bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quick identification and analysis of plasticizers in PVC by programmed‐temperature gas chromatography using the best stationary phases
Authors: Messadi Djelloul , Vergnaud Jean‐Maurice 
Published: April 2003

AbstractA quick and safe identification method is shown for plasticizers in PVC using programmed‐temperature gas chromatography. Plasticizers were identified by their retention index values measured by using normal paraffins. Several stationary phases with quite different polarity are proposed: with silicone polymers (SE 30, OV 17, and QF 1) and a porous polymer such as Tenax. Operational conditions were optimized. The initial column temperatures was chosen at a low value of 100°C with the first three phases and 180°C for the fourth. The best rate of temperature increase with time seemed to be 10°C/min. The calculation method for retention values (temperature, time, indices) was chosen just because it needed no approximation. Thermodynamic values for the solution of plasticizers were measured by using isothermal chromatography with all the stationary phases. Our method allows the analyst to operational conditions (solvent, percent, temperature) for chromatography, to solve his own problem by making use of a pocket computer. Quantitative analysis of plasticizers was obtained with good accuracy after a previous extraction and the addition of normal paraffin as internal standard.
Phenolic and tannin‐based adhesive resins by reactions of coordinated metal ligands. I. Phenolic chelates
Authors: Pizzi A. 
Published: April 2003

AbstractBivalent and trivalent metallic ions, respectively, accelerate and inhibit the reaction of phenols with formaldehyde. The catalytic effect of these metallic ions is equivalent, though more marked, to that of hydrogen ions, and it is due to their stronger charge. Metallic ions/phenols/formaldehyde complexes are formed. The stability of these complexes and mainly their rate of metal exchange in solution are the determining factors in the accelerating or retarding action. Identified stable chromium (III)–resorcinol–formaldehyde and chromium (III)–phenol–formaldehyde complexes have slow rates of metal exchange and inhibit the resorcinol–formaldehyde and phenol–formaldehyde reactions. The opposite is valid for lead (II), zinc (II), and other bivalent metallic ions. A scale showing the order of the accelerating effect of a series of metallic ions is given. The presence of polymeric complexes has also been observed.
Humid aging of plastics: Effect of molecular weight on mechanical properties and fracture morphology of polycarbonate
Authors: Gardner Robert J. , Martin John R. 
Published: April 2003

AbstractPolycarbonate tensile bars were aged up to 18 months at 0%, 75%, and 100% relative humidity and temperatures of 65–93°C. In the humid aged samples hydrolysis caused progressive reductions in molecular weight. Below a critical molecular weight (Mw = 33,800, Mn = 14,300) tensile strength dropped off rapidly. A transition from ductile to brittle failure was also observed at that point. Extrapolations indicate that the ductile–brittle transition at 38°C will be reached after 5 years at 100% relative humidity for the polycarbonate studied. Elongation was affected even in the early stages of hydrolysis. This suggests that whenever the degradation mechanism is a molecular weight reduction, toughness will be affected before the strength properties are lost. Mechanical properties are affected by annealing and antiplasticization which reduce localized stresses and increase short‐range order. The brittle fracture surfaces of polycarbonate consist of four distinct regions. The size of the regions and the prominence of the features changed as the molecular weight decreased.
Effects of phosphorus‐containing flame retardants on pyrolysis of cotton cellulose
Authors: Franklin W. E. , Rowland S. P. 
Published: April 2003

AbstractUnmodified cotton and cottons finished with high levels of seven different phosphorus‐containing flame retardants were pyrolyzed in a temperature‐programmed solid probe of a mass spectrometer, and mass spectra were recorded continuously throughout the pyrolyses. The spectra at the maximum rates of volatiles evolution during the pyrolyses were analyzed to determine relative amounts of water, carbon monoxide, carbon dioxide, furfural, furyl hydroxymethyl ketone, hydroxymethylfurfural, levoglucosan, and 1,6‐anhydro‐β‐glucofuranose. These volatile materials accounted for 64% to 90% of the total ionization in the spectra. The flame retardants increased the fractions of nonfuel volatiles (water and carbon dioxide) and decreased those of anhydroglucoses, but had less effect on the carbon monoxide and furan derivatives. The flame retardant fabrics differed greatly in the fractions of anhydroglucoses (from 1% to 23%) and water (from 19% to 57%) in their pyrolysis products. These results indicate that mechanisms of flame retardant action differ among phosphorus‐containing finishes.
Thermal oxidative studies of poly(hexafluoropropene oxide) fluids
Authors: Paciorek K. J. L. , Kratzer R. H. , Kaufman J. , Nakahara J. H. 
Published: April 2003

