bluuebunny/crossref_metadata_2025_split huggingface dataset:
Controlled synthesis of low‐molecular‐weight polyethylene waxes by titanium–biphenolate–ethylaluminum sesquichloride based catalyst systems
Authors: Umare Prashant S. , Rao Karumanchi , Tembe Gopal L. , Dhoble Deepa A. , Trivedi Bhavna 
Published: February 2007

AbstractSoluble complexes of titanium(IV) bearing sterically hindered biphenols, such as biphenol, 1,1′‐methylene di‐2‐naphthol, 2,2′‐methylene bis(4‐chlorophenol), 2,2′‐methylene bis(6‐tert‐butyl‐4‐ethyl phenol), and 2,2′ ethylidene bis(4,6‐di‐tert‐butyl phenol), were prepared and characterized. These catalyst precursors, formulated as [Ti(O∧O)X2], were active in the polymerization of ethylene at high temperatures in combination with ethylaluminum sesquichloride as a cocatalyst. The ultra‐low‐molecular‐weight polyethylenes (PEs) were linear and crystalline and displayed narrow polydispersities. The catalytic polymerization leading to PE waxes in this reaction exhibited unique properties that have potential applications in surface coatings and adhesive formulations. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1531–1539, 2007
Determination of the molecular characteristics of commercial polyethylenes with different architectures and the relation with the melt flow index
Authors: Teresa Rodríguez‐Hernández M. , Angulo‐Sánchez J. L. , Pérez‐Chantaco A. 
Published: February 2007

AbstractThe molecular weight distribution curves of several commercial polyethylene samples were evaluated by high‐temperature gel permeation chromatography with two detectors (a refractive‐index detector and a viscometer) to determine the molecular sizes and architectures (branching). The polymer samples included high‐ and low‐density polyethylenes with different molecular weight distributions (wide, medium, unimodal, and bimodal) from nine producers. The results were tested against the melt flow index and zero‐shear melt viscosity to find correlations. The data for high‐density polyethylene correlated well with the molecular weight, whereas the data for low‐density polyethylene did not correlate. However, when the weight‐average molecular weight was corrected by the branching parameter and a factor form, all the polyethylene samples fit a single equation. These results indicate that the melt flow index is dependent not only on the molecular weight but also on the molecular shape, including branching. The relation accounted for samples of different resin producers, molecular weights (65,000–638,000), and polydispersities (2.9–20). The use of the branching parameter for the correction of the molecular weight allowed the correlation of these parameters despite differences in the technologies, molecular weights, and molecular architectures. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1572–1578, 2007
Thermomechanical history effects on rigid PVC microstructure and impact properties
Authors: Fillot Louise‐Anne , Hajji Philippe , Gauthier Catherine , Masenelli‐Varlot Karine 
Published: February 2007

AbstractRigid PVC microstructure strongly depends on processing conditions: under both shear and heat influence, gelation process occurs, and the resulting morphology can be characterized by the so‐called gelation level parameter. But thermomechanical history also affects several other features of the microstructure. In this work, two different aspects mainly related to (i) orientation and (ii) molecular mobility are pointed out, and their respective effects on poly(vinyl chloride) (PVC) impact properties are described. Charpy impact tests have been carried out on a typical extruded window profile formulation, evidencing a strong anisotropy effect in those extrudates. It turned out that modulated differential scanning calorimetry was able to evidence macromolecular orientation. Then, the effects of heat treatments on impact properties were investigated. Below the glassy transition temperature (Tg) of PVC, physical ageing results in a decrease of the impact performance, without affecting PVC anisotropy. The reason of this performance loss is the reduction of the molecular mobility, as evidenced by dynamical mechanical analysis experiments. After performing a heat treatment above Tg, another important decrease of the impact performance was observed. This decrease was attributed to (i) partial disorientation of the PVC macromolecular chains and (ii) reduction of the molecular mobility. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2009–2017, 2007
Synthesis and evaluation of novel light‐curable amino acid‐constructed glass–ionomer cements
Authors: Xie Dong , Park Jong‐Gu , Faddah Mona 
Published: February 2007

