bluuebunny/crossref_metadata_2025_split huggingface dataset:
N‐phenylglycine‐(thio)xanthene dye photoinitiating system and application to photopolymer for visible laser exposure
Authors: Yamaoka Tsuguo , Zhang Yu‐Chuan , Koseki Ken'ichi 
Published: April 2003

AbstractIt was found that the bimolecular type photoinitiators consisting of N‐phenylglycine and (thio)xanthene dyes exhibited high initiating efficiency on irradiation of visible light. From the time‐resolved spectroscopic study, the free radical is formed by the sensitized decarboxylation of N‐phenylglycine in the presence of (thio)xanthene dye. By using these initiating systems, the visible laser sensitive photopolymer was prepared and the imaging characteristics were evaluated.
Adsorption of chitosan and a quaternized derivative on kaolin
Authors: Domard A. , Rinaudo M. , Terrassin C. 
Published: April 2003

AbstractAdsorption of Chitosan on kaolin was tested and a comparison was made with a fully quaternized derivative. The influence of pH, molecular weight, and acetyl content on the results was also studied. The adsorption isotherms and the flocculating properties as functions of the various parameters are discussed.
Sulfonic acid group‐containing thin films prepared by plasma polymerization
Authors: Inagaki N. , Tasaka S. , Miyazaki H. 
Published: April 2003

AbstractPlasam polymerization of hydrocarbon/sulfure dioxide mixtures, C2H/SO2, C2H4/SO2, and CH4/SO2 mixtures, was investigated to obtain thin films containing sulfonic acid groups. Plasma polymerization of C2H2/SO2 and C2H2/SO2 mixtures gave filmlike products but that of the CH4/SO2 mixtures did not. The plasma polymers possessed much amount of sulfur and oxygen moieties with hydrocarbon chains. The sulfur moieties involved thio, sulfite, and sulfonic acid groups. This groups was a main product and reached 70–80 mol % of the total sulfur moieties. The remains (20–30 mol %) were sulfonic acid and sulfite groups. The oxygen moieties were hydroxyl and carbonyl groups with small amount of carbonxyl groups. The plasma polymers showed and hydrophilicity (the surface energy was 54–56mN/m) and good antithrombogenity.
Compounding of cellulose fibers with polypropylene: Effect of fiber treatment on dispersion in the polymer matirx
Authors: Raj R. G. , Kokta B. V. , Dembele F. , Sanschagrain B. 
Published: April 2003

AbstractThe compounding of Kraft pulp with polypropylene was stuided using a laboratory higheshear roller blender. Dipsersion was characterized by measuring the size and number of agglomerates in a thin compression‐moldled sheet. The effects of parameters such as surface treatment and mixing conditions were investigated. It is shown that with a suitable treatment, better dispersion of fibers can be achieved.
Influence of different imidazole catalysts on epoxy‐anhydride copolymerization and on their network properties
Authors: Bouillon Nelly , Pascault Jean‐Pierre , Tighzert Lan 
Published: April 2003

AbstractThe copolymerization of naidc and methyltetrahydrophthalic anhydrides and diglycidyl ether of bisphenol A (DGEBA) with various stoichiometric ratios [r = 2[anhydride]/DGEBA] and with different concentrations of several imidazoles has been studied. These results are compared with those obtained with a tertiary amine such as benzyldimethylamine, a well‐known efficient catalyst of epoxy‐anhydride copolymerization. Thermal and hydrothermal behaviors of these networks also have been examined.
Swelling of anionic and cationic starch‐based superabsorbents in water and saline solution
Authors: Castel D. , Ricard A. , Audebert R. 
Published: April 2003

AbstractStarch graft superabsorbents were prepared by graft copolymerization either with polyacrylonitrile (PAN) and saponification of the resulting copolymer or with trimethyl–aminoethylacrylate chloride (CMA) and methylene bisacrylamide as crosslinking agent. The influence of several structural parameters on the swelling properties of these absorbents have been studied: crosslink density, ionic content, and composition of the starch. As expected, the absorbency decreases with an increase of the crosslink density. It increases with the ionic content of the graft copolymer up to a maximum, an excess of charges leading to a swelling decrease. The PAN branch length depends on the origin of the starch. High molar weight PAN was grafted onto waxy corn, a starch with high amylopectin content. The swelling increases with increasing molar weight of PAN up to 5 × 105. In saline solution the absorbency of both ionic gels decreases significantly. However, in the presence of multivalent ions their behavior is different. For cationic absorbents the swelling depends on the ionic strength but not on the ion valency. On the other hand, anionic absorbents are significantly affected by multivalent cations.
The effect of processing parameters on the morphology of an immiscible binary blend
Authors: Favis B. D. 
Published: April 2003

