bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of the filler loading and aging time on the mechanical and electrical conductivity properties of carbon black filled natural rubber
Authors: Azura A. R. , Ghazali Suriati , Mariatti M.
Published: July 2008

The effects of the filler loading and aging time on the mechanical and electrical conductivity properties of natural rubber were investigated. In this work, carbon black (type N220) was used as a filler, and its loading was varied from 0 to 50 phr. The mechanical properties (e.g., the tensile strength and catastrophic tearing energy) increased with a filler loading up to a certain loading, and a decrease in the mechanical properties was observed with higher filler loadings. The tensile strength and catastrophic tearing energy of the aged samples decreased after 3 and 6 days of aging at 100°C. The results for the electrical conductivity properties of unaged samples showed a percolation threshold at 20 phr, and the values were consistent with further filler loadings. After aging, the percolation threshold was still maintained at 20 phr. The morphologies of unaged and aged samples were significantly different: holes were observed to occur in the aged samples. This might have been due to the movement of fillers when the materials were subjected to heat, and this subsequently influenced the mechanical properties of the natural rubber composites. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Degradation behavior of an ultraviolet and hygrothermally aged polyurethane elastomer: Fourier transform infrared and differential scanning calorimetry studies
Authors: Ludwick Adriane , Aglan Heshmat , Abdalla Mohamed O. , Calhoun Maria
Published: July 2008

The degradation behavior of an elastomeric polyurethane (PU) was investigated with accelerated ultraviolet (UV) and hygrothermal (HT) techniques. Samples were subjected to UV exposure and HT conditions for 3 or 5 months and were removed in 1‐month intervals from the test chambers. Their chemical structure was evaluated with Fourier transform infrared (FTIR) spectroscopy. The thermal transitions of the aged samples were evaluated with differential scanning calorimetry (DSC). Both FTIR and DSC results showed no evidence of significant structural damage to the HT‐aged PU throughout exposure. FTIR analysis of the UV‐aged samples showed a noticeable change in the chemical structure of the polymer after 1 month of UV exposure. The results from DSC correlated with the FTIR analysis of the UV‐aged samples. Spectroscopic and thermal analysis of the aging of the PU samples was correlated to mechanical analysis. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis and properties of poly[N‐(4‐n‐butoxybenzoyl)‐2‐ethynylpyridinium chloride]
Authors: Gal Yeong‐Soon , Jin Sung‐Ho , Park Jong‐Wook
Published: July 2008

We first synthesized a new ionic polyacetylene with benzoyl functional groups by the activation polymerization of 2‐ethynylpyridine with 4‐butoxybenzoyl chloride without any additional initiator or catalyst. The acetylenic triple bond of N‐benzoyl‐2‐ethynylpyridinium chloride, formed in the first quaternarization process, was also found to be susceptible to linear polymerization. The polymer structure was characterized by various instrumental methods to give the ideal conjugated polyene backbone structure with the designed N‐(4‐n‐butoxybenzoyl‐2‐ethynylpyridinium) substituent and chloride counterion. The photoluminescence spectrum showed two distinguished maximum values at 575 and 630 nm, corresponding to photon energies of 2.16 and 1.97 eV, respectively. The electrochemical properties of this ionic polyacetylene were also measured and are discussed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis and characterization of novel, biodegradable, thermally stable chitin‐based polyurethane elastomers
Authors: Zia Khalid Mahmood , Barikani Mehdi , Bhatti Ijaz Ahmad , Zuber Mohammad , Bhatti Haq Nawaz
Published: July 2008

Biodegradable polyurethane (PU) elastomers with potential for biomedical and industrial applications with tunable thermal properties were synthesized by the reaction of poly(ϵ‐caprolactone) and 4,4′‐diphenylmethane diisocyanate and extended with different mass ratios of chitin and 1,4‐butane diol (BDO). Their chemical structures were characterized with Fourier transform infrared, 1H‐NMR, and 13C‐NMR spectroscopy, and the thermal properties were determined by thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical thermal analysis techniques. The incorporation of chitin contents into the PU backbone caused improvements in the thermal stability and degradation rate. Optimum thermal properties and degradation profile were obtained from elastomers extended with chitin, whereas elastomers extended with BDO displayed the worst properties. The investigation of the structure–property relationships of the prepared elastomers showed that the main determining factors for the observed properties were the physical effective crosslink density, hydrogen bonding, thermal stability, and content of chitin in the PU backbone. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Properties and application of poly(methacrylic acid‐co‐dodecyl methacrylate‐cl‐N,N‐methylene bisacrylamide) hydrogel immobilized Bacillus cereus MTCC 8372 lipase for the synthesis of geranyl acetate
Authors: Verma Madan Lal , Kanwar Shamsher Singh
Published: July 2008

