bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and characterization of electrically conducting copolymers based on benzene and biphenyl
Authors: Simitzis Johannis , Triantou Despina , Soulis Spyridon
Published: July 2008

Poly(p‐phenylene) (H‐PPP), which is one of the firstly investigated conducting polymer, has the disadvantage of difficult processability because it is infusible and insoluble. The use of biphenyl instead of benzene leads to ortho‐, meta‐, para‐polyphenylenes (H‐PP) which are more soluble and easier to be processed, however their electrical conductivity is lower. Copolymers of polyphenylenes (C1 and C2) and corresponding homopolymers (H‐PPP and H‐PP) were produced by the oxidative cationic polymerization of benzene and/or biphenyl. The soluble (‐S) and the insoluble (‐I) in chlorobenzene polyphenylenes were separated (H‐PP‐I, H‐PP‐S, C1‐I, C1‐S, C2‐I, and C2‐S) and they were doped with a solution of FeCl3. All polyphenylenes were studied by FTIR, XRD, TGA, and their electrical conductivity with constant current was determined. Pronounced differences between the copolymers and the homopolymers were observed, indicating the different structure of the former. The values of the electrical conductivity of doped insoluble copolymers (10−4 and 10−5 S/cm) are between that of H‐PPP (10−3 S/cm) and H‐PP‐I (10−6 S/cm). The values of the electrical conductivity of doped soluble copolymers (10−5 S/cm) are considerably higher than that of H‐PP‐S (10−9 S/cm). The new electrically conductive polyphenylenes that were produced differ significantly from the corresponding homopolymers and combine good electrical conductivity and solubility. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Preparation and cytocompatibility of chitosan‐modified polylactide
Authors: Xiao Yumei , Li Dongxiao , Chen Xuening , Lu Jian , Fan Hongsong , Zhang Xingdong
Published: July 2008

Chitosan‐modified PLA (CMPLA) was fabricated to improve cytocompatibility of polylactide (PLA). PMAA‐grafted PLA (PMAA‐PLA) was obtained through α‐methacrylic acid (MAA) grafted polymerization on PLA surface with photooxidization and UV irradiation. Steady PMAA‐PLA microparticle suspension with an average size as 172.8 ± 3.6 nm and zeta potential as −95.0 ± 0.6 mV was prepared through solvent volatilization. By static electricity interaction and other interactions between PMAA‐PLA microsparticles and chitosan molecules, CMPLA was obtained. FTIR, XPS, SEM, and zeta potential analyses indicated that CMPLA was modified with chitosan molecules uniformly. Compared with the PLA control, CMPLA adapted to supporting the attachment and proliferation of L929 cells better. The obtained CMPLA was expected to be used as perfect biomaterial for tissue regeneration. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Influence of fiber modification on interfacial adhesion and mechanical properties of pineapple leaf fiber‐epoxy composites
Authors: Lopattananon N. , Payae Y. , Seadan M.
Published: July 2008

Three kinds of surface treatment, that is, the alkalization (5% w/v NaOH aqueous solution), the deposition of diglycidyl ether of bisphenol A (DGEBA) from toluene solution (1% w/v DGEBA), and the alkalization combined with the deposition of DGEBA (5% w/v NaOH/1% w/v DGEBA) were applied to modify interfacial bonding and to enhance mechanical properties of pineapple leaf fiber (PALF) reinforced epoxy composites. The fiber strength and strain were measured by single fiber test and the fiber strength variation was assessed using Weibull modulus. Furthermore, a fragmentation test was used to quantify the interfacial adhesion of PALF‐epoxy composite. It was verified that the interfacial shear strength of modified PALFs was substantially higher than that of untreated PALF by almost 2–2.7 times because of the greater interaction between the PALFs and epoxy resin matrix. The strongest interfacial adhesion was obtained from the fibers that had been received the alkalization combined with DGEBA deposition. Moreover, the flexural and impact properties of unidirectional PALF‐epoxy composites were greatly enhanced when reinforced with the modified PALFs due to an improvement in interfacial adhesion, particularly in the synergetic use of 5% NaOH and 5% NaOH/1% DGEBA. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Preparation of poly(styrene‐block‐acrylamide)/organic montmorillonite nanocomposites via reversible addition–fragmentation chain transfer
Authors: Qu Yuan‐Zhi , Su Yi‐Nao , Sun Jin‐Sheng , Wang Kui‐Cai
Published: July 2008

Using dithioester as a chain‐transfer agent and azobisisobutyronitrile as an initiator, we synthesized amphiphilic poly(styrene‐block‐acrylamide) [P(St‐b‐Am)] by the reversible addition–fragmentation chain transfer (RAFT) polymerization method. To improve the heat stability of the block polymers, amphiphilic P(St‐b‐Am)/organic montmorillonite (O‐MMT) nanocomposites were successfully prepared by the addition of O‐MMT during the preparation of the block polymer. The nanocomposites were tested by gel permeation chromatography, IR spectroscopy, X‐ray diffraction, transmission electron microscopy, and thermogravimetry. As for polystyrene (PSt)/O‐MMT, RAFT polymerization could control the molecular weight and the molecular weight distribution of PSt. PSt/O‐MMT was used as a macro RAFT agent to conduct the polymerization of acrylamide, and P(St‐b‐Am)/O‐MMT nanocomposites were prepared. Nanosize layers of montmorillonite were dispersed in the block polymer matrix, and exfoliative nanocomposites were formed. Therefore, the P(St‐b‐Am)/O‐MMT nanocomposites had a better heat stability than before. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Effects of a silane coupling agent on the exfoliation of organoclay layers in polyurethane/organoclay nanocomposite foams?
Authors: Han Mi Sun , Kim Youn Hee , Han Sung Jae , Choi Seok Jin , Kim Sang Bum , Kim Woo Nyon
Published: July 2008

