bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation of vinyl polymer/polyurethane hybrid latex particles and their application in nano-sized vinyl polymer particle/thermoplastic polyurethane blends
Authors: Wei Yanyan , Zong Chengzhong , Wang Fufang 
Published: August 2014

AbstractVinyl polymer/polyurethane hybrid latex particles with various compositions were successfully prepared via emulsion polymerization of vinyl monomer in the presence of self-emulsified polyurethane dispersion without using any surfactant. Studies were carried out on polymerization kinetics, characterization of the hybrid particles and the physical properties of nano-sized vinyl polymer particle/thermoplastic polyurethane blends. It was found that the maximum content of vinyl polymer in polyurethane hybrid particles was up to 80 percent and all of the vinyl polymer/polyurethane hybrid particles were less than 120 nm. Infrared spectroscopy, thermal gravimetric analysis and differential scanning calorimetry analysis indicated the influence of vinyl polymer on the polyurethane hybrid particles. With the polyurethane shells outside and, therefore, good compatibility with polyurethane matrix, the hybrid particles can be easily blended into polyurethane matrix. Some unusual changes of dynamic mechanical properties in the low temperature region were found in the blends of hybrid particles and thermoplastic polyurethane. With the addition of only 3%, the mechanical properties of these blends did not show a significant change. This study provided a new method to prepare hybrid particles in the absence of surfactant and made an attempt on application of vinyl polymer/polyurethane hybrid particles in the blending modification
Preparation of core-shell polymeric nanocapsules containing liquid cores via redox interfacial-initiated microemulsion polymerization
Authors: Weijun Liu 
Published: August 2014

AbstractIn this work, polystyrene (PSt) nanocapsules were successfully prepared by one-stage redox Interfacial-initiated inversed micro-emulsion polymerization of styrene (St), the cumene hydroperoxide (CHPO) and tetraethylenepentamine (TEPA) as the redox initiation pairs. The water-soluble TEPA acted as the reducing component and the oil-soluble CHPO as the oxidant component of the redox initiation system. The primary radicals were produced mainly at the oil/water interface to initiate the polymerization of styrene (St). Core-shell polymeric PSt nanocapsules were obtained by one-stage polymerization via this method, which was supported by the techniques of transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM). The particle size and polydispersity index (PDI) of nanocapsules were determined by dynamic light scattering (DLS). The results demonstrated that interfacial-initiated inversed microemulsion polymerization to form core-shell nanocapsules containing liquid cores by one-stage is successful.
Preparation of the crosslinked polymer electrolyte membranes based on a hyperbranched poly(amidoamine) and their proton conductivity
Authors: Zhang Yongwen , Huang Wei , Zhou Yongfeng , Yan Deyue 
Published: August 2014

AbstractA series of novel crosslinked polymer electrolyte membranes were successfully prepared based on the modification of a hyperbranched poly(amidoamine) with terminal vinyl groups. The membranes possessed the different contents of proton-generating sites (i.e., protonated tertiary amine groups) and triflate (Tf2N-) in the crosslinked network. They showed good mechanical and thermal stability. The water uptakes of them were ca. 8.4-24.5%. Their proton conductivity was of the order of ca. 10-5-10-2 S/cm in the range of 30-80 °C, and the proton conductivity increased with improving the protonation ratio. AFM results disclosed the micro-phase separation of the hydrophilic proton-generating sites and the hydrophobic domains of Tf2N- ions. The resulting locally continuous hydrophilic clusters could provide proton transport channels to produce the high proton conductivity. This kind of polymer electrolyte membranes may have potential applications in PEFCs and other electrochemical fields.
Enhanced impact strength and deviated thermal decomposition of PP and PS toughened with graft-modified rubbers
Authors: Liu Hongtao , Zuo Danying , Liu Heng , Li Linzhou , Li Jianlin , Xu Weilin 
Published: August 2014

