bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of triethoxy and triphenylvinylsilanes on the porous structure of cross-linked poly(methyl methacrylate) beads
Authors: Naghash Hamid Javaherian , Fariba Dehghan , Ahmad Reza Massah 
Published: August 2014

AbstractNovel microprous beads with the particle size of about 0.6-1.1 mm were prepared for the first time, from methylmethacrylate (MMA), ethyleneglycol dimethacrylate (EGDM), triethoxyvinylsilane (TEVS) and triphenylvinylsilane (TPVS) by suspension polymerization technique. In this study toluene was used as solvent. The swelling measurement results indicate that increasing silicone concentration increases the amount of pores and porosity percent, the weight swelling ratio, and particle sizes, but it has been observed that the apparent density decreases in the case of TEVS, and not in the case of TPVS. Also it has been demonstrated that the volume swelling ratio is independent of TEVS and increases by increasing TPVS concentration. The resulting copolymer beads were characterized by using swelling studies and Fourier transform infrared spectroscopy (FTIR). The morphology of copolymer beads were also investigated by scanning electron microscopy (SEM) and optical microscopy (OM).
Evaluation of mechanical, morphological and thermal properties of waste rubber tire powder/LLDPE blends
Authors: Zhang Zhen Xiu , Zhang Shu Ling , Kim Jin Kuk 
Published: August 2014

AbstractPolymer blends of WRT (waste rubber tire) powder/LLDPE (linear low density polyethylene) have been attempted to prepare thermoplastic elastomers (TPEs). The effects of maleic anhydride-grafted styrene-ethylene-butylene-styrene (SEBS-g-MA) and dicumyl peroxide (DCP) on mechanical, morphological and thermal properties of the blends were evaluated using universal testing machine (UTM), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermogravimetric analyses (TGA). It was found that combination of SEBS-g-MA and DCP could better enhance the mechanical properties of WRT powder/LLDPE blends compared to SEBS-g-MA or DCP alone. Better compatibility between WRT powder and LLDPE was responsible for the enhancement of mechanical properties, as supported by SEM. The incorporation of SEBS-g-MA and DCP with WRT powder/LLDPE blends reduced the crystallizable perfectness of the blends, but slightly increased the thermal stability of the blends, as shown from DSC and TGA results
Synthesis of soluble sulfonated polybenzimidazoles derived from 2-sulfonate terephthalic acid
Authors: Wu Qunying , Xiao Guyu , Yan Deyue 
Published: August 2014

Abstract2-Sulfonate p-terephthalic acid (sTA) was synthesized, and sulfonated polybenzimidazoles (sPBI) were prepared by direct polycondensation of 3,3’- diaminobenzidine (DAB) and sTA with 4,4’-oxybis(benzoic acid) (OBBA) or 2,2’- bis(4-carboxylphenyl)-hexafluoropropane (BCHFP). Thus the ether groups and hexafluoroisopropylidene units were incorporated into the backbone of the sPBI in order to improve the flexibility and solubility. The sPBI based on OBBA showed poor solubility, while the sPBI containing hexafluoroisopropylidene units were soluble in common solvents. sPBI-20 ~ sPBI-60 could form tough and transparent membranes by solution casting. sPBI indicated high thermal stability, the 5% weight loss temperature (T5%) which was higher than 520°C, decreased with the increase of degree of sulfonation. sPBI-20 ~ sPBI-60 showed no glass transition at temperatures lower than 380°C. In addition, sPBI showed low water uptake, low swelling ratio as well as excellent resistance to oxidation. But sPBI exhibited low proton conductivity because of the strong acid-base interactions between basic benzimidazole and sulfonic acid groups.
Anti-reflection and anti-static (AR/AS) coatings made by TiO2 sol-gel process with poly(3,4-ethylenedioxy thiophene)
Authors: Kim Won Jung , Kim Tae Young , Park Chin Su , Kim Jong Eun , Lee Tae Hee , Yoon Ho Gyu , Suh Kwnag S. 
Published: August 2014

AbstractIn this study, we designed a two-layer hybrid Anti-Reflection/Anti-Static (AR/AS) thin film. Two kinds of UV-curable fluorinated compounds were synthesized as low refractive index materials, and a TiO2 sol combined with a conducting polymer, poly(3,4-ethylenedioxythiophene) was made by the sol-gel process for use as a high refractive index material as well as a conducting layer. In order to determine the most optimized AR/AS system, the spectral properties were simulated with the refractive index of each layer. According to the simulated results, a high refractive index layer was deposited on the hard coated poly(ethylene terephthalate) (PET) substrate by the spin coating technique, and a low refractive index layer was spin coated on the low refractive index layer. The reflectance and transmittance were measured by UV-VIS-NIR spectroscopy. It was found that the measured reflectance and the maximum transmittance of the AR/AS film were 0.71 %R at a wavelength of 550 nm and 93 %T in the wavelength range between 400 and 700 nm, respectively. The surface resistance of the AR/AS film was 108.6 ohms.
Crystalline form transformation of isotactic polypropylene induced by N,N’-diphenyl glutaramide
Authors: Lu Quliang , Dou Qiang 
Published: August 2014

