bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of curing on sorption and diffusion of a brake fluid in EPDM elastomer
Authors: Farahani Tahereh Darestani , Bakhshandeh Gholam Reza 
Published: August 2014

AbstractThe effect of a poly(ether glycol) brake fluid on cured EPDM (ethylenepropylene- diene monomer) elastomer based on 5-ethylidene-2-norborene has been studied. Different amounts of dicumyl peroxide (DCP) curing agent were used and the effect of ageing in a brake fluid (at 100°C for 70 h) on technical properties of EPDM have been investigated. By increasing the amount of DCP, significant changes were not observed. Tensile strength and modulus increased but elongation at break and abrasion loss decreased due to oxidative degradation and crosslinking. Hardness was constant due to the replacement of plasticizer with brake oil.
Synthesis of fructooligosaccharide-based plastic films starting from inulin
Authors: Grandtner Gerlinde , Joly Nicolas , Cavrot Jean-Paul , Granet Robert , Bandur Geza , Rusnac Lucian , Martin Patrick , Krausz Pierre 
Published: August 2014

AbstractIn this preliminary study, inulin, a fructooligosaccharide extracted from chicory roots, was converted into plastic films by acylation in homogeneous medium and under conventional heating, using methacryloyl and lauroyl chlorides as acylating reagents and N,N-dimethyl-4-aminopyridine as basic catalyst. Products were analyzed by FT-IR and 1H NMR spectroscopies to confirm their structures. A preliminary study of their thermal properties was also achieved.
Molar mass characterization of hydrophilic copolymers, 2 Size exclusion chromatography of cationic (meth)acrylate copolymers
Authors: Adler Martina , Pasch Harald , Meier Christian , Senger Raimund , Koban Hans-Günter , Augenstein Michael , Reinhold Günter 
Published: August 2014

AbstractA robust and reproducible method for the molar mass analysis of cationic copolymers based on dimethylaminoethyl methacrylate or trimethylammonioethyl methacrylate and different (meth)acrylates has been developed. Size exclusion chromatography (SEC) using a novel polyester-based packing as the stationary phase and dimethylacetamide (DMAC) as the mobile phase yields highly accurate results for copolymers with an amino comonomer content up to 50 wt.-%. To suppress the different polar and ionic interactions between sample molecules, stationary phase and eluent, DMAC was modified with LiBr and tris(hydroxymethylamino) methane (TRIS). Calibrating the SEC system with poly(methyl methacrylate) of narrow polydispersity, molar masses were obtained that are in good agreement with viscosity data. Reproducibility and robustness of the novel method were proven by running samples for an extended period of two weeks.
Calorimetric investigation of the phase behaviour of the binary system 7-mPEG 5000-succinyloxymethyloxycarbonyl- Paclitaxel (PP7)/water
Authors: Sohn Jung-Sun , Choi Soo-Kyung , Jo Byung-Wook , Schwark Kirsten , Hess Michael 
Published: August 2014

AbstractPaclitaxel is an antineoplastic agent derived from the bark of the Pacific Yew Tree (Taxus brevifolia). Oral administration of the pure drug is problematic as it has a poor absorption due to its poor solubility in aqueous media. A specific water-soluble prodrug - PP7 - has been introduced by coupling the drug with a water-soluble polymer. For any kind of medical application and administration, knowledge of the binary isobaric phase-diagram is important since it gives information about solubility, phase transitions and the corresponding compositions. The system PP7 + H2O was studied calorimetrically from -20°C and shows the typical behaviour of an eutectic system. The properties of the phase diagram are discussed in view of other solution properties of the system presented earlier.
Preparation of fluorescent polymer particles by emulsion polymerization
Authors: Gu Shunchao , Anzai Naoto , Nagao Daisuke , Kobayashi Yoshio , Konno Mikio 
Published: August 2014

AbstractCore-shell type fluorescent polymer particles were produced in multi-step emulsion polymerization. Cross-linking was introduced to the shell to suppress leakage of fluorescent dyes contained in the core particles. First, fluorescent polymer particles were synthesized by emulsion copolymerization of styrene (St) and butyl acrylate (BA) with an anionic surfactant (SE1025A) initiated by ammonium persulfate (APS) in the presence of pyrene. The concentrations of St, BA, SE1025A and APS were 550, 89, 8.2 and 5 mol/m3 water, respectively. Then the fluorescent particles were covered with cross-linked polymer by emulsion copolymerization of St, BA and divinylbenzene (DVB) with SE1025A emulsifier. In the polymerization, a mixture of St, BA, SE1025A and DVB was added dropwise to the reaction system. The average size of cross-linked fluorescent particles ranged from 50 to 70 nm. The fluorescence intensity of the particles prepared in a pyrene concentration range of 8 - 20 mol/m3 water increased linearly with pyrene concentration. Fluorescence intensities of the particles prepared with and without DVB were also measured. The cross-linked polymer formed by DVB addition drastically suppressed the intensity drop caused by dye leakage almost to one-third of the intensity drop measured for particles prepared without DVB addition.
Microwave-assisted synthesis of channel-containing polymeric materials
Authors: Klink Michael , Kolb Ute , Ritter Helmut 
Published: August 2014

