bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modeling high‐pressure gas–polymer mixtures using the sanchez‐lacombe equation of state
Authors: Kiszka M. B. , Meilchen M. A. , McHugh M. A. 
Published: April 2003

AbstractThe Sanchez‐Lacombe equation of state was used to model the sorption of high‐pressure gases into solid, amorphous polymers and molten polymers. Only one adjustable parameter per binary pair, δ12, was used in the mixing rules to correct the deviation of the characteristic pressure of the mixture, P12*, from the geometric mean. The values of δ12 which gave the best fit of the available literature data for the carbon dioxide–polymethyl methacrylate, carbon dioxide–silicone rubber, ethylene–low density polyethylene, methane–polyisobutylene, methane–low‐density and high‐density polyethylene, and methane–polystyrene systems ranged from −0.019 to 0.136. In all cases, the calculated sorption isotherms were in reasonably good agreement with the experimental data. The resultant swelling of polymethyl methacrylate and silicone rubber was also well represented by the Sanchez‐Lacombe equation of state. Because the Sanchez‐Lacombe theory is based on lattice‐fluid theory, the sorption calculations are limited to polymers which are noncrystalline, not cross‐linked or slightly crosslinked, above their glass transition temperature, or above their melting temperature. The sorption data for the amorphous polymers considered in this study were either at temperatures above the glass transition temperature of the polymer or were at sufficiently high pressures that the temperature was above the effective glass transition temperature as predicted from a theoretical relation presented by Chow.
Engineering plastics from lignin. XV. Polyurethane films from chain‐extended hydroxypropyl lignin
Authors: Kelley Stephen S. , Glasser Wolfgang G. , Ward Thomas C. 
Published: April 2003

AbstractA series of polyurethane (PU) films was prepared from chain‐extended hydroxypropyl lignins (CEHPL). In appearance, these films ranged from brittle and dark brown to rubbery and bronze. The thermal, mechanical, and network properties of these PUs were investigated by DMTA and DSC analysis. All films exhibited single Tg's which varied between −53° and 101°C, depending on lignin content. From swelling experiments, molecular weight between crosslinks (Mc) was determined and found to vary over 2.5 orders of magnitude. The Mc's were related to the change in Tg that accompanied network formation. Stress–strain experiments showed a variation in Young's modulus between 7 and 1300 MPa. Most of the variation in material properties was related to lignin content and to a lesser extent to diisocyanate type, hexamethylene diisocyanate, or toluene diisocyanate. The source of the CEHPL had no effect on the observed properties. From these results it was concluded that the properties of PUs can be controlled and engineered for a wide variety of practical uses.
Study on rough‐surface biaxially oriented polypropylene film. VII. Roughening by blending low melting point polymers
Authors: Fujiyama Mitsuyoshi , Kawamura Yoshimasa , Wakino Tetsuo , Okamoto Tomomi 
Published: April 2003

AbstractThe roughening of biaxially oriented polypropylene film using polypropylene (PP) blended with low melting point polymers such as polybutene‐1 and high‐density polyethylene as raw resin in a successively stretching tenter method has been studied for the same reasons as has the roughening of BOP utilizing β crystals. Rough‐surface BOPs with a low depth and a high density of roughness were obtained by using the blended PPs as raw resins. By combining this roughening method with the roughening method utilizing the β crystals, rough‐surface BOPs with a crater‐like large roughness and a fine roughness on the ground were obtained. These rough‐surface BOPs showed excellent impregnation properties of insulating oils.
Graft polymerization of acrylamide onto UV‐irradiated films
Authors: Uyama Y. , Ikada Y. 
Published: April 2003

AbstractGraft polymerization of acrylamide was attempted onto the surface of films preirradiated with UV radiation. The films employed are nylon 6, polypropylene, and ethylene–vinyl acetate copolymers. Following UV irradiation in air on films without photosensitizer, they were placed in monomer solution, degassed, and then heated to 50°C to effect the graft polymerization. After rigorous removal of homopolymers, polyacrylamide chains were found to be grafted in the surface region of the films to amounts up to several hundred micrograms per square centimeter of films. An ESCA study revealed the UV‐irradiated but not yet grafted surfaces to be oxidized, and formation of peroxides was strongly suggested by the reaction of irradiated films with 1,1‐diphenyl‐2‐picrylhydrazyl. It is likely that the initiator responsible for the graft polymerization is peroxides generated at and near the film surfaces upon UV irradiation. The grafted films became very slippery when contacted with water, in contrast with the films UV‐irradiated but not yet grafted.
Adsorption at the solution‐solid interface: Alkyd resin on TiO2 pigment
Authors: Janardhan R. , Gedam P. H. , Kumaran P. S. Sampath , Narasimha R. , Hussain Sajid 
Published: April 2003