An attempt was made to synthesize polyurethane (PU)/organoclay nanocomposite foams with high thermal insulation properties. The organoclay was modified by polymeric 4,4′‐diphenylmethane diisocyanate (PMDI) with a silane coupling agent. The structure of the organoclay‐modified PMDI with the silane coupling agent was determined by Fourier transform infrared spectroscopy and nuclear magnetic resonance. Transmission electron micrographs and wide‐angle X‐ray diffraction patterns showed that the interlayer distance increased for the PU/organoclay nanocomposites with the addition of the silane coupling agent. It was expected that the distance between the organoclay layers would increase and that the organoclay would be dispersed on a nanoscale in the PU matrix because of the organic/inorganic hybrid bond formation between the organoclay and silane coupling agent. Compressive and flexural strengths of the PU/silane coupling agent/organoclay nanocomposite foams were similar to those of the PU/organoclay nanocomposite foams. However, the thermal conductivity appreciably decreased from 0.0250 to 0.0230 W/m h °C in the PU/silane coupling agent/organoclay nanocomposite foams. Scanning electron micrographs showed that the cell size of the PU/silane coupling agent/clay nanocomposite foams also decreased. On the basis of these results, it is suggested that the smaller cell size and lower thermal conductivity of the PU/silane coupling agent/organoclay nanocomposite foams were mainly due to enhanced exfoliation of the organoclay layers by the silane coupling reaction. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Effects of styrene oligomers and polymers on the suspension polymerization behavior and properties of expandable polystyrene
Authors: Schellenberg Jürgen
Published: July 2008

Styrene oligomers are formed by a free‐radical mechanism during the thermal polymerization of styrene in storage. The effects of these compounds on the preparation of expandable polystyrene (EPS) were investigated with respect to suspension polymerization behavior and the properties of the impregnated polystyrene beads produced. Styrene dimers and trimers up to concentrations of 0.2 wt % did not affect the stability of the suspension during the polymerization and impregnation stages. Besides differentiated effects on the particle size distributions of the polymers and on the polymerization rate, no chain‐transfer activity of the oligomers was observed, and this confirmed the assignment of chain transfer to the Diels–Alder dimer in the literature. The investigation of the foaming behavior of the pentane‐impregnated EPS beads indicated a significant reduction of the prefoaming density caused by styrene dimers and trimers. This behavior resulted from a decrease in the glass‐transition temperatures of these polymers. The effects of high‐molecular‐weight polystyrene, formed in addition to oligomers during storage by the thermal polymerization of styrene, on the polymerization behavior and polymer properties of EPS were also investigated. The results showed a significant impact on the suspension stability that was dependent on the concentration of the high‐molecular‐weight polystyrene. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Free radical polymerizations of some vinyl monomers in carbon dioxide fluid
Authors: Wang Zi , Yang Ya Jun , Dong Qing Zhi , Hu Chun Pu
Published: July 2008

The effect of pressure ranging from ambient atmosphere to 28.5 MPa on the free radical polymerizations of methyl methacrylate (MMA) in carbon dioxide (CO2) was investigated and discussed. The poly(methyl methacrylate) (PMMA) with high molecular weight was synthesized at quite high conversion of MMA in the polymerization at or below 9.2 MPa, as compared to those polymerized under 11.8–28.5 MPa. A phase transition behavior of MMA‐CO2 binary mixture from homogeneous state to vapor‐liquid equilibrium (VLE) state was observed below 10.51 MPa. In such a VLE system, almost all MMA was found to exist in the liquid phase with higher concentration than that in homogenous system. Thus, the fast polymerization rate of MMA and high molecular weight of PMMA could be related to the VLE state of MMA/CO2 under low pressure. Similar phenomena were also observed in the polymerization systems of styrene and vinyl acetate in CO2, respectively. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Properties of solid solutions of poly(ethylene oxide)/epoxidized natural rubber blends and LiClO4
Authors: Chan C. H. , Kammer H. W.
Published: July 2008

Solid solutions of blends of poly(ethylene oxide) (PEO) and epoxidized natural rubber (ENR) comprising 12 wt % of LiClO4 were studied. Two glass transition temperatures, corresponding to the Tgs of the constituents, confirm immiscibility of the polymers over the entire composition range. It turns out that the Tgs of both polymers slightly increase after addition of salt to the blends. This shift is approximately constant over the whole range of blend composition. Accordingly, Tg measurements reveal that the salt dissolves to approximately equal relative amounts in the two phases. The degree of crystallinity of PEO in blends with ENR descends only to a minor extent with ENR content. However, addition of salt leads first to decreasing crystallinity and second this decrease becomes more pronounced with the addition of ENR. It shows that under these experimental conditions the salt content in PEO increases as compared to ENR. As one expects, the rate of isothermal crystallization does not change in blends as long as PEO is in excess. The situation changes again when salt is added. The rate decreases in a certain range of crystallization temperatures when ENR is added, demonstrating that salt is favorably dissolved in PEO. Conductivity was measured in polymers comprising different salt concentrations. A power‐law dependence of conductivity on salt concentration was found. It results that the mobility of charge carriers in PEO exceeds that of ENR by five orders of magnitude. Therefore, the conductivity in blends is primarily governed by PEO as long as PEO is in excess. Conductivity measurements reveal again that salt is preferably dissolved in PEO. The distribution coefficient is estimated. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Miscibility, thermal, and mechanical studies of hydroxypropyl methylcellulose/pullulan blends
Authors: Prasad P. , Guru G. S. , Shivakumar H. R. , Rai K. Sheshappa
Published: July 2008

