bluuebunny/crossref_metadata_2025_split huggingface dataset:
Compatibilization of NR/EVA blends by natural rubber grafted poly(dimethyl(methacryloyloxymethyl)phosphonate) compatibilizer
Authors: Intharapat Punyanich. , Derouet Daniel , Gohier Frédéric , Nakason Charoen 
Published: August 2014

AbstractGraft copolymer of natural rubber (NR) and poly(dimethyl (methacryloyloxymethyl) phosphonate (PDMMMP) (i.e., NR-g-PDMMMP) was prepared and used as a blend compatibilizer in 50/50 NR/EVA simple blends. Influence of various loading levels of NR-g-PDMMMP (i.e., 0, 1, 3, 5, 7, 9, 12 and 15 wt% of NR) on rheological, dynamic, mechanical and morphological properties was investigated. The results showed that the best compatibilization effect was observed in the blend with a loading level of NR-g-PDMMMP at 7 wt%. That is, the highest complex viscosity, tensile strength, elongation at break as well as the lowest values of tension set and tan δ value (i.e., damping factor) were observed. This indicates the highest mechanical strength and the supreme elastic response of the material. Morphological properties of 50/50 NR/EVA blends with any loading levels of NR-g-PDMMMP compatibilizer showed co-continuous phase system. However, in the NR/EVA blend with NR-g-PDMMMP at a loading level of 7 wt%, the finest phase morphology was observed. The 50/50 NR/EVA blend with lower and higher loading amounts of NR-g-PDMMMP compatibilizer exhibited inferior dynamic, mechanical properties as well as larger phase morphologies.
Determination of vinyl acetate propagation rate coefficients via high frequency pulsed laser polymerization
Authors: Junkers Thomas , Voll Dominik , Barner-Kowollik Christopher 
Published: August 2014

AbstractNew data on the propagation rate coefficient, kp, of vinyl acetate (VAc) are obtained via the IUPAC recommended method of pulsed laser polymerization - size exclusion chromatography (PLP-SEC) operated at 500 Hz laser repetition rate. An apparent dependency of the experiment’s outcome on the laser pulsing rate is identified with kp being about 25 % larger at 500 Hz compared to 100 Hz. The temperature dependence of kp was determined to fit ln kp = 17.12 - 2621 K/T; data is in generally good agreement with literature values when the previous underestimation of kp by 100 Hz laser pulsing experiments is taken into account.
Konjac glucomannan nanocrystals prepared by acid hydrolysis
Authors: Huang Jin , Gao Shanjun , Shen Xiaomeng 
Published: August 2014

AbstractKonjac Glucomannan (KGM) nanocrystals were prepared from the disruption of KGM by acid hydrolysis. Effect of hydrolysis time on the degree of hydrolysis of KGM and the size of nanocrystals were investigated. Results from Infrared spectroscopy (IR) showed that KGM nanocrystals were still composed of mannose and glucose like the raw KGM. Results from X-ray diffractometer (XRD) revealed that the amorphous state of raw KGM had changed into a typical β-type crystalline state of KGM nanocrystals. Results from transmission electron microscopy (TEM) indicated that irregularly oval shape nanocrystals with the mean size of 15-40 nm were observed.
Comparison of Matrix Assisted Laser Desorption/ Ionization Mass Spectrometry with Electrospray Ionisation Mass Spectrometry for the characterisation of semitelechelic polyethylene oxide
Authors: De Winter Julien , Vachaudez Magali , Coulembier Olivier , Dubois Philippe , Flammang Robert , Gerbaux Pascal 
Published: August 2014

AbstractMALDI-MS methodology is nowadays considered as a very reliable technique to determine the chemical structures and the molecular weight distribution of a synthetic polymer. At variance, ESI-MS occupies only a small segment in the analysis of polymers mainly because of the formation of multiple charged ion distributions, which interfere with the molecular distribution in the mass spectra of synthetic polymers. In the present communication, we want to demonstrate that, when applied to fragile polymer samples, both techniques can lead to misinterpretation since in source decomposition of the ionized oligomers can sometimes not be avoided. An accurate knowledge of the source parameters and their influences is therefore a prerequisite prior to start the analysis of the MS data. Moreover, we would like to propose that the best MS methodology to analyze fragile synthetic polymers is to associate the data obtained by both the MALDI-MS and ESI-MS techniques.
Mechanical and hygrothermal aging study on quaternary polyamide 6/maleated styrene-ethylene-butylenestyrene/ clay/short glass fiber hybrid composites
Authors: Rua Yonghong , Tjong Sie Chin 
Published: August 2014

