bluuebunny/crossref_metadata_2025_split huggingface dataset:
Alginate-based superabsorbent hydrogels composed of carboxylic acid-amine interaction: preparation and characterization
Authors: Yoshimura Toshio , Matsunaga Miyuki , Fujioka Rumiko 
Published: August 2014

AbstractPreparation of superabsorbent hydrogels based on sodium alginate was investigated by mixing aqueous sodium alginate solution and aqueous multivalent amine (ethylenediamine, L-lysine, chitosan) solution, followed by HCl addition. After precipitation in methanol, vacuum drying, and pulverization with mixer, granule products with acid-base interaction were obtained. The preparation condition was investigated by changing the feed amount of amine compound. Among those examined, the highest water absorbency was obtained with the sample for chitosan feed ratio to sodium alginate of 100 mol%, reaching 410 g/g in pure water, 100 g/g in 0.9 % solution, and 80 g/g in 3.5 % NaCl solution. Hydrogels in the present study exhibited good biodegradability irrespective of amine compound.
Synthesis and characterization of novel cyanofunctionalized poly(aryl ether ketone)s
Authors: Zhang Yunhe , Ren Dianfu , Guan Shaowei , Na Ying , Wang Guibin , Jiang Zhenhua 
Published: August 2014

AbstractA series of cyanophenyl-substituted poly(aryl ether ketone)s (PAEKs) have been successfully synthesized from two new bisphenol monomers, (3,4- dicyano) phenylhydroquinone and (4-cyano) phenylhydroquinone respectively, and the thermal behaviour and the solubility have been characterized. These polymers exhibited high glass transition temperatures and excellent thermal stability. The glass transition temperatures ranged from 173 to 217 oC, and 5% weight-loss temperatures were above 470 oC. The solubilities of these polymers have been remarkably improved in common organic solvents over PEEK and PEN. Some polymers formed transparent, strong, and flexible films, with tensile strength of 106.5-125.2 MPa, Young’s moduli of 2.68-3.20 GPa, and elongations at break of 9- 16 %.
Effects of kaolin and maleic anhydride contents on melt elasticity and flexural behaviour of polypropylene/kaolin and unplasticised poly(vinyl chloride)/kaolin composites
Authors: Ariffin A. , Ariff Z.M. , Jikan S.S. 
Published: August 2014

AbstractPolypropylene/kaolin and unplasticised poly(vinyl chloride)/kaolin composites were prepared by directly melt mixing polypropylene (PP) and unplasticised poly(vinyl chloride) (UPVC) with maleic anhydride (MAH) and low cost kaolin via in situ extrusion process. The influences of kaolin particles and MAH in PP and UPVC matrix were discussed through investigating the flexural and morphological properties of filled PP and UPVC composites. The extrudates obtained from the extrusion process were carefully collected in order to investigate the elastic properties (extrudate swell and melt fracture). Results revealed that the above mentioned properties are strongly dependent on the presences of kaolin and MAH in both composite systems. Observation on scanning electron microscopy (SEM) analysis showed that the kaolin books (stacks of kaolin particles) were successfully delaminated thus lead to a well dispersed of kaolin particles in PP and UPVC matrix.
Effects of carbon nanofibers on the crystallization behavior of polyethylene oxide
Authors: Adhikari R. , Lozano K. 
Published: August 2014

AbstractDifferential scanning calorimetry (DSC) was used to investigate the crystallization behavior of polyethylene oxide (PEO) and carbon nanofiber (CNF) filled PEO systems under non-isothermal experimental conditions. The dispersion and distribution of CNF of the composites were studied using scanning electron microscopy. Studies showed the uniform segregation of CNFs in PEO. Different crystallization kinetic models (the modified Avrami equation and the combined approach of Avrami and Ozawa) were used to study the dependence of crystal nucleation on the filler content. Analysis showed that inclusion of CNF to PEO retards the crystallization of PEO at all CNF loading under study
Non-isothermal crystallization kinetics of isotactic polypropylene nucleated with nucleating agent bicyclic [2,2,1] heptane di-carboxylate
Authors: Zhang Yue-fei , Li Xun , Wei Xian-shan 
Published: August 2014

