bluuebunny/crossref_metadata_2025_split huggingface dataset:
Functionalization of polypropylene and compatibilization of polypropylene/nylon 6 blends with copolymers containing α-methyl styrene units
Authors: Liang Shu-jun , Yang Wan-tai 
Published: August 2014

AbstractIn our earlier works, a new and viable strategy for bulk polymerization of methyl methacrylate (MMA) and styrene (St) with copolymers of poly(AMS-co- GMA) (PAG) of α-methyl styrene (AMS) and glycidyl methacrylate (GMA) has been reported. Herein, we report on the achievements of the compatibilization of the blend system of polypropylene (PP) and Nylon 6 (Ny6) and the functionalization of PP with PAG. The graft reactions of PAG onto PP in solution and molten state were investigated respectively, and the functionalized production was confirmed by the FT-IR spectra. Through SEM, the in-situ compatibilization of PP/Ny6 blends with PAG was observed. And the block copolymers of PP-b-PAG-b-Ny6 in the blends were characterized by FT-IR, which confirmed the “compatibilizing effect” of PAG in the blend system.
Graft polymers prepared by catalytic chain transfer polymerization (CCTP) and applied as solvent-borne dispersants for carbon black dispersions of high solid
Authors: Wang Yongqiang , Zeng Guangpeng , Sun Tairong , Hong Xinlin , Ling Jianxiong , Zhang Gaoyong 
Published: August 2014

AbstractIn this article, a series of graft polymer dispersants were conveniently prepared by the grafting through method, among which the macromonomer was synthesized with one-pot through CCTP technology. Rheology and transmission electron microscopy (TEM) were utilized to study the influence of amide content on the carbon black (CB) dispersing ability of these polymers in xylene. When the tertiary amino groups on the backbone were partly quaternized, the apparent viscosity of the obtained CB suspensions decreased remarkably and the flocculation of the CB particles are effectively suppressed. TEM observations showed that the CB particles were well dispersed by the quaternized dispersant. It could be concluded that the graft polymers with a certain amount of quaternized amino groups (20 wt.%) are an efficient dispersants of CB in organic solvent.
Synthesis, characterization and antifungal properties of N,O-(acyl)-N-(trimethyl) chitosan chloride
Authors: Li Rongchun , Guo Zhanyong 
Published: August 2014

AbstractThree novel water soluble chitosan derivatives: N,O-(acetyl)-N- (trimethyl) chitosan chloride (ATMCS), N,O-(benzoyl)-N-(trimethyl) chitosan chloride (BTMCS), N,O-(chloracetyl)-N-(trimethyl) chitosan chloride (CATMCS) were successfully synthesized. All the derivatives were soluble in water at pH 7. The antifungal properties of the derivatives against two plant fungus Gloeosporium theae-sinensis (G. theae-sinensis) and Phomopsis asparagi (P. asparagi) were studied. The results indicated that the antifungal activities of ATMCS, BTMCS and CATMCS enhanced compared with that of N-(trimethyl) chitosan chloride (TMCS). Against G. theae-sinensis and P. asparagi, BTMCS and CATMCS exhibited much better activities than ATMCS which was may be due to the phenyl and chlorine respectively. Generally speaking, acyl modification of TMCS was effective.
Thermal stability and mechanical properties of modified starch/NR composite
Authors: Wang Zhi-Fen , Li Si-Dong , Fu Xin , Lin Hua , She Xiao-Dong , Huang Jie 
Published: August 2014

AbstractThe starch/natural rubber composite was prepared by blending the modified starch by esterification with natural rubber latex. The modified starch particles are homogenously distributed throughout the natural rubber (NR) matrix. In comparison with the host NR, the thermal stability of composite is significantly improved. The thermal degradation temperatures (T) and reaction activation energy (E) of composite are higher than those of the pure NR. The hardness, stress at 500%, tensile strength, permanent deformation and tear strength of composite increase linearly with the increment of dosage of modified starch.
Characterization of hydroxylated hyperbranched polyesters of fourth and fifth generation
Authors: Murillo Edwin A. , Vallejo Pedro P. , López Betty L. 
Published: August 2014

