bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biodegradability of polyesters having tetrahydropyran rings in their backbones
Authors: Okada Masahiko , Ito Shinji , Aoi Keigo , Atsumi Miharu 
Published: April 2003

AbstractBiodegradability of several homo‐ and copolyesters, containing tetrahydropyran rings in their backbones with or without pendant groups, was investigated by degradation tests, both in soil and in an activated sludge. These polyesters were hydrolytically degraded to lower molecular weight compounds, and eventually to hydroxytetrahydropyran carboxylic acids, at different rates, depending on their molecular structure. Quantitative determination of carbon dioxide, generated during the treatment with the activated sludge, showed that the hydrolysates from polyesters 2 and 10, without pendant alkoxycarbonyl groups, were catabolized by microorganisms. It was concluded from these results that at least the polyesters without pendant groups were biodegradable, and that polyester 10, consisting of 2,6‐linked tetrahydropyran rings, underwent biodegradation more readily than polyester 2, consisting of 2,5‐linked tetrahydropyran rings. © 1994 John Wiley & Sons, Inc.
Phase equilibria in SBR/polybutadiene elastomer blends: Application of Flory–Huggins theory
Authors: Maier T. R. , Jamieson A. M. , Simha R. 
Published: April 2003

AbstractBlends of anionically‐polymerized polybutadiene (BR) and styrene–butadiene copolymer (SBR) must be treated as mixtures of terpolymers and tetrapolymers, due to the presence of three different BR isomers: cis‐1,4, trans‐1,4, and vinyl‐1,2. Moreover, in the absence of specific interactions or chemical reactions that strongly influence miscibility, structural characteristics of the component polymers, such as BR isomer content, SBR styrene content, monomer sequence distribution, molecular weight, and molecular weight distribution, are expected to have an increased role in determining the blend miscibility characteristics. Small angle neutron scattering (SANS) studies of SBR/BR blends have resulted in the computation of the monomer–monomer segmental interaction energetics via a Flory–Huggins treatment. This allows quantitative prediction of miscibility behavior as a function of polymer structure. We have used the Flory–Huggins chi parameters, describing the styrene/cis‐1,4, styrene/trans‐1,4, and cis‐1,4/trans‐1,4 segmental interactions, to identify certain blend combinations expected to exhibit phase transitions in an experimentally accessible temperature range. The appropriate polymers were synthesized, solution blended, and the blends analyzed via optical microscopy and thermal analysis. Our results show that the blend behavior, observed experimentally, is consistent with the calculated cloud point curves. © 1994 John Wiley & Sons, Inc.
Surface reactive acetal functional waterborne microparticles
Authors: Kjellqvist Kerstin , Rassing Jörgen , Wesslén Bengt 
Published: April 2003

AbstractSmall particles have been prepared by means of emulsion polymerization from styrene and ethyl acrylate, using different concentrations of emulsifier. The particle size can be controlled in the range of 45–85 nm. The particle surface was modified by introducing an acetal functionality, suitable for acid catalyzed processes. Surface functionalization was performed in two principally different ways. First, by using an acrylic monomer with acetal functionalities in the polymerization step and, second, by means of a surface grafting technique, using nonacrylic monomers. © 1994 John Wiley & Sons, Inc.
Desorption of residual monomer from PVC resins in a fluidized bed drier
Authors: Bouaffar H. , Yilmazer U. , Elbirli B. 
Published: April 2003

AbstractThe present study deals with the investigation of the desorption of vinyl chloride from various commercial and experimental suspension PVC resins in a laboratory fluidized bed drier simulating an industrial drier. The results show that PVC resins may differ widely in the rate at which the monomer is desorbed. The rate of diffusion of the monomer is a function of the drying time, the fluidization air temperature, the porosity, and the amount of glassy particles in the PVC. The residual monomer content decreases with increasing air temperature, drying time, and resin porosity. After 105 min of drying with hot air at 80°C, the residual monomer content in the grade with the highest porosity is reduced from 3400 to 2 ppm, whereas for the grade with the lowest porosity, it is reduced from 4300 to 172 ppm on a dry basis. It appears that the resins of the high molecular weight grades are more porous and the low molecular weight grades contain a high proportion of nonporous or glassy particles and, hence, the desorption rate is smaller in these grades. The proportion of glassy particles and the size of glassy domains are estimated in this study by applying the experimental desorption data at long times to a desorption model. The model is useful in differentiating the interior structure of various PVC grades. © 1994 John Wiley & Sons, Inc.
Magnetic field processing of polymers. I. Hydroxypropyl cellulose
Authors: Liepins Raimond , Jahn Randy K. , Elliott Norman E. , Hubbard Kevin M. 
Published: April 2003

