bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation and characterization of poly(2‐chloroaniline)/SiO2 nanocomposite via oxidative polymerization: Comparative UV–vis studies into different solvents of poly(2‐chloroaniline) and poly(2‐chloroaniline)/SiO2
Authors: Gök Ayşegül , Şen Songül
Published: July 2006

Poly(2‐chloroaniline)/silica (P2ClAn)/SiO2 nanocomposites have been chemically prepared by oxidative polymerization of 2‐chloroaniline in acidic medium containing SiO2. The prepared composites were characterized by FTIR, UV–vis, TGA, XRD, SEM, ESEM, conductivity, and magnetic susceptibility. The incorporation of P2ClAn in composites was endorsed by FTIR studies. The effect of the solution concentration of P2ClAn and P2ClAn/SiO2 prepared in protonated, deprotonated, and reprotonated structures on the UV–vis spectra was investigated into three different solvents (DMF, NMP, and H2SO4). In all forms, the oxidation state of P2ClAn and P2ClAn/SiO2 composite increased with increasing concentration of the testing solution into H2SO4. Thermogravimetric study exhibited that the composite has a higher thermal stability than P2ClAn. XRD measurement of the composite revealed that the crystal structure of incorporated SiO2 undergone a distortion and converted into amorphous. Thus, the XRD pattern of P2ClAn was predominant. SEM analysis results revealed interesting morphological features for the composites converted to different forms and confirmed the formation of monodispersed composite particles. ESEM image of P2ClAn/SiO2 has particle diameter of less than 1 μm. The conductivity of P2ClAn and P2ClAn/SiO2 was measured by four‐probe technique. Magnetic susceptibility measurements revealed that the composite has a paramagnetic properties. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:935–943, 2006
Morphology and melt rheology of nylon 11/clay nanocomposites
Authors: He Xiaofeng , Yang Jun , Zhu Lianchao , Wang Biao , Sun Guangping , Lv Pengfei , Phang In Yee , Liu Tianxi
Published: July 2006

Nylon 11 (PA11)/clay nanocomposites have been prepared by melt‐blending, followed by melt‐extrusion through a capillary. Transmission electron microscopy shows that the exfoliated clay morphology is dominant for low nanofiller content, while the intercalated one is prevailing for high filler loading. Melt rheological properties of PA11 nanocomposites have been studied in both linear and nonlinear viscoelastic response regions. In the linear regime, the nanocomposites exhibit much higher storage modulus (G′) and loss modulus (G″) values than neat PA11. The values of G′ and G″ increase steadily with clay loading at low concentrations, while the G′ and G″ for the sample with 5 wt % clay show an inverse dependence and lie between the modulus values of the samples with 1 and 2 wt % of clay. This is attributed to the alignment/orientation of nanoclay platelets in the intercalated nanocomposite induced by capillary extrusion. In the nonlinear regime, the nanocomposites show increased shear viscosities when compared with the neat resin. The dependence of the shear viscosity on clay loading has analogous trend to that of G′ and G″. Finally, a comparison has been made between the complex and steady viscosities to verify the applicability of the empirical Cox‐Merz rule. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 542–549, 2006
Synthesis and characterization of superabsorbent hydrogels composites based on polysuccinimide
Authors: Yang Jun , Fang Li , Tan Tianwei
Published: July 2006

A kind of novel superabsorbent hydrogel with high swelling ratio property that could be used for the development of water absorbing resin, soil water retention agent, and chemical sand‐fixing material was synthesized in this study. The hydrogels were prepared by the crosslinking reaction of polysuccinimide (PSI). The relationships between swelling ratio and volume of solvent as well as the concentration of crosslinking agent were investigated in detail. Several composites, such as starch, carrageenan, and polyacrylamide, were added into hydrogels to enhance the swelling ratio. It was found that the swelling ratio was significantly increased, which the maximum water absorbency was enhanced 2.46 times when the composite polyacrylamide (PAM) was added compared to the control. The effects of ionic strength and sensitivity of pH on hydrogels were also studied. The modified hydrogels products with swelling ratio less sensitivity to the salinity as well as relative high swelling ration in salinity system were also obtained by adding PAM. Through the Fourier transform infrared spectroscopy (FTIR) characterizations, the crosslinking reaction mechanism and the structure of composite were proposed. In addition, the transmission electron microscopy (TEM) examinations showed that some composite materials elevated the physical crosslinked and connected channels density substantially. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 550–557, 2006
Vitrification, devitrification, and dielectric relaxations during the non‐isothermal curing of diepoxy‐cycloaliphatic diamine
Authors: Montserrat S. , Roman F. , Colomer P.
Published: July 2006

The curing of an epoxy resin based on diglycidyl ether of bisphenol A (DGEBA) with a diamine based on 4,4′‐diamino‐3,3′‐dimethyldicyclohexylmethane (3DCM) was analyzed by dielectric relaxation spectroscopy (DRS) between −100 and 220°C, at heating rates ranging from 0.1 to 2 K min−1. The permittivity, ε′, and the loss factor, ε″, were measured by DRS in the frequency range between 1 and 100 kHz. The dielectric relaxations were correlated with the relaxations observed previously by temperature modulated differential scanning calorimetry (TMDSC) at the same heating rates and in modulation conditions of amplitude 0.2 K and a period of 60 s, which is equivalent to a measuring frequency of 16.7 mHz. The dielectric measurements showed three frequency‐dependent dipolar relaxations and one ionic relaxation, which was independent of the frequency. The dipolar relaxations were associated with the glass transition of the unreacted system and the vitrification and the devitrification processes of the system during the crosslinking reaction, and the ionic relaxation was associated with the beginning of the crosslinking reaction. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 558–563, 2006
Synthesis of a side chain liquid crystalline polycarbonate with a chiral backbone
Authors: Sahin Y. Muge Calik , Serhatli I. Ersin , Menceloglu Yusuf Z.
Published: July 2006