AbstractHydroxylated hyperbranched polyester (HBPs) of fourth and fifth generation were obtained by three methods; one step (HBP4, HBP5), step by step (HBP4P, HBP5P) and combinations of one step and step by step (HBP1-4, HBP1- 5). The HBPs were synthesized in bulk from 2,2-bis(hydroxymethyl)propionic acid (DMPA) and pentaerythritol (PE) using acid catalysis (p-toluenesulfonic acid) and characterized by infrared analysis, 1H and 13C nuclear magnetic resonance, gel permeation chromatography, vapor pressure osmometry, electro spray ionizationmass spectrometry, dynamic light scattering, refractive index, thermogravimetric and differential scanning calorimetric analysis. The refractive index of HBPs were low, the infrared and nuclear magnetic resonance analysis showed evidence of the occurrence of reaction between from 2,2-bis(hydroxymethyl) propionic acid (DMPA) and pentaerythritol (PE). The molar mass values of the HBPs determined by gel permeation chromatography were different to vapor pressure osmometry measurements due to small hydrodynamic volume of the HBPs. The mass spectrometry analysis showed different acyclic and cyclic units in the HBPs. The distributions of HBPs studied by dynamic light scattering were monomodal in number and volume and bimodal in intensity. The thermal stability of the fifth generation HBPs was higher than that the fourth generation. All HBPs presented amorphous behavior
Isothermal crystallization of high density polyethylene with monomodal and bimodal molar mass distribution
Authors: Tang Yujing , Jiang Zhiyong , Rieger Jens , Enderle Hans-Friedrich , Lilge Dieter , Men Yongfeng 
Published: August 2014

AbstractThe isothermal crystallization behavior of two different high density polyethylene grades with monomodal and bimodal molar mass distribution was investigated by means of differential scanning calorimetry. The results indicate that extensive cocrystallization between linear short chains and long chains with short branches in bimodal polyethylene grade occurred. In contrast, polymer chains of different lengths in monomodal polyethylene exhibit different tendency to crystallize. This finding was explained qualitatively based on a general discussion of the effect of molar mass and branch content/length on crystallization tendency of polymeric chains.
Dependence of comonomer effect and hydrogen effect on internal donor in ethylene/1-hexene copolymerizations with MgCl2-supported catalysts
Authors: Zhang Letian , Fan Lina , Fan Zhiqiang , Fu Zhisheng 
Published: August 2014

AbstractEthylene homopolymerization and copolymerizations with 1-hexene by three types of MgCl2-supported catalysts were compared. Cat-1 contains no internal electron donor (ID), Cat-2 contains phthalic anhydride (PA) as ID, and Cat- 3 contains anisole as ID. The influences of two kinds of ID on comonomer effect, the role of hydrogen, polymerization kinetics in ethylene/1-hexene copolymerization were investigated. The addition of ID improves the catalysts activities in ethylene polymerization. In comparison with ethylene homopolymerization, these ethylene/1-hexene copolymerization systems all showed strong comonomer effects. However, internal donor, especially anisole, weakens the extent of comonomer activity enhancement. When the concentration of 1-hexene is 0.6 mol/L, catalysts activities increase remarkably with adding a small amount of hydrogen. But, the addition of ID reduces the sensitivity of catalyst activity to hydrogen. The introduction of anisole increases the homo-polymerization rate rapidly at the initial stage, but makes it decay earlier. In ethylene/1-hexene copolymerization with hydrogen, the addition of phthalic anhydride as ID can stabilize the polymerization rate, but anisole accelerates the decaying trends. The results are discussed based on a kinetic mechanistic model of the ID effect on ethylene copolymerization.
Epoxy-based nanocomposites with amine modified single walled carbon nanotubes
Authors: Petrea Celina-Maria , Andronescu Corina , Pandele Andreea Madalina , Garea Sorina Alexandra , Iovu Horia 
Published: August 2014

AbstractCarboxylated Single Walled Carbon Nanotubes (SWNT-COOH) were functionalized using different types of amines as modifier agents to improve the compatibility with the epoxy matrix. Covalent attachment was proved by XPS and Raman spectroscopy. TGA showed that only long chain modifier agents improved the thermal stability of modified SWNTs. Epoxy-based composites were synthesized using diglycidyl ether of bisphenol A (DGEBA) as polymer matrix and modified SWNTs as reinforcing agent.
External potential dynamics simulation of the compatibility of T-shaped graft copolymer compatibilizing two immiscible homopolymers
Authors: Li Wei , Jiang Wei 
Published: August 2014

