bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel results and potential applications of bitumen used as an additive for polyethylene
Authors: Goikoetxeaundia Goretti , Mateos Alexander , González Oscar , Muñoz María Eugenia , Santamaría Anton , Martínez Inmaculada 
Published: August 2014

AbstractA metallocene catalysed linear low density polyethylene (mLLDPE) was mixed with very low amounts of bitumen (1-2%) as an additive. Bitumen interacts with mLLDPE giving rise to a dying effect, which turns the originally white mLLDPE extrudates into black. No slippage is observed during extrusion and sharkskin is postponed as bitumen is added. “Melt strength” values of the blends, determined in melt spinning experiments, are very similar to those of mLLDPE. Accordingly good performance is expected in film-blowing process. Tensile modulus values are higher than 109 Pa. Bitumen emerges as an alternative to carbon black powder currently used to obtain black polymer films.
Thermotropic Behaviour of Liquid Crystalline Poly[n-(4’- cyanophenyl-4’’-phenoxy)alkyl acrylate] Gels in the Dry and Swollen States
Authors: Vendamme Richard 
Published: August 2014

AbstractThis paper reports the thermotropic behaviour of various side-chain liquid crystalline (LC) networks and gels of poly[n-(4’-cyanophenyl-4’’-phenoxy)alkyl acrylate]. Increasing the aliphatic spacer length tend to increase the melting temperature of the pure LC polymers. On the other hand, increasing the crosslinking density lead to a decrease and broadening of the melting transition temperature. Swelling of a liquid crystalline elastomer in a low molar weight liquid crystal (LMWLC) leads to the formation of a LC gel, with thermotropic properties drastically different from the original LC polymers and solvents. The thermotropic behaviour of such an LC gel is determined by several parameters, such as the concentration of LMWLC inside the gel and the compatibility between the two types of mesogens.
Synthesis and complete NMR characterization of methacrylateendcapped poly(ortho-esters)
Authors: Paesen Bert , Baekelandt Tom , Heller Jorge , Martins José C. , Schacht Etienne H. 
Published: August 2014

AbstractIn this paper a synthesis method for low molecular weight poly(orthoesters) with photo crosslinkable methacrylate endgroups is presented. Using this procedure, the molecular weight could be controlled and the desired endgroup functionality was introduced in a single reaction step. The detailed characterization of the molecular structure of bismethacrylate endcapped poly(ortho-esters) using NMR affords a re-evaluation of previous assignments reported for similar poly(ortho-ester) polymers. In addition, the use of diffusion filtered 1D 1H NMR spectroscopy as a simple but effective analysis tool that allows to distinguish resonance contributions from impurities and low molecular weight compounds, most probably the result of degradation, from those of the full size polymer, is demonstrated.
Structure and Mechanical Properties of Carboxylated Styrene-Butadiene Rubber (XSBR)/Pristine Clay Nanocomposites
Authors: Abdollahi Mahdi , Rahmatpour Ali , Khanli Homayon Hossein 
Published: August 2014

AbstractCarboxylated styrene- butadiene rubber (XSBR)/clay nanocomposites were prepared by mixing the XSBR latex with aqueous clay dispersion and cocoagulating the mixture. TEM and XRD were applied to characterize the structure of nanocomposites. Fully exfoliated structure was observed for the nanocomposites containing equal to or less than 10 phr (weight parts per hundred) clay. With increasing the clay content to 20 phr, both non-exfoliated (stacked layers) and exfoliated structures can be observed simultaneously in the nanocomposites. The results of mechanical tests on the vulcanized clay-free XSBR and XSBR/clay nanocomposites showed that the nanocomposites present better mechanical properties than clay-free XSBR vulcanizate. Furthermore, modulus, tensile strength, tensile strain at break and hardness (shore A) increased with increasing the clay content, indicating the nanoreinforcement effect of clay on the mechanical properties of XSBR/ clay nanocomposites.
New epoxy-ionic liquid dispersions. Room temperature ionic liquid as lubricant of epoxy resin-stainless steel contacts
Authors: Sanes José , Carrión-Vilches Francisco-José , Bermúdez María-Dolores 
Published: August 2014

