bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polymer reactors and molecular weight distribution. VIII. A method of interpreting skewed GPC chromatograms
Authors: Balke S. T. , Hamielec A. E. 
Published: April 2003

AbstractA new‐method of interpreting GPC chromatograms which accounts for skewing and symmetrical axial dispersion has been developed. General relationships for a symmetrical axial dispersion correction and for a skewing correction are derived.The method has been verified experimentally for unimodal chromatograms and linear calibration curves over a wide range of GPC operating conditions, polymer molecular weights and polydispersities. Measurements of h and skewing factors were obtained by a once‐through technique. The need for performing reverse flow experiments has been eliminated. Artificial oscillations in the corrected chromatogram due to step size (Method of Pierce‐Armonas), and to number of terms in a polynomial expansion (Method of Tung and Method of Smith) are eliminated.The method has yet to be evaluated for nonlinear calibration curves and multi‐modal distributions. However, suggestions for its application in these circumstances are presented.
Multiaxial impact measurements of polypropylenes
Authors: Fujioka Kazuyoshi 
Published: April 2003

AbstractA new puncture tester of the falling weight type for conducting impact tests has been developed. With this tester, impact energy can be measured by means of an accelerometer fixed in the falling weight, and strength by a compression type load cell placed under a pot clamping a sample. Puncture behaviors are traced on an oscilloscope.Results of puncture measurements of isotactic propylene homopolymers and copolymers with ethylene showd that impact behaviour depended noticeably upon temperature. Ethylene concentration, isotacticity and molecular weight of polypropylene resins were not more effective in sustaining impact resistance in the range of temperatures below the brittle point than in bringing down the brittle point itself. It was confirmed by means of tensile impact tests that energy to failure depended not upon yield strength but upon deformation in ductile rupture, whereas in the brittle rupture case energy to failure depended primarily on the strength of the material.Dynamic mechanical measurement was also carried out to secure the relationship between crystallinity and impact resistance.
The photo‐oxidation of polypropylene: Some effects of molecular order
Authors: Kato Y. , Carlsson D. J. , Wiles D. M. 
Published: April 2003

AbstractFractional crystallization was used to separate a commercial, predominatly isotactice, unstabilized polypropylene into fractions of relatively low and relatively high atacticity, but of similar molecular weight. IR spectroscopy was used to follow the photo‐oxidations of films formed from these fractions during irradiation in air with light of wavelengths greater than 3000 À. The major oxidation products included hydrogenbond hydroperoxides and carbonyl compounds. Films of constant tacticity, but varying morphology were prepared by quenching from the melt. No distinct correlation was found between sample photostability and morphology, as indicated by film density. Films of low atactic content were found to undergo faster photo‐oxidation than films of high atactic content, irradiated under identical conditions. This effect is believed to be due to the occurrence of a stereo‐dependent step (or steps) in the oxidative chain, and not due to differences in sample morphology. The possible nature of the stereo‐dependent steps is considered in terms of well‐established oxidative chain processes. The effects of polypropylene polymorphism on oxygen permeability are briefly considered.
Grafting of preformed polyethylene oxide on starch
Authors: Ezra Gabriel , Zilkha Albert 
Published: April 2003

AbstractPolymer‐polymer interaction was used for the preparation of graft polymers of polyethylene oxide on starch. Preformed polyethylene oxide having hydroxyl end groups was converted to the chloroformate derivative and reacted with starch alkoxide. Watersoluble graft polymers were obtained free of cross linking. The efficiency of the coupling process decreased with increasing the DPn of the polyethylene oxide.
Effect of crystalline structure on the trapped radical spectra of irradiated cellulose
Authors: Arthur Jett C. , Hinojosa Oscar , Tripp Verne W. 
Published: April 2003