A range of fatty acid esters is now being produced commercially with immobilized microbial lipases (glycerol ester hydrolases; EC) in nonaqueous solvents. In this study, a synthetic hydrogel was prepared by the copolymerization of methacrylic acid and dodecyl methacrylate in the presence of a crosslinker, N,N‐methylene bisacrylamide. A purified alkaline thermotolerant bacterial lipase from Bacillus cereus MTCC 8372 was immobilized on a poly(methacrylic acid‐co‐dodecyl methacrylate‐cl‐N,N‐methylene bisacrylamide) hydrogel by an adsorption method. The hydrogel showed a 95% binding efficiency for the lipase. The bound lipase was evaluated for its hydrolytic potential toward various p‐nitrophenyl acyl esters with various C chain lengths. The bound lipase showed optimal hydrolytic activity toward p‐nitrophenyl palmitate at a pH of 8.5 and a temperature of 55°C. The hydrolytic activity of the hydrogel‐bound lipase was enhanced by Hg2+, Fe3+, and NH ions at a concentration of 1 mM. The hydrogel‐bound lipase was used to synthesize geranyl acetate from geraniol and acetic acid in n‐heptane. The optimization of the reaction conditions, such as catalyst loading, effect of substrate concentration, solvent (n‐pentane, n‐hexane, n‐heptane, n‐octane, and n‐nonane), reaction time, temperature, molecular sieve (3 Å × 1.5 mm) and scale up (at 50‐mL level), was studied. The immobilized lipase (25 mg/mL) was used to perform an esterification in n‐alkane(s) that resulted in the synthesis of approximately 82.8 mM geranyl acetate at 55°C in n‐heptane under continuous shaking (160 rpm) after 15 h when geraniol and acetic acid were used in a ratio of 100 : 100 mM. The addition of a molecular sieve (3 Å × 1.5 mm) to the reaction system at a concentration of 40 mg/mL in reaction volume (2 mL) resulted in an increase in the conversion of reactants into geranyl acetate (90.0 mM). During the repetitive esterification under optimum conditions, the hydrogel‐bound lipase produced ester (37.0 mM) after the eighth cycle of reuse. When the reaction volume was scaled up to 50 mL, the ester synthesized was 58.7 mM under optimized conditions. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Optimized conditions for the grafting reaction of poly(methyl methacrylate) onto oil‐palm empty fruit bunch fibers
Authors: Bakar Aznizam Abu , Mat Nik Sulaiman Nik , Isnin Mohd Kamaruddin
Published: July 2008

This article describes the graft copolymerization of poly(methyl methacrylate) (PMMA) onto oil‐palm empty fruit bunches (OPEFBs) with a fiber length of less than 75 μm. The graft copolymerization was carried out under a nitrogen atmosphere by a free‐radical initiation technique in an aqueous medium. Hydrogen peroxide and ferrous ions were used as a redox initiator/cocatalyst system. The PMMA homopolymer that formed during the reaction was removed from the grafted copolymers by Soxhlet extraction. Determining the effects of the reaction period, reaction temperature, and monomer concentration on the grafting percentage was the main objective, and they were investigated systematically. The optimum reaction period, reaction temperature, monomer concentration, and initiator concentration were 60 min, 50°C, 47.15 × 10−3 mol, and 3.92 × 10−3 mol, respectively. The maximum percentage of grafting achieved under these optimum conditions was 173%. The presence of PMMA functional groups on OPEFB and the enormous reduction of the hydroxyl‐group absorption band in PMMA‐g‐OPEFB spectra provided evidence of the successful grafting reaction. The improvement of the thermal stability of PMMA‐g‐OPEFB also showed the optimal achievement of the grafting reaction of PMMA onto OPEFB. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Fracture behavior of thermoplastic polyolefin/clay nanocomposites
Authors: Tjong S. C. , Ruan Y. H.
Published: July 2008

A thermoplastic polyolefin (TPO) containing 70 wt % styrene–ethylene–butadiene‐styrene‐g‐maleic anhydride and 30 wt % polypropylene and its nanocomposites reinforced with 0.3–1.5 wt % organoclay were prepared by melt mixing followed by injection molding. The mechanical and fracture behaviors of the TPO/clay nanocomposites were investigated. The essential work of fracture (EWF) approach was used to evaluate the tensile fracture behavior of the nanocomposites toughened with elastomer. Tensile tests showed that the stiffness and tensile strength of TPO was enhanced by the addition of low loading levels of organically modified montmorillonite. EWF measurements revealed that the fracture toughness of the TPO/clay nanocomposites increased with increasing clay content. The organoclay toughened the TPO matrix of the nanocomposites effectively. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Preparation and self‐assembly behavior of thermosensitive polymeric micelles comprising poly(styrene‐b‐N,N‐diethylacrylamide)
Authors: Bian Fengling , Xiang Miao , Yu Wei , Liu Mingzhu
Published: July 2008

The amphiphilic block copolymer poly(styrene‐b‐N,N‐diethylacrylamide) (PSt‐b‐PDEA) was synthesized by reversible addition‐fragmentation chain transfer (RAFT) polymerization of styrene and N,N‐diethylacrylamide. The results of 1H‐NMR and GPC analysis showed that the synthesized PSt‐b‐PDEA copolymer had controlled molecular weight and narrow polydispersity. Polymeric micelles having a unimodal size distribution with an average diameter of 40 ± 0.5 nm were obtained from purified PSt‐b‐PDEA using a dialysis method. And the results showed that the clearance of homopolymer in copolymer is the key to prepare the unimodal distribution core‐shell nanomicelles. The micelles were thermodynamically stable in aqueous media with a low critical micelle concentration value (0.1 mg L−1). The aqueous micelles solution underwent a reversible dispersion/aggregation transition at around 29°C, which corresponds to the lower critical solution temperature (LCST) of the outer shell PDEA block chains. It is hoped that with their unique characteristics, those thermoresponsive polymeric micelles would found application in drug delivery. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Effect of branched PP content on the physical properties and cell growth during foaming of TPOs
Authors: McCallum Tara J. , Kontopoulou Marianna , Park Chul B. , Wong Anson , Kim Seong G.
Published: July 2008

Linear/branched PP blends at various ratios were used as the matrix for thermoplastic olefin (TPO) compounds, containing an ethylene–octene copolymer dispersed phase. A detailed investigation of the physical properties of these blends revealed that addition of branched PP (BPP) resulted in improved stiffness and flexural properties. Given that the phase morphology of the blends and the interfacial tension between their components remained virtually unaffected, these improvements are attributed to the higher stiffness of the BPP‐containing matrices. Talc‐filled TPOs containing branched PPs exhibited further improvements in the stiffness and flexural properties. An investigation into the bubble growth process during foaming using a batch foaming simulation system revealed that the presence of BPP resulted in a slight delay in cell nucleation, whereas the rate of bubble growth was not significantly altered. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Influence of treatment duration on hydrophobic recovery of plasma‐treated ultrahigh modulus polyethylene fiber surfaces
Authors: Ren Yu , Hong Yuyan , Sun Jie , Qiu Yiping
Published: July 2008

