bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermal properties and flame‐retardancy of ethylene‐octene copolymer/organ‐montmorillonite nanocomposites
Authors: Qin Shuhao , Li Qingfeng , Yu Jie , Wei Liangqing , Guo Jianbing , Shao Huiju , Liang Shan , Luo Zhu 
Published: May 2012

AbstractTwo series of thermoplastic elastomer ethylene‐octene copolymer (POE) composites and maleated ethylene‐octene (POE‐g‐MAH) with organo‐montmorillonite (OMMT) were prepared via melting processing to study their thermal properties and flame‐retardancy. The morphology was studied by transmission electron microscope (TEM). The influence of clay dispersion on thermal and flammability properties was investigated by using thermal gravimetric analysis (TGA) and cone calorimeter. TEM showed that agglomerated structure of OMMT within POE matrix but intercalated/exfoliated structures throughout POE‐g‐MAH matrix. The different dispersion of OMMT resulted in more significant improvements on thermal stability and flame‐retardancy in the POE‐g‐MAH/OMMT nanocomposites compared with POE/OMMT microcomposites. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Thermal and rheological effects of sepiolite in linear low‐density polyethylene/starch blend
Authors: Mir Sadullah , Yasin Tariq , Halley Peter J. , Siddiqi Humaira Masood , Ozdemir Orhan , Nguyen Anh 
Published: May 2012

AbstractEffect of different concentrations of sepiolite on thermal and rheological properties of linear low‐density polyethylene/starch blend was investigated. Vinyl trimethoxy silane was used as compatibilizing and crosslinking agent. The composites were produced by peroxide‐initiated melt mixing technique. Improved thermal stability and tensile strength were observed in crosslinked formulations. Maximum tensile properties were observed in composites containing 2 parts per hundred (phr) sepiolite and 15 phr starch. Rheological study of crosslinked composite showed a linear viscoelastic behavior with high complex viscosity and dynamic shear storage modulus. Scanning electron microscopy also revealed that silane has improved the dispersion of filler and interaction among the polymer and filler interphase. These results suggest that the presence of sepiolite act as an effective filler to enhance the thermal and rheological properties. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci, 2013
Experimental and modeling study of the solid state polymerization of poly(ethylene terephthalate) over a wide range of temperatures and particle sizes
Authors: Zhang Jun , Shen Xi‐Jun , Zhang Jian , Feng Lian‐Fang , Wang Jia‐Jun 
Published: May 2012

AbstractThe solid state polymerization (SSP) of poly(ethylene terephthalate) was studied experimentally over a wide range of pellet sizes and temperatures. A comprehensive model was developed. It considered polycondensation, degradation and polycondensation of vinyl end groups together with diffusion. The reaction rate constants, diffusivities and the corresponding activation energies were obtained through parameter identification using experimental data. The effects of the reaction temperature and pellet size on the SSP time were also investigated. A decrease in the particle size decreases the concentration of the vinyl end groups and narrows the concentration distribution of end groups inside poly(ethylene terephthalate) particles. A decrease in the size of pellets also favors diffusion. Nevertheless it is preferable that the size of pellets be between 1 and 2 mm because too small pellets bring about difficulties with preparation and handling. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Preparation and characterization of polyvinyl alcohol‐polyethylene oxide‐carboxymethyl cellulose blend membranes
Authors: Gupta Bhuvanesh , Agarwal Roopali , Sarwar Alam M. 
Published: May 2012

AbstractIn this study, blends of poly(vinyl alcohol) (PVA) and poly(ethylene oxide) (PEO) were prepared by solution casting method to develop membranes. The addition of carboxymethyl cellulose (CMC) led to the stabilization of PVA and PEO blend system. PVA/PEO/CMC membranes of three compositions 90/10/5, 90/10/10, and 90/10/20 were prepared and were characterized by X‐ray diffraction (XRD), thermogravimetric analysis, differential scanning calorimetry (DSC), and attenuated total reflectance‐Fourier transform infra‐red. It was found that the addition of CMC to PVA/PEO blend leads to significant visible changes in the miscibility of these two components. Swelling of blend membranes increased with the increase in concentration of CMC. The thermal stability and mechanical strength of the blended samples increased with increasing CMC content when compared with pure PVA and PVA/PEO blends. XRD and DSC showed decrease in crystallinity with the increase in CMC content. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Synthesis and application of poly(ethylene‐co‐vinylalcohol‐graft‐acetylsalicylic acid) in drug delivery domain
Authors: Alotaibi Nora M. , Lahsasni Siham , Aouak Taieb 
Published: May 2012

