bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structure and properties of microporous membranes prepared by applying phase separation during polymerization
Authors: Mizutani Yukio , Nishimura Masakatsu 
Published: April 2003

AbstractPorous membranes of poly(vinyl chloride) were obtained from cation exchange membranes prepared by the soaking and paste method, by selective decomposition of the cation exchange resin component. The structure and properties of the membranes as filters were investigated by scanning electron microscopy, infrared analysis, water permeability measurement, and determiantion of rejections for some solutes and dispersers with widely differing sizes. They completely rejected two kinds of bacteria and polymer particles with a diameter of about 0.1 μm. The rejection of hemoglobin ranged from 90 to 100%, depending upon the preparative conditions. Heat treatment of the cation exchange membranes increased water permeability of the resulting PVC porous membranes and decreased hemoglobin rejection in varying degrees, depending upon the treatment temperature.
Polymerization of alkyl acrylates and alkyl methacrylates with starch
Authors: Fanta George F. , Burr Robert C. , Doane Wiliam M. 
Published: April 2003

AbstractA series of C4‐C12 alkyl acrylates and methacrylates was polymerized with starch by irradiating starch–monomer mixtures with 60Co. Homopolymers were extracted with cyclohexane. The amounts of insoluble versus soluble synthetic polymer in polymerization run with alkyl acrylates varied less with the chain length of the alkyl substuent than in the polymerizations run with alkyl acrylates varied less with the chain length of the alkyl substituent than in the polymerizations run with alkyl methacrylates; and the poly(alkyl acrylate) contents of cyclohexane‐insoluble fractions were all in the 38–45% range. Synthetic polymer contents of the products from butyl, hexyl, and decyl methacrylates were also close to this range. Octyl and lauryl methacrylate, however, gave high conversions to cyclohexane‐soluble poly(alkyl methacrylate) along with little or no unextractable synthetic polymer in the starch‐containing fractions. Poly(lauryl methacrylate) could be rendered insoluble by incorporating a small amount of tetramethylene glycol dimethacrylate in the polymerization mixture. In a series of polymerizations run with hexyl acrylate and hexyl methacrylate, lower irradiation doses led to more cyclohexane‐soluble polymer and less synthetic polymer in the starch‐containing fractions. Enzymatic digestion of starch‐soluble polymer and less synthetic polymer in the starch‐containing fractions. Enzymatic digestion of starch‐containing polymers gave synthetic polymer fractions that were largely insoluble in cyclohexane. Crosslinking is, therefore, probably taking place during these polymerizations; however, we could not eliminate the possibility that reduced solubility was caused by small amounts of residual carbohydrate in these polymer fractions. Ceric ammonium nitrate‐initiated polymerizations of butyl acrylate, hexyl acrylate, and butyl methacrylate with starch gave cyclohexane‐insoluble polymers that contained 33–39% synthetic polymer. The higher alkyl acrylates and methacrylates produced little or no polymer under these conditions. Starch‐containing fractions were tested as absorbents for hydrocarbons. Products prepared from decyl acrylate and lauryl acryle acrylate absorbed about 9 g of isooctane per 1 g of polymer, whereas the lowrer alkyl monomers gave polymers with lower absorbency.
Property–composition dependence of polyurethane–poly(vinyl chloride) polyblends
Authors: Kalfoglou Nikos K. 
Published: April 2003

AbstractThe dynamic mechanical properties of polyblends of a polyurethane (PU) elastomer and poly(vinylchloride) (PVC) at five compositions were studied at 110 Hz, between −120 and 120°C. The study also included tensile testing at 25°C, and examination of polyblend morphology and fire‐retardant properties. The results were analyzed using suitable two‐phase mechanics models valid for such systems. This analysis, together with the morphological evidence and the thermomechanical spectra, indicate that these polymer alloys are essentially heterogeneous and their useful mechanical properties are due to good adhesion between the two phases. This conclusion is also corroborated by the tensile properties study. Fire retardancy is significant only above ∼60% by weight of PVC.
Preparation of ion‐containing elastomers by emulsion copolymerization of dienes with olefinic sulfonic acid salts
Authors: Siadat B. , Oster B. , Lenz R. W. 
Published: April 2003

