bluuebunny/crossref_metadata_2025_split huggingface dataset:
TPX/siloxane blend membrane for oxygen enrichment
Authors: Lai J. Y. , Wu G. J. , Shyu S. S. 
Published: April 2003

AbstractThe effects of composition, molecular weight, and milling temperature on homogeneity, gas permeability, selectivity of oxygen/nitrogen, and mechanical strength of the TPX/siloxane blend membranes were studied. By adjusting the blending conditions and hence controlling the homogeneity, the gas permeability of TPX membrane was significantly improved without loss of oxygen/nitrogen selectivity. The oxygen permeability of 1.57 × 10−8 cm3 (STP) cm/cm2 s cm Hg and the oxygen/nitrogen permeation ratio of 6.92 can be obtained under the condition of TPX (MX‐001)/siloxane (75,000 MW) = 9/1 at 65°C milling temperature. This membrane possesses 133 kg/cm2 tensile strength and 92% elongation. The morphology of the blend membranes was studied.
Transport of alkali metal ions against its concentration gradient through 2,3‐epithiopropyl methacrylate–methacrylic acid copolymer membrane
Authors: Nonaka Takamasa , Maeda Hirotoshi , Nakayama Morio , Egawa Hiroaki 
Published: April 2003

AbstractCationic exchange membranes were prepared with 2,3‐epithiopropyl methacrylate (ETMA)–methacrylic acid (MAc) copolymer. Transport of Li+ against its concentration gradient through the membranes was investigated by using the system containing HCl and LiCl (left side) and LiOH (right side). The rate of transport of Li+ increased with increasing MAc content in the membranes with less than 56.3 mol % MAc. The rate of transport and transport fraction of Li+ could be increased by using the copolymer membranes irradiated with ultraviolet light, because the physical and chemical structure of the membrane made of ETMA–MAc copolymer can be easily changed by irradiation with ultraviolet light. The transport in this system, where one side of the membrane in a cell was acidic and the other alkaline, was influenced significantly by the initial H+ concentration on the acidic side.
Characterization and free radical polymerization of liquid crystalline acrylic acid/cellulose diacetate and N‐vinyl‐2‐pyrrolidinone/cellulose diacetate solutions
Authors: Kozakiewicz Joseph J. , Magniess Jane E. 
Published: April 2003

AbstractPolymerizations of liquid crystalline solutions of cellulose diacetate (CDA) in acrylic acid (AA) and N‐vinyl‐2‐pyrrolidinone (NVP) were conducted in an attempt to prepare molecular composites (polymer blends) processing a rigid rod polymer with liquid crystalline orientation. CDA was found to form liquid crystalline solutions in both AA and NVP at concentrations avove 40 wt% CDA. Polymerization of anisotropic 50 wt% CDA‐AA and CDA‐NVP solutions occurred with considerable retention of the starting solution anisotropy and yielded homogeneous blends (1 Tg) when the rate of polymerization was fast relative to the phase separation of the free radically polymerizing AA or NVP with CDA. Slow polymerizations lead to phase separated blends (2 Tg).
Kraft lignin in polyurethanes I. Mechanical properties of polyurethanes from a kraft lignin–polyether triol–polymeric MDI system
Authors: Yoshida H. , Mörck R. , Kringstad K. P. , Hatakeyama H. 
Published: April 2003

AbstractPolyurethanes with various NCO/OH ratios and kraft lignin contents were synthesized by polymerization of kraft lignin (free of the low and high molecular weight fractions), a propylene–oxide‐based polyether triol and polymeric MDI in tetrahydrofuran solution. Films were made by solvent casting and tested with respect to swelling behavior and tensile properties. The main findings were: At low NCO/OH ratios, kraft lignin contributed effectively to the formation of the three dimensional network; under particular conditions of NCO/OH ratio and kraft lignin content, polyurethanes of considerable toughness were obtained; at high kraft lignin contents, the obtained polyurethanes were hard and brittle regardless of the NCO/OH ratio used.
Derivative infrared spectroscopy of cotton cellulose
Authors: Pandey S. N. 
Published: April 2003