AbstractThe effects of crystalline modification of cellulose and of water on the ESR spectra generated by the trapped free radicals in gamma‐irradiated celluloses were investigated for cotton cellulose I, II, III, and IV, partially decrystallized cotton cellulose, ballmilled cotton cellulose, hydrocelluloses of cellulose III and IV, and ramie. On irradiation of the celluloses, free radicals were formed on the cellulose molecule, probably following dehydrogenation or chain cleavage. The free radicals located within the less ordered or amorphous regions of the cellulose reacted readily with water and were terminated. The radicals located within the more ordered regions of the celluloses could be made accessible to reaction with water by the interaction of the celluloses with solvents which caused dimensional changes in the cellulosic structure. In the highly ordered regions of the celluloses, even after long periods of time in solvents which caused large dimensional changes in the cellulosic structure, the trapped free radicals were not terminated by reaction with solvent or water. The ESR spectra of the irradiated, dried celluloses were determined at −160°C, the single‐line spectra recorded had line widths of about 18‐24 gauss. On the absorption of water by the irradiated celluloses, the ESR spectra changed and were dependent on the crystalline structure of the irradiated celluloses. The effects of different arrangements of the irradiated celluloses, as shown by their trapped radical spectra, particularly after interaction with water, were discussed.
Difluorocarbene modification of polymer and fiber surfaces
Authors: Olsen Douglas A. , Osteraas A. Jean 
Published: April 2003

AbstractDifluorocarbene (difluoromethylene, :CF2) generated by the pyrolysis of sodium chlorodifluoroacetate has been shown to irreversibly modify the surfaces of polymers and fibers. The critical surface tension values of several polymers are shown to decrease with increasing exposure to difluorocarbene vapors and ultimately approach the critical surface tension values of partially fluorinated polyethylenes. The rate‐controlling step appears to be the diffusion of difluorocarbene from the precursor to the polymer substrate. The nature of the interaction between difluorocarbene and the polymer surface is unknown; however, the absence of infrared bands due to CF bonds in attenuated total reflection measurements tends to establish the mono‐molecular‐like character of the modified surface.
Studies on disulfide‐crosslinked nylon. I. Elastic disulfide‐crosslinked polycaprolactam fiber
Authors: Tonami Hiroaki , Miyauchi Shin'nosuke , Sakamoto Munenori 
Published: April 2003

AbstractElastic disulfide‐crosslinked polycaprolactams of different sulfur contents (0.4‐3.3%) were prepared by the reaction of N‐methoxymethyl polycaprolactam (D.S., 0.30) with different amounts of thiourea, the hydrolysis with excess potassium hydroxide, and the spinning into aqueous hydrogen peroxide.The fibers obtained exhibited high elongation at break (500‐300%), low initial modulus (13‐1 kg/mm2), and high elastic recovery. The initial modulus decreased with increased crosslinking. Heat‐treatment of the fibers at 140°C lowered the initial modulus remarkably. The effect of the crosslinking and the residual methoxymethyl substitution on the structure and the physical properties of the untreated and heat‐treated fibers is discussed.The residual methoxymethyl groups were removed completely from the fibers by hydrolysis with formic acid. The removal led to marked reduction in the elongation and much increase in the initial modulus.
Environmental stress relaxation studies of polymers: Effect of benzene series hydrocarbons on polyethylene
Authors: Nisizawa Mizuho 
Published: April 2003

AbstractThe method of stress relaxation has been used to study stress decay behavior in the system of polyethylene—benzene series hydrocarbons. The behavior of stress decay in polyethylene under benzene series hydrocarbons was observed and the respective activity forward stress decay of benzene series hydrocarbons was obtained.
The reaction of polypropylene with maleic anhydride
Authors: Minoura Yuji , Ueda Minoru , Mizunuma Susumu , Oba Mareo 
Published: April 2003

AbstractAn addition reaction of maleic anhydride with polypropylene takes place in the presence of radical reagents or sunlight. The initial rate of the reaction was proportional to the concentration of polypropylene and maleic anhydride, and one‐half power of the concentration of the radical reagents. The increase in the temperature from 80 to 120°C increased the rate of the reaction and di‐cumyl peroxide was effective as a radical reagent for this reaction.Ionic crosslinked rubber‐like polymers were obtained from the reaction of maleic polypropylene with some alkali metal compounds. They showed the characteristic absorption band due to COO⊖ in their infrared spectra.
Dynamic mechanical properties of polymers
Authors: Legrand D. G. , Erhardt P. F. 
Published: April 2003

AbstractA technique, employing samples in the form of tuning forks, to measure the mechanical properties of polymers is presented. Results for low density polyethylene, polypropylene, and polycarbonates are shown. A large transition is observed for polypropylene at approximately +10°C and a small transition at −100°C for the polycarbonates. Polycarbonate data has also been obtained from 20 to 150°C, at approximately 70 cps. Effects of time, temperature, and history are presented.
Tetrachlorinated rubber: The addition of carbon tetrachloride to 1,4‐polybutadiene
Authors: Rosin Hadassa , Asscher M. 
Published: April 2003