We report the experimental demonstration of a novel and environmentally benign supercritical carbon dioxide (ScCO2) technique that yields an optically active, side chain liquid crystalline polycarbonate in a single‐step reaction. The obtained polymer is worthwhile, since it is highly stereoregular and can find applications in an enlarged mesomorphic temperature range compared to its acrylic analogues. The synthesized materials were characterized by IR, 1H‐NMR, and 13C‐NMR, while the thermal properties were measured by DSC. Polarized optical micrograph and wide angle X‐ray diffraction were used for the mesogenic property characterization of the copolymer. The transfer chirality from the backbone to the mesophase is demonstrated on the optical microscopy textures. Being consistent with the 13C‐NMR, X‐ray implies an ordered polymeric structure. The DSC analysis of the copolymer indicates that the Ti (the clearing point temperature) value does not change dramatically, whereas a pronounced decrease in Tg (the glass transition temperature) value is observed from that of its acrylic analogues. Hence, the obtained polymer exhibits another practical benefit by widening the mesomorphic temperature range. This study is the insightful combination of material processing and chemical design that elucidates the advantages of ScCO2 application, in terms of liquid crystallinity and the tacticity of the obtained polymer. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1915–1921, 2006
Contact angle determination on plasma‐treated poly(ethylene terephthalate) fabrics and foils
Authors: Hossain M. M. , Hegemann D. , Herrmann A. S. , Chabrecek P.
Published: July 2006

The surfaces of polyester (PET) fabrics and foils were modified by low‐pressure RF plasmas with air, CO2, water vapor as well as Ar/O2 and He/O2 mixtures. To increase the wettability of the fabrics, the plasma processing parameters were optimized by means of a suction test with water. It was found that low pressure (10–16 Pa) and medium power (10–16 W) yielded a good penetration of plasma species in the textile structure for all oxygen‐containing gases and gaseous mixtures used. While the wettability of the PET fabric was increased in all cases, the Ar/O2 plasma revealed the best hydrophilization effect with respect to water suction and aging. The hydrophilization of PET fabrics was closely related to the surface oxidation and was characterized by XPS analysis. Static and advancing contact angles were determined from the capillary rise with water. Both wetting and aging demonstrated a good comparability between plasma‐treated PET fabrics and foils, thus indicating a uniform treatment. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1452–1458, 2006
Polyacrylate‐core/TiO2‐shell nanocomposite particles prepared by in situ emulsion polymerization
Authors: Ai Zhaoquan , Sun Guilin , Zhou Qilong , Xie Changsheng
Published: July 2006

We report the preparation of polyacrylate‐core/TiO2‐shell nanocomposite particles through in situ emulsion polymerization in the presence of nano‐TiO2 colloid obtained by the hydrolysis of titanium tetrachloride. The resultant colloidal system can be stable for months without any precipitation. In a typical sample, the diameter of nanocomposite particles was about 150 nm, and the thickness of TiO2‐shell was 4–10 nm. Only cetyltrimethylammonium bromide was employed to provide the latex particles with positive charge, which was enough for the formation of fine TiO2 coatings. Three initiators were tested. Ammonia persulfate was the most suitable one, because the cooperative effect was formed by the negatively charged TiO2 particles and the terminal anionic group (SO42−, the fraction of Ammonia persulfate) of the polymer chain on the surface of latex particles to maintain the stability of nanocomposite system. The pH value played a vital role in obtaining a tight TiO2 coating. Transmission electron microscopy, X‐ray diffraction and Atomic force microscopy were used to characterize this nanocomposite material. It was found that rutile and anatase coexisted in the nanocomposite film. This may suggest a potential application in the field of photocatalytic coating. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1466–1470, 2006
Syntheses of poly(lactic acid)‐poly(ethylene glycol) serial biodegradable polymer materials via direct melt polycondensation and their characterization
Authors: Wang Zhao‐Yang , Zhao Yao‐Ming , Wang Fang
Published: July 2006

Directly starting from lactic acid (LA) and poly(ethylene glycol) (PEG), biodegradable material polylactic acid‐polyethylene glycol (PLEG) was synthesized via melt copolycondensation. The optimal synthetic conditions, including prepolymerization method, catalyst kinds and quantity, copolymerization temperature and time, LA stereochemical configuration, feed weight ratio mLA/mPEG and Mn of PEG, were all discussed in detail. When D,L‐LA and PEG (Mn = 1000 Da) prepolymerized together as feed weight ratio mD,l‐LA/mPEG = 90/10, 15 h copolycondensation under 165°C and 70 Pa, and 0.5 wt % SnO as catalyst, gave D,L‐PLEG1000 with the highest [η] of 0.40 dL/g, and the corresponding MW was 41,700 Da. Using L‐LA instead of D,L‐LA, 10 h polymerization under 165°C and 70 Pa, and 0.5 wt % SnO as catalyst, gave L‐PLEG1000 with the highest [η] of 0.21 dL/g and MW of 15,600 Da. Serial D,L‐PLEG with different feed weight ratio and Mn of PEG were synthesized via the simple and practical direct melt copolycondensation, and characterized with FTIR, 1H NMR, GPC, DSC, XRD, and contact angle testing. D,L‐PELG not only had higher MW than PDLLA, PLLA and L‐PELG, but also better hydrophilicity than PDLLA. The novel one‐step method could be an alternative route to the synthesis of hydrophilic drug delivery carrier PLEG instead of the traditional two‐step method using lactide as intermediate. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 577–587, 2006
Hot compaction of polyoxymethylene, part 1: Processing and mechanical evaluation
Authors: Jebawi K. Al , Sixou B. , Séguéla R. , Vigier G. , Chervin C.
Published: July 2006