AbstractA new technique of derivative infrared spectroscopy for the study of polymer structure with special reference to cotton cellulose is described. Absorption spectra of cotton cellulose are compared with second deravative spectra. In case of absorption spectra, while determining the wavelength and intensity of a given absorption, in many cases, difficulties arise due to the presence of an interfering band which, as a consequence of overlap, prevents the determination of the above properties. Derivative spectroscopy provides valuable information on structural properties of cellulose. It yields spectra gradient, which facilitates the separation of overlapping absorption bands to resolve and detect absorptions; neither were unresolvable as a consequence either of multiple bands overlap or of low intensity. Hence, the measured wavelength in the second derivative spectra are more precise than the absorption spectra. For fine structural studies of cellulose, derivative spectra may provide more useful information as the absorption bands are more clearly defined.
The dynamics of the continuous emulsion polymerization of methylmethacrylate
Authors: Schork F. J. , Ray W. H. 
Published: April 2003

AbstractExperimental data on the dynamics of the continuous emulsion polymerization of methylmethacrylate are presented. Techniques for on‐line reaction monitoring and digital data acquisition as reported previously are used to generate dynamic data on the monomer conversion and free emulsifier concentration. Data are reported confirming the existence of multiple steady states and limit cycles in the CSTR (continuous stirred tank reactor) emulsion polymerization of methylmethacrylate. Data are also reported suggesting the presence of steady states in the absence of micelles in the reactor. The possible causes of these phenomena, and the conditions under which they occur are discussed.
Thermal conductivity of a polymer composite filled with mixtures of particles
Authors: Agari Y. , Tanaka M. , Nagai S. , Uno T. 
Published: April 2003

AbstractA new thermal conduction model is proposed for a polymer system filled with a mixture of several types of particles. Predicted values by the new model are compared with experimental data. The model is derived by extending a model that was previously proposed for a two‐phase system. The following equation is derived from the new model: log λ = V · (X2 · C2 · log λ2 + X3 · C3 · log λ3 + (1 − V) log (C1 · λ1. When the thermal conductivities of polymer and particles (λ1, λ2, λ3, …) and a mixing ratio of particles (X2, X3, …) are known, thermal conductivity of the filled polymer (λ) with several types of particles can be estimated from the equation, with any volume content of particles (V). Furthermore, from each polymer–filler composite (two‐phase system) data, the thermal conductivity of a composite filled with different filler particles can be estimated.
Phosphorescence and fluorescence of poly(vinyl alcohol) films
Authors: Mieloszyk January , Drabent Regina , Siódmiak Józef 
Published: April 2003

AbstractLuminescence properties of poly(vinyl alcohol) (PVA) films were investigated at room and low (103 K) temperatures. It was estimated that the PVA films can be regarded as luminescentless matrices when excited by radiation of wavelengths greater than 420 nm (λexc≥ 420 nm).
New epoxy‐imide resins cured with bis(hydroxyphthalimide)s
Authors: Ichino Toshihiro , Hasuda Yoshonori 
Published: April 2003

AbstractNew epoxy‐imide resins were synthesized using bis(hydroxyphthalimide)s (BHPIs). Among these resins, that cured with BHPI(DDS), synthesized from 4,4′‐diaminodiphenylsulfone, exhibits the best thermal resistance, reaching a tan δ maximum temperature of 230°C. This resin also features a tensile lap shear adhesive strength of 320 kgf/cm2 when applied to steel test pieces. The cure reaction was followed by infrared spectroscopy and dynamic mechanical analysis. The ring‐opening reaction between the phenolic hydroxyl group of BHPI and the epoxy group is observed, and accelerated by a tertiary amine catalyst, triethylamine.
Flame retardation of polypropylene: Effect of organoantimony compounds on the structural and mechanical properties
Authors: Bajaj P. , Jha N. K. , Maurya P. L. , Misra A. C. 
Published: April 2003

AbstractStructural properties of polypropylene (PP) filled with flame‐retardant (FR) organoantimony compounds, viz., triphenylstibinedibromide and triphenylantimony (V) derivatives of tribromotrichloro‐, and pentachlorophenols at 5–20 phr additive loading, were investigated through differential thermal analysis (DTA), and X‐ray diffraction (XRD) studies. Incorporation of flame retardant in PP has decreased the melting temperature (Tm) and heat of fusion (ΔHf) of PP. Crystallization peak and the onset temperature, crystallization rate and crystallite size are also influenced by the addition of these compounds. The percent crystallinity obtained by XRD is in good agreement with that obtained by DTA. The tensile properties of the flame‐retardant‐filled PP are also studied, and an attempt has been made to correlate the tensile properties with that of structural changes in polypropylene. Fracture mechanism of flame‐retardant‐filled PP has been investigated with the help of a scanning electron microscope.
Diffusion of miscible polymers in multilayer films
Authors: Keskkula H. , Paul D. R. , Young P. , Stein R. S. 
Published: April 2003