AbstractThe iron chloride‐catalyzed radical chain addition of carbon tetrachloride to 1,4‐polybutadiene has been studied. Transparent film forming nonflammable polymers are obtained which contain 50–55% chlorine. Cyclization appears to accompany the addition of carbon tetrachloride as an integral part of the radical reaction.
Studies on adhesion of allylic resin. I. Adhesion of diallylphthalate resin and dichromate‐treated copper foil
Authors: Nara Shigeo , Matsuyama Kentaro 
Published: April 2003

AbstractAn effective copper surface treatment for adhesive bonding of copper foil and diallylphthalate resin was investigated.It involves dipping the copper foil in the potassium dichromate‐sulfuric acid solution (K2Cr2O7:76 g/l, H2SO4:0.67 N) at 60°C for 5 min. The dichromate treated copper foil and glass based prepregs of diallylphthalate resin were laminated under the pressure of 38 kg/cm2 for 30 min at 145°C.Interface characteristics of the dichromate treated copper foil and diallylphthalate resin were examined.It was found that chromium is formed on the surfaces of the treated copper foil, and allyl groups in diallylphthalate molecule are oriented to the atoms, that is, the adhesive bonding is performed by the chemical affinity of chromium and allyl groups.The allyl group has a delocalized π‐electron system, and that its bonding to a transition metal as chromium is appropriate and justifiable by quantum chemical considerations.
Ionic graft copolymerization. VIII. Homopolymerization of β‐propiolactone by radical catalysts in the presence of electron acceptors and application to graft copolymerization
Authors: Shiota Tetsuya , Hayashi Koichiro , Okamura Seizo 
Published: April 2003

AbstractThe polymerization of β‐propiolactone (βPL) induced by radiation and by radical catalysts, the influences of radical inhibitors and electron acceptors on this polymerization, and graft copolymerization were studied. It was found that βPL was polymerized by benzoyl peroxide in the presence of electron acceptors such as maleic anhydride and acrylonitrile. This polymerization method was applied to graft copolymerization. The electron donative trunk polymer containing ether groups was heated with benzoyl peroxide or was irradiated by γ‐rays from Co60 in the presence of maleic anhydride as the electron acceptor. βPL was added subsequently to form the graft copolymer.
Properties of PVC. III. Influence of the way of processing on the properties of PVC samples
Authors: Maláč J. 
Published: April 2003

AbstractThe work shows PVC qualitative dependence under the conditions for the preparation of samples and some of their properties. The different ways of preparation influences the differences of residual stress and the free volume of samples, which is apparent even on properties, the measuring of which is not sufficiently precise, and therefore the differentiating ability is small (as, e.g., the notch impact strength).
Mechanical properties and transition temperatures of copolymers of N‐n‐alkylacrylamides and vinylidene chloride
Authors: Jordan Edmund F. , Riser George R. , Artymyshyn Bohdan , Parker Winfred E. , Pensabene John W. , Wrigley A. N. 
Published: April 2003

AbstractMechanical and solution properties, melting transitions, torsional stiffness temperatures, Tf, and selected modulus‐temperature curves are presented for copolymers of the N‐n‐alkylacrylamides with vinylidene chloride. Copolymers were prepared at 60°C across the range of compositions, using as comonomers N‐n‐butyl‐, octyl‐, dodecyl‐ and oleyl‐acrylamide, which have amorphous side‐chains, and N‐n‐octadecyl acrylamide and n‐octadecyl acrylate whose side‐chains are crystalline. The mechanical properties reflected the effect of the decline in backbone crystallinity and the simultaneous development of strong intermolecular interactions in the amorphous stage. Copolymers were stiff or showed brittle failure across the compositional range except when intermolecular forces were reduced (with n‐octadrcyl acrylate) and side‐chain crystallization eliminated (with N‐oleylacrylamide). These systems and the n‐dodecylacrylamide copolymers had yield strengths less than brittle strengths and substantial elongations. Backbone crystallinity was eliminated at about 15 mole % amide and side‐chain crystallinity vanished at less than 10 mole % of the amide in the N‐n‐octadecylacrylamide series. No depression in side‐chain melting point occurred with dilution by segments of vinylidene chloride. Over‐all decline in the flex‐temperature was the normal monotonic function of composition except that values increased in magnitude at high vinylidene chloride contents, the effect presumably being caused by the presence of crystallinity. An empirical equation was developed which permitted the calculation of Tf for any N‐n‐alkylacrylamide composition with any number of carbon atoms in the side‐chain, above 3.
Radiation‐induced copolymerization of maleimides and acenaphthylene in the solid state
Authors: Yamakita Hiromi , Hayakawa Kiyoshi 
Published: April 2003

