bluuebunny/crossref_metadata_2025_split huggingface dataset:
Elaboration of stimuli responsive core-shell magnetic latexes from oil in water ferrofluid emulsion
Authors: Pibre Guillaume , Hakenholz Luc , Braconnot Sebastian , Mouaziz Hanna , Elaissari Abdelhamid 
Published: August 2014

AbstractThis manuscript describes the elaboration of temperature sensitive highly magnetic latex particles. The particle core is crosslinked polymer matrix containing iron oxide nanoparticles. The shell is a combination of highly crosslinked hydrophobic polymer and crosslinked stimuli responsive hydrophilic polymer. The polymerization was performed in two steps: the elaboration of seed magnetic latex particles for oil in water magnetic emulsion and (ii) the functionalization of the obtained magnetic latexes via seed polymerization in the presence of water soluble reactants. The obtained final core-shell latexes exhibit the following properties: The iron oxide content is above 50 wt.%. The size distribution is governed by the size distribution of the used oil in water magnetic emulsion. The thermal sensitivity of the shell is due to the presence of poly(N-isopropylacrylamide). The cationic character of the outer layer shell is due to the use of cationic initiator and amino containing monomer.
New optically active poly(amide-imide)s from N,N΄- (bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracrboxylic)-bis-L-valine diacid and aromatic diamines: synthesis and properties
Authors: Faghihi Khalil , Shabanian Meisam , Hajibeygi Mohsen 
Published: August 2014

AbstractNew optically active aromatic poly(amide-imide)s (PAIs) were prepared from newly synthesized N,N΄-(bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracrboxylic)-bis-Lvaline diacid (4) via polycondensation with various aromatic diamines. The diacid (4) was synthesized by the condensation reaction of bicyclo[2,2,2]oct-7-ene- 2,3,5,6-tetracarboxylic dianhydride (1) with L-valine (2) in acetic acid. All polymers were obtained in quantitative (high) yields with inherent viscosities of 0.24-0.36 dL/g. All of these polymers were highly organosoluble in solvents like N-methyl-2- pyrrolidone (NMP), dimethylformamide (DMF), N,N'-dimethylacetamide (DMAc) and dimethylsulfoxide (DMSO) at room temperature and were fully characterized by means of NMR spectroscopy, FTIR spectroscopy, elemental analyses, inherent viscosity, solubility test, specific rotation and thermal properties of the poly(amideimide) s were investigated using TGA/DTG.
Modification of styrene polymer by attaching suitable groups as side chain
Authors: Mahkam Mehrdad , Massoumi Bakhshali , Mirfatahi Hossien 
Published: August 2014

AbstractChemical modification of inexpensive commercial polymers, such as styrene, is a safe methodology to obtain new copolymers. The 4-chloromethyl styrene (CMS) was copolymerized with styrene (in various mole ratios) by free radical polymerization method at 70 ºC using α,α-azobis(isobutyronitrile) (AIBN) as an initiator. The azide ion was covalently attached to the obtained copolymers with replacement of all the chlorine atoms in CMS units. The 1,3-dipolar click cycloaddition reaction between azido polymers and dimethyl acetylene dicarboxylate (DMAD) yielded polymers with 1,2,3-triazoles in side chain. The polymers, obtained in quantitative yields, were characterized by FT-IR and 1H NMR spectroscopy; thermogravimetric analysis (TGA) and GPC studies. The thermogravimetric analysis (TGA) indicated that the thermal stability of copolymers increases with incorporation of 1,2,3-triazole groups in side chains of copolymers.
Synthesis and characterization of novel fluorinated polybenzoxazoles derived from 2,5-difluoroterephthalic acid
Authors: Huang Xiao-Song , Qing Feng-Ling 
Published: August 2014

AbstractA new serious of fluorinated polybenzoxazoles (PBOs) were prepared from 2,2-bis(3-amino-4-hydroxyphenyl) hexafluoropropane together with 2,5- difluoroterephthalic acid (DFTA) and terephthalic acid by the one-pot polycondensation in polyphosphoric acid. The resulting PBOs showed good solubility in many common organic solvents and the thermal stability of PBOs was improved by the introduction of DFTA monomer.
Fabrication and investigation of core-sheath polymer/ polyaniline composite nanofibers
Authors: Huang Huimin , Li Zhenyu , Wang Wei , Yang Fan , Li Shangyu , Wang Ce 
Published: August 2014