The hot‐compaction of polyoxymethylene powders in the solid state, otherwise pressure‐assisted sintering, is studied as an alternative way to the melt‐compression or injection molding processes. A native powder issued from suspension polymerization has been used, together with powders obtained from grinding of melt‐extruded pellets. The experimental conditions were optimized with regard to temperature, pressure, and time. Temperature is the most sensitive parameter of the process. Sintering at temperature close to the onset of the melting range turned out to be necessary for an efficient welding of the powder particles, as judged from mechanical properties. Despite a strong loss of ductility, the sintered samples have been easily machined out into strips for mechanical testing. A significant increase in crystallinity is observed for the sintered samples, as compared with the compression‐molded ones, accompanied with a nearly twofold increase of the Young's modulus. Scanning electron microscopy revealed that rupture of the sintered samples involves both inter‐ and intra‐granular fracture. Welding of the crystallites via molecular diffusion at the particle interface is suggested to be the mechanism of sintering. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1274–1284, 2006
Relationship between anisotropic orientation and curing of liquid crystalline epoxy resin
Authors: Lee Jun Yeob
Published: July 2006

The effect of macroscopic orientation of liquid crystalline epoxy (LCE) resin, 4,4′‐di(2,3‐epoxypropenyloxy)phenyl benzoate, on the curing and liquid crystalline phase of LCE/diaminodiphenylester (DDE) mixture was investigated. Birefringence and curing rate of uniaxially aligned LCE/DDE on rubbed PI surface was compared with those of unaligned LCE/DDE. Anisotropic orientation accelerated the curing of LCE and facilitated the formation of liquid crystalline phase. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1712–1716, 2006
Filtration properties of electrospinning nanofibers
Authors: Qin Xiao‐Hong , Wang Shan‐Yuan
Published: July 2006

Electrospinning is a relatively simple method to produce submicron fibers from solutions of different polymers and polymer blends. The extensive application in future of electrospinning nanofibers is filtration. In this article, the filtration properties of electrospinning nanofibers were investigated. During the experiments, nanofibers layers with different area weight were electrospun on the spunbonded or meltblown sublayers. Fiber diameter, pore diameter, filtration efficiency as well as filtration resistance of nanofibers web and sublayers were measured, respectively, through a series of experiments. The results show that the fiber diameter of nanofibers is much smaller than that of sublayers. It is also found that the pore diameter of nanofibers web is much smaller than sublayers and coefficient variation of the pore diameter of nanofibers web is much smaller than sublayers. Moreover, the filtration efficiency and filtration resistance of sublayers are lower than nanofibers webs. The balance between efficiency and press drop is also investigated in the article. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1285–1290, 2006
Polyaniline salts and complexes: Efficient and reusable catalyst for the one‐pot synthesis of 5‐(methoxycarbonyl)‐6‐methyl‐4‐phenyl‐3,4‐dihydropyrimidin‐2(1h)‐one
Authors: Gangadasu Banda , Palaniappan Srinivasan , Amarnath Chellachamy Anbalagan , Rao Vaidya Jayathirtha
Published: July 2006

Polyaniline salts were prepared by doping polyaniline base with different Bronsted acids (sulfuric, nitric, phosphoric, perchloric, hydrochloric acid) and organic acids (p‐toluene sulfonic acid, 5‐sulfosalicylic acid). Polyaniline complexes were also prepared using Lewis acids (aluminum chloride, ferric chloride). Polyaniline salts and polyaniline complexes were used as catalysts in Biginelli reaction for 5‐(methoxycarbonyl)‐6‐methyl‐4‐phenyl‐3,4‐dihydropyrimidin‐2(1H)‐one synthesis. Benzaldehyde and urea were reacted with methyl acetoacetate using polyaniline‐p‐toluene sulfonate salt as catalyst with different reaction time, temperature, and amount of catalyst. The use of polyaniline catalysts is feasible because of the easy preparation, easy handling, stability, easy recovery, simple work‐up procedure, reusability, excellent activity with less amount of catalyst, and eco‐friendly nature. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1741–1745, 2006
Recycling of styrene polymers from shredded screen housings containing brominated flame retardants
Authors: Schlummer Martin , Mäurer Andreas
Published: July 2006

