bluuebunny/crossref_metadata_2025_split huggingface dataset:
Grafting of acrylate monomers in cotton fabrics
Authors: Negishi Michiharu , Nakamura Yoshio , Kakinuma Toshiko , Iizuka Yuriko 
Published: April 2003

AbstractThe graft copolymerization of acrylate monomers, methyl, ethyl, n‐propyl, and n‐ or isobutyl, in cotton fabrics was carried out in the aqueous emulsion system by the ceric ion method. The rate of grafting decreases with increasing length of the ester group. The maximum improvement of dry crease recovery, thus raising its value, increases with increasing graft‐on shifts towards the higher extents of grafting, and with decreasing second‐order transition temperature of graft polymer. The improvement of wet crease recovery, equilibrated in the presence of a wetting agent, is always greater than that in the dry crease recovery even when the hydrophobic propyl or butyl acrylate‐grafted cotton levels off with increasing graft‐on. The improvement of crease recovery was explained by the stabilization of the opened fiber structures by grafting with acrylates, especially those having bulky ester groups, the entangled crosslinking between the graft polymers or the graft polymers and cellulose chains, and the consequently developed elastomeric or swelling, elastomeric behaviors due to the segmental movements in the amorphous regions of graft copolymer. Furthermore, from the measurements of water imbibition and repellency, moisture regains, tensile properties, stiffness, flex abrasion, and thermosetting properties, it has been concluded that the improvements of physical properties are remarkable in the propyl or butyl acrylate‐grafted cotton.
Barus effect in filled polymer melts
Authors: Newman Seymour , Trementozzi Quirino A. 
Published: April 2003

AbstractThe influence of fillers on the post‐extrusion swelling (Barus effect) of polymer melts is explored with the use of three model fillers in poly(styrene–acrylonitrile). The filler effect is shown to be more complex than simple dilution of the polymer. The role of such factors as melt rigidity, tendency toward plug flow, trapping of matrix in filler aggregates, and filler migration are considered.
Polyurethanes as cryogenic adhesives
Authors: Sandler Stanley R. , Berg Florence R. 
Published: April 2003

AbstractPolyurethanes containing the polyether backbone were found to give superior adhesives at cryogenic temperatures as compared to epoxy resins. However, the adhesives showed poor performance at 250 and 400°F. The adhesives were prepared from 2,4‐toluene diisocyanate (TDI)‐terminated polyether polyols and cured with 3,3′‐dichloro‐4,4′‐diaminodiphenylmethane (MOCA, du Pont). The addition of free TDI causes an increase in elevated temperature strength when an equivalent amount of MOCA was used.
Polarization‐optical investigation of normal and shear stresses in flow of polymers
Authors: Brizitsky V. I. , Vinogradov G. V. , Isaev A. I. , Podolsky Yu. Ya. 
Published: April 2003

AbstractA method has been suggested for calculating the first difference of normal stresses characterizing the flow of polymers at high shear stresses. The calculations are based on the results of rheooptical measurements in a slit of rectangular cross section. It has been found, for several samples of high molecular weight polybutadienes and polyisoprenes, that the flow behavior of the representatives of the given polymer homologous series having different molecular weights is characterized by a general relationship between the first normal stress differences and the shear stresses in those cases where the polymers are characterized by narrow molecular weight distributions. It has also been established that the first normal stress difference sharply increases in the region of shear stresses which immediately precedes the spurt—a jumpwise increase of the flow rate at a certain critical value of shear stress; while for polymers of wide molecular weight distribution the increase of the normal stress difference in the region of high values of shear stresses is retarded. Equilibrium swell of the extrudate has been measured and the first normal stress difference determined by the rheo‐optical method has been found to agree satisfactorily with the values calculated from the swelling ratios according to theoretical models.
Studies on melt spinning. VI. Simulation of draw resonance using Newtonian and power law viscosities
Authors: Ishihara Hideaki , Kase Susumu 
Published: April 2003

