bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of chelation on the selective transport of alkaline‐earth metal ions in asymmetric cellulose acetate hyperfiltration membranes
Authors: Lee K. L. , Hopfenberg H. B. , Stannett V. T. 
Published: April 2003

AbstractThe rejection of calcium and/or magnesium ion by asymmetric cellulose acetate hyperfiltration membranes is increased significantly by formation of the corresponding alkaline‐earth metal chelate. Typically solute fluxes are reduced by a factor of 5 consequent to chelation with ethylenediaminetetraacetic acid (EDTA) at pH 6.0. Selective chelation and, in turn, selective transport of magnesium is observed when equimolar solute mixtures corresponding to 1:1:1 magnesium:calcium:EDTA are hyperfiltered. Under these conditions, calcium successfully competes for the stoichiometrically limiting EDTA, and the rejection of magnesium is lower than the rejection observed for the hyperfiltration of the MgEDTA2− complex in the absence of competitive calcium. Alternatively, the rejection of the CaEDTA2− complex is increased under these identical conditions, presumably as a consequence of specific interactions between the available free magnesium and the cellulose acetate membrane. The effects reported here all seem to be related to reductions in solute diffusivity associated with the increased size of the alkaline‐earth metal ion complex.
Grafting of cyclic carbonates onto cotton and modified cottons
Authors: Ward Truman L. , Benerito Ruth R. 
Published: April 2003

AbstractCyclic carbonates react with amines to form carbamates, with alcohols to form hydroxyalkylated products, and with dibasic acids or dibasic acids plus a glycol to form polyesters. These types of reactions between ethylene, propylene, or glycerine carbonate and cotton, either unmodified or modified to contain amine or carboxyl groups, were investigated. Effects of method of application, temperature, time of reaction, and pressure were studied. Temperature in excess of 100°C and reduced pressures were satisfactory for removing the water formed. Reaction between cyclic carbonates, dibasic acids, a glycol, and nonaqueously prepared carboxymethylated cotton in a vacuum oven yielded a fabric with conditioned and wet wrinkle recovery of approximately 300(W + F)°. Infrared spectra, wrinkle recovery, and weight gain indicated that crosslinks formed in reactions between unmodified or carboxymethylated cotton and the cyclic carbonate. Reactions with aminized or diethylaminoethylated cotton formed terminal grafts.
Effect of low temperatures on polymorphic structures of cotton cellulose
Authors: Jung Hilda Z. , Benerito Ruth R. , Berni Ralph J. , Mitcham Donald 
Published: April 2003

AbstractEffects of low temperatures upon fine structures of cotton pretreated with either liquid ammonia or caustic of mercerizing strength were investigated. Temperatures of cotton after impregnation with liquid ammonia were lowered by (1) liquid nitrogen, (2) acetone–Dry Ice, (3) acetone, or (4) simple evaporation. With alkali‐impregnated fabrics, temperature was lowered by immersion in liquid nitrogen. Changes in fine structure of ammonia‐ and alkali‐celluloses were evaluated by x‐ray diffraction before and after removal of each swelling reagent. After treatment with either ammonia or caustic soda, extent of crystalline modification was increased as temperature was reduced. X‐ray diffractograms taken while liquid ammonia was still present indicated that the cellulose I structure of cotton sheeting was converted to cellulose III at liquid nitrogen temperatures; extent of conversion was approximately that obtained when a looser yarn structure was treated with liquid ammonia and the ammonia was removed by evaporation. When ammonia was removed with water, the cellulose I lattice was regenerated. In the presence of 23% NaOH, diffractograms indicated a significant decrease in order after a similar drop in temperature, but patterns were not of cellulose II until the NaOH was removed with water. Conversion to cellulose III or to cellulose II was achieved instantaneously when ammonia‐ and alkali‐impregnated fabrics were immersed in liquid nitrogen.
Origin and role of the luminescent species in the photo‐oxidation of commercial polypropylene
Authors: Allen N. S. , Homer J. , McKellar J. F. 
Published: April 2003

