bluuebunny/crossref_metadata_2025_split huggingface dataset:
The preparation and properties of chelates of transition metal ions with the homopolymer and copolymers of p‐vinylbenzoylacetone
Authors: Chapin Earl C. , Twohig Elizabeth Festa , Keys Loren D. , Gorski Kathleen M. 
Published: April 2003

Abstractp‐Vinylbenzoylacetone (VBA) was prepared by the condensation of p‐vinylacetophenone and ethyl acetate. This monomer was homopolymerized and copolymerized with acrylamide or maleic anhydride to produce polymers which would chelate substantial amounts of transition metal ions such as Cu2+, Ni2+, Co2+, Eu3+, and VO2+. In the case of the Cu2+ and Ni2+ chelates, about 80–90% of the metal ion could be eluted by dilute mineral acids. The resulting eluted products apparently have a somewhat porous structure because they are capable of rechelating these ions from water solution, even though the solid homopolymer which had not been chelated and eluted is too hydrophobic to chelate very much metal ion from water solution. The eluted Cu2+ chelate readily reaccepted Cu2+ ions from water solution and discriminated against Ni2+ almost completely. However, the eluted Ni2+ chelate would reaccept both Cu2+ and Ni2+ ions, but exhibited a strong preference for Cu2+ ions in competitive batch experiments. The VO2+ chelate was an effective heterogeneous phase catalyst for the epoxidation of allyl alcohols such as geraniol with tert‐butylhyroperoxide. The chelate was stable under these oxidative conditions and could be recovered unchanged and reused.
Behavior of chemically modified cellulose towards dyeing. XIV. Behavior of cotton and crosslinked cottons before and after mercerization towards some reactive dyestuffs
Authors: El‐Aref A. T. , Allam E. , Abou‐Amer M. , El‐Hilw Z. , Hebeish A. 
Published: April 2003

AbstractCotton fabric was crosslinked with DMDEU by applying the Form D‐Process and Form W‐Process. The cotton and crosslinked cotton were then treated with caustic soda solution of mercerizing strength. The ability of cotton and crosslinked cottons to dyeing with two reactive dyes, viz. Procion Blue MRB and Procion Red HB was examined. It was found that crosslinking reduces significantly the amenability of cotton to reactive dyes particularly when the Form D‐Process was applied. Mercerization enhances dyeability of all substrates, but the enhancement was much greater in the case of noncrosslinked cotton. Based on dyeing and other properties such as tensile strength, elongation at break, and crease recovery, it was shown that crosslinking decreases considerably the affinity of cotton to caustic soda solution. It was further anticipated that different color designs with different patterns and properties can be conferred on a given cotton fabric by making use of local crosslinking and/or mercerizing followed by dyeing.
Investigations of stabilizing additives. IV. PEPQ as a primary radical scavenger
Authors: Williams J. L. , Williams E. E. , Dunn T. S. 
Published: April 2003

AbstractStudies of PEPQ in a model antioxidant activity system have demonstrated that this material behaves not only as a hydroperoxide decomposer but as a primary radical scavenger. The temperature dependence of the antioxidant activity also indicates the PEPQ is more effective at higher temperatures than at ambient conditions. The relationship between the model antioxidant activity system and melt stability measurements in polypropylene is in good agreement and implies that PEPQ is an effective melt stabilizer even in the absence of conventional phenolic stabilizers such as BHT.
Studies of polymer electrets. II. Factors governing the stabilities of homoelectrets obtained from polystyrene and its derivatives
Authors: Mishra Anu 
Published: April 2003

AbstractPolystyrene and its various alkyl and halo derivatives have been studied as homoelectrets and their stabilities under different environmental conditions determined. The stabilities of the homoelectrets prepared from these polymers depended on their volume resistivities, glass transition temperatures, and interactions with electron‐acceptor impurities. Excellent stabilities were exhibited by the homoelectrets prepared from polystyrene, poly(vinyltoluene), poly(chlorostyrene), and poly(t‐butylstyrene). It is postulated that the charged particles are trapped by the π‐orbitals of the phenyl rings present in these polymers and that they are adversely affected by the presence of electron‐acceptor compounds that generally from charge‐transfer complexes with the phenyl groups.
Optimization of spinning, drawing, and annealing conditions in the production of highly oriented fibers from the polycaprolactam/3.7% LiCl system
Authors: Acierno D. , Zenna S. Castrovinci , La Mantia F. P. 
Published: April 2003