Miscibility of blends of hydroxypropyl methylcellulose (HPMC) and Pullulan in common solvent water were studied by viscometry, ultrasonic, density, and refractometric methods at 30 and 40°C. Further the blend films of HPMC and Pullulan were prepared by solution casting method and characterized by Fourier transform IR spectroscopy (FTIR), scanning electron microscopy, tensile measurements, thermogravimetric, and differential scanning calorimetric (DSC) methods. Using the viscosity data, interaction parameters were computed and it suggests that the blend is miscible when the HPMC content is more than 50% in the blend. The change in temperature had no significant effect on the miscibility of HPMC/Pullulan blends. The semimiscibility is confirmed by ultrasonic velocity, density, and refractometric methods. The specific intermolecular interactions of hydrogen bonding type of the blends were investigated by DSC and FTIR. The miscible compositions of HPMC/Pullulan blend showed improved thermal and mechanical properties. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Biodegradable plastics from animal protein coproducts: Feathermeal
Authors: Sharma Suraj , Hodges James N. , Luzinov Igor
Published: July 2008

This work describes the properties of plastics made from partially denatured proteins produced by the animal coproduct (rendering) industry and these plastics' fabrication. Specifically, plastic samples from partially denatured feathermeal protein were successfully produced by a compression‐molding process. The modulus (stiffness) of the material obtained was found to be comparable with that of commercial synthetic materials, such as polystyrene, but was found to have lower toughness characteristics, which is a common phenomenon among plastics produced from animal and plant proteins. A reversible stress–strain property was observed over the yield region. Plastic‐forming conditions for undenatured animal proteins, such as albumen and whey proteins, were also formulated for fabricating plastics out of these proteins' blends with feathermeal proteins. The resultant plastic samples that were developed of biomacromolecular blends, such as feathermeal/whey and feathermeal/albumen, demonstrated improved mechanical properties, specifically tensile strength, when compared with neat plastics from feathermeal proteins. The values for the stiffness of the feathermeal/whey blends deviated from simple mixing rule and showed a synergistic effect. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Ethylene polymerization catalyzed by diamide complexes of Ti(IV) and Zr(IV)
Authors: Carone Carlos L. P. , Fim Fabiana C. , Bisatto Rubens , Jahno Vanusca D. , Lemos Cristóvão , Basso Nara R. S. , Einloft Sandra , Galland Griselda Barrera
Published: July 2008

In this research, we describe the application of the complexes o‐C6H4(NSiMe3)2ZrCl2 (1), o‐C6H4(NSiMe3)2TiBr2 (2), o‐C6H4(NSiMe3)2TiCl2 (3), C2H4(NSiMe3)2ZrCl2 (4), in the ethylene polymerization with different Al/M ratios and temperatures. These complexes presented significant catalytic activities in the presence of methyaluminoxane (MAO) as cocatalyst and toluene as solvent, producing high molecular weight linear polyethylenes. Zirconium complexes were more active at 60°C and titanium complexes at 40°C. Zirconium complex (1) showed the best values of activity (347 kg PE/mol Zr h atm) for Al/Zr ratio of 340 and 60°C of temperature. In ethylene‐1‐hexene copolymerization, the best result was also reached with catalyst 1, at the same conditions. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis, cure kinetics, and thermal properties of the Bis(3‐allyl‐2‐cyanatophenyl)sulphoxide/BMI blends
Authors: Anuradha G. , Sarojadevi M. , Sundararajan P. R.
Published: July 2008

A novel allyl functionalized dicyanate ester resin bearing sulfoxide linkage was synthesized. The monomer was characterized by Fourier Transform Infrared (FT‐IR) Spectroscopy, 1H‐, and 13C Nuclear Magnetic Resonance (NMR) spectroscopy and elemental analysis. The monomer was blended with bismaleimide (BMI) at various ratios in the absence of catalyst. The cure kinetics of one of the blends was studied using differential scanning calorimetry [nonisothermal] and the kinetic parameters like activation energy (E), pre‐exponential factor (A), and the order of the reaction (n) were calculated by Coats‐Redfern method and compared with those calculated using the experimental Borchardt‐Daniels method. The thermal stability of the cured dicyanate, BMI, and the blends was studied using thermogravimetric analyzer. The initial weight loss temperature of dicyanate ester is above 380°C with char yield of about 54% at 800°C. Thermal degradation of BMI starts above 463°C with the char yield of about 68%. Inclusion of BMI in cyanate ester increases the thermal stability from 419 to 441°C. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Kinetic study of atom transfer radical polymerization of methyl methacrylate in ionic liquids
Authors: Zhang Hongyan , Zhang Yumei , Liu Weiwei , Wang Huaping
Published: July 2008