AbstractThree types of coaxial polymer/polyaniline (PANi) fibers were prepared by in situ polymerization of aniline on the electrospun poly(methyl methacrylate) (PMMA), polystyrene (PS) and polyacrylonitrile (PAN) fibers, respectively. Scanning electron microscopy (SEM) and transmission electron microscope (TEM) were applied to characterize the morphologies of these core-sheath structures. Under identical polymerization conditions, a thicker layer of PANi was deposited on the hydrophilic PAN fibers than those on the other two hydrophobic polymer core fibers. The results revealed that the nature of the polymer cores could influence the formation of the coaxial fibers, which may provide a deeper insight into the formation of core-sheath nanostructures.
Flame retardance and thermal properties of a novel phosphorus-containing unsaturated polyester resin/SiO2 hybrid nanocomposite
Authors: Zhang Chen , Liu Shu Mei , Huang Jun Yi , Zhao Jian Qing 
Published: August 2014

AbstractA novel phosphorus-containing unsaturated polyester resin/SiO2 hybrid nanocomposite was prepared from the in-situ curing of unsaturated polyester resin (UP) and triethoxysilane (DI) which was synthesized from the nucleophilic addition reaction of 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO) and 3- (trieoxysilyl) isocyanate(icteos). The formation of unsaturated polyester resin/SiO2 hybrid nanocomposite (UP-DI) was confirmed by infrared spectra (FTIR) and scanning electron microscopy (SEM). With the increase of DI contents, the limiting oxygen index (LOI) value of the cured UP-DIs was raised from 19 to 29, suggesting a significant improvement in flame retardance. The improved flame retardance could also be revealed by the variations of weight and morphology of char residues. Thermogravimetric analysis (TGA) both in air and in nitrogen was used to estimate mechanism of thermal degradation and activation energy (Ea) of different degree of conversion (α) was calculated by Ozawa’s method. The UP-DI containing 10%DI (UP-DI10) had higher Eathan the pure UP as α>5% because the degradation mechanism was altered by the incorporation of DI.
The reflection of the texture of swollen polymer matrix on the release of incorporated substance
Authors: Pavli Matej , Kristl Julijana , Dolenc Andrej , Zvonar Alenka , Vrečer Franc , Kosel Franc , Baumgartner Saša 
Published: August 2014

AbstractOur aim was to investigate the texture of hydrated biopolymer matrices that are now being considered in the design of pharmaceutical controlled-release dosage forms, in order to determine their influence on the release of an active compound. Prolonged release of pentoxifylline, a highly soluble drug, is needed for once-daily administration to achieve its therapeutic effect. For this purpose, pentoxifylline was incorporated in a polymer matrix made of a combination of xanthan and locust bean gum (XLBG), both of which are of biotechnological origin. Different methods were used to investigate the interplay of the XLBG gel structure characteristics in the absence and presence of 200 mM CaCl2 on pentoxifylline release: drug-release studies, determination of swelling, erosion, and viscoelasticity of the gel, as well as its texture analysis and microscopic imaging. From the results obtained, the following conclusions can be drawn: the pentoxifylline release from XLBG matrices in water was prolonged for 24 h whereas from the control lactose formulation was completed within 30 min. The presence of Ca2+ ions in water resulted in faster pentoxifylline release, in spite of less swelling and erosion. However, the rheology, texture analysis and scanning electron microscopy revealed that in the presence of the Ca2+ ions the gel layer of the XLBG was more cohesive and thinner, as the attraction for water molecules was lower due to the condensation of counter-ions on the xanthan carboxylic-moieties, and consequently greater interpolymer interactions. Therefore, relatively larger amounts of free water molecules were available within the XLBG hydrogel in the presence of Ca2+, allowing faster drug dissolution and diffusion. Here, the presence of Ca2+ ions had a completely opposite effect on XLBG gel structure and drug release in comparison with other more investigated matrix polymers like alginate or non-ionic cellulose ethers. A firm matrix structure that is accompanied by low swelling and erosion cannot guarantee a more prolonged drug release.
A simple procedure to tailor the compositional gradient of copolymeric materials
Authors: Reinecke Helmut , Aguilar María Rosa , Güven Güldem , Piskin Erhan , Gallardo Alberto 
Published: August 2014