Recycling of plastics from screen housing poly mers is considered to be helpful to fulfill the requirements of the European waste of electric and electronic equipment directive. However, brominated flame retardants (BFR) and polybrominated dioxins and furans, which are partly limited in marketable products by European and German legislation, have been identified in waste screen housings and need to be eliminated. On application to housing shredder, sink and float was investigated as sorting technology, since BFR‐equipped styrene polymers exhibit higher densities compared to corres ponding non‐BFR types. The feasibility of this concept was proven by database studies and density monitoring of waste screen housing. Laboratory and small‐technical scale trials with different mixtures of TV‐sets and PC monitor housings revealed that only 5–20% of the original bromine load remained in the target fractions, resulting in bromine levels between 0.18–1.39%. Recycled polymers from fractions rich in HIPS‐based TV‐set casings did not exceed given threshold limits for PBDD/F and octabromodiphenylether. They were recovered with yields of 52–63% and exhibited mostly virgin‐like mechanical properties. In contrast, PC monitor housing fractions were characterized by low yield, high bromine levels in recycled products and brittle recycled polymers. Furthermore, pilot application of another separation approach, the specific swell and float technology, allowed the separation of upgraded HIPS qualities from bromine‐reduced TV‐set fractions. In contrast, this success has not yet been achieved with waste PC monitors. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1262–1273, 2006
Rheological properties of ethylcellulose latex
Authors: Gallardo V. , Morales M. E. , López‐Viota J. , Durán J. D. G. , Ruiz M. A.
Published: July 2006

Because of their large specific surface area, aqueous‐based pseudolatex systems of ethylcellulose can absorb large amounts of drugs. In addition, the stability of polymeric particles in biological fluids delays the release of the drug as in controlled drug delivery systems. The aim of the present study was to characterize the rheological properties of latex particles as a measure of their colloidal stability. Here, we report the effect of three variables: pH, electrolyte concentration, and temperature. The rheograms clearly show that the polymer suspensions displayed Bingham plastic behavior. Internal structuring of the latex was greatest at acid and natural pH values, particularly at the highest ionic strength. In acid solutions, only temperature appeared to play a fundamental role; both the shear stress corresponding to the onset of nonlinear viscoelasticity and the elastic modulus at all frequencies were higher at 37°C than those at room temperature. This is assumed to be a consequence of deformation of the polymer particles upon heating. The effect of ionic strength was noticeable only at the natural pH (pH ≅ 6.5). At high concentrations of sodium chloride, the particles aggregated because of the decrease in double layer repulsion, and as a result, the latex became structured and its elastic modulus subsequently increased. Interestingly, when the temperature was increased further, this structure presumably broke, down, at least partially, and the storage modulus was reduced. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 847–851, 2006
Mechanical properties and crosslink density of rare earth‐modified high‐abrasion furnace‐filled powdered natural rubber
Authors: Guo Yubo , Wang Lianshi , Zhang Anqiang
Published: July 2006

High‐abrasion furnace‐filled powdered natural rubber [P(NR/HAF)] has more advantages than traditional HAF‐filled bale NR (NR/HAF) because of its better environmental performance and easier processing quality, but its lower mechanical properties are disadvantageous. To improve the mechanical properties, rare earth‐modified HAF‐filled powdered NR [P(NR/HAF‐Ln)] (Ln = Sm,La,Pr) was prepared by means of coacervation–coprecipitation, using rare earth‐modified HAF as separant and filler. The effect on mechanical properties of P(NR/HAF‐Ln) vulcanizate exerted by the emulsifier/HAF ratio, powdering temperature, Ln/HAF ratio and type of Ln, and HAF content were studied. The results indicated that when optimum formulation, the mechanical properties of P(NR/HAF‐Ln) vulcanizate were better than P(NR/HAF) vulcanizate. In addition, the relationship of the apparent crosslink density and HAF content of P(NR/HAF‐Ln), P(NR/HAF), NR/HAF vulcanizates was also investigated, along with their SEM microphotographs of tensile fracture surface, which indicated that the excellent mechanical properties of P(NR/HAF‐Ln) vulcanizate was attributed to correct amount of Ln that could increase crosslink density and reinforce the interface structure of NR matrix/HAF‐Ln particle. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1755–1762, 2006
RAFT synthesis of poly(N‐isopropylacrylamide) and poly(methacrylic acid) homopolymers and block copolymers: Kinetics and characterization
Authors: Yang Chiming , Cheng Yu‐Ling
Published: July 2006

Reversible addition‐fragmentation chain transfer (RAFT) polymerization was used successfully to synthesize temperature‐responsive poly(N‐isopropylacrylamide) (PNIPAAm), poly(methacrylic acid) (PMAA), and their temperature‐responsive block copolymers. Detailed RAFT polymerization kinetics of the homopolymers was studied. PNIPAAm and PMAA homopolymerization showed living characteristics that include a linear relationship between Mn and conversion, controlled molecular weights, and relatively narrow molecular weight distribution (PDI < 1.3). Furthermore, the homopolymers can be reactivated to produce block copolymers. The RAFT agent, carboxymethyl dithiobenzoate (CMDB), proved to control molecular weight and PDI. As the RAFT agent concentration increases, molecular weight and PDI decreased. However, CMDB showed evidence of having a relatively low chain transfer constant as well as degradation during polymerization. Solution of the block copolymers in phosphate buffered saline displayed temperature reversible characteristics at a lower critical solution temperature (LCST) transition of 31°C. A 5 wt % solution of the block copolymers form thermoreversible gels by a self‐assembly mechanism above the LCST. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1191–1201, 2006
Preparation of polyamide resin‐encapsulated melamine cyanurate/melamine phosphate composite flame retardants and the fire‐resistance to glass fiber‐reinforced polyamide 6
Authors: Liu Yuan , Wang Qi , Fei Guoxia , Chen Yinghong
Published: July 2006

