bluuebunny/crossref_metadata_2025_split huggingface dataset:
Orientation development in retensilized, biaxially oriented polypropylene films
Authors: Strobel Joan M. , Nam Sehyun 
Published: April 2003

AbstractA basic study of orientation development in retensilized, biaxially oriented polypropylene films was performed. Wide‐angle X‐ray scattering (WAXS) and birefringence measurement techniques were used to examine films prepared under specific processing conditions. Biaxial orientation factors were determined for these films and were correlated with end‐use properties of the materials. In particular, the dispensability of oriented polypropylene films was found to correlate with crystalline‐phase and amorphous‐phase orientation factors. Dispensability is a relatively important property of pressure‐sensitive tapes; it is defined as the force necessary to cut a film backing over a serrated blade of the type used in commercially available adhesive‐tape dispensers.
Hydrosilylation crosslinking of silicone rubber catalyzed by bis (1,5‐cyclooctadiene) di‐μ,μ′‐chlorodirhodium
Authors: Heidingsfeldová Marta , Schätz Miroslav , Czakoová Marie , C̆apka Martin 
Published: April 2003

AbstractHydrosilylation vulcanization of addition silicone rubber catalyzed by bis (1,5‐cyclooctadiene) di‐μ,μ′‐chlorodirhodium at 150° was studied. The course of vulcanization, rubber network density, and mechanical properties of the vulcanizate are discussed with respect to the structure and molecular weight of the reactive groups of telechelic and internal vinylmethylpolysiloxanes and crosslinking methyl (hydrogen) dimethyl siloxane copolymers. Molecular weights of the polysiloxane components as well as the ration of unsaturated and Si—H groups were optimized. The results are in agreement with the theory of rubber elasticity of polymer networks and show wide application possibilities of the catalyst used.
Ionomers made from terpolymers with uniform poly(methyl methacrylate) grafts
Authors: Xie Hong‐Quan , Zhou Shi‐Biao 
Published: April 2003

AbstractTerpolymers with uniform poly(methyl methacrylate) (PMMA) grafts were prepared by terpolymerization of PMMA macromonomer, butyl acrylate, and acrylic acid in benzene using AIBN as initiator. During terpolymerization the macromonomer polymerizes faster than the monomers at the beginning but slower at the latter stage. The terpolymers were purified by solvent extraction and fractional precipitation. The average grafting number per chain of the terpolymers was determined to be 3–8. Ionomers were obtained by neutralization of the terpolymers with alkali hydroxide or metallic acetate. Dynamic mechanical spectrum of the ionomer shows the existence of two Tg's, which implies the occurence of microphase separation. The ionomer exhibits high damping over a temperature range from −25 to 100°C. Both PMMA grafts and metallic carboxylate content raise the tensile strength of the ionomer and lower the ultimate elongation. The tensile strength of ionomers neutralized with different metallic ions decreases in the following order: Pb2+ > Zn2+ > Na+ > Ca2+ > Mg2+ > K+. The ionomers with uniform PMMA grafts show much better mechanical properties than the terpolymer without neutralization or the ionomer without PMMA grafts.
Structure and ESR investigation of plasma‐polymerized film of hexafluoropropene
Authors: Wang Daike , Chen Jie 
Published: April 2003

AbstractThe structure and constitution of plasma‐polymerized film of C3F6 (PPHFP) have been investigated by measuring its ESCA, 19F‐NMR, and IR spectra. It is found that the PPHFP film was a high degree of branching and 57% of quaternary carbons are linked to CF3 groups. It is also found that the constitution of PPHFP film is changed greatly at high power and a large amount of Si and O atoms are linked to the PPHFP chains. Furthermore, using element analysis, ESCA, and theoretical calculation by electronegative model, we found that the nitrogen atoms get into the PPHFP chains when using N2 as plasma gas. Besides, the radical concentration in the film is obtained to be 9.97 × 1019 spins/g and its half‐life is about half a year at room temperature in Ar gas. Having investigated decay process of the radicals in two gases of air and Ar, we calculated the activation energies and rate constants of radical recombination and oxidation reactions at different temperatures.
Polypeptide spheres. VII. Macroreticulation of spherical poly(γ‐methyl‐L‐glutamate) beads
Authors: Ihara Hirotaka , Furusawa Hideki , Li Xin , Hirayama Chuichi 
Published: April 2003