AbstractGel permeation chromatography results obtained from the adsorption of alkyd from different solutions on anatase TiO2 surfaces are reported, and the influences of the solvent–resin interactions in the adsorption process are discussed, covering the thickness of the adsorbed layer, the type of molecular weight species adsorbed, and its dependence on the concentration of the solution. Resin–pigment interaction was found to be influenced by the type of solvents used.
Persulfate initiated aqueous polymerization of acrylonitrile at 50°C in an inert atmosphere of nitrogen gas
Authors: Sarkar S. , Adhikari M. S. , Banerjee M. , Konar R. S. 
Published: April 2003

AbstractThe rate of aqueous polymerization (Rp) of acrylonitrile (AN) initiated by potassium persulfate at 50°C, is given by:

where (M) stands for monomer concentrations. It has been suggested that persulfate ions in aqueous solution (pH 4 to 7) decompose not only via the well established paths viz.: (A) and (B)

but also via (C) and (D) in the presence of AN monomer:

where (M˙j)w is a water‐soluble monomeric/oligomeric free radical. The separating polymer phase remains in aqueous solution as a stable colloid, or a precipitate, depending on the ionic strength of the medium. At high conversions in general, and even at low conversions at relatively higher monomer concentrations, (1.20 m/dm3), the colloidal latex polymer was found to have a tendency to form gel, and the viscosity of the medium was found to increase with conversions. The distribution coefficient of the monomer between the polymer and the aqueous phases was found to be (0.50 ± 0.10) at 50°C in the presence and absence of electrolytes (K2SO4 7.5 × 10−3 m/dm3). The termination rate constants in the aqueous phase (ktw) and in the polymer phase (ktp) have been estimated as given below:

taking kp of Dainton et al. as 6.22 × 04 (dm3/m/s) at 50°C.
Characterization of some poly(methyl methacrylate)s prepared by emulsifier‐free emulsion polymerization in presence of some organic ligands and their nickel complexes
Authors: Sayyah S. M. , El‐Hamouly S. H. H. , Abd El‐Ghaffar M. A. 
Published: April 2003

AbstractThe aqueous polymerization of methyl methacrylate (MMA) was studied using sodium bisulfite as initiator in absence and presence of tetraoxalyl urea (TOU), tetraoxalyl thiourea (TOthioU) and tetraoxalyl paraphenylene diamine (TOp‐phD). The effect of their nickel complexes on the polymerization rate has also been studied. Ligands with free carboxyl groups have a retarding effect on the polymerization reaction, while their nickel complexes have a catalytic effect. The polymers obtained in presence of nickel complexes were found to have wider molecular weight distribution than those obtained in their absence; this was deduced by thin layer chromatographic analysis in a binary mixture (benzene/methanol). The apparent energy of activation was found to be 5.83 × 104 J/mol, 1.87 × 104 J/mol, 2.11 × 104 J/mol, and 3.95 × 104 J/mol in absence and in presence of 0.5 g of Ni complex of TOp‐phD, TOthioU and TOU, respectively.
Immobilization of poly(ethylene oxide) on poly(ethylene terephthalate) using a plasma polymerization process
Authors: Gombotz W. R. , Guanghui W. , Hoffman A. S. 
Published: April 2003

AbstractPoly(ethylene oxide) (PEO) has been covalently immobilized on poly(ethylene terephthalate) (PET) films using a radio frequency glow discharge polymer deposition process, followed by chemical coupling. Amino or hydroxyl groups were introduced onto the surface of the PET by exposing the films to allylamine and allyl alcohol plasmas. These functional groups were activated with cyanuric chloride, and then they were reacted with PEO. ESCA and water contact angle studies were used to characterize the surfaces of these films during the different stages of the reaction. The films containing the higher molecular weight PEO exhibited an increase in the CO peak of the Cls ESCA spectrum and an increase in oxygen content on the film surfaces. Increasing the molecular weight of the PEO attached to the PET also resulted in an increased wettability of the films.
Addition polyimides. II. Synthesis and characterization of bisitaconimide prepolymers
Authors: Ninan K. N. , George Rene , Krishnan K. , Rao K. V. C. 
Published: April 2003