AbstractN,N’-Diphenyl glutaramide (DPG) is found to be an effective nucleating agent to induce the β-form of iPP. The results of wide angle X-ray diffraction, differential scanning calorimetry and polarized light microscopy indicate that 0.2 wt% of DPG can induce the maximum amount of β-form iPP, and the favorable crystallization temperature for the growth of β-form is 120 ˚C in this study. Analysis of the misfit factor between the cell parameters of DPG and β-iPP shows β-iPP can epitaxially crystallize on the bc face of DPG crystal well.
Electrical conduction of polyimide films prepared from polyamic acid (PAA) and pre-imidized polyimide (PI) solution
Authors: Kim T.Y. , Kim W.J. , Lee T.H. , Kim J.E. , Yoon H. G. , Suh K.S. 
Published: August 2014

AbstractElectrical conduction characteristics in two different polyimide films prepared by the imidization of polyamic acid (PAA) and pre-imidized polyimide (PI) solution were investigated. It is found that the current density of the polyimide film from PAA was higher than that of the polyimide film from PI at the same electric field, even though the conduction mechanism in both polyimide films follows the ionic hopping model. The hopping distance was calculated to be 2.8 nm for PAA type and 3.2 nm for PI type polyimide film. It is also found that the decay rate of the residual electrostatic charges on the polyimide films becomes faster in the PAA type than in the PI type polyimide film.
Anomalous phase behavior in blends of -SO3H terminated polystyrene with poly(n-butyl acrylate) containing a small amount of tertiary amino groups
Authors: Yamamoto Kenji , Nanakno Ayumi , Masunaga Hiroyasu , Akiba Isamu 
Published: August 2014

Abstract Phase behavior in the blend of -SO3H terminated polystyrene (PSS) with poly(n-butyl acrylate-co-N,N-dimethylaminoethyl methacrylate) containing 6.0 mol% N,N-dimethylaminoethyl methacrylate (P1) is investigated by optical microscopy and small-angle X-ray scattering (SAXS). Comparing the miscibility of polystyrene/P1 blend, it is confirmed that the miscibility of the PSS/P1 blend is drastically improved by the hydrogen bonds between -SO3H and tertiary amino group. In addition, two-phase region of the PSS/P1 blend is split into two regions around the stoichiometric composition, in which the molar ratio of -SO3H to tertiary amino group is 1:1 stoichiometry. SAXS result shows that the PSS/P1 blend at stoichiometric composition forms a block copolymer-like aggregate and it takes a disorder state.
Preparation and Characterization of Novel Sulfonated Copolyimide Membranes
Authors: Mehdipour-Ataei Shahram , Banihashemi Ahmad , Yeganeh Hamid , Rabiee Ahmad 
Published: August 2014

AbstractNucleophilic substitution reaction of 5-amino-1-naphthol with disodium- 3,3'-disulfonate-4,4'-dichlorodiphenylsulfone (SBCPS) in the presence of sodium hydroxide and subsequent acidification resulted in a new diamine monomer named as 3,3'-disulfonic acid-bis[4-(5-amino-1-naphthoxy)phenyl]sulfone (DANPS). This monomer containing ether, sulfone, and bulky naphthyl groups was used to prepare two series of new copolyimides via one step polycondensation reaction. This sulfonated diamine (DANPS) was polycondensed with two unsulfonated diamines, 4,4'-oxydianiline (ODA), and m-phenylenediamine (m-PDA) and 1,4,5,8- naphthalene tetracarboxylic dianhydride (NDA) to prepare copolyimides with controlled degrees of sulfonation. Monomers and polymers were fully characterized with common methods and the physical properties of the polymers including thermal behavior and stability, viscosity, and ion exchange capacity (IEC) as a criterion for evaluation of the performance in fuel cell membrane were investigated.
A simple route to high-strength hydrogel with an interpenetrating polymer network
Authors: Tang Qunwei , Sun Xiaoming , Li Qinghua , Wu Jihuai , Lin Jianming , Huang Miaoliang 
Published: August 2014