AbstractSpherical beads from poly(γ‐methyl‐L‐glutamatate) alone were prepared using various diluents for macroreticulating by the “suspension and evaporation” method. The porosity and the pore size of the beads obtained were remarkably dependent on the chemical structure of a diluent. This is related to the specific miscibility of a diluent with poly(γ‐methyl‐L‐glutamate). For example, decahydronaphthalene made the beads much more macroporous than tetrahydronaphthalene with similar hydrophobisity: the aromaticity of diluent increases the miscibility. However, it was found that long‐chain alkyl compounds with a miscible group such as methyl dodecanoate, oleic acid, linoleic acid, and dialkyl‐phthalate were not only very effective for macroreticulating, but also induced narrow pore‐size distribution. In addition, the diluent influenced physicochemical properties of the beads to cause specific affinity to proteins.
Permeation of dissolved carbon dioxide in synthetic membranes
Authors: Nakagawa Tsutomu , Naruse Atsuko , Hicuchl Akon 
Published: April 2003

AbstractPermeability coefficients of dissolved carbon dioxide in poly(dimethyl siloxane), plasmatreated poly(dimethyl siloxane) membranes, and other membranes were measured by applying a carbon dioxide electrode in a liquid to liquid diffusion cell. The apparent permeability coefficients of carbon dioxide polystyrene, low density polyethylene, and nylon membranes in a liquid phase were observed to be higher than those in a gas phase due to a plasticizing effect of water molecules in the membranes. Boundary layer's resistance was estimated for plasma‐treated and nontreated poly(dimethyl siloxane) membranes. The plasma treatment (10 W for 1 min in this study) which makes hydrophilic surfaces without change of bulk polymer properties was found to be effective to decrease the boundary layer's thickness and to increase the apparent permeability coefficient in the liquid phase.
Mechanistic study on photocuring of a methacrylates copolymer by benzophenones
Authors: Ito Yoshikatsu , Aoki Yasushi , Matsuura Teruo , Kawatsuki Nobuhiro , Uetsuki Masao 
Published: April 2003

AbstractThe types of photochemical reactions that will occur in the photosensitive resin for optical devices, poly(methyl methacrylate‐co‐crotyl methacrylate) (PMMA–CMA) doped with meta‐benzoylbenzophenone (BBP), were investigated. Oxetane formation, hydrogen abstraction followed by radical coupling, and pinacol formation were found to occur. The quantum yield for disappearance of benzophenone (BP) in the PMMA–CMA film was estimated as 0.68. The pendant crotyl group seems to be a major photoreaction site.
Effect of thermal pretreatment on the fracture behavior of polycarbonate in medium strain rate tensile tests
Authors: Pääkkönen E. J. 
Published: April 2003

AbstractThe fracture properties of as‐received and annealed (48 h at 403 K) commericial polycarbonates (PC) were examined in tensile tests with an average strain rate of ė = 2 s−1. Both materials were subjected to tensile tests at temperatures ranging from 223 to 423 K. The results were processed by a computer interfaced to the testing machine. The tensile strength of the annealed (pretreated) PC was superior to that of the as‐received (untreated) material. The elongation at break and the fracture energy, then, decreased due to annealing at all temperatures, yet followed impact strength curves. Fracture analysis and fracture morphology revealed clear differences in the behavior of the materials. Fracture nucleation occurred commonly at several points in the pretreated specimens, whereas only one nucleation point was found in the untreated specimens. Shear yielding morphology, which indicated plastic deformation, started to appear at a lower temperature in the pretreated specimens than in the untreated ones.
Poly(ethylene terephthalate)/polyarylate blends: Influence of interchange reactions on the melting behavior of poly(ethylene terephthalate)
Authors: Eguiazábal J. I. , Cortázar M. , Iruin J. J. 
Published: April 2003

AbstractThe influence of the interchange reactions of poly(ethylene terephthalate) (PET)/polyarylate (PAr) blends on the melting behavior of isothermally crystallized PET has been studied. PET shows three melting endotherms in the pure state and also when mixed with PAr. These endotherms are explained in terms of primary and secondary crystallization processes as well as recrystallization during the calorimetric scan. It is also shown that interchange reactions hinder the crystallization processes of PET.
Oxygen‐plasma‐treated polypropylene interfaces with air, water, and epoxy resins: Part I. Air and water
Authors: Occhiello E. , Morra M. , Morini G. , Garbassi F. , Humphrey P. 
Published: April 2003