AbstractDraw resonance, a periodic variation of spin line diameter in unstable melt spinning, was measured for its wave form under 34 different spinning conditions for PET and PP. In and attempt to simulate the measured wave form, the equations of continuity and momentum for the isothermal melt spinning of power law fluids were solved for their limit cycle solutions expressed in the time variations in the cross‐sectional area at the take‐up. Power law exponent p and draw down ratio ψw uniquely define the solution. Theoretical curves were superposed on the experimental amplitude‐versus‐ψw diagram and oscillation period‐versus‐ψw diagram to assign p value to each experimental point. Excellent agreement between theory and experiment was obtained with PET in that p values were nearly independent of ψw and of the diagram used in the determination of the p value, amplitude diagram, or oscillation period diagram. Motion pictures (16mm) of the side profiles of the pulsing spinline showed good agreement with the theoretical side profiles constructed from the corresponding limit cycle solution. It was proposed that the stability of melt spinning has no direct equivalence to the spinnability of fluids.
Increase of gold–Teflon FEP joint strength by removal of deposited aluminum prior to gold deposition for electret applications
Authors: Roberts R. F. , Ryan F. W. , Schonhorn H. , Sessler G. M. , West J. E. 
Published: April 2003

AbstractA new method is described for bonding gold to Teflon FEP, yielding high joint strength without affecting the electrical properties of the virgin polymer material. The method consists of depositing a 1000‐Å aluminum layer onto the Teflon by evaporation, removing it by washing the sample in dilute sodium hydroxide, followed by deposition of gold by evaporation. The tensile shear strength of this composite is in excess of 80 kg/cm2, approaching the cohesive strength of Teflon. The desirable electrical properties of Teflon FEP, as measured by isothermal charge decay and thermally stimulated currents methods, are preserved by this method. X‐Ray photoelectron (ESCA) spectra suggest that the modified wetting characteristics and enhanced joint strengths can be attributed in part to the existence of a thin layer of oxygen‐containing hydrocarbon material on the surface of aluminum‐treated Teflon FEP.
Permeabilities to salts and water of macrocyclic polyether–polyamide membranes
Authors: Shchori Ehud , Jagur‐Grodzinski Joseph 
Published: April 2003

AbstractThe polyether–polyamide (PC‐6) strongly absorbs sodium salts from their aqueous solutions. Membranes based on PC‐6 and on its polymeric alloys with poly(vinylpyrrolidone) (PVP) are, however, much more permeable to water than to salts. The membrane permselectivity is due to the low mobility of the absorbed salts. Desorption experiments were conducted to determine the values of the diffusion coefficients of the sodium ions in the investigated membranes. They were found to vary from 5 × 10‐12 cm2/sec in loose PC‐6 membranes to 1.7 × 10‐9 cm2/sec in the polymeric alloy containing 30% PVP. Water permeation experiments with the alloy membranes yielded values of the diffusion coefficients in the range of 2–5 × 10‐7 cm2/sec. The apparent “energy of activation of the diffusion” of sodium ions in such membranes was found to be essentially indentical (∼12 kcal) with the energy of activation of the decomplexation of the sodium–“crown” complex. The ramifications of the proposed “site to site jump” diffusion mechanism were discussed. The permeability characteristics of PC‐6 membranes were found to be strongly affected by their “history.”. The observed phenomenon was explained in terms of reversible changes in the structure of the polymeric network, in the presence and in the absence of the absorbed salts. It has been found that PVP has a stabilizing effect on the permeability characteristics of the membranes. Reverse osmosis experiments indicated that their intrinsic osmotic characteristics seem to be superior to those of the commercially used materials. Their salt rejections are in the range of 95–99.5%, and their permeabilities to water are at least one order of magnitude higher than those of the unmodified aromatic polyamides.
Viscoelastic characterization of PVC plastisol melts for foam applications
Authors: Nakajima N. , Ward D. W. , Collins E. A. 
Published: April 2003

AbstractMelt rheology and its time‐temperature dependence have long been known to be fundamental properties associated with satisfactory expansion characteristics in vinyl foam. Since much is known about the relationship between rheology and material variables like polymer morphology and system composition, adequate rheological characterization should be quite helpful in polymer design and plastisol compounding.Earlier attempts to study the melt rheology of plasticized PVC foam systems were only partially successful because instrument limitations required that the material be studied at too high shear rate or temperature, or that behavior of specific compositions be extrapolated from data obtained at considerably higher plasticizer level.This paper deals with measurement of the viscoelastic behavior of melts from actual azodicarbonamide foam compositions. The Rheometrics Mechanical Spectrometer was used in the orthogonal mode to study both elastic modulus and loss modulus (viscosity) in the range of shear rates and temperatures which actually occur during commercial utilization of PVC foam compounds. The effects of changing vinyl resin types and plasticizer types and levels were explored.
Pulse propagation in polyester–solvent systems
Authors: Weigmann H.‐D. , Ribnick A. S. 
Published: April 2003