One of the major disadvantages of ultrahigh modulus polyethylene (UHMPE) fibers is their low surface energy which makes them difficult to adhere to most of the resins used in composites. Therefore, UHMPE fibers are often treated with plasmas to improve their surface properties. However, aging of plasma treatment effect is a major concern for plasma‐treated fibers. In this study, UHMPE fibers were treated for 30, 60, 90, and 120 s with Ar/O2 plasma on a dielectric barrier discharge device. The change of the surface properties and adhesion characteristics of the fibers were investigated immediately after and 30 days after the plasma treatments using X‐ray photoelectron spectroscopy, contact angle measurement, scanning electron microscopy, and micro‐bond tests. Results show that aging of the plasma treatment effect was suppressed by increasing the plasma treatment duration. The interfacial shear strengths were increased from 4 MPa to 5.9, 7.8, 9.2, and 7.6 MPa for the 30, 60, 90, and 120 s treatment groups, respectively. After 30 days' aging, the IFSS for the 30, 60, 90, and 120 s treatment groups lowered 24, 22, 10, and 9%, respectively. Increasing the plasma treatment time will increase the thickness and saturation degree of the oxidized layer on the polymer surfaces, which might hinder the migration of the hydrophobic polar functional groups from the surface to the bulk of the polymer after the plasma treatment. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Proton‐conducting polyhedral oligosilsesquioxane nanoadditives for sulfonated polyphenylsulfone hydrogen fuel cell proton exchange membranes
Authors: Hartmann‐Thompson Claire , Merrington Adrian , Carver Peter I. , Keeley Douglas L. , Rousseau Joseph L. , Hucul Dennis , Bruza Kenneth J. , Thomas Lowell S. , Keinath Steven E. , Nowak Robert M. , Katona Denise M. , Santurri Pasco R.
Published: July 2008

Three novel polyhedral oligosilsesquioxane (POSS) nanofillers functionalized with proton‐conducting sulfonic acid groups, mixed sulfonic acid and alkyl groups, and phosphonic acid groups were synthesized, characterized by IR, 1H and 13C NMR, and MALDI‐TOF MS, and formulated into sulfonated polyphenylsulfone (S‐PPSU) carrier polymers. High quality films were cast from 1‐methyl‐2‐pyrrolidinone (NMP), and through‐plane and in‐plane proton conductivity, mechanical properties, water uptake, dimensional stability, and leaching behavior were measured to assess their suitability for use as hydrogen fuel cell proton exchange membranes. Various nanofiller loadings and S‐PPSU sulfonation levels were studied. The morphologies of the composite membranes were determined by TEM and SEM X‐ray mapping. When compared with Nafion®, the POSS‐S‐PPSU composite membranes exhibited comparable proton conductivity in combination with superior dimensional stability, heat resistance, and mechanical strength. When compared with control S‐PPSU membranes, the composite POSS‐S‐PPSU membranes exhibited superior conductivity, comparable dimensional stability, and slightly decreased mechanical strength. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Preparation and characterization of water‐soluble polyacrylate sodium modified by organomontmorillonite
Authors: Peng Xiaohong , Li Li , Peng Xiaochun
Published: July 2008

Water‐soluble high intrinsic viscosity organomontmorillonite modified polyacrylate sodium (OMMT‐modified PNaA) was prepared via an in situ intercalation adiabatic polymerization of sodium acrylate in the presence of OMMT. The FTIR and XRD analyses correspond to the OMMT‐modified PNaA with exfoliated structure of OMMT. The influences of prepared conditions on intrinsic viscosity and dissolving time of the modified polymers had been investigated in this study. It was found that the incorporation of as little as 0.1 wt % of OMMT added to PNaA matrix could be effective to enhance intrinsic viscosity of the modified PNaA. TGA and DSC studies confirmed the enhancement of the thermal stability of the OMMT‐modified PNaA when compared with PNaA. Furthermore, the solution behavior studies of the modified PNaA showed the “antipolyelectrolyte” effect and high “antishearing” property. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis, characterization, and biodegradation of carboxymethylchitosan‐g‐medium chain length polyhydroxyalkanoates
Authors: Bhatt Rachana , Panchal Bijal , Patel Kamlesh , Sinha Vijay Kumar , Trivedi Ujjval
Published: July 2008

Grafting of medium chain length polyhydroxyalkanoates (mcl‐PHA) produced by Comamonas testosteroni onto carboxymethylchitosan (CMCH) using ceric ammonium nitrate (CAN) as an initiator was carried out under nitrogen atmosphere in aqueous medium. The grafting composition was 2 g CMCH, 0.2M CAN, and 0.5 g mcl‐PHA. The reaction was carried out at 40°C ± 1°C for 4.5 h, and reaction product was extracted by acetone precipitation. The CMCH‐g‐mcl‐PHA copolymers were characterized by Fourier transform infrared spectroscopy, Thermogravimetric analysis, differential scanning calorimetry, and scanning electron microscopy. The data obtained showed successful grafting of mcl‐PHA onto CMCH polymer. TGA results indicated that the graft was stable up to 380°C, and the solubility studies revealed a high % grafting efficiency. Biodegradation studies of the graft in terms of microbial growth, extracellular protein concentration, and % weight loss in the graft were carried out for 30 days using a bacterial isolate Burkholderia cepacia 202 and a fungal isolate Aspergillus fumigatus 202. 93% weight loss of the graft was obtained in case of A. fumigatus 202, whereas B. cepacia 202 showed 76% loss in weight of the graft. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Preceramic polymer for SiBNC fiber via one‐step condensation of silane, BCl3, and silazane
Authors: Tang Yun , Wang Jun , Li Xiao‐Dong , Wang Hao , Li Wen‐Hua , Wang Xiao‐Zhou
Published: July 2008