AbstractA polycaprolactam/3.7% w/w LiCl system, obtained by anionic polymerization of caprolactam directly in the presence of salt, has been employed for the production of highly oriented fibers. More particularly, an optimization of spinning, drawing, and annealing conditions has been performed, finally obtaining fibers which shows very satisfactory mechanical results. Namely, average moduli values up to 12 GPa and strength values up to 1 GPa when fracture is far from clamps, have been observed.
Ozonization of amides
Authors: Imamura Sei‐Ichiro , Nishii Koji , Teranishi Hiroshi 
Published: April 2003

AbstractOzonization of various amides was carried out as a model reaction for the degradation of polyamides with ozone. N‐alkylamides and N,N‐dialkylamides were found to be reactive compared with those amides which have no alkyl group on the nitrogen atom, and it was suggested that ozone attacks preferentially N‐methylene or N‐methyl group of amides in the first step of ozonization.
A study of sulfur bridges in filled natural rubber vulcanizates by pyrolysis gas chromatography with flame‐photometric detection
Authors: Andersson Eva M. , Ericsson Inger , Trojer Lena 
Published: April 2003

AbstractNatural rubber vulcanizates of two formulations, with sulfur/N‐cyclohexyl‐2‐benzothiazolesulfenamide (CBS) and tetramethylthiuram disulfide (TMTD), respectively, were analyzed by pyrolysis gas chromatography. A sulfur‐selective flame‐photometric detector was utilized. The main pyrolysis products were identified as CS2 and some thiophenes. The yields of the pyrolysis products from the two types of rubber were very different. The yields also varied with the curing time of the rubbers.
Structure–property relationships in PVC compression moldings
Authors: Gilbert M. , Ansari K. E. 
Published: April 2003

AbstractCompression moldings were produced from two rigid PVC compounds at a range of temperatures. The tensile and impact properties of these moldings depended primarily on the level of particle fusion as assessed by extrusion rheometry. Properties were not related to the level of primary crystallization measured by X‐ray diffraction, but the particle fusion process appears to be at least partly due to recrystallization. Fusion occurred more readily in the mass PVC compound than in the suspension PVC compound. Annealing the sheet produced at 200°C caused changes in crystallinity which resulted in small property changes. The maximum annealing effect occurred at 110°C.
Effect of a synthetic tanning agent on the diffusin properties of an acid dye in nylon 6
Authors: Guthrie J. 
Published: April 2003

AbstractThe diffusion coefficients of an acid dye in nylon 6 polymer hav been measured using two different techniques, one based on the rate at which the fiber absorbs the dyestuff and the other employing the rate of transport of dye through a nylon film. Both of these methods yield diffusion coefficients of similar magnitude. The effect of a synthetic tanning treatment on the diffusion coefficients has been studied and it has been shown that a significant reduction in the diffusion coefficient is only obtained from data based on adsorption measurements. It is concluded that the decrease of rate of dye uptake caused by the presence of the syntan is due mainly to the prevention of initial dye adsorption rather than electrical repulsion or steric effects proposed in earlier studies. These results also highlight the dangers in using adsorption studies as a method for determining diffusion parameters.
Photopolymerization of acrylonitrile sensitized with a combination of aromatic ketone and amine
Authors: Kubota Hitoshi , Ogiwara Yoshitaka 
Published: April 2003

AbstractEffect of amines on photopolymerization of acrylonitrile sensitized with various sensitizers was investigated in N, N‐dimethylformamide at 30°C. Photopolymerizations sensitized with aromatic ketones such as benzophenone (BP), fluorenone (Fl), acetophenone, and Michler's ketone were noticed to be activated by triethylamine (TEA). Diethylamine, tri‐n‐butylamine, di‐n‐butylamine, and n‐butylamine besides TEA also proved to be effective for the system sensitized with BP or Fl. On the other hand, TEA indicated a negative effect for systems sensitized with α,α′‐azobisisobutylonitrile (AIBN), benzoyl peroxide (BPO), benzoin, and 2‐tert‐butylanthraquinone. Characteristics of the BP—and Fl—amine‐sensitized systems were compared with the systems sensitized with AIBN, BPO, and benzoin with respect to kinetics. Contrary to the latter polymerizations following the general kinetics, including the termination of growing chains by mutual deactivation, the former polymerizations were characterized by an elevated susceptibility of the primary radical termination.
Thioetherglycidyl resins. III. Products of condensation of bis(4‐mercaptophenyl)ether and bis(4‐mercaptophenyl)methane with epichlorohydrin
Authors: Charms Władysław 
Published: April 2003