AbstractOxygen plasma treatment of polypropylene (PP) surfaces led to introduction of oxygencontaining functionalities, with consequent improvement of surface wettability. A combination of X‐ray photoelectron spectroscopy (XPS), static secondary ion mass spectroscopy (SSIMS), and contact angle measurements (water‐in‐air and air‐in‐water) allowed us to characterize the behavior of the treated surface in contact with air (low‐energy surface) and water (high‐energy surface).The treated surface showed the tendency to rearrange itself to minimize its interfacial energy. When contacted with air (low‐energy surface), polar groups were buried away from the polymer/air interface, while in contact with water (high‐energy surface) polar groups remained at the polymer/water interface.When contacted with air, the polymer surface layer rearranged by macromolecular motions within itself, since interdiffusion with the bulk polymer seems forbidden. These motions are thermally activated and it was possible to obtain an apparent activation energy (58.1 kJ/mol) close to those reported for other vinyl polymers.
Effect of organic amine type on the structure and properties of the complex Zn(II) salts of ethylene–methacrylic acid copolymer with organic amines
Authors: Hirasawa Eisaku , Hamazaki Hirohide , Tadano Kenji , Yano Shinichi 
Published: April 2003

AbstractThe complex Zn(II) salts of ethylene–methacrylic acid copolymer (EMAA) were synthesized by using various organic amines from monoamines to polyamines, from primary amines to tertiary amines, and from molecular amines to polymer amines. Thermal analyses by differential scanning calorimetry (DSC), and the measurement of stiffness, melt flow rate (MFR), and dielectric properties were employed for the complex salts. It was found that the valence, strength of base, rigidity and flexibility, and bulkiness of the organic amines affect the degree of crystalline order of the ionic crystallites, which governs the stiffness of the complex ion ionomers. The stiffness is higher for the complex salts which form the higher orderliness in the ionic aggregates. The organic amines with two or more primary aliphatic amino groups and higher boiling temperatures from more rigid ionic crystallites in the complex ion ionomers leading to the enhanced modulus. Monoamines or polyamines with amino groups attached to flexible chains such as polyether and polysiloxane scarcely develop ionic crystallites and preferentially solvate the amorphous region including ionic groups leading to the decreased modulus. These results provide us with the fundamental information to control the modulus of ionomers.
Characterization of acetylene terminated sulfone (ATS) resin. II. Thermal analysis of the resin
Authors: Stevenson W. T. K. , Goldfarb I. J. , Soloski E. J. , Houtz M. J. 
Published: April 2003

AbstractThe kinetics and thermodynamics of the cure and post‐cure reactions of an acetylene terminated sulfone (ATS) resin mixture and pure fractions from that mixture were studied using differential scanning calorimetry. Thermal stabilities were measured by programmed thermogravimetry under helium, and oxidative stabilities using isothermal thermogravimetry in air. Microstructural changes accompanying the cure reaction were identified using infrared spectroscopy. Early products of thermal degradation were trapped for identification and quantitative analysis using the technique of sub‐ambient thermal volatilization analysis. We found that glass transition temperatures increase with crosslink density in the resin, that oxygen is able to copolymerize or couple with the polyenes to produce peroxides or hydroperoxides (respectively) which subsequently decompose to form terminal alcohols on the polyene, that weight loss in air at 600°F is an oxidative process that is insensitive to resin crosslink density, and that sulfone functionality constitutes the thermal weak link in the ATS resin system.
Epoxy resins based on aromatic glycidylamines. III. Kinetics of intramolecular cyclization of N,N‐bis(2‐hydroxy‐3‐chloropropyl)aniline
Authors: Podzimek Š. , Dobáš I. , Švestka Š. , Eichler J. , Kubín M. 
Published: April 2003

AbstractThe course of intramolecular cyclization of N,N‐bis (2‐hydroxy‐3‐chloropropyl) aniline (DCHA) was followed by HPLC. The rate constants (at 70, 85, 100, and 115°C) and the Arrhenius parameters for individual reaction steps were determined. The resulting product was isolated by semipreparative HPLC and its structure was confirmed by NMR spectroscopy. Attention was also paid to the different reactivity of DCHA diastereoisomers.
Metal ion removal by dyed cellulosic materials
Authors: Shukla S. R. , Sakhardande V. D. 
Published: April 2003