The kinetics of methyl methacrylate (MMA) homopolymerization performed by atom transfer radical polymerization (ATRP) is investigated in detail using ethyl‐2‐bromopropionate (EPN‐Br) as initiator, CuBr as catalyst, and pentamethyldiethylenetriamine (PMDETA) as ligand in ionic liquids (ILs) and acetonitrile. ILs in this research covered two different substitutional imidazolium cations and anions including halogen and halogen‐free ones. The typical cations include 1‐butyl‐3‐methylimidazolium, 1‐ethyl‐3‐methylimidazolium and the typical anions include bromide, tetrafluoroborate. The effects of solvents, temperature, and reaction ingredients ratios on the polymerization kinetics are all investigated in this article and the apparent energy of activation (ΔE) calculated for the ATRP of MMA in 1‐butyl‐3‐methyl‐imidazolium tetrafluoroborate is 6.95 KJ/mol. The number‐average molecular weights (Mn) increase linearly with conversion but are much higher than the theoretical values. It is probably due to the low concentration of deactivator at the early stage of polymerization and the lower bond energy of C‐Br in PMMA‐Br than that in EPN‐Br. Moreover, the catalyst is easily separated from the polymer and the regenerated catalyst is reused for more than three times. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Amino‐functionalized multiple‐walled carbon nanotubes‐polyimide nanocomposite films fabricated by in situ polymerization
Authors: Hu Yizhe , Wu Liping , Shen Jianfeng , Ye Mingxing
Published: July 2008

For the preparation of high‐quality polymeric carbon nanocomposites, it is required that carbon nanotubes are fully compatible with matrix polymers. For this purpose, amino‐functionalized multiple‐walled carbon nanotubes (a‐MWNTs) were synthesized. The a‐MWNTs/polyimide nanocomposite films were prepared through in situ polymerization. According to the spectroscopic characterizations, the a‐MWNTs were homogeneously dispersed in the nanocomposite films as the acid‐functionalized MWNTs. The mechanical properties of the polyimide composite were also studied. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis and characterization of water‐soluble oligosalicylaldehyde‐sulfanilic acid and its Cu(II), Co(II), Pb(II) complexes
Authors: Turac Ersen , Surme Yavuz , Sahmetlioglu Ertugrul , Varol Ramazan , Narin Ibrahim , Toppare Levent
Published: July 2008

This work presents the synthesis and characterization of a new water‐soluble oligophenol derivative, 4‐(2‐hydroxybenzylideneamino)benzenesulfanilic acid (OSAL‐SA) and its metal complexes. The chemical structure of the water‐soluble polymer was characterized by nuclear magnetic resonance (1H NMR) and Fourier transform infrared (FTIR) spectroscopies and thermogravimetric analyses (TGAs). Pb(II), Cu(II), Co(II) complexes of the polymer were also synthesized in methanol. Characterizations of water insoluble polymer‐metal complexes were performed by FTIR, flame atomic absorption spectroscopy, and TGA. The conductivity measurements of OSAL‐SA and polymer–metal complexes were carried out by the four‐probe technique. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Pilling in man‐made cellulosic fabrics, part 1: Assessment of pilling formation methods
Authors: Bui Huong Mai , Ehrhardt Anelise , Bechtold Thomas
Published: July 2008

Despite the pills appear similarly in fabric surfaces, their structure and mechanism of formation are distinct depending on material categories and handling conditions. The lyocell and viscose knitted fabrics were abraded with short cycles in the wet state as an assessment method for pilling formation called rapid pilling test (RPT). The samples were immersed in different wetting agents and subsequently padded before short abrasion in Martindale tester. The results were compared with long abrasion, besides 5–25 cycles of washing and drying (W‐D). The samples were rated and these results were correlated with the changes in the physical parameters obtained in the dry and wet state. The correlation showed the feasibility of RPT in wet state with short‐abrasion cycles, in lieu of long cycles and W–D cycles. Furthermore, the image analysis of single pills formed by different methods and the inner/outer pill structure may reflect the pilling mechanism and yield a comprehensive view of the whole process. Instead of conventional Martindale test, the easy‐handling RPT can be applied for cellulosic fabrics, in which wet samples are abraded in short cycles fulfilling two important demanding factors during test performance: test of material in the wet state and reduced testing time. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Preparation of fine Ni particles and their shielding effectiveness for electromagnetic interference
Authors: Gong Chunhong , Duan Yuping , Tian Juntao , Wu Zhishen , Zhang Zhijun
Published: July 2008

Fine Ni particles with sphere‐like architecture were synthesized via a wet chemical route in distilled water. The resulting fine Ni particles and/or commercial microsized Ni particles were then added to a mixed resin solution to fabricate resin‐based conductive composites. The shielding effectiveness (SE) of the resultant conductive composites for electromagnetic interference was measured as a function of nickel mass fraction. The results indicated that the SE values of the two kinds of Ni‐containing resin‐based composites increased with increasing loading of Ni filler. Moreover, the fine Ni particles, in the absence of any protective agents, were liable to aggregate for the sake of decreasing surface energy, which could be well avoided by ultrasonic disposal. The resin‐based conductive composites containing a low concentration (33.3 wt %) of the ultrasonically disposed fine Ni particles recorded an SE value as much as above 22 dB in a frequency range of 130 MHz to 1.5 GHz, which could not be realized for the composites filled with microsized nickel particles unless the mass fraction of the Ni filler in this case was as high as 50.0 wt %. In other words, the ultrasonically disposed fine Ni particles could be used as efficient lightweight filler for shielding of electromagnetic interference. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Zeolite catalyzed glycolysis of poly(ethylene terephthalate) bottle waste
Authors: Shukla S. R. , Palekar Vikrant , Pingale Navnath
Published: July 2008