AbstractRoom-temperature 1-ethyl-3-methylimidazolium tetrafluoroborate ionic liquid (IL) reduces friction and wear of epoxy resin/AISI 316L stainless steel contacts when used as neat external lubricant. In order to study the internal lubricant performance of IL, variable concentration epoxy+IL dispersions containing 0.5-3.3 wt.% IL were obtained by mechanical mixing and casting. SEM cryofracture and EDS show dispersed rounded IL particles within the epoxy matrix. The new dispersions have slightly lower Tg and hardness values than the unmodified resin. Fracture modes and tensile strength are similar for epoxy and epoxy+2.7%IL, although the elongation at break reduces in presence of IL. Pin-on-disc tests show that dry friction coefficients decrease exponentially as the IL proportion increases and wear resistance improves in several orders of magnitude for a critical IL concentration of 2.7 wt.%. Wear mechanisms are discussed on the basis of SEM and AFM observations. The surface modification of the new dispersions gives lower static and dynamic friction coefficients when sliding against steel or polytetrafluoroethylene sheets under mild conditions.
Synthesis of α,ω-bis(3-aminopropyldiethoxylsilane) Poly(tri fluoropropylmethyl)siloxanes
Authors: Shi Zhendong , Wang Xinling 
Published: August 2014

AbstractHigh molecular weight α,ω-bis(3-aminopropyldiethoxylsilane) poly(tri fluoropropylmethyl)siloxanes (APTFPMS) were prepared via a “one-step” process, based on the ring-opening polymerization of 1,3,5-tris(trifluoropropylmethyl) cyclotrisiloxane (F3) in the presence of water and 3-aminopropyltriethoxysilane (APTES). GPC, FT-IR and 1H NMR confirmed the structure of the polymers. It was found that the amount of APTES had significant influence on the reaction rate and the molecular weights of polymers decreased with the increasing amount of water. It was probably because both water and the amino group of APTES favoured generation of hydroxyl ions, which efficiently initiate the polymerization of F3 to achieve APTFPMS. In order to verify this mechanism, another “two-step” process was also performed: Firstly the α,ω-dihydroxylated poly(trifluoropropylmethyl) siloxanes were synthesized from F3 catalyzed by both diaminoethane and water, then reacted with APTES to achieve APTFPMS. All the syntheses had high yields and the molecular weight of the polymers ranged from 2000 to 25000.
Synthesis and characterization of the polyacrylate latex functionalized by fluorine and silicon
Authors: Ding Xiaofeng , Guan Rong , Chen Peizhi 
Published: August 2014

AbstractNovel functionalized polyacrylate latex with fluorine and silicon was prepared by semi-continuous dropping technique. 19F NMR, elemental analysis of the silicon (EAS) and FT-IR measurements prove that 2,2,2-trifluoroethyl methacrylate (TFEMA) and α,ω-bis(hydroxyl)polydimethylsiloxane (PDMSH) is successfully polymerized. TEM demonstrates that the functionalized latex particles were spherical, uniform and stable. Contact angle measurement and surface energy estimation show that the highest water contact of the functionalized latex films were 118.3° and the surface energy was as low as 11.7 mJ/m2. Water absorption ratio measurement reveals that the water resistance of the functionalized latex films is improved. The heat resistance of the functionalized latex films does not show a large difference from that of the original polyacrylate in our investigated systems.
Preparation, Morphology and Thermal Properties of Rubber-Modified Polyester Resins
Authors: Munyati M O , Lovell P A 
Published: August 2014

AbstractThe preparation of polyester resin blends consisting of an unsaturated polyester resin matrix and rubbery particles comprising three radially-alternating glassy and rubbery layers is described. The morphology of the resin blends was examined by transmission electron microscopy (TEM) while thermal properties were investigated by differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA). The results show that the particles were prepared with good control of particle size and morphology. DMTA results showed no reduction in the Tg of the matrix whilst the shear modulus of modified materials was found to be lower than that of the matrix material.
Synthesis of Imidazole End-Capped Poly(n-butyl methacrylate)s via Atom Transfer Radical Polymerization with a new functional initiator containing imidazolium group
Authors: Zhu Aihua , Wang Zhi , Xie Meiran , Zhang Yiqun 
Published: August 2014