A preceramic polymer for SiBNC fiber, polyborosilazane, has been synthesized by one‐step condensation reaction of dichloromethylsilane, BCl3, and hexamethyldisilazane with high yield. The reaction mainly involves the condensation of SiCl and BCl with NSiMe3 followed by SiMe3Cl evaporation and dehydrogenation between NH and SiH. The resulted polymer is a soluble colorless transparent solid with melting point of 70°C and molecular weight of 10,800. The backbone of the polymer is mainly composed of SiNB‐bridge with some borazine rings. The polymer exhibits good processability and flexible polymer fibers with diameter of 15–20 μm were obtained by melt spinning. Pyrolysis of the as‐synthesized polymer to 1000°C under nitrogen atmosphere results in a ceramic yield of 63 wt %, and the obtained SiBNC ceramic remains fully amorphous up to 1700°C, and only small amount of poorly crystallized BN, Si3N4, and SiC phases were observed upon heating at 1850°C. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Prediction of the twisting moment and axial force in a circular rubber cylinder for combined extension and torsion based on the logarithmic strain approach
Authors: Kakavas P. A. , Giannopoulos G. I. , Vassilopoulos A. P.
Published: July 2008

The scope of the present work is the application of a particular class of strain energy function, based on the logarithmic strain, for the prediction of the twisting moment and axial force of a rubber circular cylinder under combined extension and torsion. The strain energy function involves four material parameters three of which are determined by fitting published experimental data from simple tensile and compression tests of natural rubber. One of the parameters of the proposed model has physical meaning, and it is equal to one ninth of the initial modulus of elasticity of the material. Hence, the number of unknown parameters is reduced to three. The logarithmic strain energy function is then applied to a combined extension and torsion problem of a rubber circular cylinder to check its performance for more complicated deformations. The results are compared with corresponding experimental and theoretical solutions available in the literature to validate the proposed model. It is found that the proposed strain energy function apart from predicting the common modes of deformations is also capable to determine more complicated types of deformation. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Nonisothermal and isothermal crystallization kinetics of nylon‐12
Authors: McFerran Neil L. A. , Armstrong Cecil G. , McNally Tony
Published: July 2008

The isothermal and nonisothermal crystallization behavior of Nylon 12 was investigated using differential scanning calorimetry (DSC). An Avrami analysis was used to study the isothermal crystallization kinetics of Nylon 12, the Avrami exponent (n) determined and its relevance to crystal growth discussed and an activation energy for the process evaluated using an Arrhenius type expression. The Lauritzen and Hoffman analysis was used to examine the spherulitic growth process of the primary crystallization stage of Nylon 12. The surface‐free energy and work of chain folding were calculated using a procedure reported by Hoffmann and the work of chain folding per molecular fold (σ) and chain stiffness of Nylon 12 (q) was calculated and compared to values reported for Nylons 6,6 and 11. The Jeziorny modification of the Avrami analysis, Cazé and Chuah average Avrami parameter methods and Ozawa equation were used in an attempt to model the nonisothermal crystallization kinetics of Nylon 12. A combined Avrami and Ozawa treatment, described by Liu, was used to more accurately model the nonisothermal crystallization kinetics of Nylon 12. The activation energy for nonisothermal crystallization processes was determined using the Kissinger method for Nylon 12 and compared with values reported previously for Nylon 6,6 and Nylon 11. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Compatibilization and properties of SAN/EPDM blends with the addition of coagents
Authors: Taheri Mona , Morshedian Jalil , Esfandeh Masoud
Published: July 2008

SAN and EPDM are not miscible. In this work, the dry blending of SAN and EPDM using Centrex (acrylonitrile/EPDM/styrene graft copolymer) and EPMMA (EPDM‐g‐Mah) as coagents was studied. Centrex content was used at 6–20 wt %. EPMMA content in the mixture was 20 wt %. The effects of coagent type and content on the mechanical properties and morphology were investigated. SEM micrographs of SAN/EPDM/Centrex and SAN/EPDM/EPMMA blends showed that both Centrex and EPMMA have an effective role in forming a finer morphology. For the ternary blends, the addition of coagent resulted in a significant reduction in the size of the dispersed phase. The mechanical properties of SAN/EPDM/coagent blends were improved significantly in comparison to the simple SAN/EPDM blends. SAN/EPDM/Centrex blends showed higher stress‐at‐break and SAN/EPDM/EPMMA blends showed higher impact strength. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis and in situ foaming of biodegradable malonic acid ESO polymers
Authors: Doğan Engin , Küsefoğlu Selim
Published: July 2008

In this study, biodegradable rigid cellular materials were synthesized from the reaction of malonic acid with epoxidized soybean oil. Malonic acid reacts with two epoxy groups to give a network polymer. In the course of this reaction, initially formed malonic acid monoester (MAME) can decarboxylate and produce CO2, which acts as the blowing agent leading to in situ foaming of the polymer. Epoxide addition and decarboxylation reactions of MAME occur competitively and simultaneously and by controlling their relative rates, foams of controlled density were produced. 1H NMR spectrum of the synthesized foams showed that increasing the temperature increases the rate of decarboxylation reaction of MAME and decreases crosslink density leading to softer and lower density foams. Addition of 1,4‐diazabicyclo[2.2.2]octane (DABCO) as a catalyst also increases the rate of decarboxylation. Load deflection curves of the cellular materials showed that decreasing the temperature and addition of DABCO increase compressive modulus of samples. Cell morphology was studied by microscopic images of foam samples that showed that foam samples have a closed cell structure and a wide distribution of cell volume. Soil burial test was done to determine rate of biodegradation of foam samples. A half‐life of 815 days showed that foam samples are highly biodegradable. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Preparation of a multistructural film with CM‐chitosan and PVA, and in vitro ornidazole release from the carrier
Authors: Wang Ling Chong , Chen Xi Guang , Sheng Liu Cheng , De Li Li , Xia Ji Qiu , Jun Yu Le
Published: July 2008