AbstractElucidation of mechanisms operative in thermal oxidative degradation of hexafluoropropene oxide derived polyethers and the effect of metals on these processes are reported. Thermal oxidative instability of a commercial fluid, at moderate temperatures (550°F), was found to be due to the presence of ∼3% of thermooxidatively unstable chains believed to be hydrogen terminated; treatment at 650°F in oxygen volatilized these chains by unzipping. The resultant fluid was unaffected by oxygen at 650°F and by M‐50 and Ti(4Al, 4Mn) alloys at 600°F in oxidizing atmospheres. M‐50 alloy catalyzed the degradation of the hydrogen‐terminated chains below and at 600°F, but after completion of this process did not affect the remainder of the fluid at these temperatures. At 650°F a chain scission process promoted by the metals constituting the alloy, or their oxides or fluorides, came into play. Ti(4Al, 4Mn) alloy in the presence of CF3COF and COF2 species, formed via decomposition of the hydrogen‐terminated chains, degraded poly(hexafluoropropene oxide) fluids at 550°F by chain scissions.
Impact strength of thick‐interlayer composites
Authors: Peiffer Dennis G. 
Published: April 2003

AbstractThe impact strength of a thicker interlayer fiber filled composite material is evaluated as a function of both interlayer thickness and glass transition temperatures (Tg). The results confirm that for maximum strength, an optimum interlayer thickness is required. It is shown that this result is a function of the interlayer's Tg. Comparison with studies on other rubber reinforced systems are noted.
Interfacial properties of polyelectrolyte‐cellulose systems. IV. Electrokinetic properties of carboxymethylcellulose fibers with adsorbed multilayers of cationic polyelectrolyte
Authors: Onabe Fumihiko 
Published: April 2003

AbstractZeta potential measurements by the streaming current method were performed on carboxymethylcellulose (CMC) with and without irreversibly adsorbed multilayers of cationic polyelectrolyte. Factors affecting the electrokinetic properties such as the amount of adsorbed polymer, polymer molecular weights (Mn 50,000 and 200,000), ionic strength (10−5 ∼ 10−2M KCl), and pH of the streaming medium (KCl solutions) were examined. The negative zeta potential of CMC decreased to the point of monolayer formation and increased from that point to the saturated multilayer formation. The polarity of the zeta potential was negative throughout every adsorption stage. The negative zeta potential increase was attributed to: (a) binding of anions (Cl− and OH−) to the outermost layer of the multilayer from KCl solutions and (b) change in chemical potentials of counterions in a diffuse double layer due to expansion of the double layer in the presence of the adsorbed multilayer on CMC. The results suggest that the carboxyl groups under the monolayer are undetectable electrokinetically; however, the negative charge, due to unneutralized carboxyl groups under the monolayer, appears to cause further adsorption forming a saturated multilayer. When the effect of unneutralized carboxyls of CMC are shielded at higher levels of adsorption, the outermost layer of the multilayer becomes a potential‐determining layer.
Radiation‐induced polymerization of ethylene in pilot plant. III. Heavy‐phase recycling process
Authors: Takehisa Masaaki , Watanabe Hiromasa , Kurihara Hirondo , Yamaguchi Kouichi , Nakajima Hayato , Yagi Toshiaki , Watanabe Terutaka , Sugo Takanobu , Suwa Takeshi , Maruyama Shinsaku , Kodama Atsuro , Shimada Takeo , Maruyama Yoshio , Tohei Masamichi , Wada Takeshi , Machi Sueo 
Published: April 2003