AbstractThe synthesis of imidazole end-capped poly(n-butyl methacrylate)s via atom transfer radical polymerization (ATRP) is reported. n-Butyl methacrylate (n- BMA) was polymerized in isopropyl alcohol (IPA) at different temperatures via ATRP using a new N-heterocyclic functional initiator (1-α-bromoisobutylimidazole, BrBI) in the presence of CuBr/2,2’-bipyridine (bpy) as the catalyst. With this new initiating system, a successful ATRP of n-BMA was carried out, and imidazole endcapped polymers with predetermined molecular weights and low polydispersities (1.1<PDI<1.3) were obtained at low polymerization temperature (below 80 °C). Furthermore, the dependence of both the rate of polymerization and PDI on temperature gave the optimal reaction temperature (50 °C). However, at elevated temperature (especially above 80 °C), some different phenomena appeared in the polymerization: the conversion of monomer remains constant after reaching a maximum value (20%-30%), and the higher the temperature, the lower the conversion obtained.
Highly soluble and colorless fluorinated poly(ether imide)s based on 4,4’-(2,5-tolylenedioxy)diphthalic anhydride and trifluoro methyl-substituted aromatic bis(ether amine)s
Authors: Yang Chin-Ping , Hsiao Sheng-Huei , Su Yu-Yang , Lin Chun-Hung , Hsu Mei-Yuan 
Published: August 2014

AbstractA series of novel fluorinated poly(ether imide)s (PEIs) IVa-h were synthesized from 4,4’-(2,5-tolylenedioxy)diphthalic anhydride (I) and various trifluoromethyl-substituted aromatic bis(ether amine)s (IIa-h) via a conventional two-step method with thermal or chemical imidization of the precursor poly(amic acid)s. These PEIs were readily soluble in a variety of organic solvents; they were soluble with a concentration higher than 10% in amide-type polar solvents, ether type solvents, and chlorinated hydrocarbons. The solution-cast films showed a high optical transparency and low color intensity, with an ultraviolet-visible absorption edge of 371- 377 nm and low b* values (a yellowness index) of 4.9-7.5. These films were strong and tough with tensile strength of 90-103 MPa. They exhibited glass-transition temperatures (Tg) in the range of 207-293oC, with 10% weight loss temperature in excess of 500oC in air or nitrogen atmosphere. They also showed low-dielectric constants (2.95-3.37 at 1 MHz) and low moisture absorption (0.20- 0.67 wt %).
Fabrication of cucurbit[6]uril mediated alginate physical hydrogel beads and their application as a drug carriers
Authors: Huang Xiaoling , Tan Yebang , Zhou Qifeng , Wang Yuexia 
Published: August 2014

AbstractA novel cucurbit[6]uril (CB[6]) mediated alginate physical hydrogel bead was prepared for the first time, which is based on the electrostatic attraction and ion-dipole interaction between sodium alginate and CB[6]. These alginate/CB[6] gel beads are useful in controlled drug delivery and other biomedical applications. The potential of alginate/CB[6] gel beads as carrier for 5-Fluorouracil (5-Fu) was studied in this paper. The properties of alginate/CB[6] gel beads were studied by FT-IR, XRD and TGA. The process of the formation of alginate/CB[6] gel beads was recorded by Digital cameras. The external morphology of the dried beads were observed using SEM. Alginate/CB[6] gel beads first was formed as a thin film on the surface of the alginate solution droplet, holding its spherical shape. The color of the alginate/CB[6] gel beads changed from almost colorless to white with the increase of gel time, and also the beads became small and compact. The dried alginate/CB[6] gel beads were about 900-1000 μm, irregular spherical and the surface of dried beads showed a corrugated surface having a uniform distribution of regular nodules and cavities.
Carboxyl functionalized poly(methyl methacrylate-acrylic acid-ethylene glycol dimethacrylate) copolymer particles and their amination with amine-nucleophiles
Authors: Ahmad Hasan , Hossain Md. Emtiaz , Rahman M. Abdur , Rahman M. Mahbubor , Miah M. A. Jalil , Tauer Klaus 
Published: August 2014

AbstractPoly(methyl methacrylate-acrylic acid-ethylene glycol dimethacrylate) copolymer particles abbreviated as P(MMA-AA-EGDM) copolymer particles were prepared by soap-free emulsion copolymerization. The concentration of carboxyl group on/near the surface of particles increased with the increase in acrylic acid (AA) content in the recipe. The carboxyl groups were reacted with amine nucleophiles such ethylene diamine and 1,6-diaminohexane through preactivation with dicyclohexyl carbodiimide as a coupling agent. The modified particles were characterized by electron micrographs and FTIR spectral analysis. Adsorption behaviours of some biomolecules were measured to have idea about=-0 the polarity of the particles surface
Preparation of super HIPS via nanocomposite assemblies in the presence of toughener- intercalant
Authors: Bagcioglu Cuneyt , Sen Sinan , Yagci Yusuf , Nugay Turgut , Nugay Nihan 
Published: August 2014