AbstractFurther studies on adsorption of different metal ions by the four dyed and undyed cellulosic substrates namely cotton fibers, bleached bamboo pulp, jute fibers, and sawdust were carried out. Different metal ions adsorbed were Fe2+, Fe3+, Pb2+, and Hg2+. The equilibrium metal adsorption was studied by EDTA method. The control and dyed substrates adsorbed these metal ions to a significant extent, thus providing an effective and cheap method for adsorption of costly but polluting and toxic metals like Pb2+ and Hg2+. The adsorption levels varied up to 95% for various substrate–dye–metal ion combinations.
Viscometric investigation of the poly(acrylic acid)–polyacrylamide interpolymer association
Authors: Staikos G. , Tsitsilianis C. 
Published: April 2003

AbstractA viscometric approach to the formation of interpolymer complexes between a polyelectrolyte, polyacrylic acid, and a non‐ionic polymer, polyacrylamide, is investigated. The following method compares the reduced viscosity of the polymer mixture with an “ideal” value which results from the additivity of the reduced viscosities of the two components taking into account the polyelectrolyte effect of polyacrylic acid. This reveals the formation of a compact complex or gel‐like interpolymer association which depends on the polymer mixture composition. Both the influence of the degree of polyacrylic acid neutralization and of the presence of a salt on the interpolymer association are also studied.
Synthesis, characterization, and evaluation of poly[n‐alkyl(oxy)‐n‐hexyl acrylates]
Authors: Pratap G. , Shantha K. L. , Rao D. V. Mohan , Rao V. S. Bhaskar 
Published: April 2003

AbstractOxoalkyl acrylates of long‐chain 7‐oxo alcohols were synthesized as intermediate monomers for the preparation of poly[n‐alkyl (oxy) ‐n‐hexyl acrylates] for the first time. These polymers have wide applications as fluidity improvers (pour point depressants) for petroleum crude oils. Characterization of all the intermediate monomers was done by IR, 1H‐NMR, and MS, and that of polymers by IR, 1H‐NMR, and GPC. These polymers were systematically investigated for their efficacy as pour point depressants on three types of high waxy Bombay High (Indian) crudes. In addition to establishing the pour points, relevant rheological parameters of the untreated and the additive‐treated crude oils were determined in the laboratory with a rotational viscometer. Results of the crude oils that were pre‐ and posttreated with these new polymers have shown enhanced activity of flow properties as compared to the crudes that were treated with poly(n‐alkyl acrylate) flow improver.
A simplified degradation model for nylon 6,6 polymerization
Authors: Steppan D. D. , Doherty M. F. , Malone M. F. 
Published: April 2003

AbstractA simplified reaction scheme for nylon 6,6 degradation that is consistent with all the published data is described. The degradation model has been incorporated into a flowing film polymerizer model with a distribution of residence times in order to predict molecular weight, amount of undegraded (amine and carboxyl) and degraded chain ends, and the extent of crosslinking. The outlet average molecular weight and water concentration come to steady state in about one mean residence time after a change in polymerizer operating conditions, whereas the degradation products continue to change slowly even after four residence times. Also, it is possible to choose the operating conditions of the polymerizer so the same molecular weight is produced at two different temperatures but with very different amounts of degradation products giving rise to products of significantly different quality.
Structural changes during polystyrene orientation: A study of optical birefringence and wide angle X‐ray scattering
Authors: Vancso G. , Snétivy D. , Tomka I. 
Published: April 2003

AbstractResults of coupled optical birefringence and wide‐angle X‐ray scattering (WAXS) measurements on uniaxially oriented, atactic, glassy polystyrene (PS) samples are reported. Orientations were achieved in tensile test experiments performed slightly above the glass transition temperature. The elongated samples were quenched after orientation. The applied force was kept constant during cooling. The second order moments of the chain orientation distribution function (ODF) were calculated from the azimuthal profile of the scattered X‐ray intensity from measurements made on five PS samples with different degrees of orientation. For ODF calculations the first, equatorial halo was used. The influence of the second, meridional halo was removed by resolving the WAXS patterns into three peaks. The intrinsic azimuthal linewidth of the WAXS profile was estimated and taken into account in the ODF calculations. The magnitude of the intrinsic birefringence Δnint was determined using the linear relationship between the birefringence and the second order moment of the ODF. A value for Δnint of −0.05 was obtained. This result was used to calculate the angle between the normal plane of the benzene ring and the chain axis. A comparison with previously published results indicates that the average relative orientation of the benzene ring with respect to the chain axis was changing in our samples during stretching. This structural difference is attributed to strong deformation of the network and retarded relaxation during sample preparation.
Preparation of Rh‐containing cellulose acetate films and the chemistry of Rh in cellulose acetate
Authors: Park Kwang‐Min , Shim Il‐Wun 
Published: April 2003

