bluuebunny/crossref_metadata_2025 huggingface dataset:
Monazite Breakdown in Metapelites From Wedel Jarlsberg Land, Svalbard — Preliminary Report
Authors: Majka Jarostaw , Budzyń Bartosz
Published: March 2007

Monazite Breakdown in Metapelites From Wedel Jarlsberg Land, Svalbard — Preliminary Report

Metapelites from the SW part of Wedel Jarlsberg Land were progressively metamorphosed under amphibolite facies conditions followed by a Caledonian low-temperature metamorphic event under greenschist facies conditions. The latter resulted in various stages of monazite breakdown. These include monazite alterations and the formation of allanite-apatite coronas.
New Occurrence of Clausthalite (PbSe) in the Sudetes (SW Poland)
Authors: Muszer Antoni , Szuszkiewicz Adam , Łobos Krzysztof
Published: March 2007

New Occurrence of Clausthalite (PbSe) in the Sudetes (SW Poland)

The presence of clausthalite in the area of old mining works near Dziećmorowice in the Sowie Mts (SW Poland) is reported here for the first time. The identification of the clausthalite is based on macro- and microscopic observations, reflectance measurements, chemical analyses and X-ray diffraction data. The clausthalite, together with uraninite, forms veinlets in a breccia comprising <50% calc-silicate rock fragments. Different polishing hardnesses suggest some variation in the mineral structure of individual clausthalite grains. Chemical spot analyses do not reveal elements other than Pb and Se though calculated unit-cell parameters may suggest minor substitution of S for Se.
Dendrochronological Dating of Icons from the Museum of the Folk Building in Sanok
Authors: Krąpiec Marek , Barniak Joanna
Published: March 2007

Dendrochronological analysis was carried out for 13 historic icons from the collection of the Museum of the Folk Building in Sanok, painted on fir and spruce boards. Eleven sequences of the annual growth rings produced from the analysed fir boards were absolutely dated against the fir dendrochronological standard for S Poland, constructed by E. Szychowska-Krąpiec. Most of the analysed objects date back to the seventeenth and eighteenth centuries, only one board was dated to the midnineteenth century. The dendrochronological analyses carried out prove broad possibilities of dating objects of the iconographic art painted on panels from fir wood, originating from south-eastern Poland and adjacent areas.
Anomalous Fading of Ir-Stimulated Luminescence from Feldspar Minerals: Some Results of the Study
Authors: Molodkov Anatoly , Jaek Ivar , Vasilchenko Valery
Published: March 2007

An increasing amount of evidence shows that the use of feldspars in luminescence dating may suffer from significant age underestimates, which are thought to result from anomalous fading. In the hope of finding a solution to the problem we undertook physical investigations of kinetics and temperature dependencies of tunnel afterglow of these minerals. As a result, the method of the direct detection of the tunnel transitions from the dosimetric traps is proposed. Some other relevant results obtained are also presented and discussed. Particularly, the probable reasons of absence of effects of anomalous fading in the feldspar samples investigated in the present work are elucidated.
Local Chronologies and Regional Diversity of Dendrochronological Signal of Douglas Fir in Poland
Authors: Wilczyński Sławomir , Feliksik Edward
Published: March 2007

In Poland, 50 sites of Douglas fir were selected for which tree-ring chronologies were computed. Douglas fir in different parts of Poland has a specific increment rhythm, on the basis of which the four homogeneous dendrochronological zones were distinguished. The first zone (I) comprises Pomerania, Baltic coast, Warmia, and Mazuria (lowlands of northern Poland), the second zone (II) - Great Poland, Lower Silesia (lowlands of central Poland), the third zone (III) - the Sudetes and the Carpathian mountains, and the fourth zone (IV) - foothills of the Carpathians Mts., Roztocze, and the Świętokrzyskie Mts. (uplands of southern Poland). These areas are called the dendroclimatic zones because different thermo-pluvial conditions of the summer season were a cause of diversification of the Douglas fir increment rhythm, and in consequence of its chronology. A high similarity of site chronologies of a given region permitted to construct regional tree-ring chronologies for respective zones. Thermal conditions of the winter season (February - March) were the factor most strongly and similarly affecting radial increment of Douglas fir populations in the entire territory of Poland. This factor caused that all chronologies showed many similar traits in their progress. This fact permitted to construct the supra-regional (all-Polish) tree-ring chronology for this tree species. It comprises the period from 1900 to 2000, and it is a good standard for dating Douglas fir wood samples originating from the area of Poland.
Determination of the Initial 137Cs Fallout on the Areas Contaminated by Chernobyl Fallout
Authors: Poręba Grzegorz , Bluszcz Andrzej
Published: March 2007

The fallout radioisotope 137Cs is widely used to study rates and patterns of soil redistribution. This method requires the knowledge about the initial fallout of cesium in the study area. This paper describes the method of establishing the initial fallout of cesium for a study area which is contaminated by Chernobyl fallout. The study was carried out on the loess area near the Ujazd village (South-West Poland). The 137Cs activities for reference soil cores varied from 4.41(24) kBq/m2 to 5.97(26) kBq/m2. The average value of the reference inventory of 137Cs for the study area is 5.23(15) kBq/m2. The calculated contribution of the Chernobyl 137Cs fallout in the total cesium is equal 69%. Moreover the annual values of the 137Cs fallout based on the precipitation data were calculated and presented. This study provides the method of calculating the 137Cs fallout connected with the nuclear weapon testing based on the precipitation data. Moreover, this study also indicated that the spatial variability on the highly contaminated by Chernobyl cesium study area is small (RSD about 10%) and thus it is possible to use the cesium method to study soil redistribution.
Issue of Actual Chronology of a Romanesque Chapel at the Wlen Castle (Lower Silesia, Poland) in the Light of Mortar Radiocarbon Dating
Authors: Michniewicz Jacek , Nawrocka Danuta , Pazdur Anna , Żurakowska Marta
Published: March 2007