In this study, carboxymethyl‐chitosan microspheres (CCMS) were prepared by a method of emulsification combined with two‐step solidification and loaded ornidazole as model drug. The ornidazole loaded CCMS were incorporated into Poly(vinyl alcohol) (PVA) film to form a multistructure drug system for feasibly releasing drug in local site. The appearance, particle size, drug loading and encapsulation efficiency, and drug release profiles of CCMS could be tailored in the preparation. Appropriate enhancement of drug amount in the microsphere would bring optimum effect on drug loading percentage and release profile. The use of dimethylsulfoxide (DMSO) could produce spherical spheres with smooth surface and small size, but depress the drug loading and encapsulation efficiency and hasten the burst drug release. For the multistructure carrier materials, the outer PVA film rapidly breaks up to pieces after about 30 min of placement in water and then entirely dissolved. Drug release from the multistructure carriers was a little faster than that from the pure CCMS. Ornidazole release from the carriers performed a burst release in the initial 2 h then followed a gradual release. It could be achieved the controlled release pattern of ornidazole by dispersing the well prepared CCMS into PVA film. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Polymer micro or nanofibers for optical device applications
Authors: Yang Qing , Jiang Xiaoshun , Gu Fuxing , Ma Zhe , Zhang Jiangyang , Tong Limin
Published: July 2008

Silica taper incorporated polymer micro or nanofibers have been fabricated by direct drawing. This method could provide stable and high‐optical‐coupling efficiency. The as‐fabricated polymethyl methacrylate (PMMA) fibers not only show low‐optical losses, but also offer good flexibility, making them promising elements for sharp‐bending waveguides and ring resonators. A low‐loss microcoupler has been assembled with two 860‐nm‐diameter PMMA fibers and a polymeric knot resonator with a loaded Q‐factor of about 3000 has been assembled using a 3‐μm‐diameter PMMA microfiber. Thermostability of the PMMA fibers has also been investigated. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Comparison of mechanical properties of PP/SEBS blends at intermediate and high strain rates with SiO2 nanoparticles vs. CaCO3 fillers
Authors: Mae Hiroyuki , Omiya Masaki , Kishimoto Kikuo
Published: July 2008

The present article focuses on the effect of two types of inorganic fillers (SiO2 and CaCO3) on the mechanical properties of PP/SEBS blend. The nominal particle diameters of SiO2 and CaCO3 are 7 nm and 1 μm, respectively. The studied blend ratios were PP/SEBS/SiO2 (CaCO3) = 75/22/3 and 73/21/6 vol %. The morphology of polymer blends was observed and the distributions of the SEBS, SiO2, and CaCO3 particles were analyzed by transmission electron microscopy (TEM). Tensile tests were conducted at nominal strain rates from 3 × 10−1 to 102 s−1. The apparent elastic modulus has the local strain‐rate dependency caused by SiO2 nanoparticles around SEBS particles in the blend of PP/SEBS/SiO2. The yield stress has weak dependency of morphology. The absorbed strain energy has strong dependency of the location of SiO2 nanoparticle or CaCO3 fillers and SEBS particle in the morphology. It is considered that such morphology, in which inorganic nanoparticles are located around SEBS particles, can prevent the brittle fracture while the increased local strain rate can enhance the apparent elastic modulus of the blend at the high strain rate. On the basis of the results of this study, the location and size of inorganic nanoparticles are the most important parameters to increase the elastic modulus without decreasing the material ductility of the blend at both low and high strain rates. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Rheology of 1‐butyl‐3‐methylimidazolium chloride cellulose solutions. I. Shear rheology
Authors: Sammons R. J. , Collier J. R. , Rials T. G. , Petrovan S.
Published: July 2008

In this article, shear rheology of solutions of different concentrations obtained by dissolution of cellulose in the ionic liquid (IL) solvent 1‐butyl‐3‐methylimidazolium chloride ([Bmim]Cl) was studied by measuring the complex viscosity and dynamic moduli at different temperatures. The obtained viscosity curves were compared with those of lyocell solutions and melt blowing grade polypropylene melts of different melt flow rates (MFR). Master curves were generated for complex viscosity and dynamic moduli by using Carreau and Cross viscosity models to fit experimental data. From the Arrhenius plots of the shift factors with respect to temperature, the activation energies for shear flow were determined. These varied between 18.99 and 24.09 kCal/mol, and were compared with values for lyocell solutions and different polymeric melts, such as polyolefins, polystyrene, and polycarbonate. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Polythiophene gold nanoparticles composite film for application to glucose sensor
Authors: Pandey Pratibha , Arya Sunil K. , Matharu Zimple , Singh S. P. , Datta Monika , Malhotra B. D.
Published: July 2008

