bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation and characterization of transparent PANI‐SIO2 hybrid conducting films
Authors: Wei Li , Chen Qi , Gu Yingjun 
Published: December 2009

AbstractDodecylbenzene sulfonic acid‐doped polyaniline (DBSA‐PANI) was prepared with 3‐glycidoxypropyltrimethoxysilane (GPTMS) through a sol–gel route without water and ethanol. Acetic acid was used to play both the roles of reagent and catalyst during the hydrolysis‐condensation reaction of GPTMS, which affected the structure of precursors. On the other hand, m‐cresol can adjust the acidity of solution and it was also a secondary dopant in DBSA‐PANI to enhance conductivity of hybrid films. The conductivity and visible light transmittance vary with the molar ratio of acetic acid to GPTMS and m‐cresol to GPTMS. Sheet resistance of the new hybrid films made by a dipping process reaches 5.1 kΩ/□ and visible light transmittance is higher than 75%. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers
Rheology and extrusion foaming of chain‐branched poly(lactic acid)
Authors: Mihai Mihaela , Huneault Michel A. , Favis Basil D. 
Published: December 2009

AbstractIn this study, the effect of macromolecular chain‐branching on poly(lactic acid) (PLA) rheology, crystallization, and extrusion foaming was investigated. Two PLA grades, an amorphous and a semi‐crystalline one, were branched using a multifunctional styrene‐acrylic‐epoxy copolymer. The branching of PLA and its foaming were achieved in one‐step extrusion process. Carbon dioxide (CO2), in concentration up to 9%, was used as expansion agent to obtain foams from the two PLA branched using chain‐extender contents up to 2%. The foams were investigated with respect to their shear and elongational behavior, crystallinity, morphology, and density. The addition of the chain‐extender led to an increase in complex viscosity, elasticity, elongational viscosity, and in the manifestation of the strain‐hardening phenomena. Low‐density foams were obtained at 5–9% CO2for semi‐crystalline PLA and only at 9% CO2in the case of the amorphous PLA. Differences in foaming behavior were attributed to crystallites formation during the foaming process. The rheological and structural changes associated with PLA chain‐extension lowered the achieved crystallinity but slightly improved the foamability at low CO2content. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers
Synthesis and characterization of poly(butyl acrylate‐co‐ethylhexyl acrylate)/ poly(vinyl chloride)[P(BA‐EHA)/PVC] novel core‐shell modifier and its impact modification for a poly(vinyl chloride)‐based blend
Authors: Pan Mingwang , Xing Shengnan , Yuan Jinfeng , Wu Jiawei , Zhang Liucheng 
Published: December 2009

AbstractSynthesis of poly(butyl acrylate‐co‐ethylhexyl acrylate)‐core/poly(vinyl chloride)‐shell [P(BA‐EHA)/PVC] used as a modifying agent of PVC via semicontinuous seeded emulsion copolymerization is reported here. Diameter distributions and morphology of the composite latex particles were characterized with the aid of particle size analyzer and transmission electron microscopy (TEM). The grafting efficiency (GE) and grafting ratio (GR) of vinyl chloride (VC) grafted onto the P(BA‐EHA) with varying content of crosslinking agent and core‐shell ratios were investigated. TEM studies indicated that the P(BA‐EHA)/PVC latex particles have core‐shell structure, and the P(BA‐EHA) rubbery particles in blending materials were uniformly dispersed in PVC matrix. Dynamic mechanical analysis (DMA) results revealed that the compatibility between the P(BA‐EHA) and the PVC matrix was significantly improved due to the presence of the P(BA‐EHA)‐grafted‐VC copolymer. The notched impact strength of the blending material with 3 wt% of rubber content was seven times that of the PVC. Linear regressions of mechanical properties as loading of the modifier were made. The resulting data of notched impact strength and elongation at break for the blending materials deviated significantly from regression lines within 3–4.5 wt% of the P(BA‐EHA) content. The PVC blends modified by the modifier exhibited good toughness and easy processability. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers
Effect of relatively nontoxic thermal stabilizers on photodegradation of poly(vinyl chloride)
Authors: Xiang Xiuqin , Chen Shuangjun , Zhang Jun , Huang Xin 
Published: December 2009