AbstractIn this study an immiscible blend of polypropylene(PP) and polycarbonate (PC) was examined. Experiments were carried out in an internal mixer and the objective was to examine the influence of the time of mixing, the speed of rotation of the rotors as well as the effect of time under quiescent conditions on the size and size distribution of the minor phase. The morphology was studied by light and electron microscopy and the photographs were quantitatively analyzed by semiautomatic image analysis. The effect of the time of mixing was studied for up to 20 min at three viscosity ratios for PC dispersed in PP. The most significant particle size deformation and disintegration processes take place within the first 2 min of mixing. After 2 min very little reduction in the size of the minor phase is observed up to 20 min mixing time, although some phase size/time dependence was observed at an intermediate viscosity ratio. The influence of rotor speed was also studied and the results indicate that this blend is insensitive to changes in the speed of rotation of the rotor over a three‐ to fourfold range. The effect of time at 250°C under quiescent conditions was studied at 7% and 23% composition (volume fraction) for PP dispersed in PC and also for PC in PP. Coalescence coarsening was observed only for 23% PC in PP where the particle size was found to increase by 75% after approximately 90 min at temperature.
Cellulose stability and delignification after alkaline hydrogen peroxide treatment of straw
Authors: Martel P. , Gould J. Michael 
Published: April 2003

AbstractNeutron diffraction profiles for cellulose from different sources were compared before and after alkaline hydrogen peroxide (AHP) treatment. It was found that AHP treatment did not cause detectable changes in the structure of highly polymerized cellulose. In measurements on wheat straw, peaks were observed at the angles characteristic of pure cellulose. Changes, with AHP treatment, of the intensities, positions, and widths of these peaks were consistent with effects due to delignification, which frees the cellulose lattice from strains caused by the binding of lignin.
Rheological and morphological properties of thermal‐aged poly(phenylene sulfide) resin
Authors: Ma Chen‐Chi M. , Hsiue Lin‐Tee , Wu Wen‐Guey , Liu Wen‐Liang 
Published: April 2003

AbstractThis paper discusses the morphological properties of thermal‐aged poly(phenylene sulfide) (PPS) resin by Fourier‐transform infrared spectroscopy (FT‐IR) and solid‐state 13C‐NMR. Also included is a method of applying the dynamic melt viscoelastic properties to determine the molecular weight distribution of the PPS resin. For virgin PPS resin, two resonance peaks were detected by NMR magic angle spinning (MAS) and cross polarization (CP) studies. However, four additional peaks can be seen for heat‐treated PPS resin, indicating that the aromatic ring in PPS resin was attacked by sulfur‐containing species or by the aryl ether group. The two most important reactions are crosslinking and chain extension. However, the chain extension is predominant when PPS is heated in nitrogen. The results coincide with the phenomenon observed in FT‐IR studies. The molecular weight distribution of thermal‐aged PPS resin was determined from dynamic melt viscoelasticity data. Results show that the longer the preheated time the broader the molecular weight distribution. It indicates that crosslinking and chain‐extension reaction may have occurred when PPS resin was heated in air.
Axial compressive strength of carbon fiber
Authors: Ohsawa Tadashi , Miwa Minoru , Kawade Masato , Tsushima Eiki 
Published: April 2003

AbstractEfforts were made to estimate the axial compressive strengths of carbon fibers from the fiber fragment lengths produced by subjecting to a strain greater than the fiber ultimate strain for PAN‐based and pitch‐based carbon fibers. The estimated compressive strength of carbon fibers decreases with increasing temperature in a temperature range from room temperature to 100°C. This decrease in compressive strength may be accounted for by a decrease in the radial compressing force. The real compressive strength, determined by extrapolating a linear relationship between the estimated compressive strength and the radial compressing force, is approximately 25–60% of tensile strength for PAN‐based fibers, while it is approximately 10–35% for pitch‐based fibers.
Solid phase graft copolymerization. I. Effect of initiator and catalyst
Authors: Rengarajan Ramesh , Vicic Michael , Lee Sunggyu 
Published: April 2003

