bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermomechanical analysis of the biaxially drawn ultrahigh molecular weight polyethylene‐reinforced polyether polyurethane
Authors: Tang Zheng Gui , Teoh Swee Hin 
Published: January 2004

AbstractTo understand the thermal fusion and interaction of porous polyurethane composites, the thermomechanical profiles of the heat‐compacted composites were described and explained in line with differential scanning calorimetry analysis, FTIR‐ATR interpretation, and morphological observations of the oriented ultrahigh molecular weight polyethylene (UHMWPE) under polarized light transmission. The results indicated that the as‐cast polyurethane composites are porous and can be consolidated in heat compaction. The consolidated polyurethane composites displayed no thermal contraction in the thermomechanical analysis. Two polyurethane materials, Toyobo TM5 and Tecoflex 80A, were selected for the study. The differences between aromatic and aliphatic polyurethane composites were significant. Aromatic polyurethane composites exhibited characteristic thermal fusion, resulting in a uniform heat‐compacted specimen that synergized the thermomechanical advantages of the polyurethane. This thermal fusion led to constraints of UHMWPE and recrystallization of both UHMWPE and polyurethane. The synergized polyurethane composite demonstrated superior resistance to thermal degradation, observed in both the individual UHMWPE and aromatic polyurethane. Thermomechanical analysis supported the recommendation of using the specific heat compaction at 115°C. This process rendered the aromatic polyurethane composite of highly thermomechanical stability, in agreement with previous findings related to optical transparency and tensile properties. The thermomechanical responses of the composite also provided detailed information about the differences between two samples of similar optical transparency and therefore led to the definition of the synergistic structural composite, a void‐free composite with clear evidence. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3088–3095, 2004
Interaction between wood and polyvinyl acetate glue studied with dynamic mechanical analysis and scanning electron microscopy
Authors: Backman A. C. , Lindberg K. A. H. 
Published: January 2004

AbstractThe long‐term properties of bonds are those that are of special interest. To achieve good bonds, the wood polymers and the adhering polymers must be compatible. This paper describes studies of the interaction of wood (Pinus sylvestris) with commercial polyvinyl acetate (PVAc) glue, polymethylmethacrylate (PMMA), and a more hydrophilic acrylate. Interaction was studied with a dynamic mechanical thermal analyzer (DMTA) operating in tensile mode in the tangential direction of wood. DMTA results were correlated with scanning electron microscopy (SEM) fractography studies of adhesion between polymers and wood on a cell wall level. The hypothesis put forward is that a good adhesion on the cell wall level results in a decrease in the glass transition temperature (Tg) measured with DMTA. A decrease in Tg for the hydrophilic acrylate was shown when it was impregnated in wood. The decrease of Tg was correlated with good adhesion to wood on the cell wall level. For PVAc and PMMA no decrease in Tg was measured when glued or impregnated in wood. SEM study also showed that the adhesion on a cell wall level was poor. The results show that DMTA can be a useful technique to study adhesion between wood and glue on a molecular level. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3009–3015, 2004
Effect of acrylate constituent units on the adhesion of polyacrylate sizes to fiber substrates
Authors: Zhu Zhifeng , Qiao Zhiyong , Kang Cuizhen , Li Yuehua 
Published: January 2004

AbstractThe influences of chemical structure of (meth)acrylate monomers, including the carbon atom number of alkyl ester groups and the α‐methyl group, on the adhesion of polyacrylate sizes to all‐polyester, pure cotton, and polyester/cotton blend fiber substrates are investigated by using an impregnated roving method for warp sizing. The adhesion is evaluated in terms of the bonding strength, breaking extension, and work of break of a slightly sized roving. The polyacrylate sizes are prepared through free radical copolymerization of (meth)acrylates with acrylic acid in ethanol. It was found that the adhesion is strongly affected by the structure of acrylate monomers. The adhesion enhances with increasing the carbon atom number of alkyl ester side chains of acrylates, whether or not it is an acrylate or a methacrylate. The α‐methyl does not favor the adhesion to polyester fibers, but favor to polyester/cotton blend fibers. Moreover, the molar ratio of butyl acrylate to acrylic acid is also considered. Excessively lowering the amount of acrylate or acrylic acid damages the adhesion. A favorable molar ratio of butyl acrylate to acrylic acid is found to be about 60 : 40. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3016–3022, 2004
Diffusion and sorption of benzene vapor through polybutadiene‐, polybutadiene/styrene‐, and polybutadiene/acrylonitrile‐based polyurethanes
Authors: Yang Yurun , Huang Yongmin , Chen Yonglin , Wang Dening , Liu Honglai , Hu Chunpu 
Published: January 2004

