bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation and properties of polyethylene–clay nanocomposites by an in situ graft method
Authors: Qi Rongrong , Jin Xing , Zhou Chixing 
Published: September 2006

AbstractThe polyethylene–clay nanocomposites were prepared by the in situ graft copolymerization of styrene containing twin‐benzyldimethyldioctadecylammonium bromine modified montmorillonite (TBDO‐MMT) in polyethylene with dicumyl peroxide (DCP) as an initiator in molten state. XRD and TEM analysis indicated that intercalated polyethylene/MMT nanocomposites are obtained. The mechanics performance, crystal behavior, thermal properties, and the effect of MMT contents on PE/MMT nanocomposite were also studied. As comparison, polyethylene/montmorillonite composites prepared by a simply melt compounding without styrene were studied as well. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4921–4927, 2006
Characterization of the biocide polyhexamethylene biguanide by matrix‐assisted laser desorption ionization time‐of‐flight mass spectrometry
Authors: O'Malley Leon P. , Hassan Kaneez Z. , Brittan Helen , Johnson Neil , Collins Andrew N. 
Published: September 2006

AbstractThe biocide polyhexamethylene biguanide (PHMB) has been characterized by matrix‐assisted laser desorption ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS). Previously, no method has been able to provide a detailed structural characterization of PHMB. MALDI‐TOF MS was able to detect PHMB oligomers with n ≤ 6. Six different PHMB product types were identified, which possess combinations of amine, cyanoamine, guanidine, or cyanoguanidine end‐groups. Postsource decay (PSD) fragmentation was used to confirm the correct assignment of PHMB structure for the dominant PHMB molecular ion. MALDI‐TOF MS analysis of a 15N‐labeled PHMB confirmed the correct assignment of PHMB molecular ions, and also indicated the existence of a polymerization–depolymerization equilibrium during melt polymerization of the polymer. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4928–4936, 2006
Application of Taguchi method in determining optimum level of curing system of NBR/PVC blend
Authors: Hafezi Mahshid , Khorasani Saied Nouri , Ziaei Farhood 
Published: September 2006

AbstractTaguchi method is applied in this study to determine the optimum level of curing system (sulfur, MBTS, and CBS) in a NBR/PVC blend. By considering physicomechanical properties of cured NBR/PVC blend, optimum level of curing system is determined. A fixed master batch formulation of NBR/PVC is used, and the effect of curing system is studied on the physicomechanical properties of NBR/PVC blend, such as tensile strength (TS) and elongation‐at‐break (EB) before and after aging and also hardness and abrasion. The L9 orthogonal array that includes nine rows and four columns is applied. In this matrix, rows show the experiments and three columns show the amount of three factors (sulfur, MBTS, and CBS) and one column is left arbitrarily as an empty column. In this array, the columns are mutually orthogonal. The optimum physicomechanical properties of cured NBR/PVC blend are at 2 phr sulfur, 2 phr MBTS, and 0.5 phr CBS of curing system. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5358–5362, 2006
Structure–properties relationship in toughening of poly(butylene terephthalate) with core–shell modifier
Authors: Sun S. L. , Xu X. Y. , Tan Z. Y. , Zhou C. , Ao Y. H. , Zhang M. Y. , Zhang H. X. 
Published: September 2006

AbstractThe performance of acrylonitrile–butadiene–styrene (ABS) core–shell modifier with different grafting degree, acrylonitrile (AN) content, and core–shell ratio in toughening of poly(butylene terephthalate) (PBT) matrix was investigated. Results show PBT/ABS blends fracture in ductile mode when the grafting degree is high, and with the decrease of grafting degree PBT/ABS blends fracture in a brittle way. The surface of rubber particles cannot be covered perfectly for ABS with low grafting degree and agglomeration will take place; on the other hand, the entanglement density between SAN and PBT matrix decreases because of the low grafting degree, inducing poor interfacial adhesion. The compatibility between PBT and ABS results from the strong interaction between PBT and SAN copolymer and the interaction is influenced by AN content. Results show ABS cannot disperse in PBT matrix uniformly when AN content is zero and PBT/ABS fractures in a brittle way. With the addition of AN in ABS, PBT/ABS blends fracture in ductile mode. The core–shell ratio of ABS copolymers has important effect on PBT/ABS blends. When the core–shell ratio is higher than 60/40 or lower than 50/50, agglomeration or cocontinuous structure occurs and PBT/ABS blends display lower impact strength. © 2006 Wiley Periodicals, Inc. J Appl PolymSci 102: 5363–5371, 2006
Thermal stability and chemical durability of PVC‐based biomedical devices
Authors: Manfredini Matteo , Bodecchi Lidia M. , Marchetti Andrea 
Published: September 2006