AbstractPolypropylene–maleic anhydride (PP–MA) graft copolymers were produced from isotactic homopolymer polypropylene (molecular weight > 150,000) utilizing the technique of solid phase graft copolymerization. A high degree of graft (about 8–10%) was achieved on 150 mesh (U.S. Standard Sieve) samples using this process. This free‐radical‐initiated, catalyst‐aided grafting process was effective at low temperatures (100–120°C), atmospheric pressure, and low residence times (60 min). The powder was mixed in a low shear, fixed speed, continuous mixer where the ingredients were added in stages to effect the reaction. The interfacial agent was used to etch the polymer to provide sites for the reaction. The powder was removed from the reactor on completion of the reaction. This process can be further applied to graft other reactive monomers on polypropylene (PP).
Aspects of the surface and bulk nitration of cellulose in nitric acid, nitric acid/water, and nitric acid/dichloromethane mixes
Authors: Short R. D. , Munro H. S. 
Published: April 2003

AbstractElectron spectroscopy for chemical analysis (ESCA) has been employed to follow the surface nitration of cellulose papers in nitric acid–water and nitric acid–dichloromethane mixes with the aim of: elucidating the identity of the nitrating species in these mixes and from comparison of surface and bulk degree of substitution (DOS) further understanding on the role that morphology plays in the nitration of cellulose in these mixes. In nitric acid, nitric acid–water and nitric acid–dichloromethane mixes, surface nitration was observed to be slow (cf. to that reported in mixed acids) and the concentration of nitronium ion was observed to be low (cf. to mixed acids). On the basis of these observations and from the results of kinetic experiments, reported herein, it is proposed that the nitronium ion, NO2+, is the important nitrating species of cellulose in these nitric acid mixes. Nitration in all but the most concentrated nitric acid–dichloromethane mixes produced equal surface and bulk DOS; however, nitration in pure nitric acid produced different surface and bulk DOS. The latter result implies that the heterogeneous nature of the nitration reaction can influence the DOS achieved.
Synthesis and characterization of mannich bases from cardbisphenol
Authors: Ramasri M. , Rao G. S. Srinivasa , Sampathkumaran P. S. , Shirsalkar M. M. 
Published: April 2003

AbstractWater‐soluble Mannich bases were synthesized from cardbisphenol by Mannich reaction and were characterized by1H‐NMR and13C‐NMR spectroscopic methods. The effect of electrodeposition parameters on the film formation from binders and from the pigmented composition were studied. The polymers gave uniform coatings with good mechanical properties and the pigmented systems exhibited high resistance to organic solvents and excellent corrosion resistance properties.
Solute and penetrant diffusion in swellable polymers: X. Swelling of multiethylene glycol dimethacrylate copolymers
Authors: Walker Curt M. , Peppas Nikolaos A. 
Published: April 2003

AbstractThe swelling behavior of copolymers containing 2‐hydroxyethyl methacrylate and various multiethylene glycol dimethacrylates was examined at 25°C. These highly crosslinked copolymers show some hydrophilic behavior due to the hydroxyl groups of HEMA. Analysis of the swelling data indicates and anomalous water transport in the network, which depends on the degree of crosslinking attained according to the dimethacrylate comonomer molar fraction in the copolymerization feed. Thermomechanical analysis data were used to further characterize the network structure.
Deformation of polyelectrolyte gels under the influence of electric field
Authors: Shiga Tohru , Kurauchi Toshio 
Published: April 2003

AbstractDeformation of acrylic acid–acrylamide copolymer gels in an aqueous solution under the influence of a dc electric field was studied. In the electric field, the gel swells, shrinks, or bends. It depends on the concentration of polyion coo− in the gel. When the concentration is low, the gel shrinks, and, when high, it swells. The gel which does not contain polyion is not influenced by the electric field. The long and thin gel is bent in an arc. The bent gel can be recovered to the original shape by removing the applied electric field or by changing the polarity of the applied electric field. The deformation is closely related to two substantial changes. One is the change of the osmotic pressure caused by the ion concentration difference between the inside and the outside of a gel. The other is the conformational change of the polymer network with decreasing of the polyion concentration.
Properties of epoxy resins cured with ring‐alkylated m‐phenylene diamine blends
Authors: Storey Robson F. , Dantiki Sudhakar , Adams J. Patrick 
Published: April 2003