AbstractA series of polyurethane (PU) films made from toluene diisocyanate (TDI), 1,4‐butanediol (BDO), and hydroxyl‐terminated polybutadiene (HTPB), hydroxyl terminated polybutadiene/styrene (HTBS), or hydroxyl terminated polybutadiene/acrylonitrile (HTBN) was synthesized by solution polymerization. The absorption of benzene vapor was found mainly in the soft phase. The equilibrium adsorption (M∞) was reduced with increasing hard segment content for all the PUs. The values of M∞ were in the sequence of HTBN‐PUs > HTBS‐PUs > HTPB‐PUs, which could be explained by the different interaction parameters between soft segments and benzene. The HTBN‐PU film showed the lowest degree of phase segregation and had more hard segments intermixed in the soft phase, restricting the movement of soft segments, and therefore resulted to non‐Fickian behavior, while the HTPB‐PU is antithetical. FTIR and atomic force microscopy were utilized to identify the hydrogen bonding behavior and morphology change of the PU films before and after the absorption of benzene vapor. The tensile strength of the HTBN‐PUs showed a greater decrease than that of HTBS‐PUs and HTPB‐PUs after absorbing benzene vapor. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2984–2991, 2004
Structure, mechanical, and thermal behavior of nylon 6‐polyisoprene block copolymers obtained via anionic polymerization
Authors: Mateva R. , Filyanova R. , Dimitrov R. , Velichkova R. 
Published: January 2004

AbstractThe structure and physicomechanical properties of nylon 6 (N‐6) modified with polyethylene oxide–polyisoprene–polyethylene oxide (PEO‐PI‐PEO) copolymers via activated anionic polymerization have been investigated by using differential scanning calorimetry (DSC), wide‐angle X‐ray diffraction (WAXD), thermogravimetric analysis (TGA), dynamic mechanical analysis (DTMA), and by optical microscopy. This study deals with the influence that the N‐6/PI ratio and the length of the PI segments have on the physicomechanical behavior, thermal stability, and the structural changes of the block copolymers. Literature does not report on previous investigations of this kind. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3251–3258, 2004
Effect of F/P and OH/P molar ratios and condensation viscosity on the structure of phenol‐formaldehyde resol resins for overlays—A statistical study
Authors: Holopainen Timo , Alvila Leila , Savolainen Pirkko , Pakkanen Tuula T. 
Published: January 2004

AbstractA two‐level full factorial experimental design with three variables, formaldehyde‐to‐phenol (F/P) molar ratio, hydroxyl‐to‐phenol (OH/P) molar ratio, and condensation viscosity was implemented to determine the effect of the variables on the structure of phenol‐formaldehyde resol resins for paper overlay impregnation. Ten resins were prepared with F/P molar ratios between 1.9 and 2.3, OH/P molar ratios between 0.09 and 0.13, and condensation viscosities between 60 and 180 mPa s. The effect of these three independent variables on the chemical structure was analyzed by 13C‐NMR spectroscopy, on the molecular weight distribution by gel permeation chromatography, and on the reactivity by differential scanning calorimetry. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2942–2948, 2004
Hydrogenation of cis‐1,4‐polyisoprene catalyzed by Ru(CHCH(Ph))Cl(CO)(PCy3)2
Authors: Tangthongkul R. , Prasassarakich P. , McManus N. T. , Rempel G. L. 
Published: January 2004