AbstractIron shows fast heat development under microwave (MW) irradiation. This property was used to start polymerization reactions on the surface of iron fibres. MW irradiation of metal fibres, which are located in a monomer solution consisting of methyl methacrylate, ethylene glycol dimethacrylate, N,N’-azoisobutyronitrile and toluene led to the formation of polymer on the metal fibre surface. After dissolving the covered iron component in hydrochloric acid, a channelcontaining polymeric material was obtained. Scanning electron microscopy showed a smooth material with rough inner channels. These internal surface structures were caused by the rough surface of the metal fibres.
Microwave-assisted nitroxide-mediated polymerization of alkyl acrylates
Authors: Leenen Mark , Wiesbrock Frank , Hoogenboom Richard , Schubert Ulrich S. 
Published: August 2014

AbstractNitroxide-mediated polymerizations of methyl and tert-butyl acrylate were performed in a single-mode microwave reactor at 120°C. The polymerizations could be carried out in a controlled way in concentrated solution (approx. 50 wt.-% of monomer) up to monomer conversions of around 90%. Monomer conversion followed first-order kinetics in the case of tert-butyl acrylate. For methyl acrylate, it seems that the kinetics obeyed the persistent radical effect. The polymers obtained from this controlled radical polymerization technique exhibited narrow molecular weight distributions (indicated by polydispersity indices below 1.3).
Drug-loaded ultrafine poly(vinyl alcohol) fibre mats prepared by electrospinning
Authors: Zhang Chunxue , Yuan Xiaoyan , Wu Lili , Sheng Jing 
Published: August 2014

AbstractSubmicron poly(vinyl alcohol) (PVA) fibre mats embedded with Aspirin and bovine serum albumin (BSA) were prepared by electrospinning of their aqueous solutions. Fibre morphology was investigated by scanning electron microscopy. The composition of the fibre mats was characterized by Fourier transform IR spectroscopy and X-ray photoelectron spectroscopy. The in vitro drug release was investigated by immersing the fibre mats in phosphate buffer solution at 37°C. Results indicated that the morphology of fibre mats was influenced by the amount of drug, and more beaded and irregularly shaped fibres were found with increasing drug amounts. There were drug molecules distributed on the surface of the PVA fibres. Studies of in vitro drug release showed that both Aspirin and BSA were released more quickly from PVA fibre mats than from PVA films because of the large surface area and high porosity of the fibre mats.
A highly efficient, solvent-free and energy-effective method of cellulose acetylation
Authors: Memmi Abdelmajid , Granet Robert , Champavier Yves , Krausz Pierre 
Published: August 2014

AbstractAcetylation of cellulose by acetic anhydride was found to be catalysed quantitatively by iodine under solvent-free conditions at room temperature. Cellulose acetates were characterised by 1H NMR spectroscopy.
Poly(L,L-lactide) and poly(L,L-lactide-co-glycolide) microparticles by dialysis
Authors: Gadzinowski Mariusz , Sosnowski Stanislaw , Slomkowski Stanislaw 
Published: August 2014

AbstractFormation of poly(L,L-lactide) (PLLA) and poly(D,L-lactide-co-glycolide) (PLGA) microparticles by dialysis from 1,4-dioxane, tetrahydrofuran (THF), acetonitrile, dimethyl sulfoxide (DMSO), and dimethylformamide (DMF) against water has been investigated. In some instances microparticles were obtained from a mixture of the above-mentioned polyesters and PLLA-block-polyglycidol-blockpoly( ethylene oxide) triblock copolymer containing a hydrophobic PLLA block as well as hydrophilic polyglycidol and poly(ethylene oxide) blocks, the former with functional -OH groups. The effects of the nature of polyester, solvent and concentration of triblock copolymer on particles morphology, size, size distribution, and degree of crystallinity have been determined. Dialysis of PLGA yielded particles in the form of microspheres regardless of the solvent. Diameters of these particles were in the range of 0.36 - 1.77 μm and particles’ diameter polydispersity (Dw̅/Dn̅ ) varied from 1.37 to 2.04, depending on the solvent. In the case of PLLA, microspheres were obtained only by dialysis from 1,4-dioxane solutions. Dialysis of PLLA solutions in THF, acetonitrile and DMF yielded particles in the form of microcrystals. In the case of dialysis of PLLA solutions in DMSO, the product was in form of crystalline flakes of c. 1 μm thickness. Microspheres composed of PLGA were amorphous. The degree of crystallinity of microparticles from PLLA was in the range of 39% - 72%.
Tuning morphologies of thermoset / thermoplastic blends Part 1: Kinetic modelling of epoxy-amine reactions using amine mixtures
Authors: Lahlali Nadir , Dupuy Jérôme , Dumon Michel 
Published: August 2014