The presented work discusses results of radiocarbon dating of lime mortars sampled from walls of a Romanesque chapel at the Wleń castle. Considering a homogeneous structure of the mortars, an attempt to determine the chronology was made. Radiocarbon dating was carried out both on carbonate binders and laboratory-selected charcoals from the mortars. According to obtained data, charcoal ages are older than the age of the binders. Assuming the 12th century chronology of the chapel's erection to be correct, it was found that the applied method did not provide the result which is consistent with archaeological estimations.
Design and characterization of chitosan-containing mucoadhesive buccal patches of propranolol hydrochloride
Authors: Patel Vishnu , Prajapati Bhupendra , Patel Madhabhai
Published: March 2007

Design and characterization of chitosan-containing mucoadhesive buccal patches of propranolol hydrochloride

Mucoadhesive buccal patches containing propranolol hydrochloride were prepared using the solvent casting method. Chitosan was used as bioadhesive polymer and different ratios of chitosan to PVP K-30 were used. The patches were evaluated for their physical characteristics like mass variation, drug content uniformity, folding endurance, ex vivo mucoadhesion strength, ex vivo mucoadhesion time, surface pH, in vitro drug release, and in vitro buccal permeation study. Patches exhibited controlled release for a period of 7 h. The mechanism of drug release was found to be non-Fickian diffusion and followed the first-order kinetics. Incorporation of PVP K-30 generally enhanced the release rate. Swelling index was proportional to the concentration of PVP K-30. Optimized patches (F4) showed satisfactory bioadhesive strength of 9.6 ± 2.0 g, and ex vivo mucoadhesion time of 272 minutes. The surface pH of all patches was between 5.7 and 6.3 and hence patches should not cause irritation in the buccal cavity. Patches containing 10 mg of drug had higher bioadhesive strength with sustained drug release as compared to patches containing 20 mg of drug. Good correlation was observed between the in vitro drug release and in vitro drug permeation with a correlation coefficient of 0.9364. Stability study of optimized patches was done in human saliva and it was found that both drug and buccal patches were stable.
Formulation of a self-emulsifying system for oral delivery of simvastatin: In vitro and in vivo evaluation
Authors: Patil Pradeep , Patil Vandana , Paradkar Anant
Published: March 2007

Formulation of a self-emulsifying system for oral delivery of simvastatin: In vitro and in vivo evaluation

The objective of the present work was to formulate a self-emulsifying drug delivery system (SEDDS) for simvastatin, which is widely used in the treatment of hypercholesterolemia and dyslipidemia as an adjunct to diet. Simvastatin SEDDS were formulated using a 1:1 (V/V) mixture of diesters of caprylic/capric acids and polyglycolyzed glycerides with varying concentrations of polyoxy castor oil and C8/C10 mono-/diglycerides. The developed SEDDS were evaluated for turbidimetry, droplet size analysis, drug content and in vitro diffusion profiles. In vivo performance of the optimized formulation was evaluated in rats using pharmacodynamic marker parameters like plasma total cholesterol (CH), triglycerides (TG) and high-density lipoprotein (HDL-CH) for 21 days. SEDDS containing 9.1% (m/m) simvastatin and 23.0% (m/m) of each excipient showed minimum mean droplet size (124 nm) and optimal drug diffusion. This test formulation showed significant reduction in plasma CH and TG (around 5-fold and 4-fold, respectively), while HDL-CH concentration was markedly higher (2-fold) compared a reference simvastatin suspension formulation after oral administration for 21 days of study. Test formulation has shown enhanced pharmacodynamic performance compared to reference formulation in rats. The study illustrated the potential of simvastatin SEDDS for oral administration and its biopharmaceutic performance.
Multiobjective optimization of semibatch reactive crystallization processes
Authors: Sarkar Debasis , Rohani Sohrab , Jutan Arthur
Published: March 2007

The determination of the optimal feed profiles for a reactive crystallizer is an important dynamic optimization problem, as the feed profiles offer a significant control over the quality of the product crystals. Crystallization processes typically have multiple performance objectives and optimization using different objective functions leads to significantly different optimal operating conditions. Therefore, a multiobjective approach is more appropriate for optimization of these processes. The potential for multiobjective optimization approach is demonstrated for semibatch reactive crystallization processes. The multiobjective approach usually gives rise to a set of optimal solutions, largely known as Pareto‐optimal solutions. The Pareto‐optimal solutions can help the designer visualize the trade‐offs between different objectives, and select an appropriate operating condition for the process. A well known multiobjective evolutionary algorithm, the elitist nondominated sorting genetic algorithm, has been adapted to illustrate the potential for the multiobjective optimization approach. © 2007 American Institute of Chemical Engineers AIChE J, 2007
Chemical Approaches to Molecular Logic Elements for Addition and Subtraction
Authors: Pischel Uwe
Published: March 2007