AbstractThermal and optical properties of multilayer films of miscible polyethyloxazoline (PEOx) and poly(styrene‐co‐acrylonitrile) have been studied as a function of time and temperature. Differential scanning calorimetry showed that the distinct, characteristic Tg's of the component polymers of the original films disappear after only short heating periods above Tg, and a single transition appears. The new transition region is broad at first, but narrows on subsequent heating. The measurement of light transmittance as a function of wavelength through the heat‐treated films also confirms the diffusion of the miscible polymers and gives results which are comparable to the thermal measurements. Films from immiscible polymers of polystyrene and PEOx retain their properties after various heat treatments. A qualitative discussion of the diffusion process as examined by the thermal measurements is presented.
Polycarbonate‐polyurethane semi‐interpenetrating polymer networks: Tg behavior and morphology
Authors: Shyu S. S. , Chen D. S. , Lai J. Y. 
Published: April 2003

AbstractThe dynamic mechanical properties, transition behavior, and morphology of polycarbonate (PC)‐polyurethane (PU) semi‐interpenetrating polymer networks (semi‐IPNs) and linear blends were studied by means of Rheovibron, differential scanning calorimetry (DSC), and transmission electron microscopy (TEM). Two glass transition temperatures corresponding to polycarbonate and polyurethane were observed and microphase separation was further evident with TEM. In PC/PU semi‐IPNs, two glass transition temperatures were shifted inwardly indicating that the interpenetrating network of polyurethane increases the mutual miscibility of PC and PU. The average phase domain was 500Å in semi‐IPNs and the phase domains were in the range 1000–6000 Å in linear blends of the corresponding polymers. The compatibilities of PC and PU were greatly influenced by the molecular weight of polyols in PU prepolymer and the ratio of NCO/OH; lower molecular weight polyols and higher NCO/OH ratio resulted in better compatibility, and finer phase domains in PC and PU linear blends and semi‐IPNs.
Effects of trans‐polyoctenylene on the mechanical properties of NBR
Authors: Björk Folke , Stenberg Bengt 
Published: April 2003

AbstractTrans‐polyoctenylene (TOR), a high‐polymer polymerization product of cyclooctene, has found use as a processing aid in high‐viscosity rubber stocks. We have compared some physical and mechanical properties of a NBR‐compound with TOR with those of the same compound without TOR. Mooney viscosity was lower for the compound with TOR. Cylinders with a height and diameter of 20 mm were molded. It was found that stress–relaxation measured in the common static way was almost the same for the two compounds. Dynamic stress–relaxation occurred much more rapidly for the compound with TOR. The compound with TOR increased in hardness more rapidly when aged in air, and showed a higher swelling in oil. The DSC results imply that TOR is incorporated as a separate phase in the parent rubber. The sealing properties are affected detrimentally when TOR is used as a processing aid in NBR.
The graphical evaluation of ionic dye sorption isotherms using dimensionless groups
Authors: McGregor Ralph , Tamura Keiko , Iijima Toshiro 
Published: April 2003

AbstractA graphical method is proposed for the analysis of experimental data on the equilibrium sorption of ions by charged polymers. The method uses dimensionless groups of variables, which are based on a generalized Donnan theory. Graphical comparisons of theoretical curves with experimental data‐point sets permit rapid estimation of theoretical parameters. The use of dimensionless groups clarifies the complex interactions between the individual sorption variables. This simple procedure consists of relative lateral and vertical displacements of the data point graphs and the theoretical graphs along their coordinate axes. The graphical comparisons help to reveal the nature of departures from the basic theoretical model. Examples of the method are given for oxycellulose/methylene blue and polyacrylonitrile polymer/cationic dye systems.
Anisotropic reinforcement in elastomers containing magnetic filler particles
Authors: Sohoni G. B. , Mark J. E. 
Published: April 2003

AbstractMagnetic particles of iron oxide were blended into portions of a high molecular weight sample of poly(dimethylsiloxane) which were then peroxide cured in a magnetic field. Strips cut from the resulting elastomers parallel and perpendicular to the magnetic lines of force were studied with respect to their equilibrium swelling and their stress–strain isotherms in elongation. Both resistance to swelling (as measured by the volume fraction of polymer in the network) and the elongation modulus increased with increase in the amount of filler. They were also generaly larger in the direction parallel to the field, and the differences increased both with increase in the amount of filler and with increase in the strength of the magnetic field. Stress relaxation also increased with amount of filler and field strength, thus illustrating the importance of adsorption of the polymer onto the filler particles, and its subsequent desorption under stress.
Copolymerization of vinyl chloride with 1‐olefins. Part IV. Investigation of rheological and mechanical properties of copolymers
Authors: Mrázek Zdeněk , Kolínský Miloslav , Horáček Ivan , Černoch Jan 
Published: April 2003