AbstractPoly(vinyl chloride) (PVC)‐based blood circuits for extracorporeal hemodialysis were investigated for the assessment of their thermal stability as well as their chemical durability towards ionizing radiation sterilization and environmental conditions of storage and transportation. Thermal degradation was monitored by measuring the amount of hydrochloric acid (HCl) evolved as a function of different thermal stresses. HCl was extracted from the internal lumen of the blood circuits, and then quantitatively evaluated under the corresponding form of chloride ions by chromatographic technique (HPLC‐IC). Behavior of PVC heat stabilizers was evaluated as well, determining also the concentration of calcium and zinc released by the investigated materials, by flame atomic absorption spectroscopy (FAAS) technique. Electron beam irradiation revealed an impact on blood tubing higher than that of environmental storage conditions. Nevertheless, real operative cases of sterilization and storage conditions turned out to be quite safe, and all blood circuits displayed good performances in terms of thermal stability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:5378–5387, 2006
Morphology and characterization of conductive films based on polyaniline‐coated polystyrene latexes
Authors: Liau Wen‐Bin , Sun Yu‐Ting , Yang Ling‐Yueh , Wang Lee‐Yih , Chiu Wen‐Yen , Hsieh Kuo‐Huang , Tseng Sheng‐Mao 
Published: September 2006

AbstractThe polyaniline (PANI)‐coated polystyrene (PS) latexes were synthesized, and the electrically conductive films were prepared thereafter. The weight ratio of PANI was 5%. Thermal analysis of the latices was performed using DSC and TGA. In this study, the electrically conductive films were prepared above the PS glass transition temperature (Tg). During the film formation, the effects of the annealing temperature and atmosphere (air or N2) on the film resistance were investigated. In addition, the film morphology was observed utilizing scanning electron microscopy. The film resistance decreased in the initial heating stage due to the increasing temperature and the compaction of film. Then the film resistance increased with further annealing due to the aging of PANI. Typically, the film resistance was about 6000 Ω/sq, and the conductivity was 0.3 S/cm. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5406–5413, 2006
High thermal conductivity epoxy molding compound filled with a combustion synthesized AlN powder
Authors: Hsieh Cheng‐Yu , Chung Shyan‐Lung 
Published: September 2006

AbstractA combustion synthesized AlN powder was studied for its feasibility as a filler for epoxy molding compound (EMC) and effects of various experimental parameters on the thermal conductivity and moisture resistance of the EMC were investigated. The AlN powder was coated with silane both to increase the moisture resistance of the EMC and to enhance the bonding between the filler AlN and the matrix resin. The thermal conductivity could be significantly increased by using AlN powders with large particle sizes and this was considered to be due to a reduction in interface area between the AlN particles and the matrix resin. A thermal conductivity of 14 W/mK was obtained when the EMC was fabricated by a process involving no use of a solvent and a AlN powder with a particle size of 35.3 μm and a filler content of 67 vol % were used. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4734–4740, 2006
Rigidity of heat‐treated oriented isotactic polypropylene
Authors: Tsobkallo Katherina , Tikhomirov A. , Bozdogan A. , Tshmel A. 
Published: September 2006

AbstractUniaxially oriented commercial films of isotactic polypropylene were strained with ends keeping fixed and subjected to the heat treatment at temperatures from 50 to 200°C. The rigidity of annealed samples was characterized by the value of tangent modulus, Et, determined graphically at the initial portions of stress–strain curves. The structural changes in the samples were studied with the help of the IR and low‐frequency Raman spectroscopies. The smallest Et values were obtained for the low‐strained films, while the tangent moduli measured for highly strained samples exceeded the value for the original (untreated) film. The most prominent positive effect was achieved after annealing the samples at 90°C. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 6074–6080, 2006
Naphthoic acid derivatives as hydrogen bond donors in supramolecular materials
Authors: Riedel Paul J. , Kumpfer Justin R. , Rogness Donald C. , Wiegel Kurt N. 
Published: September 2006