Molecular and supramolecular logic gates are candidates for computation at the nanoscale level. Nowadays all common logic operations can be mimicked with molecular devices based on chemical approaches. One step further towards molecular systems with increased logic capabilities is the addition or subtraction of binary digits. This Minireview describes recent developments to attain this goal, including bioinspired systems based on DNA and enzymes. Furthermore, chemical molecular logic gates are discussed and compared critically with regard to alternative concepts.
Effect of both uncoated and coated calcium carbonate on fracture toughness of HDPE/CaCO3 nanocomposites
Authors: Sahebian S. , Zebarjad S. M. , Sajjadi S. A. , Sherafat Z. , Lazzeri A.
Published: March 2007

The main goal of this research is to investigate the effect of nano‐CaCO3 coated with different content of stearic acid on fracture toughness of HDPE/CaCO3 nanocomposite. For this purpose, HDPE/10 vol % CaCO3 nanocomposites were made using a twin‐screw mixer–single‐screw extruder. Nanocomposite standard samples were prepared via injection molding method. Three‐point bending tests and microscopic evaluations were performed. The results of fracture toughness test showed that the addition of uncoated nano‐CaCO3 to HDPE causes to decrease fracture toughness, but it can be increased slightly as stearic acid content added. Also the results showed that the stress whitening zone width depends strongly on both CaCO3 and stearic acid content. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3688–3694, 2007
Synthesis and properties of low‐color polyimide/silica hybrid films
Authors: Yang Chin‐Ping , Su Yu‐Yang , Hsiao Sheng‐Huei
Published: March 2007

A series of polyimide precursors, poly(amic acid)s, containing propyltrimethoxysliane at two chain ends were prepared from 4,4′‐bis(4‐amino‐2‐trifluoromethylphenoxy)biphenyl (I) with six commercially available dianhydrides, followed by end‐capping with 3‐aminopropyltrimethoxysilane (APrTMOS). A new class of fluorine‐containing polyimide/silica composite films (III) with chemical bonds between the fluorinated polyimide backbone and the silica network has been synthesized from the APrTMOS‐terminated precursors with tetramethoxysilane via the sol‐gel process and thermal cyclodehydration. The resultant hybrid films were light‐colored, flexible, and tough. They had high levels of thermal stability associated with high glass‐transition temperatures (>251°C), 10% weight‐loss temperatures in excess of 527°C, and char yields at 800°C in nitrogen higher than 60%. For a comparative study, the analogous nonfluorinated polyimide/silica hybrid films (III′), based on 4,4′‐bis(4‐aminophenoxy)biphenyl (I′), and the neat fluorinated polyimide films (IV), based on diamine I, were also synthesized and characterized. The hybrid films of the fluorinated series III showed a higher transparency and less color intensity when compared with the nonfluorinated III′ analogs. They also revealed a lower refraction index and birefringence than pure polyimides (IV). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 4046–4052, 2007
Preparation of poly(phthalazinone ether sulfone ketone) hollow fiber membrane for gas separation
Authors: Fu Haitao , Yang Daling , Zhang Shouhai , Jian Xigao
Published: March 2007

Poly(phthalazinone ether sulfone ketone) (PPESK) asymmetric hollow fiber membranes for gas separation were prepared by dry/wet phase inversion technique. The effects of various preparation conditions such as solvent, nonsolvent‐additives(NSA), PPESK concentration, and air gap on the membrane performance were studied. The heat resistance of the PPESK hollow fiber membrane was also examined. The hollow fiber membrane prepared from solvent with stronger solubility showed low gas permeation and high O2/N2 selectivity due to the denser skin layer. Hollow fiber membrane made from PPESK/DMAc/EtOH/THF system had thicker skin layer than that made from PPESK/DMAc/GBL system with the same ratio of near‐to‐cloud‐point of NSA, which resulted in the higher O2/N2 selectivity. Along with the increase of NSA content, the gas permeation increased and the O2/N2 selectivity decreased. The O2/N2 selectivity of hollow fiber membranes made from PPESK/DMAc/GBL and PPESK/DMAc/EtOH/THF systems were 4.9 and 4.8 respectively, when the membrane forming systems contained appropriate content of NSA. The high polymer concentration resulted in low gas permeation and high O2/N2 selectivity. When the air gap was excessively long, the membrane performance dropped because of the damage to the dense skin layer. There was no significant drop on the membrane performance when the operation temperature was elevated to 90°C. The average O2/N2 selectivity was higher than 3.0 at 70°C during a long period of 55 days' test time. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Flexible composite of PEEK and liquid crystalline polymer in presence of polyphosphazene
Authors: Rath T. , Kumar S. , Mahaling R. N. , Mukherjee M. , Das C. K. , Pandey K. N. , Saxena A. K.
Published: March 2007

Binary blends of a reactive ketone based polymer with liquid crystalline polymer (LCPA‐950) were studied. The main properties required are flexibility and thermal resistance of material in presence of polyphosphazene, which acts as a compatibilizer. It has been observed that with the addition of LCP the composites showed reduced viscosity during blending and changes in the crystallization of the LCP phase. FTIR study showed that there was a partial interaction between the PEEK and LCP in presence of polyphosphazene. Polyphosphazene is miscible with both PEEK and LCP, which was evident from DMA results. The thermal stability of the composites has been studied by DTA/TGA. The thermal analysis of the blends showed that the degradation process is accelerated by blending, but with the addition of polyphosphazene the onset temperature of first degradation slightly shifted towards higher side than the PEEK/LCP blend. Measurement of the tensile properties showed an increase in the elongation as well as enhanced modulus and strength. From SEM micrographs of tensile fractured surfaces, it was revealed that there is good adhesion between the matrix and dispersed phase upon addition of polyphosphazene to ketone based polymer (PEEK) with LCP. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3758–3765, 2007
Rheology and relaxation processes in a melting thermotropic liquid–crystalline polymer
Authors: Yu Ruobing , Yu Wei , Zhou Chixing , Feng J. J.
Published: March 2007