Polyethylene terephthalate (PET) bottle waste was depolymerized using excess of ethylene glycol (EG) in the presence of zeolites, β‐zeolite and Y‐zeolite as transesterification catalyst. The glycolysis reaction was carried out under reflux in excess of ethylene glycol up to 8 h. The product of glycolysis was mainly the virtual monomer, bis(2‐hydroxyethyl) terephthalate (BHET) admixed with dimer as residue. The BHET was obtained in pure crystalline form. Influence of the reaction time, PET : EG ratio, type, and concentration of catalyst on the yield of the glycolysis products was investigated. The characterization of the purified monomer was carried out by elemental analysis, melting point, IR spectroscopy, DSC, and NMR. The yield of BHET monomer was more than 60%, which is comparable with the conventionally used heavy metal catalysts such as zinc acetate and lead acetate. This process of glycolysis of PET is economically viable and the catalysts are environment friendly. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Preparation and characterization of silanized silica gel‐supported poly(acrylic acid) network polymer and study of its analytical application as selective extractor for lead ion
Authors: Chowdhury P. , Pandit S. K. , Mandal B.
Published: July 2008

A novel silanized silica gel (SSG)‐supported poly(acrylic acid) network polymer (ion exchanger) has been synthesized and characterized for the study of its analytical applications. The chemical nature of the ion exchanger has been elucidated with the help of FTIR, NMR, TGA, DSC, and SEM. The immobilization of the polymer network on SSG has been studied. The optimum pH range for quantitative extraction of lead was found to be 4.5–6.0. The effects of pH and stripping agent on extraction and elution of Pb(II), respectively, have been investigated. Ion exchange and break through capacity of the exchanger have been determined at room temperature. Pb(II) has been extracted quantitatively from various environmental samples. A plausible mechanism for lead ion exchange has been suggested. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Interfacial modification of high impact polystyrene magnesium hydroxide composites effects on flame retardancy properties
Authors: Chang Suqin , Xie Tingxiu , Yang Guisheng
Published: July 2008

High impact polystyrene (HIPS)/magnesium hydroxide (MH) composites were prepared by melt‐blending. Two kinds of interfacial modifiers were used in this research, maleinated poly[styrene‐b‐(ethylene‐co‐butylene)‐b‐styrene] (SEBS‐g‐MA) triblock copolymer and PS. The effects of the use levels of SEBS‐g‐MA on the flame retardancy of HIPS/elastomer/MH based on unmodified and PS‐modified surface were investigated by TEM, FTIR, and combustion tests (horizontal burning test and cone calorimetry). The combustion results showed that comparing composites containing unmodified MH, the flame retarding properties of composites containing PS‐modified MH were obviously improved. The increased performance can be explained that the PS covered on the surface of MH could further improve dispersion of the filler in matrix. Furthermore, there existed a critical thickness of interfacial boundary for optimum flame‐retarding properties in both ternary composites based MH and PS‐modified MH. When the interfacial boundary relative thickness is less than 0.53, the introduction of SEBS‐g‐MA can improve the dispersion degree, leading the improvement of flame retardancy properties. However, with the increase of interfacial boundary thickness, the SEBS‐g‐MA coating around MH acted as a heat and mass transfer barrier, leading to the reduction of flame retardancy. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Preparation of branched polyacrylonitrile through self‐condensing vinyl copolymerization
Authors: Liu Qingchun , Xiong Ming , Cao Ming , Chen Yongming
Published: July 2008

Branched polyacrylonitrile (PAN) was prepared through a self‐condensing vinyl copolymerization of acrylonitrile and 2‐(2‐bromopropionyloxy)ethyl acrylate (BPEA). The branched architecture of the product was confirmed by NMR spectra and the average degree of branching (DB) was estimated. Through a comparison of the intrinsic viscosity of the product with that of its linear analogue, the contraction factor g′ was calculated. It was found that the viscosity of the branched PAN was obviously lower that that of linear PAN. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Morphology and properties of silane‐modified montmorillonite clays and clay/PBT composites
Authors: Wan Chaoying , Bao Xujin , Zhao Feng , Kandasubramanian Bala , Duggan Matthew P.
Published: July 2008

Commercially available organoclay (Closite 30B) was modified by using 3‐aminopropyltriethoxysilane (APS) via a silylation reaction. Sodium clay (Closite Na) was treated by APS directly as a control. Such modified clays were further melt‐compounded with polybutylene terephthalate (PBT). The morphology and properties of the modified organoclays were characterized with X‐ray diffraction (XRD), transmission electrical microscopy (TEM), Infra‐red spectroscopy, contact angle measurement, and thermogravimetric analysis (TGA). The effects of modified clays on the crystallization behavior of PBT were characterized by differential scanning calorimetry. The basal spacing of Closite Na was enlarged from 1.01 to 1.41 nm after APS treatment, indicating that the APS was intercalated into the clay intergalleries as a monolayer. The basal spacing of Closite 30B increased slightly after APS treatment, partially resulted from the reactions between the APS and hydroxyl groups on the intercalant of Closite 30B. Closite 30B was found to be exfoliated disorderly after melt‐compounded with PBT. The APS‐modified Closite 30B only dispersed as swollen elliptical clay aggregates, in which the silicate layers were orderly intercalated. TGA results showed that the decomposition temperature at 5% weight loss of Closite 30B was increased from 250 to 270°C after APS treatment. A significant increase in the degree of crystallinity of PBT was observed in the exfoliated PBT/30B composite. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Interface and mechanical properties of peroxide cured silicate nanofiber/rubber composites
Authors: Tian Ming , Cheng Lijun , Zhang Liqun
Published: July 2008