AbstractThe γ‐ray‐induced polymerizations in the binary systems of maleimide‐acenaphthylene and N‐methylmaleimide‐acenaphthylene have been studied. The phase diagrams of the two systems show that an eutectic was formed in each system. It has been proven by the solvent extraction and the turbidimetric titration of obtained polymer that copolymer was formed in the eutectic of each system together with homopolymers. The fraction of total homopolymers in the maleimide‐acenaphthylene system was nearly the smallest in the monomer mixture of the eutectic composition. The composition of the copolymer, which was isolated by the extractions, was almost independent of the monomer composition. In order to elucidate these results, it was postulated that the copolymerization occurred at grain boundaries between the two components in the eutectic.
Reversible crosslinking in cellulose. I. Determination of mercaptan and disulfide in modified cotton
Authors: Sakamoto Munenori , Yamada Yoshio , Tonami Hiroaki 
Published: April 2003

AbstractMercaptan and disulfide contents of modified cotton fabrics could be determined by application of Leach's polarographic method for wool, with minor modification.It was found that mercaptocellulose prepared by the reaction of tosyl cellulose and potassium thiolacetate followed by alkaline hydrolysis contained considerable amounts of disulfided in addition to mercaptain. Iodometric titration of mercaptocellulose gave a higher value of mercaptan than that obtained by the polarographic method. The mercaptan and disulfide contents and methylene blue uptake of the iodine‐treated samples indicate that some of the mercaptan groups further undergo oxidation to acidic groups as a result of the iodine treatment.The spatial effect in the oxidation of mercapto groups in modified cotton is briefly discussed.
Effect of titanium compounds on thermooxidative properties of stabilized polypropylene
Authors: Kresta Jiří , Majer Josef 
Published: April 2003

AbstractThe effect of titanium compounds on thermooxidation stability of stabilized polypropylene was studied. It was found that the presence of titanium compounds shortens the induction period of PP oxidation. This phenomenon is brought about by the thermal reactions of titanium compounds with antioxidants which take place during polymer processing. The first step is the reaction of TiCl with OH groups of phenolic antioxidant, which gives rise to a colored titanate and HCl. Hydrogen chloride functions as a Friedel‐Crafts catalyst for degradation and dealkylation of phenolic antioxidants. The products of degradation have a very low stabilization efficiency. Hydrogen chloride acceptors suppress antioxidant degradation and increase the polymer stability even in the presence of small amounts of titanium compounds.
Structure‐property relationships in elastomer‐modified terpolymer systems
Authors: Hagerman Edward M. 
Published: April 2003

AbstractA number of terpolymers, incorporating as the elastomer phase polybutadiene, polyisoprene, poly‐2,3‐dimethylbutadiene, poly(butadiene‐co‐styrene), and poly(butadiene‐co‐2‐methyl‐5‐vinypyridine), were studied. Matrices were composed of poly(styrene‐co‐acrylonitrile) (SAN), poly(α‐methylstyrene‐co‐acrylonitrile), and poly(styrene‐co‐acenaphthylene). At constant elastomer content and elastomer molecular weight in systems employing a SAN matrix, Izod impact resistance was found to vary inversely with rising elastomer‐glass transition temperature. In systems of various matrix composition, using a polybutadiene elastomer, heat deflection temperatures were found to very directly and impact resistance inversely with rising matrix‐glass transition temperature. In acrylonitrile–butadiene–styrene (ABS), systems of constant matrix composition and elastomer content, varying the elastomer molecular weight from 0.6 to 2.6 × 105 resulted in increasing the Izod impact resistance from 0.67 to 12.8 ft‐lb/in. of notch.
Redox behavior in photochromic polymers of the thiazine series
Authors: Kamogawa Hiroyoshi 
Published: April 2003