AbstractThe propagation of sonic pulses through solvent‐swollen polyester yarns has been investigated. A discontinuity is observed in the temperature dependence of the pulse transit time which has been associated with the on set of the glass transition of the polyester–solvent system. Good agreement is reached for several systems with an extrapolated zero shrinkage temperature obtained from dynamic shrinkage determination of the filament in the appropriate solvent. The agreement between the two methods suggests that an interaction parameter for the polyester–solvent system is measured which must ba associated with the onset of its glass transition.
Tough, transparent heat‐ and flame‐resistant thermoplastics via silicone block‐modified bisphenol fluorenone polycarbonate
Authors: Kambour R. P. , Corn J. E. , Miller S. , Niznik G. E. 
Published: April 2003

AbstractBisphenol fluorenone carbonate–dimethylsiloxane block polymers have been synthesized by interfacial condensation of phosgene with various mixtures of BPF‐endcapped silicone oligomers and free BPF or its monosodium salt. The multisequence block polymers described here contain 7% to 27% silicone consisting of blocks of number‐average degree of polymerization 10 to 40. Cast films are clear and colorless. Two glass temperatures are evident in each resin, one at about −100°C for the silicone microdomains and one at temperatures as high as 275°C for the polycarbonate matrix. While BPF polycarbonate is brittle, block polymers with as little as 10% silicone yield by shear deformation before breaking. Ultimate elongations are increased by preorientation at silicone contents above 15%. At temperatures far removed from BPF carbonate domain Tg's, both modulus and yield stress decrease with increasing silicone content, independent of block length, in a manner rationalized quantitatively by hard phase–soft phase continuum models. Ultimate tensile elongation, impact toughness, and plane strain stress intensity factors increase with silicone content, through a stress whitening mechanism. At higher silicone contents, shear deformation enhances tensile elongation and impact toughness. Heat distortion temperatures of 200°C or more are achieved. Flame resistance exceeds that of any known nonhalogenated resin. The resins are extrudable and injection moldable with only minor changes in color, transparency, and strength properties. Resins with 15% to 20% silicone can have a balance of properties that makes them attractive as tough, transparent heat‐ and flame‐ resistant engineering plastics.
The near‐infrared spectra of polymers
Authors: Crandall Elbert W. , Jagtap Ashvin N. 
Published: April 2003

AbstractA series of step reaction polymers have been prepared and studied as melt films or in solution in the overtone region and the combination region of the near‐IR. Systems containing aryl rings show bands in the 2.13‐ to 2.16‐μm region which are not observed in those systems not having aryl rings. Polyester, polyamide, and urea‐formaldehyde polymers show carbonyl, hydroxyl, and NH overtones. Polyurethanes show only the intense band of NH, in the 2.0‐ to 2.1‐μm region. Ureaformaldehyde and polyamides show this same band. Relative band intensities were compared to the first overtone of CH which appears at 1.67–1.72 μm. In this way, polymers can be compared in a quantitative manner, both with respect to reaction conditions and effect of heat curing.
Diffusion with simultaneous reaction of reactive dyes in cellulose
Authors: Motomura Hiromi , Morita Zenzo 
Published: April 2003

AbstractThe theoretical equations which described the concentration profile of immobilized species of reactive dyes in the substrate were derived from the diffusion equation with the chemical reaction of first‐order or pseudofirst‐order. The theoretical profiles in the substrate described by the equations were discussed. The larger the diffusion coefficient D of active species and the smaller the reaction rate constant k, the deeper is the penetration of the immobilized and active species of reactive dyes into the substrate. The method of estimating D and k from the diffusion profiles of both species obtained by means of the method of the cylindrical cellophane film roll was described. The diffusion coefficients of the hydrolyzed species of C.I. Reactive Orange 1 and Red 1 were nearly constant in all the pH values examined. The concentration profiles of both the species of Orange 1 at pH 8.8 were identical with the theoretical ones; while the profiles of immobilized species of Red 1 at pH 10 and of Orange 1 at pH 12 agreed with the theoretical ones and those of active species did not because of the hydrolysis. The diffusion coefficients of active species of these dyes at these pH ranges were smaller than those of the hydrolyzed species.
Graft copolymers from thiolated starch and vinyl monomers
Authors: Trimnell D. , Stout E. I. , Doane W. M. , Russell C. R. 
Published: April 2003