AbstractBicyclic [2,2,1] heptane di-carboxylate (commercial product name: HPN- 68) is a novel nucleating agent with high nucleation efficiency for isotactic polypropylene (iPP). In this paper, the non-isothermal crystallization kinetics of virgin iPP and iPP nucleated with HPN-68 were investigated by means of a differential scanning calorimeter (DSC).The Caze method was used to analyze the non-isothermal crystallization kinetics. The results show that addition of HPN-68 can increase the crystallization peak temperature (Tp) of iPP greatly under the same cooling rate. Under non-isothermal conditions, the addition of HPN-68 changes the spherulite growth pattern of iPP. For virgin iPP, the growth pattern is mainly spontaneous nucleation followed by three-dimensional spherulite growth, while for iPP nucleated with HPN-68, the growth pattern is mainly heterogeneous nucleation followed by three-dimensional spherulite growth.
Preparation and swelling behavior of pH-sensitive and saltresistant amphoteric semi-IPNs hydrogels based on starch phosphate and poly[2-[(methacryloyloxy) ethyl] trimethylammonium] chloride
Authors: Chen Xiaozhen , Xu Shimei , Feng Shun , Wang Jide , Li Xin 
Published: August 2014

AbstractA novel amphoteric hydrogel with semi-interpenetrating polymer networks (semi-IPNs), was prepared by entrapping linear poly[2-[(methacryloyloxy) ethyl]trimethylammonium] chloride (PDMC) into lightly crosslinked starch phosphate- graft-acrylic acid (St-OPO3-g-AA) network in aqueous solution. The influences including the degree of substitution (DS) of starch phosphate, the doses of crosslinker, AA and PDMC were investigated with respect to the swelling capacity. The swelling capacity of hydrogel reached 2016 g/g in deionized water and 121 g/g in 0.9 wt% NaCl solutions, respectively. The swelling behaviors of hydrogel in various salt solutions and different pH buffer solutions were discussed. The amphoteric semi-IPN hydrogels exhibited pH-sensitivity and salt-resistance.
Physicochemical properties and molecular weight characterisation of porcine dermal collagen digested under varying conditions with clostridium histolytic collagenase
Authors: Yeh Jen-taut , Chang Haw-jer , Xiao Li-fang , Yang Li , Zhu Ping , Huang Guo-xian , Yao Wei-Hua 
Published: August 2014

AbstractPorcine dermal collagen is successfully digested by clostridium histolyticun collagenases (CHC) at varying compositions and conditions. Collagen fragments thus prepared, with significantly low molecular weight but visible denaturation temperatures and/or triple helix structures, may be useful for clinical applications. As evidenced by Sodium dodecyl sulfate - polyacrylamide gel electrophoresis (SDS-PAGE) and gel permeation chromatography (GPC) analyses, relatively high molecular weights of α1, α2 subunit, β1 ,β2 dimmers and γ trimmers of the collagen fragments gradually disappear as their incubation temperature and/or time values increase. The time values corresponding to the disappearance of sigmoid plots in the denaturation curves, denaturation endotherm in DSC thermograms and γ bands in SDS-PAGE patterns of digested collagen specimens are the same and reduce significantly as their incubation temperatures increase. Fourier transform infra-red analyses results suggest that the percentages of preserved triple helix structures present in collagen molecules of digested collagen specimens also reduce significantly with increasing the incubation temperature and time values. Possible reasons accounting for the degradation, denaturation and physicochemical properties of digested porcine dermal collagens are explored in this study.
Study on the effect of processing conditions on the mechanical properties of PP/PC/SEBS ternary blends using Taguchi experimental analysis
Authors: Moini Jazani O. , Arefazar A. , Beheshty M.H. 
Published: August 2014

AbstractIn this study, nine ternary polymer blends based on polypropylene (PP)/polycarbonate (PC)/styrene-ethylene-butylene-styrene triblock copolymer (SEBS) with the same compositions (70%wt PP, 15%wt PC, 7.5%wt SEBS and 7.5%wt maleic-anhydride grafted SEBS (SEBS-g-MAH) as a compatibilizer) are prepared using twin screw extruder at different levels of die temperature (235-245- 255 °C), screw speed (70-100-130rpm) and blending sequence (M1-M2-M3) . In M1 procedure, all of the components are dry blended and extruded simultaneously using Brabender twin-screw extruder. In M2 procedure, PC, SEBS, and SEBS-g- MAH minor phases are first pre-blended in twin screw extruder and after granulating are added to PP continuous phase in twin screw extruder. Consequently, in M3 procedure, PP and SEBS-g-MAH are first pre-blended and then are extruded with other components. The influence of these parameters as processing conditions on mechanical properties of PP/PC/SEBS ternary blends is investigated using L9 Taghuchi experimental design. The responding variables are impact strength and tensile properties (young modulus and yield stress) which are influenced by the morphology of ternary blend and the results are used to perform the analysis of variance (ANOVA). It is shown that the resulted morphology, tensile and impact strength are influenced by extrusion variables. Additionally the optimum processing conditions of ternary PP/PC/SEBS blends from Taguchi analysis was achieved.
The properties of sericin/poly(vinyl alcohol) films modified by boric acid
Authors: Wang Qun , Qi Lu 
Published: August 2014