AbstractThe synthesis of a series of 6‐hydroxy‐2‐naphthoic acid derivatives is described. These have been used to form supramolecular main‐chain liquid crystalline polymers. These hydrogen bond donors are complexed with a series of bisfunctionalized rigid pyridine species. These associative chain structures were analyzed through differential scanning calorimetry and polarizing light thermal optical microscopy. The liquid crystalline phases formed displayed mainly enantiotropic nematic phases that display an increase in clearing temperature as the rigid portions of the supramolecular system increased in length. A decrease in the clearing temperature was observed as the length of the flexible spacer group increased. Both of these observations follow established trends in liquid crystalline behavior. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5890–5894, 2006
Synthesis of poly(vinyl propionate) from poly(vinyl alcohol) in nonaqueous medium using ethyl nitrate dimethyl sulfoxide as a catalyst
Authors: Chetri Prafulla , Dass Narendra N. , Sarma Neelotpal Sen 
Published: September 2006

AbstractPoly(vinyl alcohol) (PVA) can be dissolved in a nonaqueous medium in the presence of catalytic concentration of ethyl nitrate dimethyl sulfoxide, C2H5ONO2·DMSO. From the PVA solution, poly(vinyl propionate), PVPR was prepared by the homogeneous esterification of PVA with propionic acid. The ester thus formed contained some unconverted hydroxyl group. The formation of the ester was confirmed by the IR and 1H‐NMR spectra. The molecular weight of the ester was determined by GPC and intrinsic viscosity (η) was determined by viscometric method. Glass transition temperature, Tg, was obtained from differential scanning calorimetric (DSC) analysis. Thermal stabilities of the ester were checked by thermogravimetric analysis (TGA) and differential thermogravimetric (DTG) analysis. The efficiency of the ester as a flow improver of crude oil was also examined. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5675–5679, 2006
Synthesis and photopolymerization of ethylene glycol 3‐morpholine‐propionate methacrylate for potential dental composite application
Authors: Wu G. Q. , Shi S. Q. , Xiao P. , Nie J. 
Published: September 2006

Abstract2,2‐Bis[4‐(2‐hydroxy‐3‐methacryloxypropoxy) phenyl]‐propane (bis‐GMA), triethylene glycol dimethylacrylate (TEGDMA), camphorquinone (CQ), ethyl‐4‐dimethylaminobenzoate (EDMAB), or 2‐(dimethylamine)ethyl methacrylate (DMEM) were composed of the modern dental composite system and acted as resin, diluent, photoinitiator, and coinitiator, respectively. In this study, ethylene glycol 3‐morpholine‐propionate methacrylate (EGMPM) was synthesized via Michael addition reaction to replace both the TEGDMA as a diluent and the nonpolymerizable amine EDMAB as a coinitiator. Mixtures of bis‐GMA/TEGDMA/CQ/EGMPM and bis‐GMA/TEGDMA/CQ/DMEM were found to have almost the same rate of polymerization and reach final double bond conversion at 58%, slightly lower than that of the bis‐GMA/TEGDMA/CQ/EDMAB (63%) and bis‐GMA/EGMPM/CQ (60%) under comparable visible light irradiation conditions. In addition, the results of dynamic mechanical analysis showed that all of the four samples had approximately the same modulus and the glass transition temperature. The water sorption and solubility of bis‐GMA/TEGDMA/CQ with different amines (EDMAB, DMEM, and EGMPM) had almost the same value except that the water sorption of bis‐GMA/EGMPM/CQ was out of the range of the ISO 4049 (2000) standards. The results indicated that EGMPM was potentially a coinitiator for dental composite, because there are no significant differences in photopolymerization characteristic and physical properties when compared with traditional system (bis‐GMA/TEGDMA/CQ/EDMAB). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4589–4594, 2006
Simultaneous novel synthesis of conducting, nonconducting, and crosslinked polymers by microwave initiation
Authors: Bayraklı Çelik Güler , Kısakürek Duygu 
Published: September 2006