The relaxation behavior of a thermotropic liquid–crystalline polymer (TLCP), LC‐5000 from Unichika, Japan, was investigated by rheology and optical microscopy. The solid‐nematic transition was shown by DSC and dynamic temperature ramp. The transitions of dynamic modulus with temperature correspond to the end of the melting process. The TLCP is composed of unmelted solid crystals and nematic liquid crystal during the melting process. Macroscopically, it changes from a viscoelastic solid to a viscoelastic liquid in this process, as verified by creep test and dynamic frequency sweep under different temperature. The relaxation spectra of the TLCP under different temperature were calculated from the dynamic modulus. The characteristic relaxation processes determined from the relaxation spectrum are consistent with the observation from polarized optical microscopy. During melting, in particular, the relaxation of deformed polydomains and chain orientation slows down due to the constraining effects of unmelted solid crystals. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3780–3787, 2007
Synthesis and characterization of epoxy film cured with phosphorous‐containing phenolic resin
Authors: Xia Xin‐Nian , Xiong Yuan‐Qin , Zhang Xiao‐Hua , Xu Wei‐Jian , Yu Jun‐Hui
Published: March 2007

Through the electrophilic addition reaction of P(O)H and CC, a series of novel phosphorus‐containing phenolic resins bearing maleimide (P‐PMFs) were synthesized and used as curing agent for preparing high performance and flame retardancy epoxy resins. The structure of the resin was confirmed with FTIR and elemental analysis. Thermal properties and thermal degradation behaviors of the thermosetted resin was investigated by using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The epoxy resins exhibited high glass transition temperature (143–156°C), goof thermal stability (>330°C) and retardation on thermal degradation rates. High char yields (700°C, 52.9%) and high limited oxygen indices (30.6–34.8) were observed, indicating the resins' good flame retardance for the P‐PMFs/CNE cured resins. The developed resin may be used potentially as environmentally preferable products in electronic fields. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3813–3817, 2007
Unique aerodynamically driven methodology for forming droplets, threads to scaffolds
Authors: Arumuganathar S. , Jayasinghe S. N. , Suter N.
Published: March 2007

Jet‐based methodologies for forming droplets and threads leading to the fabrication of scaffolds are playing a pivotal role in materials science and engineering. These techniques are essentially interfacing engineering with the biological sciences. There are several routes for forming droplets, which are subsequently deposited with precision, namely, ink‐jet printing to electrospraying. Fabricating threads/fibers sized from the nano‐ to the micrometer range are generally carried out by means of electrospinning. These three processes are well‐established and have been explored to a great extend. In this article, we have shown a unique processing technology completely driven by a pressure difference over an orifice possessing the ability to form droplets, threads to scaffolds. Hence, this process now joins the microfabrication race alongside its competing technologies, in the hope to undergo a rapid developmental program arming itself for competing with its rival technologies. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3844–3848, 2007
Nonisothermal cure kinetics of diglycidylether of bisphenol‐A/amine system reinforced with nanosilica particles
Authors: Ghaemy M. , Nasab S. M. Amini , Barghamadi M.
Published: March 2007

Epoxy‐silica nanocomposites were obtained from directly blending diglycidylether of bisphenol‐A (DGEBA)‐based epoxy and nanoscale silica (NS) and then curing with 4,4′‐diaminodiphenylamine (DDA). The effect of amount of nanosilica (NS) particles as catalyst on the mechanism and kinetic parameters of cure reaction of DGEBA/DDA system was studied. The kinetics parameters were obtained from nonisothermal differential scanning calorimeter (DSC) data using the Kissinger and Ozawa equations. The exothermic peak was shifted toward lower temperatures in DGEBA/DDA/NS system with increasing the amount of nanoslica particles. However, the existence of NS particles with hydroxyl groups in the structure in the mixture of DGEBA/DDA catalyzes the cure reaction and increases the rate constant. The activation energy of cure reaction of DGEBA/DDA system obtained from two methods were in good agreement, and showed a decrease when NS particles were present in the mixture. The mechanism of reaction of DGEBA with DDA was carried out by isothermal curing in the oven at 130°C and measuring the disappearance peak of epoxide group at 916 cm−1 using FTIR. The diffusive behavior of two systems was investigated during water sorption at 25°C and the experimental results fitted well to Fick's law. Diffusion coefficient of cured sample from DGEBA/DDA/10% NS blend decreased in comparison with the sample without NS particles. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3855–3863, 2007
Diffusivity of ethylene and propylene in atactic and isotactic polypropylene: Morphology effects and free‐volume simulations
Authors: Gonzalez A. , Eceolaza S. , Etxeberria A. , Iruin J. J.
Published: March 2007