AbstractPoly(alkenoic acid)s constructed with β‐alanine and glutamic acid were synthesized and grafted with glycidyl methacrylate (GM). The purified polymers were further formulated with water, acrylic acid (AA), and Fuji II LC glass filler to form photocurable dental cements. Compressive strength (CS) and flexural strength (FS) of the cement, and viscosity of the resin liquid were used as screening tools to find the optimal formulation. The specimens were conditioned in distilled water at 37°C for 24 h, prior to testing. The results show that the effects of grafting ratio, polymer content, powder liquid (P/L) ratio, initiator concentration, and light exposure time were significant, but the effect of molecular weight was not. Aging study shows that the experimental cement showed a constant increase in mechanical strength for up to 1 week and then kept constant over 1 month. The formulation with 50/25/25 (liquid composition of polymer/AA/water), 70% (grafting ratio of GM), 3.2/1 (P/L ratio) as well as 0.9% (camphorquinone) and 1‐min light exposure time were found to be the optimal. The experimental cement was 19% higher in CS, 47% higher in diametral tensile strength and 176% higher in FS, compared to Fuji II LC. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1587–1595, 2007
Synthesis and characterization of hindered amine light stabilizers based on end functionalization of polypropylene
Authors: Reddy K. Raghunatha , Kumar Bijendra , Rana Sravendra , Tevtia Amit K. , Singh R. P. 
Published: February 2007

AbstractA polymeric hindered amine light stabilizer (HALS), where HALS moiety was attached at the terminal end of the polypropylene chain via end‐functionalized vinylidine PP through simple organic reactions, was synthesized. It comprises the synthesis of vinylidine‐terminated polypropylene by using Cp2ZrCl2/MAO as catalyst system and epoxidation of vinylidene polypropylene. The final product was synthesized by carrying out the reaction between epoxy end functionalized polypropylene and 4‐amino‐2,2,6,6‐tetrametyl piperidine. The final product was characterized by using 1H NMR, 13C NMR, and FT‐IR spectra. Functionality was calculated by using vapor phase osmometry and 1H NMR. The solubility and diffusion coefficient of the product were calculated and also its stabilization performance was checked. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1596–1602, 2007
A study of some equation‐of‐state parameters of poly(methylhydrosiloxane‐co‐dimethylsiloxane) with some solvents by gas chromatography
Authors: Coskun Selin , Cankurtaran Özlem , Eran Belkis B. , Sarac Ayfer 
Published: February 2007

AbstractTrace amount of methyl acetate, ethyl acetate, tert‐butyl acetate, pentane, hexane, and heptane were passed through the chromatographic column loaded with poly(methylhydrosiloxane‐co‐dimethylsiloxane) coated on Chromosorb W. The retention diagrams of the solvents on the copolymer were plotted by means of specific retention volumes at temperatures between 40 and 80°C by inverse gas chromatography technique. In this study, some thermodynamic interaction parameters such as Flory–Huggins polymer–solvent interaction parameter, equation‐of‐state polymer–solvent interaction parameter, effective exchange energy parameter, and weight fraction activity coefficients at infinite dilution of the solvent were determined. Then, the exchange enthalpy parameter and entropy parameter were determined by using a relation for the enthalpy interaction parameter of the equation‐of‐state theory, which is arranged for the inverse gas chromatography conditions. Later, the partial molar heat of sorption and the partial molar heat of mixing were obtained. The solubility parameter of this copolymer was determined as 6.64 (cal/cm3)1/2 at room temperature. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1627–1631, 2007
Poly(lactide) nanofibers produced by a melt‐electrospinning system with a laser melting device
Authors: Ogata Nobuo , Yamaguchi Shinji , Shimada Naoki , Lu Gang , Iwata Toshiharu , Nakane Koji , Ogihara Takashi 
Published: February 2007

AbstractA new melt‐electrospinning system equipped with a CO2‐laser melting device was developed. Rod‐like samples were prepared from poly(lactide) pellets, and then fibers were produced from the samples using the new system. The effects of producing conditions on the fiber diameter were investigated. Furthermore, the physical properties of the fibers were investigated. The following conclusions were obtained: (i) in a special case, fibers having an average fiber diameter smaller than 1 μm could be obtained using the system developed; (ii) the fiber diameter could be decreased with increased laser output power, but the physical properties of the fibers such as the melting point and the molecular weight were decreased; and (iii) the electrospun fibers exhibited an amorphous state, and the annealed fibers exhibited an isotropic crystal orientation. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1640–1645, 2007
Preparation of super‐hydrophobic film with fluorinated‐copolymer
Authors: Chang Kuei‐Chien , Chen Hui , Huang Chih‐Kai , Huang Shi‐Ing 
Published: February 2007

