bluuebunny/crossref_metadata_2025 huggingface dataset:
Alginates as binding matrix for bio‐molluscicides against harmful snails Lymnaea acuminata
Authors: Singh Amrita , Singh D. K. , Kushwaha V. B.
Published: April 2007

Various properties of alginates, such as its biodegradability, nontoxicity, biocompatibility, and ability to form gel with a variety of crosslinking agents in mild and aqueous conditions, make it a very useful binding matrix. Use of alginates as binding matrix for bio‐molluscicides (crude Annona squamosa powder and acetogenin extracted from the seed powder of A. squamosa) is explored in this article. Effect of different crosslinkers as well as different loaded concentrations of biomolluscicides on the release were studied The release of the biomolluscicides extended over 25 and 20 days, respectively. The release was affected by the type of crosslinker and the amount of loaded concentration of the molluscicides. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Synthesis and characterization of cardanol‐grafted natural rubber—The solution technique
Authors: Vikram T. , Nando G. B.
Published: April 2007

Cardanol, a by‐product of the cashew industry, has been recently proven to be a multifunctional additive (MFA) in rubbers. It is expected that grafting of cardanol onto natural rubber (NR) would impart inherent MFA characteristics to the rubber. Grafting has been carried out in solution using toluene as the solvent and a peroxide initiator. Optimized conditions of grafting reaction could be arrived at using a statistical tool namely orthogonal array testing strategy, keeping the maximum percentage of grafting as the selection criteria. Further studies were conducted to study the influence of monomer concentration and initiator concentrations. The effect of the reaction temperature and reaction time were also investigated. Characterization of grafted rubber was carried out with the help of infrared spectroscopy, nuclear magnetic resonance spectroscopy and thermal analysis. IR spectrum of cardanol exhibited the characteristic peak of cardanol at 3356 cm−1. Percent grafting (PG) of cardanol onto NR was determined by residual weight method. PG increased with increasing cardanol quantity reached an optimum and then decreased. The increase in reaction time and reaction temperature also caused increasing levels of the grafted cardanol. However, PG continuously increased with increasing initiator concentrations. Differential scanning calorimetry studies of the grafted NR showed a lower glass transition temperature than that of the raw NR, which is indicative of the plasticization effect of cardanol. The thermogravimetric analysis showed a higher thermo oxidative stability for cardanol‐grafted NR. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Comparison of model‐fitting kinetics for predicting the cure behavior of commercial phenol–formaldehyde resins
Authors: Wang Jinwu , Laborie Marie‐Pierre G. , Wolcott Michael P.
Published: April 2007

Phenol–formaldehyde (PF) resins have been the subject of many model‐fitting cure kinetic studies, yet the best model for predicting PF dynamic and isothermal cure has not been established. The objective of this research is to compare and contrast several commonly used kinetic models for predicting degree of cure and cure rate of PF resins. Toward this objective, the nth‐order Borchardt–Daniels (nth‐BD), ASTM E698 (E698), autocatalytic Borchardt–Daniels (Auto‐BD), and modified autocatalytic methods (M‐Auto) are evaluated on two commercial PF resins containing different molecular weight distributions and thus cure behaviors. The nth‐BD, E698, and M‐Auto methods all produce comparable values of activation energies, while Auto‐BD method yields aberrant values. For dynamic cure prediction, all models fail to predict reaction rate, while degree of cure is reasonably well predicted with all three methods. As a whole, the nth‐BD method best predicts degree of cure for both resins as assessed by mean squared error of prediction. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Study of the effects of melt blending speed on the structure and properties of phosphate glass/polyamide 12 hybrid materials
Authors: Urman Kevin , Iverson Douglas , Otaigbe Joshua U.
Published: April 2007

The effects of melt blending conditions on the rheology, crystallization kinetics, and tensile properties of phosphate glass/polyamide 12 hybrid systems were investigated for the first time, to understand their complex processing/structure/property relationships. Increasing amounts of phosphate glass (Pglass) caused an increase in hybrid viscosity. Hybrid viscosity was also affected by processing (melt‐mixing) speed and small‐amplitude oscillatory shear tests and scanning electron microscopy (SEM) were used for a qualitative examination of the hybrid morphology. The addition of Pglass caused a decrease in hybrid crystallinity that was unaffected by processing (melt‐mixing) speed. The two‐parameter Avrami equation was applied successfully to the hybrid systems, and Pglass was found to nucleate the growth of polyamide 12 crystals. The nucleation effect was found to be dependent on concentration and processing history. The tensile properties of the hybrids were also studied, and the Halpin–Tsai equation was applied to the results to determine the maximum packing fraction of the Pglass. These results provide a basis for the prediction of hybrid mechanical properties for different Pglass concentrations and processing histories. Further, because of their facile processibility and desirable characteristics, such as the strong physicochemical interaction between the hybrid components and favorable viscoelasticity, these Pglass/polyamide 12 hybrids can be used as model systems for exploring feasibility of new routes for driving organic polymers and inorganic Pglass to self‐assemble into useful organic/inorganic hybrid materials. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Localized compatibilization in immiscible blends of thermoplastic polyurethane and ethylene‐octylene copolymer
Authors: Wang Jia Sheng , Chen Xu Dong , Mai Bi Yun , Zhang Ming Qiu , Rong Min Zhi
Published: April 2007