AbstractThe influence of relatively nontoxic thermal stabilizers including different types of organic calcium complex (Ca/Zn system of liquid stabilizers) and organotin on photodegradation of poly(vinyl chloride) (PVC) was investigated by color difference measurement, viscosity‐average molecular weight determination, UV–vis spectroscopy, Fourier transform infrared (FTIR), and thermogravimetric (TG) analysis. PVC films containing relatively nontoxic thermal stabilizers were prepared by solution casting and then exposed to xenon‐arc light source with the irradiance of 0.51 W/(m2·nm) at 65°C. Two major chain processes, photodehydrochlorination and photo‐oxidation, occur simultaneously during photodegradation of PVC. It has been confirmed by both color difference and UV–vis spectra that during the former 300 h of irradiation, organic calcium complex stabilizers retard photodehydrochlorination as well as initial color development of PVC films while organotin stabilizers remarkably accelerate photodehydrochlorination after 100 h. Relative carbonyl index (RCI) is first introduced to the analysis of FTIR results, which implies that organotin has a better ability to inhibit photo‐oxidation than organic calcium complex and ensures longer stabilization time. The antioxidation of mercaptan organotin has been observed because it is an effective decomposer of peroxides and hydroperoxides. TG analysis reveals that some unstable structures generated due to the irradiation of ultraviolet can easily split away off from PVC macromolecular backbones under relatively low temperature. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers
Ionic liquids as plasticizers/lubricants for polylactic acid
Authors: Park Kuil , Ha Jin Uk , Xanthos Marino 
Published: December 2009

AbstractIn this study, two ionic liquids (IL) with different anions (decanoate, tetrafluoroborate) but with the same phosphonium‐based cation were evaluated as potential plasticizers and lubricants for polylactic acid (PLA). Both ILs at 5 wt% were well dispersible and partly miscible with PLA as evidenced by scanning electron microscopy, SEM, and glass transition temperature, Tg, characterization, as well as from solubility parameters calculations. However, phase separation in the PLA system containing the IL with tetrafluoroborate anions was observed 1 year after melt processing. The IL containing the tetrafluoroborate anion showed higher thermal stability compared with the IL containing decanoate as confirmed by thermogravimetric analysis. This was translated in corresponding behaviors of the PLA blends. The effects of the IL containing the tetrafluoroborate anion were more pronounced on lubrication as evidenced by lower values of coefficient of friction that could also be correlated with lower contact angle; this IL could then be considered as a more effective, overall, plasticizer than the IL containing the decanoate anion based on reduced flexural modulus and brittleness as well as Tg suppression results. The extent of plasticization, however, could also be related to the molecular weight reduction during melt processing that occurred in the presence of both ILs, but to different degrees. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers
Adhesion and delamination failure mechanisms in alternating layered polyamide and polyethylene with compatibilizer
Authors: Du Qin , Jiang Genjie , Li Jiang , Guo Shaoyun 
Published: December 2009

AbstractThe effects of compatibilizer and the number of layers on the interfacial adhesion and delamination model of coextruded microlayer samples consisting of alternating layers of high‐density polyethylene (HDPE) and polyamide 6 (PA6) were studied with T‐peel test. When more maleic anhydride‐grafted HDPE was incorporated into HDPE layer, the interfacial delamination model changed from adhesive to cohesive failure in the case of bilayer samples. For high‐layer samples, the results of X‐ray photoelectron spectroscopy showed that the areal density of copolymers at the interfaces increased with increasing number of layers due to strong and durable shearing forces during microlayer coextrusion. Scanning electron microscopy observation revealed that the interfacial delamination model changed from single‐ to multiple‐interface delamination when the number of layers increased from 16 to 32. The crack propagation included a large number of layer–layer jumps. The peel strength of microlayer samples was found to be greatly influenced by the interfacial delamination mechanisms. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers
Operating window for the peeling of polyimide film
Authors: Wang Han‐Yi , Liu Ta‐Jo , Liu Shur‐Fen , Jeng Jhy‐Long 
Published: December 2009