AbstractGraft-modified rubbers including maleic anhydride grafted ethylene propylene diene monomer (MAH-g-EPDM) and 49% methyl methacrylate grafted natural rubber (MMA-g-NR, i.e. MG49 rubber) were employed to toughen polypropylene (PP) and polystyrene (PS). The results showed that Charpy impact strength of the notched PP specimens and unnotched PS specimens at room temperature was improved markedly by addition of the graft-modified rubbers. Moreover, Charpy impact strength of the plastics increased with increasing graftmodified rubbers content and the incorporation of MAH-g-EPDM enhanced impact strength of the plastics more markedly than MG49. The result of thermogravimetric analysis (TGA) indicated that the addition of MAH-g-EPDM improved the thermal stability of PP, while the incorporation of MG49 reduced it. Good compatibility between the plastics and MAH-g-EPDM and saturation of EPDM could be responsible for these mechanical and thermal features. This preliminary work may also provide some information for oil-resistant modification of plastics due to the polar groups grafted onto the backbone of rubbers.
Improvement of thermal properties of polyhydroxybutyrate by grafted chemicals
Authors: Hong Shinn-Gwo , Lin Chia-Hau 
Published: August 2014

AbstractThe crystallization and thermal degradation behaviors of polyhydroxybutyrate (PHB) grafted with maleic acid (MAc) and exo-3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride (ETA) are analyzed with differential scanning calorimetry (DSC), dynamic thermogravimetric analysis (TGA), and gel permeation chromatography (GPC). It is obtained that the PHB grafted with MAc or ETA has a faster crystallization rate, larger crystallinity, and better thermal stability than the as-received PHB. The thermal stability of specimens are in the order of the as-received PHB < PHB grafted with ETA < PHB grafted with MAc. The grafting ratio of MAc is larger than that of ETA. The thermal stability of PHB can be greatly improved by grafting a small amount of MAc. The activation energy of the PHB degradation reaction are little affected by the grafted chemicals, nonetheless, the reaction order and frequency factor are significantly affected by the grafted MAc.
Studies on the properties and the thermal decomposition kinetics of natural rubber prepared with calcium chloride
Authors: Li Cheng-peng , Zhong Jie-ping , Yang Lei , Li Si-dong , Kong Ling-xue , Hou Ting-ting 
Published: August 2014

AbstractTo evaluate calcium chloride coagulation technology, two kinds of raw natural rubber samples were produced by calcium chloride and acetic acid respectively. Plasticity retention index (PRI), thermal degradation process, thermal degradation kinetics and differential thermal analysis of two samples were studied. Furthermore, thermal degradation activation energy, pre-exponential factor and rate constant were calculated. The results show that natural rubber produced by calcium chloride possesses good mechanical property and poor thermo-stability in comparison to natural rubber produced by acetic acid.
The preparation of phosphorylcholine-containing poly(Llactide) nanoparticles with solvent evaporation method
Authors: Cao Jun , Chen Yuanwei , Chen Niancao , Luo Xianglin 
Published: August 2014

AbstractPhosphorylcholine-containing poly(L-lactide) (PLLA-PC) is a kind of amphiphilic copolymer synthesized with L-lactide (LLA) as monomer and glycerophosphorylcholine as ring-opening reagent. In this paper, self-assembly nanoparticles of PLLA-PC were prepared with solvent evaporation method. The factors that affected the properties and stability of nanoparticles were investigated. Transmission electron microscope (TEM) indicated that PLLA-PC nanoparticles presented typical core/shell structure. The critical micelle concentration (CMC) was determined with fluorescent probe method. The results showed that the CMCs were quite low (< 1×10-3 g/l) and were dependent on LLA units in the copolymer. The size of the nanoparticles was detected by dynamic light scattering (DLS). The results indicated that the size could be affected by LLA units, the amount of solvent and water in the preparation process. On the other hand, the obtained nanoparticles were stable while being stored at 4 °C, and hardly changed over the dilution with water, which was of great importance in venous injection. The solubility of clofazimine was better in aqueous solution of PLLA-PC nanoparticles than in pure water. This preliminary study suggested that PLLA-PC nanoparticles had a great potential as delivery system for hydrophobic drug.
Property of poly(hydroxybutyrate) complexed polymer with soy protein isolate using glycerol as a medium
Authors: Ma, Xiaolu , Cheng Guoxiang 
Published: August 2014