Four representative rubber matrices with varying molecular polarity, such as SBR, NBR, EPDM, and CNBR, were reinforced by mechanical blending with γ‐(methacryloxy)proxyltrimethoxy silane (KH570) silanized natural fibrillar silicate (FS)/unmodified FS when dicumyl peroxide was used as a curing agent. The effects of the loading amount of silane coupling agent KH570 and the type of rubber matrix on the dispersion of FS as well as the FS‐rubber interfacial bonding were investigated. The mechanical properties of various rubber composites filled with unmodified FS and silanized FS individually were compared. As indicated by SEM and TEM, unmodified FS showed better dispersion in polar CNBR than in nonpolar SBR, whereas the improvement of the dispersion is more for SBR after the silanization of FS, constructing a stronger filler network. Compared with unmodified FS/rubber composites, silanized FS/rubber composites exhibited a higher interphase crosslinking network as well as a lower loss factor, indicating the improvement of the FS‐rubber interfacial bonding. The more the loading amount of KH570 was, the more the FS‐SBR bonding was improved. Similarly, the improvement of the FS‐rubber bonding was more evident in nonpolar SBR and EPDM after FS was silanized, causing the more increase in mechanical properties, relative to polar NBR and CNBR. In strong molecular polar rubber such as CNBR and NBR, the strong interfacial bonding was achieved even if FS was not silanized with KH570, so that the composites filled with unmodified FS also possessed good mechanical properties. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Influence of microstructure and morphology on stress–strain behavior of commercial high density polyethylene
Authors: Zahedi Mostafa , Ahmadi Mostafa , Nekoomanesh Mehdi
Published: July 2008

In the previous paper (Zahedi et al.,1 J Appl Polym Sci, to appear) the optimal conditions of a new modeling procedure for correlating a scalar response to an input spectrum were established. In this article the developed model is applied to correlate the stress–strain behavior of several commercial high density polyethylene samples to the spectrums of microstructure and morphology. Molecular weight and lamellar thickness distributions were considered as the input spectrums and Young modulus, stress and strain at the yield and break points were considered as the objective responses. The shape of the kernel functions over molecular weight and lamellar thickness distribution spectrums for each mechanical property gives an explanation of how different regions of the spectrums contribute to create the considered property. The simplicity of the procedure facilitates the interpretation of the complex influences and interactions of different structures and morphologies in various aspects of the mechanical performance of the samples. The proposed model can be used in designed experiments with samples of controlled microstructure and morphology to provide detailed information about the structure–property relationships. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Characterization of chitosan/citrate and chitosan/acetate films and applications for wound healing
Authors: Tanigawa Junichi , Miyoshi Norio , Sakurai Kensuke
Published: July 2008

In this work, we aimed to develop a scaffold of chitosan (CS) with a porous sponge structure for an artificial skin. The scaffolds were prepared from both CS/citric and CS/acetic solutions. In addition, the cast films were also prepared from the same solutions to compare some of their properties. They were characterized using WAXD, FTIR, DSC, tensile measurements, and SEM observation. It was found that CS/acetate had low crystallinity but CS/citrate was in an amorphous state, resulting in a large ductility with rubbery softness. Despite the different morphologies of CS/citrate and CS/acetate scaffolds, both scaffolds exhibited the wound healing effect available for tissue engineering. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Electrospun cellulose nanofiber reinforced soybean protein isolate composite film
Authors: Chen Guanfushou , Liu Haiqing
Published: July 2008

This article presents the fabrication of cellulose nanofibrous mats (CNM) reinforced soybean protein isolate (SPI) composite with high visible light transmittance. The CNM was composed of cellulose nanofibers generated from electrospinning technique. The microstructure of the fractured surface of composite films was characterized by scanning electron microscopy (SEM). The light transmittance, mechanical properties, and swelling ratio of CNM/SPI composite were investigated in terms of CNM content in the composite. Because of the ultrafine diameter and superhigh length‐to‐diameter ratio of nanofibers, large amount of cellulose nanofibers fibers distribute in the SPI matrix to form an interpenetrating network (IPN) like composite material. It was found that strong interfacial interactions occurred at the cellulose nanofiber/SPI interfaces. The incorporation of 20 wt % cellulose nanofibers in the SPI matrix resulted in great improvement of mechanical strength and Young's modulus by respectively 13 and 6 times more than neat SPI film. More interestingly, this composite was translucent with light transmittance of over 75% at 700 nm. Furthermore, the swelling ratio of this IPN‐like CNM/SPI composite decreased from 106 to 22% as CNM content increased from 0 to 20 wt %. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Syntheses and properties of cross‐linked polymers from functionalized triglycerides
Authors: Zhao Hui‐Ping , Zhang Jian‐Feng , Susan Sun Xiuzhi , Hua Duy H.
Published: July 2008