AbstractA series of poly(vinylalcohol‐co‐ethylene‐graft‐acetylsalicylic acid) hydrogel (Hi) of different acetylsalicylic acid (AcSa) contents were prepared by grafting of AcSa groups to poly(vinylalcohol‐co‐ethylene) in an esterification reaction and then crosslinking with oxalic acid. The Hi was characterized by the solubility test, DSC, NMR, and SEM analyses. The AcSa released by retroesterification of Hi at 37°C and at different pHs during 92 h. The results revealed that the amount of AcSa released from Hi depended on the initial content of AcSa in Hi and the pH of the media. In general, the results revealed that the PEVA‐graft‐AcSa (H2), which contained initially 1.59 mg of AcSa, released at pH 1 a lower amount of AcSa (0.08 ± 0.02 wt % of AcSa/h), stable during the longest period (85 h). On the reverse H3 which contained 2.05 mg of AcSa presented a highly efficient release rate at pH 7. This hydrogel was able to release 0.80 ± 0.05 wt % of AcSa/h, stable for about 60 h. From the first view, this finding seemed to be very important in the drug‐release domain, because the hydrogel prepared in this work was able to release a greatest amount of aspirin directly into the intestines (neutral pH). © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci, 2013
Nanocomposites based on aromatic polyesters and organically modified clay
Authors: Engelmann G. , Bonatz E. , Ganster J. 
Published: May 2012

AbstractMilled polybutylene terephthalate (PBT) and polytrimethylene terephthalate (PTT) were mixed with organically modified clay and extruded to prepare nanocomposites by melt intercalation. The modifier of the nanofiller belongs to the group of trialkylbenzylammonium cations. Manufacturing of the materials was carried out with a co‐rotating twin‐screw‐extruder at 230°C and 240°C for PTT and PBT, respectively. A concentration of 3% of the inorganic filler component in the composites was aimed at. The influence of mechanical stress during extrusion on the stability of the neat polymers was tested at different speeds of rotation between 100 rpm and 800 rpm. The composites were characterized with regard to the experimental filler content and the properties of the matrix polymers like melt and crystallization temperatures, degrees of crystallinity, intrinsic viscosities, and melt viscosities. Additionally, mechanical properties were analyzed by tensile tests and discussed in terms of processing and the filler presence. The dominance of PBT as polymer matrix was highlighted. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Efficient dyeing of silica fiber using metal‐coordinated polymeric dye rotaxane
Authors: Kim Dong Han , Zo Hye Jin , Park Jong S. 
Published: May 2012

AbstractWe prepared an azo dye rotaxane and its polymeric metal complex and successfully demonstrated their useful application for dyeing silica fiber, which exhibited high‐color strength and fairly good color fastness. These benefits were made possible by the hydrogen bonding between SiO2 and hydroxyl groups (OHs) on α‐cyclodextrin (α‐CD). Spectroscopic evidence supports the formation of polymeric metal‐complexed rotaxanes within the silica fiber. The current results are meaningful because they indicate that the proper adjustment of the interaction between CD and SiO2 can produce CD‐encapsulated dyes that provide an effective platform for depositing various metal ions on silica surfaces, which will be useful in numerous promising applications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Preparation of chitosan‐based adhesives and assessment of their mechanical properties
Authors: Patel Anil K. , Michaud Philippe , de Baynast Helene , Grédiac Michel , Mathias Jean‐Denis 
Published: May 2012

AbstractThe aim of this study is to develop chitosan‐based adhesives and to characterize their shear strength. The desirable features of such adhesives are biodegradability, biocompatibility, non‐toxicity, and anti‐microbial properties. Various eco‐friendly polyanionic polysaccharides, acids, and plasticizers, in single or multiple formulations, were associated with chitosan. The resulting crosslinked polymers were glued on some chemically treated aluminum adherends. The shear strength of these formulations was measured with the “double lap‐joint” bonding method, as it features a low‐peeling effect. The shear strength of 40.8 MPa obtained for formulations containing chitosan and glycerol plasticizer was the most significant finding in this study. This value is equivalent to that obtained with a synthetic adhesive used in industry. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Effect of phase separation on overall isothermal crystallization kinetics of PP/EPR in‐reactor alloys
Authors: Liu Yi‐Min , Xu Jun‐Ting , Fu Zhi‐Sheng , Fan Zhi‐Qiang 
Published: May 2012