AbstractProcedures were developed for the emulsion copolymerization of either butadiene or isoprene with several different water‐soluble monomers containing sulfonic acid salt groups, primarily with sodium styrenesulfonate, for the preparation of ionomer elastomers. By the use of a nonionic surfactant and a two‐component redox initiator, which was based on a water‐soluble reducing agent and a hydrophobic peroxide, copolymers with sufficient amounts of the ionic monomer could be prepared. Unusual effects of conversion on rate, copolymer composition, and molecular weight were observed and attributed to special effects caused by the ionic monomers. The copolymers were soluble in mixed hydrocarbon–alcohol solvent systems.
Influence of shearing history on the rheological properties and processability of branched polymers. IV. Capillary flow and die swell of low‐density polyethylene
Authors: Rokudai Minoru , Fujiki Tokio 
Published: April 2003

AbstractLow‐density polyethylene (LDPE) melts show anomalous rheological behavior; their viscoelastic properties vary with their shearing histories although their molecular structural parameters do not change. Capillary flow and die swell behavior were dependent not only on the experimental conditions such as temperature or shear stress but also on the processing index (PI), which was introduced in a preceding article in order to quantify the anomalous rheological behavior of LDPE melts. In addition, it was found that the flow activation energy at constant shear stress also varied with the shearing histories. The experimental findings are discussed in terms of the rheological flow units of LDPE melts.
Space charge limited currents in pure and iodinated cellulose acetate films
Authors: Kumar Ashok , Nath Rabinder 
Published: April 2003

AbstractCurrent as a function of voltage has been studied in pure and iodine doped cellulose acetate in the temperature range 313–373 K. The space charge limited currents (SCLC) have been found to exist in pure and doped samples. The temperature dependence of conductivity is found to correspond to two activation energies. The activation energies calculated from conductivity vs. temperature plots for ohmic and SCLC regions were almost equal showing the extrinsic nature of conduction. The break point at 78°C in conductivity vs temperature plots for pure cellulose acetate may correspond to effective glass transition temperature (T′g). This has been verified from the differential thermal analysis studies. The effect of iodine doping on the electrical conduction in cellulose acetate has been investigated and the results are reported. The infrared studies reveal that iodine stays in the polymer as a neutral molecule and some of which may interact with the polymer molecules.
The effect of heat setting on the structure and mechanical properties of poly(ethylene terephthalate) fiber. III. Anelastic properties and their dependence on structure
Authors: Gupta V. B. , Kumar Satish 
Published: April 2003

AbstractViscoelastic parameters for poly(ethylene terephthalate) (PET) fibers heat set under different conditions were determined at 110 Hz between room temperature and about 200°C. The correlation of dynamic mechanical properties with structure and their dependence on the temperature of the measurement are discussed. It was found that in addition to the structural parameters such as degree of crystallinity, crystallite and amorphous orientation, etc., morphological factors such as size and distribution of crystallites also influence the dynamic mechanical properties. The activation energy of the α‐transition is reported, and the effect of the distribution of relaxation times on the activation energy is discussed.
Assessment of the adhesive bond properties of allyl 2‐cyanoacrylate
Authors: Kotzev D. L. , Ward T. C. , Dwight D. W. 
Published: April 2003

AbstractThe adhesive bond of allyl 2‐cyanoacrylate between steel substrates has been analyzed and compared to that of ethyl 2‐cyanoacrylate. Mechanical strength as well as thermomechanical, calorimetric, thermogravimetric, and dynamic mechanical response was observed. It was demonstrated that the allyl 2‐cyanoacrylate bonds exhibit improved temperature resistance owing to the formation of heat‐induced crosslinks in the adhesive layer, resulting in much improved lap‐shear strengths. Scanning electron microscopy of the fracture surfaces showed that plastic deformation occurred in the allyl 2‐cyanoacrylate adhesive after thermal aging, while interfacial and brittle failure dominated all other cases.
Multiple molecular relaxations of hot‐drawn and quenched polymers above their glass transition temperatures
Authors: Kato T. , Yanagihara N. 
Published: April 2003

AbstractThermal shrinkage of highly hot‐drawn and quenched poly(methyl methacrylate) and polycarbonate of bisphenol A were measured. PMMA shows three‐step thermal shrinkage under suitable experimental conditions above its glass transition temperature (Tg). Polycarbonate exhibits four kinds of molecular relaxation associated with shrinkage around and above its Tg. The effect of hot‐drawing and quenching conditions on shrinking behavior is discussed. Almost all of the molecular relaxations are observed above Tg. The molecular origins of the relaxations are discussed in relation with the so‐called T11 transitions of polymers.
Polymer gamma dosimeter
Authors: Chung Woon H. 
Published: April 2003