AbstractThioetherglycidyl resins produced by condensation of bis(4‐mercaptophenyl)ether and bis(4‐mercaptophenyl) methane with epichlorohydrin were obtained by heterophase alkaline condensation. To define the optimal conditions of condensation, the following factors that influence the process were studied: the kind of organic phase and the mole ratios of epichlorohydrin:mercaptan, alcohol:mercaptan, and alkaline hydroxide:mercaptan. For all syntheses yield and the epoxide content were found. The structure of thioetherglycidyl resins with the highest epoxide content was determined by elementary analysis, infrared IR, and NMR spectra. The physical and chemical properties were also defined. The investigations covered the determination of some properties of resins, cured chemically or thermally with different curatives and thermal and mechanical properties of the cured compounds.
An alternate approach to the determination of rate parameters in copolymerization
Authors: Balaraman K. S. , Kulkarni B. D. , Mashelkar R. A. 
Published: April 2003

AbstractA new method which proposes the use of a steady state CSTR is presented for the determination of rate parameters in a copolymerization system. The approach does not limit the conversion levels in the reactor and allows precise estimation of reactivity ratios. In the presence of gel effect, the suggested approach additionally reveals the cumulative variations of termination rate processes with extent of conversion. Such an a priori method which enables estimation of rate parameters in the high conversion region has not been available in the literature previously. The method proposed is illustrated using copolymerization of styrene–methyl methacrylate as a model system.
The transport phenomena of some model solutes through postcrosslinked poly(2‐hydroxyethyl methacrylate) membranes with different tactic precursors
Authors: Yoon Sung Chul , Jhon Mu Shik 
Published: April 2003

AbstractTwo series of membranes of various degree of hydration have been prepared by postcrosslinking highly syndiotactic and isotactic poly(2‐hydroxyethyl methacrylate) [P(HEMA)] with various amounts of hexamethylene diisocyanate (HMDIC). The equilibrium water content, the partition coefficient, and the permeability of the model solutes such as urea, acetamide, NaCl, 2‐propanol, and isobutanol for these membranes were measured. In addition, differential scanning calorimetry (DSC) study for the membranes was performed. The membranes of the isotactic precursor are more hydrated at 25°C compared to the ones of its syndiotactic counterpart. This may be due to the more hydrophobic nature of syndiotactic P(HEMA). The partition coefficient data show that the solutes of urea, acetamide, and NaCl are partitioned only into the water‐containing region, whereas the alcohol solutes are preferentially sorbed on to polymer matrix. The permselectivity data of urea to NaCl reveal that the permselectivity of crosslinked isotactic P(HEMA), (ISO) membranes increases as the amount of HMDIC is increased from 2.5 to 10 mol %, while the trend is reversed for crosslinked syndiotactic P(HEMA), (SYN) membranes. The apparent diffusivity order of urea, acetamide, and NaCl is not the same in those two characteristic membranes: the order is urea > NaCl > acetamide for highly crosslinked ISO membranes, and NaCl > urea > acetamide for all SYN membranes, which was compared with the free diffusion data in aqueous solution and interpreted in terms of the water‐structural orderlines within membranes.
Studies on synthetic‐polymer plates with high surface energy. IV. Determination of critical surface tension with aqueous solutions of salts
Authors: Kaneko Norio , Ohtsuka Yasuji 
Published: April 2003

AbstractThe critical surface tension (γc) of synthetic‐polymer plates with a functional group (amide, sulfonic, or carboxyl group) on their surface was determined by the Zisman plot using series of pure liquids (thiodiglycol, formamide, and water) and the aqueous solutions of the salts (NaCl, NaNO3, etc.) as a hydrogen‐bonding liquid. The Zisman plots gave a straight line, and the trends in the γc values coincide with those in the hydrophilicity anticipated from the θ values. The use of the aqueous salt solution coupled with the pure liquids as a hydrogen‐bonding liquid offers a practical determination procedure of the γc value for the materials with high surface energy.
Studies on suspension and emulsion. LIV. Shrinkage of polymer emulsion film having asymmetric porous structure
Authors: Okubo Masayoshi , Takeya Tetsuro , Tanaka Hitoshi , Matsumoto Tsunetaka 
Published: April 2003