To prepare thermoplastic polyurethane (TPU)/ethylene‐octylene copolymer (POE) blends, which are thermodynamically immiscible, maleated POE and aminated POE were incorporated as compatibilizers. Effect of addition of the compatibilizers and their contents on morphology, coalescence, and mechanical properties of TPU/POE blends were investigated. The microstructural observation revealed that the compatibilizers are located at the interface in the blends, forming a stable interfacial layer. As a result, the dispersed phase particle size was greatly reduced and tensile properties of the blends were significantly improved. POE‐NH2 provides the blends with higher compatibility than POE‐MA. The interfacial interaction offered by the compatibilizers was found to be a function of the amount of the reactive groups grafted onto POE. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Applications of rheological torque–time curves to the study of thermooxidative degradation of polypropylene powder
Authors: Wang Xiao , Chen Xiaoyun , Yu Wencan , Ji Yaodong , Hu Xiaobo , Xu Jiarui
Published: April 2007

The torque–time curves of polypropylene (PP) powder treated under various thermooxidative degradation conditions were obtained through processing in the mixing chamber of a rheometer. Meanwhile, the Fourier transform infrared (FTIR) spectra of the corresponding samples were determined, and the quantitative analysis of the carbonyl indices of the FTIR spectra of the samples of the PP powder was carried out to provide evidence for the rheological characterization. PP granules, to which an antideteriorant was added before they were commercially supplied so good antidegradation could be achieved, was investigated for the sake of contrast. The analysis of the experimental results showed that the height of the torque–time curve of the PP powder and the corresponding value of the equilibrium torque could be used to characterize or evaluate the variations of the thermooxidative degradation of the PP powder. Under the same processing conditions, the heights of the torque–time curves of the PP powder and the corresponding values of the equilibrium torque decreased with the enhancement of the thermooxidative degradation treatment before mixing; on the contrary, the heights and areas of the characteristic bands of the carbonyl groups in the FTIR spectra of the PP powder and the corresponding values of the carbonyl index increased. The quantitative analysis of the FTIR spectra provided evidence for the conclusion that the heights of the torque–time curves of the PP powder and the corresponding values of the equilibrium torque could be used to characterize or evaluate the thermooxidative degradation of the PP powder. If the treatment under thermooxidative degradation conditions weakened or the degradation of the PP powder just began (i.e., in the viscosity range for processability), the evaluation method using the heights of the torque–time curves of the PP powder or the corresponding values of the equilibrium torque could provide more sensitivity than the method using the values of the carbonyl index. Consequently, the method using the heights of the torque–time curves to evaluate the thermooxidative degradation of the PP powder had its advantages. The application of the torque–time curves could be used to evaluate not only the variation of the thermooxidative degradation of the PP powder treated under aging conditions before mixing but also the variation of the degradation, including the mechanochemical degradation, of the PP powder during the period of mixing. The dependence of the variation of the degradation of the polymer on the processing time during mixing could be evaluated by the study of the variation of the torque–time curves. It can be concluded that the application of torque–time curves to the evaluation of degradation of PP powder has the advantages of being convenient, real‐time, in situ, online, and production‐oriented. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Preparation and characterization of micron‐sized magnetic microspheres by one‐step suspension polymerization
Authors: Liu Zuli , Liu Cuicui , Yao Kailun , Liu Pandong , Ning Qin
Published: April 2007

Micron‐sized magnetic microspheres with different functional groups were prepared by one‐step suspension copolymerization of styrene, divinyl benzene, and methyl methacrylate in the presence of oleic acid‐coated magnetic nanoparticles. In the present work, we used benzoyl peroxide as an initiator and poly(vinyl alcohol) (PVA‐1788; degree of polymerization: 1,700; degree of hydrolysis: 88%) as a stabilizer. We also added acrylamide (AM) monomer in the aqueous phase and methacrylic acid (MAA) in the oil phase. The morphology and properties of the resulting magnetic microspheres were examined by optical micrographs (OMs), vibrating‐sample magnetometer (VSM), and Fourier transform infrared spectrometer (FT IR). The results showed the three products have uniform and spherical form with superparamagnetism and well dispersion. Moreover, we found that monomer AM had a little contribution to the copolymerization, and MAA could strikingly decrease the diameter of the final microspheres. The magnetic microspheres with functional groups could be linked well with the IgG‐FITC. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Synthesis and characterization of poly(pyridylurea) and poly(pyridylthiourea), potentially semiconducting polymers
Authors: Díaz F. R. , Godoy A. , Moreno J. , Bernède J. C. , Del Valle M. A. , Tagle L. H. , East G. A.
Published: April 2007

Poly(pyridylureas) and poly(pyridylthioureas) were synthesized by reacting 2,6‐diaminopyridine with phosgene and thiophosgene, respectively, using THF and pyridine as solvent. The synthesized polymers were characterized by IR‐spectroscopy, elemental analysis, and X‐ray photoelectron spectroscopy. Thermal stability of the polymers was determined by thermal degradation between 35°C and 700°C. The 50% weight loss of polypyridylureas was above 400°C while for the polypyridylthioureas it was above 450°C. Undoped poly(pyridylureas) and poly(pyridylthioureas) behave as semiconductors, σ = 10−9 (Ω cm)−1. After doping with I2 and SbF5, the electrical conductivity increases several orders of magnitude, σ = 10−7(Ω cm)−1. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
In situ synthesis of iron oxide nanoparticles on poly(ethylene oxide) nanofibers through an electrospinning process
Authors: Faridi‐Majidi Reza , Sharifi‐Sanjani Naser
Published: April 2007