AbstractIn the present work, the effect of phase separation on overall isothermal crystallization kinetics of two polypropylene/ethylene‐propylene random copolymer (PP/EPR) in‐reactor alloys was investigated. It is found that at lower crystallization temperatures (Tc), the overall crystallization rate decreases with increasing phase separation temperature (Ts). This is attributed to the lower linear spherulitic growth rate incurred by the lower PP content in the PP‐rich phase at higher Tss. In contrast, at higher Tcs, quenching from a higher Ts to Tc promotes nucleation as a result of more dramatic concentration fluctuation, leading to a faster overall crystallization rate. The overall crystallization rate of the PP/EPR in‐reactor alloy prepared by multi‐stage sequential polymerization process (MSSP) is retarded by increasing phase separation time (ts). However, prolonging phase separation time has little effect on the crystallization rate of the sample prepared by two‐stage polymerization process (TSP). This result can be attributed to the different phase separation rates of these two samples. The SAXS result confirms that at higher Tc, phase separation in the melt before crystallization can retard crystallization, when compared with the directly quenched samples. It is also found that the phase‐separated PP/EPR in‐reactor alloys exhibit a larger long period because of more amorphous phases included between the lamellar crystals. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Acrylonitrile/vinyl acetate copolymer nanofibers with different vinylacetate content
Authors: Cetiner Suat , Sen Selda , Arman Burcu , Sarac A. Sezai 
Published: May 2012

AbstractIn this study, free radical copolymerization of acrylonitrile (AN)–vinyl acetate (VAc) was performed for five different feed ratio of VAc (wt %) by using ammonium persulfate (APS) in the aqueous medium. The effect of VAc content on the spectrophotometric and thermal properties of AN–VAc copolymers was investigated by Fourier Transform Infrared–Attenuated Total Reflectance spectrophotometer (FTIR–ATR), differential scanning calorimeter (DSC), and thermal gravimetric analyzer (TGA). Thermal stability of homopolymer of AN is improved after being copolymerized. The electrospun P(AN‐co‐VAc) nanofibers were fabricated and the effect of VAc content on the morphologic properties of nanofibers was studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The viscosity of the solution had a significant effect on P(AN‐co‐VAc) electrospinning and the nanofiber morphology. The average diameters of P(AN‐co‐VAc) nanofibers decreased 3.4 times with increasing feed ratio of VAc wt %. The P(AN‐co‐VAc) electrospun nanofiber mats, with the feed ratio of 30 wt % VAc, can be used as a nanofiber membrane in filtration and as a carbon nanofiber precursor for energy storage applications due to high surface to volume ratio, high thermal stability, homogeneous, and thinner nanofiber distribution. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Similarity and grouping of perlite and zeolite abrasive fillers: A replacement test
Authors: Strzemiecka Beata , Héberger Károly , Voelkel Adam 
Published: May 2012

AbstractInverse gas chromatography was used to estimate surface activity expressed by the dispersive component of the surface free energy, γ, as well as parameters KA and KD describing surface ability to act as electron acceptor and donor, respectively. These parameters characterize the ability of the surface to specific interactions. The method was also applied to describe the magnitude of filler‐phenolic resin interaction by Flory‐Huggins parameter, χ′23. Granulation, surface area and porosity were also determined. The minimum number of parameters required to complete characterization of filler properties has been selected by principal component analysis. The usefulness of the selection for the abrasive industry has been proven. Moreover, the similarities and deviations from “an average” filler was determined by chemometric methods. Principal component analysis (PCA) and a novel procedure based on sum of ranking differences (SRD) were successfully applied for selection of the best fillers, and of advantageous parameters for characterization of the fillers. Similar and diverse fillers have been chosen based on clustering pattern by PCA and SRD. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Preparation and characterization of poly(vinyl alcohol)‐poly(vinyl pyrrolidone) blend: A biomaterial with latent medical applications
Authors: Bernal Andres , Kuritka Ivo , Saha Petr 
Published: May 2012