AbstractThe photochromic redox behavior of the thiazine polymers prepared by the condensation reactions of the N‐hydroxymethylacrylamido components of vinyl polymers with four thiazine compounds, i.e., thionine and asym‐dimethyl‐, trimethyl‐, and mono‐methylthionine chloride, in combination with various electron‐donating components, including hydroxyl, amino, and sulfhydryl groups and ferrous ion, were investigated.The reversible color fading (at ca. 600 mμ) of the thiazine polymers under illumination in the solid state was found to be largely dependent upon the moisture content in the polymer. This, together with other evidence, suggests that water molecules adsorbed on the active groups in the polymer also participate in the reduction of the thiazine components. Polyvinyl alcohol, cellulose, and enzymes such as papain, when incorporated in the photochromic compositions, induce remarkable improvements of the photochromism, in both the sensitivity to light and the rate of color recovery in dark; the incorporation of the ferrous–ferric ion system into the polymers in the form of acrylates also improves photochromism remarkably, especially the rate of recovery.
Durability of bimetallic‐adhesive laminate with ethylene–acid copolymer adhesives
Authors: Wargotz B. 
Published: April 2003

AbstractA broadband multicoaxial cable has been developed, based upon the use of ethylene copolymer thermoplastic adhesives to bond tin‐plated steel to copper. The characteristics of the adhesive and the integrity of the bond formed between the dissimilar metals were of prime interest. The copolymers of ethylene examined as adhesives were ethylene–acrylic acid (EAA) and ethylene–methacrylic acid (EMAA). The influence of high humidity on the durability of bimetallic laminates of copper or aluminum with tin‐plated steel and ethylene–acid copolymer adhesives has been studied. Infrared spectrometric and differential thermal analysis data had shown that a contributing cause to failure of bonds between EAA copolymers and copper is the solubilization of an underlying weak copper oxide layer under condition of the test. Electrolytic chromate‐treated copper and immersion chromate‐treated aluminum bonded to degreased tin‐plated steel resulted in joints having comparable durability under stress and humid environments. These results reflect the durability of tin–tin bonded specimens. These materials engineering studies have shown that ethylene–acid copolymer adhesive, properly used and stabilized, can be employed with confidence in adhesive joints.
Studies on the mechanism of fine‐structure development during industrial cellulose yarn production
Authors: Bromley K. , Aitken R. 
Published: April 2003

AbstractA study has been made of the diffusion of zinc ions into alkaline solutions of sodium cellulose xanthate (viscose) when these are extruded into acidified salt solutions (spin‐bath). Under these conditions, which exist during the manufacture of regenerated cellulose industrial yarns, the zinc ions are diffusing into a continuously coagulating gel structure from which water is exuded as the structure is developed. It has been shown that the presence of certain additives (modifiers) in the viscose can slow down the diffusion of both zinc and hydrogen ions, thus retarding the coagulation and neutralization of the viscose. In the initial stages of coagulation, before the neutralization point is reached, the modifiers reduce the rapid filament shrinkage and pressure rise within the filament which would otherwise be caused by the presence of zinc ions in the spinbath. The mode of action of the modifiers is discussed in the light of current theories. A hypothesis is put forward that the modifiers act by preventing the initial rapid shrinking action of the outer cuticle of the filament. This permits the production of the desired fine structure inside the filament during a slower steady shrinkage which leads to a round cross‐sectioned filament of good mechanical properties.
Base‐hydrolyzed starch‐polyacrylonitrile (S‐PAN) graft copolymer. S‐PAN‐1:1, PAN M.W. 794,000
Authors: Gugliemelli L. A. , Weaver M. O. , Russell C. R. , Rist C. E. 
Published: April 2003

AbstractStarch‐polyacrylonitrile (S‐PAN) graft copolymer consisting of one part starch and one part polyacrylonitrile (M. W. 794,000) was hydrolyzed with aqueous KOH at 80 and 100°C to polyelectrolytes containing carboxyl and amide functionality but void of infrared‐detectable amounts of nitrile. Viscosities of potassium salts of the polyelectrolytes in water were pH dependent with peak viscosities at 8.5. These dispersions were characterized by unusually high viscosities, 15,000 to 26,500 cp at 1% concentration, and by the ability to retain significant viscosities, 300 to 950 cp, upon dilution to 0.03% concentrations. A 1% dispersion of hydrolyzed S‐PAN had a viscosity of 5,000 cp in the presence of 8% KCl; however, the depressing effect of added salts on viscosity of aqueous dispersions of hydrolyzed S‐PAN increases as the valence of the cation increases.