Iron oxide nanoparticle coated poly(ethylene oxide) nanofibers as organic–inorganic hybrids with 200–400‐nm diameters were prepared by the in situ synthesis of iron oxide nanoparticles on poly(ethylene oxide) nanofibers through the electrospinning of a poly(ethylene oxide) solution having Fe2+ and Fe3+ ions in a gaseous ammonia atmosphere. Transmission electron microscopy analysis proved the presence of iron oxide nanoparticles on the polymer nanofibers. The thermal properties of the nanofiber mat were also studied with differential scanning calorimetry and thermogravimetric analysis techniques. X‐ray diffraction showed that the formed iron oxide nanoparticles were maghemite nanoparticles. The results were compared with those of the electrospinning of a poly(ethylene oxide) solution having Fe2+ and Fe3+ ions and a pure poly(ethylene oxide) solution in an air atmosphere. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Synthesis, characterization, and thermal stability of azomethine oligomer and its metal complexes
Authors: Kaya İsmet , Bilici Ali
Published: April 2007

The oxidative polycondensation reaction conditions of N,N′‐bis[(2‐hydroxy‐1‐naphthyl)methylene]urea (2‐HNMU) has been accomplished using NaOCl, H2O2, and air O2 oxidants in an aqueous alkaline medium. The structures of the obtained monomer and oligomer were confirmed by FTIR, UV–vis, 1H NMR, 13C NMR, and elemental analysis. The characterization was made by TG‐DTA, size exclusion chromatography (SEC), and solubility tests. At the optimum reaction conditions, the yield of oligo‐N,N′‐bis[(2‐hydroxy‐1‐naphthyl)methylene]urea (O‐2‐HNMU) was found to be 95% (for air O2 oxidant), 51% (for H2O2 oxidant), 96% (for NaOCl oxidant). According to the SEC analysis, the number‐average molecular weight (Mn), weight‐average molecular weight (Mw), and polydispersity index values of O‐2‐HNMU was found to be 1036, 1225 g/mol, and 1.182, respectively, using H2O2, and 765, 1080 g/mol, and 1.412, respectively, using air O2, and 857, 1105 g/mol, and 1.289, respectively, using NaOCl. TG‐DTA analyses showed that O‐2‐HNMU was more stable than 2‐HNMU. According to TG analyses, the carbonaceous residue of 2‐HNMU and O‐2‐HNMU was found to be 0.49% and 2.11% at 1000°C, respectively. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Modification of the physical, mechanical and thermal properties of poly(vinyl chloride) by blending with poly(ethyl methacrylate)
Authors: Chakrabarti Rupa , Chakraborty Debabrata
Published: April 2007

Blends of poly(vinyl chloride) (PVC) with different ratio of poly(ethyl methacrylate) were characterized with respect to their physical, mechanical, thermal, and morphological properties. The blends indicated a gradual rise in the modulus and ultimate tensile strength values followed by a reduction in the percent elongation at break and toughness values after an initial rise compared to the base reference compound PVC. The effect of composition of the PVC‐PEMA blends on the thermal stability was investigated. Differential scanning calorimetric curves of the blends showed an inward shift of the PVC glass transition temperature and an upward shift in the degradation temperature. The thermomechanical analysis results also indicated thermal stability over unmodified base reference compound PVC from the softening characteristics of the different samples under study. The biphasic cocontinuous systems as explicit from the scanning electron and optical micrographs supported phase‐mixing at the initial stages with subsequent phasing out tendency with increasing percentage of PEMA incorporation. The thermomechanical parameters are in conformity to their mechanicals, which have been further supported by their morphological studies. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Preparation and characterization of polystyrene modified single‐walled carbon nanotube
Authors: Guojian Wang , Yue Dong , Lin Liu , Caixia Zhao
Published: April 2007

A halogen atom terminated Polystyrene (PSt) was prepared by means of atom transfer radical polymerization. Then, the halogen atom was converted into ‐N3 group and a ‐N3 terminated PSt was obtained. Finally PSt was grafted onto the surface of single walled carbon nanotube (SWNT) by the reaction of azide group with SWNT. Comparison of X‐ray photoelectron spectrometer of N1s electron belonging to ‐N3 and the surface of SWNT demonstrated that three‐membered rings were formed by releasing N2 from ‐N3 during the reaction. The structure of PSt modified SWNT was characterized by FTIR, UV, Raman spectrum, and TEM. The experimental results showed that the PSt was connected assuredly to SWNT by the covalent bond. TGA data showed that the amount of PSt on the surface of SWNT firstly increased with growing
$ \overline{M}_n $
of PSt and then decrease when $ \overline{M}_n $
continues to grow. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Effect of soft segment composition on the physical properties of nonionic aqueous polyurethane containing side chain PEGME
Authors: Yen Meng‐Shung , Tsai Hsiang‐Chin , Hong Po‐Da
Published: April 2007