AbstractDifferent epoxy amine networks based on a mixture of diamine hardeners have been studied and their kinetic behaviour was modelled in order to understand the global and particular behaviour of each diamine in such blends. 4,4’-Diaminodiphenylsulfone (DDS) and 4,4’-methylenebis-(3-chloro-2,6- diethylaniline) (MCDEA) were used for this study by varying the DDS molar ratio from 0% to 50%. The determined kinetic model allowed us to calculate the composition for each diamine of the reactive epoxy-amine system in the whole range of epoxy conversions. Then the influence of 10% thermoplastic additive was checked and it was found to be negligible in the kinetic behaviour.
Tuning morphologies of thermoset / thermoplastic blends Part 2: Phase separation of poly(vinyl methyl ether), PVME, using amine mixtures as thermoset hardeners
Authors: Lahlali Nadir , Dupuy Jérôme , Dumon Michel 
Published: August 2014

AbstractPart 2 of the study investigates morphologies of epoxy thermoset / thermoplastic blends obtained with formulations of the thermoset hardeners. The thermosetting matrices are composed of one epoxy resin crosslinked by a mixture of two aromatic diamine hardeners, namely MCDEA+DDS or MDEA+DDS (DDS is 4,4’-diaminodiphenylsulfone, MCDEA is 4,4’-methylenebis-(3-chloro-2,6- diethylaniline), MDEA is 4,4’-methylenebis-(2,6-diethylaniline). The blends are made at a fixed concentration of thermoplastic (poly(vinyl methyl ether), PVME, 10wt%) whereas three different cure temperatures are chosen and the matrix composition is varied by the ratio of DDS. DDS is a PVME-insoluble diamine whereas MDEA or MCDEA are PVME-soluble diamines.The domain size of the PVME nodules is tuned from a few micrometers down to sub micron sizes, typically between 50 and 80 nm. We attempt to explain this evolution thanks to the difference in the reactivity of the amines with the epoxy oligomer coupled to the difference in miscibility of each amine towards PVME. The kinetic study developed in Part 1 of this work is used to calculate the concentrations of each amine along the reaction time and their rate of incorporation in the polymer network. The latter parameter is shown to be the limiting factor for obtaining a nano phase separation.
Phase Behavior of Weakly-segregated Multiblock Copolymers with Two-scale Periodic Architecture
Authors: Kuchanov Semion , Pichugin Vladimir , Brinke Gerrit ten 
Published: August 2014

AbstractThe phase behavior of a melt of periodic two-scale multiblock copolymers has been theoretically studied in the framework of the Weak-Segregation Limit theory. The effect of the structural symmetry of the macromolecules on the vertex functions of the Landau free energy expansion is considered in detail. The existence of a thermodynamically stable mesophase with a two length-scale space periodicity has been revealed for a melt of monodisperse periodic heteropolymers.
First GPC results of terpyridine based chain extended supramolecular polymers: comparison with viscosity and analytical ultracentrifugation
Authors: Meier Michael A. R. , Hofmeier Harald , Abeln Caroline H. , Tziatzios Christos , Rasa Mircea , Schubert Dieter , Schubert Ulrich S. 
Published: August 2014

AbstractThe molecular weight of an extended metallo-supramolecular polymer, based on a α,ω-bis-terpyridine-poly(ethylene glycol) polymer linked via ruthenium(II) ions, was determined by gel permeation chromatography, viscosimetry as well as analytical ultracentrifugation. An optimized GPC method was applied for the first time to this kind of chain extended supramolecular polymers and the obtained results showed a good agreement with viscosimetry and analytical ultracentrifugation. A chain extended polymer with an average molecular weight of around 140 000 was found. These results clearly demonstrate that well-soluble high-molecular-weight metal-containing coordination polymers that are based on well-defined telechelics can be synthesized and fully characterized.
Thiodiethylene glycol based polyesters: synthesis and thermal characterization
Authors: Lotti N. , Finelli L. , Messori M. , Munari A. 
Published: August 2014