AbstractCopolymers of vinyl chloride with propene, 1‐butene, and 1‐pentene having the same content of 1‐olefin (4.0 ± 0.5 mol%) and various molar mass and copolymers with a comparable molar mass and the same composition were prepared. By measuring rheological and mechanical properties of this assembly of samples, which also included the reference vinyl chloride homopolymer, it was possible to estimate the effect of molar mass and of the individual comonomers. The copolymers under investigation possessed improved processing properties and did not suffer any deterioration of important mechanical properties.
Structure and properties of p‐carboxysuccinanilic polyester resins
Authors: Nosseir Michael H. , Doss Ninette L. , Taufik Sohair Y. 
Published: April 2003

AbstractPolyester resins were prepared by the reaction of p‐carboxysuccinanilic acid ethyl ester with ethylene glycol and 1,4‐butenediol. Also, unsaturated polyester resins were prepared by the copolymerization of p‐carboxysuccinanilic acid ethyl ester and maleic anhydride with ethylene glycol, 1,6‐hexanediol, 1,4‐butenediol, and 2‐butyne‐1,4‐diol. All the polyester resins and the copolyesters have been characterized and were found to cure with styrene, except those prepared in the absence of maleic anhydride. The properties of the cured products in the form of films were determined. Infrared and nuclear magnetic resonance (NMR) spectroscopy were used for both qualitative and quantitative analyses of the polyester resins and their hydrolyzate products after curing with styrene.
Polyurethane‐based sealants modified by blending with Kraft lignin
Authors: Feldman D. , Lacasse M. , St. J. Manley R. 
Published: April 2003

AbstractAn investigation was conducted to establish the viability of blending Kraft lignin (L), a naturally occuring, readily available polymer resource, with polyurethane‐(PU) based sealants. The sealants were tested in a detailed program where lignin‐sealant blends, having blend ratios varying between 0 and 20 pbw L, were prepared on substrates of aluminum, mortar, and wood, and subjected to laboratory control (C), artificial weathering (AW), and natural weathering (NW) conditions. Results of tension testing showed that generally, lignin acts as a reinforcing agent which adds rigidity to the polymeric matrix, as indicated by the increase in toughness and modulus of blended sealants with the addition of lignin. In addition, the curing mode of PU, as determined by sequence hardness testing, was modified with the addition of lignin.
Packing density of the amine‐crosslinked stoichiometric epoxy networks
Authors: Bellenger V. , Dhaoui W. , Morel E. , Verdu J. 
Published: April 2003

AbstractThe packing densities (Van der Waals volume/molar volume) were determined at 293 K for various epoxide–amine stoichiometric networks. They are noticeably higher than those of linear polymers except strongly hydrogen bonded ones [polyamides, poly(vinyl alcohol)]. By extrapolation of the dilatometric data, it was found that the packing densities at the frontiers of the glassy state (0 K and Tg) of the epoxy networks are comparable to those of linear polymers having the same theoretical hydrogen bond density (polyamides). However, for a given packing density at 0 K, the packing density at Tg is higher for a network than for the corresponding linear polymer.
Preparation of quinazolone–imide copolymers and their thermal and chemical etching properties
Authors: Kubota Shigeru , Ando Torahiko 
Published: April 2003

AbstractQuinazolone‐imide copolymers were prepared by polycondensation of 6,6′‐methylenebis(2‐methyl‐3,1‐benzoxazine‐4‐one) and 3,3′,4,4′‐benzophenonetetracarboxlic dianhydride and 4,4′‐oxydianiline. Their thermal properties by TGA and their chemical etching properties by the use of the etchant composed of hydrazine hydrate and ethylenediamine were studied. The copolymers obtained had good solubility and excellent heat resistance and gave flexible and tough films. The chemical etching properties were more subject to influence of the polymer composition than the thermal properties were.
Polyester polyols for polyurethanes from pet waste: Kinetics of polycondensation
Authors: Vaidya U. R. , Nadkarni V. M. 
Published: April 2003