AbstractThe peeling behavior of polyimide film coated on steel substrates was experimentally investigated and compared with existing models. An operating window for peeling, which is defined as a closed domain for steady and defect‐free peeling, is presented in terms of peeling force versus residual solvent content. The window is bounded by two major defects: the film becomes too brittle for peeling at high peeling force, and stick‐slip striation defect appears at low peeling force. There exists a critical residual solvent content below which the adhesion between the polyimide film and the substrate is too strong and then peeling is impossible. Existing models for predicting steady peeling and the onset of peeling defects have been modified and applied to setup the boundaries of the operating window. There also exists another operating window for drying of polyimide and is presented in the form of drying temperature versus film thickness. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers
Real‐time ultrasonic characterization of the chain orientation of high density polyethylene melts during processing
Authors: Lin Congmei , Wang Shan , Sun Huimin , Li Jiang , Guo Shaoyun 
Published: December 2009

AbstractIn an attempt to understand the relationships between the evolution of ultrasonic signal and the change of molecular structure during processing, shear‐induced chain orientation and its subsequent disorientation of high‐density polyethylene (HDPE) melts with different melt indices were studied using a noninvasive and nondestructive ultrasonic technique. The molecular structural development during orientation and disorientation of these melts was manifested in the ultrasonic velocity. Two models were developed to describe the relaxation processes of orientation and disorientation, respectively. The effects of shear rate and temperature on the maximal degree of orientation and the relaxation time of orientation and disorientation were also explored. These results from the ultrasonic measurements were compared with ones obtained through rheological measurements, X‐ray diffraction (XRD), and infrared dichroism measurements. The experimental results indicated that the ultrasonic technique was sensitive and promising for the real‐time monitoring of the evolution of molecular structure during polymer processing. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers
The processing of polypropylene cast films. I. Impact of material properties and processing conditions on film formation
Authors: Aniunoh Kenneth , Harrison Graham M. 
Published: December 2009

AbstractMaterial properties have a significant impact on the response of polymers to industrial flow processes such as film casting. During film casting, molten polymer is extruded through an (approximately) rectangular die and then cooled rapidly. Subsequent biaxial stretching can be employed to manipulate the film properties. In this work, we investigate the effect of polymer viscosity (molecular weight), draw ratio, and die temperature on polypropylene film formation. We measure the width, two components of the velocity vector, and the temperature profiles throughout the film web. The polymer rheology and the die temperature affect the film geometry and temperature profiles in the air‐gap. The magnitude of the machine direction velocity component depends on both the machine and transverse position in the film. The velocity shows a maximum at the centerline and decreases toward the film edge. The measured transverse velocity component, a consequence of the film neck‐in, is seen to decrease from the film edges to the centerline. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers
Formation and characterization of polyethylene blends for autoclave‐based expanded‐bead foams
Authors: Behravesh Amir H. , Park Chul B. , Lee Eung K. 
Published: December 2009

AbstractBlends of linear‐low‐density polyethylene (LLDPE), low‐density polyethylene (LDPE), and high‐ density polyethylene (HDPE) were foamed and characterized in this research. The goal was to generate clear dual peaks from the expanded polyethylene (EPE) foam beads made from these blends in autoclave processing. Three blends were prepared in a twin‐screw mixing extruder at two rotational speeds of 5 and 50 rpm: Blend1 (LLDPE with 20 wt% HDPE), Blend 2 (LLDPE with 20 wt% LDPE), and Blend 3 (LLDPE with 10 wt% HDPE and 10 wt% LDPE). The differential scanning calorimetric (DSC) measurement was taken at two cooling rates: 5 and 50°C/min. Although no dual peaks were present, the results showed that blending with HDPE has a more noticeable effect on the DSC curve of LLDPE than blending with LDPE. Also, the rotational speed and cooling rate affected the shape of the DSC curves and the percentage area below the onset point. The DSC characterization of the batch foamed blends revealed multiple peaks at certain temperatures, which may be mainly due to the annealing effect during the gas saturation process. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers
Model identification of a twin screw extruder for thermoplastic vulcanizate (TPV) applications
Authors: Trifkovic M. , Sheikhzadeh M. , Choo K. , Rohani S. 
Published: December 2009