AbstractRadiation‐induced polymerization of ethylene using aqueous tert‐butyl alcohol as medium was carried out in a large‐scale pilot plant with a 50‐liter central source‐type reactor at a pressure of 105 to 395 kg/cm2, temperature of 30° to 80°C, mean dose rate of 4.5 × 104 to 1.9 × 105 rads/hr, ethylene feed rate of 5.5 to 23.5 kg/hr, and medium feed rate of 21 to 102 l./hr. The space–time yield and molecular weight of the polymer were in the range of 4.7 to 16.8 g/l.‐hr and 1.3 × 104 to 8.9 × 104, respectively. The space–time yield and molecular weight increased with mean residence time at 30°C, whereas at 80°C they became almost independent of the time. The space–time yield increased with pressure and dose rate, slightly decreased with temperature, and was maximum at ethylene molar fraction of 0.5. The polymer molecular weight increased with pressure and ethylene molar fraction, and decreased with dose rate and temperature. The total amount of deposited polymer on the reactor wall, source case wall, and scraping blades was usually less than 1 kg, which was negligibly small for the analysis of polymerization. Continuous discharge of the polymer slurry and production of fine‐powder polyethylene were successfully carried out. In the central source‐type reactor, a dose rate of 1.9 × 105 rads/hr was obtained with a 60Co source of ca. 12 kCi.
Refractive index increments of polyethylene
Authors: Horská Jitka , Stejskal Jaroslav , Kratochvíl Pavel 
Published: April 2003

AbstractThe refractive index increments of linear and branched polyethylene were determined for several solvents and various wavelengths (403, 436, 546, and 633 nm), mainly at 135°C. Differences were observed between values for linear and branched samples. Data obtained in this investigation are compared with the reported ones.
Stabilization of poly(vinyl chloride). IV. Color changes on heating poly(vinyl chloride)–dye systems
Authors: Iida Takeo , Gotō Kunio 
Published: April 2003

AbstractThe stabilization of poly(vinyl chloride) (PVC) involving complementary colors has been previously reported. Obliterating polyene color with various dyes containing complementary colors with the polyene color is studied on the basis of colorimetry. The changes in the color of heated PVC containing Thren Blue IRN, Ceres Blue GN, Oplas Violet 730, Macro‐Lex Violet 3R, Macro‐Lex Green 5B, or Macro‐Lex Red 5B were investigated using a differential colorimeter. When the PVCs containing various dyes were heated, the discoloration from the color of each dye to the color mixture of each dye and polyene color was observed with increased heating times for all systems. In particular, an achromatic color has been observed, during the heat treatments, in PVC containing blue dyes such as Thren Blue IRN or Ceres Blue GN, which set up complementary color relationship with the polyene color. Thus the color of polyenes, which appears with advancing dehydrochlorination of PVC, is masked by the blue dyes. It is also apparent that the obliteration of polyene color does not depend on the chemical influences of the dyes added, but by color mixing of polyenes and the dyes. Cool‐color dyes markedly slow down the appearance of polyene colors.
Dielectric behavior of the constituents of the natural resin shellac
Authors: Goswami Dipendra Nath 
Published: April 2003

AbstractThe dielectric relaxation data of the constituents of natural resin shellac have been analyzed by the Cole–Cole method at temperatures between 10° and 90°C in the frequency range of 50 Hz to 500 kHz. The functional groups present in hard and soft lac appeared to be responsible for the dielectric properties exhibited by shellac below and above its glass transition and melting temperature, respectively. A combination of 70% hard lac and 30% soft lac was found to exhibit the dielectric properties of shellac satisfactorily.
Water permeation of polymer films. II. Dual‐mode absorption in teflon FEP
Authors: Sacher E. , Susko J. R. 
Published: April 2003

AbstractDuPont Teflon FEP has been shown to permeate water vapor through a dual‐mode process: adsorption followed by permeation. A model is proposed for this process based on the interactions of condensible gas molecules with themselves and with the polymer surface. This model appears to have general applicability.
Experimental study of the relationship of processing to the morphology in blends of SBR and cis‐polybutadiene with carbon black
Authors: Lee Biing‐Lin , Singleton Chloe 
Published: April 2003