AbstractThe fluorescence and phosphorescence excitation and emission spectra of commercial polypropylene have been examined using a fully compensated spectrofluorometer. This has made possible the comparison of the excitation spectra of the polymer with model chromophores of those believed to be present in the polymer. The fluorescence emission is primarily associated with the presence of enone, and the phosphorescence with dienone chromophoric units. The behavior of the luminescent enones and dienones during irradiation under sunlight‐simulated conditions has also been examined. Possible mechanisms for the participation of these chromophoric units in the photo‐oxidation of polypropylene are discussed.
Fully ordered copolyhydrazides based upon bisacid A2
Authors: Lenk R. S. 
Published: April 2003

AbstractThe preparation of copolyhydrazides containing equimolar quantities of “bisacetyl A2” and terephthaloyl or isophthaloyl groups is described. The resulting copolymers were found to form clear colorless films which, when immersed in concentrated formic acid, softened but rehardened and turned white after subsequent immersion in water. The formic acid treatment did not bring about a morphological change from the amorphous to the crystalline state, but caused changes in the differential scanning calorimetry (DSC) traces which suggest that an α/β transformation had taken place. The possible nature of this transition is discussed. The results of tensile tests on cast film are given.
The influence of hydrophilic and hydrophobic domains on water wettability of 2‐hydroxyethyl methacrylate‐styrene copolymers
Authors: Okano Teruo , Katayama Masato , Shinohara Isao 
Published: April 2003

AbstractCooligomers and ABA‐type block copolymers composed of a hydrophilic monomer, 2‐hydroxyethyl methacrylate (HEMA), and a hydrophobic monomer, styrene, were synthesized to study the relation between their microstructure and hydrophilic and hydrophobic functions. Films of cooligomers and ABA‐type block copolymers were cast from DMF solutions at 40°C. The wettability, which was determined from the contact angle with water, increased considerably when HEMA mole fraction reached around 0.8 in the cooligomer system and around 0.9 in the ABA‐type block copolymer system. The microstructures of the copolymer films were observed by electron microscopy using the osmium tetroxide fixation technique. The morphologic change in the domain structure was observed at an HEMA mole fraction of about 0.8 in the cooligomer system and about 0.9 in the ABA‐type block copolymer system. It is suggested that hydrophilic and hydrophobic functions are largely influenced by the state of aggregation of each segment, that is, the size and geometry of the hydrophilic and hydrophobic domains.
Force–displacement evaluation of macromolecular materials in flexural impact tests. II. Influence of rubber content, degree of grafting, and temperature on the impact behavior of ABS resins
Authors: Rink M. , Riccò T. , Lubert W. , Pavan A. 
Published: April 2003

AbstractThe impact behavior of ABS (acrylonitrile–butadiene–styrene) resins was studied by measuring the force–deflection curve generated during flexural impact tests. Each curve is characterized by a limited number of significant parameters. Their dependence on the following constitutive or ambient variables was investigated: content of butadiene rubber, degree of grafting of acrylonitrile and styrene onto polybutadiene, and temperature. The results are analyzed phenomenologically and are tentatively interpreted in the light of possible micromechanical mechanisms.
Microstructure and its relationship to deformation processes in amorphous polymer glasses
Authors: Wellinghoff Stephen T. , Baer Eric 
Published: April 2003

AbstractThe microdeformation morphology of a number of vinyl polymers with bulky side chains (type I) and arylene polymers with flexible oxygen linkages (type II) was studied by electron microscopy. The polyarylenes crazed only near the glass transition while the polyvinyls exhibited a crazing regime that extended to liquid nitrogen temperatures. In addition significantly less plastic strain was localized in type II glass crazes relative to those in type I glasses. In compatible blends of polystyrene (PS) and 2,6‐dimethyl poly(phenylene oxide) (2MPPO), ca. 30% 2MPPO was sufficient to induce a transition from type I to type II crazing behavior. Small amounts of PS suppressed the low‐temperature 2MPPO β relaxation but enhanced the intermediate transition of 2MPPO at higher temperatures. Blending increased the conformational energy of the 2MPPO chain and improved interchain packing. The propensity for the polymer glass to form sharp shear bands at the expense of diffuse bands was increased by a decrease in the conformation energy of the polymer chain and an improvement in the glassy state packing.
Synthesis of metal‐containing cured resins from divalent metal salts of mono(hydroxyethyl) phthalate, anhydrides, and bisepoxides
Authors: Matsuda Hideaki 
Published: April 2003