AbstractHydrogels have potential applications in many fields, but the poor mechanical strength has limited their further development. In this article, we designed a simple route to high-strength interpenetrating polymer network (IPN) hydrogel from polyacrylamide (PAAm) and poly(vinyl alcohol) (PVOH). The highest tensile strength and elongation were 2.4 Mpa and 4300 %, respectively. It was found that the hydrogel strength depended on the chemical crosslinking, physical entanglement and PVOH precipitates. Because of the hydrogen bonding interactions and self-crosslinking, the structure of PVOH transferred from crystal to amorphous. PVOH precipitates scattered in the crosslinked PAAm matrix which dispersed the stress and improved the hydrogel toughness. The simple method is versatile in synthesizing high-strength IPN hydrogels using many kinds of polymer species.
Cryogenic mechanical milling of high density polyethylene
Authors: Cysne Barbosa Ana Paula , Stranz Michael , Katzenberg Frank , Köster Uwe 
Published: August 2014

AbstractHDPE was analyzed after being submitted to cryogenic mechanical milling (CMM) by X-ray diffraction (WAXS), polarized light microscopy and differential scanning calorimetry (DSC). After CMM, besides the known phase transformation of the orthorhombic PE crystals into the monoclinic modification, slight changes in the melting and crystallization behavior as well as an unexpected increase in crystallinity were observed. The observed results can be explained by assuming a solid/solid phase transition as the responsible mechanism.
Positive temperature coefficient effects of carbon blackfilled polytetrafluoroethylene composites
Authors: Zhou Dongxiang , Wang Fajun , Gong Shuping 
Published: August 2014

AbstractCarbon black (CB)-filled polytetrafluoroethylene (PTFE) composites were prepared by compact molding of a dry-mixture of CB and polymer powders followed by a sintering technology. The composites show a very low percolation threshold about 5 vol. %, which can be attributed to the segregated distribution of CB in the interfacial regions of PTFE particles. The PTFE/CB composites exhibit a high PTC transition temperature (>300 0C), high PTC intensity (3.5) and no NTC effects. The absence of NTC effect of the composites was attributed to the extremely high viscosity of PTFE at temperatures above its melting point, which restricts the migration of CB particles and prevents the formation of new conductive networks.
Evaluation of morphological architecture of cellulose chains in grass during conversion from macro to nano dimensions
Authors: Pandey Jitendra K. , Kim Chung-Soo , Chu Won-Shik , Lee Caroline S. , Jang Dong-Young , Ahn Sung-Hoon 
Published: August 2014

AbstractThe cellulose nanowhiskers (CNW) are of imminent importance in the development of ecofriendly green material for environment. Morphological study of their structure was carried out after extraction from grass. The controlled alkali and acid hydrolysis after soxhlet extraction of bleached fiber in ethanol and water provided a mixture of micro/nano fiber which can be further converted into CNW by mechanical treatment. Width of obtained CNW were found to be ~10-65 nm with length of several nanometers as evidenced by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The changes in dimensions during alkali treatment, bleaching and acid hydrolysis of grass exhibited an interesting architecture and clarify the phenomenon of separation of nano level fibrils from the matrix of hemicellulose and lignin which starts after swelling of fibers and opening from middle followed by splitting from each other. The nanofibers were embedded in the matrix surrounded by amorphous layers. The size of fibers was directly associated with the extent of treatments. The crystalline part of fiber was intact during hydrolysis which must be attributed to easy removal of amorphous region by penetration of hydronum ions from acid. The results of SEM and TEM were correlated with the Scanning Ion Microscopy (SIM) which showed a direct evidence of breaking of thick fiber strands resulting in the formation of sharp edged crystalline entities composed of cellulose crystals.
PA6/NBR blends: improvement of processability and mechanical properties
Authors: Gomes Ana C. O. , Soares Bluma G. , Oliveira Marcia G. , Oliveira Marcelo F. L. , Paranhos Caio M. 
Published: August 2014

AbstractThis work deals with the study of the processability of blends based on PA6 and NBR. The aim is to achieve reduced PA 6 melting temperatures in order to avoid degradation of the NBR phase during processing. The effect of different additives in PA has been studied. For this purpose PA6 was blended with nonylphenol, EVA 18, EVA 33 and EVAMA. Among several masterbatches based on PA6; the sample containing 5% of EVAMA presented the best combination of processability and mechanical properties. The influence of additives in the processing behavior, crystallinity of the PA6 phase, mechanical and physicochemical properties are discussed in the present work.
Preparation and characterization of new thermally stable and optically active polyesters by direct polycondensation reaction promoted by Vilsmeier adduct
Authors: Mallakpour Shadpour , Tirgir Farhang 
Published: August 2014