AbstractElastomer toughened PA6 hybrids reinforced with short glass fiber and organoclay were fabricated by melt mixing and injection molding. The structure, mechanical and hygrothermal aging behaviors of such hybrids were investigated. XRD patterns showed the absence of clay diffraction peaks in low angle region. TEM observation showed that the organoclay platelets are fully exfoliated in the PA6 matrix of hybrids. Mechanical tests demonstrated that the incorporation of organoclay into PA6/SEBS-g-MA/SGF composite lead to a significant enhancement in the elastic modulus of hybrids. However, the clay additions reduced the tensile ductility and fracture toughness of hybrids. The tensile stiffness and strength of the clay reinforced hybrids deteriorated but the tensile ductility enhanced markedly upon exposure to hygrothermal aging.
In situ formation of silver nanoparticles based on dendriticlinear amphiphilic block copolymer micellar templates
Authors: Wang Huiqing , Shao Ziqiang , Wang Wenjun , Wang Feijun 
Published: August 2014

AbstractDendritic-linear amphiphilic block copolymer, G1-b-PEG, was synthesized through a convergent method. The first generation benzylic dendritic polyether, G1-Cl, was synthesized, and benzylic dendritic polyether, G1-Cl, was used to react with linear monohydroxyl terminated MPEG in alkaline solution via a convergent method. The copolymer was characterized by 1H-NMR. The amphiphilic block copolymer could self-assemble into micelles in aqueous solution, which were used as templates to prepare dispersed silver nanoparticles in water. The morphology and structure of the hybrids were characterized by transmission electron microscopy (TEM) and ultraviolet spectroscopy (UV), 1H-NMR. An absorbance peak at 406 nm appeared after reduction in the UV spectrum. The average diameter of G1-B-PEG /Ag hybrid micelles was 186 nm, and the sliver nanoparticles are stable in aqueous solution due to the stabilization of the dendritic-linear micelles.
Synthesis and characterization of temperature/pH-sensitive hydroxypropylcellulose/ sodium alginate hydrogel
Authors: Li Hui , Gong Guo-li 
Published: August 2014

AbstractA series of temperature and pH responsive hydrogels were synthesized by using hydroxypropylcellulose (HPC) as temperature natural sensitive material, sodium alginate (SA) as pH sensitive material. The effect of SA to LCST has been studied and the mechanism of the influence has been presented. In addition, the swelling ratio and controlling factor of swelling process were all researched in this paper. The main results obtained are as follows: the LCST decreased gradually as SA was added into HPC; the HPC/SA hydrogel responded to both temperature and pH value of the medium; the swelling ratio reached maximum value at pH value of 6.
Rheological characterization of polystyrene melts dissolved with supercritical nitrogen fluid during microcellular injection moulding
Authors: Chen Shia-Chung , Chung Ming-Hsiu , Lin Yu-Wan , Hsu Ping-Shun , Hwang Shyh- Shin , Hsu Pe-ming 
Published: August 2014

AbstractThere are several benefits of using the supercritical fluid microcellular injection moulding process. The part weight, melt temperature, viscosity, moulding pressure, shrink/warpage, and cooling/cycle time are all significantly reduced. The purpose of this study is to investigate the rheological behaviour of PS melt dissolved SCF of nitrogen during Microcellular Injection Moulding process applied with Gas Counter Pressure (GCP) technology. The application of gas into the mould cavity prior to the melt filling provides a counter force against the melt front advancement, restricting the foaming process during the melt filling stage. A slit cavity is designed to measure the pressure drop of polystyrene mixed with 0.4wt% supercritical nitrogen fluid under different mould temperatures (185°C, 195°C, and 205°C), injection speeds (5, 10, and 15 mm/s) as well as counter pressures (0, 150, 300 bars). It was found that melt viscosity is reduced by up to 30% when GCP is increased from 50 to 150 bar as compared to conventional injection moulding. The non-nucleation mixture melt obtained by using a GCP of 300 bar has 32~49% lower viscosity. In addition, the glass transition temperature, Tg, was found to be reduced from 96 °C to 50 °C when the applied GCP is 300 bar.
Synthesis and characterization of novel benzoxazines containing nitrile and allyl groups and their polymers
Authors: Zhang Hongchun , Lu Zaijun 
Published: August 2014