AbstractHydroxypropyl cellulose (HPC) of degree of substitution three and average molecular weight of 100,000 was processed in a magnetic field of 1.2T. Films of HPC were cast from water, methanol, ethyl methyl ketone, and 1,1,2,2‐tetrachloroethane solutions in a magnetic field using static and dynamic casting techniques. The processed films were evaluated for tensile strength, elastic modulus, microhardness, and molecular chain alignment by wide angle x‐ray diffraction and polarized infrared. The best alignment and hence the greatest improvement in properties was obtained using a combined magnetic field and flow alignment procedure. These samples showed no increase in the elastic modulus, a 106% increase in the tensile strength, a 21% increase in the microhardness, and were dichroic. © 1994 John Wiley & Sons, Inc.This article is a US Government work and, as such, is in the public domain in the United States of America.
XPS study of dimethylolurea polymers and hollow fibers modified by these polymers. II. XPS study of hollow fibers modified by dimethylolurea polymers
Authors: Rouzies P. , Lebugle A. 
Published: April 2003

AbstractPolysulfone ultrafiltration hollow fibres are modified on the surface with polymers obtained by polycondensation of dimethylolurea (DMU). Depending upon the reaction conditions, polymers on the surface present a gel or a film form. In the first case the membranes are called “gel‐supported” and in the second case “coated”. Modified and unmodified polysulfone membranes were analysed by XPS spectroscopy. The modifications observed on a modified membrane were studied by reference to the previous article dealing with XPS analysis of gel and film DMU polymers. The study showed that gel‐supported membranes are modified by a polymer of a gel‐type chemical structure whereas coated membranes are modified by a polymer of film‐type chemical structure. The nature of the support, polysulfone, does not affect the final form of the polymer. © 1994 John Wiley & Sons, Inc.
Effect of chemical doping on the electrical conductivity of poly(2,6‐dimethyl‐1,4‐phenylene oxide)
Authors: Kalkar A. K. , Kundagol Shankar , Chand Suresh , Chandra Subhas 
Published: April 2003

AbstractThe electrical conductivity of solution‐grown poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) films doped with TCNQ, TCNE, TNF, and I2 has been studied as a function of dopant concentration, temperature (298–353 K), and field (50–2000 V). PPO forms a conductive complex on doping with these strong electron‐acceptor organic molecules. As with PPO, two distinct ohmic and nonohmic conduction regions at low and higher fields, respectively, are observed. The conduction properties of doped PPo films result from the formation of an isotropic continuous charge‐transfer complex. The existence of such a complex is confirmed by UV‐visible absorption spectra measurements. A possible mechanism for the electrical conduction process is discussed. © 1994 John Wiley & Sons, Inc.
Synthesis of NAD polystyrene microspheres and application as a carrier of glucoamyrase immobilization
Authors: Omi Shinzo , Kaneko Kazuyoshi , Takesue Mariko , Tsujimura Hamana , Satoh Atsunori , Iso Mamoru 
Published: April 2003