Diffusion coefficients of propylene and ethylene through particles and films of isotactic polypropylene (iPP) as well as through films of atactic, completely amorphous, polypropylene have been measured by gravimetric experiments. iPP particles with relatively similar crystallinities but with different particle size distributions (PSD), and different origins have been used. They exhibited very different diffusion coefficients when the average radius of the PSD was used as the dimensional parameter of the diffusion process. However, films prepared with these particles and having similar crystallinities provided similar diffusion coefficients. The results are consistent with the idea of a multigrain structure in the particles, where the apparent (or experimental) diffusion coefficient is a consequence of the complex system formed by internal and external areas. The diffusion coefficient of the films, taken as the real diffusion magnitude, can be used in the calculation of the true diffusional radius of these multigrain particles. Experimental results of the diffusion coefficients have been reasonably well reproduced with the aid of the Vrentas‐Duda free volume model. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3871–3878, 2007
Effect of dispersion state of organoclay on cellular foam structure and mechanical properties of ethylene vinyl acetate copolymer/ethylene‐1‐butenecopolymer/organoclay nanocomposite foams
Authors: Park Keun‐Wan , Ray Chowdhury Subhendu , Park Cha‐Cheol , Kim Gue‐Hyun
Published: March 2007

In this study, our goal is to obtain lower density of ethylene‐vinyl acetate copolymer (EVA)/ethylene‐1‐butene copolymer (EtBC) foams without sacrificing mechanical properties. For this purpose EVA/EtBC/organoclay (Cloisite 15A, Closite 30B) nanocomposite foams were prepared. To investigate the effect of compatibilizer on the dispersion state of organoclay in cellular foam structure and mechanical properties of the EVA/EtBC/organoclay foams composites were prepared with and without maleic anhydride grafted EtBC (EtBC‐g‐MAH). The dispersion of organoclay in EVA/EtBC/organocaly foams was investigated by X‐ray diffraction and transmission electron microscopy. The EVA/EtBC nanocomposite foamswith the compatibilzer, especially EVA/EtBC/Cloisite 15A/EtBC‐g‐MAH foams displayed more uniform dispersion of organoclay than EVA/EtBC nanocomposite foams without the compatibilzer. As a result, EVA/EtBC/Cloisite 15A/EtBC‐g‐MAH foams have the smallest average cell size and highest 100% tensile modulus followed by EVA/EtBC/Cloisite 30B/EtBC‐g‐MAH foams. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3879–3885, 2007
Properties of dynamically vulcanized ethylene–propylene–diene copolymer/polypropylene blends
Authors: Taşdemir Münir , Topsakaloğlu Murat
Published: March 2007

In this study, vulcanized thermoplastic elastomers were produced through the formation of crosslinks with peroxide for different ratios of ethylene–propylene–diene copolymer to polypropylene. Mixing was performed with a twin‐screw extruder. Afterward, the yield, tensile strength, elastic modulus, elongation, Izod impact strength, hardness, melt flow index, Vicat softening point, heat deflection temperature, and density of the crosslinks were determined. The thermal transition temperatures and microstructure were determined with differential scanning calorimetry and scanning electron microscopy, respectively. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3895–3902, 2007
Effect of ionomer on clay dispersions in polypropylene‐layered silicate nanocomposites
Authors: Liu Hongzhi , Tag Lim Hyung , Hyun Ahn Kyung , Jong Lee Seung
Published: March 2007

In this study, polypropylene (PP)/clay nanocomposites containing different concentrations of ethylene‐methacrylic acid ionomer (i.e. Surlyn®) were prepared, and the effect of ionomer on clay dispersion was studied via WAXD, rheology, SEM, and TEM. The role of the ionomer in the nanocomposites was compared with that of maleic anhydride grafted PP (PP‐g‐MA), which has been widely used as a compatibilizer in making PP/clay nanocomposites. With an increase in the concentration of compatibilizer, the position of d001 peak of OMMT shifted toward a lower angle for PP‐g‐MA system, while the position remained almost unchanged for Surlyn system, in which a larger interlayer spacing (d001) was found with respect to the former. In rheology, the addition of the ionomer led to a gradual increase in both moduli and complex viscosity, and the nonterminal behavior at low frequency was observed in both systems. In addition, the ternary hybrid containing 20 wt % Surlyn achieved the largest enhancement in relative viscosity, which was more than that of the nanocomposite prepared from pure Surlyn or pure PP, presumably indicative of the existence of strong interaction between the components. Finally, SEM and TEM micrographs demonstrated that exfoliated structure was preferred for PP/Surlyn/OMMT hybrids, while intercalated morphology for PP/PP‐g‐MA/OMMT. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 4024–4034, 2007
Preparation and properties of iodine‐doped radiopaque natural rubber
Authors: Nisha V. S , Rani Joseph
Published: March 2007

Polymers exhibit low electron density and they are radiolucent. Polymers can be made radiopaque by different techniques. We report a method for the preparation of radiopaque material from natural rubber (NR). NR in its latex form was iodinated. Iodinated natural rubber (INR) was characterized by using UV, thermo gravimetric analysis (TGA), and X‐ray images. INR was compounded at high and low temperatures and its physical properties were measured. The low temperature cured samples show good radiopacity and conductivity. The optical density of low temperature cured samples was measured. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Allylated novolac/4,4′‐bismaleimidodiphenylmethane resin containing polyhedral oligomeric silsesquioxane: Preparation, morphology and thermal stability
Authors: Li Wanwan , Liu Feng , Wei Liuhe , Zhao Tong
Published: March 2007