AbstractHydrogenation is a useful method which has been used to improve oxidative and thermal degradation resistance of diene‐based polymers. The quantitative hydrogenation of cis‐1,4‐polyisoprene which leads to an alternating ethylene–propylene copolymer was studied in the present investigation. To examine the influence of key factors on the reaction, such as catalyst concentration, polymer concentration, hydrogen pressure, and temperature, a detailed study of the hydrogenation of cis‐1,4‐polyisoprene catalyzed by the Ru complex, Ru(CHCH(Ph))Cl(CO)(PCy3)2 was carried out by monitoring the amount of hydrogen consumed. Infrared and 1H‐NMR spectroscopic measurements confirmed the final degree of hydrogenation. The hydrogenation of cis‐1,4‐polyisoprene followed pseudo‐first‐order kinetics in double‐bond concentration up to high conversions of double bond, under all sets of conditions studied. The kinetic results suggested a first‐order behavior with respect to total catalyst concentration as well as with respect to hydrogen pressure. The apparent activation energy for the hydrogenation process, obtained from an Arrhenius plot, was 51.1 kJ mol−1 over the temperature range of 130 to 180°C. Mechanistic aspects of the catalytic process are discussed. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3259–3273, 2004
Synthesis and characteristics of polyelectrolyte complexes composed of chitosan and hyaluronic acid
Authors: Kim Seon Jeong , Shin Su Ryon , Lee Kyu Back , Park Yong Doo , Kim Sun I. 
Published: January 2004

AbstractPolyelectrolyte complexes (PEC) composed of various weight ratios of chitosan and hyaluronic acid (HA) were prepared. The PECs were formed by a reaction of the oppositely charged polymers. The characterizations of the PEC films were investigated by using Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The PECs were found to swell rapidly, reaching equilibrium within 30 min, and exhibited relatively high swelling ratios of 250–325% at room temperature. The swelling ratio increased when the pH of the buffer was below pH 6, as a result of the dissociation of the ionic bonds, and with increments of temperature. Therefore, the swelling ratios of the films were pH and temperature dependent. DSC was used to determine the amount of free water in the PEC films, which increased with increasing chitosan content. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2908–2913, 2004
Radiation crosslinking and sorption properties of hydrogels based on 1‐vinyl‐2‐pyrrolidone, hydroxyethyl methacrylate, and their copolymers
Authors: Nizam El‐Din Horia M. M. , Maziad Nabila A. , El‐Naggar Abdel Wahab M. 
Published: January 2004

AbstractThis work has been concerned with the synthesis of the hydrogels of poly (vinyl pyrrolidone) (NVP), poly (hydroxy ethylmethacrylate) (HEMA), and their copolymer under the effect of gamma radiation in the presence of N,N‐methylenebisacryl‐amide (MBAm) as a crosslinking agent. The effect of the different factors that may affect the gelation and yield product, such as solvent composition and irradiation dose, was investigated. The formed hydrogels were characterized in terms of swelling in water and different organic solvents, X‐ray diffraction (XRD), and IR spectroscopic analysis. The sorption capability of these hydrogels towards some commercial basic and acid dyesstuffs was also studied. The results showed that a solvent mixture composed of equal contents of water and methanol is the most suitable to afford the minimum sol fraction and the highest yield product at a minimal irradiation dose of 10 kGy. It was observed that NVP hydrogel displayed the highest swelling in water, alcohols, and dimethyformamide of ∼1300% and a lower tendency to swell in nonpolar solvents. The results showed that HEMA hydrogel has a high affinity to absorb basic dyes while NVP has a tendency for acid dyes. Also, the sorption of either the basic or acid dyes by the different hydrogels was found to greatly depend on the concentration of dye in solution and the mass of the used hydrogel. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3274–3280, 2004
Microwave‐assisted and conventional polycondensation reaction of optically active N,N′‐(4,4′‐sulphonediphthaloyl)‐bis‐L‐leucine diacid chloride with aromatic diamines
Authors: Mallakpour Shadpour , Kowsari Elaheh 
Published: January 2004