AbstractThiol starches of degree of substitution (D.S.) 0.005–0.162 were prepared by displacing starch tosyloxy groups with xanthate and treating the resulting xanthate esters with either sodium hydroxide or sodium borohydride. Acrylonitrile, styrene, acrylamide, acrylic acid, and dimethylaminoethyl methacrylate were grafted onto the thiol starches with hydrogen peroxide as initiator. The peroxide caused both grafting of monomer and coupling of thiol groups to disulfide. Treating graft copolymers with sodium borohydride regenerated thiol groups from disulfide groups so that the grafting sequence could be repeated. By regenerating the thiol groups and repeating the grafting steps, high add‐on and high‐frequency starch graft copolymers were prepared. During four grafting sequences, acrylonitrile reacted with D.S. 0.162 thiol starch to give graft copolymers that contained increasing amounts of polyacrylonitrile (46.0–66.5%). Grafting frequency increased from 183 to 71 anhydroglucose units (AGU)/graft, while molecular weights of the grafted chains ranged between 20,000 and 25,200. The final product was hydrolyzed with potassium hydroxide solution to a copolymer, which absorbed up to 400 ml water per gram. Styrene was grafted onto thiol starch to give products containing 34.4–69.5% polystyrene with 986–3520 AGU/graft and having molecular weights of grafted chains between 276,000 and 364,000. Graft copolymers containing 48.9% polyacrylamide, 21.2% poly(acrylic acid), and 77.7% poly(2‐methacryloyloxyethyldimethylammonium acetate) were obtained under similar conditions.
Thermal properties of metal‐filled epoxies
Authors: Papanicolaou G. C. , Paipetis S. A. , Theocaris P. S. 
Published: April 2003

AbstractThermal expansion coefficients and glass transition temperatures for metal–epoxy composites were determined experimentally. Results were in fair agreement with existing theories when certain fundamental assumptions were fulfilled. The effects of filler content and particle size as well as of adhesion between matrix and filler particles were investigated. The latter, in particular, was found to be of cardinal importance for the properties examined in the present work.
High‐speed gel permeation chromatography. A study of operational variables
Authors: Mori Sadao 
Published: April 2003

AbstractSystematic studies of operational variables affecting GPC separation using μ‐Styragel of nominal porosity 106, 105, 104, and 103 Å are reported. The dependences of (1) flow rate, (2) injection volume, and (3) concentration on elution volume (Ve), the theoretical plate number (N), and peak width at half‐height were examined. The values of Ve changed with changing (1), (2), and (3). The values of N were inversely proportional to the root of flow rate. The relation between sample load and N showed that lower concentration and larger injection volume were desirable for N than the opposite. The concentration dependence for high‐speed GPC was significantly higher than classical low‐speed GPC. The methods of minimizing the effects produced by the individual variables and the optimum operational conditions are discussed. Recommended operational conditions are as follows: flow rate, 1 to 2 ml/min; injection volume, 0.1 ml; sample concentration, below 0.4% (or if injection volume 0.5 ml, sample concentration below 0.1%).
Noble gas permeability of polymer films and coatings
Authors: Hammon H. George , Ernst Klaus , Newton John C. 
Published: April 2003

AbstractPermeabilities of noble gases, particularly argon, krypton, and xenon, were measured through a number of polymer films and coatings. Extrapolation of the log of the permeation coefficient versus the square of the gas molecular diameter was used to estimate radon permeability. An equation has been developed that can predict permeability to these noble gases as a function of the base polymer structure of the coating.
Preparation and properties of polycarbodiimides
Authors: Alberino L. M. , Farrissey W. J. , Sayigh A. A. R. 
Published: April 2003