AbstractA group of films mainly composed of sericin and poly(vinyl alcohol) (PVA), using boric acid (BA) as a modifier, were prepared by a technique of solution casting. In this work, the effect of BA and sericin on the mechanical properties and water resistance of the films was analyzed, the interior morphology of the films were described by a scanning electron microscopy (SEM), the thermal stability of the films was characterized by differential scanning calorimetry (DSC), and the reaction mechanism was proposed according to the previous literature and the test of Fourier transform infrared spectrum (FTIR). Results indicated that, the properties of the membrane were the functions of the blend ratio of sercin to PVA and the content of BA. The use of BA increased the tensile strength, improved the water resistance and the thermal stability, and varied the interior morphology of the films. The content of sericin greatly influenced the combination of properties of the films, especially the mechanical properties, interior morphology, thermal stability, and water resistance reducing with the increasing of sericin content. The films have potential to be used in materials, such as skin-care coatings for beauty, percutaneous drug delivery systems for exterior intact skin, due to the characteristics of the components and the good mechanical properties of the films.
Synthesis and thermal stability of star polymer with eight arms using polyhedral oligomeric silsesquioxane as a core
Authors: Liu Lei , Wang Wenping , Guo Xianran 
Published: August 2014

AbstractA Polyhedral oligomeric silsesquioxane (POSS) containing eight 3- chloropropyl groups was synthesized and incorporated into poly(methyl methacrylates) to form star polymer. First, octa(3-chloropropyl) POSS [(ClCH2CH2CH2)8Si8O12] was prepared by hydrolysis and condensation of 3- chloropropyltriethoxysilane, and then two star-shaped POSS/PMMA composites with different POSS content was synthesized at 110 °C, using octa(3-chloropropyl) POSS as an multifunctional initiator, CuCl and 2-2’ bipyridine (Bpy) as catalyst system. The structures of octa(3-chloropropyl) POSS and star-shaped POSS/PMMA composite were characterized by analytical methods including FTIR, NMR, GPC and XRD, with results showing that POSS molecule was successfully formed which accorded well with the reported work and was dispersed into PMMA matrix evenly by atom transfer radical polymerization method. The TGA results indicated that synthetic POSS molecule possessed good thermal stability, and the thermal stability of POSS/PMMA composite enhanced with the increase of POSS content, which is due to the incorporation of inorganic POSS molecule
Preparation of submicron ion-exchange fibers and application in copper ions removal from aqueous solutions
Authors: Feng Shuqin , Shen Xinyuan 
Published: August 2014

AbstractThe submicron ion-exchange fibers (IEF) of polystyrene (PS) and styrene-isoprene-styrene block copolymer (SIS) blends (80/20, w/w) obtained by electrospinning technology were further sulfonated with sulfuric acid to produce strong acidic cation ion exchange fibers. Scanning electron microscopy (SEM) images showed that there were obvious increase in the diameters, scratches, cracks, and micro-pores on the rough IEF surface. Fourier transform infrared (FTIR) spectroscopy analysis showed there were many sulfonated acid groups introduced onto the benzene wreath of styrene. The maximum adsorption capacity and the adsorption rate of copper ions were carried out and their removal rate determined by spectrophotometry. The results of the adsorption for copper ions showed that submicron IEF from PS/SIS blends with a high porosity (85%) and a high specific surface (760 m2/g) possess a rapid adsorption rate and a high ion adsorption amount (305.9 mmg/g). This high adsorption capacity suggests that the IEF can be efficiently applied to filter out toxic metal ions, and has excellent efficiency to remove copper ions from aqueous solution.
Preparation and characterization of hydroxybutyl chitosan
Authors: Zhu Bin , Wei Changzheng , Hou Chunlin , Gu Qisheng , Chen Dajun 
Published: August 2014