AbstractA kind of poly(hydroxybutyrate) complexed polymer with soy protein isolate (PcSg) was prepared using glycerol as a medium. Effect of content of SPI on thermal, mechanical properties and water absorption of the PcSg polymer was investigated. The results indicated that SPI not only is miscible with PHB, but also may improve tenacity. The PcSg polymer displayed single glass transition ranges on their differential scanning calorimetry (DSC) curves. The fracture stress and Yang’s modulus of the PcSg increased with PHB concentration, but fracture elongation declined. Water absorption of the PcSg was estimated by water absorption rate of the polymers. By the ratio of hydrophobic PHB and hydrophilic SPI, water absorption of the PcSg was efficaciously modified. It was proposed that the effect on the PcSg mainly was because of intermolecular interactions between PHB and SPI.
Study on the aqueous two-phase copolymerization of cationic polyacrylamide
Authors: Wu Yu-min , Liu Yue-tao , Xu Jun , Zhang Na-na 
Published: August 2014

AbstractAqueous two-phase copolymerization of acrylamide (AM) and dimethylaminoethyl methacrylate methyl chloride (DMMC) was carried out in polyethylene glycol 20000 (PEG 20000) aqueous solution and with 2,2'-azobis(2- amidinopropane) dihydrochloride (V-50) as the initiator. The effects of the temperature, the PEG 20000 concentration, the DMMC/AM molar ratio and the V- 50 concentration on the initial monomer copolymerization rate (Rp), the total monomers conversion and the molecular weight of copolymers were systematically investigated. The initial copolymerization rate increased with an increase of temperature and V-50 content, contrary to the concentration of the PEG 20000 and DMMC. The molecular weight of the copolymers decreased with increasing the reaction parameters above mentioned. The apparent copolymerization activation energy of the system was calculated to be 65.7 kJ·mol-1 according to Arrhenius equation. The optimal PEG 20000 content of the system was 15%~25% (based on the raw materials). The relationship between the initial copolymerization rate (Rp) and the initiator concentration was discussed, and the kinetics equation was Rp~ [I]0.94.
Weld line behaviour of exfoliated and toughened polypropylene layered silica nanocomposites
Authors: Şen Sinan , Ersoy Osman G. , Nugay Turgut , Nugay Nihan 
Published: August 2014

AbstractExfoliated and toughened polypropylene nanocomposites prepared by an introduction of a rubber in the form of compatibilizer toughener: ethylene propylene diene based rubber grafted with maleic anhydride (EPDM-g-MAH) were studied in terms of weld line properties and morphology. Effects of addition of rubber and nanolayer on weld line strength under tensile loading condition of polypropylene matrix were investigated. Data showed that in the absence of either EPDM or nanolayers, a sharp decrease in weld line strength cannot be avoided whereas in the presence of each in optimum ratio, the drastic increase in both toughness and weld line strength values can be easily reached. The beneficial effect is believed to come from the selective placing of nanolayers around the rubber droplets and making them smaller in size which contributes to diffused weld line regions with high mechanical strength.
Novel D-glucose and D-mannose based oligomers: synthesis and characterization
Authors: Pană Ana-Maria , Rusnac Lucian-Mircea , Bandur Geza , Silion Mihaela , Deleanu Călin , Bălan Mihaela 
Published: August 2014

AbstractThis paper presents the synthesis and characterization of two oligomers based on monosaccharides (D-glucose and D-mannose). The oligomers were obtained by the polycondensation of two diacids derived from monosaccharides (3- O-benzyl-5,6-(bis(maleyloxy))-1,2-O-isopropylideneglucofuranose and 1-O-benzyl- 5,6-(bis(maleyloxy))-2,3-O-isopropylidenemannofuranose, respectively), with propane-1,3-diol in the presence of p-toluenesulfonic acid. The oligomers were characterized using FTIR and NMR spectroscopy, HPLC-MS and DSC. The copolymerization of the oligomers with 2-hydroxy-propyl acrylate was studied by DSC to evaluate the possibility of obtaining cross-linked copolymers.
Polystyrene latex particles obtained by emulsifier-free emulsion polymerization and their interaction with bentonite
Authors: Bujanca Ioneta Codrina , Corobea Mihai Cosmin , Miculescu Florin , Dimonie Mihai 
Published: August 2014

AbstractPolystyrene latex particles were prepared by using an emulsifier-free emulsion polymerization with two ionic initiators: potassium persulfate (KPS) and 2,2’-azobis(2-amidinopropane)dihydrochloride (AIBA). The purpose of this study was to obtain polystyrene latex with a good stability in time, a high surface charge density and a small particle size (between 100 and 1000 nm). We used two distinctive molar concentrations for both initiators: 5.5 mM and 55 mM based on aqueous phase. The analysis showed that in the case of KPS initiator the latexes stability was better. With AIBA as initiator smaller latex particles can be achieved. A high surface charge density was measured for large initiator concentration. We achieved satisfying results with both initiators, the optimal condition of polymerization depending on the subsequent utilization of the latex. The SEM images showed that latexes containing bentonite and latexes with no clay have similar size.
Magnetorheological behaviour of magnetic carrageenan gels against shear and compression strains
Authors: Negami Keisuke , Mitsumata Tetsu 
Published: August 2014