Abstract3,3′,4,4′‐Diphenylsulfonetetracarboxylic dianhydride (1) was reacted with L‐leucine (2) in acetic acid and the resulting imide‐acid (3) was obtained in high yield. The diacid chloride (4) was prepared from diacid derivative (3) by reaction with thionyl chloride. The polycondensation reaction of diacid chloride (4) with several aromatic diamines such as 4,4′‐sulfonyldianiline (5a), 4,4′‐diaminodiphenyl methane (5b), 4,4′‐diaminodiphenylether (5c), p‐phenylenediamine (5d), m‐phenylenediamine (5e), 2,4‐diaminotoluene (5f), and 1,5‐diaminonaphthalene (5g) was developed by using a domestic microwave oven in the presence of a small amount of a polar organic medium such as o‐cresol. The polymerization reactions were also performed under two conventional methods: low temperature solution polycondensation in the presence of trimethylsilyl chloride, and a short period reflux conditions. A series of optically active poly(amide‐imide)s with inherent viscosity of 0.25–0.42 dL/g were obtained with high yield. All of the above polymers were fully characterized by IR, elemental analyses, and specific rotation techniques. Some structural characterizations and physical properties of these optically active poly (amide‐imide) s are reported. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2992–3000, 2004
Swelling characterization of the semiinterpenetrating polymer network hydrogels composed of chitosan and poly(diallyldimethylammonium chloride)
Authors: Kim Seon Jeong , Yoon Seoung Gil , Kim In Young , Kim Sun I. 
Published: January 2004

AbstractTemperature‐ and pH‐responsive semiinterpenetrating polymer network (SIPN) hydrogels, constructed with chitosan (CS) and poly(diallyldimethylammonium chloride) (PDADMAC), were studied. The characterizations of the IPN hydrogels were investigated by fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and swelling tests, under various conditions. CS/PDADMAC SIPN hydrogels exhibited a relatively high swelling ratio, in the range of 248–462%, at 25°C. The swelling ratio of CS/PDADMAC IPN hydrogels are pH, temperature, and ionic concentration dependent. DSC was used for the quantitative determination of the amounts of freezing and nonfreezing water. The amount of free water increased with increasing PDADMAC content in the IPN hydrogels. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2876–2880, 2004
Segmented MDI/HMDI‐based polyurethanes with lowered flammability
Authors: Pielichowski Krzysztof , Słotwińska Dominika , Dziwiński Euzebiusz 
Published: January 2004

AbstractA series of segmented polyurethanes (PUs) based on 4,4′‐diphenylmethane diisocyanate and 1,6‐hexamethylenediisocyanate; polyoxypropylenediol (POPD); and low‐molecular chain extenders, 1,2‐propanediol or 3‐chloro‐1,2‐propanediol was obtained by solution polymerization and characterized by GPC and microscopic methods. Spherical aggregates with diameter of about 200 nm, arranged in a quasi‐linear mode, were observed by SEM technique; further investigations by the TEM method revealed hard‐segment domains of longitudinal shape, with length of about 5–10 nm, showing some features of the arrangement along a “director” axis. The process of thermal decomposition was monitored by thermogravimetric analysis in both dynamic and isothermal mode; to gain a deeper look into the mechanism of decomposition, kinetic analysis was performed. First, isoconversional methods showed a multistep decomposition route, as the value of (apparent) energy of activation changes from about 150 kJ/mol in the first step up to about 350 kJ/mol in the third step, which corresponds to the energy of dissociation of CC bonds and leads to a char (carbonaceous) residue. Further calculations by means of the linear regression method revealed that kinetic model functions describing the degradation process of PU that does not contain chlorine were Bna → An → Fn, whereby for chlorine‐containing polyurethanes the CnB → An → An model was applied as best fit. Volatile products were investigated by pyrolysis–gas chromatography/mass spectrometry method at 770°C; the low molecular weight decomposition products, which were identified, indicate that the depolymerization process, yielding mainly diols and isocyanates through breakage of urethane bonds, prevailed during the thermal treatment under pyrolytic conditions. Finally, the mechanism of thermal degradation of modified polyurethanes with lowered flammability was proposed. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3214–3224, 2004
Strain–tensor components, crystallite shape, and their effects on crystalline structure in silk I
Authors: Sangappa  , Okuyama Kenji , Somashekar R. 
Published: January 2004

