bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of the chemical modification of cotton fabric with propane sultone and through grafting with acrylonitrile on the dyeability with basic dyes
Authors: Sabaa M. W. , Watamoto H. , Sakamoto M. , Furuhata K. 
Published: April 2003

AbstractThe sulfonated cotton fabrics (sulfur content: 0–0.52%), obtained by the treatment with propane sultone, were subjected to graft copolymerization with acrylonitrile. The values of the % graft of the sulfonated cotton fabrics were higher than those of untreated cotton fabrics. The sulfur contents of the sulfonated cotton fabrics, however, affected little the % graft. The sulfonated and grafted cotton fabrics absorbed basic dyes, Methylene Blue, Diamond Green, and Cathilon Red. The color fastness of these dyes towards light from a Xenon lamp and towards ultraviolet radiation was significantly improved by the introduction of polyacrylonitrile onto cotton.
Infrared and liquid chromatographic characterization of epoxy cresol novolac‐phenol formaldehyde novolac‐tertiary amine resin systems
Authors: Belton D. J. , Sullivan E. 
Published: April 2003

AbstractThe subject of this paper is an infrared and liquid chromatographic characterization of epoxy molding compounds of importance in the microelectronic manufacturing industry. A complete infrared description of resin extracts from 4000 to 700 cm−1 is given for three nondisclosed commercial extracts via comparisons with model epoxy cresol novolac and phenol formaldehyde novolac resins and by observing those spectral alternations affected during cure. In addition, both the molecular weight distributions and the methodology of obtaining such for the resin and hardener components of the extracts are described. These results are based upon reversed phase liquid chromatography and infrared spectroscopic measurements. The analysis described in this paper demonstrates significant differences among materials that, by chromatography alone, appear to have only subtle variations in both the resin and hardener molecular weight distributions. These differences include not only the quantity of resin or hardener of a particular oligomeric molecular weight, but also the apparent resin‐to‐hardener stoichiometry of the combined system.
The effects of morphology and hygrothermal aging on water sorption and transport in Kapton® polyimide
Authors: Yang D. K. , Koros W. J. , Hopfenberg H. B. , Stannett V. T. 
Published: April 2003

AbstractA comparison of water sorption and diffusion behavior in 2 mil, as‐received, Kapton= Trademark of E.I. Dupont de Nemours Inc.
film, and in otherwise identical but hygrothermally aged samples, suggests chemical differences between the samples. These differences can be related to known polyimide chemistry and the specific history encountered by the samples. Although the sorption isotherms are similar for an as‐received 0.3 mil sample studied earlier and for the as‐received 2 mil samples studied here, the diffusion coefficient of water in the as‐received 2 mil sample is approximately 300% larger than in the as‐received 0.3 mil sample. This large effect is believed to be related to the presence of small, paracrystalline aggregates with large aspect ratios. Differences in orientation measured by birefringence for the two samples suggest that the barrier properties of Kapton® are strongly affected by the detailed morphological organization of the ordered aggregates. Comparison of the sorption isotherms for the as‐received and hygrothermally aged 2‐mil films suggests a significant increase in the hydrophillic nature of the aged film. This change is consistent with an apparent chemical reaction between water and uncyclized amic acid residues in the film. The tendency for water to cluster in as‐received Kapton® is essentially eliminated by the chemical modification associated with hygrothermal aging. The hygrothermal aging produces a dramatic reduction in the water vapor diffusion coefficient at low vapor activities but a rather modest change at high activities.
Polymer complex from copolymers of acrylonitrile and ionic vinyl benzyl compounds
Authors: Senuma Masao , Kuwabara Shigeru , Kaeriyama Kyoji , Hase Fumio , Shimura Yukio 
Published: April 2003

AbstractCopolymerization of sodium vinyl benzyl sulfonate (VBS) or vinyl benzyl trimethyl ammonium chloride (VBQ) with acrylonitrile (AN) gave polyelectrolytes of preferable solution viscosities. The blending of these two copolymers in N,N‐dimethyl formamide (DMF) produced polymer complexes with ionic linkages, of which the following properties were examined. The maximum in the tan δ temperature was increased by complex formation. Freundlich‐type dye adsorption and much better dyeability than on polyacrylonitrile was observed. Electric resistivity decreased with the introduction of ionic moiety. Permeability of water increased with the number of ionic sites. Homogeneous films could be cast from DMF and dimethyl sulfoxide (DMSO) solutions.
Changes of spin–spin relaxation time for EPR composites during mixing process
Authors: Furuta Motonobu , Hikasa Tadashi , Kato Eiichi 
Published: April 2003