AbstractCopolymeric structures with compositional gradient were produced by “in situ” radical polymerization -in water and with redox initiation- of acrylic acid (AA) and 2-hydroxyethyl methacrylate (HEMA) in the presence of an inhibitor (hydroquinone). The inhibitor has a key role in controlling the mixing of precursor solutions because it produces a retardation of the polymerization. Raman spectral analysis confirmed the changes in the composition along the long axis of the produced cylindrical materials. Compression tests were also performed, exhibiting the gradient and reference material’s unique properties, which were well correlated to the compositional pattern.
A novel shape memory polymer based on conetworks
Authors: Li Zonghui , Pan Yi , Zhang Peng , Zheng Zhaohui , Ding Xiaobin , Peng Yuxing 
Published: August 2014

AbstractA novel shape memory polymer based on conetworks (CNs) was synthesized. These conetworks consisting of poly(methyl methacrylate) and poly (ethylene glycol) diacrylates showed excellent shape-memory properties with a recovery ratio of nearly 100%. Moreover, different shape memory effects were discovered in different mediums due to their amphiphilic properties. In addition, a large storage modulus ratio above and below the glass transition temperature(Eratio), which probably means excellent shape memory effect, were obtained due to the designed CN structure whether crystallization existed or not. It is quite different from the traditional methods to achieve large Eratio values. The versatility of shapememory conetworks potentially provides us a new route to prepare shape memory materials.
Surface-initiated atom-transfer radical polymerization from polyethersulfone membranes and their use in antifouling
Authors: Li Liang , Yan Guoping , Wu Jiangyu , Yu Xianghua , Guo Qingzhong 
Published: August 2014

AbstractA simple one-step method for the chloromethylation of polyethersulfone (PES) under mild conditions provided surface benzyl chloride groups as the active initiators for the surface-initiated atom-transfer radical polymerization (ATRP) to tailor the functionality of the PES membrane. Functional hydrophilic polymer brushes of poly(ethylene glycol)monomethacrylate (PEGMA) and sodium 4- styrenesulfonate (NaStS), as well as their block copolymer brushes, were prepared via surface initiated ATRP from the chloromethylated PES surfaces. X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) were used to characterize the surface-modified membranes. The PEGMA-grafted PES membranes showed great protein resistance to protein adsorption compared to the pristine PES surface.
Morphology of inorganic–organic systems consisting of polyhedral oligomeric silsesquioxanes (POSS) and polyamide 6
Authors: Alongi Jenny , Monticelli Orietta , Russo Saverio , Galy Jocelyne , Gérard Jean-François 
Published: August 2014

AbstractPreparation of inorganic-organic hybrids made of polyhedral oligomeric silsesquioxanes (POSS) and polyamide 6 (PA6) has been attempted either by melt mixing of the two components or by in-situ polymerization of -caprolactam (CL) in presence of POSS. The samples have been characterized by wide angle X-ray diffraction (WAXD) and scanning electron microscopy (SEM) techniques. Specific processing conditions (namely, high T in presence of different shear stresses) have been tested. Two different approaches for melt mixing have been used and the morphology of the corresponding systems compared. The melt-mixed pairs prepared in the microcompounder revealed a coarse phase separation, while those made in a simple mixer did not show any perceivable POSS segregation phenomenon, as evidenced by both WAXD data and SEM investigation. Similarly, the in-situ polymerization of CL in presence of POSS did not result in any POSS self-aggregation in the polyamide matrix, achieving a very fine Si dispersion of nanometric dimensions.
Self-assembly in the solutions of poly(methyl methacrylates) end-capped with fluorophenyl groups
Authors: Gasilova Ekaterina R. , Zakharova Olga G. , Zaitsev Sergey D. , Semchikov Yury D. 
Published: August 2014

AbstractSelf-assembly of poly(methyl methacrylates) end-capped with -Ge(C6F5)3 groups (PMMA-F) has been studied in a selective solvent (acetone) by means of photon correlation spectroscopy and static light scattering. PMMA-F’s of different molecular weights (MW), were obtained by radical polymerization in the presence of a chain transfer agent, HGe(C6F5)3. At MW>130 000 conformational and hydrodynamic properties of PMMA-F’s is shown to be the same as of PMMA. At MW less than130 000 an aggregation starts: additional fraction of large scatterers appears in PCS. Large aggregates of Rh=200 - 300 nm are likely to be formed by bridged micellar clusters. Presence of large aggregates indicates a super strong segregation limit predicted in the work of Semenov et al.
Synthesis of poly(butadiene)-poly(ε-caprolactone) multiblocks based on hydroxyl telechelic poly(butadiene): composition and kinetic study
Authors: Lemoine Michael , Brachais Claire-Hélène , Boni Gilles , Couvercelle Jean-Pierre 
Published: August 2014