AbstractA novel synthesis of poly(dibromophenylene oxide) (P), conducting polymer (CP), and/or crosslinked polymer (CLP), and/or radical ion polymers (RIP) was achieved simultaneously from sodium 2,4,6‐tribromophenolate by microwave energy in a very short‐time interval. The synthesized polymers were characterized via elemental analysis, FTIR, 1H NMR and 13C NMR, X‐ray diffraction spectroscopy, SEM, DSC, TGA, ESR, GPC, conductivity measurement, and light scattering. It was found that polymerization proceeds through both 1,2‐ and 1,4‐addition at equal rates. The effects of the energy and time on the % conversion and the polymer synthesis were investigated. The optimum condition for synthesis of P (the highest Mw, 2.97 × 105 g/mol) and CP was 70 W for 5 min in 5 mL water and 100 W for 1 min in 0.5 mL water, having maximum values 23.6% and 27.2%, respectively. In addition, synthesis of CLP and RIP were achieved in 5 mL water at 350 W and 700 W at the end of 1 min, respectively. The direct synthesis of highly conducting polymer, with the conductivity of 1 S cm−2 was achieved in the absence of applied doping process in a very short time sequence. P, CP, CLP, and RIP had fine granular, sponge‐like, dendrite, and coarse surface structures, respectively. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:5427–5435, 2006
Supported titanium–magnesium catalysts with different titanium content: Kinetic peculiarities at ethylene homopolymerization and copolymerization and molecular weight characteristics of polyethylene
Authors: Echevskaya Ludmila G. , Matsko Mikhail A. , Mikenas Tatiana B. , Nikitin Valentin E. , Zakharov Vladimir A. 
Published: September 2006

AbstractThe effect of Ti content on the activity of titanium–magnesium catalysts (TMC) and molecular weight distribution (MWD) of polyethylene (PE) produced has been studied. It was found that the activity enhances sharply as Ti content decreases from 0.6 to 0.07 wt %, and shows no significant changes in the Ti content range of 0.6–5.0 wt %. The maximum activity (36 kg PE/mmol Ti × h × bar C2H4) was observed for TMC with the lowest Ti content. The catalyst with low titanium content (∼ 0.1 wt % of Ti) produced PE with narrower MWD (Mw/Mn = 3.1–3.5) as compared to catalysts with higher titanium content (3–5 wt % of Ti; Mw/Mn = 4.8–5.0). New data on the effect of hydrogen on MWD of PE have been found. Increasing hydrogen concentration results in broadening the MWD of PE, especially in the case of TMC with high titanium content. The data presented indicate the heterogeneity of active centers of TMC in the reaction of chain transfer with hydrogen. The data on the ethylene–hexene‐1 copolymerization over TMC with different titanium content are presented. Comonomer reactivity ratios were shown to be independent of the Ti content in TMC. Presumably the difference in activity of these catalysts is mainly caused by the difference in the number of active centers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:5436–5442, 2006
Electrospinning of chitosan/poly(vinyl alcohol)/acrylic acid aqueous solutions
Authors: Zhou Yingshan , Yang Dongzhi , Nie Jun 
Published: September 2006

AbstractChitosan bicomponent fibers were prepared via the electrospinning of chitosan/poly(vinyl alcohol)/acrylic acid aqueous solutions with different concentrations. With a 4% acrylic acid aqueous solution, when the chitosan/poly(vinyl alcohol) mass ratios were lower than 80/20, electrospinning nanofibers could be obtained. With a 90% acrylic acid aqueous solution, when the chitosan/poly(vinyl alcohol) mass ratios were less than 95/5, good nanofibers could be electrospun. The average diameter of the nanofibers gradually decreased, and its distribution became narrower as the poly(vinyl alcohol) concentration increased. Chitosan/poly(vinyl alcohol)/acrylic acid aqueous solutions could be electrospun at various concentrations by the adjustment of the chitosan and poly(vinyl alcohol) concentrations. The effects of the viscosity and conductivity of the blend solution on the morphologies of the fiber mats were also investigated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5692–5697, 2006
Morphology and coalescence of ethylene copolymers: Influence of thermal treatments and sorbitol nucleating agents
Authors: Lin W. , Bellehumeur C. T. 
Published: September 2006