AbstractThe changes of the mobility of rubber molecules for carbon black‐filled EPR composites during mixing process in an internal mixer have been elucidated from T2 measurement using pulsed nuclear magnetic resonance (NMR). The thickness of the tightly bound region which is formed by the direct interaction with carbon black was stabilized with mixing but the restriction of the molecular mobility increased with further mixing. The amount of the loosely bound region increased considerably throughout the mixing, indicating that this region is formed by entanglement and crosslinking of the molecules. T2 of the mobile region which is a predominant part in the composites is independent of the mixing time. EPR has the thinner tightly bound shell and longer T2s compared with EPDM, showing the effect of unsaturated bond in EPDM which can become a strong bond site with carbon black.
Physical properties of vinyl chloride‐propylene copolymers
Authors: Langsam Michael , Mango Philip A. 
Published: April 2003

AbstractThe polymerization conditions that control the physical properties of vinyl chloride‐propylene copolymers have been examined, and the interaction between these polymerization conditions and the melt rheology, intrinsic viscosity, and bound propylene level of the copolymer have been quantified into a series of process control relationships. The interaction between primary and secondary suspension systems have been optimized for these copolymers to maximize the resin porosity. Binary initiator systems have been identified to overcome the degradative polymer kinetics associated with propylene comonomer.
Gas transport in poly(vinylidene fluoride): Effects of uniaxial drawing and processing temperature
Authors: El‐Hibri M. J. , Paul D. R. 
Published: April 2003

AbstractThis paper reports on the gas sorption and transport properties of poly(vinylidene fluoride) (PVF2) and on the effects uniaxial drawing and processing temperature have on these properties. Sorption and transport were first examined for “as‐received” commercial Kynar PVF2 film at 35°C. This film was 54% crystalline by weight. Solubility, diffusion, and permeability coefficients were measured for He, H2, Ar, O2, N2, CH4, and CO2. The solubility coefficient and the diffusion coefficient D were correlated with the Lennard–Jones potential and mean molecular diameter of the gas, respectively. Uniaxial drawing of PVF2 films was performed up to a draw ratio of 3.7 and over the temperature range 75–140°C. Transport properties were correlated with the extent of draw and drawing temperature. The permeability P and D were found to significantly decline with uniaxial drawing; the magnitude of this effect was dependent on both the drawing temperature and the molecular size of the penetrant considered. Roduetions in P and D became progressively more pronounced with increasing molecular diameter and with decreasing drawing temperature (down to a limit of about 75°C), which reflects an increase in effectiveness of drawing at low temperatures. PVF2 films annealed above 75°C showed an increase in P and D as opposed to the effect of drawing. The solubility of various gases in PVF2 was not found to be sensitive to processing treatments such as drawing and annealing, in agreement with the relatively small changes observed in free volume. PVF2 films subjected to various treatments were characterized by DSC, density, birefringence, and dynamic mechanical measurements. Gas transport measurements appear to provide a more sensitive and hence more viable measure of the effectiveness of drawing than these other techniques. Drawing PVF2 in the melt state was found to increase P and D, in contrast with the effects observed for solid‐state drawing. The results have been interpreted in terms of existing theories on morphology and microstructure in semicrystalline polymers.
Polyethlene‐modified bitumen for paving applications
Authors: Jew P. , Shimizu J. A. , Svazic M. , Woodhams R. T. 
Published: April 2003