AbstractThe compatibilizing effect of T-shaped graft copolymers between two incompatible homopolymers A and B was studied by using the external potential dynamics (EPD) method based on dynamic self-consistent field theory. We specifically focus on the role of the concentration and the junction position of the graft copolymer on the compatibility. The blend containing compatibilizers exhibits slow dynamics during the phase separation. We observed that the compatiblizers are particularly efficient when the graft point is close to the free end of the backbone chain.
Preparation of a new polypropylene/clay nanocomposites via in situ polymerization
Authors: Naderi Ghasem , Nekoomanesh Mehdi , Mehtarani Reza. , Eslami Hasan. 
Published: August 2014

AbstractNovel polypropylene/clay nanocomposites were prepared by in situ polymerization method with TiCl4/MgCl2/organoclay/internal donor- AlEt3 catalyst. The organo clay used is commercial Closite 15A that is an ammonium saltmodified montmorillonite (AMMT). For preparation of the catalyst, MgCl2 was deposited into the swollen AMMT layers and then TiCl4 and internal donor were loaded on the layer surfaces of AMMT. X-ray diffraction (XRD), transmission electron microscopy (TEM) and rheological measurements were used for characterization of the nanocomposites. The Linear and nonlinear melt-state viscoelastic properties of the polymer matrix and its nanocomposite are also investigated. In the presence of the clay lamellae, a pronounced increase in the low frequency moduli is observed. Transient rheological data reveal a stress overshoot for nanocomposite where there is no significant overshoot for polymer matrix. This stress overshoot can be attributed to the deformation and orientation of the special structure of clay platelets in polymer melts. Finally, experimental data are compared with the predictions of a mesoscopic rheological model.
Terpolymers of N-vinylpyrrolidinone and 1-vinylimidazole as new supports for palladium nanocluster catalysts
Authors: Strzelec Krzysztof , Wąsikowska Karolina , Cypryk Marek , Pospiech Piotr 
Published: August 2014

AbstractTwo terpolymers of styrene, divinylbenzene, and 1-vinylimidazole (S/DVB/VI) or N-vinylpyrrolidinone (S/DVB/NVP) were prepared by radical polymerization. Palladium nanoparticle catalyst has been “heterogenized” by anchoring to these polymers the [PdCl2(PhCN)2] complex via ligand exchange reaction. The formation of coordination bond between S/DVB/VI, S/DVB/NVP terpolymers and Pd2+ ions was studied using infrared and XPS. Immobilized palladium complex was reduced during hydrogenation reaction or by reaction with sodium borohydride. Characterization of polymer supports and palladium catalysts has involved the measurements of the structural parameters in the dry state by the nitrogen BET adsorption, X-ray photoelectron spectroscopy (XPS), AAS spectroscopy and time-of-flight secondary ion mass spectrometry (TOF-SIMS). Both the catalytic systems were found efficient in the hydrogenation of cinnamaldehyde. The stability and a good recycling efficiency of these catalysts make them useful for prolonged use. The factors influencing selectivity of supported catalysts were discussed. The results offer the possibility of using these terpolymers for the immobilization of metal complex catalysts for hydrogenation and other catalytic reactions.
The anomalous behavior of physical-chemical parameters during polymerization of organic-inorganic polymer systems based on reactive oligomers
Authors: Iurzhenko Maksym , Mamunya Yevgen , Seytre Gerard , Boiteux Gisele , Lebedev Eugene 
Published: August 2014

AbstractDependencies of physical-chemical characteristics on structure development during polymerization of organic-inorganic systems (OISs) have been investigated. The non-monotonic behavior of the physical parameters has been found. This effect was explained by complicated structure of OISs, which consists of two interpenetrating hybrid organic-inorganic networks, which are characterized by different rate of the structure formation.
Improving hydrophilicity and protein resistance of silicone hydrogel by plasma induced graft polymerization of 2- methacryloyloxyethyl phosphorylcholine
Authors: Sun Fuqian , Li Xinsong , Xu Jinku , Cao Peiting , Xiao Lijian 
Published: August 2014