AbstractMagnetic field effect on the elasticity was investigated for magnetic carrageenan gel when a shear and compressional deformation was applied to the gel. The magnetic carrageenan gel consists of carrageenan of a polysaccharide, and carbonyl iron particles. The dynamic viscoelastic measurement with shear strain revealed that the storage shear modulus of the gel increased from 1.0×104 to 2.3×106 Pa by applying a magnetic field of 320 mT. On the other hand, the compression measurement showed that the Young’s modulus increased from 6.2×104 to 5.9×105 Pa. The relative changes in the modulus with respect to the original modulus were 230 for shear strain and 9.5 for compressional strain, respectively. This strongly indicates that the magnetic field effect on viscoelasticity strongly depends on the geometry of directions of magnetic field and strain. The effect of vibration suppression of the present gel tuned by magnetic field is also presented.
Controlled RAFT synthesis of polystyrene-b-poly(acrylic acid)-b-polystyrene block copolymers and their self-assembly in an ionic liquid [BMIM][PF6]
Authors: Zheng Linping , Chai Yun , Liu Yang , Zhang Puyu 
Published: August 2014

AbstractThe block copolymer of polystyrene-block-polyacrylate-blockpolystyrene (PSt-PAA-PSt) has been synthesized by reversible addition fragmentation chain-transfer (RAFT) polymerization using S,S′-Bis(α,α′-dimethyl-α′′-acetic acid)-trithiocarbonate (BDATC) as chain transfer agent. Three copolymers form micelles in an ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]). The nanostructures of the PSt-PAA-PSt micelles formed in ionic liquid were observed by transmission electron microscopy (TEM). The self-assembled morphologies of the micelles are strongly dependent on the length of PAA block chains when the chain length of PS is fixed. The affinity of PAA chains for water and [BMIM][PF6] reverses with increasing temperature. Research results show that the copolymer with low polydispersity can be obtained by controlling polymerization, and the flexibility of amphiphilic block copolymers for controlling nanostructure in an ionic liquid presents potential applications in many arenas.
A Raman study of nylon 6 annealed under high pressure
Authors: Xu Weijie , Cao Dahu , Yu Qiang 
Published: August 2014

AbstractUsing a cubic-anvil high pressure apparatus, nylon 6 samples were annealed under 400 MPa to 1.5 GPa. The structure changes of nylon 6 are studied by the methods of wide-angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC) and Raman spectra. Compared with sample prepared at ambient pressure, high pressure treatment makes the hydrogen-bonded sheets pack more closely and thus enhanced CH2 vibration out of the hydrogen-bonded sheets. After high pressure treatment, it is observed that all changes of C-C related vibration modes in nylon 6 are similar with ones in nylon series when the CH2 sequence number increased, from which it is deduced that high pressure treatment reduces the effects of amide group on the chain conformation of nylon 6.
Study on electrical property relaxations of 10 MeV electron beam irradiated HDPE
Authors: Ziaie Farhood , Borhani M. , Majdabadi A. , Kazemi Z. 
Published: August 2014

Abstract Cross linking of the HDPE was performed with high energy electron beam. EPR spectroscopy was used to study the life time of unpaired electron in the irradiated samples. Dielectric constant and dielectric strength almost remained unchanged but, volume resistively and dissipation factor increased and decreased respectively, after irradiation. The results shows that the dissipation factor is going to be recovered slowly with the storing time at room temperature. It is believed that variation of some electrical properties during time after irradiation are due to the effects of free radical and charge trapping remained in the bulk of material.
Dielectric and thermal properties of thermoplastic elastomer gels in the presence of nanographite
Authors: Paglicawan Marissa A. , Kim Jin Kuk 
Published: August 2014