AbstractOrganic superhydrophobic films were prepared by utilizing TA‐N fluoroalkylate (TAN) and methyl methacrylate (MMA) copolymer as water‐repellent materials and inorganic silica powder as surface roughness material has been developed. Coating solutions prepared by adding silica powders into copolymer solution directly (one‐step method) and by adding silica powders into monomers and allowing them to react (two‐step method). The results showed that contact angles of the films prepared by one‐step method (37.6 wt % of silica powders in the coating solution) were greater than 150°, but the transmittance of the film at visible light was only 30%. On the other hand, the contact angle of films prepared by two‐step method (20 wt % of silica powders in the coating solution) was greater than 160° and the transmittance of the film was greater than 90%. The contact angle of the film prepared by poly(octyl acrylate), POA, was 32.1°, but while introducing silica powder into the system, the contact angle of the film was reduced to be smaller than 5°. Thus, superhydrophobic and superhydrophilic films can be obtained by introducing a roughening material on the hydrophobic surface and the hydrophilic surface, respectively. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1646–1653, 2007
Glass‐transition‐temperature depression in chemically crosslinked low‐density polyethylene and high‐density polyethylene and their blends with ethylene vinyl acetate copolymer
Authors: Khonakdar H. A. , Jafari S. H. , Hässler R. 
Published: February 2007

AbstractA reduction in the glass‐transition temperature (Tg) was found for polyolefins chemically crosslinked by peroxide. This tendency, which was observed for low‐density and high‐density polyethylenes, was also validated for their blends with Ethylene Vinyl Acetate copolymer. It is proposed that the constrained crystallization process, as a result of a restriction imposed on the chain packing by the chemical crosslinks, results in an increasing net free volume in the amorphous phase and hence reduces Tg. The Tg depression becomes greater with increasing crosslink density, whereas at the same time, the degree of crystallinity and consequently the density of the system decreases with an increase in the peroxide content. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1654–1660, 2007
Styrene/tetradecyl methyl acrylate/3‐methacryloxylpropyl trimethoxyl silane triblock copolymers: Atom transfer radical polymerization synthesis and effects on the glass‐fiber/polypropylene interphase properties as a macromolecular coupling agent
Authors: Zhou Shanhua , Gao Yan , Wang Yantao , Hu Chunpu , Dong Qingzhi 
Published: February 2007

AbstractStyrene/tetradecyl methyl acrylate/3‐methacryloxylpropyl trimethoxyl silane triblock copolymers (PSTKs), with well‐defined structures and narrow molecular weight distributions, were synthesized by atom transfer radical polymerization. They were investigated as macromolecular coupling agents for the surface treatment of glass fibers. The reaction kinetics for the triblock copolymers were studied. The contact angles of the copolymers with water and diiodomethane showed that a modified‐glass‐fiber surface treated with a PSTK solution had strong hydrophobicity and that the impregnation of polypropylene on glass fibers was improved dramatically. In comparison with a film of 3‐methacryloxylpropyl trimethoxyl silane, the polarity of the surface free energy of a PSTK film decreased, whereas the dispersion increased greatly. The critical concentration of the macromolecular coupling agents was obtained, and the monolayer saturated adsorptive capacity was calculated with the Gibbs absorption isotherm equation. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1661–1670, 2007
Reactive‐extrusion route for the closed‐loop recycling of poly(ethylene terephthalate)
Authors: Kiliaris P. , Papaspyrides C. D. , Pfaendner R. 
Published: February 2007

AbstractThe effectiveness of the reactive extrusion technique was investigated for poly(ethylene terephthalate) to promote the concept of closed‐loop recycling, that is, the reuse of waste material in the initial application. More specifically, a chain‐extender system, consisting of pyromellitic dianhydride, polyol, and a catalyst, was employed, and its efficiency regarding the improvement of the recyclate quality was evaluated. Accordingly, rheological and thermal characterizations were performed and used as criteria of the modification induced in the polymer molecular structure during processing due to the counteracting degradation and chain‐extension reactions. In particular, the molecular weight, related to intrinsic viscosity and melt flow rate measurements, of modified poly(ethylene terephthalate) samples was found to increase with the additive content. Simultaneously, a decrease in the crystallinity was observed, attributed to the branching effect of the chain extender, which restricted the ability of the macromolecules to organize in the crystal structure. Beyond a critical concentration of the additive system, the molecular weight of the treated samples started to decrease again, and this was accompanied by a small increase in the crystallinity. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1671–1678, 2007
Effect of curing moisture on the indentation force deflection of flexible polyurethane foam
Authors: Ni Haifeng , Yap Chee Keong , Jin Yan 
Published: February 2007