Allylated novolac/4,4′‐bismaleimidodiphenylmethane resin (AN/BDM) had been modified with well‐defined inorganic building blocks‐polyhedral oligomeric silsesquioxane (POSS). Octamaleimidophenyl polyhedral silsesquioxane (OMPS) was used as the cocuring reagent of the AN/BDM resin to prepare POSS‐modified AN/BDM resin, and POSS content was between 0 and 17.8 wt %. The curing reaction of the POSS‐modified AN/BDM resin was monitored by means of Fourier transform infrared spectroscopy (FTIR), and the results revealed that maleimide groups on OMPS molecule could undergothe curing reaction between allyl groups and maleimide groups. Therefore, the crosslinked network containing POSS was formed. Scanning electron microscopy (SEM) and X‐ray diffraction (XRD) were employed to study the morphology of the cured POSS‐modified AN/BDM resins. The homogeneous dispersion of POSS cages in AN/BDM matrices was evidenced. Thermogravimetric analysis (TGA) indicated that incorporation of POSS into AN/BDM crosslinked network led to enhanced thermal stability. The improved thermal stability could be ascribed to higher crosslink density and inorganic nature of POSS. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3903–3908, 2007
Effect of polymer–clay interaction on solvent transport behavior of fluoroelastomer–clay nanocomposites and prediction of aspect ratio of nanoclay
Authors: Maiti Madhuchhanda , Bhowmick Anil K.
Published: March 2007

Diffusion and sorption of methyl ethyl ketone and tetrahydrofuran through fluoroelastomer‐clay nanocomposites were investigated in the temperature range of 30–60°C by swelling experiments. Slightly non‐Fickian transport behavior was found for these nanocomposites, having variation of type of nanoclay and loading. Different transport parameters depend on the size and shape of the penetrant molecules. The results were used to study the effect of nanoclay on the solvent transport‐properties of nanocomposites and their interactions with solvents. The diffusion coefficient of methyl ethyl ketone at 30°C for neat rubber was 1.43 × 10−8 cm2 s−1, while those of the unmodified and the modified clay filled samples at 4 phr loading were 0.24 × 10−8 and 0.50 × 10−8 cm2 s−1, respectively. At 8 and 16 phr loading of the unmodified clay, it was found to be 0.44 × 10−8 and 0.64 × 10−8 cm2 s−1, respectively. The samples were also reswelled after deswelling. Surprisingly, transport behavior became Fickian on reswelling. Interestingly, ratio of diffusion coefficients of the filled system to the neat system was found to be almost same for the first time swelling and reswelling experiments. The results showed that better polymer‐clay interaction in the case of the unmodified‐clay filled nanocomposites is responsible for enhanced solvent‐resistance property. From the permeation data, for the first time, aspect ratio of nanoclays in different composites was calculated and found to have good correlation with the morphology data obtained from transmission electron microscopy. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Physical properties of water‐blown rigid polyurethane foams from vegetable oil‐based polyols
Authors: Tu Yuan‐Chan , Kiatsimkul Pimphan , Suppes Galen , Hsieh Fu‐Hung
Published: March 2007

Fifty vegetable oil‐based polyols were characterized in terms of their hydroxyl number and their potential of replacing up to 50% of the petroleum‐based polyol in waterborne rigid polyurethane foam applications was evaluated. Polyurethane foams were prepared by reacting isocyanates with polyols containing 50% of vegetable oil‐based polyols and 50% of petroleum‐based polyol and their thermal conductivity, density, and compressive strength were determined. The vegetable oil‐based polyols included epoxidized soybean oil reacted with acetol, commercial soybean oil polyols (soyoils), polyols derived from epoxidized soybean oil and diglycerides, etc. Most of the foams made with polyols containing 50% of vegetable oil‐based polyols were inferior to foams made from 100% petroleum‐based polyol. However, foams made with polyols containing 50% hydroxy soybean oil, epoxidized soybean oil reacted with acetol, and oxidized epoxidized diglyceride of soybean oil not only had superior thermal conductivity, but also better density and compressive strength properties than had foams made from 100% petroleum polyol. Although the epoxidized soybean oil did not have any hydroxyl functional group to react with isocyanate, when used in 50 : 50 blend with the petroleum‐based polyol the resulting polyurethane foams had density versus compressive properties similar to polyurethane foams made from 100% petroleum‐based polyol. The density and compressive strength of foams were affected by the hydroxyl number of polyols, but the thermal conductivity of foams was not. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Characterization and property correlations of amorphous poly(alpha olefin)
Authors: Soo Ha Hyun , Hwan Shin Jung , Kyu Kim Byung
Published: March 2007

Amorphous poly(alpha olefins)® (APAOs) with various types and contents of comonomers, and molecular weight were characterized by general, thermal, rheological, and mechanical methods and their properties were correlated with their molecular parameters. It was found that they can be used as a modifier for isotactic polypropylene. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Transesterification reaction between acetylated wood and trialkoxysilane coupling agents
Authors: Özmen Nilgül , Sami Çetin Nihat , Tingaut Philippe , Sèbe Gilles
Published: March 2007

A novel dibutyltin oxide‐catalyzed transesterification reaction between acetylated maritime pine sapwood (Pinus pinaster Soland) and methyltrimethoxysilane (MTMS) was studied. The transesterification exchange between the acetyl moities and MTMS was confirmed by weight percent gain calculations, Fourier‐transform infrared spectroscopy, as well as solid state 13C and 29Si crosspolarization with magic‐angle spinning nuclear magnetic resonance spectroscopy. The silicon atoms in the MTMS‐transesterified wood were found to exist in the form of more or less condensed structures, concurrently formed by condensation between neighboring Si(OMe)3 groups. An increase in the acetyl/MTMS exchange rate was also noted when the catalyst amount, temperature, or reaction time were increased. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Microcellular foaming of PE/PP blends
Authors: Zhang Ping , Zhou Nan Qiao , Wu Qing Feng , Wang Ming Yi , Peng Xiang Fang
Published: March 2007