AbstractMulti‐input multi‐output (MIMO) models of a twin‐screw co‐rotating extruder for thermoplastic vulcanizate (TPV) are developed using the process identification techniques. The process inputs are screw speed (SS) and barrel temperature (WT). The three outputs are motor load (ML), melt temperature (MT), and melt pressure (MP). Two appropriate rubbers for TPV applications with different physical and mechanical properties are used for the experimentation. The process model is obtained from the experimental input–output data using various identification techniques such as least squares and prediction error. Recursive online model identification is performed on the process to update the model parameters in real time. To perform the identification studies, the process data was transferred via OPC server from the local PLC (Programmable Logic Controller) to the Advanced Control and Identification toolbox in MATLAB software. The effect of rubber properties and two curative agents (Peroxide and Phenolic) in the TPV experiment are studied on the final identified models. This comprehensive model identification study provided sufficient accurate models for further model based process analysis and control for TPV applications. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers
BIPV: merging the photovoltaic with the construction industry
Authors: Pagliaro Mario , Ciriminna Rosaria , Palmisano Giovanni 
Published: December 2009

AbstractBIPV (Building Integrated Photovoltaics) is a multifunctional technology that unifies the photovoltaic module with the overall building outer surface providing the building with several new functions while producing a portion or total building electricity usage. Increasing the aesthetic, functional and environmental value of a building at a much lower cost than in the recent past, new PV technologies will soon originate a market growth as intense as the growth of traditional PV market has been in the last 5 years. Copyright © 2009 John Wiley & Sons, Ltd.magnified image
Separation of local bulk and surface recombination in crystalline silicon from luminescence reabsorption
Authors: Giesecke J. A. , Kasemann M. , Schubert M. C. , Würfel P. , Warta W. 
Published: December 2009

AbstractSpontaneous photoemission of crystalline silicon provides information on excess charge carrier density and thereby on electronic properties such as charge carrier recombination lifetime and series resistance. This paper is dedicated to separating bulk recombination from surface recombination in silicon solar cells and wafers by exploiting reabsorption of spontaneously emitted photons. The approach is based on a comparison between luminescence images acquired with different optical short pass filters and a comprehensive mathematical model. An algorithm to separate both front and back surface recombination velocities and minority carrier diffusion length from photoluminescence (PL) images on silicon wafers is introduced. This algorithm can likewise be used to simultaneously determine back surface recombination velocity and minority carrier diffusion length in the base of a standard crystalline silicon solar cell from electroluminescence (EL) images. The proposed method is successfully tested experimentally. Copyright © 2009 John Wiley & Sons, Ltd.
Screen printing metallization of boron emitters
Authors: Lago R. , Pérez L. , Kerp H. , Freire I. , Hoces I. , Azkona N. , Recart F. , Jimeno J. C. 
Published: December 2009

AbstractThis paper analyzes the influence of the composition of screen printing metal pastes on contacting boron emitters for crystalline silicon solar cells, optimized on the basis of commercial Ag‐paste Ferro 3347 by adding silicon and aluminum. Aluminum provides a lower contact resistance, while silicon prevents the spiking and alloying of aluminum with the silicon of the substrate. The best pastes have turned out to be high Si‐concentrated, which have provided a final specific contact resistance of 3–4 mΩ cm2on screen printed boron emitters diffused at 1000°C for 8 min, with shunt conductance lower than 0.6 mS/cm2. The final fill factors have been better than 77.5% and open circuit voltages have exceeded 605 mV on Czochralski (Cz)ntype 0.7 Ω cm solar cells. These results have proven the feasibility of our screen printing process forp+nn+structures. Copyright © 2009 John Wiley & Sons, Ltd.
Non‐Destructive Sub‐Surface Chemical Characterization of Air‐Exposed Plasma Polymers by Energy‐Resolved XPS
Authors: Girard‐Lauriault Pierre‐Luc , Retzko Iris , Swaraj Sufal , Matsubayashi Nobuyuki , Gross Thomas , Mix Renate , Unger Wolfgang E. S. 
Published: December 2009

AbstractPlasma polymers containing oxygen‐ and nitrogen‐based surface chemistries were prepared from allyl alcohol, allylamine and acrylic acid. Established selective chemical derivatisation procedures with trifluoroacetic anhydride (TFAA) and 4‐trifluoromethyl benzaldehyde (TFBA) were used to determine alcohols and amines, respectively. Samples were analysed by energy‐resolved XPS (ERXPS), enabling XPS depth resolution. We demonstrated that slightly aged plasma polymers prepared from allyl alcohol and allylamine present a homogeneous sub‐surface chemistry within the range of the XPS information depth (≈10 nm); this was clearly not the case for their acrylic acid counterparts. Furthermore, it is shown that standard derivatisation reactions result in homogeneous changes of the chemistry.magnified image
Characterization of spin crossover crystal surface by AFM
Authors: Chong C. , Berini B. , Boukheddaden K. , Codjovi E. , Linarès J. , Garcia Y. , Naik A. D. , Varret F. 
Published: December 2009