AbstractThe insolubility in neutral condition is a major problem that confronts the further development of processing and uses of chitosan. Special emphasis has been put on the chemical modification of chitosan to explore its full potential. Studies on these methods are also encouraging and many kinds of water-soluble and alcohol-soluble derivatives have appeared. In this article, hydroxybutyl chitosan, a new type of thermosensitive polymer, was prepared through the chemical modification of 1,2-epoxybutane. Hydroxybutyl chitosan solution underwent sol/gel phase transition at a certain temperature lower than 20 °C, however, at high temperature, hydroxybutyl chitosan can form hydrogel with a certain mechanical strength. Hydroxybutyl chitosan could be an ideal themosensitive material applied in drug delivery system, tissue engineering and other biomedical fields.
Characterization of orientation in polyethylene by scratch testing
Authors: Vigueras-Santiago Enrique , Hernández-López Susana , Camacho- López Marco A. , Brostow Witold 
Published: August 2014

AbstractMicroscratch experiments were performed to evaluate effects of uniaxial stretching by 200 % in low density polyethylene (LDPE) along parallel and perpendicular directions with respect to stretching. Penetration depth, healing depth and viscoelastic recovery have been determined. Clear orientation effects are seen. The direction parallel to the extension axis shows strong resistance to scratching and also the highest recovery (a memory effect). Unoriented material exhibits behavior intermediate between that of oriented samples in parallel and perpendicular directions. The sliding wear was determined by multiple scratching along the same groove and here also was found orientation dependence. Polarized micro-Raman experiments on the oriented LDPE samples were carried out. Since scratching and sliding wear results are strongly affected by polymer orientation, one can use both kinds of tests as a measure of orientation - and also to vary orientation to control tribological properties.
Effect of PVP content on the quaternized polysulfone in blend membranes
Authors: Huang Aibin , Xiao Chaobo 
Published: August 2014

AbstractA series of blend membranes of quaternized polysulfone (QPSF) and polyvinylpyrrolidone (PVP) were obtained by a novel method. The procedure of quaternization of chloromethylated polysulfone and the process of blend are synchronous. These blend membranes, prepared with quaternized polysulfone (QPSF) and polyvinylpyrrolidone (PVP), were characterized by FTIR, X-ray diffraction (XRD), tensile tests and scanning electron microscopy (SEM). The degrees of swelling of the membranes in some solvent were also measured. The ionic resistances of the membranes were measured too. With the increasing of PVP content, the properties of the membranes have changed. The tensile strength of blend membrane dropped while the degrees of swelling of the membranes in water increased. The ionic resistance of the membrane dropped with the PVP content increasing in blend membranes. The polyvinylpyrrolidone (PVP) has good compatibility with quaternized polysulfone in blend membranes.
Research of mechanical strength enhanced fibrin-PLGA hybrid scaffold with its effect on proliferation of rMSC
Authors: Zheng Qing , Zhao Xiaojun 
Published: August 2014

AbstractAs a tissue engineering biomaterial, fibrin possesses outstanding biodegradable and biocompatible features except for its weak mechanical strength which limits its ranges of further application. In this study, hybrid scaffold was obtained by mixed fibrinogen and thrombin solution homogeneously in the presence of various amounts (0, 1, 2, and 4 mg, respectively) of non-woven fabric of PLGA fiber through traditional freeze-dried method to improve the mechanical strength while keeping its biological characters. The observation by scanning electron microscopy (SEM) showed that all the fibrin sponges have porous and interconnected pore structure, irrespective of the amount of PLGA fiber incorporated. In the measurement of the scaffold shrinkage, the percent of shrinkage of fibrin sponge incorporating PLGA fiber decreased when the amount of PLGA fiber incorporated increased compared with the fibrin sponge without PLGA fiber. The compression test suggested that compression modulus of PLGA fiber incorporated fibrin sponge significantly increased against the fibrin sponge without PLGA fiber; the incorporation of PLGA fiber enabled the mechanical strength of fibrin sponge to be effectively enhanced. Rat mesenchymal stem cells (rMSCs), which is of high potential to induce tissue regeneration, was selected to seed and culture in the fibrin scaffolds with or without PLGA fiber, and the number of rMSC was tested by DNA assay and calculated to examine which sponge was more favourable for rMSC to proliferate. The results reveal that the incorporation of PLGA fiber reinforced the fibrin scaffolds and maintained their intraspace. MSCs proliferated in fibrin scaffold with PLGA fiber was obviously on average more than that without PLGA fiber in vitro.
Combustion and thermal behaviors of the novel UV-cured intumescent flame retardant coatings containing phosphorus and nitrogen
Authors: Xing WeiYi , Song Lei , Hu Yuan , Lv Xiaoqi , Wang Xin 
Published: August 2014