AbstractPolystyrene microspheres with a small amount of acrylic acid (200 : 1) incorporated were synthesized by nonaqueous phase dispersion (NAD) polymerization to investigate the feasibility of use as a carrier for immobilized enzyme. Seeded emulsion polymerization was then carried out to obtain larger cross‐linked polystyrene spheres, the structure of which was expected to yield a favorable environment to keep the original activity of the immobilized enzyme. Glucoamylase, a particular enzyme catalyzing the hydrolysis of oligosaccharides to glucose, was immobilized through peptide bonding using a carbodiimide activating agent. Thirty percent of the enzyme activity at maximum was retained relative to free glucoamylase. The immobilized enzyme remained active after 4 months, although its poor resistance to heat was not improved. © 1994 John Wiley & Sons, Inc.
Dissolution of perfluoroalkyl oligomers in lubricating oil for enhancing wear resistance and fuel economy
Authors: Derosa Thomas F. , Kaufman Benjamin J. , Sung Rodney L.‐D. , Russo Joseph M. 
Published: April 2003

AbstractPerfluorobutyl‐1,1,2‐tri‐H‐1‐hexene and perfluoroalkyl methacrylate have been solubilized in lubricating oil by single‐step free radically grafting onto poly(ethylene‐co‐propylene). Perfluoroalkyl‐1,1,2,2‐tetra‐H‐ethanol and perfluoropolyether carboxylic acid were solubilized by condensing with poly[(ethylene‐co‐propylene)‐g‐glycidyl methacrylate], generating the corresponding perfluoroalkyl ether or ester, respectively. Solubilization of 1,1,2,2‐tetra‐H‐ethanol was also achieved by condensing with poly[(ethylene‐co‐propylene)‐g‐2‐isocyanoethyl methacrylate] to the corresponding perfluoroalkyl urethane. Scar diameter reductions ranged from 9.4 to 58% using perfluoro‐modified graft copolymers as determined using the Four Ball Wear Test, although optimum reductions were obtained using perfluoroalkyl urethane‐modified graft copolymers. Moreover, a semiquantitative correlation of scar reductions and thermal instability was determined. Sequence VI engine testing of perfluoroalkyl urethane graft copolymers containing pendant perfluoroalkyl chain lengths of 8.2 and 7.2 had an Equivalent Fuel Economy Index of 4.33 and 4.27, respectively. © 1994 John Wiley & Sons, Inc.
Separability behavior in viscoelastic properties of EPDM gum vulcanizate
Authors: Namboodiri C. S. S. , Tripathy D. K. 
Published: April 2003

AbstractDynamic mechanical properties of EPDM gum vulcanizates were studied using the dynamic viscoelastometer, Rheovibron. A small sinusoidal strain was superimposed on a static strain and its effect on dynamic mechanical properties were analyzed. The results are discussed in terms of total strain which takes the static strain into account. Separability of time and strain effects for loss modulus and the nonseparability for storage modulus are discussed. A critical strain was identified after which the stress dissipation mechanism changes. © 1994 John Wiley & Sons, Inc.
Polysulfide sealant compositions. II. Interactions between elemental sulfur and organosulfur compounds
Authors: Hanhela Peter J. , Hook Robert J. , Paul D. Brenton 
Published: April 2003

AbstractAdded sulfur in polysulfide aircraft sealants can become chemically bound to the polymer backbone. The chemical processes involved, and their effect on thermal performance of the resulting sealants, have been examined. Reactions of aliphatic thiols with sulfur and amine catalysts have been reinterpreted to include possible involvement of hydropolysulfide intermediates. When the procedure was applied to polysulfide liquid polymers, products with substantial levels of tri‐ and tetra‐sulfide links were formed. 13C–NMR spectroscopy of model compounds enabled the assignment of chemical shifts associated with S3 to S5 links in the sulfur enriched polymers. Spectroscopic examination afforded no evidence for the presence of such species in commercial polysulfide liquid polymers.No obvious detrimental effects on elevated temperature performance of polysulfide sealants resulted from the incorporation of up to 1% sulfur into the polymer backbone. A higher degree of cure is achieved and this is associated with increased hardness and modulus, together with reduced extension as compared with untreated sealants. © 1994 John Wiley & Sons, Inc.
Thermal and crystallization behavior of engineering polyblends. II. Unfilled polyphenylene sulfide with poly(ethylene terephthalate)
Authors: Shingankuli V. L. , Jog J. P. , Nadkarni V. M. 
Published: April 2003