AbstractIt was found that the film cast on a glass plate from emulsifier‐free ethyl acrylate–methyl methacrylate copolymer emulsion when separated from there shrank and curled immediately. This film had an “asymmetric” porous structure. It was discussed the relationship between the porous structure and the shrinkage due to the residual internal stress produced during film formation.
Tie chains and modulus of nylon 6 fibers
Authors: Mishra S. P. , Deopura B. L. 
Published: April 2003

AbstractA large number of nylon 6 fiber samples with varying internal structure were obtained by changing draw ratios, drawing temperature, and quenching immediately after drawing. Modulus of these samples is analyzed by Takayanagi model and fraction of tie chains is obtained. It is observed that the modulus of these samples is directly proportional to the fraction of tie chains.
Controlled release of the herbicides 2,4‐D and dichlobenil from alginate gels
Authors: Connick William J. 
Published: April 2003

AbstractThe herbicides 2,4‐D[(2,4‐dichlorophenoxy)acetic acid] and dichlobenil (2,6‐dichlorobenzonitrile) were individually incorporated into 1.6–2.8‐mm alginate gel beads by using calcium chloride and barium chloride as gellants. The release rate of each herbicide from the beads into water was greatly influenced by drying and the choice of gellant cation. Slowest release was obtained with dried samples that were gelled with barium chloride. At the slowest rates, release of 2,4‐D was complete in 14 days, while only 59% of the less‐soluble dichlobenil was released in 150 days.
Thermal and photooxidation of polyolefins in the presence of 3,5‐ditertiarybutyl 4‐hydroxybenzyl thioglycollate, zinc diethyldithio carbamate, and irganox 1076
Authors: Kolawole E. G. 
Published: April 2003

AbstractThree types of additives for polymers have been studied in polystyrene and poly(methyl methacylate). The effects of a novel thermal stabilizer 3,5‐ditertiarybutyl 4‐hydroxybenzyl thioglycollate (DBHBT), zinc diethyldithiocarbamate (ZnDEC) have been compared with the commercial antioxidant Irganox 1076. It has been found that the new antioxidant was far more superior to the commercial antioxidant. It also acts as a peroxide decomposer. It also gave considerable synergistic effects with ZnDEC both under thermal and photo degradations. Its use is being recommended instead of the present commercial ones.
Change of molecular aggregation state in amorphous region with uniaxial extension of preoriented polypropylene
Authors: Yamada K. , Takayanagi M. 
Published: April 2003

AbstractPreoriented isotactic polypropylene was uniaxially drawn at various testing directions and testing temperatures. Change of the molecular aggregation state in amorphous region with extension was elucidated by measurements of melting temperature, enthalpy of fusion, and birefringence at each stage of extension. Melting temperature depends on both crystallite thickness and orientation function of amorphous chains. It is assumed that the enthalpy change of amorphous region takes place when oriented amorphous chains are transformed into random state by heating. The ratio of the enthalpy change of amorphous region in the sample after extension to that in the sample before extension monotonously increased with increasing orientation function of amorphous chains, fa, independent of testing direction and testing temperature. Increase of true stress with drawing led to increase of fa. Increase of fa with extension depended on the testing angle θ between the testing direction and the direction of the crystal c‐axis of the preoriented sample, and fa most remarkably increased in extension at θ = 45°.
Epoxy resins: Effect of extent of mixing on properties
Authors: Bell James P. 
Published: April 2003

AbstractInhomogeneities observed in cured epoxy resins by several workers appear to be related to the effectiveness of mixing the reactants. This mixing effectiveness also has an effect on the softening temperature Tg, of DETA cured resins, of as much as 10°C. Improved mixing of both DETA and Versamid 140 cured systems resulted in substantial ultimate strength improvement, in agreement with other recent results. Samples were mixed by hand, by a concentric cylinder mechanical mixer, and by application of an electrical filed between the cylinders of the mechanical mixer while mechanical mixing was in progress.
High‐density polyethylene filled with modified chalk
Authors: Badran B. M. , Gałȩski A. , Kryszewski M. 
Published: April 2003