AbstractPoly(thiodiethylene terephthalate) (PSDET), poly(thiodiethylene adipate) (PSDEA), poly(diethylene terephthalate) (PDET) and poly(diethylene adipate) (PDEA) for comparison were synthesized and characterized in terms of chemical structure and molecular weight. The thermal behavior was examined by thermo gravimetric analysis and differential scanning calorimetry. All the polymers showed a good thermal stability, even though lower for the sulfur-containing polyesters. At room temperature they appeared as semicrystalline materials, except PDEA, which was an oil; the effect of substitution of ether oxygen atoms with sulfur ones was a lowering in the Tg value, an increment of melting temperature and an increase of crystallization rate. The results were explained as due to the presence of flexible C-S-C bonds in the polymeric chain.
Study on synthesis and characterization of novel optically active poly(amide-imide)s based on bis(p-aminobezoic acid)-N-trimellitylimido-S-valine via direct polycondensation
Authors: Mallakpour Shadpour , Kolahdoozan Majid 
Published: August 2014

AbstractN-Trimellitylimido-S-valine (3) was prepared by reaction of trimellitic anhydride (1) with S-valine (2) in acetic acid solution at refluxing temperature. This diacid was reacted with thionyl chloride and N-trimellitylimido-S-valine diacid chloride (4) was obtained in quantitative yield. The reaction of this diacid chloride with p-aminobenzoic acid was carried out in dry tetrahydrofurane and bis(paminobenzoic acid)-N-trimellitylimido-S-valine (5) was obtained as a novel optically active amide-imide diacid monomer in high yield. The direct poly condensation of amide-imide diacid monomer with aromatic diamins such as 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ether, benzidine, 4,4'-diaminodiphenyl methane, 1,4- phenylene diamine and 2,5-diamino toluene was carried out in tosyl chloride/ pyridine/dimethylformamide system. The resulting novel optically active poly(amide-imide)s (PAIs) with inherent viscosities ranging from 0.24-0.76 dLg-1, were obtained in good yield. All of these polymers were fully characterized with FTIR spectroscopy and specific rotation. Some elemental analysis, thermal properties and 1H-NMR of these new optically active PAIs are also reported.
Investigation of the ion permeability of poly(p-xylylene) films
Authors: Hanefeld Phillip , Sittner Frank , Ensinger Wolgang , Greiner Andreas 
Published: August 2014

AbstractThe ion permeability of poly(p-xylylene) (PPX, parylene-N®) thin films was investigated using a cyclovoltammetric setup. Iron rods of different surface roughness were coated with PPX films of different thickness (140 - 700 nm) by vapour phase deposition (Gorham process). The presence of pinholes in PPX films deposited as described was analyzed by ion permeability according to cyclovoltammetric measurements. Current densities were directly related to the area of iron not covered by the polymer. It was found that films deposited on iron surfaces by the Gorham process showed significant ion permeability for film thicknesses below 500 nm and no permeability at all for films equal to or thicker than 700 nm, which indicated the absence of pinholes of PPX films of 700 nm thickness. Furthermore, films of 140 nm were deposited on iron surfaces of different roughness (the mean roughness was measured to be 102 nm, 103 nm and 105 nm). Current density increased by the increase in roughness, which confirmed that pinhole formation correlated with surface roughness.
Chemistry and Applications of Phosphorylated Chitin and Chitosan
Authors: Jayakumar R. , Reis R. L. , Mano J. F. 
Published: August 2014

AbstractChitin and chitosan are natural based non-toxic, biodegradable and biocompatible polymers and have been used in biomedical areas in the form of sutures, wound healing materials and artificial skin, and for the sustained release of drugs as well as in various industrial applications. However, practical use of these polymers has been mainly confined to the unmodified forms. Recently, there has been a growing interest in chemical modification of chitin and chitosan to improve their solubility and widen their applications. Among them, phosphorylated chitin and chitosan have attracted considerable interest because of their various advantages: anti-inflammatory property, ability to form metal complexes, blood compatibility and formation of anionic polyelectrolyte hydrogels. The purpose of this review is to take a closer look of different synthetic methods of phosphorylated chitin and chitosan and their potential applications in environmental, food, fuel cell, and biomedical fields. Based on current research and existing products, some new and futuristic approaches in this context area are discussed.
Development of Fast Gradient Separations for Different Polymethacrylates
Authors: Brüll Adele , Pasch Harald , Bashir Mubasher 
Published: August 2014