AbstractSurface properties of silicone hydrogels used as soft contact lenses play an important role in biocompatibility, conformability and deposition of protein. In this report, the surface hydrophilicity and protein deposition resistance of silicone hydrogel were modified using an atmospheric pressure glow discharge plasma (APGDP) induced graft polymerization of 2-methacryloyloxyethyl phosphoryl choline (MPC). Silicone hydrogel was treated with plasma and exposed to air to form oxide and hydroperoxides at the surface, which initiated surface graft polymerization of MPC. Elemental composition and structure at the surface of silicone hydrogel were characterized through ATR-FTIR and XPS. The data of ATR-FTIR and XPS analyses revealed that MPC was grafted onto the surface of silicone hydrogel. Contact angle measurement was used to evaluate the hydrophilic property of the silicone hydrogel. The MPC grafted silicone hydrogel has the contact angle about 55° when MPC solution with the concentration 10 wt% is applied for graft polymerization. The result showed that graft polymerzation of MPC improved the hydrophilicity of silicone hydrogel efficiently. Bovine serum albumin (BSA) was used as a model to investigate protein deposition resistance of the modified silicone hydrogel. The data obtained by bicinchoninic acid assay revealed that the grafted silicone hydrogels had a significant enhancement of protein resistance.
Molecular dynamics study on the reason of fluorescence quenching of a pyrene-functionalized fluorescent film
Authors: Kong Hongyan , Liu Jing , Wang Liqiang 
Published: August 2014

AbstractExperimentally, the fluorescent intensity of the pyrene-functionalized fluorescent film is reduced by introducing nitrobenzene. In order to fulfill the functional reason of this quenching effect, a molecular dynamics simulation is adopted in this paper. The simulation finds that the structural modification of the pyrene molecules in the film is the main reason for the quenching effects. Result reveals that, in the vacuum environment, the distance between a pair of pyrene ring centers distributes from about 4 Å to 10 Å, and a large number of distances populate at 5.3 Å, which is a suitable distance for excimer emission. The introduction of nitrobenzene results in a decrease of the population of pyrene molecules within that distance, indicating a decrease of excimer emission of the film. In addition, the pyrene molecule rings in the film prone to adopt quasi-coplanar structure in the vacuum, but less likely arrange into a coplanar structure when nitrobenzene is introduced. Study clearly indicates that the structural changes are all caused by the insertion of the incoming nitrobenzene molecules into the previously coplanar pyrene rings. Finally, length and orientation of chain are also analyzed. All the expectations from the simulation studies are basically consistent with the experimental observations.
Preparation and properties of waterborne siloxane-containing polyurethane for moisture permeable textile coating
Authors: Lei Haibo , Luo Yunjun , Ge Zhen , Li Xiaomeng , Wang Shengpeng 
Published: August 2014

AbstractWaterborne siloxane-containing polyurethanes (WSPU) were prepared by polyaddition reaction using poly(tetramethylene oxide)glycol (PTMG), polyethylene glycol (PEG), and α,ω-aminopropyl polydimethylsiloxane (APDMS) as mixing soft segments; 2,2-di(hydroxymethyl)propionic acid, as a hydrophilic chain extender; 1,4-butanediol and isophorone diisocyanate as hard segment; triethylamine as a neutralization agent. The thermal properties of WSPU films were analyzed by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and thermal gravimetric analysis (TGA). The mechanical properties of WSPU film were also investigated. Water vapor permeability (WVP) was examined according to GB_T 12704-1991. The DSC and DMA results indicated that there is a micro-phase separation in the WSPU film. The incorporation of APDMS into PU made the thermal stability of hard segment worse while that of soft segment better. The elasticity of WSPU was improved when the APDMS content was not more than 10%, the vapor permeability of coated fabric increased firstly and then decreased as the APDMS content increased, which was resulted from the hydrophilicity change and microstructure change of membrane. When 10% APDMS was incorporated into the WSPU, the WVP of coated fabric was 2130.15 g/(m2·24h), equal to one coated with a widely used solvent-based PU sample (UECCOAT), and the water resistance (WR) reached 30.0 KPa.
Preparation of PAA/PEO blend nanofibers via electrospinning process
Authors: Shami Zahed , Sharifi-Sanjani Naser 
Published: August 2014

AbstractThe novel poly(acrylic acid)/poly(ethylene oxide) (PAA/PEO) blend nanofibers at 100/0, 80/20, 50/50, 20/80 and 0/100 weight ratios were obtained via electrospinning process. Intermolecular interactions and compatibility of blend fibers were studied by Fourier transform infrared (FT-IR) and differential scanning calorimetry (DSC). It was found that the free-hydroxyl groups, the bonded hydrogen hydroxyl groups and the carbonyl groups absorption bands in the electrospun PAA/PEO fibers shifted with the increase in PEO percentage in the blend. DSC measurements showed the melting point, the glass transition temperature, the melting enthalpy and the crystallinity percentage of pure polymer nanofibers were different compared with blend nanofibers. The results suggested that intermolecular interactions occurred in the electrospun PAA/PEO nanofibers. These interactions made PAA/PEO blends miscible at above-mentioned weight ratios. Additionally, the morphology and the average fiber diameter were investigated using scanning electron microscope (SEM) analysis, which indicated beadless fibers with diameter range of 110 to 280 nm. It was observed that the uniform fibers with the smaller average diameter were obtained in PAA/PEO blends containing PAA dominant content. Finally, the SEM results suggested that the formation of pure PAA nanofibers with concentration of 5 Wt. % would not occur. Whereas, in the same concentration, pure PEO and PAA/PEO blend nanofibers with no bead defects were obtained.
Effect of layered silicates on rheological and mechanical properties and thermal stability of high-molar mass polydimethylsiloxane matrix
Authors: Rabova Veronika , Hron Petr 
Published: August 2014