AbstractDiglycidyl ether of bisphenol‐A was cured, individually, with diaminoisopropyl benzene (DAIPB), diaminoethyl benzene (DAEB), blends of DAIPB/DAEB (up to 40 wt % DAEB), and DAIPB modified with up to 5 wt % amine‐terminated poly(butadiene‐co‐acrylonitrile) liquid rubber (ATBN). For each diamine system glass transition temperature (differential scanning calorimetry) and room temperature tensile properties (Instron) were determined. Blends of DAIPB/DAEB produced cured resins displaying greatly increased tensile strength (up to 50% higher) and slightly lower glass transition temperature compared with resins cured with either diamine alone. DAIPB modified with ATBN yielded moderately improved tensile properties over DAIPB alone. Blends of DAIPB/DAEB (from 10 to 40 wt % DAEB) were observed to be eutectic liquids at room temperature.
Studies on the physical properties of polyethylene‐g‐acrylic acid to immobilizing glucose oxidase
Authors: Hsiue Ging‐Ho , Wang Chee‐Chan 
Published: April 2003

AbstractA new type of polymer support for immobilizing glucose oxidase was investigated. The starting copolymer was acrvlic‐acid‐grafted polyethylene (PE‐g‐AA). The copolymer was prepared with gamma ray irradiation induced grafting under controlled conditions utilizing post‐irradiation procedures. A number of factors were examined. They were: (1) the effect of the hydrophilic/hydrophobic nature of the support on the enzyme membrane activity; (2) the Michaelis constant (km); (3) the thermal stability, the rate constant for the thermal denaturation, and the activation energies for the denaturation of immobilized and soluble enzyme; and (4) the physical properties of the support affecting the immobilized enzyme activity. An attempt was made to immobilize the enzymeutilizing carbodiimide (CMC) as the coupling agent. This immobilization method resolves in a high enzyme activity. The hydrophilicity of the support and the activity of the enzyme membrane were proportional to the degree of grafting. When the temperature was higher than 60°C, the immobilized glucose oxidase was less sensitive to thermal inactivation than the native enzyme. Various polyethylene was studied; the LLDPE was preferred. The type of polyethylene, the thickness, kind of grafting monomers, and the degree of grafting would influence the activity of the enzyme membrane.
Measuring the modulus of a sphere by squeezing between parallel plates
Authors: Rodriguez Ferdinand , Patel Suman K. , Cohen Claude 
Published: April 2003

AbstractFormulas are derived relating the deformation resulting from the application of a force f to the poles of a sphere of uniform modulus. When the force f is applied, the poles, originally a distance 2R* apart, now are a distance 2Ru apart. Also, the diameter of the sphere at its equator is increased from 2R* to a new value 2Re. For an ideal rubbery material with a shear modulus of g, the force is related to the change in equatorial diameter by

Thus, measurement of the increase in relative radius at the equator as a function of force applied at the poles yields the modulus directly. The change in Rv also can be related to G, but a numerical integration is required. Equations can also be derived relating modulus to dimensional changes when Hooke's law is used in place of ideal rubber elasticity.
Glow discharge polymerization of reactive functional silanes on poly(methyl methacrylate)
Authors: Laoharojanaphand P. , Lin T. J. , Stoffer J. O. 
Published: April 2003

AbstractGlow discharge polymerization among such reactive functional silances as 3‐methacryloxypropyltrimethoxysilane (MSL), 3‐glycidoxypropyltrimethoxysilane (ESL), and vinyltrimethoxysilane (VSL) on poly(methyl methacrylate) was investigated by means of Fourier transform infrared spectroscopy, ESCA analysis, and contact angle measurement. Flow rate of monomer influenced both polymer deposition rate and polymer elemental composition. Infrared spectra showed differences in chemical structure among the polymers prepared from the different silanes. All of the polymers obtained contained similar chemical groups such as CH3, CH2, SiOSi, and SiOC. Polymers deposited from MSL and ESL contained highly hydrophilic functional groups like COH, SiOH, and CO on the uppermost layer while that from VSL contained highly hydrophobic functional groups like CH3 groups. Chemical analysis by ESCA and contact angle measurement gave evidence for the similarity of the polymers prepared from MSL and ESL, in contrast with the differences of the polymers prepared from VSL.
Pervaporation separation of water/ethanol mixtures through polysaccharide membranes. IV. The relationships between the permselectivity of alginic acid membrane and its solid state structure
Authors: Mochizuki Akira , Amiya Shigetoshi , Sato Yoshio , Ogawara Hisashi , Yamashita Shuzo 
Published: April 2003