AbstractThermoplastic block copolymers based on poly(butadiene) and poly(ε- caprolactone) were synthesised from the ring opening polymerization of ε- caprolactone onto a polybutadiene macroinitiator. The lithium alkoxide macroinitiator results from BuLi addition on hydroxy telechelic polybutadiene (HTPB R45®) chain ends. The reaction is fast (about 5 min) and quantitative, leading to well defined copolymers with PCL/PBHT ratio varying from 45/55 and 18/82. Average molar masses range from 10 000g/mol to 26 000g/mol with PDI about 1.6. 1H NRM was used to follow the polymerization kinetic and 13CNMR was used to determine the chemical link between the blocks.
Crystallization and rheological behavior of POSS filled polypropylene
Authors: Zhou Zhiyong , Ouyang Chunfa , Zhang Yong , Zhang Yinxi , Yin Nianwei 
Published: August 2014

AbstractOctaaminophenyl polyhedral oligomeric silsesquioxane (OapPOSS) was prepared as nanofillers and filled to isotactic polypropylene (PP). Maleic anhydridegrafted PP (MAPP) was selected as compatibilizer. The morphology, crystallization, melting behavior and rheologcial behavior of PP/OapPOSS composites with or without MAPP were studied by scanning electron microscopy, differential scanning calorimetry, polarized optical microscope, oscillatory and capillary rheological analysis. The results showed that the morphology, crystallization and rheological behavior of the composites were strongly influenced by the existence of MAPP. MAPP improves the compatibility between PP and OapPOSS because of the reaction of OapPOSS with MAPP. The OapPOSS retards the crystallization of PP while promoting it when MAPP is added. MAPP could decrease the viscosity of PP/OapPOSS probably due to the weaker particleparticle interaction and interface slipping.
The influence of polymerization temperature on structure and properties of polyaniline
Authors: Yılmaz Faris , Küçükyavuz Zuhal 
Published: August 2014

AbstractThe influence of polymerization temperature (from -25 to +25 oC) on molecular weight, crystallinity, electrical conductivity, thermal and morphological properties of polyaniline has been investigated. Aniline was oxidized in an aqueous medium with ammonium persulfate and 1.0 M hydrochloric acid. The reaction mixture freezes below -10 oC and hence lithium chloride was used in sufficient amount to prevent freezing. As the reaction temperature decreases, both the molecular weight of polyaniline and its crystallinity increase. Thermal studies show a common three step decomposition pattern irrespective of the temperature used during synthesis. The morphology of polyaniline changes from granular (reaction in liquid medium) to tubular (polymerization in the frozen state). Thermal analysis indicated that the polyaniline stability increased with decreasing synthesis temperatures. Electrical conductivity of polyaniline was found to be independent of the polymerization temperature and, consequently, of the molecular weight.
Homo- and copolymers of 3-tosyloxymethyl-3-methyl oxetane (TMMO) as precursors to energetic azido polymers
Authors: Barbieri Ugo , Keicher Thomas , Polacco Giovanni 
Published: August 2014

AbstractPoly(3-azidomethyl-3-methyloxetane) and its copolymers with 3,3- bis(azidomethyl)oxetane were synthesized by cationic polymerization from 3- tosyloxymethyl-3-methyl oxetane and 3,3-bis(bromomethyl)oxetane, using a polyol as initiator and boron trifluoride complex as catalyst, followed by azidation. The final objective is the synthesis of an energetic binder to be used for rocket propellants and therefore the effects of different initiator/catalyst systems on important properties, like, i.e., the molecular weight distribution and the functionality of the polymer, were investigated. It was found that, even though both the operating conditions and the catalytic system were chosen in order to grant the living character of the polymerization, the latter seems to be prevalently driven by an “active chain end” mechanism. In particular, this may lead to the undesired formation of a small quantity of oligomers and to the presence of non-hydroxylic chain-end functionalities. Nevertheless, the average number of OH groups can be strictly controlled when boron trifluoride tetrahydrofuranate is used as catalyst.
Characterization of thin films of regioregular poly(alkylthiophene)s bearing optically active substituents
Authors: Angiolini Luigi , Brazzi Alice , Grenci Valeria , Salatelli Elisabetta , Catellani Marinella , Luzzati Silvia 
Published: August 2014