AbstractThe effect of surface modified fillers based on montmorillonite on rheological and mechanical properties and thermal stability of high-molar mass polydimethylsiloxane matrix was evaluated. Silicone rubber/clay composites were prepared via homogenisation on open two roll-mill followed by torque measurement at two different temperatures. At 30 °C and 100 °C the torque did not extremely differ excepting the mixtures containing Cloisite 15A where it achieved the maximum at 3 phr montmorillonite content, but the tensile strength reached the similar values in all mixtures. Thermogravimetric analysis was utilized to find out the differences in weight decay of composites in silicone rubber/montmorillonite mixtures and in unfilled silicone rubber. Synergism of fillers was also studied and led to tensile strength increase.
Precipitated calcium carbonate as carrier particles of ‘dry liquids’ for post-processing crosslinking reactions
Authors: Vogel Roland , Vučak Marijan , Nover Christoph , Peitzsch Lutz 
Published: August 2014

Abstract Precipitated calcium carbonates (PCC) of different particle morphologies were used as appropriate carrier particles for post-processing crosslinking reactions. Optimum particle morphology and size were estimated for preparation of dry liquids (DLs). The DLs were tested in three different typically crosslinking reactions of polymers.
Reentrant swelling behavior of poly(4-vinyl phenol) gel in aqueous organic solvent mixtures
Authors: Sakurai Michiko , Satoh Mitsuru 
Published: August 2014

AbstractSwelling behaviours of poly(4-vinyl phenol) (P4VPh) hydrogel in various kinds of mixed solvents (methanol, ethanol, 2-propyl alcohol, t-butyl alcohol, acetone, acetonitrile, dioxane, THF and DMSO) have been investigated. With increasing the organic solvent content, the gel first significantly deswelled and then reswelled via lowest swelling points (10-60 vol.% depending the solvent species), and finally showed a second deswelling in the highest content region (typically ≧ 80 vol.%). The rather unique swelling-deswelling sequence was not reproduced when the solvent content was decreased; namely, the backward swelling curves obtained with increasing water composition in the mixed solvents first followed the forward one until the lowest swelling points, then, however, continued the deswelling trend without recovering the initial swelling state in water. This remarkable hysteresis as well as the reentrant swelling with the extra second deswelling has been interpreted in terms of the intermolecular interactions, i.e., hydrogen bonding between the phenol OH groups and the π- π stacking of the phenol rings, by referring to the corresponding results of poly(vinyl alcohol) (PVA) gel system.
Mechanical characterization of rigid π-conjugated polymer on a nanometer scale through nanoindentation
Authors: Liang Bo , Zhang Zhen-lin , Wu Lai-Lei , Zhao Li-cheng , Zhang Shuai , Wang Peng , Zhang Hai-Quan 
Published: August 2014

AbstractThe evaluating mechanical performance of Π-conjugated Polymer films has important significance for application in the micro electronic devices. In this work, authors studied micro mechanical performance of Π-conjugated polymer, poly[2-methoxy-5-(2’-ethyl hexyloxy)-phenylene vinylene] used nanoindentation technique at room temperature and discussed effect of experimental parameter on the effective elastic modulus and hardness of MEH-PPV film. The experimental result indicates the estimating effective elastic modulus and hardness using O & P formula are correlative with load, holding time, and loading rate. Detail analysis in combination with related literature indicated the effective elastic modulus and hardness of MEH-PPV film are approximately 6.79±0.12GP, 0.37±0.16 GP, respectively. Furthermore, increasing the loading rate could decrease the effective elastic modulus and hardness, which was opposite comparing with typical polymer materials (poly (methyl methacrylate) (PMMA) etc ).