AbstractThe morphology of carbon‐black‐loaded styrene–butadiene rubber (SBR)/cis‐1,4‐polybutadiene (BR) blends is characterized as a function of mixing energy input. The blends consist of an 80:20 weight ratio of SBR and BR with the incorporation of 20 phr carbon black via three different schemes. These schemes are: (1) free mixing of the three components, (2) mixing of BR–black masterbatch with SBR, and (3) mixing of SBR–black masterbatch with BR. Differential scanning calorimetry (DSC) and electron microscopy (EM) results indicate that the domain morphology is strongly affected by the manner in which the carbon black is introduced into these blends. Some of the features of the blends are as follows: (1) BR, which is the minor rubber component, is always the dispersed phase, and its domain size decreases with increasing energy input during mixing. (2) In the black–rubber masterbatch mixing, the black always stays in the original rubber phase throughout the mixing process. No significant migration of carbon black from one rubber phase to the other is observed. (3) In the free mixing process, the carbon black agglomerates initially line up along the SBR–BR interfaces, and later disperse throughout the SBR matrix with increased mixing. However, the DSC results suggest that the amount of carbon‐black‐free BR is decreasing with increased mixing. This would occur if there is created a carbon‐black‐loaded SBR–BR diffuse interphase. A model is developed to interpret these findings.
Preparation of higher aliphatic acid esters of wood in an N2O4–DMF cellulose solvent medium
Authors: Shiraishi Nobuo , Matsunaga Tadayo , Yokota Tokuo , Hayashi Yoshiyuki 
Published: April 2003

AbstractEsterification of wood meal with a series of aliphatic acid anhydrides and acid chlorides in a nonaqueous cellulose solvent, an N2O4–DMF solvent, has been studied. The N2O4–DMF–pyridine solution used as the reaction medium plays a role in destroying the molecular order of the cellulose within the wood, enabling the cellulose to be uniformly substituted by acyl groups along its chain. These uniformly distributed blocking groups result in the permanent decrystallization of the wood. The acyl blocking groups are best achieved by esterification using acid chlorides in the nonaqueous solvent. Acid chlorides, from caproyl to stearoyl chloride, were found to be much more effective as acylating agents than acid anhydrides, from propionic to caproic anhydride. Although no difference in reactivity can be recognized among the acid chlorides, the reactivity decreases with increase in the number of carbon atoms in the acyl group among the acid anhydrides.
Thermal softening and melting of esterified wood prepared in an N2O4–DMF cellulose solvent medium
Authors: Shiraishi Nobuo , Matsunaga Tadayo , Yokota Tokuo 
Published: April 2003

AbstractThe thermal softening and melting of a series of esterified wood samples, whose preparation has previously been described,4 have been studied by measuring the deformation of the samples under constant load at a constant heating rate. The introduction of acyl groups into wood including part of the original crystal structure in cellulose makes the modified wood meal conspicuously thermoplastic. While untreated dry wood shows a thermal softening point (Ts) of ca. 260°C, esterified wood meal samples with acyl groups larger than caproyl have a Ts of around 100°C or less, and appeared to melt over the temperature range of 220° to 250°C. In this case, the melting occurs even with wood meal samples esterified with appropriate acid chlorides in an N2O4–DMF–pyridine medium only for 30 min at room temperature. This might be the first finding that wood meal is converted, as a whole, into a thermoplastic material which can melt without any accompanying detectable degradation.
Effects of moisture and stoichiometry on the dynamic mechanical properties of a high‐performance structural epoxy
Authors: Keenan Joseph D. , Seferis James C. , Quinlivan John T. 
Published: April 2003

AbstractDynamic mechanical measurements have been made on a 4,4′‐diaminodiphenyl sulfone‐cured tetraglycidyl 4,4′‐diaminodiphenylmethane epoxy (TGDDM‐DDS). There are basically three transitions on the mechanical spectra that have been identified, and the effects of moisture uptake and amount of DDS on these transitions were examined. The dynamic mechanical behavior of the same epoxy with 60% carbon fiber loading was also studied, providing further elucidation on the nature of the transitions observed with this system.
Effect of postdrawing on the permeability of gases in blown polyethylene film
Authors: Paulos James P. , Thomas Edwin L. 
Published: April 2003

AbstractThe effect of orientation on the structure and transport properties of high‐density polyethylene film has been studied. Microstructure was characterized using small‐angle light scattering, birefringence, and wide‐angle x‐ray scattering. Water vapor and oxygen transmission rates were determined as a function of film draw ratio. The object of the present work is to correlate the effects of postprocessing conditions on the transport properties and morphology of linear polyethylene. High‐density spherulitic polyethylene films were produced by blown film extrusion and subsequently oriented by longitudinal stretching in a postoperation. Various degrees of orientation were imparted to the films, with percent crystallinity, sample orientation and transport properties measured as a function of draw ratio. For the postoriented films, results indicate there was no significant change in percent crystallinity with increasing draw ratio although water vapor and oxygen permeability decreased substantially. This is attributed to the increased orientation of the crystalline and amorphous regions and rod‐like and microfibril structure formation brought about by the drawing process. Lower processing temperatures result in increased orientation which improves the vapor barrier properties.
Surface modification of polyethylene by radiation‐induced grafting for adhesive bonding. IV Improvement in wet peel strength
Authors: Yamakawa Shinzo , Yamamoto Fumio 
Published: April 2003