AbstractAqueous solutions of poly(vinyl alcohol) and poly(vinyl pyrrolidone) are blended and films are produced by casting method with the further intention of being used as bio‐materials with latent medical application. Glutaraldehyde, 4,4′‐diazido‐2,2′‐stilbenedisulfonic acid disodium salt tetra‐hydrate are used as crosslinker agents, whereas lactic acid is the plasticizer in the blend. The obtained films are characterized by differential scanning calorimetry (DSC), mechanical properties, swelling and solubility behavior. DSC measurements show that the blends exhibit a single glass transition temperature indicating that they are miscible, even in the presence of the plasticizer and crosslinker agents. By the combination of all mentioned additives, a relevant enhancement of the swelling is observed, accompanied by a stabilization of the solubility during the tested time. Finally, mechanical properties show an appropriate performance in the studied parameters. As a consequence, the obtained films could be suitable for use as medium or long‐term implants. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
The formation of asymmetric polystyrene/saponite composite nanoparticles via miniemulsion polymerization
Authors: Tong Zhaohui , Deng Yulin 
Published: May 2012

AbstractThe synthesis of asymmetric spherical nanoparticles has attracted great interest because their anisotropic structure can be used as unique building blocks for constructing advanced materials. In this article, we report the formation of hemispherical or truncated polystyrene/nanosaponite composite particles via one‐pot miniemulsion polymerization. It was found that the morphology of final composite latex particles strongly depends on the size of the nanoclay and its surface properties. Hemisphere or truncated sphere is the dominant morphology if the size of the nanoclay is larger than 100 nm. With the increase of the nanoclay content (up to 30 wt %), the fraction of hemispherical or truncated polystyrene/nanosaponite composite latex particles increased accordingly. The formation of hemispherical particles is possibly attributed to either the asymmetric growth of polymer chains on one side of the hydrophobically modified clay or the mechanical peeling‐off of large spherical particles between polymer and saponite. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Mechanical and thermal properties of graphite nanoplatelets reinforced polyarylene ether nitriles/bisphthalonitrile IPN system
Authors: Lei Yajie , Zhao Rui , Yang Xulin , Liu Xiaobo 
Published: May 2012

AbstractA new type of graphite nanoplatelets (GN) reinforced polyarylene ether nitriles (PEN)/bisphthalonitrile (BPh) interpenetrating polymer network with high strength and high toughness was synthesized and characterized. The results showed that GN and PEN had obvious synergistic effect on its properties of resulted BPh composites. Compared to pure BPh, with a loading of 10 wt % PEN and 10 wt % GN, the obtained composites exhibited excellent mechanical properties. In these systems, the flexural toughness and strength of BPh resin could be enhanced with the incorporation of PEN; meanwhile, GN could further improve the flexural modulus and thermal stability lowered by PEN. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Synthesis and characterization of the new cellulose derivative films based on the hydroxyethyl cellulose prepared from esparto “stipa tenacissima” cellulose of Eastern Morocco. II. Esterification with acyl chlorides in a homogeneous medium
Authors: El idrissi Abderahmane , El barkany Soufian , Amhamdi Hassan , Maaroufi Abdel‐Karim 
Published: May 2012

AbstractEsparto “Stipa tenacissima” cellulose esters derivatives: HECA‐COOC4H8COOC2H5, HECA‐COOC8H16COOC2H5, and HECA‐COOC6H4COOC2H5 were successfully prepared in Tetrahydrofuran (THF)/triethylamine system with a degree of substitution (DS), respectively, DSAD‐Et=0.32, DSSB‐Et=0.22, and DSTRP‐Et=0.50 using hydroxyethyl cellulose acetate (HECA; DSAC=0.50) as intermediate product, and we avoided the drawbacks of cellulose solubility. The structural modifications were investigated using Fourier transform infrared spectroscopy (FTIR), Proton nuclear magnetic resonance (1H‐NMR), Carbon‐13 nuclear magnetic resonance (13C‐NMR), and Distortionless Enhancement by Polarization Transfer 135° (DEPT‐135). The results from these analyses revealed the presence of the characteristic groups indicating that the grafting reaction was successful. The crystallinity and the structure order changes during the esterification reactions were recorded by X‐ray diffraction (XRD), it is found that the crystallinity degree decrease from 63.1% for Esparto “Stipa tenacissima” cellulose to 27.74% for HECA. The thermal stability of the esterified and unmodified cellulose samples was studied by thermogravimetric analysis (TGA)‐differential thermal analysis (DTA); the modified HECA exhibits a decrease in thermal stability relatively to the unmodified HECA, and this may be related to the groups grafted. The resulted cellulose esters HECA‐Px (x = 1, 2, or 3) were soluble in THF and present an amorphous structure justified by XRD spectra. It was noted by TGA‐DTA analysis that the cellulose esters with low melting range were proved as thermoplastic polymers. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Selective Cycloaddition of Tetracyanoethene (TCNE) and 7,7,8,8‐Tetracyano‐p‐quinodimethane (TCNQ) to Afford meso‐Substituted Phenylethynyl Porphyrins
Authors: Koszelewski Dominik , Nowak‐Król Agnieszka , Gryko Daniel T. 
Published: May 2012