In this study, a series of nonionic waterborne polyurethanes containing side chain poly(ethylene glycol) monomethyl ether (PEGME) were synthesized using 4,4‐methylene bis(isocyanatocyclohexane), the nonionic dispersing center produced by isophorone diisocyanate, N‐diethanol amine, and PEGME, and a series of soft segments [polyethylene glycol (PEG), polypropylene glycol (PPG), polytetramethylene glycol (PTMG), and polycaprolactone (PCL)] with a different molecular weight. The solution properties of the polyurethane (PU) dispersions, thermal properties of the PU casting films, and the water vapor permeability (WVP) of the PU coated fabrics were investigated. Our results show that the surface tension of PU dispersion and its contact angle to untreated nylon fabric are higher for the ether‐based PU dispersion than for the ester‐based PU dispersion, with a sequence of PEG‐PU ≫ PTMG‐PU ≫ PPG‐PU ≫ PCL‐PU. Both the surface tension and the contact angle between PU dispersion and nylon fabric increase upon increasing the Mw of the soft segment. As for the thermal property of PU film, the Tgs of PCL‐PU is the highest, followed by PEG‐PU, PTMG‐PU, and PPG‐PU, and the Tgs decreases with the increase in the length of the soft segment. The Tms follows the order: PEG‐PU ≫ PCL‐PU ≫ PPG‐PU ≫ PTMG‐PU, and the Tms increases upon increasing the soft segment length. As regard to PU coated fabric, the trend of WVP is PEG‐PU ≫ PTMG‐PU ≫ PPG‐PU ≫ PCL‐PU, which increases with the increasing the soft segment length. With regarding to application for the coating, the Coated‐PU with PEG‐PU has an excellent WVP. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Properties of poly(urea‐formaldheyde) microcapsules containing an epoxy resin
Authors: Cosco S. , Ambrogi V. , Musto P. , Carfagna C.
Published: April 2007

Physical properties of urea‐formaldehyde microcapsules containing an epoxy resin are presented and discussed. Microcapsules were prepared by in situ polymerization of monomers in an oil‐in‐water emulsion. Differential scanning calorimetry, thermogravimetric analysis, and scanning electronic microscopy were applied to investigate thermal and morphological microcapsule properties. Microencapsulation was detected by means of FTIR and Raman techniques. It was found that the amount of encapsulated epoxy resin as well as the extent of urea‐formaldehyde polymerization depends on the reaction temperature and the stirring speed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Synthesis of SBR/PMMA core/shell latices: The role of initiator and surfactant on particle morphology and instability performance
Authors: Moghbeli M. R. , Mohammadi N. , Bagheri R.
Published: April 2007

Poly(butadiene‐stat‐styrene)/poly(methylmetacrylate), SBR/PMMA, structural latices were synthesized by using equal moles of different kinds of surfactants: anionic, nonionic, and anionic/nonionic mixture in a two‐stage emulsion polymerization. The results indicate that the application of anionic surfactants for the first stage, accompanying sodium persulfate initiator, KPS, for both stages led to core/shell and raspberry morphologies depended upon the hydrophilic lipophilic balance (HLB) of the surfactant. On the other hand, a core/shell structure was observed for structural latices which were synthesized via application of nonionic or anionic/nonionic mixed surfactants along with azobisisobutyronitrile, AIBN, and KPS as first and second‐stage initiators, respectively. The surface polarity and wettability of the seed particles and finally the tendency of the systems to gain the minimum surface free energy change are the basis for the observed morphologies. On the other hand, the stability of core/shell particles was investigated via incremental addition of an electrolyte, ammonium acetate, at temperature close to the glass transition of PMMA shell, 85°C. The particle size measurement on destabilized samples showed that the core/shell latex only stabilized by anionic surfactant was considerabely microagglomerated with increasing the electrolyte content. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Processing of mica/epoxy nanocomposites by ultrasound mixing
Authors: Boukerrou Amar , Duchet Jannick , Fellahi Said , Sautereau Henry
Published: April 2007

Rubbery mica/epoxy nanocomposites are synthetized by in situ polymerization, and their morphology, mechanical, and viscoelastic properties were investigated by wide angle X‐ray scattering (WAXS), transmission electron microscopy (TEM), tensile testing, and dynamic mechanical thermal analysis (DMTA). Ultrasonicator was used as a means of applying external shearing forces to disperse the silicate clay layers in the epoxy matrix. The first step of the nanocomposite preparation consisted of swelling the mica in a curing agent, i.e., aliphatic diamine based on polyoxypropylene backbone having a low viscosity for better diffusion into the intragalleries. Then, the epoxy prepolymer was added into the mixture. It was expected to have better dispersion and intercalation of the nanoclay in the matrix. The study showed that the organomodification of mica with octadecylammonium ions leads to an increase in the initial d‐spacing ([d001] peak) from 12.3 to 28.1 Å, determined by WAXS, indicating the occurrence of an intercalation. The addition of 5 per hundred resin (phr) of MICAC18 into the epoxy matrix resulted in finer dispersion as evidenced by both the disappearance of the diffraction peak in the WAXS pattern and TEM images. The mechanical and viscoelastic properties were improved for both MICA and MICAC18 nanocomposites, however, more pronounced for the modified ones. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Polymerization of methacryl and triethoxysilane functionalized stearate ester: Titanium dioxide composite films and their photocatalytic degradations
Authors: Eren Tarik , Neren Ökte A.
Published: April 2007