AbstractBy using the X‐ray powder data obtained from Bombyx mori silk fibroin in silk I modification, we have estimated the strains by using profiles of several (hkl) reflections observed in the fibroin. For this purpose, we have used line profile simulation and matching with the experimental, on the basis of a paracrystalline one‐dimensional Hosemann's model proposed earlier. The shape of the crystallite and size along different directions in the fibroin have also been estimated and presented here. From these results, the strain tensor has been computed by using the approach given by Wilke and Martis. The effect of these strains on the molecular arrangement within the crystal structure and the nature of changes in the chain within the unit cell which participates in inducing the intrinsic strain during the formation of the fiber (silkII) are reported here. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3045–3053, 2004
Application of concentrated emulsion polymerization for preparation of ion‐exchange chromatography columns
Authors: Baharvand H. , Rabiee A. 
Published: January 2004

AbstractConcentrated inverse emulsion polymerization was used for making chromatography columns [based on crosslinked polystyrene divinylbenzene (PS–DVB)] with pore sizes less than 10 μm. For application of these columns in ion‐exchange chromatography, the sulfonation process was performed by concentrated sulfuric acid. According to X‐ray fluorescence analysis and ASTM D2187‐94 standard test method, the total capacity of resins (sulfonated PS–DVB) increased with increasing time. To obtain high‐capacity resins, the sulfonation process was carried out over two steps. The optimum sulfonation time for the first and second sulfonation steps was 24 and 48 h, respectively. By increasing the DVB content, the capacity of resins passed through a maximum; thus the optimum amount of DVB, as crosslinking agent in the sulfonation process, was 22.5%. The structure of columns was analyzed by scanning electron microscopy (SEM). SEM evaluations showed that the porous structure of PS–DVB resin was maintained intact after the sulfonation steps. According to DSC–thermal gravimetry thermograms, it was confirmed that the residual monomer concentration after polymerization process was negligible. Also, the PS–DVB resins exhibit thermal stability up to 300°C and this quantity would increase with increasing amount of DVB weight percentage. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2973–2979, 2004
Infiltration of uncured elastomers into silica agglomerates
Authors: Astruc Marianne , Collin Véronique , Rusch Steven , Navard Patrick , Peuvrel‐Disdier Edith 
Published: January 2004

AbstractThe degree of impregnation of an agglomerate by the suspending matrix is an important parameter because it influences the agglomerate cohesion and thus has a direct effect on dispersion mechanisms. Penetration kinetics reported in the literature were only measured in Newtonian or not very elastic matrices, although one of the main applications is the dispersion of porous filler in elastomers. The aim of this article is to study the infiltration of porous silica agglomerates by uncured elastomers using optical microscopy. The application of the model of Bohin (infiltration of a Newtonian fluid into a porous sphere) is discussed. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3292–3300, 2004
Laser light‐scattering molecular weight analysis of a poly(fluoro acrylate)
Authors: Meyer Andrew , Jones Nick , Lyle Scott , Venkataramani Shiv , Clark John , Kranbuehl David 
Published: January 2004

AbstractTwo leading macromolecular characterization techniques were employed for analysis of a unique, difficult to dissolve fluorinated polymer system (PFA), Poly(N‐methyl perfluoroocytyl sulfonamido ethyl acrylate). Multiangle Laser Light Scattering (MALLS) and Viscosity–Right Angle Laser Light Scattering (RALLS) were used to measure the weight‐average molecular weight and molecular size‐radius using the solvent HFIP, 1,1,1,3,3,3‐hexafluoroisopropanol. HFIP is shown to be an excellent solvent for light scattering measurements on the PFA as well as on Polyamide‐11 and Polymethyl methacrylate. It is shown that the Viscosity‐RALLS approach gives results that differ from the MALLS system due to the assumptions used. It is also shown that the addition of salt does affect the molecular weight dependence of the radius of gyration but not the value of Mw. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3447–3454, 2004
The role of ordered block copolymer morphology in the performance of organic/inorganic photovoltaic devices
Authors: Gratt Jason A. , Cohen Robert E. 
Published: January 2004

AbstractA triblock copolymer consisting of hole‐transport, electron‐transport, and nanocluster‐binding moieties was used in the fabrication of photovoltaic test devices. Depending on the casting solvent used in the device fabrication process, the morphology of the block copolymer in the devices was either an ordered, perpendicular cylindrical phase or a uniformly mixed homogeneous material. The photovoltaic action spectra of these two device types revealed clearly that the charge collection efficiency was influenced favorably by the microphase separation of the ordered system. Underlying mechanisms for these observations are discussed. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3362–3368, 2004