AbstractIn cold regions, transverse cracking of asphaltic paving materials is a serious problem which has not been completely resolved despite much effort. In this investigation, the low temperature stress–strain properties of bitumen containing dispersed polyethylene were measured over the temperature range from −40 to 0°C and compared with unmodified bitumen in an attempt to develop a tougher, more ductile crack‐resistant binder for paving materials. Several grades of polyethylene were individually dispersed in liquid, heated bitumen to produce therein colloidal suspensions of polyethylene. The viscosities of these suspensions were determined at various temperatures and concentrations for each grade of polyethylene. Despite rather large differences in composition, molecular weight, and crystallinity of the polyethylenes, the differences in viscosity at the same concentration were relatively minor. However, the viscosity was very sensitive to the polyethylene concentration and the mixture became difficult to process at concentrations greater than 10 percent by weight. Thesee hot mixtures were then cast into rectangular beams for flexural testing at temperatures below zero degrees Celsius. Near the optimum polyethylene concentration of 8 percent by weight, the bitumen mixture possessed increased flexural strength, increased flexural modulus, increased elongation, and increased fracture energ at temperatures near −30°C. In one example the energy to fracture was increased ninefold compared to a standard 80/100 pen. bitumen control at −20°C. Mix design results are presented for a typical aggregate and compared with a MTC HL4 hot‐mix paving formulation which is used extensively throughout Ontario. The polyethylene‐modified asphalt concrete mix displayed a curious increases in both the Marshall flow and the Marshall stability values. Dynamic mechanical measurements confirmed the expected increase in resilient modulus at temperatures above zero degrees Celsius. The Marshall briquets containing polyethylene also exhibited slightly greater wet strength retention after prolonged immersion in water. These observations are consistent with the published data for commercial Novophalt paving materials developed in Austria and predict that the use of polyethylene in asphaltic hot‐mix paving materials can extend service temperature range at both high and low temperatures, thereby simultaneously reducing both pavement distortion (rutting) and low‐temperature cracking, so that pavement lifetimes can be more than doubled. The cost of such modification can be substantially reduced if scrap or reclaim polyethylene is employed instead of virgin polyethylene. Dispersing agents, such as Shell Chemical Kraton G block copolymers were advantageously employed to control the emulsion stability, particle size, and compatibility of the dispersed polyethylene phase.
Phase behavior of blends of aliphatic polyesters with a vinylidene chloride/vinyl chloride copolymer
Authors: Woo E. M. , Barlow J. W. , Paul D. R. 
Published: April 2003

AbstractA series of aliphatic polyesters having CH2/COO ratios from 2 to 14 in their repeat units were blended with a copolymer of vinylidene chloride containing 13.5% by weight of vinyl chloride. Blends of polyesters having CH2/COO < 4 did not form completely miscible amorphous phases, whereas polyesters having CH2/COO ≥ 4 did form completely homogeneous amorphous phases for all temperatures below the decomposition point except for the polyester with CH2/COO = 14 which showed reversible phase separation on heating, i.e., lower critical solution temperature behavior. Interaction parameters were estimated by melting point depression and by analog calorimetry. The behavior reported here is qualitatively similar to that reported earlier for blends of aliphatic polyesters with poly(vinyl chloride), polyepichlorohydrin, polycarbonate, styrene–allyl alcohol copolymers, and the hydroxy ether of bisphenol A.
Mechanism and kinetics of the reaction of acrylic polyols with hexa (methoxymethyl) melamine
Authors: Collette J. W. , Corcoran P. , Tannenbaum H. P. , Zimmt W. S. 
Published: April 2003

AbstractNew procedures have been developed to study the mechanism and kinetics of the crosslinking of acrylic polyols with hexa (methoxymethyl) melamine. Both the rate of gel formation and alcohol release are found to be affected by the concentration and the nature of the catalyst and to be proportional to the hydrogen ion concentration. The rate of gel formation can be modeled by using the Miller and Macosko procedure with the input consisting of the polymer composition and the rate of release of reaction products. The correlation between calculated and experimentally determined quantity of gel formed is good when the reactions are slow, but becomes poor when gel formation is rapid, suggesting that the formation of large rings is favored by rapid reaction. The rate of gel formation shows much less variation among different polymer systems than does the rate of release of reaction products from the crosslinking reaction.
Epoxy thermosetting systems based on cycloaliphatic diamines
Authors: Sabra A. , Pascault J. P. , Seytre G. 
Published: April 2003