Stearoyl chloride was reacted with 3‐(acryloyloxy)‐2‐hydroxypropyl methacrylate (AHM). Then the resulting product (SAHM) was reacted with 3‐amino propyl ethoxysilane (APTES) by Michael addition on the acrylate. The product (SAHMA) is a specialized coupling agent containing an oleophilic 18 carbon alkyl chain, a radically polymerizable methacrylate and an alkoxysilane group capable of coupling to inorganic surfaces, analyzed by FT‐IR, NMR, and UV techniques. Photopolymerization and free radical homo and copolymerization of SAHMA with styrene were examined. SAHMA was coupled to powdered titanium dioxide (P25‐Degussa) and polymerized. TiO2 filled materials were analyzed by SEM, UV and TGA techniques. Glass transiton temperatures (Tg) of the polymers were determined by differential scanning calorimeter (DSC). Interfacial compatibility between SAHMA and TiO2 was demonstrated by FT‐IR spectroscopy. The photocatalytic degradation of the TiO2‐SAHMA polymer films was also investigated under medium pressure mercury lamp illumination in air. SAHMA based film containing 2 wt % TiO2 showed the highest degradation and the highest loss in weight. The weight of the polymer was reduced by 25% of its initial value after irradiation for 40 h. To examine the surface morphology of the irradiated polymer films, SEM analysis was carried out and cavities were detected around TiO2 particles. The photocatalytic and thermomechanical properties of SAHMA and styrene (STY) based copolymers were also investigated. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Synthesis of ethyl propionate catalyzed by poly(N‐AEAAm‐co‐AAc)‐cl‐MBAm hydrogel‐immobilized lipase ofBacillus coagulansMTCC‐6375
Authors: Kanwar Shamsher Singh , Kaushal Rajeev Kumar , Aggarwal Amit , Chauhan Sandeep , Chimni Swapandeep Singh , Chauhan Ghansham Singh
Published: April 2007

A purified alkaline thermotolerant bacterial lipase ofBacillus coagulansMTCC‐6375 was efficiently immobilized onto poly(N‐AEAAm‐co‐AAc‐cl‐MBAm)‐hydrogel at pH 8.5 and at temperature 55°C in 16 h. The hydrogel‐bound matrix possessed 1.04 U/g (matrix) lipase activity with a specific activity of 1.8 U/mg of protein. The immobilized lipase resulted in formation of 52.5 mMof ethyl propionate (52% conversion) at 55°C in 9 h inn‐nonane. Ethanol and propionic acid when used in a ratio of 300 : 100 mM, respectively, inn‐nonane along with 10 mg of hydrogel‐bound lipase resulted in optimal synthesis of ethyl propionate (82.5 mM). Addition of molecular sieves (3 Å, 0.7 g/reaction volume) further enhanced the conversion rate to 82.4% resulting in 83.5 mMof ethyl propionate. Incubation temperature below or above 55°C had a marked effect on the synthesis of ethyl propionate. However, esterification performed inn‐heptane at 65°C resulted in 87.5 mMof ethyl propionate with a conversation rate of 89.3%. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Ionic elastomer blends of zinc salts of maleated natural rubber and carboxylated nitrile rubber: Effect of grafted maleic anhydride
Authors: Lopattananon N. , Kraibut A. , Sangjan R. , Seadan M.
Published: April 2007

Zinc neutralized maleated natural rubbers (Zn‐MNR) were prepared by solution grafting and neutralization with zinc acetate in one‐step. It was later used for blending with carboxylated nitrile rubber (XNBR) in the composition of 50/50 parts by weight. The effect of grafted anhydride content (1.2, 1.6, 2.0, and 2.5% wt of NR) on the tensile properties of ionic rubber blends (Zn‐MNR/XNBR) was investigated. The tensile strength of the ionic blends was found to be greater than those of pure rubbers. The modulus, tensile, and tear strength of the blends dramatically increased with increasing levels of grafted anhydride. The ionic rubber blends also possessed superior physical properties compared to those of the corresponding nonionic rubber blends (MNR/XNBR). Dynamic mechanical thermal analysis and scanning electron microscopic studies were performed to verify the process of mixing. Fourier transform infrared spectroscopic studies were carried out to characterize the nature of specific intermolecular interactions between Zn‐MNR and XNBR chain segments. The results indicated that the ion‐ion (Zn+ ‐COO−) interactions between Zn‐MNR and XNBR are formed at the interface, which provides the mean of compatibilization in the ionic rubber blends. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Synthesis of lamellar isobutyl silicates and dispersion in polypropylene melts
Authors: Chastek Thuy T. , Que Emily L. , Jarzombeck Phil , Macosko Christopher W. , Stein Andreas
Published: April 2007

A new synthetic clay, iC4‐LMS, which is a lamellar mesostructured silicate with isobutyl groups covalently attached to silicate sheets, was synthesized with the goal to increase the compatibility of the inorganic sheets with polypropylene (PP) in a melt‐blending process. The lamellar morphology of iC4‐LMS was confirmed using X‐ray diffraction and transmission electron microscopy. Based on 29Si and 13C{1H} CP‐MAS NMR spectra, isobutyl functional groups were attached to at least 10 mol % of silicate tetrahedral sites in the inorganic layers. These surface groups mimic the subunits in the PP chains. Samples of iC4‐LMS were mixed with several organic solvents and sonicated. The solvent most like PP, tetramethylpentadecane, had the highest viscosity, forming a gel which indicates very good dispersion of the clay. However, when iC4‐LMS was melt‐blended with PP, it did not show significant increase in rheology. This modest effect on rheology may arise from fracture of iC4‐LMS layers as a result of the shear stresses during melt blending produced by the viscous PP. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Synergistic effect of photo and chemical treatment on the rate of biodegradation of low density polyethylene by Fusarium sp. AF4
Authors: Hasan Fariha , Shah Aamer Ali , Hameed Abdul , Ahmed Safia
Published: April 2007

