studied. The properties of the polymers were briefly characterized. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2415–2419, 2004
Kinetics of polymerization of dimer fatty acids with ethylenediamine
Authors: Heidarian Javad , Ghasem Nayef Mohd , Wan Daud Wan Mohd Ashri
Published: April 2004

A generally applicable stoichiometric and kinetic model was developed for the polymerization of dimer fatty acids with ethylenediamine. The rate equations were second‐order before 90% conversion and were used between 405 and 475 K. The parameters of the rate equations were determined with nonlinear regression analysis. A comparison of the model predictions and the experimental data showed that the approach was useful in predicting the polymerization kinetics. The equilibrium constant changed from 3.175 to 7.311. The frequency factor and activation energy for the forward rate constant before 90% conversion were 2,716,894 kg mol−1 min−1 and 66.7 kJ mol−1, respectively. The equilibrium constant was independent of the temperature at frequency factor and activation energy values of 74.4 and 9.7 kJ mol−1, respectively. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2504–2513, 2004
Effect of poly(propylene carbonate) on the crystallization and melting behavior of poly(β‐hydroxybutyrate‐co‐β‐hydroxyvalerate)
Authors: Li J. , Lai M. F. , Liu J. J.
Published: April 2004

The crystallization and melting behavior of poly(β‐hydroxybutyrate‐co‐β‐hydroxyvalerate) (PHBV) and a 30/70 (w/w) PHBV/poly(propylene carbonate) (PPC) blend was investigated with differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR). The transesterification reaction between PHBV and PPC was detected in the melt‐blending process. The interaction between the two macromolecules was confirmed by means of FTIR analysis. During the crystallization process from the melt, the crystallization temperature of the PHBV/PPC blend decreased about 8°C, the melting temperature was depressed by 4°C, and the degree of crystallinity of PHBV in the blend decreased about 9.4%; this was calculated through a comparison of the DSC heating traces for the blend and pure PHBV. These results indicated that imperfect crystals of PHBV formed, crystallization was inhibited, and the crystallization ability of PHBV was weakened in the blend. The equilibrium melting temperatures of PHBV and the 30/70 PHBV/PPC blend isothermally crystallized were 187.1 and 179°C, respectively. The isothermal crystallization kinetics were also studied. The fold surface free energy of the developing crystals of PHBV isothermally crystallized from the melt decreased; however, a depression in the relative degree of crystallization, a reduction of the linear growth rate of the spherulites, and decreases in the equilibrium melting temperature and crystallization capability of PHBV were detected with the addition of PPC. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2514–2521, 2004
Frictional study of woven fabrics: The relationship between the friction and velocity of testing
Authors: Hermann D. , Ramkumar S. S. , Seshaiyer P. , Parameswaran S.
Published: April 2004

A simple friction factor has been devised to characterize the frictional properties of textile materials. The friction factor enables universal comparisons among different textile materials. A poly(methyl methacrylate) sled has been used as a standard friction substrate to characterize the friction of a woven cotton fabric. The influence of the velocity of testing on the frictional characteristics has been studied in detail with the novel friction factor. This study elaborates the relationship between the speed of testing and the new fabric friction factor. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2420–2424, 2004
Mechanical and dynamical mechanical properties of chloroprene rubber and cellulose II composites
Authors: Martins Agnes F. , de Meneses Sergio M. , Visconte Leila L. Y. , Nunes Regina C. R.
Published: April 2004

Vulcanized composites of chloroprene rubber (CR) with cellulose II (Cel II) as a filler were investigated. Cel II, obtained by the coagulation of cellulose xanthate, was incorporated in the rubber by the traditional method. The filler content varied from 0 to 30 phr. For comparison purposes, carbon black (CB)–CR composites were also studied. The CB amount varied from 0 to 45 phr. The mechanical and dynamic mechanical properties were determined, and the CR composite containing 20 phr of Cel II showed the best set of properties. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2425–2430, 2004
Oxygen permeation resistance of polyethylene, polyethylene/ethylene vinyl alcohol copolymer, polyethylene/modified ethylene vinyl alcohol copolymer, and polyethylene/modified polyamide–ethylene vinyl alcohol copolymer bottles
Authors: Yeh Jen‐Taut , Huang Shyh‐Shiuan , Yao Wei‐Hua , Wang Ing‐Jing , Chen Cheng‐Chi
Published: April 2004

The oxygen permeation resistance of polyethylene (PE), polyethylene/ethylene vinyl alcohol copolymer (PE/EVOH), polyethylene/modified ethylene vinyl alcohol copolymer (PE/MEVOH), and polyethylene/modified polyamide–ethylene vinyl alcohol copolymer (PE/MPAEVOH) bottles was investigated. The oxygen permeation resistance improved significantly after the blending of ethylene vinyl alcohol copolymer (EVOH) barrier resins in PE matrices during blow molding; less demarcated EVOH laminas were found on the fracture surfaces of the PE/EVOH bottles. Surprisingly, the oxygen permeation resistance of the PE/MEVOH bottles decreased significantly, although more clearly defined modified ethylene vinyl alcohol copolymer (MEVOH) laminas were found for the PE/MEVOH bottles as the compatibilizer precursor contents present in the MEVOH resins increased. In contrast, after the blending of modified polyamide (MPA) in EVOH resins, more demarcated modified polyamide–ethylene vinyl alcohol copolymer (MPAEVOH) laminar structures were observed in the PE/MPAEVOH bottles as the MPA contents present in the MPAEVOH resins increased. In fact, with proper MPAEVOH compositions, the oxygen permeation resistance of the PE/MPAEVOH bottles was even better than that of the PE/EVOH bottles. These interesting oxygen barrier and morphological properties of the PE, PE/EVOH, PE/MEVOH, and PE/MPAEVOH bottles were investigated in terms of the free volumes, barrier properties, and molecular interactions in the amorphous‐phase structures of the barrier resins present in their corresponding bottles. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2528–2537, 2004
Compatibilization efficiency of styrene–butadiene triblock copolymers in polystyrene–polypropylene blends with varying compositions
Authors: Hlavatá D. , Hromádková J. , Fortelný I. , Hašová V. , Pulda J.
Published: April 2004

The compatibilization efficiency of two styrene‐butadiene‐styrene triblock copolymers with short (SB1) and long (SB2) styrene blocks was studied in polystyrene (PS)–polypropylene (PP) blends of composition 20, 50, and 80 wt % PS. The supramolecular structure of the blends was determined by small‐angle X‐ray scattering, and the morphology was studied with transmission electron microscopy and scanning electron microscopy. Structural changes in both the uncompatibilized and compatibilized blends were correlated with the values of tensile impact strength of these blends. Even though the compatibilization mechanisms were different in blends with SB1 and SB2, the addition of the block copolymers to the PS–PP 4/1 and PS–PP 1/4 blends led to similar structures and improved the mechanical properties in the same way. These block copolymers had a very slight effect on the impact strength in PS–PP 1/1 blends, exhibiting a nearly cocontinuous phase morphology. The strong migration of SB2 copolymers to the interface and of SB1 copolymers away from the interface were detected during the annealing of compatibilized PS–PP 4/1 blends. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2431–2441, 2004