bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

AbstractStearoyl 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

AbstractA 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

AbstractZinc 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

AbstractA 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

AbstractThis 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

AbstractThe 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

AbstractChitosan 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

AbstractPoly(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

AbstractPoly(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

AbstractPreparation 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

AbstractBio‐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

AbstractScientists 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

AbstractWe 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

AbstractA 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

AbstractNovel 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.