AbstractSynthesis of novel metal‐containing cured resins based on divalent metal salts of mono(hydroxyethyl) phthalate were investigated by the metal salt–anhydride–bisepoxide reactions. As the anhydrides, maleic anhydride (MA) and hexahydrophthalic anhydride (HPA) were used, and hexahydrophthalic acid diglycidyl ester (HPDG), bisphenol A diglycidyl ether (BADG), and ethylene glycol bis(glycidyl phthalate) (EBGP) were the bisepoxides used. The reactions were further studied in model reactions using the Ca salt of monoethyl phthalate. The metal carboxylate groups of the metal salts catalyzed the reactions. The reactivity of the bisepoxides decreased in the order HPDG ≫ BADG > EBGP, and MA was more reactive than HPA. Some of the metal‐containing cured resins obtained showed excellent physical properties. Resistance to chemical attack and boiling water, thermal behavior, and electrical resistance are also discussed.
Thermal degradation of polymers. Part XX. The effect of thermal ageing on thermal diffusivity and hardness of polyquinazolones
Authors: Chan H. S. O. , Still R. H. 
Published: April 2003

AbstractPre‐polymers prepared from 4,4′‐diaminodiphenyl‐3,3′‐dicarboxylic acid and aromatic diacetamido compounds have been cyclized under optimized conditions. The thermal diffusivity and hardness of these materials have been evaluated. The effect of thermal ageing on these parameters and weight loss has also been investigated. Changes in these parameters have been related to the possible structural changes occurring within these systems. These changes are discussed in terms of the potential use of these materials in tribological applications.
Effect of winding speed on the physical structure of as‐spun poly(ethylene terephthalate) fibers, including orientation‐induced crystallization
Authors: Heuvel H. M. , Huisman R. 
Published: April 2003

AbstractAs‐spun fibers of poly(ethylene terephthalate), PET, made at winding speeds ranging from 2000 to 6000 m/min exhibit quite different physical structures. Yarns wound at relatively low speeds are amorphous, whereas those spun at high speeds contain well‐developed crystals of closely packed molecules. In this study the structures have been characterized by means of various techniques such as differential scanning calorimetry, x‐ray diffraction, density, and pulse propagation measurements. Based on the results obtained, an arrangement of the molecules in the various yarns is proposed. It is shown that these arrangements can account for the extreme wide variety in contraction behavior found experimentally. Finally, the results obtained are compared with those of other investigations into orientation‐induced crystallization.
X‐ray diffraction orientation studies on blown polyethylene films. III. High‐stress crystallization orientation
Authors: Maddams W. F. , Preedy J. E. 
Published: April 2003

AbstractX‐Ray diffraction orientation measurements have been made on a wide range of films blown from three high‐density polyethylenes, to determine more precisely the conditions which lead to the high‐stress crystallization type of orientation. The most extensive measurements relate to films from Hostalen GM 9955F; the results show that there is a very wide range of orientational behavior. Under very low‐stress conditions there is almost pure a‐axis orientation; with very high stress there is substantial c‐axis orientation, both with reference to the machine direction. Commercial blowing conditions give rather high stress and the a axis is inclined at 60° to 70° to the machine direction in the sheet‐normal—machine‐direction plane. Calcium stearate, used to improve the surface finish, increases the stress for a given set of machine conditions and, of these, a high draw ratio and a low extrusion temperature are most effective in promoting high‐stress crystallization. The less extensive results for an experimental Rigidex grade and Shell LPPE 040 fit into this overall pattern; for a given set of blowing conditions they have lower stress than the Hostalen polymer. Commercial blowing conditions give an a‐axis inclination of about 45°.
Plasma‐deposited polymer films. I. Low‐angle x‐ray study
Authors: Havens M. R. , Mayhan K. G. , James W. J. , Schmidt P. 
Published: April 2003

AbstractA low‐angle x‐ray scattering technique has been applied to determine the submicrostructure of plasma‐formed polyethylene and polystyrene. The plasma‐formed polymers appear to closely approximate a “filler—binder” structure where polymer spheres constitute the filler material and a lower‐density polymer, the binder. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) micrographs confirm the spherical diameters predicted by the low‐angle x‐ray scattering data.
Heavy metal ion scavengers from cyanuric chloride
Authors: Kaeriyama Kyoji , Rokusha Tadanori , Naomi Keiko 
Published: April 2003