AbstractHighly toughened super high-impact polystyrene (HIPS)/organophilic montmorillonite (Org-MMT) nanocomposite was prepared by solution blending method. Organophilic modification of MMT layered silicate was achieved by using a special toughener-intercalant, quaternary ammonium salt of α-tertiary amine functionalized polybutadiene and shown by X-ray diffraction analysis. The resulting HIPS/Org-MMT nanocomposite was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), atomic force microscopy (AFM), thermogravimetric analysis (TGA), and static and dynamic mechanical analyses. The morphological study of HIPS/Org-MMT nanocomposite showed that nanolayers were exfoliated in nanocomposite and moreover caused much more well dispersed and reduced PS occluded rubber domains. This mechanism was found to be responsible for dramatic increase in toughness of nanocomposites. Additionally, improved thermal and dynamic mechanical properties of the resultant nanocomposite promises to open a new way for highly toughened super HIPSs via nanocomposite assemblies even with a very low degree of clay loading.
Rapid phthaloylation and succinylation of hemicelluloses by microwave irradiation
Authors: Peng Feng , Ren Jun-Li , Sun Xiao-Feng , Xu Feng , Sun Run-Cang , Peng Bai , Sun Jin-Xia 
Published: August 2014

AbstractRapid phthaloylation and succinylation of wheat straw hemicelluloses with phthaloyl dichloride (PdC) and succinyl chloride (SC) in N,Ndimethylformamide/ lithium chloride (DMF/LiCl) system using N-bromosuccinimide (NBS) as a catalyst was achieved for only 5 minutes at 50 °C by microwave irradiation. The degree of substitution (DS) ranged between 0.43 and 1.47. The effect of the molar ratios of xylose units in hemicelluloses to phthaloyl dichloride or succinyl chloride on the degree of substitution was investigated. It was found that the reactivity of succinyl chloride was higher as compared to Phthaloyl dichloride under similar experimental conditions. 13C NMR studies revealed that the esterification occurred at the C-3 and C-2 positions in the β-D-xylose units of hemicelluloses, but preferentially at C-3 position. However, it should be noted that microwave irradiation did result in more degradation of the macromolecular hemicelluloses than conventional heating technique as shown by a lower thermal stability of the hemicellulosic derivatives obtained by microwave irradiation than those obtained by conventional heating technique.
Electromechanical properties of poly(dimethylsiloxane) and poly(3,4-ethylenedioxy thiophene)/poly(styrene sulfonic acid) blends
Authors: Wichiansee Wijittra , Sirivat Anuvat 
Published: August 2014

AbstractElectromechanical properties of crosslinked polydimethylsiloxane (PDMS) and PDMS_PEDOT/PSS blends were investigated as potential actuator materials. Experiments were carried out under the oscillatory shear mode and with applied electric filed strength varying from 0 to 2 kV/mm. The storage modulus, G', of the crosslinked PDMS increases with increasing electric filed strength with a scaling behavior: ΔG' α Eα where the scaling exponent α is equal to 0.88. With PEDOT/PSS particles added at volume fractions of 5, 10, 15, and 20 vol%, the storage modulus G' of the polymer blends, are higher than that of the pristine crosslinked PDMS. The scaling exponent of the scaling behavior decreases from 0.88 to 0.10 as the volume fraction increases from 0 to 20 vol%. The storage modulus sensitivity,, attains maximum values of 8%, 9%, 10%, and 9%, at particle volume fractions of 5, 10, 15, and 20 vol%, respectively at the electric field strength of 2 kV/mm. Temporal response of the crosslinked PDMS system is irreversible, but the response of the PDMS_PEDOT/PSS system is evidently reversible
Electrospinning of poly-L-lactide nanofibers on liquid reservoir collectors
Authors: Röcker Thorsten , Greiner Andreas 
Published: August 2014

AbstractThe electrospinning process of Poly-L-lactide (PLA) solutions using liquid reservoir collectors was studied. As collector liquids, distilled water and sodium chloride solutions of different concentrations were used. A new, non-linear correlation of the fiber diameter and the filling of the collector was found. It was also proved, that the electrical conductivity of the substrate has a strong influence on the electrospinning process and the nanofibers obtained therein, both in diameter and in morphology
Studies on the structure, morphology and thermal properties of HDPE/ petroleum resin blends
Authors: Wu Chifei , Cao Deming , Cao Yuanyi , Gao Yuanji , Guo Weihong 
Published: August 2014