In this study, melamine cyanurate (MCA)/melamine phosphate (MP) composite flame retardants were synthesized in the solution of phosphoric acid/polyamide 6 (PA6). Phosphoric acid acted as the solvent of PA6, catalyst of melamine‐cyanurate self‐assembly reaction and reactant of melamine‐phosphoric acid reaction. With the consumption of the acid, the pH value of the system increased, and the solved PA6 precipitated on the surface of the flame retardant particles to form polymeric encapsulation. This technology realized the synthesis and surface modification of the flame retardants in one process. The catalyst and solvent, phosphoric acid, was finally converted into the product MP, and need no an additional removing process. The encapsulated MCA/MP (EMCMP) composite flame retardants were successfully applied in the fire‐resistance to glass fiber (GF)‐reinforced PA6. Because the encapsulated layer of EMCMP was also PA6, good interfacial compatibility and effective dispersion of EMCMP in PA6 resin can be obtained, and the corresponding flame retardant materials showed excellent flame retardancy and mechanical performance. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1773–1779, 2006
Durable antibacterial finish on cotton fabric by using chitosan‐based polymeric core‐shell particles
Authors: Ye Weijun , Xin John H. , Li Pei , Lee Kam‐Len Daniel , Kwong Tsz‐Leung
Published: July 2006

Cotton fabric with excellent antibacterial durability was obtained when treated with chitosan‐containing core‐shell particles without any chemical binders. These amphiphilic nanosized particles with antibacterial chitosan shells covalently grafted onto polymer cores were prepared via a surfactant‐free emulsion copolymerization in aqueous chitosan. Herein, two core‐shell particles, one with poly(n‐butyl acrylate) soft core and another with crosslinked poly(N‐isopropylamide) hard core, were synthesized and applied to cotton fabric by a conventional pad‐dry‐cure process. Antimicrobial activity was evaluated quantitatively using a Shake Flask Method in which the reduction of the number of Staphylococcus aureus cells was counted. The results showed that treated fabric had an excellent antibacterial property with bacterial reduction higher than 99%. The antibacterial activity maintained at over 90% reduction level even after 50 times of home laundering. The fabric surface morphology as well as the effect of latex particles with different core flexibilities on fabric hand, air permeability, break tensile strength, and elongation was investigated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1787–1793, 2006
A cellulose‐based hydrogel as a potential bulking agent for hypocaloric diets: An in vitro biocompatibility study on rat intestine
Authors: Sannino A. , Madaghiele M. , Lionetto M. G. , Schettino T. , Maffezzoli A.
Published: July 2006

A number of over‐the‐counter slimming products are currently available on the market. However, there is no scientific consensus over their effectiveness in promoting and sustaining weight loss. The need to develop an alternative dietary supplement for the treatment of obesity and overweight makes attractive a polyelectrolyte cellulose‐based hydrogel, crosslinked through a water soluble carbodiimide, as a potential bulking agent or stomach filler for hypocaloric diets. The hydrogel is envisaged to be administered orally to absorb water in the stomach, thus swelling and giving a sense of fullness, and to be finally expelled by fecal way. To this purpose, a preliminary assessment of hydrogel swelling capacity in distilled water has been performed, and the biocompatibility of the material with respect to intestinal tissues has been evaluated in vitro. The direct contact with the intestinal mucosa in vivo has been simulated by contacting the hydrogel with the jejunum tract of rat intestine, and the capacity of the material to maintain the epithelial barrier integrity has been monitored by means of transepithelial electric resistance measurements and lactate dehydrogenase release assay. The reported results evidence that the hydrogel is well tolerated by the intestinal tissue during the expected time of contact in vivo. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1524–1530, 2006
Application of degradation kinetics to the rheology of poly(hydroxyalkanoates)
Authors: Harrison Graham M. , Melik David H.
Published: July 2006

The time‐dependent rheological behavior of a series of 3‐hydroxybuytrate‐based semicrystalline copolymers is employed to determine the expected rheological curves that would be generated in the absence of any polymer degradation. Both dynamic frequency sweep and shear rate sweep experiments were analyzed. A model for the degradation kinetics, coupled with standard rheological relationships, was employed to extrapolate the measured sweeps to predicted curves at time zero, prior to degradation. The model is broadly applicable over a wide range of frequencies or shear rates, and generates a single degradation rate constant k for each polymer studied. A similar, although ad hoc, procedure was applied to the dynamic storage and loss moduli. The model provides a method for determining the rheological behavior of degrading polymers over a time interval, typically found in processing applications. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:1794–1802, 2006
Preparation, characterization, and thermal properties of polystyrene‐block‐quaternized poly(4‐vinylpyridine)/Montmorillonite nanocomposites
Authors: Zhang Bao‐Qing , Chen Guang‐De , Pan Cai‐Yuan , Luan Bin , Hong Chun‐Yan
Published: July 2006

Polystyrene‐block‐poly(4‐vinylpyridine) (PS‐b‐P4VP) was synthesized by two steps of reversible addition‐fragmentation transfer (RAFT) polymerization of styrene (St) and 4‐vinylpyridine (4VP) successively. After P4VP block was quaternized with CH3I, PS‐b‐quaternized P4VP/montmorillonite (PS‐b‐QP4VP/MMT) nanocomposites were prepared by cationic exchange reactions of quaternary ammonium ion in the PS‐b‐QP4VP with ions in MMT. The results obtained from X‐ray diffraction (XRD) and transmission electron microscopy (TEM) images demonstrate that the block copolymer/MMT nanocomposites are of intercalated and exfoliated structures, and also a small amount of silicates' layers remained in the original structure; differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) results show that the nanocomposites displayed higher glass transition temperature (Tg) and higher thermal stability than that of the corresponding copolymers. The blending of PS‐b‐QP4VP/MMT with commercial PS makes MMT to be further separated, and the MMT was homogeneously dispersed in the polymer matrix. The enhancement of thermal stability of PS/PS‐b‐QP4VP/MMT is about 20°C in comparison with commercial PS. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:1950–1958, 2006
Preparation and crystallization of poly(ethylene terephthalate)/SiO2 nanocomposites by in‐situ polymerization
Authors: Yang Yongzhe , Xu Hong , Gu Hongchen
Published: July 2006