AbstractHighly soluble and optically active aromatic polyesters (PE)s containing phthalimide and flexible chiral groups were prepared with moderate molecular weights by step-growth polymerization of diacid monomer containing pendant 4- [(2L)-phthalimidylpropanoylamino)benzoyl group with several aromatic diols, in a system of tosyl chloride, pyridine (Py) and N,N-dimethylformamide (DMF) to give a series of new optically active PEs with good yield and moderate inherent viscosity ranging from 0.28 to 0.48 dL/g. The aim of this work was to obtain novel optically active PEs that was more soluble in common organic solvents while maintaining the high thermal stability. All polymers derived from such a diacid and aromatic diols were highly organosoluble in solvents like N-methyl-2-pyrrolidinone, N,Ndimethylacetamide, DMF, Py, dimethyl sulfoxide. Thermogravimetric analysis data showed that these PEs are thermally stable, with 10% weight loss being recorded above 400 °C and showed good thermal stability associated with high glasstransition temperatures above 200 °C as measured by differential scanning calorimetry. All of the above polymers were characterized by FT-IR and specific rotation techniques and some of them were also characterized by 1H-NMR and elemental analyses methods.
Compatibility and interactions in polyacrylonitrile/soy protein isolate/polyurethane blends
Authors: Xiao Ru , Yin Duan , Fan Wei , Sun Gang 
Published: August 2014

AbstractPolyacrylonitrile/Soy protein isolate/polyurethane (PAN/SPI/PU) blends were prepared in dimethylsulfoxide (DMSO). The compatibility and interactive properties of PAN/SPI, SPI/PU, and PAN/PU blend systems were studied using dilute solution viscometry and phase contrast microscopy. It was found that PAN/SPI and PAN/PU were immiscible systems, but that there was an attractive interaction between them. However, the SPI/PU was an almost miscible system. To improve compatibility, the main product of graft copolymerization of acrylonitrile and SPI (AN-g-SPI) and the alkaline hydrolysis polyacrylonitrile (HPAN) were used as compatibilizers. The results showed that the mechanical properties of both the PAN/SPI and PAN/SPI/PU systems were significantly improved.
Electrospinning of polyaniline-polyacrylonitrile blend nanofibers
Authors: Raeesi Fatemeh , Nouri Mahdi , Haghi Akbar Khodaparast 
Published: August 2014

AbstractElectrospinning of emeraldine base polyaniline/polyacrylonitrile (PANI/PAN) blends with different composition ratios were performed using Nmethyl- 2-pyrrolidone (NMP) as solvent. The blends were electrospun at various electrospinning temperature and electric fields. Morphology and fibers diameters were investigated by scanning electronic microscopy (SEM). The average diameter of nanofibers and their distributions were determined from 100 measurements of the random fibers with image analyzer software (manual microstructure distance measurement). Electrical conductivity of the prepared mats was characterized using standard four point probe method. The fibers with diameter ranging from 60 to 600 nm were obtained. The PANI/PAN blends containing up to the PANI content of 30% could be electrospun into the continuous fibrous structure, although pure PANI solution was not able to be electrospun into the fibrous structure. Average of fiber diameter decreased with increasing PANI content and electrospinning temperature. The electrospun PANI/PAN fibers at 50 °C and 75 °C showed smaller diameters with much better uniformity than those electrospun at 25 °C. The electrical conductivity of the mats increased with the increase of PANI content in the blend with percolation threshold of 0.5%.
Chain mobility in bulky carbosilane modified polymeric siloxane systems
Authors: Kowalewska Anna , Delczyk Bogumiła , Chruściel Jerzy 
Published: August 2014

AbstractHydrosilylation of bulky carbosilanes [CH2=CHRC(SiMe2R')3, R=CH2, (CH2)3 or SiMe2; R'=Me or Ph] with oligosiloxane precursors [M(D2DH)7D2M, M(D2DH 2)11D2M, PDMSx%-PMHS100-x% (x=85, 50, 30, 0)] was carried out. The relationship between the mobility of siloxane chain and the type of carbosilane moiety, as well as the type of distribution of carbosilane group along the polymer chain, was consecutively studied. Carbosilane substituents, due to their exceptional steric requirements, have been shown to strongly affect thermal properties of siloxane oligomers, implying a substantial change of the chain flexibility and free volume of modified oligomers.
Effect of boric acid on thermal stability of poly (acrylonitrile-methyl acrylate)
Authors: Han Na , Zhang Xingxiang 
Published: August 2014