A number of functionalized triglycerides were synthesized from glyceryl trioleoate via epoxidation followed by reduction to give glyceryl tris(9‐hydroxy)trioleoate (a triol) or hydrolytic ring opening to obtain glyceryl tris(9,10‐dihydroxy)trioleoate (a hexaol). A selective monoepoxidation reaction of glyceryl trioleoate was also carried out and the resulting monoepoxide was hydrolyzed to give glyceryl 9,10‐dihydroxytrioleoate (a diol). Glyceryl tris(9‐hydroxy)trioleoate was brominated followed by displacement with sodium azide and reduction to give glyceryl tris(9‐amino)trioleoate (a triamine) and glyceryl tris[9‐(N‐isopropylamino)]trioleoate. These functionalized triglycerides were crosslinked with 1,4‐phenylene diisocyanate. The crosslinked polymers exhibit thermoset characteristics. Thermal analysis results suggest that the polymers are in amorphous states, and their thermal stability was significantly affected by crosslink degree. The crosslinked polymer derived from the diol retained 56% of its weight at 408°C, whereas the polymers derived from the aforementioned hexaol with higher crosslink degree retained only 36% of the original weight. Glass transition temperatures of these polymers range from −1.0°C to 10.2°C. The thermal stable polymer, 12, derived from the aforementioned diol exhibits a linear viscoelastic character and can be used as thermoplastics. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Study on superabsorbent composites. XXI. Synthesis, characterization and swelling behaviors of chitosan‐g‐poly(acrylic acid)/organo‐rectorite nanocomposite superabsorbents
Authors: Liu Jianghua , Wang Aiqin
Published: July 2008

A novel chitosan‐g‐poly(acrylic acid)/organo‐rectorite (CTS‐g‐PAA/OREC) nanocomposite superabsorbent was synthesized by aqueous polymerization using N, N′‐methylenebisacrylamide as a crosslinker and ammonium persulfate as an initiator. Rectorite was organified with four different degree of hexadecyltrimethyl ammonium bromide, and the organification of rectorite was proved by FTIR and XRD. The effect of organification degree of rectorite on water absorbency of CTS‐g‐PAA/OREC with different organo‐rectorite content was investigated. The swelling behaviors in distilled water and various pH solutions were also studied. The results from IR spectroscopy and XRD data show that acrylic acid had been grafted polymerization with chitosan and organo‐rectorite and formed nanocomposite. Introducing organo‐rectorite into the CTS‐g‐PAA polymeric network can improved water absorbency and swelling rate of CTS‐g‐PAA/OREC. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Effect of rheological behavior of epoxy during precuring on foaming
Authors: Takiguchi Osamu , Ishikawa Daisaku , Sugimoto Masataka , Taniguchi Takashi , Koyama Kiyohito
Published: July 2008

In this study, the effect of rheological behavior of epoxy during precuring on foaming was investigated. Dynamic time sweep test of epoxy/curing agent (100/1, w/w) was conducted. The viscosities as a function of time showed extremely rapid increase from the order of 102–103 to 106Pa · s at a certain time, followed by slow increase of the viscosities. Dynamic frequency sweep test of precured epoxy with curing agent was conducted at 90°C. The critical gelation time was obtained by using rheological criterion proposed by Winter and Chambon. We found that the slopes of G′(ω) and G″(ω) decreased with increasing precuring time. Correspondingly, tan δ showed a change from negative to positive slope at a critical time. By using the results, the critical gelation time was determined as t = 895–935 s. Samples of epoxy/curing agent/blowing agent (100/1/0.5) were precured for 960–1620 s. And then precured samples were foamed at 230°C for 300 s to decompose chemical blowing agent. The formed bubble size distribution becomes sharp with increase of the precuring time. There are roughly two sizes of bubbles when precured for relatively short time (t < 1080 s) before foaming: large bubbles (>100 μm) and small ones (≅30 μm). On the other hand, foams precured for long time (t > 1200 s) before foaming, large bubbles disappear, and the average diameter of the bubble becomes small while the porosity is low. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Potential applications of poly(vinyl alcohol)‐congo red aqueous solutions and hydrogels as liquids for hydraulic fracturing
Authors: Vega Isabel , Fernández Emiliano , Mijangos Carmen , D'Accorso Norma , López Daniel
Published: July 2008

The authors report on the viscoelastic characterization of guar hydrogels obtained through complexation reactions with borax ions. These gels are compared with hydrogels obtained from poly(vinyl alcohol) of different degree of hydrolysis through complexation reactions with congo red. The effect of the degree of hydrolysis and both, the concentration of PVA and the concentration of congo red, on the viscoelastic properties of the hydrogels is analyzed. The potential use of the PVA‐based hydrogels as hydraulic fracturing liquids is discussed in relation to the commonly used fracturing liquid based on the guar–borax system. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Mechanisms of organophosphate resistance in a field population of oriental migratory locust, Locusta migratoria manilensis (Meyen)
Authors: Yang M.L. , Zhang J.Z. , Zhu K.Y. , Xuan T. , Liu X.J. , Guo Y.P. , Ma E.B.
Published: July 2008