AbstractA p-cyanophenol and allylamine based benzoxazine has been synthesized and characterized. This benzoxazine has nitrile and allyl functionalities that can polymerize, resulting in a highly crosslinked material. The DSC spectra of novel benzoxazine monomer reveal that incorporation of the nitrile and allyl group greatly decreases the ring-opening temperature of oxazine rings (140°C). The IR spectra of curing process indicate that the polymerization of oxazine ring accompany with the curing reaction of allyl and nitrile groups. Benzoxazine monomers with one or none of the two functionalities were also prepared to study structure effect on thermal properties of resulted polymer. The comparison of results confirms that introducing the two functionalities improved glass transition temperature (238 °C), thermal stability of polybenzoxazine (T5%=340 °C), and char yield (57%).
MgH2/PEG initiating system for ring opening polymerization of lactone and lactide
Authors: Guerrouani Nadia , Mas André , Schué François 
Published: August 2014

AbstractDihydroxy-terminated poly(ethylene glycol) and MgH2 form an efficient initiating system for the ring opening polymerization of ε-caprolactone and Llactide. Polycaprolactone-block-polyethylene glycol-block-polycaprolactone and polylactide-block-polyethylene glycol-block-polylactide were synthesized in bulk at 120 °C for 16 h under argon. MgH2 provided a faster polymerization rate compared with other initiating systems based on non toxic metals used under vacuum. Molecular weight of copolymers varied according to the monomer / ethylene oxide units ratio. The developed procedure led to easy polymerization with better control of the design, molecular weight and polydispersity of the final material. Copolymers were characterized by SEC, DSC, 1H and 13C NMR and IR. Micelles in aqueous solutions were prepared by finding balance between hydrophobic polyester and hydrophilic polyethylene glycol blocks. Interest for this method is since the use of MgH2, environmental chemical, absence of solvent and vacuum techniques and the possible recovery of solid material without further operation.
Interfacial properties of all-polypropylene composites
Authors: Houshyar Shadi , Shanks Robert A. 
Published: August 2014

AbstractPreparation and characterization of novel composites, consisting of polypropylene (PP) fibres in a random poly(propylene-co-ethylene) (PPE) matrix, were investigated. These composites possess unique properties, due to chemical compatibility of the two polymers allowing creation of strong physico-chemical interactions and strong interfacial bonds. The difference between the melting temperatures of PP fibre and PPE was exploited in order to establish processing conditions for the composites. Suitable conditions were chosen so that the matrix was a liquid, to ensure good wetting and impregnation of the fibres, though the temperature must not be high enough to melt the fibres. The morphology of the composites was investigated using optical and scanning electron microscopy. Optical microscope images showed that transcrystallization of the matrix was observed on PP fibre surfaces. SEM photographs displayed a thin layer of matrix on the reinforcement, attributed to good impregnation and wetting of the fibres. Adhesion between PPE matrix and PP fibres was characterized using a microbond test inspired by a fibre pull-out technique. The results showed that adhesion was appreciably increased when PP fibres were used instead of glass fibres in the matrix. Nevertheless, thermal processing conditions of the composites caused reduction in mechanical behaviour of the reinforcement.
Preparation and Investigation of chitosan nanoparticles including salicylic acid as a model for an oral drug delivery system
Authors: MojtabaTaghizadeh Seyd , Javan Raveled Safaei 
Published: August 2014

AbstractThe aim of this study was to prepare a biocompatible and biodegradable nanoparticulate drug delivery system to increase the efficiency and bioavailability of oral drugs. Chitosan nanoparticles containing salicylic acid (SA) were prepared by emulsion method. The morphology of nanoparticles was characterized by scanning electron microscopy (SEM). Particle size distribution was examined by laser light scattering. The drug released and drug content was examined by UVspectroscopy. The effects of different initial drug loading on the drug content and drug released were investigated. The nanoparticles were spherical and the average size of them was 300 nm, the drug content was in the range of 20-35%. All the nanoparticles had a burst release initially and the burst release behavior of them conformed best to higuchi model. The release of SA from chitosan nanoparticles was Fickian.
Preparation and characterization of poly(propylene carbonate)/polystyrene composite films by melt-extrusion method
Authors: Huihong Liu , Lisha Pan , Qiang Lin , Nai Xu , Lingbin Lu , Sujuan Pang , Songbao Fu 
Published: August 2014