Regioregular poly‐3‐hexylthiophene (regP3HT) and dithiobissuccinimidyl propionate (DTSP) have been used to prepare bifunctionalized gold nanoparticles (Bf AuNPs). Processable properties of regP3HT have been used to obtain regP3HT‐AuNPs‐DTSP film on a gold‐coated glass surface and the succinimidyl group of DTSP in this regP3HT‐AuNPs‐DTSP/Au electrode has been utilized for covalent immobilization of glucose oxidase (GOx). The UV‐visible (UV‐vis), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopic studies have been used to characterize regP3HT‐AuNPs‐DTSP/Au and GOx‐regP3HT‐AuNPs‐DTSP/Au electrode, respectively. This GOx‐regP3HT‐AuNPs‐DTSP/Au bioelectrode shows response time of 10 s, linearity from 25 to 300 mg/dL of glucose and the value of Michaelis‐Menten constant as 5.85 mM (105.3 mg/dL). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Branched poly(p‐phenylenevinylene): Synthesis, optical and electrochemical properties
Authors: Huo Lijun , Hou Jianhui , Zhou Yi , Han Minfang , Li Yongfang
Published: July 2008

A series of poly(p‐phenylene vinylene) (PPV) derivatives with phenylene vinylene side chains (branched PPVs), PPV0, PPV1, PPV2, and PPV3, were synthesized by the Heck coupling reaction and characterized by TGA, absorption spectra, photoluminescence (PL) spectra, and electrochemical cyclic voltammetry. The branched PPVs showed two absorption peaks in the UV–vis region, corresponding to the conjugated side chains (UV absorption) and the main chains (the visible absorption). Especially the absorption spectrum of PPV3 covers a broad wavelength range from 300 to 500 nm. Introducing the electron‐donating alkoxy substituents on the PPV main chains and increasing the content of the alkoxy groups lead to bathochromic shift of both absorption and PL spectra from PPV1 to PPV2 to PPV3. The onset oxidation potential of the branched PPVs is lower by 0.1–0.2 V than that of PPV, indicating that the electron‐donating ability of the branched PPVs enhanced in comparison with that of PPV. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Gas permeation properties of polyvinylchloride/polyethyleneglycol blend membranes
Authors: Sadeghi M. , Pourafshari Chenar M. , Rahimian M. , Moradi S. , Dehaghani A. H. Saeedi
Published: July 2008

In this study, the effect of the molecular weight of polyethyleneglycol (PEG) on the gas permeability and selectivity of a series of polyvinylchloride/polyethyleneglycol (PVC/PEG) blend membranes was investigated. The molecular weight of polyethylene glycol ranged from 400 to 4000. PVC/PEG blend membranes were prepared via thermal phase inversion of PVC/PEG/dimethylformamide solution at 60°C. The permeabilities of pure CO2, CH4, O2, and N2 gases through prepared membranes were determined at room temperature (25°C) and 20 bar feed pressure. The blend membranes having PEG with 4000 molecular weight showed higher values of CO2 permeability, and CO2/CH4 and CO2/N2 ideal selectivities (the ratio of pair gas permeabilities) compared with other blend membranes containing PEGs of lower molecular weights. It was also found that the gas permeabilities of PVC/PEG4000 blend membrane rapidly increased with an increase in PEG concentration (weight fraction). The PVC/PEG blends containing 10, 20, and 30 wt % of PEG4000 showed CO2 permeabilities equal to 0.84, 2.38, and 5.82 Barrer (1 Barrer = 10−10 cm3 (STP) cm/cm2 s cmHg), respectively. The CO2/N2 ideal selectivities of 10, 20, and 30 wt % of PEG4000/PVC blend membranes were 49, 70, and 109, respectively. This is a great improvement compared with the pure PVC membrane, which showed CO2 permeability and CO2/N2 ideal selectivity of 0.13 Barrer and 14.5, respectively. These results and comparison of CH4 and N2 permeabilities of PVC membrane and PVC/PEG blend membranes indicated that the gas solubility is dominant in the permeation of gases through abovementioned blend membranes. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis and properties of novel soluble polychloro substituted aromatic polyamides
Authors: Sheng Shou‐Ri , Liu Zhuo , Liu Xiao‐Ling , Liu Yan , Song Cai‐Sheng
Published: July 2008

A novel monomer of tetrachloroterephthaloyl chloride (TCTPC) was prepared by the chlorination of terephthaloyl chloride catalyzed by ferric chloride at 175–180°C for 10 h, and confirmed by FTIR, MS, and elemental analysis. A series of new polychloro substituted polyamides with inherent viscosities of 1.17–1.28 dL/g have been prepared from TCTPC with various aromatic diamines. All the polyamides were amorphous and readily soluble in polar solvents such as NMP, DMAc, DMF, and DMSO at room temperature, and could afford flexible and tough films via solution casting. The cast films exhibited good mechanical properties with tensile strengths of 83.6–106.8 MPa, elongations at breakage of 3.9–7.1%, and tensile modulus of 2.28–3.98 GPa. These polyamide films also exhibited good thermal stability with the glass transition temperature of 250–284°C, the temperature at 5% weight loss of 470–504°C and high char yields of 57.8–59.7% in nitrogen. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Quantitative Analysis and Localization of mRNA Transcripts of Type I Collagen, Osteocalcin, MMP 2, MMP 8, and MMP 13 During Bone Healing in a Rat Calvarial Experimental Defect Model
Authors: Itagaki Tomoko , Honma Takahiro , Takahashi Ichiro , Echigo Seishi , Sasano Yasuyuki
Published: July 2008