AbstractPhosphorus-containing tri(acryloyloxyethyl) phosphate (TAEP) was blended with triglycidyl isocyanurate acrylate (TGICA) in different ratios to obtain a series of UV curable intumescent flame retardant resins. The fire properties of the cured films were characterized by limited oxygen index (LOI), UL 94 and Cone Calorimeter. A distinct synergistic effect was found between TAEP and TGICA. The sample TAEP2 had the highest LOI (44) value among all resins. The cone calorimeter results showed that the sample TAEP2 had the lowest peak heat release rate (297 KW/M2). The thermal degradation was monitored by thermogravimetric analysis (TGA) and real-time Fourier transform infrared spectroscopy (RT-FTIR). The degradation mechanism is suggested in which the phosphate group in TAEP first degraded to form poly(phosphoric acid)s, which further catalyzed the degradation of the material to form char with emission of nitrogen volatiles from TGICA, leading to the formation of expanding char.
Synthesis and characterization of α-butyl-ω-{3-[(2,2- dihydroxymethyl)-propionyloxy]}propyl polydimethyl siloxane
Authors: Zhang Meng , Wu Yuanjuan , Zhang Qingsi , Li Tianduo 
Published: August 2014

AbstractA novel polydimethylsiloxane containing two primary hydroxyl groups at one single chain end was synthesized by five-step reactions which included esterification, hydroxyl protection, anionic ring-opening polymerization, hydrosilylation and deprotection. The prepared compounds in each step were characterized. The results showed that at each step synthesis was successfully carried out and objective products could be achieved.
A convenient method to acquire third-order NLO materials by ATRP
Authors: Wu Jiang , Xu Qingfeng , Xia Xuewei , Li Najun , Lu Jianmei , Ge Jianfeng , Wang Lihua 
Published: August 2014

AbstractA third-order nonlinear optical (NLO)-active initiator (NA3PH) was synthesized to prepare a NLO-active polystyrene (NA3PH-PSt) via atom transfer radical polymerization (ATRP). The polymerization initiated by NA3PH was studied and the third-order NLO properties of the obtained NA3PH-PSt were investigated by Z-scan technique in comparison with NA3PH. Results show that the endfunctionalized polystyrene possesses third-order nonlinear optical susceptibilities (10-11esu) close to NA3PH. In addition, NA3PH-PSt has good thermal stability and solubility, which holds potential for further application in NLO devices.
Synthesis of long chain semiaromatic polyamides based on decanediamine
Authors: Wang Wenzhi , Li Ruixue , Liu Baoyu , Zhang Yonghua 
Published: August 2014

AbstractLong chain semiaromatic polyamides were synthesized by the reactions of decanediamine with various aromatic diacids, and characterized by Fourier transform infrared spectrum (FT-IR) and nuclear magnetic resonance (1H-NMR). The thermal behaviours were determined by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The solubility, dynamic mechanical, physical and mechanical properties of the polyamides were also investigated. The resultant polyamides have intrinsic viscosity ranging from 1.7 dL/g to 2.1 dL/g. Their melting temperatures range from 305 °C to 343 °C, and the glass transition temperatures fall in the range of 125 °C - 130 °C. The tensile strength of the polyamides is above 100 MPa.
Poly(α-hydroxyacids) in biomedical applications: synthesis and properties of lactic acid polymers
Authors: Lipsa Rodica , Tudorachi Nita , Vasile Cornelia 
Published: August 2014

AbstractPoly( -hydroxy acids), especially poly(glycolic acid) (PGA), poly(lactic acid) (PLA) and their copolymers poly(lactic-co-glycolic acid) (PLGA) are novel class of commodity polymers, also used in biomedical applications. They can be synthesized with a controlled biodegradation rate and are biocompatible, bioresorbable and approved by US Food and Drug Administration (US FDA) for clinical use. Lactic acid polymers are developed in medicine (sutures, implants, orthopaedics, tissue engineering), pharmacy (controlled drug delivery systems) as well as in packaging, agriculture (mulch films, seed preservation), food applications, etc. The paper reviews recent literature data concerning lactic acid polymers synthesis (polycondensation, ring opening polymerization), physical (thermophysical, solubility, miscibility), mechanical properties, degradation behaviour, emphasizing on the poly(α -hydroxyacids) and lactic acid polymers applications in medicine and pharmacy.