AbstractPoly(propylene carbonate) (PPC) is a new biodegradable aliphatic polycarbonate with poor thermal stability and mechanical properties which shows difficulty in forming film by melt-extrusion technology. Through the addition of polystyrene (PS), the melt-extrusion film processability, thermal stability and mechanical properties of PPC was improved largely. PPC/PS films were prepared in the the melt-extrusion process successfully. DSC data showed that there was some degree of miscibility between PPC and PS. SEM showed good dispersion of PS particles into PPC matrix. Improved mechanical properties and thermal stability of PPC/PS blends were attributed to homogeneous dispersing and stronger interfacial interaction of PS and PPC. These results indicate that blending PPC with PS is an efficient and convenient method to improve the properties of PPC, and the composites can be used as a common packaging material for a wide range of applications.
An algorithm for Monte Carlo modeling of hyperbranched polymerization
Authors: Lechowicz Jaromir B. , Galina Henryk 
Published: August 2014

AbstractA model hyperbranched polymerization involving irreversible reactions between functional groups A and B in a mixture of comonomers ABxand Bn(x = 2, 3,…; n = 1, 2, …) has been studied. An algorithm simulating the reactions in computer memory was developed and converted into computer code. Simulations were applied to optimize the procedure of feeding monomers AB2 and B2.
macroporous hydrogels based on 2-hydroxyethyl methacrylate. Part 7: Methods of preparation and comparison of resulting physical properties
Authors: Přádný Martin , Šlouf Miroslav , Martinová Lenka , Michálek Jiří 
Published: August 2014

AbstractFive methods of preparation of macroporous hydrogels are described and compared: precipitation polymerization, polymerization in presence of salt, polymerization in presence of gas-releasing compound, lyophilization and electrospinning. Crosslinked copolymers based on 2-hydroxyethyl methacrylate were selected as model hydrogels. Hydrogels were characterized by SEM microscopy, porosity, communicating/non-communicating pore ratio, pore sizes and their distributions. The advantages and drawbacks of the methods of preparation, modification of hydrogel properties, reproducibility and issues related to their preparation are discussed. The most convenient method was preparation in presence of salts. One type of porous hydrogel was based on a hydrogel matrix composed of nanofibers prepared by electrospinning method. The nanofibers have shown unique properties due to their large specific surface. The least suitable method seems to be the preparation of porous hydrogels by polymerization using gas (nitrogen) releasing initiator, 2,2´-azobisisobutyronitrile. The use of prepared porous hydrogels is intended especially for scaffolds in tissue engineering.
Probing superficial and mechanical behaviors of nanosilica incorporated poly(acrylate) hybrid latexes
Authors: Chen Li , Wang Lifang , Yan Lili , Gu Yuansong , Chen Su 
Published: August 2014

AbstractWe reported the synthesis of nanosilica/poly(acrylate) (PA) core-shell hybrid latexes via emulsion polymerization with nanosilica as the core and acrylic copolymer as the shell. Firstly, the nanosilica was surface-functionalized with the coupling agent 3-aminopropyltriethoxysilane (APTS). Then the nanosilica tethered APTS (SIAP) further connected to acrylate monomer by covalent bond during emulsion polymerization, leading to the formation of nanocomposite PA latexes. The microstructures of obtained nanosilica/PA hybrids (SIAP/PA) were characterized by attenuated Total Reflection Fourier Transform Infrared (ATRFTIR), FT-IR imaging, transmission electron microscopy (TEM) and atomic force microscopy (AFM) in detail. The FT-IR imaging indicated the perfect compatibility between the core and the shell. Additionally, the properties of hybrid films were investigated by water contact angle analysis and mechanical property measurement. The SIAP/PA composites exhibit hydrophobic behavior, enhanced tensile strength (about 1.5 times) and high elongation (1262%).
Tensile behaviour of rubber-modified polyester resin materials
Authors: Munyati M.O. , Lovell P.A. 
Published: August 2014

AbstractPolymer blends comprising an unsaturated polyester resin and dispersed particles were prepared. Rubbery particles were synthesized by sequential emulsion polymerization and had core-shell morphology. Curing of materials was carried out at ambient temperature and subsequently post cured at elevated temperatures to obtain materials of consistent properties. Materials made of different particle content were prepared and their tensile properties evaluated. Effect of matrix ductility was investigated by inclusion of ethyl acrylate in the polyester resin composition. Deformation mechanisms involved in these materials were examined using transmission electron microscopy (TEM) and real-time small angle X-ray spectroscopy (RT-SAXS). Incorporation of rubbery particles in the polyester resin was found to generally improve the tensile properties of the materials. Furthermore, the deformation mechanisms were found to involve cavitation/debonding processes as evidenced from stress whitening in the failed specimen and from real-time small angle X-ray scattering experiments.
Synthesis of UV-curable resin/ZnO composite films as pH buffering material
Authors: Yin Hui-En , Kuo Kuo-Huai , Chiu Wen-Yen 
Published: August 2014