Abstractπ‐Extended TCBD‐porphyrins that contained a 1,1,4,4‐tetracyanobuta‐1,3‐diene unit were prepared by a highly efficient [2+2] cycloaddition of tetracyanoethene (TCNE) or 7,7,8,8‐tetracyano‐p‐quinodimethane (TCNQ) with meso‐substituted trans‐A2B2‐porphyrins that contained two phenylethynyl groups, followed by a retro‐electrocyclization reaction. Depending on the electronic properties of the arylethynyl groups, the cycloaddition reaction took place exclusively on either one or two ethynyl moieties with high yield. The addition of TCNQ proceeded with complete regioselectivity. The resulting π‐expanded TCBD‐porphyrins had a hypsochromically shifted Soret band and showed unique, broad absorption in the visible region.
Connectivity Preserving Flocking without Velocity Measurement
Authors: Wang Lin , Wang Xiaofan , Hu Xiaoming 
Published: May 2012

AbstractIn this paper, we address the design of a decentralized controller for connectivity‐preserving flocking, where each agent only can access to the position information of the agents within its sensing zone. An output vector, based on the position information alone, is constructed to replace the role of velocity, and some bounded attractive and repulsive forces are integrated together to design the controller. We prove that the controller not only synchronizes all agents in a stable formation, but also enables collision avoidance and connectivity preserving all of the time, when the initial condition meets certain requirements. Moreover, a leader‐follower method is used to guide the group to a desired direction, where the followers can sense the leader only if the distance between them is less than the communication radius.
Application of a 22L scale membrane bioreactor and cross‐flow ultrafiltration to obtain purified chondroitin
Authors: Schiraldi Chiara , Alfano Alberto , Cimini Donatella , Rosa Mario De , Panariello Andrea , Restaino Odile F. , Rosa Mario De 
Published: May 2012

AbstractRecently, the possibility of producing fructosylated chondroitin from the capsular polysaccharide of Escherichia coli O5:K4:H4, in fed‐batch and microfiltration experiments was assessed on a 2 L bioreactor. In this work, a first scale‐up step was set on a 22 L membrane reactor with modified baffles to insert ad hoc designed microfiltration modules permanently inside the bioreactor vessel. Moreover, the downstream polysaccharide purification process, recently established on the A¨︁KTA cross‐flow instrument, was translated to a UNIFLUX‐10, a tangential flow filtration system suitable for prepilot scale. In particular, the microfiltered permeates obtained throughout the fermentation, and the supernatant recovered from the centrifuged broth at the end of the process, were treated as two separate samples in the following ultrafiltration procedure, and the differences in the two streams and how these affected the ultrafiltration/diafiltration process performance were analysed. The total amount of K4 capsular polysaccharide was about 85% in the broth and 15% in the microfiltered permeates. However, the downstream treatment was more efficient when applied to the latter. The major contaminant, the lipopolysaccharide, could easily be separated by a mild hydrolysis that also results in the elimination of the unwanted fructosyl residue, which is linked to the C‐3 of glucuronic acid residues. The tangential ultrafiltration/diafiltration protocols developed in a previous work were effectively scaled‐up, and therefore in this research proof of principle was established for the biotechnological production of chondroitin from the wild‐type strain E. coli O5:K4:H4. The complete downstream procedure yielded about 80% chondroitin with 90% purity. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 28: 1012–1018, 2012