Three different polyethylene/polypropylene (PE/PP) blends were microcellular foamed and their crystallinities and melt strengths were investigated. The relationship between crystallinity, melt strength, and cellular structure was studied. Experimental results showed that the three blends had similar variation patterns in respect of crystallinity, melt strength, and cellular structure, and these variation patterns were correlative for each blend. For all blends, the melt strength and PP melting point initially heightened and then lowered, the PP crystallinity first decreased, and then increased as the PE content increased. At PE content of 30%, the melt strength and PP melting point were highest and the PP crystallinity was least. The blend with lower PP crystallinity and higher melt strength had better cellular structure and broader microcellular foaming temperature range. So, three blends had best cellular structure at PE content of 30%. Furthermore, when compared with PE/homopolymer (hPP) blend, the PE/copolymer PP (cPP) blend had higher melt strength, better cellular structure, and wider microcellular foaming temperature range, so it was more suited to be microcellular foamed. Whereas LDPE/cPP blend had the broadest microcellular foaming temperature range because of its highest melt strength within three blends. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 4149–4159, 2007
Compositions based on aromatic polycarbonate and metallic phosphinic acids
Authors: Ozden S. , Shaov A. H. , Charayev A.
Published: March 2007

Four different polymer stabilizers were synthesized from the salt derivatives of phosphinic acids (p‐butoxyphenylcyclohexyl‐phosphinic acid) and potassium, nickel, and two different grades of iron metals. The synthesized stabilizers were introduced into an industrial polycarbonate (PC) and their effects on the mechanical and thermal behavior of PC were investigated. The experiments were carried on following the introduction of the stabilizer into the polymer. The mechanical properties were sensitive to the amount of the stabilizer. Small amounts of potassium increased the breaking stress, the modulus of elasticity, and elongation at break of PC. On the other hand, nickel and iron increased the modulus of elasticity and decreased the breaking stress and elongation at break. The additives negatively affected the thermal properties. This deterioration was caused by the increase of molecular distance between the chains that led to the reduction of polar forces and increased the free volume of the polymer. Heat treatment increased the brittleness and reduced the breaking strength, ductility, and modulus of elasticity of modified PC. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3628–3636, 2007
Novel tin‐coupled star‐shaped medium vinyl butadiene rubber. I. Arm number and its effect on properties
Authors: Lu Jianmin , Zhang Xingying , Zhao Suhe , Yang Wantai
Published: March 2007

To achieve low rolling resistance, high wet grip, and favorable overall performance, star‐shaped medium vinyl butadiene rubber (S‐MVBR) was designed and prepared by “core‐first” method, where novel multifunctional organolithium containing Sn atom as initiator, THF as structure regulator, and carbon–hydrogen compound as solvent. The results showed that coupling reaction between SnCl4 and dilithium is stoichiometrical, and this method has much higher efficiency than the “arm‐first” method. When dilithium is composed of 4–10 repeating units, the average arm number of S‐MVBR is conveniently controlled between 3 and 5 by initiator functionality, which can be easily regulated by the mole ratio of active lithium of dilithium short chain to Cl− in SnCl4. As Sn coupling decreases numbers of noncrosslinking free ends, S‐MVBR has lower rolling resistance, dynamic heating and higher wet grip than linear MVBR. Meanwhile, mechanical properties and processing properties are improved. And the formation of multiarm structure has little effect on viscosity. S‐MVBR with arm number of 3.8 has optimal overall performance. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3917–3923, 2007
Studies on UV‐stable silicone–epoxy resins
Authors: Huang Wei , Zhang Ying , Yu Yunzhao , Yuan Youxue
Published: March 2007

Silicone–epoxy resins were synthesized through hydrosilylation of 1,2‐epoxy‐4‐vinyl‐cyclohexane with 1,3,5,7‐tetramethycyclotetrasiloxane. The silicone–epoxy resins showed high reactivity in the presence of aluminum complex/silanol compound catalysts. Curing of the resins was effected at extremely low concentrations of the aluminum acetylacetonate/Ph2Si(OH)2 catalyst to give hard materials with optical clarity. For the silicone–epoxy resins containing SiH bonds, Al(acac)3 alone is effective for the curing. The cured silicone–epoxy resins showed excellent UV resistance. An improvement in the lifetime of UV‐LEDs was achieved using the silicone–epoxy compositions as encapsulant. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3954–3959, 2007
Synthesis and transport abilities of new membrane materials incorporating bipyrazolic tripods
Authors: Malek Fouad , Ramdani Abdelkrim , Zidane Ismail , Radi Smaail
Published: March 2007

Membrane materials were obtained by photopolymerization reaction of formulation spread over a polyacrylonitrile (PAN) support. The formulation contains the active bipyrazolic tripods monomers, the styrene, and the photostart. The facilitated transport and the extraction power of Cd(II), Pb(II), and Hg(II) through the synthesized membranes were reported. We have determined both the diffusion flux F of different cations and the selectivity S of the prepared membranes towards each cations. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104, 3967–3972, 2007
Blends of thermoplastic polyurethane and polypropylene. I. Mechanical and phase behavior
Authors: Bajsić Emi Govorčin , Šmit Ivan , Leskovac Mirela
Published: March 2007