Poly(ethylene terephthalate) (PET)/SiO2 nanocomposites were prepared by in situ polymerization. The dispersion and crystallization behaviors of PET/SiO2 nanocomposites were characterized by means of transmission electron microscope (TEM), differential scanning calorimeter (DSC), and polarizing light microscope (PLM). TEM measurements show that SiO2 nanoparticles were well dispersed in the PET matrix at a size of 10–20 nm. The results of DSC and PLM, such as melt‐crystalline temperature, half‐time of crystallization and crystallization kinetic constant, suggest that SiO2 nanoparticles exhibited strong nucleating effects. It was found that SiO2 nanoparticles could effectively promote the nucleation and crystallization of PET, which may be due to reducing the specific surface free energy for nuclei formation during crystallization and consequently increase the crystallization rate. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 655–662, 2006
Novel Template‐Directed Anodic Phenol‐Coupling Reaction
Authors: Malkowsky Itamar M. , Rommel Christina E. , Fröhlich Roland , Griesbach Ulrich , Pütter Hermann , Waldvogel Siegfried R.
Published: July 2006

Substituted phenols were anodically coupled to the corresponding 2,2′‐biphenols via tetraphenoxy borate derivatives. This electrochemical method is particularly useful for methyl‐substituted substrates, such as 2,4‐dimethyl phenol. The selective ortho‐coupling reaction can be easily performed on a multikilogram scale.
Copper(II)‐Promoted Regioselective Synthesis of 1,4‐Disubstituted 1,2,3‐Triazoles in Water.
Authors: Reddy K. Rajender , Rajgopal K. , Kantam M. Lakshmi
Published: July 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Four New Isoflavonoids from the Stem Bark of Erythrina variegata.
Authors: Li Xiaoli , Wang Naili , Wong Man Sau , Chen Albert S. C. , Yao Xinsheng
Published: July 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Cancer incidence after localized therapy for prostate cancer
Authors: Moon Kihyuck , Stukenborg George J. , Keim Jessica , Theodorescu Dan
Published: July 2006

BACKGROUND.

Second cancers may occur in patients who have undergone radiation therapy. The risk for these adverse events after therapy is uncertain. In this study, the authors examined the size and significance of the observed association between occurrences of secondary cancers 5 years after radiotherapy in a large population of men with incident prostate cancer.

METHODS.

Men with incident prostate cancer were identified from the Surveillance, Epidemiology, and End Results (SEER) registry and were distinguished by the type of treatment received, tumor stage, tumor grade, and age at diagnosis. SEER data also were used to identify occurrences of secondary cancer beginning 5 years after the date patients were diagnosed with prostate cancer. Multivariate logistic regression analysis was used to estimate the adjusted odds of the subsequent occurrence of other cancers associated with types of radiation therapy received and was adjusted for the type of surgery, tumor grade, stage, and patient age.

RESULTS.

Compared with men who received no prostate cancer‐directed radiation, men who received external beam radiation therapy (EBRT) as their only form of radiation therapy had statistically significant increased odds of developing secondary cancers at several sites potentially related to radiation therapy, including the bladder (odds ratio [OR], 1.63; 95% confidence interval [95% CI], 1.44–1.84) and rectum (OR, 1.60; 95% CI, 1.29–1.99). Men who received EBRT also had statistically significant higher odds of developing secondary cancers at sites in the upper body and other areas not potentially related to radiation therapy, including the cecum (OR, 1.63; 95% CI, 1.10–1.70), transverse colon (OR, 1.85; 95% CI, 1.30–2.63), brain (OR, 1.83; 95% CI, 1.22–2.75), stomach (OR, 1.38; 95% CI, 1.09–1.75), melanoma (OR, 1.29; 95% CI, 1.09–1.53), and lung and bronchus (OR, 1.25; 95% CI, 1.13–1.37) compared with the odds among men who received no radiation therapy. Men who received radiation therapy in the form of radioactive implants or isotopes, either in isolation or combined with beam radiation, did not have significantly different odds of secondary cancer occurring at any of the 20 most common sites.

CONCLUSIONS.

Patients who received with EBRT had significantly higher odds of developing second cancers both overall and in the areas that were exposed to radiation. It is noteworthy that, to the authors' knowledge, this report shows for the first time that, despite the higher doses of radiation delivered, patients who received radioactive implants had the lowest odds of developing second cancers. Cancer 2006. © 2006 American Cancer Society.
A phase I/II study of weekly high‐dose erlotinib in previously treated patients with nonsmall cell lung cancer
Authors: Milton Daniel T. , Azzoli Christopher G. , Heelan Robert T. , Venkatraman Ennapadam , Gomez Jorge E. , Kris Mark G. , Krug Lee M. , Pao William , Rizvi Naiyer A. , Dunne Megan , Miller Vincent A.
Published: July 2006

BACKGROUND.

Preclinical studies have suggested that erlotinib at high doses may inhibit additional sites downstream of the epidermal growth factor receptor (EGFR), resulting in greater antitumor efficacy. The objective of this study was to determine the tolerability and efficacy of high‐dose erlotinib administered on a weekly schedule to patients with advanced nonsmall cell lung cancer (NSCLC).