AbstractCyanuric chloride was reacted with polyamines and thiourea, and subsequent hydrolysis of the isothiouronium salt yielded amine polymers with divalent sulfur. The polymers scavenge cupric, cadmium, lead, and mercuric ions from considerably concentrated hydrogen chloride solutions, and they were compared with polystyrene—sulfonic acid resin. Zinc, cobaltous, and nickel ions are adsorbed only at relatively high pH (4.8–6.8). Removal of cupric, cadmium, and mercuric ions is not affected by the addition of sodium chloride.
Fine structural changes in native and mercerized fibrous cellulose brought about by ethylenediamine and methyl alcohol
Authors: Chidambareswaran P. K. , Sreenivasan S. , Patil N. B. , Lokhande H. T. , Shukla S. R. 
Published: April 2003

AbstractX‐Ray diffraction (XRD) studies were made on native as well as mercerized ramie and cotton fibers after swelling them in ethylenediamine (EDA) solutions and washing out the swelling agent using methyl alcohol (MeOH). These treatments are shown to convert the cellulose I and II lattices into cellulose IIII and IIIII type lattices, respectively. Treatment of the IIII and IIIII samples in boiling water or hydrochloric acid results in reconversions of their crystal lattices into the respective parent types. Alkali treatment causes a III → II type conversion. Studies using alkali‐swollen fibers as well as fibers of different lateral order as starting materials indicate the importance of the structural organization in the cellulosic materials in the production of the cellulose III lattices. Possible mechanisms involved in the lattice transformations in cellulose brought about by the EDA and MeOH treatments are discussed.
Corona treatment changes some physical properties of cellulose
Authors: Venkateswaran A. , Desai R. L. 
Published: April 2003

AbstractMoisture absorption, dielectric properties, and x‐ray crystallinity of cellulose handsheets and deacetylated cellulose acetate films have been determined. The moisture absorption of the treated samples was lower than that of the controls. Further, the changes of the electrical properties of the treated samples agreed with the observed decrease in the moisture absorptions of the treated samples: no significant change in their crystallinity was noted.
Lewis acid on polymeric carriers as initiators in carbenium ion polymerizations: Polystyrene–aluminum chloride
Authors: Sivaram S. , Naik K. M. 
Published: April 2003

AbstractThe scope and limitations of aluminum chloride bound to polystyrene matrix as an initiator in carbenium ion polymerizations have been studied and compared with the performance of free aluminum chloride in homogeneous solutions. Under comparable conditions, the resin‐bound aluminum chloride is less efficient than free aluminum chloride; however, the molecular weights of polymers obtained from both classes of initiators are essentially similar.
Polyester–polycarbonate blends. II. Poly(ethylene terephthalate)
Authors: Nassar T. R. , Paul D. R. , Barlow J. W. 
Published: April 2003

AbstractMelt blends of polycarbonate and poly(ethylene terephthalate) were prepared and examined for their transitional behavior by thermal analysis and dynamic mechanical testing. A single Tg was observed for compositions containing more than 60%–70% PET by weight while compositions below this range showed two glass transitions. From this it is concluded that PC and PET are completely miscible in the amorphous phase for PET‐rich compositions, whereas PC‐rich blends separate into two amorphous phases which apparently contain both components. Melting point and crystallization behavior are conssistent with these conclusions and suggest that very little if any interchange reactions occur between the ester and carbonate groups during melt mixing.
Emulsion of polyurethane having thermosetting properties. I. Preparation
Authors: Matsuda Kazuo , Ohmura Hidemasa , Tanaka Yoshiaki , Sakai Takeyo 
Published: April 2003