This work was focused on the possibility of accelerating the biodegradation process of low density polyethylene (LDPE). Comparative studies, between the properties of untreated LDPE pieces and those exposed to UV irradiation and nitric acid plus microbial culture treatment, were performed. The LDPE pieces were irradiated by UV light (254 nm wavelength) for 250 h and incubated with nitric acid (99.0%) at 80°C for 6 days. These pretreated LDPE pieces were used as sole carbon source in mineral salt medium and inoculated with the Fusarium sp. AF4, isolated from soil. The efficiency of the LDPE degradation depended on the growth phase in pure cultivation of the fungus. The changes in the structural properties of LDPE film because of UV‐nitric acid and microbial treatment were determined by Fourier transform infrared spectroscopy (FTIR). It was observed that in case of UV and nitric acid treated LDPE, peaks appeared at 1710 cm−1 and 831, which were then reduced to 1708 cm−1 and 830 after microbial treatment, indicating breakdown of polymer chain. In this study, it was observed that a synergistic effect of UV‐nitric acid and microbial treatment induced oxidation reaction that enhanced and accelerated the biodegradability rate of LDPE pieces. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Vapor diffusion in porous/nonporous polymer coatings by dielectric sorption analysis
Authors: Giacomelli Penon M. , Picken S. J. , Wübbenhorst M. , van Turnhout J.
Published: April 2007

The sorption of water vapor in various organic coatings (polyimide, polyamide 6.6 (PA6.6), epoxy, polymethyl methacrylate, low density polyethylene) and filters (polyvinylidene fluoride, polytetra‐fluoro‐ethylene, porous polyethylene, nitro cellulose, cotton linter) has been investigated by a technique called Dielectric Sorption Analysis (DSA). The technique is based on high‐resolution time‐resolved, capacitance measurements performed during exposure of an organic coating to humidified nitrogen. The DSA technique could distinguish between all samples, and the diffusion coefficient and maximum sorption is calculated for all samples. A frequency sweep with a dielectric analyzer showed that in all cases the water has no interaction with the polymer films, except PA6.6. For PA6.6 it is assumed that electrode polarization takes place. For filters a frequency sweep showed in two cases electrode polarization (porous polyethylene, cotton linter), two cases no interaction (polytetra‐fluoro‐ethylene, nitro cellulose) and two cases an intermediate effect (polyvinylidene fluoride 0.22 μm, polyvinylidene fluoride 0.45 μm). The filters described a desorption profile, likely due to swelling of the filters that caused the vapor to be pressed out of the pores of the filters. Mass transport properties derived from complementary weight measurements on epoxy films were in good agreement with the DSA results. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Preparation of fructose‐mediated (polyethylene glycol/chitosan) membrane and adsorption of heavy metal ions
Authors: Wang Jian‐Wen , Kuo Yi‐Ming
Published: April 2007

Chitosan is an efficient metal chelater, but its practical use is limited due to the stability in acid solutions, adsorption capacities. In this study, we attempt to find a new pH‐dependent adsorbent based on fructose‐mediated chitosan/PEG membrane and examines several experimental parameters relative to their formation and characteristics. The membrane was characterized in terms of their fourier transforms infrared spectroscopy‐attenuated total reflectance (FTIR‐ATR) spectra, X‐ray diffraction (XRD) analysis, surface morphologies, tensile strength, mediating degree analysis, and swelling behavior at pH 3 and 6 medium. To estimate the potential of these membranes as a biosorbent, the capability and behavior for the adsorption of heavy metal ions were investigated using Lead ions as a model compound. FTIR‐ATR result showed that the Schiff's base reaction was favor formed in high pH condition. Swelling study showed that the swelling degree of homogeneous mediated membrane decreases as the pH of the final fructose‐mediated chitosan/PEG gel increase, which was demonstrated by mediating degree analysis. Low crystallinity of fructose‐mediated membranes is responsible for its sorption efficiency. With increasing the amount of fructose in the chitosan/PEG there is a proportionality of the adsorption capacity except that the high fructose content (10 wt %). The pH 6 treated 5 wt % fructose‐mediated membrane has a maximum sorption capacity to about 185 mg/g. The adsorption isotherms could be well fitted by the Langmuir equation. The results showed the potential applicability of fructose‐mediated chitosan/PEG membrane as a biosorbent for metal recovery. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
The anti‐static poly(ethylene terephthalate) nanocomposite fiber by in situ polymerization: The thermo‐mechanical and electrical properties
Authors: Chen Xiaolei , Li Chunzhong , Shao Wei , Du H. L. , Burnell‐Gray J. S.
Published: April 2007

Poly(ethylene phthalate) (PET)/nano‐antimony doped tin oxide (ATO) composites prepared via in situ polymerization were spun into fiber by the melt‐spinning process. ATO were in the form of loose agglomeration dispersing in the PET fibers and the sizes of loose agglomeration were smaller than 150 nm. Comparing with the neat PET, the tenacity of PET/ATO hybrid fibers was improved, and PET/ATO hybrid fibers had a lower elongation at break by adding nano‐ATO. The percolation threshold of PET/ATO hybrid fibers at room temperature was as low as 1.05 wt %, much lower than that of the composites filled with conventional conductive particles. The PET/ATO hybrid fiber exhibited volume resistivity of 4.9 × 108 Ω cm when the contents of ATO were 1 wt %. The ATO nanoparticles improved the thermal stability of PET fiber. The WAXD and DSC results suggested that ATO nanoparticles increase the degree of crystallinity of PET acting as the nucleating agent, which prohibited the thermal shrinkage of PET fiber. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Preparation of porous PVDF membrane via thermally induced phase separation with diluent mixture of DBP and DEHP
Authors: Ji Gen‐Liang , Du Chun‐Hui , Zhu Bao‐Ku , Xu You‐Yi
Published: April 2007