The study examined the expression of matrix metalloproteinases (MMPs), type I collagen and osteocalcin during bone healing in a rat calvarial experimental defect model. Twelve‐week‐old male Wistar rats were used. A full‐thickness standardized trephine defect was made in the parietal bone, with the rat under anesthesia. RNA was extracted from tissue that filled the original bone defect on days 1 and 3 and in weeks 1, 2, 3, 5, 8, 10, 12, 18, and 24 and processed for quantitative analysis of expression of type I collagen, osteocalcin and matrix metalloproteinases (MMPs) 2, 8, and 13 by using real‐time polymerase chain reaction. Alternatively, the rats were fixed by perfusion through the aorta and resected calvaria were processed for in situ hybridization for these molecules. The expression of type I collagen, osteocalcin and MMPs 2 and 13 increased toward week 2 and decreased thereafter, whereas the expression of MMP 8 was the highest on day 1. The mRNA transcripts of type I collagen and osteocalcin were localized in osteoblasts and osteocytes, some of which expressed MMPs 2, 8, and 13. Osteoblasts and osteocytes may play a role in the remodeling of extracellular matrices with MMPs during healing of a defect in bone. Anat Rec, 291:1038–1046, 2008. © 2008 Wiley‐Liss, Inc.
Nasal Fossa of Mouse and Dwarf Lemurs (Primates, Cheirogaleidae)
Authors: Smith Timothy D. , Rossie James B.
Published: July 2008

Dimensions of the external midface in mammals are sometimes related to olfactory abilities (e.g., “olfactory snouts” of strepsirrhine primates). This association hinges on the largely unexplored relationship between the protruding midface and internal topography of the nasal fossae. Herein, serially sectioned heads of embryonic to adult cheirogaleid primates (mouse and dwarf lemurs) and a comparative sample were studied. To assess the anteroposterior distribution of olfactory epithelium (OE) within the nasal fossa, the surface area of OE and non‐OE was measured in two mouse lemurs (one adult, one infant). Prenatally, ethmoturbinal projections appear in an anteroposterior sequence. Fetal mouse lemurs, tenrecs, voles, and flying lemurs have four ethmoturbinals that project toward the nasal septum. Major distinctions among these mammals include the number of turbinals in recesses and the extent of the olfactory recess. Surface area measurements in the adult mouse lemur reveal that 31% of the entire nasal fossa is lined with OE. The majority is sequestered in a posterior recess (70% OE). Anterior to this space, only 28% of the nasal fossa is lined with OE. Ethmoturbinal I is lined with relatively less OE (35%) compared with more posterior ethmoturbinals (46–57%). Age comparisons support the idea that OE increases less than non‐OE between ages. Regionally, results suggest that most growth in surface area occurs in turbinals. But in all ethmoturbinals, surface area of non‐OE differs between ages more than that of OE. This study shows that the anterior part of the nasal fossa is mostly nonolfactory in Microcebus murinus. Anat Rec, 291:895–915, 2008. © 2008 Wiley‐Liss, Inc.
The Nasal Fossa of Mouse and Dwarf Lemurs (Primates, Cheirogaleidae)
Authors: Smith Timothy D. , Rossie James B.
Published: July 2008

Ventral view of a computer‐generated, 3D reconstruction of the nasal capsule in a 16 mm CRL Microcebus murinus. The position of the eyes is lateral to the nasal capsule. See Smith et al., Anatomical Record 291:895–915.
Mapping the cellular network of the circadian clock in two cockroach species
Authors: Wen Chih‐Jen , Lee How‐Jing
Published: July 2008

The German cockroach, Blattella germanica, and the double‐striped cockroach, B. bisignata, are sibling species with a similar period sequence but a distinctive circadian rhythm in locomotion. The cell distribution of immunoreactivity (ir) against three clock‐related proteins, Period (PER), Pigment Dispersing Factor (PDF), and Corazonin (CRZ), was compared between the species. The PER‐ir cells tend to form clusters and are sprayed out in the central nervous system. Three major PER‐ir cells are located in the optic lobes, which are the sites of the major circadian clock. They are interconnected with PER‐ir axon bundles. Interestingly, the potential output signal of the circadian clock, PDF, is co‐localized with PER in all three groups of cells. However, only two CRZ‐ir cells and their axons are found in the optic lobes and they are not co‐localized with PER‐ir or PDF‐ir cells and axons. Since only one circadian rhythm is expressed in locomotion, the time signals from both major clocks in optic lobes are coupled by connection with PDF‐ir axons. A group of 3–4 PER‐ir cells in the protocerebrum display typical characteristics of neurosecretary cells. In addition, there are numerous, small PER‐ir and PDF‐ir co‐localized cells in the pars intercerebralis (PI), which have direct connections with the neurohemoorgan, corpora cardiaca, through PER‐ir and PDF‐ir axons. Based on these findings, the cellular connection shows a circadian control through the endocrine route. For the rest of central nervous system, only a few PER‐ir and PDF‐ir cells or axons are detected. This finding implies the circadian clock for locomotion is not located in subesophageal ganglion, thoracic or abdominal ganglia, but may use other neural messengers to pass on circadian signals. Since the overall distribution pattern of the clock cells are the same for B. germanica and B. bisignata, the possible explanation for the different expressions of locomotion between the species depends on genes downstream of per, pdf, and crz. Arch. Insect Biochem. Physiol. 68:215–231, 2008. © 2008 Wiley‐Liss, Inc.
Characterization of midgut trypsinogen‐like cDNA and enzymatic activity in Plutella xylostella parasitized by Cotesia vestalis or Diadegma semiclausum
Authors: Shi Min , Huang Fang , Chen Ya‐Feng , Meng Xiang‐Feng , Chen Xue‐Xin
Published: July 2008