AbstractThe moisture effect on the indentation force deflection (IFD) of flexible polyurethane foam was examined through the curing of the foam with different moisture contents. The employed foam was cured at 30, 40, 50, 60, 70, and 80% relative humidity, and the corresponding curing temperature was constant at 23°C. The experiments showed that the measured IFD and support factor of the flexible polyurethane foam decreased, and the hysteresis increased with the curing moisture. A statistical conversion formula was generated experimentally to correct the measured IFD of the flexible polyurethane foam to eliminate the deviation caused by the moisture effect. The measured IFD was inversely exponentially proportional to the curing moisture. The accuracy of the correction formula was verified by the conditioning of the foam again with different moisture contents. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1679–1682, 2007
Tensile properties of hollow glass bead‐filled polypropylene composites
Authors: Liang Ji‐Zhao 
Published: February 2007

AbstractThe tensile properties of polypropylene (PP) filled with hollow glass beads have been measured at room temperature to identify the effects of the particle contents, size and its distribution on them in the present article. The mean diameters of the fillers were 11, 35, and 70 μm, and they were named as TK10, TK35, and TK70 respectively. The surface of these particles was pretreated with silane coupling agent. The results showed that the yield stress (σy) decreased gently for PP/TK70 systems, whereas decreased relatively obviously for PP/TK35 systems with increasing the volume fraction (ϕf) of the fillers. When ϕf was less than 5%, the tensile strength at break (σb) of the composites increased with the increase of ϕf. When ϕf was more than 5%, σb was almost a constant for PP/TK70 systems, while σb decreased linearly for PP/TK35 systems. The tensile fracture strain (εb) of the composites decreased suddenly when ϕf was less than 5%, and then decreased slightly with increasing ϕf. When ϕf was 10%, σy and σb increased while εb decreased with the increase of the bead diameter. Furthermore, the σy was predicted by means an equation proposed in the previous work, and good interfacial adhesion was shown between the hollow glass beads and the matrix. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1697–1701, 2007
Effect of metal ions and pH values on the conformational transition of the copolymer chain in aqueous solutions
Authors: Wang Bin , Liu Mingzhu , Chen Yong , Liang Rui , Chen Shilan , Jin Shuping 
Published: February 2007

AbstractA novel salts‐ and pH‐responsive copolymer, poly(acrylic acid‐co‐ethyl 1‐(4‐chlorophenyl)‐5‐acrylamino‐1,2,3‐triazol‐4‐carboxylate), poly(AA‐co‐ECATC), was prepared by radical polymerization in methanol at room temperature with L‐ascorbic acid (Vc) and peroxide hydrogen (H2O2) as initiators. The copolymer was characterized by Fourier Transform Infrared (FTIR) spectroscopy and Differential Scanning Calorimetry (DSC). The copolymer possessed excellent fluorescence properties. The effects of metal ions with different charges, radius and outer‐layer electron constructions and pH values on the conformation transition of copolymer chains were systematically investigated by the fluorescence intensity and the fluorescence anisotropy. It was found that fluorescence intensity and fluorescence anisotropy curves waved with the change of metal ions concentrations and pH values. Additionally, FTIR Subtraction spectroscopy was also carried out to confirm our results. The work provided a theory basis for the study of salts‐ and pH‐sensitive smart hydrogels, which were always used in the slow‐ or controlled‐release drugs. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1714–1722, 2007
Mechanical and electrical properties of hydrous electrorheological elastomers based on gelatin/glycerin/water hybrid
Authors: Gao Lingxiang , Zhao Xiaopeng 
Published: February 2007