The susceptibilities to three organophosphate (OP) insecticides (malathion, chlorpyrifos, and phoxim), responses to three metabolic synergists [triphenyl phosphate (TPP), piperonyl butoxide (PBO), and diethyl maleate (DEM)], activities of major detoxification enzymes [general esterases (ESTs), glutathione S‐transferases (GSTs), and cytochrome P450 monooxygenases (P450s)], and sensitivity of the target enzyme acetylcholinesterase (AChE) were compared between a laboratory‐susceptible strain (LS) and a field‐resistant population (FR) of the oriental migratory locust, Locusta migratoria manilensis (Meyen). The FR was significantly resistant to malathion (57.5‐fold), but marginally resistant to chlorpyrifos (5.4) and phoxim (2.9). The malathion resistance of the FR was significantly diminished by TPP (synergism ratio: 16.2) and DEM (3.3), but was unchanged by PBO. In contrast, none of these synergists significantly affected the toxicity of malathion in the LS. Biochemical studies indicated that EST and GST activities in the FR were 2.1‐ to 3.2‐fold and 1.2‐ to 2.0‐fold, respectively, higher than those in the LS, but there was no significant difference in P450 activity between the LS and FR. Furthermore, AChE from the FR showed 4.0‐fold higher activity but was 3.2‐, 2.2‐, and 1.1‐fold less sensitive to inhibition by malaoxon, chlorpyrifos‐oxon, and phoxim, respectively, than that from the LS. All these results clearly indicated that the observed malathion resistance in the FR was conferred by multiple mechanisms, including increased detoxification by ESTs and GSTs, and increased activity and reduced sensitivity of AChE to OP inhibition. Arch. Insect Biochem. Physiol. 2009. © 2008 Wiley‐Liss, Inc.
Up‐regulation of lysozyme gene expression during metamorphosis and immune challenge of the cotton bollworm, Helicoverpa armigera
Authors: Zhang Yong , Huang Jianhua , Zhou Bo , Zhang Chunlin , Liu Wenbin , Miao Xuexia , Huang Yongping
Published: July 2008

Lysozymes act as crucial bacteriolytic enzymes in insect immune system by hydrolyzing the β (1→4) bonds between N‐acetylglucosamine and N‐acetylmuramic acid in the peptidoglycan of prokaryotic cell walls. We have isolated and characterized a Helicoverpa armigera cDNA encoding an insect lysozyme named HaLyz. We amplified a fragment by PCR, using degenerate primers derived from the conservative amino acid sequences for performing 5′ and 3′ RACE. The full‐length cDNA was 661 base pairs. The theoretical pI and molecular weight of the protein were computed to be 9.08 and 15.6 kDa, respectively. Prokaryotic expression of the HaLyz ORF by Escherichia coli confirmed the calculated molecular weight of the protein. The deduced 135 amino acids showed high homology with known lysozymes from other insects, ranging from 47% to 89% by BLASTp search in NCBI. Analyses revealed that this protein has a typical lysozyme C signature among amino acids 93–111, CNVTCAEMLLDDITKASTC. An interesting relation between immunity and larva to pupa metamorphosis in insects was discovered. Real time‐PCR showed that HaLyz gene expression was transiently enhanced at the onset of metamorphosis of the cotton bollworm, Helicoverpa armigera. The gene expression was up‐regulated after the injection of E. coli or entomopathogenic fungi, Beauveria bassiana, but showed different expression patterns. Arch. Insect Biochem. Physiol. 2008. © 2008 Wiley‐Liss, Inc.
Annotations on musical scores by performing musicians: Collaborative models, interactive methods, and music digital library tool development
Authors: Winget Megan A.
Published: July 2008

Although there have been a number of fairly recent studies in which researchers have explored the information‐seeking and management behaviors of people interacting with musical retrieval systems, there have been very few published studies of the interaction and use behaviors of musicians interacting with their primary information object, the musical score. The ethnographic research reported here seeks to correct this deficiency in the literature. In addition to observing rehearsals and conducting 22 in‐depth musician interviews, this research provides in‐depth analysis of 25,000 annotations representing 250 parts from 13 complete musical works, made by musicians of all skill levels and performance modes. In addition to producing specific and practical recommendations for digital‐library development, this research also provides an augmented annotation framework that will enable more specific study of human‐information interaction, both with musical scores, and with more general notational/instructional information objects.
Motivation for using search engines: A two‐factor model
Authors: Wu Ling‐Ling , Chuang Ya‐Lan , Chen Pin‐Yuen
Published: July 2008

From a user‐centered perspective, an effective search engine needs to attract new users to try out its features, and retain those users so that they continue using the features. In this article, we investigate the relations between users'motivation for using (i.e., trying out and continuing to use) a search engine and the engine's functional features. Based on Herzberg's two‐factor theory (F. Herzberg, 2003; F. Herzberg, M. Bernard, & B. Snyderman, 1959), the features can be categorized as hygiene factors and motivation factors. Hygiene factors support the query process and provide a basic “task context” for information seeking that allows users to access relevant information. Motivation factors, on the other hand, help users navigate (i.e., browse) and comprehend the retrieved information, related to the “task‐content” aspect of information seeking. Given the consistent findings that hygiene factors induce work motivation for a shorter period of time, it is hypothesized that hygiene factors are more effective in attracting users; while motivation factors are more effective in retaining than in attracting users. A survey, with 758 valid participants, was conducted to test the hypotheses. The empirical results provide substantial support for the proposed hypotheses and suggest that the two‐factor theory can account for the motivation for using a search engine.
Applying the author affiliation index to library and information science journals
Authors: Cronin Blaise , Meho Lokman I.
Published: July 2008

The authors use a novel method—the Author Affiliation Index (AAI)—to determine whether faculty at the top‐10 North American library and information science (LIS) programs have a disproportionate presence in the premier journals of the field. The study finds that LIS may be both too small and too interdisciplinary a domain for the AAI to provide reliable results.