Protein digestion in insects is a result of the action of a complex of proteinases present in the midgut. In this report we describe the cloning and sequencing of a trypsin cDNA from larvae of the lepidopteran herbivore Plutella xylostella. We investigated the expression of this gene and enzymatic activity of its translation product with N‐a‐benzoyl‐l‐arginine p‐nitroanilide (BApNA) as substrate in P. xylostella larvae that were either unparasitized or parasitized by Cotesia vestalis or Diadegma semiclausum parasitoids. The full cDNA sequence consisted of an open reading frame (ORF) encoding 273 amino acid residues including 23 residues of a signal peptide, and the predicted mature trypsinogen‐like enzyme had a molecular mass of 26.5 kDa. The amino acid sequence of this trypsinogen‐like enzyme protein and phylogenetic relationship with other published trypsin enzyme proteins suggested that it may be a new proteinase in the trypsin protein family. Parasitism of D. semiclausum did not significantly change the mRNA transcript level or BApNAase activity in host larvae. By contrast, parasitization by C. vestalis induced higher transcript levels coupled with a higher level of BApNAase activity. The BApNAase activity in the midgut of nonparasitized or parasitized P. xylostella larvae increased to a maximum level at pH 12, and the parasitism by both C. vestalis and D. semiclausum increased sensitivity of the enzyme to pH values ranging from 2 to 9.5. These parasitoid‐induced changes may represent host manipulation by the developing parasitoid larva. Arch. Insect Biochem. Physiol. 2008. © 2008 Wiley‐Liss, Inc.
Juvenile hormone induction of glutathione S‐transferase activity in the larval fat body of the common cutworm, Spodoptera litura (Lepidoptera: Noctuidae)
Authors: Wu Ming‐Cheng , Lu Kuang‐Hui
Published: July 2008

The effect of pyriproxyfen, a juvenile hormone analog (JHA), on the pupation of S. litura was examined. A topical application of 100 μg JHA/larva on the newly ecdysed (0‐day) sixth instar larvae resulted in more than 80% pupation, while most of the 1‐ or 2‐day‐old larvae similarly treated developed into supernumerary larvae. Glutathione S‐transferse (GST) activity in the fat body of 0‐day‐old sixth instar larvae was significantly induced within 12 h of JHA (100 μg/larva) treatment. In contrast, no such induction was found when 1‐ and 2‐day‐old sixth instar larvae were similarly treated. This induction phenomenon was also observed when 0‐day‐old sixth instar larvae were treated with the natural JH III. The suppressive effects of α‐amanitin and cycloheximide suggest that JHA induction of GST activity in these cutworm larvae presumably occurred at the gene transcription level. Arch. Insect Biochem. Physiol. 68:232–240, 2008. © 2008 Wiley‐Liss, Inc.
Preface: Insect science in Taiwan
Authors: Lee How‐Jing
Published: July 2008

When Dr. David Stanley presented a short course in the Department of Entomology, National Taiwan University, last year, he had the opportunity to observe first‐hand the activities and potential of entomological research in Taiwan. A special issue of this journal devoted solely to the representation of insect biochemical and physiological research in Taiwan should be an eye‐opener for the international entomological community. Therefore, this is a platform setup for Taiwanese entomologists to introduce the past, present, and future of Insect Science in Taiwan to our international colleagues. The germination of Entomology in Taiwan started during the Japanese Occupation (1895–1964). The Japanese helped lay a solid background for research on insect faunal inventories, crop protection, and medically important insects. In the continuous co‐evolutionary game of survival with insects, the Taiwanese received the baton from their Japanese occupiers and ran with it for their own existence and scientific success.
Synthesis and Cytotoxicity Testing of Novel 2‐(3‐Substituted‐6‐chloro‐1,1‐dioxo‐1,4,2‐benzodithiazin‐7‐yl)‐3‐phenyl‐4(3H)‐quinazolinones
Authors: Pomarnacka Elzbieta , Maruszak Magdalena , Langowska Karolina , Reszka Przemyslaw , Bednarski Patrick J.
Published: July 2008

A new series of thirteen 2‐[3‐(substituted amino)‐6‐chloro‐1,1‐dioxo‐1,4,2‐benzodithiazin‐7‐yl]‐3‐phenyl‐4(3H)‐quinazolinones 4‐16 were prepared in order to evaluate their cytotoxic activity against 12 human cancer cell lines. The bioassay indicated that the quinazolinone derivatives 5, 8–12, 15, and 16 possess cancer‐cell growth‐inhibitory properties. Compounds 5 and 12 showed a high level of selectivity for certain cell lines. The most active compounds 9, 10, 15, and 16 showed moderate antiproliferative activity and were approximately 4‐fold less potent than cisplatin.
Structural Modifications of Salicylates: Inhibitors of Human CD81‐Receptor HCV‐E2 Interaction
Authors: Holzer Marcel , Ziegler Sigrid , Neugebauer Alexander , Kronenberger Bernd , Klein Christian D. , Hartmann Rolf W.
Published: July 2008

Starting point of the present paper was the result of a virtual screening using the open conformation of the large extracellular loop (LEL) of the CD81‐receptor (crystal structure: PDB‐ID: 1G8Q). After benzyl salicylate had been experimentally validated to be a moderate inhibitor of the CD81‐LEL–HCV‐E2 interaction, further optimization was performed and heterocyclic‐substituted benzyl salicylate derivatives were synthesized. The compounds were tested for their ability to inhibit the interaction of a fluorescence‐labeled antibody to CD81‐LEL using HUH7.5 cells. No compound showed an increase concerning the inhibition of the protein‐protein interaction compared to benzyl salicylate.
Evidence for the network perspective on organizational learning
Authors: Pahor Marko , Škerlavaj Miha , Dimovski Vlado
Published: July 2008

This article provides evidence for the network perspective on organizational learning in the cases of two companies of different size, industry, and culture. It builds on an earlier article that introduced the network perspective on organizational learning, and proposes some common traits of learning networks and tests them with the help of the tools of social‐network analysis. We find support for the network perspective on organizational learning. There are some traits of the learning network that are common to very different companies, such as the fact that learning occurs mainly in clusters. Some other traits depend much on the organizational culture.