AbstractThe phase structure, crystallization and melting behavior of high density polyethylene (HDPE) blends with hydrogenated petroleum resin P-100 were investigated by polarized optical microscopy (POM), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). Results of polarized optical microscopy and scanning electron microscopy indicated that the structures of blends had a three-dimensional bi-continuous network. The network sizes depended on the blends composition and crystallization conditions, when the blends were quenched or cooled down slowly below the melting temperature of HDPE from molten state; the network sizes decreased with both the increasing of HDPE content and the decreasing of the quenching temperature. Differential scanning calorimeter analysis revealed that the melting point and crystallization temperature of HDPE in blends shifted to lower temperature with the decreasing of HDPE concentrations. The depression of HDPE melting point and crystallization temperature in blends were attributed to the smaller sizes of HDPE crystallites in presence of petroleum resin. The activation energy values and nucleation activity values indicated HDPE had lower crystallization activation energy and P-100 acted as a more effective nucleating agent only at low HDPE concentration
Synthesis of carboxymethyl-chitosan/acrylic acid hydrogel using silane crosslinker
Authors: Yasin Tariq , Rasool Nadia , Akhter Zareen 
Published: August 2014

AbstractNovel pH sensitive carboxymethyl (CM) chitosan/acrylic acid hydrogels were prepared. CM-chitosan and acrylic acid (AA) in aqueous solution were copolymerized and crosslinked by using vinyltriethoxysilane (VTESi). Different amounts of AA and crosslinker were incorporated in CM-chitosan/AA hydrogel. IR analysis confirmed the presence of pyranose ring as well as Si-O-Si linkage within the hydrogel. Thermogravimetric analysis showed an increase in the stability of hydrogel either having high AA ratio or high crosslinker ratio. The swelling of the hydrogels was carried out by investigating the effect of time, pH (buffered and nonbuffered) and ionic media. In non-buffered media the overall swelling was found to be high as compared to buffered media. Maximum swelling was observed in hydrogel having mass ratio of 7.0 (AA : CM-chitosan). This hydrogel showed low swelling in low pH similar to that of the stomach and high swelling in neutral pH similar to that of the small intestine and can be used in drug delivery applications
Comparison of conventional and controlled bulk polymerization of styrene by N-methyl-2-pyrrolidone and 1-dodecanethiol
Authors: Krajnc Matjaž , Poljanšek Ida , Likozar Blaž 
Published: August 2014

AbstractControlled radical polymerization of styrene was initiated using Nmethyl- 2-pyrrolidone (NM2P) and 1-dodecanethiol (1DT). This polymerization system exhibited “living” characteristics, namely the molecular weight averages of resulting polymers increased linearly with conversion, which has been determined by gel permeation chromatography (GPC) analysis. The polymer was additionally characterized with Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (1H NMR) spectroscopy. Kinetics of controlled radical polymerization has been studied and the temperature dependency of overall polymerization rate constant has been determined. A comparison of conventional bulk radical and controlled bulk radical polymerization of styrene has been explored. Conventional radical polymerization was initiated with 2,2’-azobis(2- methylpropionitrile) (AIBN), whereas 1-dodecanethiol was applied as a chain transfer agent. The reaction rate of controlled radical polymerization was slower than the reaction rate of conventional radical polymerization initiated with AIBN. Consequentially, the activation energy and the pre-exponential factor were lower in the case of controlled polymerization in comparison to the ones observed in the conventional - AIBN initiated - system. Furthermore, by comparing the controlled to the conventional radical polymerization lower polydispersities were observed. Macromolecular structure analysis suggested a more linear chain structure in the controlled radical polymerization system. The thermal properties of polymer products have also been studied and the corresponding glass transition temperatures were higher upon comparison of the conventional and the AIBN initiated system, respectively
Ruthenium(II) Ions triggered direct supramolecular polymerization of bis-terpyridine poly(ethylene glycol): New Insights on synthesis and optimization
Authors: Chiper Manuela , Hoogenboom Richard , Schubert Ulrich S. 
Published: August 2014

AbstractIn order to obtain linear and high molecular weight Ru(II) coordination polymers, we investigated the reaction conditions for the direct one-step metallopolymerization of bis-terpyridine poly(ethylene glycol) 3 with RuCl3 in the presence of reducing agents. Here we discuss the direct synthesis method, the optimization and the purification of the water soluble Ru(II) chain extended poly(ethylene glycol). The optimization of the metallo-polymerization was monitored by SEC. For the highest molecular weight Ru(II) coordination polymer 4 obtained in this study, full characterization was performed by 1H-NMR and UV-Vis spectroscopy as well as SEC proof for the formation and the stability of the designed structure