Poly(vinylidene fluoride) microporous membranes were prepared via the thermally induced phase separation process using diluent mixture of dibutyl phthalate (DBP) and di(2‐ehylhexyl) phthalate (DEHP). The effects of the DBP ratio to DEHP in the diluent mixture on the phase diagrams were investigated. The phase diagrams can be controlled successfully by varying the DBP ratio in the diluent mixture. The compatibility between polymer and diluent mixture was characterized to explain the features in the phase diagram. The cross‐sectional structures of membranes were investigated and related to the DBP ratio in diluent mixtures, initial polymer concentration, and cooling rate. When the DBP ratio to DEHP was 30 wt/70 wt, only spherulites structure was obtained at the polymer concentration of 30 wt % and at the cooling rate of 10°C/min, whereas the cellular structure was detected as the polymer concentration increased or the cooling rate deceased. In the case of the systems with only S‐L phase separation, only spherulites structures were observed and the sizes of spherulites increased with increase in the polymer concentration and with decrease in the cooling rate. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Preparation of superhydrophobic silica‐based films by using polyethylene glycol and tetraethoxysilane
Authors: Chang Kuei‐Chien , Chen Yu‐Kai , Chen Hui
Published: April 2007

Preparation of superhydrophobic silica‐based films via sol‐gel process by adding polyethylene glycol (PEG4000) in the silica sol precursor solution has been developed. The casting films were prepared by casting the above solution on the glass and adding poor solvent on it or not. Surface roughness of the films was obtained by removing polymer from the films at high temperature. Then, the hydrophobic group on the surfaces was obtained by reaction with hexamethyldisilazane (HMDS). Characteristic properties of the as‐prepared surface of the films were analyzed by contact angle measurement, scanning electron microscopy (SEM), atomic force microscope (AFM), Fourier transform infrared (FT‐IR) spectrophotometer, and X‐ray photoelectron spectrometer (XPS). The results showed that the contact angles of the films were varied with the PEG weight fraction of the films, the solvent for the PEG solution, the reaction temperature and time, and adding poor solvent (n‐hexane) or not. However, the surface roughness has been controlled by adjusting the experimental parameters during the early period. The contact angle of the film that prepared by spraying the poor solvent (n‐hexane) onto each coating layer for four times after casting process was greater than 150°. It was difficult to obtain superhydrophobic surface without adding n‐hexane onto any coating layer in this system. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Crystallization behavior and mechanical properties of bio‐based green composites based on poly(L‐lactide) and kenaf fiber
Authors: Pan Pengju , Zhu Bo , Kai Weihua , Serizawa Shin , Iji Masatoshi , Inoue Yoshio
Published: April 2007

Bio‐based polymer composite was successfully fabricated from plant‐derived kenaf fiber (KF) and renewable resource‐based biodegradable polyester, poly(L‐lactide) (PLLA), by melt‐mixing technique. The effect of the KF weight contents (0, 10, 20, and 30 wt %) on crystallization behavior, composite morphology, mechanical, and dynamic mechanical properties of PLLA/KF composites were investigated. It was found that the incorporation of KF significantly improves the crystallization rate and tensile and storage modulus. The crystallization of PLLA can be completed during the cooling process from the melt at 5°C/min with the addition of 10 wt % KF. It was also observed that the nucleation density increases dramatically and the spherulite size drops greatly in the isothermal crystallization with the presence of KF. In addition, with the incorporation of 30 wt % KF, the half times of isothermal crystallization at 120°C and 140°C were reduced to 46.5% and 28.1% of the pure PLLA, respectively. Moreover, the tensile and storage modulus of the composite are improved by 30% and 28%, respectively, by the reinforcement with 30% KF. Scanning electron microscopy observation also showed that the crystallization rate and mechanical properties could be further improved by optimizing the interfacial interaction and compatibility between the KF and PLLA matrix. Overall, it was concluded that the KF could be the potential and promising filler for PLLA to produce biodegradable composite materials, owing to its good ability to improve the mechanical properties as well as to accelerate the crystallization of PLLA. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Multiple publication on a single research study: Does it pay? The influence of number of research articles on total citation counts in biomedicine
Authors: Bornmann Lutz , Daniel Hans‐Dieter
Published: April 2007

Scientists may seek to report a single definable body of research in more than one publication, that is, in repeated reports of the same work or in fractional reports, in order to disseminate their research as widely as possible in the scientific community. Up to now, however, it has not been examined whether this strategy of “multiple publication” in fact leads to greater reception of the research. In the present study, we investigate the influence of number of articles reporting the results of a single study on reception in the scientific community (total citation counts of an article on a single study). Our data set consists of 96 applicants for a research fellowship from the Boehringer Ingelheim Fonds (BIF), an international foundation for the promotion of basic research in biomedicine. The applicants reported to us all articles that they had published within the framework of their doctoral research projects. On this single project, the applicants had published from 1 to 16 articles (M = 4; Mdn = 3). The results of a regression model with an interaction term show that the practice of multiple publication of research study results does in fact lead to greater reception of the research (higher total citation counts) in the scientific community. However, reception is dependent upon length of article: the longer the article, the more total citation counts increase with the number of articles. Thus, it pays for scientists to practice multiple publication of study results in the form of sizable reports.
A model for quantitative evaluation of an end‐to‐end question‐answering system
Authors: Wacholder Nina , Kelly Diane , Kantor Paul , Rittman Robert , Sun Ying , Bai Bing , Small Sharon , Yamrom Boris , Strzalkowski Tomek
Published: April 2007