AbstractA chemical dosimeter has been developed based on the gas evolution of polymers by γ radiation. The polymers used in this dosimetry were polyacrylamide, poly(vinyl alcohol), and polystyrene. The irradiating γ source was a 60Co annular cell calibrated with the Fricke dosimeter, an average dose rate being 630 rad/min. The irradiated samples were aqueous solution, i.e., polyacrylamide oxygen saturated in water, poly(vinyl alcohol) aerated in water, and polystyrene oxygen saturated in carbon tetrachloride. A manometer system was used as the gas‐measuring device. It was found that the dosimeter showed good linearity above 1 Mrad.
Adhesion of glow discharge polymers
Authors: Sharma Ashok K. , Millich Frank , Hellmuth Eckhard W. 
Published: April 2003

AbstractVarious reaction parameters in a propylene glow discharge polymerization were investigated with the objective of synthesizing films having good adhesion to metal and glass substrate. Monomer flow rate (at a constant pumping efficiency) was found to exert a significant effect on the quality of polymer adhesion to substrates. Good adhering polymeric films were obtained only at high flow rates where the deposition rate decreases with an increase in monomer flow rate. This observation applied also to ethylene, propane, allyl bromide, and ϵ‐caprolactam. Transmission electron microscopy of the freshly deposited polymer films indicated a defect‐free structure of the polymer surface obtained at high flow rates. The polymer surface obtained at low flow rates had a bead structure superimposed by uniformly placed circular defects.
Radiation‐induced oxidative degradation of poly(vinyl chloride)
Authors: Hegazy El‐Sayed A. , Seguchi Tadao , Machi Sueo 
Published: April 2003

AbstractGas evolution and oxygen consumption in the γ‐irradiation of PVC were studied. The gas evolution and the oxidative degradation are retarded by the presence of plasticizers and stabilizers. TheG(HCI) andG(H2) and 8 and 0.24 for the irradiation of pure PVC under vacuum and 0.02 and 0.14 for that of plasticized PVC, respectively. Gas evolution increases in the presence of oxygen, specially for the pure PVC. TheG(–O2) values for the pure and plasticized PVC are 30 and 12, respectively. The dependence of gas evolution and oxygen consumption on the oxygen pressure is more pronounced for the plasticized PVC than pure PVC because the oxygen diffusion is controlled.
Structural changes in partially oriented polyester yarns subjected to dry and wet heat
Authors: Warwicker J. O. , Graham S. G. 
Published: April 2003

AbstractAn examination by X‐ray, birefringence, and infrared methods was carried out on partially oriented polyester yarns subjected to dry and wet heat under varying tensions that allowed shrinkage and extension processes to occur. The results can be interpreted in terms of a two‐phase morphology in which one phase is a network and the other crystalline. On this basis the evidence suggests that the crystalline phase is composed of extended chains and the network of randomly folded chains with cohesion points randomly distributed between them.
Nylon 6 water‐permeable membranes prepared by electron beam radiation‐induced graft copolymerization
Authors: Haruvy Yair , Rajbenbach Aryeh L. 
Published: April 2003

AbstractNylon 6 films, 25 μm thick, were grafted with polar monomers in aqueous solution following preirradiation with a 550‐kV electron beam accelerator. The graft yield rose linearly with grafting period up to 100% graft and leveled off at a graft yield above 150%. At 100 to 200% graft of several acrylic acid derivatives onto the nylon 6 films, water permeation rates comparable to those of PVA and cellophane films were observed. These high water permeation rates of the grafted nylon films were considered as an indication that some of the acrylate copolymers penetrated throughout the matrix of the host polymer. The highest rates of water permeability were observed in nylon acrylamide grafts.
Adhesion of glow discharge polymers to metals and polymers
Authors: Inagaki N. , Yasuda H. 
Published: April 2003