AbstractAimed at improving the stability of geometrical shape, mechanical performance, and particles dispersion of electrorheological (ER) hydrous elastomers, a new gelatin water‐based elastic gels containing starch particles were prepared under an applied dc electric field, and their ER effects were described with the compression modulus and the electric resistivity. The result demonstrates that the mechanical and electrical properties of the ER elastomers are dominated by an externally applied electric field as well as the weight fraction of particles. On comparing with the same chemical composition, elastomers cured without a field and with barium titanate/gelatin water‐based elastomer, some conclusions are suggested: the object elastomer has stronger responses to a field than the same chemical composition elastomer, especially with higher weight fractions of particles. The object elastomer has steady geometrical shape and mechanical performance because of the addition of glycerin into the matrix, and has a better dispersion of particles. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1738–1743, 2007
Synthesis and properties of organic soluble semicrystalline poly(aryl ether ketone)s copolymers containing phthalazinone moieties
Authors: Sun Qingmin , Wang Jinyan , He Lishan , Song Yuan , Jian Xigao 
Published: February 2007

AbstractA series of poly(aryl ether ketone)s (PAEK) copolymers containing phthalazinone moieties were synthesized by modest polycondensation reaction from 4‐(4‐hydroxyl‐phenyl)‐(2H)‐phthalazin‐1‐one (DHPZ), hydroquinone (HQ), and 1,4‐bis(4‐fluorobenzoyl)benzene (BFBB). The Tg values of these copolymers ranged from 168 to 235°C, and the crystalline melting temperatures varied from 285 to 352°C. By introducing phthalazinone moieties into the main chain, the solubility of these copolymers was improved in some common polar organic solvents, such as chloroform (CHCl3), N‐methyl‐2‐pyrrolidinone (NMP), nitrobenzene (NB) and so on. The values of 5% weight loss temperatures were all higher than 510°C in nitrogen. The crystal structures of these copolymers were determined by wide‐angle X‐ray diffraction (WAXD), which revealed that they were semicrystalline in nature, and the crystal structure of these copolymers was orthorhombic, equal to poly(ether ether ketone ketone)s. As phthalazinone content in the backbone varied from 0 to 40 mol % (mole percent), the cell parameters of these copolymers including the a, b, and c axes lengths ranged from 7.76 to 7.99 Å, 6.00 to 6.14 Å, and 10.10 to 10.19 Å, respectively. The degree of crystallinity (via differential scanning calorimetry) decreased from 37.70% to 16.14% simultaneously. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1744–1753, 2007
Compression‐molded, lubricant‐treated UHMWPE composites
Authors: Puukilainen Esa , Saarenpää Hanna , Pakkanen Tapani A. 
Published: February 2007

AbstractLubricant‐treated ultra high molecular weight polyethylene (UHMWPE) composites were prepared by compression molding. Composites were made from mixtures containing up to 5.0 wt % of lubricant. Two solid lubricants, molybdenum disulfide (MoS2), and carbon black (CB), and one liquid lubricant, perfluoropolyether (PFPE), were used in the study. UHMWPE and the lubricants formed 3D networks, where the lubricant was evenly spread over the UHMWPE particles. The amounts of MoS2 and CB were determined by thermogravimetric analyses, and the amounts of PFPE by ATR‐IR spectroscopy. All the lubricant treated composites showed better friction properties than pure UHMWPE. The addition of PFPE to UHMWPE improved the hydrophobicity of the surface, whereas the addition of solid lubricant had little effect. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1762–1768, 2007
Removal of environmentally impacting metal ions using functional resin poly(4‐styrene sulfonate‐co‐4‐vinylpyridine): Synthesis and metal ion retention properties
Authors: Rivas Bernabé L. , Muñoz Carla 
Published: February 2007

AbstractA water‐insoluble polymer, poly(sodium 4‐styrene sulfonate‐co‐4‐vinylpyridine), was synthesized by radical polymerization at different amounts (2, 4, 6, and 8 mol %) of crosslinking reagent (CR). The polymerization yield ranged from 83.5% to 100.0%. The resin is characterized by FT IR spectroscopy, thermal analysis, and scanning electron microscopy. The water absorption capacity, WAC (110 g/g dry resin), was obtained for the resin with a 2 mol % of CR. The metal ion affinity is studied by Batch equilibrium procedure under different experimental conditions for the cations: Hg(II), Cd(II), Zn(II), Pb(II), Cr(III), and Al(III). The metal ion affinity increased as the pH increased. At pH 5, the resin presented an affinity above 90% for all metal ions. Hg(II) presented the highest retention value at pH 2. The maximum metal ion retention capacity is determined at optimum pH for Hg(II), Cd(II), Pb(II), and Zn(II). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1769–1774, 2007