AbstractUV-curable Resin/ZnO composite film, which has advantages including UV-curable property and pH buffering ability, was prepared through incorporation of pre-made ZnO nanoparticles and UV-curable resin. The resins we used in this paper were R1 and R10. R1 was Bisphenol A epoxy diacrylate (EA) dissolved in propylene glycol monomethyl ether acetate (PGMEA), and R10 was synthesized by EA, pyromellitic dianhydride (PMDA) and 2-hydroxyethyl methacrylate (HEMA), and then followed by characterization using FTIR and GPC. The ZnO nanoparticles were prepared from Zinc acetate and Sodium hydroxide in 1-butanol by hydrothermal method. “Physical Adsorption” and “Mixture Coating” were two ways to prepare the Resin/ZnO composite film. Then, the pH buffering ability of the Resin/ZnO composite film was evaluated by soaking the film in the pH4 or pH10 solution, and the variation of pH value was recorded with time. The result shows that F10/ZnO composite film obtained from R10/ZnO by “Physical Adsorption” method could be a good buffering material to justify either pH4 or pH10 solution to pH7.4 in 5 min and F10/ZnO composite film by “Mixture Coating” method could be a long time pH buffering material.
Effect of marble particle size and gamma irradiation on mechanical properties of polymer concrete
Authors: Martínez-Barrera Gonzalo , Brostow Witold 
Published: August 2014

AbstractEffects of gamma radiation and the marble particle size on compressive properties and the dynamic elastic modulus of polymer concretes (PCs) were studied. The PCs had a composition of 30 % of unsaturated polyester resin and 70 wt. % of marble as aggregate. Different types of PC were developed with the combination of one, two or three marble-particle sizes. The materials were submitted to 5, 10, 50, 100 and 150 kGy of radiation doses. Both the compressive properties and the dynamic elastic modulus values depend on the combination of the marble-particle sizes and the applied radiation dose. Higher numbers of dispersed particles per unit volume provide more resistance to crack propagation. On the other hand, longer particles give more reinforcement. As a result of these two competing effects, medium size marble particles provide the highest compression modulus
Fabrication and characterization of collagen (shell) /thermoplastic polyurethane (core) composite nanofibers by coaxial electrospinning
Authors: Chen Rui , Qiang Li Xiao , Ke Qin Fei , He Chuang Long , Mo Xiu Mei 
Published: August 2014

AbstractCoaxial-electrospinning is a new method used in tissue engineering and drug delivery field. It can spin nanofibers with shell-core structure through electrospinning of two polymer solutions. In this study, collagen was used as the outer layer or the shell and thermoplastic polyurethane (TPU) was used as the inner layers or the core. A series of tests were conducted to characterize the compound nanofiber and its membrane. Morphology and microscopy of the ultrafine fibers were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), whereas the fiber diameter distribution was understood using image visualization software (ImageJ) and measurements of solution viscosity and conductivity. Mechanical measurements were carried out by applying tensile test loads to samples which were prepared from electrospun ultra fine non-woven fiber mats. The results demonstrated that these composite nanofibers had the characters of native extracellular matrix and they could be designed as the scaffold for tissue engineering and functional biomaterials.
Flexible plasticized PLA with high crystallinity obtained by controlling the annealing temperature
Authors: Ran Xiang-Hai , Jia Zhi-Yuan , Yang Yu-Ming , Dong Li-Song 
Published: August 2014

AbstractIn this study, plasticized polylactide (PLA) was prepared by blending PLA with high stereoregularity and poly(ethylene glycol-co-propylene glycol) (PEPG) in a batch wise mixer and pressed into films. The influence of annealing temperature on the thermal properties and tensile properties of quenched plasticized PLA was investigated by DSC, DMA and tensile tests. It was found that plasticized PLA after cold crystallization can keep its high flexibility with an elongation at break over 300% by choosing a proper annealing temperature. The difference of crystallization morphology formed at the different annealing temperature was thought as a possible reason for this result.