AbstractAdhesive joints of hydrolyzed methyl acrylate grafts, bonded with epoxy adhesives, yield extremely high peel strength (adherend failure) in dry conditions. However, when the joints are exposed to humid environments, the peel strenght rapidly decreases with exposure time and then reaches a constant value (wet peel strength). Since the locus of failure changes from the adherend to the homopolymer layer with decreasing peel strength, the decrease is due to a decrease in mechanical strength of the homopolymer layer itself, which results from its swelling by water absorption. Many attempts to reduce the swelling of the homopolymer layer or to strengthen the swollen homopolymer layer were unsuccessful except (1) priming with epoxy solutions consisting of a base epoxy resin and organic solvents which can dissolve not only epoxy resins but also hydrolyzed poly(methyl acrylate) and (2) partial etching of the homopolymer layer by photo‐oxidative degradation. All the results on the improvement in wet peel strength can be explained in terms of the penetration of epoxy resins into the homopolymer layer and subsequent curing of the penetrated epoxy resin.
Grafting vinyl monomers onto wool fibers. V. Graft copolymerization of methyl methacrylate onto wool using peroxydiphosphate as initiator
Authors: Nayak Padma L. , Lenka Subasini , Mishra Munmaya K. 
Published: April 2003

AbstractGraft copolymerization of methyl methacrylate onto wool was investigated in aqueous solution using potassium peroxydiphosphate as initiator. The rate of grafting was determined by varying monomer, peroxydiphosphate ion, temperature, solvent, and nature of wool. The graft yield increases with increase in monomer concentration. The graft yield increases significantly by increasing peroxydiphosphate ion up to 80 × 10−4mole/l.; with further increase of peroxydiphosphate ion the graft yield decreases. The rate of grafting increases with increase in temperature. The effect of acid‐and water‐soluble solvents on the rate of grafting was investigated and a suitable rate expression has been derived.
The initiation of in situ polymerization of vinyl monomers in polyester by glow discharge
Authors: Moshonov Aharon , Avny Yair 
Published: April 2003

AbstractGlow discharge initiation of in situ polymerization of acrylic acid and other vinyl monomers incorporated in PET films was investigatigated. The influence of glow discharge conditions such as the gas used, plasma power, discharge current, and plasma treatment time on polymerization yield was determined. Though glow discharge effects are limited to the film surface, in situ polymerization of the vinyl monomers took place and the vinyl polymer could be found all through the film cross section. At short plasma treatment time only surface modification took place, while at longer treatment time bulk modification occurred, too. Good polymerization yields were obtained. Gel effect behavior was observed. Mechanical properties of the modified PET film were not changed, while the contact angle with water improved when polar vinyl monomers were used.
The formation of volatile pyrolyzates form poly(vinyl chloride)
Authors: Lattimer Robert P. , Kroenke William J. 
Published: April 2003

AbstractThe formation of volatile pyrolyzates in poly(vinyl chloride) has been studied by pyrolysis–gas chromatography–mass spectroscopy. Isotopic distributions of pyrolyzates from experiments with perdeutero‐PVC show that pure conjugated aromatic pyrolyzates (e.g., benzene, styrene, naphalene, biphenyl, anthracene) are formed mostly via intramolecular cyclization. Mixed aromatic‐alphatic pyrolyzates (e.g., toluene, indene, methylnaphthalene) are formed at least partially via intermolecular (crosslinking and/or hydrogen transfer) mechanisms. Direct scission of the PVC chain to form chlorine‐containing pyrolyzates is a very minor degradation pathway. Most chlorine‐containing “pyrolyzates” from PVC are due to secondary reactions of HCl with the environment or with non‐PVC compounding ingredients. No evidence was found for oxygen‐containing pyrolyzates derived from the PVC backbone under conditions of nonflaming pyrolysis in air.