AbstractAdhesion of glow discharge polymers to metals and polymers in an adhesive joint was measured by lap‐shear test and immersion in hot water of 70°C °C for an extended time. A glow discharge polymer was deposited onto polymers [polyethylene and poly(tetrafluoroethylene)] and metals (aluminum and stainless steel) prior to when the polymer and metal were joined. It is found that the lap‐shear strength is enhanced by coating the surfaces of these substrates with plasma film produced from methane, ethylene, and acetylene, and that deterioration of the adhesive bonding part, when immersed in hot water of 70°C, is strongly dependent on the gas used as well as operational conditions where a polymer film is formed. The adhesion of a polymer produced from methane on the polymer and metal is strong enough to apply for durable, adhesive joints.
Solubility of phenolic antioxidants in polyolefins
Authors: Billingham N. C. , Calvert P. D. , Manke A. S. 
Published: April 2003

AbstractThe solubilities of six phenolic antioxidants in polypropylene and polyethylene were measured between 50°C and 100°C. Measurements were also made of their solubilities in a range of liquid alkanes. The measured solubilities at 70°C were consistent with regular solution theory and could be used to predict values to within one half of an order of magnitude. No simple correlation was found when regular solution theory was applied to predict the dependence of solubility on either temperature or the molar volume of the solvent. Hence, contrary to previous reports, the relative solubilities of antioxidants, measured at high temperatures or in alkane solvents, cannot be used to estimate their relative solubilities in polymers at room temperature.
Aliphatic polyesters. I. The degradation of poly(ϵ‐caprolactone) in vivo
Authors: Pitt C. G. , Chasalow F. I. , Hibionada Y. M. , Klimas D. M. , Schindler A. 
Published: April 2003

AbstractThe degradation of poly(ϵ‐caprolactone) in rabbits, rats, and water was studied by measurement of changes in intrinsic viscosity, molecular weight, crystallinity, Young's modulus, and weight. Degradation proceeds by nonenzymatic random hydrolytic cleavage of ester linkages. The process is autocatalytic, and the kinetic relationship Mn/Mno = exp(–kt) is observed until the Mn has decreased to approximately 5000. Significant weight loss is not observed until this point but, once initiated, the rate of weight loss depends markedly on the particle size. Chain scission is associated with an increase in crystallinity, which partly determines the rate of degradation.
Study on radiation grafting of acrylic acid onto fluorine‐containing polymers. II. Properties of membrane obtained by preirradiation grafting onto poly(tetrafluoroethylene)
Authors: Hegazy El‐Sayed A. , Ishigaki Isao , Rabie Abdelgawad , Dessouki Ahmed M. , Okamoto Jiro 
Published: April 2003

AbstractSome properties of the membranes obtained by the preirradiation grafting of acrylic acid onto poly(tetrafluoroethylene) (PTFE) film have been studied. The dimensional change by grafting and swelling, water uptake, electric conductivity, and mechanical properties of the grafted PTFE films were measured and were found to increase as the grafting proceeds. These properties were found to be dependent mainly on the degree of grafting regardless of grafting conditions except higher monomer concentration (80 wt %). The electric conductivity and mechanical properties of the membranes at 80 wt % monomer concentration is lower than those at a lower monomer concentration. The results suggest that the membranes obtained at 80‐wt % acrylic acid solution have a somewhat heterogeneous distribution of electrolyte groups as compared with those prepared at a monomer concentration less than 60 wt %. X‐ray microscopy of the grafted films revealed that the grafting begins at the part close to the film surface and proceeds into the center with progressive diffusion of monomer to give finally the homogeneous distribution of electrolyte groups. The membranes show good electrochemical and mechanical properties which make them acceptable for the practical uses as cation exchange membrane.
Copolyester studies. VII. The dyeing behavior of undrawn fibers derived from tetramethylene terephthalate: Poly(tetramethylene oxide) random block copolymers
Authors: Boussias C. M. , Peters R. H. , Still R. H. 
Published: April 2003

AbstractA series of copolymers based on poly(tetramethylene terephthalate) containing poly(tetramethylene oxide) blocks whose molecular weights ranged from 1000 to 5000 in concentrations from 10 to 30% by weight was prepared. The polymers were melt spun into fibers and the undrawn fibers dyed with a disperse dye at three temperatures. The equibrium adsorption and diffusion coefficient of the dye increased with both the molecular weight and concentration of the polyether. The equilibrium adsorption varied linearly with both the molecular weight and concentration. It has been assumed that the equilibrium dye partition coefficient KM gives a parameter of the accessibility, V, of the fiber for dye. If the diffusion coefficient DM is given by DM = VDo/τ, where Do is the diffusion coefficient of the dye in the amorphous regions and τ is a tortuosity factor, a good correlation can be obtained between KM and DM, suggesting that changes in Do/τ vary in a systematic fashion.
The adhesion of viscoelastic polymers to wool and polyethylene
Authors: Bateup Brett O. , Souren Illa 
Published: April 2003