AbstractHigh‐density polyethylene was filled with chalk in various concentrations ranging from 10% to 60% by weight. Ethylene oxide oligomer Mw = 300 was used as a liquid modifier for chalk in the amount 0 ÷ 20 wt % of the filler. The mechanical properties of these composites showed that high density polyethylene filled with chalk have quite high ultimate elongation and impact strength while their elastic modulus and tensile strength are very near to those values for pure high density polyethylene. On the base of mechanical properties and microscopical observations, the crack and microcrack damping is attributed to the presence of ethylene oxide oligomer.
Photoinduced grafting of acrylamide onto polyethylene film by means of two‐step method
Authors: Ogiwara Yoshitaka , Takumi Masaru , Kubota Hitoshi 
Published: April 2003

AbstractBenzophenone‐coated low‐density polyethylene (LDPE) was grafted with acrylic acid (AA), methacrylic acid (MA), acrylonitrile (AN), and methyl methacrylate (MMA) in an aqueous medium by photoirradiation. The first‐step graft samples thus prepared with a grafting of about 50% were subjected to second‐step photografting with acrylamide (AAm). On AA‐ and MA‐grafted LDPE samples, the second‐step grafting of AAm was very smooth, and a high level of grafting up to 800% was attained with ease. On the other hand, grafted LDPE samples employing hydrophobic monomers, AN and MMA, had a lower percent of grafting than those with hydrophilic monomers, AA and MA. By ESR study, a thermally stable radical was found in the first‐step graft sample irradiated with light of λ > 330 nm. Mechanisms for the formation of such a radical in the first‐step graft sample are proposed, and the contribution of the radical to the second‐step grafting is discussed.
Transient diffusion through multilaminate slabs separating finite and semiinfinite baths
Authors: Spencer H. G. , Chen T. C. , Barrie J. A. 
Published: April 2003

AbstractEquations describing transient diffusion through multilaminate slabs with constant diffusion and partition coefficients for each lamina separating well‐stirred finite and semiinfinite baths are presented. Application is illustrated using a representative slab with three laminae.
Synthesis of rigid polyurethane foams from oligoester alcohols obtained from dimethyl terephthalate production wastes
Authors: Troev K. , Todoroy K. , Borisov G. 
Published: April 2003

AbstractA study was conducted to synthesize oligoester alcohols from dimethyl terephthalate production wastes via transesterification with diethylene glycol and trimethylol propane. The oligoester alcohols obtained are suitable for preparing rigid polyurethane foams. The oligoester alcohols from trimethylol propane possess good physical and mechanical properties. The oxygen indices indicate that the polyurethane foams exhibit improved resistance to combustion due to the increased content of aromatic nuclei in the oligoester alcohols.
Plasma polymerization of tetrafluoroethylene in a field‐free zone
Authors: Buzzard Peter D. , Soong David S. , Bell Alexis T. 
Published: April 2003

AbstractPlasma polymerization of tetrafluoroethylene by itself and mixed with inert gases has been studied in the field free zone inside a Faraday cage. The chemical structure was analyzed by ESCA, revealing both linear and branched products. Linear products are formed by less energetic plasmas and at low monomer residence times. Lower energy plasmas result from the use of lower powers and lower percentages of helium in the feed. Production of linear products under these conditions is probably due to lower rates of free radical and metastable formation in the plasma. Through a combination of kinetic and mass transfer effects, shorter monomer residence times under high flow rates and within short distances from the front edge of the electrode give rise to a lower concentration of free radicals at the electrode surface, producing a more linear polymer. Linear products were also formed at very high powers. This latter result is quite unexpected and is probably due to rapid gas phase polymerization. The chemical structure was not affected significantly by the substrate temperature or by hydrodynamics in this work. All of the evidence indicates that the gases were well mixed in the reaction zone for the range of process variables and for the gases studied. The deposition rate was also studied as a function of the reaction conditions. It was affected by the concentration of free radicals, the concentration of the monomer, and the substrate temperature. The observed deposition rate profile across the electrode is consistent with mass transfer and kinetic considerations governing free radical and monomer concentrations on the electrode surface. The deposition rate is greater at the lower substrate temperature used, probably due to enhanced adsorption process.