AbstractN,N′‐bis(3,3′‐itaconimidophenyl) sulfone has been synthesized by reacting itaconic anhydride with 3,3′‐diamino diphenyl sulfone. The bisitaconimides and the intermediates were characterized by chemical analysis, IR, NMR, TG, and GPC. The degree of polymerization (DP) of the prepolymers of the bisitaconimide was followed by GPC and from the NMR data on vinylidene and aromatic proton ratios. The correlation between DP and intrinsic viscosity of the prepolymers was made use of to determine the Mark–Houwink constants (K and α). The thermal stability and the decomposition kinetics of the prepolymers were evaluated from TG data. The kinetic parameters, viz. energy of activation, E, and preexponential factor A, were computed using four nonisothermal integral equations, and their values are not appreciably affected by the degree of polymerization, within the range studied.
Suspension polymerization of vinyl chloride. I. Influence of viscosity of suspension medium on resin properties
Authors: Cebollada A. F. , Schmidt M. J. , Farber J. N. , Capiati N. J. , Vallés E. M. 
Published: April 2003

AbstractThe suspension polymerization of vinyl chloride is studied in a bench‐scale reactor adequately reproducing reaction conditions and resin properties of industrial relevance. The evolution of particle morphology is analyzed at different stages of conversion, and a model for particle formation is verified. The influence of viscosity of the suspension medium is analyzed in relation to molecular weight distribution and particle morphology.
Effect of ultraviolet irradiation on the selective transport of alkali metal ions through 2,3‐epithiopropyl methacrylate–methacrylic acid copolymer membrane
Authors: Nonaka Takamasa , Maeda Hirotoshi , Nakayama Morio , Egawa Hiroaki 
Published: April 2003

AbstractCationic exchange membranes were prepared with 2,3‐epithiopropyl methacrylate (ETMA)–methacrylic acid (MAc) copolymer. Transport of alkali metal ions against their concentration gradient through the membranes was investigated by using the system which contains HCl (left side) and alkali metal solution including two kinds of alkali hydroxides (right side). The effect of ultraviolet (UV) irradiation on the selective transport of alkali metal ions through the ETMA–MAc copolymer membranes was investigated. The membranes were irradiated with a 6‐W low pressure mercury lamp at a distance of 10 cm at room temperature in air. The transport selectivity could be increased by using UV‐irradiated membranes and the selectivity increased with increasing irradiation time up to 2–3 h, although the transport rate of alkali metal ions decreased with increasing time of UV irradiation. The maximum selectivity of K+/Na+, Na+/Li+, and K+/Li+ were 1.7, 2.0, and 4.2, respectively. In order to explain this phenomena, the effect of UV irradiation on the properties of the membranes was studied. It was concluded that the increase of the selectivity is attributed to the formation of the dense membrane by photocrosslinking of the membrane by UV irradiation.
Characterization of poly(3,3‐bisethoxymethyl oxetane) and poly(3,3‐bisazidomethyl oxetane) and their block copolymers
Authors: Murphy E. A. , Ntozakhe T. , Murphy C. J. , Fay J. J. , Sperling L. H. , Manser G. E. 
Published: April 2003

AbstractThe homopolymers, poly(3,3‐bisethoxymethyl oxetane) (polyBEMO), poly(3,3‐bisazidomethyl oxetane) (polyBAMO), and triblock copolymers based on these homopolymers and a statistical copolymer center block composed of BAMO and 3‐azidomethyl‐3‐methyl oxetane AMMO were synthesized and characterized by differential scanning calorimetry, modulus‐temperature, optical microscopy, membrane osmometry, and solution and melt viscosity. The values of K and a for the Mark‐Houwink equation were found to be 7.29 × 10−3 mL/g and 0.80, respectively, for polyBEMO at 25°C using number‐average molecular weights. Glass transition temperatures were in the range −25 to −40°C and melting temperatures were between 65 and 90°C for all polymers. The melting temperature was found to increase as expected with molecular weight. Melt viscosities of triblock copolymers with polyBAMO end blocks were at least an order of magnitude lower than those with polyBEMO end blocks and clear optically, suggesting that the polyBAMO‐based triblock copolymers formed one phase in the melt, while the polyBEMO‐based triblock materials (milk white) phase separated. The addition of filler raised the melt viscosity to a level between that predicted by the Guth‐Smallwood and the Mooney equations.
Long term oil‐seal embrittlement
Authors: Lawandy S. N. , Wassef M. T. 
Published: April 2003