AbstractThe relative magnitude of the rate‐dependent peel force for different polymers adhering to polyethylene could be qualitatively predicted from the measured hysteresis of polymer films during stress—strain testing. Calculated values of the energy dissipated at the polymer/polyethylene interface during peeling were of the same order of magnitude as hysteresis values measured at a much lower stress than the breaking stress of the weakest polymer. This was consistent with low values of polymer/polyethylene intrinsic bond strengths expected for pure van der Waals bonding across the interface. In the wool/polymer system, fiber/polymer adhesion was an important facor in determining the shrink‐resist effectiveness (sre) of polymers applied to wool fabric. Correlation between polymer shrink‐resist effectiveness and polymer hysteresis was observed for two series of polymers whose intrinsic wool/polymer bond strengths could be assumed constant. In both cases, cohesive failure in the polymer occurred and hysteresis had to be measured just below the breaking stress of each polymer.
Studies of polymer electrets. I. Factors governing the stabilities of homoelectrets obtained from poly(1‐olefin)s
Authors: Mishra Anu 
Published: April 2003

AbstractVarious poly(1‐olefin)s have been studied as homoelectrets and their stabilities under different environmental conditions have been determined. It has been found that the stabilities of the homoelectrets, prepared from these polymers, depend on their volume resistivities, degrees of crystallinity, and the temperatures at which the crystalline domains of these polymers undergo transitional motions. Excellent stabilities have been exhibited by the homoelectrets prepared from poly(3‐methyl‐1‐butene), poly(4‐methyl‐1‐pentene) and other similar isotactic poly(1‐olefin)s with pendant branched side chains. It is postulated that the charged particles are trapped at the crystalline/amorphous interfaces in these polymers and the bulky alkyl substituents stabilize the charged particles by raising the transition temperatures of these polymers as well as by providing some additional chemical interaction sites.
A thermal analysis study of bisphenol‐A‐polycarbonate–dimethylsiloxane block copolymers
Authors: Grubbs Gary R. , Kleppick Mary E. , Magill J. H. 
Published: April 2003

AbstractThe thermogravimetric analysis (TGA) of three block copolymers of poly(dimethylsiloxane)–Bisphenol‐A‐polycarbonate was measured in nitrogen and air from just above room temperature to 1000 K. Measurements were made on a Perkin‐Elmer TGS‐2 system equipped with a System 4 microprocessor controller. Weight loss curves were obtained for heating rates ranging from 1.5 (or lower) to 80°C/min. Results were analyzed according to the method of Flynn and Wall. Two degradation reactions were observed in air and in nitrogen, respectively. In air, the activation energy was found to be 28–35 kcal/mol. In the inert atmosphere, activation energies were 44±3 kcal/mol and 11–27 kcal/mol, respectively. No straightforward relationship was found between the thermal stability of the copolymers and their composition. The morphology of char residues formed at 80°C/min heating rate to 1000 K have been examined in relation to the Si content. The degree of char formation at different heating rates has been established in nitrogen and in air, respectively.
Dynamic mechanial properties of sulfonated cyclized cis‐1,4‐polyisoprene
Authors: Zhou Zheng Long , Eisenberg A. 
Published: April 2003

AbstractAcetyl sulfate was used as sulfonating agent for the sulfonation of cis‐1,4‐polyisoprene. IR and NMR spectra showed that the sulfonation was accompanied by extensive cyclization. A series of DSC and loss tangent studies of both the sodium salts and the methyl esters was undertaken. It was found that cyclization exerts a profound influence on the micrbrownian segmental motion of the hydrocarbon matrix and is the dominant factor in raising the glass transition temperatures. However, the differences in the mechanical properties between salts and esters suggest that the presence of ions does influence the melt viscosities and shear moduli of the sulfonated cyclized rubbers; this influence can be minimized by esterification or water absorption. It is seen that the ionic effects in these materials are quite typical of those encountered in a wide range of other ionomers.