Pure thermoplastic polyurethane (TPU), polypropylene (PP), and TPU/PP blends with different weight ratios prepared in a twin‐screw extruder were investigated by dynamic mechanical analysis (DMA), the universal tester for mechanical investigation, and by wide‐angle X‐ray diffraction (WAXD). The addition of PP above 20 wt % to the TPU stepwise changed the ductility and Young's modulus, i.e., apparently a kind of ductile → brittle transition occurred between TPU/PP 80/20 and TPU/PP 60/40 blends. This fact and the result of analysis of WAXD curves indicated matrix → dispersed phase inversion in this concentration region. TPU melt enabled easier migration of the PP chains and prolonged crystallization of PP matrix during solidification process affecting thus crystallite size, orientation, and crystallinity. In accordance to this fact, DMA results indicated partial miscibility of PP with polyurethane in the TPU/PP blends due to the lack of interfacial interaction and adhesion between the nonpolar crystalline PP and polar TPU phases. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104, 3980–3985, 2007
The 1st International Conference on Cutting‐Edge Organic Chemistry in Asia
Authors: Isobe Minoru , Chiu Pauline
Published: March 2007

The 1st International Conference on Cutting‐Edge Organic Chemistry in Asia
Cover Picture: Microporous Magnesium and Manganese Formates for Acetylene Storage and Separation (Chem. Asian J. 4/2007)
Authors: Samsonenko Denis G. , Kim Hyunuk , Sun Yinyong , Kim Ghyung‐Hwa , Lee Heung‐Soo , Kim Kimoon
Published: March 2007

Low‐cost and efficient materials that store acetylene with high selectivity are the key to its production, transportation, and delivery. In their Full Paper on page 484 ff., K. Kim and co‐workers demonstrate that microporous magnesium and manganese formates show not only a high capacity for acetylene sorption but also remarkable selectivity over CO2, CH4, N2, O2, and H2 at room temperature. The metal formates discriminate C2H2 and CO2 despite their similar size and physical properties. Single‐crystal X‐ray structure analysis of the acetylene‐adsorbed metal formates reveals two acetylene sorption sites.
Peptides derived from a secretory yeast library restore factor VIII activity in the presence of an inhibitory antibody
Authors: Mersich Christa , Billes Werner , Pabinger Ingrid , Jungbauer Alois
Published: March 2007

The development of autoantibodies against factor VIII represents one of the major complications in the treatment of hemophilia A patients. We have employed a novel library system to obtain peptides that specifically neutralize the interaction between factor VIII and these inhibitors. The random peptides are presented as carboxy‐terminal extensions of the eukaryotic initiation factor 5a, an intracellular protein with a molecular mass of 18 kDa. These random peptides formed an unique binding site, as demonstrated by molecular simulations using the computer programs InsightII and GROMACS. The library was screened to identify peptides binding to the murine monoclonal anti‐factor VIII antibody ESH8 and to inhibitors derived from patients with factor VIII antibodies. Ten peptides binding to ESH8 were identified. Their specificity was confirmed by displacement assays. Two peptides with the sequences STKTLGRPLHGPAGPVEGGALAGVAEDADLVTAVSGR and YHCKREDLTDRDATCALRQPPQAVRGLGPRVTAVSGR showed the ability to restore the factor VIII activity from 33% up to approximately 90% in functional tests performed in vitro. Three candidates for binding to factor VIII antibodies derived from four different patient's sera were achieved. Three fusion proteins with the peptide sequences PQLGSRRSTTPSLTFQNASWFPAGGPCARSNRG, SGSRQVCKLARSLQPF and WERGRRVGAQVRHARHLVARVLDGAGHQARLTAVNGP bound to inhibitors derived from different patients. Furthermore, two of the obtained fusion proteins with the peptide sequences RHWTALGPAPTHTCADLNYPLLS and WERGRRVGAQVRHARHLVARVLDGAGHQARLTAVNGP did also bind to the monoclonal antibody ESH8. This study demonstrates the potential of this system to identify peptides that inhibit the activity of potent inhibitory antibodies and also shows potential as a method for screening of bioactive peptides. Biotechnol. Bioeng. 2007; 98: 12–21. © 2007 Wiley Periodicals, Inc.
Microbial production of hydrogen and ethanol from glycerol‐containing wastes discharged from a biodiesel fuel production plant in a bioelectrochemical reactor with thionine
Authors: Sakai Shinsuke , Yagishita Tatsuo
Published: March 2007

H2 and ethanol production from glycerol‐containing wastes discharged from a biodiesel fuel production plant by Enterobacter aerogenes NBRC 12010 was demonstrated in bioelectrochemical cells. Thionine as an exogenous electron transfer mediator was reduced by E. aerogenes, and was re‐oxidized by a working electrode applied at +0.2 V against a Ag/AgCl reference electrode by a potentiostat (electrode system). At the initial glycerol concentration of 110 mM, 92.9 mM glycerol was consumed in the electrode system with 2 mM thionine after 48 h. On the other hand, the concentration of glycerol consumed was only 50.3 mM under the control conditions without thionine and the electrodes (normal fermentation). There are no differences in the yields of H2 and ethanol against glycerol consumed between the control conditions and the conditions with the electrode system. A pH of 6.0 was suitable for the H2 production in the range between pH 6 and pH 7.5 in the electrode system. At pH values of 7.0 and 7.5, H2 production decreased and formate was remarkably produced in the reaction solution. The rates of both glycerol consumption and the H2 and ethanol production increased as the thionine concentration and the surface area of the working electrode increased. After 60 h, 154 mM of the initial 161 mM glycerol concentration in the wastes was consumed in the electrode system, which is a 2.6‐fold increase compared to the control experiment. Biotechnol. Bioeng. 2007;98: 340–348. © 2007 Wiley Periodicals, Inc.