AbstractThe effect of antioxidant concentration in mineral oil on polychloroprene rubber vulcanizate, based on different types of carbon black, has been studied. This study shows that, with the increase of antioxidant, the percentage volume swelling of the rubber increases, the hardness of the rubber decreases, and the embrittlement time is prolonged. The properties achieved are important for oil seal manufacturers.
Multiple transitions in atactic 1,2‐polybutadienes observed from dynamic mechanical and dielectric relaxation data
Authors: Ni Shaoru , Yu Fusheng , Shen Lianfang , Qian Baogong 
Published: April 2003

AbstractDetailed investigation by dynamic mechanical, dielectric and 13C‐NMR relaxation spectroscopies over a temperature range from −180 to 100°C reveals the multiple transitions in atactic 1,2‐polybutadienes, which are denoted as T11, α, β, γ, and δ in conformity with reducing temperature. The spectroscopic data obtained show that α transition is the glass transition of the samples, β‐and γ‐relaxations are likely to be related to the flexibility of the main chain and the side chain motion, respectively, and δ loss process seems to be associated with the defects and inhomogeneity in structure. T11 transition observed in the dielectric relaxation spectra may be manifested by the abrupt broadening of the resonance peaks in solid‐state 13C‐NMR spectra.
A new approach for the production of cellulose acetate: Acetylation of mechanical pulp with subsequent isolation of cellulose acetate by differential solubility
Authors: Barkalow D. G. , Rowell R. M. , Young R. A. 
Published: April 2003

AbstractA heretofore uninvestigated approach to the production of cellulose acetate, the acetylation of whole wood pulp with subsequent isolation of the cellulose derivative by differential solubility, is described. The mechanical pulp used was produced by refining aspen wood chips with a disc refiner. Two conventional acetylation techniques, the fibrous and solution process, were employed to acetylato all components of the pulp. The cellulose acetate was isolated from the acetylated lignin and hemicellulose by dissolving in dichloromethane/methanol (9:1, v/v). The advantage of this new approach is that the high cost involved in using an extensively purified dissolving pulp are avoided. Both acetylation techniques yielded a product that was about 84% cellulose acetate. The remaining acetylated components were lignin and hemicellulose. The yield of cellulose acetate, based on the cellulose content of the original pulp and the product, was 75–80%.
Chemical modification of poly(substituted‐acetylene). IV. Pervaporation of organic liquid/water mixture through poly(1‐phenyl‐1‐propyne)/polydimethylsiloxane graft copolymer membrane
Authors: Nagase Yu , Mori Shigehiro , Matsui Kiyohide 
Published: April 2003

AbstractPoly(1‐phenyl‐1‐propyne)/polydimethysiloxane (PPP/PDMS) graft copolymer membranes having various PDMS content were prepared by solvent casting method, and the permeation characteristics at pervaporation were examined upon the aqueous solutions containing organic liquids such as alcohols, acetone, dioxane, acetonitrile, pyridine, and DMF. At pervaporation of ethanol/water mixture, preferential permeation of ethanol was observed for all the copolymer membranes, although PPP membrane showed water permselectivity. The permselectivity of the copolymer membrane also depended on operation temperature, but was independent on the thickness of the membrane. Furthermore, an excellent permselectivity of organic liquids was observed at the pervaporation of several organic liquid/water mixtures except in the case of DMF/water mixture. Observed high selectivity is thought to be due to the depression of the membrane swelling and the high solubility of the liquids into the membrane.
A solid solvent as processing aid for polystyrene
Authors: Chung C. I. , Cao M. Y. , Liu C. , Min K. J. 
Published: April 2003

AbstractMany polymers suffer from excessive heat generation during processing due to high viscosity, and reduction of viscosity is desired to control the melt temperature during processing. The concept of solid solvent was recently proposed based on thermally reversible compatibility between a polymer‐additive pair. Benzenesulfonamide was found to be virtually a perfect solid solvent for polystyrene, and this finding clearly proves that solid solvents can be used as processing aid for polymers to effectively reduce the viscosity.
Preparation of high‐strength poly(vinyl alcohol) fibers by crosslinking wet spinning
Authors: Fujiwara Hiroshi , Shibayama Mitsuhiro , Chen Jing Hui , Nomura Shunji 
Published: April 2003