AbstractRhCl [P(C6H5)3]3 complexes have been incorporated in cellulose acetate as a dispersion medium using cosolvent (tetrahydrofuran). The interactions between Rh (I) complexes and cellulose acetate (CA) are examined by infrared spectroscopy and thermal analysis. The chemical reactivities of Rh–CA films have been investigated by reacting Rh sites with CO, H2, O2, and C2H4 in the temperature range 90–150°C and at a pressure of less than 1 atm. Three different Rh‐carbonyls and a Rh‐hydride species formed in CA are characterized by their infrared spectra. Treatment of 10 or 20 wt % Rh–CA films with hydrogen (600 torr) at 150°C produces small Rh metal particles of ca. 10 Å or less in diameter in CA, which show catalytic activities under mild conditions in various reactions such as hydrogenation of C2H4, oxidation of CO, and Fischer–Tropsch type reactions.
Emulsion polymerization of methyl methacrylate using poly(methyl methacrylate‐co‐2‐hydroxypropyl methacrylate)‐graft‐polyoxyethylene as the stabilizer
Authors: Jialanella Gary L. , Piirma Irja 
Published: April 2003

AbstractThis study involved the use of an amphipathic graft copolymer, poly(methyl methacrylate‐co‐2‐hydroxypropyl methacrylate)–graft–polyoxyethylene, as a stabilizer in the emulsion polymerization of methyl methacrylate. The stabilizing effectiveness of this graft copolymer was studied as a function of its chemical structure. It was found that the stabilizing effectiveness of the graft copolymer was independent of the molecular weight of the backbone within the investigated range of 4 × 103 g/mol to 2 × 104 g/mol. In all cases, stable emulsion polymerizations of methyl methacrylate were observed. Effective stabilization also occurred when the graft moieties possessed a molecular weight of either 2 × 103 g/mol or 5 × 103 g/mol. However, the stabilizing effectiveness was found to be dependent on the amount of polyoxyethylene (POE) contained in the graft copolymer. In this case, graft copolymers possessing 67% by weight POE were poor stabilizers, but ones with 85% POE were very good stabilizers. Moreover, the graft copolymers were found to be superior stabilizers as compared to POE homopolymers.
The dynamic mechanical analysis of epoxy–copper powder composites using azole compounds as coupling agents
Authors: Ding Jianfu , Chen Chinmin , Xue Gi 
Published: April 2003

AbstractThe dynamic mechanical properties of cured epoxy resin have been studied in which copper powder treated or untreated with azole compounds was used as fillers. The untreated fillers do not shift the glass transition temperature of the matrix polymer of the composites, whereas the storage modulus rises with increasing content of fillers. The application of azole compounds as coupling agents, which could react with both copper and epoxy resin, extended the polymer–filler interactions. The composite filled with copper powder treated with benzotriazole shows a strong reinforcement effect and high resistance to moisture.
Synthesis and properties of cationic resins derived from aniline‐modified epoxy resins and various amines
Authors: Yang Chin‐Ping , Lee Lung‐Ta , Yu Wen‐Tsong 
Published: April 2003

AbstractAniline‐modified epoxy resin which contains tertiary amine in the middle of the polymer chain was synthesized by the reaction of aniline and epoxy resin. The resulting aniline‐modified epoxy resin and two commercial epoxy resins with different epoxy equivalent weights were reacted with 2‐ethylhexanol‐blocked toluene diisocyanate (2‐EH‐blocked TDI) to obtain thermally crosslinkable epoxy resins. These epoxy resins were subsequently reacted with various secondary amines and partially neutralized with acetic acid to give thermally crosslinkable cationic resins. The resulting cationic resins were dissolved in suitable solvents and mixed with deionized water to form emulsions. The crosslinking properties, emulsion, and electrodeposition properties of these resins were studied in some detail. The electro‐deposition yields of the emulsions prepared from aniline‐modified epoxy resins were higher than those of other emulsions. The crosslinked films prepared from aniline‐modified epoxy resins were also glossier than those prepared from commercial epoxy resins. High deposition yield and high glossiness were the characteristic properties of the aniline‐modified epoxy resins. Thermal properties were not affected by aniline‐modified epoxy resins.