AbstractA method of preparation of an urethane emulsion which provides thermosetting film is described here. By reacting a urethane prepolymer containing terminal isocyanate groups with diethylenetriamine in the presence of ketones, poly(urethane‐urea‐amine) was prepared. In other organic solvents, however, gelation occurred immediately and preparation of polyurethane‐urea‐amine was not successful. The function of ketone was ascribed to the tentative formation of a Schiff base between the primary amino group of diethylenetriamine and ketone in situ, and the reaction of primary amine with isocyanate was partly masked to prevent gelation. Then the free amino group is generated when the polymer is treated with epichlorohydrin and the reaction occurs between them. After the solution was neutralized with an aqueous acid, the solvent was removed in vacuo to give a stable self‐emulsifiable thermosetting urethane emulsion. Typical mechanical properties of film from this urethane emulsion are also given here.
Fiber–fiber coefficient of friction: Effects of modulus and tan δ
Authors: Prevorsek D. C. , Sharma R. K. 
Published: April 2003

AbstractThe technologically important studies on rubber friction and wear give strong support to rubber friction being a viscoelastic phenomenon. However, the basic concepts and conclusions derived from such studies appear to have general validity. Fiber‐to‐fiber friction studies are carried out on a number of polymeric flaments with a view to establishing the relationships between fundamental mechanical properties such as modulus, tan δ, and the coefficient of friction. The relationship between these three quantities is expressed by an equation. The results show that with these fibers adhesive contribution to friction is negligible and that temperature and humidity variations in end uses have a much more important effect in frictional properties than changes in draw ratio, heat setting, and so on.
On free volume of polymers above the glass transition
Authors: Aharoni S. M. 
Published: April 2003

AbstractThe magnitude of the activation energy for diffusion, ED is shown to be inversely dependent on the fractional free volume of the polymer above Tg. From the proportionality of ED above and below Tg, the magnitude of ED below Tg is also inversely dependent on the free volume in that temperature range. While this correlation holds very well for our determinations of fractional free volume above Tg it does not correlate with the Simha‐Boyer fractional free volume below Tg, contrary to expectations.
Characterization of water structure in cellulose acetate membranes by calorimetric measurements
Authors: Burghoff H.‐G. , Pusch W. 
Published: April 2003

AbstractThe heat capacities of homogeneous and asymmetric cellulose acetate membranes have been measured at different water contents within the temperature range of −40 to +20°C. The experimental heat capacity–temperature curves were verified by DTA measurements within a temperature range of −120 to +20°C. The results for the partial heat capacity of water within the membranes as well as for the heat of fusion were interpreted by assuming two different states of water—unfreezing bound water due to a sorption process and unbound water due to capillary phenomena, which freezes with a freezing point depression and a reduced heat of fusion.
Adhesion of evaporated metallic films onto polyethylene and poly(tetrafluoroethylene): Importance of surface crosslinking
Authors: Vogel S. L. , Schonhorn H. 
Published: April 2003

AbstractNi, Fe, Ti, Al, Au, and Cu were each evaporated and deposited onto both sides of polyethylene and poly(tetrafluoroethylene) (PTFE) films. Adhesive joint strengths of the different metal–polymer–metal composites were compared and subsequent surface modifications due to metalization were investigated. Studies show no change in wettability of polyethylene or PTFE after a metal layer was deposited onto their surfaces and subsequently removed. There was also no evidence of oxidation or unsaturation of the surface. Gel fractions of polyethylene show a definite correlation between joint strength and crosslink at the surfaces of the different metal–polymer composites. Metals forming the strongest joints with polyethylene yield the greatest amount of crosslinking. Conversely, metals forming the weakest joints result in the least amount of crosslinking.
Polyester–Polycarbonate blends. III. Polyesters based on 1,4‐cyclohexanedimethanol/terephthalic acid/isophthalic acid
Authors: Mohn R. N. , Paul D. R. , Barlow J. W. , Cruz C. A. 
Published: April 2003

AbstractMelt blends of polycarbonate with Kodel, a homopolyester formed from 1,4‐cyclohexanedimethanol and terephthalic acid, and with Kodar, a copolyester formed by replacing some of the terephthalic acid with isophthalic acid, were prepared and their transitional behavior were examined by thermal analysis and dynamic mechanical testing. Blends formed with either polyester were found to have a single Tg over the entire compositional range. Single composition‐dependent α‐ and β‐relaxation temperatures were also observed for blends made with either polyester at all compositions. From these data it is concluded that both Kodel and Kodar blends with polycarbonate form miscible amorphous phases. The role of ester–carbonate interchange reactions during melt mixing was experimentally examined and found to be unimportant, from which it is concluded that the observed miscible phase formation is due to physical interactions between the blend components.