We describe a procedure for quantitative evaluation of interactive question‐answering systems and illustrate it with application to the High‐Quality Interactive Question‐Answering (HITIQA) system. Our objectives were (a) to design a method to realistically and reliably assess interactive question‐answering systems by comparing the quality of reports produced using different systems, (b) to conduct a pilot test of this method, and (c) to perform a formative evaluation of the HITIQA system. Far more important than the specific information gathered from this pilot evaluation is the development of (a) a protocol for evaluating an emerging technology, (b) reusable assessment instruments, and (c) the knowledge gained in conducting the evaluation. We conclude that this method, which uses a surprisingly small number of subjects and does not rely on predetermined relevance judgments, measures the impact of system change on work produced by users. Therefore this method can be used to compare the product of interactive systems that use different underlying technologies.
Exploiting parallelism to support scalable hierarchical clustering
Authors: Cathey Rebecca J. , Jensen Eric C. , Beitzel Steven M. , Frieder Ophir , Grossman David
Published: April 2007

A distributed memory parallel version of the group average hierarchical agglomerative clustering algorithm is proposed to enable scaling the document clustering problem to large collections. Using standard message passing operations reduces interprocess communication while maintaining efficient load balancing. In a series of experiments using a subset of a standard Text REtrieval Conference (TREC) test collection, our parallel hierarchical clustering algorithm is shown to be scalable in terms of processors efficiently used and the collection size. Results show that our algorithm performs close to the expectedO(n2/p) time onpprocessors rather than the worst‐caseO(n3/p) time. Furthermore, theO(n2/p) memory complexity per node allows larger collections to be clustered as the number of nodes increases. While partitioning algorithms such ask‐means are trivially parallelizable, our results confirm those of other studies which showed that hierarchical algorithms produce significantly tighter clusters in the document clustering task. Finally, we show how our parallel hierarchical agglomerative clustering algorithm can be used as the clustering subroutine for a parallel version of the buckshot algorithm to cluster the complete TREC collection at near theoretical runtime expectations.
AxBAx‐Type Block–Graft Polymers with Soft Methacrylate Middle Segments and Hard Styrene Outer Grafts: Synthesis, Morphology, and Mechanical Properties
Authors: Miura Yu , Kaneko Takeshi , Satoh Kotaro , Kamigaito Masami , Jinnai Hiroshi , Okamoto Yoshio
Published: April 2007

Novel copolymers with controlled architectures can function as new building blocks for well‐defined nanostructures on the basis of microphase separation, unlike conventional ABA triblock copolymers. A series of well‐defined AxBAx‐type block–graft copolymers consisting of soft middle segments (dodecyl methacrylate (DMA)) and hard outer graft chains (styrene (St)) were synthesized by ruthenium‐catalyzed living radical block and graft polymerization. NMR spectroscopy and size‐exclusion chromatography combined with multiangle laser light scattering confirmed the well‐defined structure of the AxBAx block–graft copolymers with backbones and graft chains of controlled lengths. Transmission electron microscopy and transmission electron microtomography revealed a series of morphologies for the copolymers. Morphological changes were observed from PSt “honeycomb” cylinders to lamellae and poly(DMA) cylinders with increasing PSt‐graft content, whereby the phase diagram was shifted significantly to lower volume fractions of the larger‐number component (St) relative to those of the corresponding ABA triblock copolymers. More specifically, poly(DMA) cylinders were observed even before the St content reached 50 wt %. The AxBAx and ABA copolymers with 17–30 wt % of St exhibited characteristics of a thermoplastic elastomer with tensile strengths of 1–6 MPa and elongations at break of 70–300 %. These mechanical properties can be related well to the microphase structures of the AxBAx and ABA copolymers.
Role of the Preparation Procedure in the Formation of Spherical and Monodisperse Surfactant/Polyelectrolyte Complexes
Authors: Luan Yuxia , Ramos Laurence
Published: April 2007

Complexes formed by a double‐tail cationic surfactant, didodecyldimethyl ammonium bromide, and an anionic polyelectrolyte, an alternating copolymer of poly(styrene‐alt‐maleic acid) in its sodium salt form, were investigated with respect to variation in the charge ratio (x) between the polyelectrolyte negative charges and the surfactant positive charges. The morphology and microstructure of the complexes were studied by light microscopy and small‐angle X‐ray scattering for different preparation conditions. Independent of the sample preparation procedure and the charge ratio x, the X‐ray results show that the microscopic structure of the complexes is a condensed lamellar phase. By contrast, the morphology of the complexes changes dramatically with the preparation procedure. The complexes formed by mixing a surfactant solution and a polyelectrolyte solution strongly depend on x and are always extremely heterogeneous in size and shape. Surprisingly, we show that, when the two solutions interdiffuse slowly, spherical complexes of micrometric and rather uniform size are systematically obtained, independently on the initial relative amount of surfactant and polyelectrolyte. The mechanism for the formation of these peculiar complexes is discussed.