AbstractA series of polycarbodiimides was prepared from isocyanates using 1‐phenyl‐3‐methyl‐2‐phospholene‐1 oxide as catalyst. The molecular weight of the series was varied by employing controlled amounts of phenyl isocyanate as a terminating agent. The resultant polymers showed improved processing over very high molecular weight unterminated polymer, while still maintaining good thermal stability and equivalent mechanical properties. A study of the viscoelastic properties of these polymers using modulus–temperature plots showed that the materials underwent a crosslinking reaction at elevated temperatures (200–250°C). These reactions could be explained on the basis of a model, diphenylarbodiimide, and most likely include the formation of carbodiimide dimers and trimers.
On the structure of concentrated cellulose acetate solutions
Authors: Kunst B. , Vajnaht Z. 
Published: April 2003

AbstractThe supermolecular structure of cellulose acetate membrane casting solutions was determined by measuring their rheological behavior. The method was applied to both clear and turbid casting solutions. The resulting data on activation energy of viscous flow are shown to depend on the cellulose acetate content of the casting solution and on the nature of solvent used. The separation properties of the prepared asymmetric membranes determined by reverse osmosis testing indicate a good correlation with the data obtained by the rheological measurements of the casting solutions. The latter can, therefore, be used as a practical tool for the investigation of early stages in the asymmetric membrane formation process.
Dyeing behavior of swollen cotton fibers and swelling mechanisms of intra‐ and intercrystalline swelling agents
Authors: Lokhande H. T. 
Published: April 2003

AbstractDyeability was used to study the swelling mechanisms of intra‐ and intermicellar swelling agents on cotton cellulose. Reactive and direct dyes were used for dyeing, and zinc chloride, ethylenediamine (EDA), and morpholine were used for swelling reactions. Changes taking place in the accessible regions as a result of swelling were determined by moisture regain, acid hydrolysis, formylation, and the lateral order distribution in the fiber structure. The results indicate that the intracrystalline swelling agents, viz., zinc chloride and EDA, induce specific changes in the accessible portions of the fiber. The accessible portion produced by the inorganic swelling agent has a more open structure than the disordered region produced by the EDA treatment. The distinctive nature of the accessible portions in swollen cotton fibers treated with the two reagents was reflected in all the properties studied. This was attributed to the different mechanisms of swelling and decrystallization of cotton fibers by zinc chloride and EDA. Morpholine was shown to bring about considerable changes in the accessible portions of the cotton fiber which were responsible for increased dyeability with reactive dyes, and was also shown to increase the amount of “truly” accessible regions by breaking the “imperfect crystals” in the disordered regions as well as on the surface of crystallites.
Viscosity index. I. Evaluation of selected copolymers incorporating n‐octadecyl acrylate as viscosity index improvers
Authors: Jordan Edmund F. , Smith Steven , Koos Ronald E. , Parker Winfred E. , Artymyshyn Bohdan , Wrigley A. N. 
Published: April 2003

AbstractCompositionally and structurally varied copolymers all containing n‐octadecyl acrylate were prepared and evaluated as viscosity index improvers in a common base oil under conditions of low shear. Systems evaluated over a range of copolymer and blend composition were: copolymers of n‐octadecyl acrylate with, respectively, methyl methacrylate, 2‐ethylhexyl acrylate, and n‐dodecyl acrylate; and homopolymers of poly(n‐octadecyl acrylate), prepared with a wide range of molecular weights. Properties were compared with those of blends of commercial methacrylate copolymers (acryloids) which had been freed of their entraining liquid. Mixtures of base oil with copolymers of n‐octadecyl acrylate and methyl methacrylate, compared at fixed SAE viscosities, were the most efficient of all blends studied. They had the smallest rate of change of viscosity with temperature (as measured by their ASTM slopes), particularly in the composition region of incipient polymer precipitation at room temperature. Efficiency of certain of these composition was somewhat greater than that of the acryloids. A parameter that related concentration and weight‐average molecular weight was used to correlate all of the data for ASTM slope and viscosity. Empirical relations developed by using this parameter enabled rheological data to be estimated that agree within 6% of experimental values for the case of thermodynamically good base oil solvents. These data demonstrated the relatively small contributions of copolymer structure to viscosity index improvement.