AbstractLiquid chromatography of polymers is traditionally a slow technique with analysis times of typically 30 min per sample. To adapt liquid chromatographic techniques to combinatorial materials research the sample throughput must be significantly increased. Preferably, the analysis time per sample is to be reduced to a few minutes. Short analysis times can be achieved using high resolution stationary phases, high flow rates, and fast gradients. The present work demonstrates that gradient HPLC of polymethacrylates can be accomplished in less than 2 min. The fast separation of poly(methyl methacrylate), poly(i-propyl methacrylate), poly(n-butyl methacrylate), poly(tbutyl methacrylate), and poly(n-decyl methacrylate) is conducted on a short monolithic stationary phase using a flow rate of up to 7 mL/min. The optimization of the gradient is conducted by running a number of linear gradients and by simulating an optimum step gradient. Further modification of the simulated gradient results in the desired short analysis times.
Direct Polyesterification of Pyridine-2,6-Dicarboxylic Acid and Poly(ethylene glycol) using Picryl Chloride as Condensing Agent
Authors: Doan Nhung T.H. , Montembault Véronique , Soutif Jean-Claude 
Published: August 2014

AbstractHigh molecular weight polyesters derived from pyridine-2,6-dicarboxylic acid and poly(ethylene glycol) have been synthesized under mild conditions (room temperature, atmospheric pressure) in the presence of picryl chloride and pyridine. Reaction conditions including solvent, trap agent, reaction time and amount of reagents were investigated using poly(ethylene glycol) 400 as dialcohol comonomer. Detailed analysis of the MALDI-TOF mass spectra of the obtained polyesters has revealed a predominant fraction of macrocycles for a picryl chloride/acid functions molar ratio lower than 1.5. The reaction yielded the most favourable results using 1.5 equivalents of picryl chloride with respect to the acid functions and 4-(N,N-dimethylamino)pyridine as HCl scavenger. The molecular weights of the polyesters at the peak maximum of the SEC trace are in the range of 4 800-80 000 depending on the nature of the comonomer poly(ethylene glycol). Syntheses of an aliphatic and aromatic polyester were also examined.
Plasma polymerization of tetrafluoroethylene – towards CF2 dominated fluorocarbon films
Authors: Nitschke Mirko , Uhlmann Steffi , Schulze Roland , Werner Carsten 
Published: August 2014

AbstractFluorocarbon films with an exceptionally high CF2 content were obtained by plasma polymerization using a low pressure radio frequency discharge operated with a mixture of argon and tetrafluoroethylene. Substrates were placed in a remote position downstream the discharge. Gas pressure, discharge power, substrate position, gas composition and substrate temperature were changed to alter the chemical structure of the plasma polymers. The properties of the films were characterized by X-ray photoelectron spectroscopy (XPS), spectroscopic ellipsometry and contact angle goniometry. A pronounced increase of the CF2 content was obtained for elevated substrate temperatures and increased amounts of tetrafluoroethylene in the process gas. Applied as a model surface in studies of interfacial phenomena on polytetrafluoroethylene (PTFE), transparent PTFE-like thin films enable the use of numerous optical techniques not applicable to common PTFE foils.
Synthesis and some Mechanical Properties of Polysulfobetaine – Polyacrylamide Double Networks
Authors: Georgiev George , Dyankova Konstantina , Vassileva Elena , Friedrich Klaus 
Published: August 2014

AbstractDouble polymer networks (DNs) with poly(N-(3-sulfopropyl)-Nmethacroyloxyethyl- N,N-dimethylammonium betaine) component as a high density cross-linking agent were synthesized by thermoinitiated cross-linking polymerization. Good mechanical properties of the produced DNs were established. These, in combination with an excellent biocompatibility of polyzwitterions, open a possibility for wide biomedical applications of these materials. It is also shown that the mechanical properties could be controlled by the factors (cross-linking agent and monomer concentrations, temperature and time for the cross-linking polymerization, order of single network formation) influencing the junction point densities of the two single networks and on the microphase separation taking place during the formation of the second single network. Specific dipole-dipole interaction between polyzwitterion monomer units as a reason for this separation is a distinct peculiarity of poly(N-(3-sulfopropyl)-N-methacroyloxyethyl-N,Ndimethylammoniumbetaine)/ poly(acrylamide) double networks in comparison to poly(2-acrylamido-2-methylpropanesulfonic-acid)/poly(acrylamide) ones.