METHODS.

The authors conducted a Phase I/II trial of weekly erlotinib in patients with progressive NSCLC who had received previous chemotherapy. In the Phase I portion, patients were enrolled in 3‐patient cohorts at erlotinib dose levels of 1200 mg, 1600 mg, and 2000 mg once weekly. The Phase II portion was designed to determine the major objective response rate of the dose identified in the Phase I portion of the trial.

RESULTS.

Twenty‐seven patients were enrolled. No dose‐limiting toxicity was observed. Grade 1 and 2 rash and diarrhea were the principle toxicities, and each occurred in 92% of patients. Among 21 patients who were treated at the Phase II dose of 2000 mg weekly, a single objective response was identified, yielding a response rate of 5% (95% confidence interval, 0.2–22%). For this cohort, the median survival was 9.5 months. The sole radiographic response occurred in a patient whose pretreatment tumor specimen harbored an EGFR exon 19 deletion.

CONCLUSIONS.

Erlotinib at a dose of 2000 mg administered weekly was tolerated well by these patients with advanced NSCLC. The 5% objective response rate did not reach the stated objective at the interim efficacy analysis, prompting the closure of the study. Cancer 2006. © 2006 American Cancer Society.
Phase II trial of weekly paclitaxel and gemcitabine for previously untreated, stage IIIB‐IV nonsmall cell lung cancer
Authors: Akerley Wallace , Safran Howard , Zaner Ken , Ready Neal , Mega Tony , Kennedy Teresa
Published: July 2006

BACKGROUND.

The purpose of the current study was to evaluate the efficacy and tolerance of the noncisplatin‐based combination of paclitaxel and gemcitabine administered weekly for patients with untreated metastatic nonsmall cell lung cancer (NSCLC).

METHODS.

Patients with Stage IIIB/IV or recurrent NSCLC, a performance status of 0–2, and no prior chemotherapy exposure were eligible. Patients received gemcitabine 1000 mg/m2 and paclitaxel 85 mg/m2 on Days 1, 8, 15, 22, 29, 36 of an 8‐week cycle until progression.

RESULTS.

Thirty‐nine eligible patients were enrolled. The median age was 66 years and 14 patients were ≥70 years old. Performance status was 2 in 13 (33%) and 29 patients (75%) had Stage IV. Five patients (12.8%) developed interstitial pneumonitis and 2 of these were responsive to steroid therapy. The overall response rate was 23.1%, with no complete responses. The median survival was 32 weeks and the 1‐year survival was 32%.

CONCLUSIONS.

This regimen of weekly paclitaxel and gemcitabine has modest activity in advanced NSCLC. Cancer 2006. © 2006 American Cancer Society.
Enhanced Electron Transfer Rate in a Rigid Ferrocene–Fulleropyrrolidine Dyad
Authors: Caporossi Francesco , Floris Barbara , Galloni Pierluca , Gatto Emanuela , Venanzi Mariano
Published: July 2006

A rigid ferrocene–fullerene dyad was obtained from fullerene (C60), N‐methylglycine and 1,1′‐(α‐oxotrimethylene)ferrocene. The frozen geometry resulted in an enhanced electron transfer rate from ferrocene to fullerene moieties, when compared with conformationally flexible N‐methyl‐2‐ferrocenylfulleropyrrolidine. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Does exhaustive exercise result in oxidative stress and associated DNA damage in the chub (Leuciscus cephalus)?
Authors: Aniagu Stanley O. , Day Norman , Chipman J. Kevin , Taylor Edwin W. , Butler Patrick J. , Winter Matthew J.
Published: July 2006

DNA strand breaks [as determined by the conventional and formamidopyrimidine glycosylase (FPG)‐modified Comet assay] and antioxidant defense status [as indicated by superoxide dismutase (SOD) activity and reduced glutathione (GSH) concentration] were evaluated in healthy adult chub (Leuciscus cephalus) after exhaustive exercise [swimming to their critical swimming speed (Ucrit), twice in succession with a 40 min rest period between] vs. confined (unexercised) control fish. The conventional Comet assay revealed significantly higher DNA strand breaks in all the tissues (blood, liver, and gill), with the highest increase over background evident in the epithelial gill cells of swum fish compared to the controls. Moreover, when the FPG‐modified Comet assay was conducted to reveal specific oxidative lesions, the gill cells of exercised fish sustained the highest level of oxidative DNA damage in comparison to the control. Data on tissue antioxidant defense mechanism were less conclusive, with no significant differences in the tissue levels of SOD or GSH. This suggests that either the degree of oxidative stress was not great enough to evoke a response in terms of defense mechanisms or the timescale of antioxidant defense response was somewhat different from the time between the application of stress and subsequent tissue sampling. From the swimming data, Ucrit was significantly lower on the second assessment compared to the first (repeat ratio: 0.76), suggesting that the fish were exercised to a level which was not sustainable. Overall, these findings support the theory that acute extreme exercise could result in oxidative stress and associated DNA damage in fish. These observations suggest that fish living in fast flowing and polluted rivers are at increased risk of DNA damage. Environ. Mol. Mutagen., 2006. © 2006 Wiley‐Liss, Inc.
Distribution of microstructural damage in the brains of professional boxers: A diffusion MRI study
Authors: Chappell Michael H. , Uluǧ Aziz M. , Zhang Lijuan , Heitger Marcus H. , Jordan Barry D. , Zimmerman Robert D. , Watts Richard
Published: July 2006

Purpose

To investigate and localize cerebral abnormalities in professional boxers with no history of moderate or severe head trauma.