AbstractA series of acrylonitrile(AN)-methyl acrylate (MA) copolymers (AN/MA) with molar ratios of 100/0-70/30 were synthesized by water depositing polymerization. One to three percent of boric acid (BA) was adopted as a stabilizer to enhance the thermal stability of AN/MA. The copolymers and the mixtures of copolymers treated with BA were characterized by using Fourier Transform Infrared Spectroscopy (FTIR), Nuclear Magnetic Resonance (1H NMR), Gel Permeation Chromatography (GPC), Differential Scanning Calorimetry (DSC), Thermogravimetry (TG), X-ray diffraction (XRD) and Optic Microscope. The results show that melting point (Tm), glass transition temperature (Tg) and crystallinity of the copolymer decreased while decomposition temperature (Td) increased with the increase of MA content. Tm of AN/MA dropped to 174 °C and Td rose up to 321 °C when 15 mol% MA was incorporated. It was worthy to note that Tm of the copolymers increased conspicuously after being treated with BA. Stability of AN/MA with a molar ratio of 85/15 containing 1 wt% BA improved remarkably. The mixture can be kept stable up to 30 min at 220 °C.
Preparation, characterization and properties of polymeric nanocomposites based on natural rubber and polybutadiene rubber blend
Authors: Kooshki Mehdi Mehrabi , Arani Azam Jalali 
Published: August 2014

AbstractNanocomposites based on natural rubber and polybutadiene rubber blend were prepared by employing different amounts of modified layered silicate. X-ray diffraction was used to determine the structure of prepared nanocomposites. The effects of incorporation of organically modified clays on vulcanization reactions of the rubber blend were analyzed by using oscillating disk rheometer. High reduction in scorch time and optimum cure time was observed when organoclay was added and this was attributed to the amine groups of the organic modifier. Tensile strength, modulus, abrasion resistance and tear strength improved significantly on adding organoclay and there was a good correlation between abrasion resistance and tear strength of the nanocomposites. Elongation at break decreased by using organoclay and increase in loading of organoclay up to 10 phr and further led to decrease in the rate of variation of tensile properties. Thermal stability of the blend was improved by using 5 phr organoclay.
Chitosan-poly(vinyl alcohol) blend nanofibers: Morphology, biological and antimicrobial properties
Authors: Gholipour. K A. , Bahrami S .H. , Nouri M. 
Published: August 2014

AbstractBlend nanofibers from Chitosan (Cs) (Mw =1 X 106) in 2% acetic acid and poly(vinyl alcohol) (PVA) (Mw=72 X 103) in deionized water were produced in 10/90, 20/80, 25/75, 50/50 mass ratio of Cs/PVA. The effect of blend ratio on the fiber formation and fiber properties has been investigated. Nanofibers produced were characterized by SEM, FTIR and DSC. The diameter of fibers increased with increasing chitosan content in blends. However, fibers with lower diameter showed micro cracks on the surface. FTIR data show that these two polymers have intermolecular interaction. DSC data reveals that the exothermic peak at about 200 0C for PVA decreased to lower temperature with increasing Cs content. Chitosan (Cs) (Mw =1 X 106) was hydrolyzed and the molecular weight reduced to 6.219 X 105 then we could electrospin the pure chitosan in 90% acetic acid as solvent and the nanofibers with diameter in the range of 43 nm were produced. SEM results showed that although the chitosan nanofibers were produced, because of high viscosity of solution there are a lot of beads on their surface.The cell culture result show excellent cell viability in this medium when the cells were exposed to chitosan/PVA nanofibers for 7 days in CO2 incubator, 99% RH and 37 °C. On the other hand the chitosan/PVA nanofibers in their antimicrobial experimentations showed efficient antimicrobial properties.
Swelling and network parameters of crosslinked porous octadecyl acrylate copolymers as oil spill sorbers
Authors: Abdel-Azim Abdel-Azim A. , Abdul-Raheim A. Mahmoud , Atta Ayman Mohamady , Brostow Witold , Datashvili Tea 
Published: August 2014

AbstractIn previous work crosslinked copolymers were prepared from cinnamoyloxy ethyl methacrylate (CEMA) and several monomers feed ratios of octadecyl acrylate (ODA). Networks so produced are both flexible and porous; we now report their swelling efficacies as a function of temperature in toluene and in crude petroleum. Network characteristics is presented including the polymer + solvent interaction parameter χ, effective crosslink density υe, equilibrium modulus of elasticity E, average molecular weight between crosslinks Mc and the theoretical crosslink density υt. These parameters are correlated with structures of the synthesized sorbers.