AbstractWe have investigated the reaction kinetics of a liquid prepolymer DGEBA with isophorone diamine (IPD) and menthane diamine (MNDA). IPD is 10 times more reactive than MNDA. With mixtures of these two hardeners we have the possibility to control the reactivity of the curing agent and the pot life of the system. The kinetic results can be described with a single conversion temperature‐phase diagram and interpreted with the classical autocatalytic epoxyprimary and secondary amine hydrogens addition. The differences between IPD and MNDA can be explained by the steric hindrance around the amine group of MNDA and also by the difficulty to obtain pure MNDA without oxidation.
Thermoinitiated cationic polymerization of epoxy resins by sulfonium salts
Authors: Morio Kazuhiko , Murase Hisashi , Tsuchiya Hiroshi , Endo Takeshi 
Published: April 2003

AbstractCatalytic activities of benzyl sulfonium salts with nonnucleophilic anions (BF4−,PF6−,AsF6−,SbF6−) for epoxy polymerization were examined. The order of reactivities correlated well with nonnucleophilicity of anions. Epoxy resins catalyzed by these salts are characterized by longer shelf‐life and shorter gel time at high temperature. Some physical properties of cured product were compared with those cured by a commonly used BF3 amine complex.
Rheological study of the isothermal reticulation of an epoxy resin
Authors: Harran Daniel , Laudouard Annie 
Published: April 2003

AbstractThe complex modulus of shearing G* = G' + jG″ was measured during the isothermal hardening of several epoxy resins. The gelation induces a slowing down of the rate of growth of viscous modulus ν″ = d(log G″)/dt between two zones where this rate is constant. This slowing down of growth rate varies with the temperature and is null for T = TC gel: ν″2 −ν″1 = K(1/TC gel −1/T). We have shown that the two phenomena of gelation and vitrification stay perfectly distinct at all temperatures and in particular at TC gel. So the decrease of the rate ν″ associated with gelation disappears at this temperature without the vitrification being responsible.
Thermophysical analysis of thermal polymerization of silica‐organic cladding for silica fibers
Authors: Ionov V. N. , Kashin V. V. , Perminova V. N. , Rusanov S. Ya. , Sysoev V. K. 
Published: April 2003

AbstractThe paper shows the advantages of graded furnaces for the thermal polymerization of a silica‐organic polymer cladding for silica fibers. Owing to the optimal longitudinal distribution of the heaters a fivefold increase of the fiber drawing speed can be achieved using heaters of the same lengths and power.
Flame retardation of poly(ethylene terephthalate) containing poly(4‐bromo styrene), poly(vinyl bromide), and poly(vinylidene bromide)
Authors: Day M. , Suprunchuk T. , Cooney J. D. , Wiles D. M. 
Published: April 2003

AbstractThe pyrolysis and gaseous combustion of poly(ethylene terephthalate) (PET) incorporating poly(4‐bromostyrene), poly(vinyl bromide), and poly(vinylidene bromide) has been studied using thermogravimetry, flammability limit evaluation, and hydrogen bromide (HBr) evolution techniques. The data obtained have been compared with limiting oxygen index (LOI) flammability data to elucidate flame retardation mechanisms. All the organo bromides studied (applied either via topical treatment or radiation grafting) released HBr on pyrolysis which is capable of inhibiting the gas phase combustion reactions. Condensed phase interactions were also detected which were capable of altering the gaseous pyrolysates. Thermal stability considerations suggest that, although the aliphatic bromides are excellent sources of HBr, they are not ideal flame retardants for PET.
Polyester molding compounds: Partial systems and related particulate composites
Authors: Danusso F. , Tieghi G. , Lestingi A. 
Published: April 2003

AbstractSeveral binary of ternary systems, consisting of an unsaturated polyester resin and one or two additives which are currently considered in formulating polyester molding compounds (such as BMC and SMC) were studied in relation to some of their relevant properties as a function of their composition. The additives were: MgO as a thickening agent; a thermoplastic polymer (PS or PVAc); and a fine CaCO3 particulate filler. Measured quantities were, depending on the system physical state (fluid or crosslinked): viscosity, linear shrinkage, flexural modulus and strength, and fracture toughness and energy, besides SEM morphological characterization. Quantitative relations could in several instances be expressed; in particular, the relation between strength and filler volume fraction was found to follow the linear equation of the simplest area reduction “random model”.
A kinetic and equilibrium model for nylon 6,6 polymerization
Authors: Steppan D. D. , Doherty M. F. , Malone M. F. 
Published: April 2003