Materials and Methods

Diffusion tensor imaging (DTI) was used to determine the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) in the brains of 81 professional male boxers and 12 male control subjects. Voxel‐based analysis (VBA) of both the diffusion and anisotropy values was performed using statistical parametric mapping (SPM). From this objective analysis, regions of microstructural abnormalities in the brains of the boxers were located.

Results

Increases in the ADC, and decreases in FA were identified in deep white matter (WM), while decreases in ADC were identified in cortical gray matter (GM). Regions of positive correlation between ADC and age were also found in both the boxer and control groups, although the regions and strength of the correlation were not the same in each group.

Conclusion

Using VBA, we localized previously unreported abnormalities in the brains of professional boxers. These abnormalities are assumed to reflect cumulative (chronic) brain injury resulting from nonsevere head trauma. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Characterization of cortical thickness and ventricular width in normal aging: A morphometric study at 3 Tesla
Authors: Preul Christoph , Hund‐Georgiadis Margret , Forstmann Birte U. , Lohmann Gabriele
Published: July 2006

Purpose

To describe loss of cortical thickness and ventricular enlargement during normal aging in a sample of 525 neurologically and psychiatrically inconspicuous subjects (17–68 years old).

Materials and Methods

An automated segmentation algorithm was applied to assess cortical thickness and compared with conventional measurements of ventricular indices (ventricular body index (VBI), anterior horn index (AHI), and third ventricular width) as performed in clinical practice. Regression analysis was performed to elucidate the relationship between a decrease of the cortical mantle and increase in ventricular width with aging.

Results

Cortical thickness decreases with age (r = –0.49, P < 0.01; r = –0.502 in male and r = –0.461 in female subjects). Regarding the ventricular indices, we found a significant correlation with age for both the whole sample and the subdivision by gender. Cortical thickness and ventricular width are closely correlated (r = –0.43 in women, r = –0.468 in men, P < 0.001 each). The bandwidth of variance scales up with aging in all parameters. The results are discussed in terms of the underlying mechanisms of normal aging.

Conclusion

Our findings suggest that a decrease in cortical thickness and increase in ventricular width occur with normal aging. The enlargement of the third ventricle correlates the most strongly with age. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Function of ID1 protein in human cord blood‐derived neural stem‐like cells
Authors: Jurga M. , Buzañska L. , Małecki M. , Habich A. , Domañska‐Janik K.
Published: July 2006

The effect of dominant‐negative regulator of basic helix‐loop‐helix (bHLH) transcription factors, an ID1 protein, on growth and differentiation of neural stem‐like cell line derived from human umbilical cord blood (HUCB‐NSC) was investigated. This nontransformed, mesodermal germ layer‐originated line contains high levels of ID1 protein, whose intercellular distribution reflects HUCB‐NSC differentiation status. Whereas cells remained undifferentiated and self‐renewing in serum‐free (SF) cultures, ID1 protein, although highly expressed, did not attain cell nuclei and was localized mainly in cytoplasm. In long‐term‐expanded cultures of partially committed (primed) HUCB‐NSC grown in a low serum concentration (LS cultures) ID1 protein became translocated toward cell nuclei. Further neuronal differentiation of the cells, either spontaneous in the presence of serum or induced by neuromorphogens (dBcAMP, RA), resulted in almost complete depletion ofID1mRNA and protein. Accordingly, HUCB‐NSC transfectants overexpressing the ID1 gene were significantly inhibited in their differentiation. Notably, only neuronal and not glial development was affected after ID1 overexpression. A similar gain‐of‐function effect of ID1 transfection was observed in human NSC‐like line (DEV) of medullobastoma origin, which is constitutively devoid of ID1 expression. Thus, our results on HUCB‐NSC confirm further its neural‐specific behavior and the crucial role of ID1 protein as a potent negative regulator of neural stem cell differentiation, pointing out that this protein distribution between cytoplasmic and nuclear cell compartments can be one of the most important steps in differentiation signal transduction. © 2006 Wiley‐Liss, Inc.
How advertising claims affect brand preferences and category–brand associations: The role of regulatory fit
Authors: Florack Arnd , Scarabis Martin
Published: July 2006

Two experiments examined whether selfregulatory goals addressed in advertising claims influence product preferences and category– brand associations. Experiment 1 provided evidence for the hypothesis that the fit between an advertising claim and consumers' regulatory focus has an impact on product preferences. Participants were more likely to prefer products presented in an advertisement with a claim compatible with the experimentally induced focus. Experiment 2 demonstrated that regulatory focus also has an impact on category– brand associations. Category–brand associations were stronger when the claim of a target brand was compatible with the regulatory focus at the time category–brand associations were measured. © 2006 Wiley Periodicals, Inc.
Context‐induced and ad‐induced affect: Individual differences as moderators
Authors: Chang Chingching
Published: July 2006

The present article had two objectives: (a) to explore the relative impacts of context‐induced and ad‐induced affect on ad and brand evaluations, and (b) to investigate how individual differences in affect intensity and introversion/extroversion moderate the effects of ad‐induced affect. In Study 1, ad‐induced affect, but not contextinduced affect, significantly influenced ad and brand evaluations when both forms of affect induction were manipulated. Furthermore, Studies 1 and 2 showed that individuals scoring differently on affect intensity and introversion/extroversion responded in divergent ways to ad messages that elicited positive and negative affect. © 2006 Wiley Periodicals, Inc.