AbstractMembranes composed of alginic acid, which is one of the anionic polysaccharides, were investigated as pervaporation membranes for the separation of water/alcohol mixtures. The selectivity of the alginic acid membrane increased markedly by more than 10,000 when the carboxyl group of alginic acid was neutralized by bases. The counter cation (Li+, Na+, K+, Rb+, and Cs+) influenced the permeation rate for the alginate membranes, which varied from 0.1 kg/m2h for the Li version to 1.0 kg/m2h for the Cs version, but the counterion had hardly any effect on the selectivity. The behavior could not be explained simply by the affinity of the alginate membranes toward water, but could be explained well by the conformation change and mobility of alginate molecules investigated by CP/MAS 13C‐NMR, water mobility within the alginate membrane, and crystallinity of the membrane.
Mechanism of flame‐retardant action of tris (2,3‐dichloropropyl) phosphate on epoxy resin
Authors: Jianzong Li , Shiyuan Chen , Xiaoming Xu 
Published: April 2003

AbstractThe use of tris (2,3‐dichloropropyl) phosphate (TCPP) as a flame retardant in epoxy resin cured by methltetraphydrophthalic anhydride was studied. Although TCPP is an organophosphorus flame retardant containing chlorine, the date obtained from LOI measurements showed that TCPP was not more effective compared to other flame retardants containing only phosphorus. In order to understand the mechanism of flame retardant action of TCPP on epoxy resin, the effect of TCPP on the thermal degradation of the resin was investigated using thermogravimetry, differential scanning calorimetry, infrared spectroscopy, and elemental analysis. TCPP was shown to act predominantly by condensed phase mechanism, to catalyze decomposition, and to enhance char formation. A mode of flame retardant action of TCPP on epoxy resin by phosphorus in condensed‐phase was proposed.
The dependence of kinetic density curves of suspension PVC powder on the content of defective particles
Authors: S̆evčík Stanislav , Mrázek Zdeněk 
Published: April 2003

AbstractThe method of kinetic density curves was used to investigate the sieve fractions of suspension PVC powder of the type Neralit S‐682 with various content of difficult to process particles (“fish eyes”). It was found that by increasing the contenet of fish eyes, the effective density curves are shifted to lower density values. This finding can be utilized in the charaterization and evaluation of sieve fraction of PVC.
Studies on impact modification of polystyrene (PS) by ethylene–propylene–diene (EPDM) rubber and its graft copolymers. I. PS/EPDM and PS/EPDM‐g‐styrene blends
Authors: Shaw S. , Singh R. P. 
Published: April 2003

AbstractEthylene–propylene–diene (EPDM) rubber is an excellent rubber for outdoor use. High impact polystyrene (PS) containing EPDM rubber may show improved weathering resistance. PS is incompatible with EPDM; hence bulk polymerization technique is adopted for the synthesis of graft products which show limited compatibility with PS. Two initiators were chosen at two different working temperatures to produce high grafting efficiency and grafting percentage. In the present system, it is shown that the graft copolymer and polystyrene compositions show higher improved impact strength behavior than that of the products based upon simple dispersion of EPDM in polystyrene.
Effect of catalyst on the molecular weight advancement of poly(ethylene ether carbonate) polyols
Authors: Harris Robert F. 
Published: April 2003

AbstractSodium stannate is a parferred catalyst for the preparation of poly(ethylene ether carbonate) polyols. It can be removed from the polyol by treatment with acetone to precipitate most of the catalyst followed by adsorption of the soluble catalyst on Florisil and filtration. Sodium metaborate and potassium carbonate catalysts are not precipitated to any extent by acetone but can be reduced to lower levels by adsorption on Florisil and filtaration. The molecular weight of the poly(ethylene ether carbonate) polyol and the water content of the system have a strong influence on the effectiveness of this purification technique. Catalysts are more easily removed from higher molecular weight polyols with low water content. The effect of sodium stannate catalysts level on the molecular weight advancement of poly(ethylene ether carbonate) polyols has been studied. The rate of advancement to a 3000 molecular weight product is increased with good CO2 retention (95%) when the tin level is 100–500 ppm. At higher catalyst levels, product decomposition to 1,4‐dioxane becomes increasingly important. Complete mass balances and distillate analyses are presented to show the effects of catalyst levels. The product composition is dominated by the CO2 content of the reactant and the advancement conditions.