AbstractA simple, activity‐based solution model is used to develop thermodynamically proper correlation forms for the description of the rate and equilibrium behavior of nonideal polyamidations. The approach is especially useful in systems for which limited equilibrium and kinetic data are available. This model is applied to the nylon 6,6 system. the resulting correlation is valid for water concentrations from 1 to 90 mol% and for temperatures from 200 to 265°C. The equilibrium correlation is a function of the water mole fraction and temperature. At a fixed temperature, there is a maximum in the apparent equilibrium constant at a water concentration of approximately 10 mol%. There is an apparent inversion in the sign of the heat of amidation, as well as a continuous change in the apparent rate of polymerization from second to third order in carboxyl concentration at low water content.
Thermal stability of copolymer acrylamide–maleic anhydride
Authors: Vîlcu Rodica , Bujor Ingrid Ionescu , Olteanu Mihaela , Demetrescu Ioana 
Published: April 2003

AbstractThe thermal degradation of copolymer acrylamide–maleic anhydride prepared in various solvents (benzene, dioxane, methylethyl ketone) and different monomer ratios was investigated. The techniques of thermogravimetry (TG and DTG) and differential scanning calorimetry (DSC) were used. The IR spectra of degraded copolymers are discussed.
Effects of polymer‐filler adhesion on the properties of polychloroprene elastomers filled with surface‐treated fillers
Authors: Lee Michael C. H. 
Published: April 2003

AbstractA new analytical method has been employed to determine values for the surface‐energy properties, such as the solid/vapor surface energy and the equilibrium work of adhesion, of several polychloroprene compositions filled with organosilane‐treated wollastonite fillers. The equilibrium work of adhesion, which represents the amount of energy stored in the interface formed between polymer and filler, has been used as a key material parameter to correlate changes in the mechanical and rheological properties of wollastonite‐filled polychloroprene compositions. Experimental results show that some properties such as tear strength, tensile modulus, shear viscosity, and compression set, which depend on polymer‐filler adhesion to varying degrees, increase as the equilibrium work of adhesion increases. On the other hand, properties such as tensile strength and ultimate elongation, which largely depend on the degree of mixing of filler particles and such defect structures as microvoids, decrease with the increase of the equilibrium work of adhesion. A power‐law relationship between the tensile modulus and the equilibrium work of adhesion has also been established. This relationship can be used for selecting organosilane‐treated fillers in order to achieve optimum properties.
A simple technique for measuring the refractive index of polymer latexes at various wavelengths
Authors: Devon Michael J. , Rudin Alfred 
Published: April 2003

AbstractThe refractive index of emulsions of polymers and copolymers may be estimated from absorbance readings with a UV‐visible spectrophotometer. Other information needed is the weight‐average particle diameter, from other techniques such as gradient disc centrifugation. A simple computer program matches the refractive index parameter so that calculated and experimental absorbances are equal at the given wavelength. The wavelength dependence of the polymer refractive index is readily obtained.
Influence of reagent residues and catalysts on formaldehyde release from DMDHEU‐treated cotton
Authors: Pasad Dilip M. , Beck Keith R. , Vail Sidney L. 
Published: April 2003

AbstractObservations and conclusions drawn from a model N‐methylol reactant system have been used to study formaldehyde release from cotton fabric treated with N,N′‐dimethylol‐4,5‐dihydroxy‐ethyleneurea (DMDHEU). Reagent residues produced by DMDHEU in the presence of sodium bisulfate or zinc nitrate were found to be more complex than those formed from the N‐methylolpyrrolidone (NMP) reactant system, and the exact nature of some of the residues from DMDHEU could not be established. Zinc nitrate produces higher fixation of DMDHEU on cotton as compared to sodium bisulfate and also reduces formaldehyde release. As is the case with the NMP system, the lower amount of formaldehyde release with zinc nitrate catalyst is believed to be at least partially due to the formation of a complex between the N‐methylol reactant, DMDHEU, and zinc nitrate. The COCell bonds in both finishes resist acid‐catalyzed cleavage but cleavage of the NC bonds in N‐methylol groups (to release formadehyde) in the presence of acid is greater for the DMDHEU system than for the NMP system. Results with the DMDHEU and NMP systems are similar, but because of the complex nature of the products formed in the DMDHEU system it is very difficult to correlated formaldehyde release with specific chemical structures of residues or reactants.