AbstractThe spectroscopic behavior of thin films of regioregular poly(alkylthiophene)s bearing an optically active alkyl group has been investigated in the solid state under different sample preparation procedures. The experimental results are interpreted in terms of influence of the side-chain substituents on the extent of planarity of the polymeric chains and the formation of optically active chiral aggregates.
Study of the compounding process parameters for morphology control of LDPE/layered silicate nanocomposites
Authors: Coiai Serena , Scatto Marco , Bertoldo Monica , Conzatti Lucia , Andreotti Leonardo , Sterner Marion , Passaglia Elisa , Costa Giovanna , Ciardelli Francesco 
Published: August 2014

AbstractA careful insight into melt compounding procedure is proposed in order to achieve a better understanding and control of the dispersion and orientation mechanisms of organo-clay platelets into LDPE nanocomposites. The method involved is the preparation of a maleic anhydride grafted polyethylene masterbatch containing 10 wt% organo-clay via twin-screw extrusion. A substantial nanodispersion and orientation of clay platelets was obtained as observed by X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses. Moreover, the nanocomposites prepared by diluting the master-batch through the blend mixing with additional LDPE preserved or improved the exfoliation and lamellae orientation. Finally, the thermo-gravimetric analysis (TGA) showed a significant improvement of the thermal stability while both differential scanning calorimetry (DSC) and XRD evidenced a slight increase of the LDPE crystallinity degree with respect to neat polymer matrices thus suggesting the occurrence of orientation also for the polymer.
Frontal polymerization as a convenient technique for the consolidation of tuff
Authors: Mariani Alberto , Bidali Simone , Cappelletti Piergiulio , Caria Giuseppe , Colella Abner , Brunetti Antonio , Alzari Valeria 
Published: August 2014

AbstractFrontal Polymerization was successfully exploited as an innovative technique for the consolidation of Neapolitan Yellow Tuff, the main volcaniclastic rock of Campania region (Italy). The protocol used and the full characterization in terms of mechanical properties of the resulting consolidated stone are presented here and discussed together with the data obtained by X-ray tomography as a non destructive analytical technique for determining the internal map of the consolidated material. The proposed treatment definitely succeeded from the technical point of view resulting in an enhancement of mechanical properties.
Liquid chromatography at the critical adsorption point (LCCAP) of high molecular weight polystyrene: pushing back the limits of reduced sample recovery
Authors: Favier Arnaud , Petit Christelle , Beaudoin Emmanuel , Bertin Denis 
Published: August 2014

AbstractLow sample recovery may be one limiting parameter in Liquid Chromatography at the Critical Adsorption Point (LC-CAP) of high molecular weight polymers. We aimed at playing on different experimental parameters in LCCAP of high molecular weight polystyrenes (PS) in order to reach maximum sample recovery. The nature of adsorli and desorli, the temperature, the nature of the column surface and the pore size were studied as regard to their influence on sample recovery. Evaporative Light Scattering was used for detection. We demonstrated that almost all experimental parameters are correlated and that in any case, the lower the adsorli content, the better the sample recovery. Molecular weight limit for good sample recovery could be pushed from as low as 100 000 for the THF/cyclohexane mixture and silica columns to above 1 000 000 for the DCM/n-hexane mixture and amino-silica columns.
Track PVB membrane based on irradiation with high energy protons
Authors: Shadman Muhammad , Ziaie Farhood , Yeganegi Saeid , Niazi Behrooz , Ziaee Farshid , Majdabadi Abbas 
Published: August 2014

AbstractOne of the methods of polymeric material modification is based on the irradiation with accelerated ions. Chemical etching of ion tracks in polymers is a method which is widely used in the fabrication of micro/nano-structures with predetermined characteristics. For the present study polyvinyl butyral (PVB) porous membrane was prepared by track-etching technique. Commercially available PVB film was irradiated by 30 MeV energy protons to form latent tracks, and then etched chemically by potassium hydroxide (KOH) with the different normalities. The etching rate of PVB was related to the concentration of etching reagent, temperature and time. The porous size and shape were investigated by scanning electron microscope (SEM) after and before etching. Relationships in between the etching rate and the etching parameters were established from experimental data, and can be used to control the pore size of PVB track-etch membrane. The Pore sizes and their structures were evaluated by optical microscope (OM) and scanning electron microscope (SEM). The results have shown the micro/nano-pores formation in the PVB films. The physico-chemical properties of the irradiated samples were investigated and compared with the un-irradiated one using the FTIR and DSC and DTG systems, as well.