AbstractIn this work, the effect of different nanographite such as expandable graphite (EG) and exfoliated graphite nanoplatelets (xGnP) on the electrical and thermal properties of nanocomposite thermoplastic elastomer gels prepared from a poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) imbibed with an EBcompatible paraffin oil was investigated. The electrical properties have been studied as a function of variation of nanoparticles in the frequency range of 52 to 107 Hz. For all the nanoparticles studied, the dielectric constant increases as the volume content of the nanoparticles in the TPE gels increases. The increase in dielectric constant was fairly smooth with no clear dielectric singularity in the concentration range studied. However, the percolation threshold in the dielectric spectra was clearly seen. The incorporation of a small quantity of nanographite improved the thermal stability of the swollen midblock of TPEGS, since the particles dispersed in this region, thereby increasing the distinct region of oil degradation temperature but no improvement on SEBS matrix. The results showed that size, shape and agglomeration of the particles with high amount of oil in SEBS system played a role in the dielectric properties and thermal stability.
Synthesis and characterization of functional six-membered ring carbonates for the preparation of orthogonal couplers
Authors: Anders Thorsten , Keul Helmut , Möller Martin 
Published: August 2014

Abstract On the basis of commercially available trimethylolpropane (TMP) three six-membered ring carbonates were prepared, substituted with reactive side groups: a chloroformate (2a), an imidazolyl carbamate (2b) and a phenyl carbonate (2c). Their synthesis and characterizations are described and compared to known ring carbonates with reactive side groups. Starting from 2a-c orthogonal couplers 3a and 3b were synthesized for conversion under mild reaction conditions. In a model reaction 2-azidoethyl 2-N-acetylamino-2-deoxy- -D-glucopyranose and tertbutyl- N-(3-aminopropyl) carbamate were linked with coupler 3a via a 1,3-dipolar cycloaddition and a nucleophilic ring-opening reaction. This coupling principle can be used for the preparation of multifunctional polymers or surface coatings at ambient conditions.
The role of clay-montmorillonite on thermal characteristics and morphology of electrospun PAN nanofibrous mats
Authors: Zahed Shami , Naser Sharifi-Sanjani 
Published: August 2014

AbstractPolymer organic-inorganic hybrid nanofibers constitute a new class of materials in which the polymeric nanofibers are reinforced by uniformly dispersed inorganic particles having at least one dimension in nanometer-scale. In the present study, nanofibrous mats of neat and nanocomposite polyacrylonitrile (PAN) were fabricated by electrospinning process. Electrospun PAN and PAN/Na-MMT fibrous mats with the respective mean fiber diameter of about 220 and 160 nm were prepared. The influence of the clay-montmorillonite on the morphology and diameter of nanofibers was investigated by means of scanning electron microscope (SEM) and transmission electron microscope (TEM) techniques. The microscope techniques results suggested that the PAN/Na-MMT composite nanofibers showed the lower mean fiber diameter than the neat PAN nanofibers. Besides, the difference in nanoclay-content has a slight effect on the distribution of fibers diameter. Thermogravimetric analysis (TGA) results suggested that the introduction of clay-nanomaterials improve the decomposition onset and residual weight percentage of mats at about 31°C and 13 %, respectively. The results of X-ray diffraction (XRD) confirmed that the clay-montmorillonite layers were exfoliated in the polymer matrix. The exfoliation of clay layers was further supported by transition electron microscope (TEM) observations.
Interaction of carbon monoxide with PEDOT-PSS/zeolite composite: effect of Si/Al ratio of ZSM-5 zeolite
Authors: Chanthaanont Pojjawan , Sirivat Anuvat 
Published: August 2014

AbstractComposites with poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonic acid), PEDOT-PSS, as the matrix containing ZSM-5 zeolites of various Si/Al ratios in the range of 23-280 at 20% (v/v) were fabricated to investigate the effect of Si/Al ratios on electrical conductivity sensitivity responses towards carbon monoxide (CO). The electrical conductivity responses of PEDOTPSS/ ZSM-5 composites were altered due to the available adsorption sites for CO molecules. The electrical conductivity sensitivity to CO increases with decreasing Si/Al ratios. The composites produce irreversible responses when replacing CO with nitrogen. The addition of ZSM-5 zeolites to the pristine PEDOT-PSS improves the electrical conductivity sensitivity of the composites by enhancing the interaction between PEDOT-PSS and CO gas. The composite of ZSM-5 zeolites with a Si/Al ratio equal to 23 gives the highest electrical conductivity sensitivity toward CO.