AbstractImaging nano‐domains in spin crossover (SCO) compounds remains so far an unreached goal. We report on the first AFM tapping‐mode investigation of SCO single crystals, performed at room temperature with the well known mononuclear compound [Fe(ptz)6](BF4)2 (ptz = 1‐propyl‐tetrazole) and the trinuclear supramolecular compound [Fe3(hyetrz)6(H2O)6](CF3SO3)6 (hyetrz = 4‐(2′‐hydroxyethyl)‐1,2,4‐triazole) which shows a gradual spin conversion centred at room temperature. The natural surface of the former crystal revealed a volatile coating of the scanned area attributed to the transport of adsorbed water under the effect of interaction with the AFM tip. The second one showed astonishing leopard‐skin patterns assigned to the effect of atmospheric humidity on this hygroscopic compound. Their origin is discussed. We suggest the use of fluid coating layers as a general method for revealing the nano‐patterning of physical properties (e.g. like‐spin domains) at the surface of dielectric materials.AFM‐tapping images of [Fe3(hyetrz)6(H2O)6](CF3SO3)6 at room temperature and ambient atmosphere.magnified image
Electronic ferroelectricity, charge ordering and structural phase transitions in LuFe2O4(LuFeO3)n (n = 0 and 1)
Authors: Yang Huaixin , Zhang Ying , Qin Yuanbin , Ma Chao , Tian Huanfan , Li Jianqi 
Published: December 2009

AbstractThe nature of the charge order, multiferroic features, and structural phase transitions in LuFe2O4(LuFeO3)n (n = 0 and 1) materials have been extensively investigated. In situ transmission electron microscopy (TEM) investigations on LuFe2O4 (n = 0) show the presence of well‐defined charge‐ordered states at low temperatures that could give rise to a notable ferroelectric polarization. Measurements of the structural and physical properties on LuFe2O4(LuFeO3)n (n = 1) demonstrate that the intercalation of the LuFeO3‐block could lead to visible changes in the dielectric properties and the charge ordering (CO) features. Measurements of ferroelectric properties suggest that Mn substitution for Fe in Lu2Fe2Fe1–xMnxO7 (0 < x ≤ 0.86) can notably suppress the conducting leakage current and results in clear hysteresis loops in the polarization–electric field switching curves.
Investigation of graphene–SiC interface by nanoscale electrical characterization
Authors: Sonde Sushant , Giannazzo Filippo , Raineri Vito , Rimini Emanuele 
Published: December 2009

AbstractWe have carried out an investigation of graphene/4H‐SiC (0001) interface by nanoscale current transport measurements. Graphene was deposited by mechanical exfoliation of HOPG. Novel Scanning Probe Current Mapping and Scanning Probe Current Spectroscopy are found to be useful for non‐destructive characterization of graphene. Presence of graphene lowers Schottky barrier height on 4H‐SiC (0001). Observed barrier heights (0.8 ± 0.1 eV) are comparable but higher than reported in literature for 6H‐SiC (0001). Current mapping of graphene deposited on 4H‐SIC(0001). Highly conductive regions in the current maps correspond to graphene in the morphological maps.
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Structure and stability of cub‐Pr2O3 films on Si(111) under post deposition annealing conditions
Authors: Gevers S. , Weisemoeller T. , Zimmermann B. , Deiter C. , Wollschläger J. 
Published: December 2009

AbstractUltra thin heteroepitaxial Pr2O3 films on Si(111) were characterized by X‐ray diffraction and X‐ray reflectometry to determine the film and interface structure. These results exhibit two oxide phases within the praseodymia film after preparation which can be assigned to different oxygen stoichiometries. After post deposition annealing of the films at different temperatures up to 600 °C the surface was studied by spot profile analysis low energy electron diffraction, with regard to the stability of the film surface.The results show that terraces with mono‐atomic step heights and mosaics can be found at the film surfaces after annealing at 300 °C. Higher annealing temperatures do not cause further changes of structure and morphology except of a slight increase of the mosaic spread due to lateral strain effects within the oxide film. These results indicate that the films are stable at temperatures as high as 600 °C. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)