AbstractHigh‐strength poly(vinyl alcohol) (PVA) fiber was obtained by the crosslinking wet‐spinning technique, which is an improved technique of the conventional non‐crosslinked type wet‐spinning of PVA. High tensile strength as well as high Young's modulus was achieved by introduction of the borate ion‐aided crosslinks during the coagulation process. The drawability of the as‐spun fiber greatly depends on the fiber thickness. The thinner the fiber, the higher the drawability. Since thinner fiber is subject to a very high shear rate on extrusion, the crosslinks introduced are believed to maintain topological memory of the oriented chains, which have a low density of entanglements. This allows drawing the fiber to a higher draw ratio. The strength and Young's modulus of the resultant highly drawn PVA fiber were achieved to be 22 g/d (2.3 GPa) and 430 g/d (50 GPa), respectively. The mechanism of the spinning was discussed and the spinning condition was carefully examined in order to optimize the final mechanical properties of the PVA fibers.
Sorption and transport of CO2 in poly(ethylene terephthalate) crystallized by sorption of high‐pressure CO2
Authors: Hirose Takuji , Mizoguchi Keishin , Kamiya Yoshinori , Terada Katsuhiko 
Published: April 2003

AbstractSorption and permeation of CO2 in poly(ethylene terephthalate) crystallized by sorption of high‐pressure CO2 were examined below 1 atm at temperatures from 15 to 65°C. A large solubility and a high permeability of CO2 in this specimen were observed compared to poly(ethylene terephthalate) crystallized by thermal annealing to a similar degree. A large unrelaxed volume is expected to be left in the specimen after removal of high‐pressure CO2 compared to the data of other PET samples. The thermal history during the measurements up to 65°C, which causes relaxation of the specimen, was shown to decrease CO2 solubility. On the other hand, permeation data after annealing show not only decreased permeability but also increased apparent diffusivity. The results mean a lower mobility of gases sorbed in the unrelaxed volume than that of ordinarily dissolved gases, which corresponds to the partial immobilization model.
Free radical copolymerization of poly(n‐butyl methacrylate) onto polychloroprene
Authors: Srinivasan K. S. V. , Radhakrishnan N. , Pillai M. Kuttalam 
Published: April 2003

AbstractGraft copolymerization of n‐butyl methacrylate onto polychloroprene was carried out in toluene using benzoyl peroxide as an initiator. The polychloroprene‐g‐poly(n‐butyl methacrylate) was isolated from the copolymerization product by extracting with hexane. Infrared (IR) spectra and nuclear magnetic resonance (NMR) of graft copolymer showed the occurrence of grafting. Percentage of grafting and grafting efficiency calculated under different experimental conditions were discussed. The mechanism of grafting seems to occur by chain transfer, as evidenced by a decrease in chlorine content during the experiment.
X‐ray‐induced reactions and resist features of polydibutylgermane
Authors: Ban Hiroshi , Deguchi Kimiyoshi , Tanaka Akinobu 
Published: April 2003

AbstractPolydibutylgermane undergoes oxidation reaction and chain scission under X‐ray exposure. These reactions are the same as those observed for ultraviolet irradiation. Positive resist patterns can be fabricated by X‐ray lithography.
Stabilization of poly(vinyl chloride). X. Synergisms between epoxidized polybutadienes and metal soaps on the stabilization of poly(vinyl chloride)
Authors: Iida Takeo , Kawato Junji , Tanie Sachiko , Gotō Kuio 
Published: April 2003

AbstractEffects of epoxidized 1,2‐ or 1,4‐polybutadienes on the zinc stearate/calcium stearate synergetic soap‐induced thermal stabilization of poly(vinyl chloride) (PVC) were investigated by colorimetry. The remarkable stabilization effects of epoxidized polybutadienes could not be observed on the PVC films without synergetic soaps, while the stabilization of PVC was markedly enhanced by combined use of epoxidized polybutadienes with synergetic soaps. Excessive coloration of cool color‐producing zinc chloride‐polyene complexes that were the source of abrupt discoloration of stabilized PVC was retarded by using epoxidized polybutadienes together with synergetic soap. The synergism of epoxidized polybutadienes was enhanced with increasing epoxy contents. Moreover, the effect is also clearly dependent on degree of dispersion of epoxidized polybutadienes in PVC. Further colorimetries, infrared (IR), and X‐ray photoelectron spectroscopies on the various PVC‐containing epoxidized polybutadienes and zinc chloride indicated that the epoxy groups capture the zinc chloride. The synergistic effect between epoxidized polybutadienes and metal soap was ascribed to epoxidized polybutadienes serving as acceptors for the excessive cool color‐producing zinc chloride produced by zinc stearate to retard the abrupt discoloration of stabilized PVC. The plate‐out phenomenon appeared during the molding process of PVC‐containing epoxy compounds was considerably retarded by epoxidized polybutadienes which modified polyols. The polyol‐modifying epoxidized polybutadienes also exhibited a marked effect on PVC stabilization with metal soap.