AbstractThe kinetics of polyesterification of the glycolyzed PET waste with adipic acid is reported. Glycolysis of PET waste was carried out with ethylene glycol at three different ratios of PET waste to glycol. The glycolyzed products could be readily polyesterified by reacting with adipic acid, to give polyester polyols with low acid number. Kinetics of polyesterification of the glycolyzed product made from 62.5% ethylene glycol (EG) and 37.5% waste were investigated further at different hydroxyl to carboxyl ratios. Reaction conditions were nonisothermal, comparable to the industrial process scheme consisting of two isothermal regions at 170° and 200°C. The kinetic results of the polyesterification of glycolyzed PET waste are compared to the polyesterification of pure diols, namely ethylene glycol and bis(hydroxyethyl) terephthalate (BHET) with adipic acid. The reactions follow second‐order kinetics at 170°C and the rate of polyesterification of the mixed diol system from PET waste lies intermediate between those of the pure diols, namely, EG and BHET. Ethylene glycol exhibited the highest reactivity. At 200°C the kinetic plots of the mixed diols from PET waste were nonlinear, and thus the reaction may not follow second‐order kinetics. The nonlinearity is explained in terms of the different reactivities of the different diol species in the reaction mixture. The polyester polyols, when cured with polymeric 4,4′ diphenyl methane diisocyanates, gave polyurethane rigid foams and elastomers.
13C‐NMR characterization of poly(1,5‐hexadiene)
Authors: Cheng H. N. , Khasat N. P. 
Published: April 2003

AbstractPoly(1,5‐hexadiene) was prepared and its structure characterized by high‐field 13C nuclear magnetic resonance. The polymer was shown to contain repeating five‐membered rings separated by methylene bridges, with both cis and trans placements present in a 54 : 46 ratio. The result is compatible with the Marvel‐Garrison two‐step reaction mechanism.
Processing–structure–property relationships in poly(ethylene terephthalate) blown film
Authors: Ma Tung Chan , Han Chang Dae 
Published: April 2003

AbstractAn investigation was undertaken to establish processing–structure–property relationships in poly(ethylene terephthalate) (PET) blown film. For the study, a commercial grade of PET was used to fabricate the film specimens by means of a tubular film blowing process. In this process, the stretch temperature was accurately controlled by an oven. The annealing treatment of the oriented specimens involved clamping the sample in an aluminum frame and then putting the clamped sample in an oven, controlled at a temperature between the glass transition temperature (70°C) and the melting point (255°C) of PET, for a specified annealing period. The structure of the blown film samples was characterized by density, bulk birefringence, flat plate wide‐angle X‐ray scattering, and pole figure analysis. The processing variables, namely, takeup ratio, blowup ratio, and stretch temperature were found to significantly affect the bulk birefringence and density of the oriented PET blown film samples. It was found that both the bulk birefringence and density of the specimens increased upon annealing at an elevated temperature. Both the crystalline and amorphous orientation functions were calculated from the data of bulk birefringence, density, and the pole figure analysis. Compared to the amorphous orientation functions, the crystalline orientation functions were found to be relatively insensitive to the processing variables. It was concluded that equibiaxially oriented PET films can be produced via a tubular film blowing process by judiciously controlling the processing and annealing conditions. It has also been observed that the tensile stress‐at‐break of equibiaxially oriented PET film increases with decreasing stretch temperature and increasing annealing temperature.
Low‐density polyethylene depth profile analysis by photoacoustic spectroscopy
Authors: De Oliveira Marcelo Ganzarolli , Pessoa Osvaldo , Vargas Helion , Galembeck Fernando 
Published: April 2003

AbstractNear‐infrared photoacoustic spectra of polyethylene (1 mm slab) were taken in the modulation range 10–240 Hz, which corresponds to thermal diffusion layers in the 56−11 μm range. Thick‐layer spectra are very similar to polyethylene film transmission spectra, but large differences are observed between the spectra taken at various modulation frequencies. From 10 to 80 Hz, all the spectral band intensities decrease linearly with ω−a where ω is the light modulation frequency and a varies from 0.48 to 1.00 for different constituent groups. The analysis of spectral intensity as a function of modulation frequency shows that peak intensity ratios of CH3, CH2, and OH groups, relative to that of methylene groups, increase as thinner, closer‐to‐surface polymer layers are sampled. From this we conclude that near‐to‐surface layers of solid polyethylene are richer in CH3, CH2 and OH groups than the polymer bulk.