AbstractCoalescence of polymer particles is a key phenomenon in many powder processing technologies. Both the extent and the rate of coalescence between particles govern the production cycle and the performance of the end‐product. It is well accepted that both processing conditions and material formulation affect the morphology of molded parts and consequently their mechanical properties. The interest of this study is to evaluate the impact that changes in morphological features caused by the imposition of different thermal treatments as well as by the addition of a nucleating agent (bis 3,4 dimethylbenzylidene sorbitol) have on the coalescing behavior of ethylene copolymers produced from Ziegler–Natta and metallocene catalyst technologies. Results showed that samples produced using slower cooling rates exhibited higher crystallinity and increased thermal stability. Variations in thermal treatments, however, only resulted in minor changes in the coalescing behavior of the resins considered in this work. However, the addition of the nucleating agent to Ziegler–Natta ethylene copolymers led to the formation of crystalline structures with increased material thermal stability, but reduced chain mobility, and consequently resulted in a slower coalescing rate. These effects, however, are dependent on the molecular structure of the copolymers. The addition of the sorbitol nucleating agent influenced the morphological structure of the metallocene copolymer used in this work but did not result in any significant changes in the coalescence behavior of the resin. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5443–5455, 2006
Thermal stability of structural one‐component polyurethane adhesives for wood—structure‐property relationship
Authors: Richter K. , Pizzi A. , Despres A. 
Published: September 2006

AbstractThe relationship between the chemical structure of commercial polyurethanes and temperature‐dependent creep properties was determined in full scale tests and the results were compared with thermomechanical analysis. Comparison of mechanical performance with 13C‐NMR spectroscopy studies elucidated important structure‐property relationships, which either allow the reduction or elimination of temperature‐dependent creep in one‐component polyurethanes (1C‐PUR) adhesives for wood. The combination of the relative content of still reactive, free NCO groups on the polyurethane, careful selection of the degree of resin polymerization and a slower rate of reaction are the three most significant parameters that have to be controlled to overcome the problem of temperature‐dependent creep found in 1C‐PUR adhesives. The results obtained indicate that adhesives presenting a combination of a higher content of still unreacted NCO groups, a lower degree of polymerization and slower reaction rate are capable to counteract problems of high sensitivity of polyurethane to temperature‐dependent creep. Two commercial polyurethanes that fulfil the latter requirements and exhibit almost no creep were identified and characterized. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5698–5707, 2006
Modeling the morphology development of ethylene copolymers in rotational molding
Authors: Xu H. , Bellehumeur C. T. 
Published: September 2006

AbstractA model is proposed to describe the solidification and crystallization phenomena in rotational molding. To capture the morphology development with crystallization behavior, a two‐dimensional theoretical simulation was carried out, consisting of a phase‐field model emphasizing the metastability of polymer crystallization and a heat‐transfer model describing the molding cycle. The model parameters were experimentally evaluated with differential scanning calorimetry and isothermal crystallization tests. Molding trials were also conducted with bench‐scale rotational molding equipment, and the cross sections of the molded products were examined under polarized light optical microscopy. The model predictions capture the formation of transcrystalline structures near the mold surface, which is more apparent under moderate cooling conditions. Our results show that the model predictions are in general agreement with the experimental results obtained in our laboratory as well as those presented in the literature. Because morphological features are important contributing factors to product performance, the model will be useful for the formulation of new materials and process optimization. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5903–5917, 2006
Thermal conductivity of carbon fiber/liquid crystal polymer composites
Authors: Keith Jason M. , King Julia A. , Miller Michael G. , Tomson Amanda M. 
Published: September 2006

AbstractThermally conductive resins are needed for bipolar plates in fuel cells. Currently, the materials used for these bipolar plates often contain a single type of graphite in a thermosetting resin. In this study, varying amounts of two different types of polyacrylonitrile based carbon fibers, Fortafil 243 and Panex 30, were added to a thermoplastic matrix (Vectra A950RX Liquid Crystal Polymer). The resulting single filler composites were tested for thermal conductivity and a simple exponential thermal conductivity model was developed for the square root of the product of the in‐plane and through‐plane thermal conductivity
$\sqrt{k_{\rm in}k_{\rm thru}}$. The experiments showed that the through‐plane thermal conductivity was similar for composites up to 40 vol % fiber. However, at higher loadings, the Panex 30 samples exhibited higher thermal conductivity. The experiments also showed that the in‐plane thermal conductivity of composites containing Panex 30 was higher than those containing Fortafil 243 for all volume fractions studied. Finally, the model agreed very well with experimental data covering a large range of filler volume fraction (from 0 to 55 vol % for both single filler systems). The model can be used with existing through‐plane thermal conductivity models to predict in‐plane thermal conductivity. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5456–5462, 2006