AbstractThe melting and crystallization behavior of blends of poly(phenylene sulfide) (PPS) with poly(ethylene terephthalate) (PET) has been investigated. The component polymers in the blend exhibited separate crystallization peaks and overlapping melting peaks. The nonisothermal DSC scans indicated that the crystallization parameters for PET become modified to a greater extent than do those for PPS in the blends. The PET crystallization peak became narrower with a higher heat of crystallization, suggesting a faster rate of crystallization as a result of blending with PPS. The isothermal crystallization studies revealed that the nucleation of PPS is facilitated by the presence of PET. This contention has been substantiated by polarized light microscopic observations. The spherulites of PPS were found to be smaller in the blends as compared to those in neat PPS. This enhancement in the nucleation of PPS has been attributed to the possibilities of chemical interactions between the component polymers. On the other hand, the increase in the rate of crystallization of PET has been attributed to the heterogeneous nucleation provided by the alreadycrystallized PPS. The melt crystallized blends exhibited slightly higher heats of fusion compared to the values computed from the rule of proportional additivity. © 1994 John Wiley & Sons, Inc.
Photoinduced graft copolymerization of 2‐hydroxyethyl methacrylate on cotton cellulose in the presence of triethyleneglycol dimethacrylate
Authors: Shukla S. R. , Athalye A. R. 
Published: April 2003

AbstractThe addition of a bifunctional monomer, triethylene glycol dimethacrylate (TEGDMA), to a grafting system containing 2‐hydroxyethyl methacrylate (HEMA) and benzoin ethyl ether photoinitiator substantially increased the graft add‐on of the unswollen and sodium hydroxide–swollen cotton cellulose. Grafting caused changes in the properties of the substrate such as moisture regain, the water of imbibition, and the dyeability with a direct and a reactive dye in accordance with the graft level. The observations have been explained in relation to structural changes in the grafted cotton. © 1994 John Wiley & Sons, Inc.
Deformation and fracture of PMMA at high rates of loading
Authors: Sahraoui S. , Lataillade J. L. 
Published: April 2003

AbstractThe scope of this article is to study the influence of loading rates on the deformation and the fracture of PMMA. The dynamic loading was achieved by means of an impact three point bend device for intermediate strain rates and by using a split Hopkinson's tensile bar apparatus for higher rates of loading. Tensile properties (Young modulus, yield stress) and fracture toughness are determined in a wide range of loading rates and compared to the literature results. Scanning electron micrographs of the tensile fracture surfaces are presented to illustrate the dynamic effect on the crack propagation. © 1994 John Wiley & Sons, Inc.
Sequence analysis of fluorine‐containing polyarylethersulfone copolymers by 13C–NMR
Authors: Wang Zhonggang , Chen Tianlu , Xu Jiping 
Published: April 2003

AbstractHexafluorobisA polyethersulfone‐cardo polyethersulfone, random and block copolymers with different segment lengths were synthesized by a reaction of 4,4′‐(hexafluoroisopropylidene) diphenol and 3,3′‐bis(4‐hydroxyphenyl)‐1‐isobenzopyrrolidone with bis (4‐chlorophenyl) sulfone. Their NOE‐suppressed quantitative 13C–NMR spectra were recorded on a 400 MHz NMR spectrometer. The 13C–NMR signals of tertiary carbon atom and quaternary carbon atom, on the benzene ring adjacent to sulfone group, appeared to be sensitive to sequence variation. Degrees of randomness of the copolyarylethersulfone synthesized were 0.96, closing to 1, and 0.39, as well as 0.55, far smaller than 1, indicating random distribution and regular distribution of the comonomers, respectively. The number average sequence length, calculated by 13C–NMR spectra, were shorter than expected, due to the transetherification reaction. © 1994 John Wiley & Sons, Inc.
Coemulsion and electrodeposition properties of mixtures of cationic epoxy resin and cationic acrylic resin containing blocked‐isocyanate groups
Authors: Chen Yahn‐Haur , Yang Chin‐Ping 
Published: April 2003

Abstract2‐Ethylhexanol–half‐blocked‐toluene diisocyanate (2EH‐half‐blocked TDI) was first reacted with 2‐hydroxyethyl methacrylate (HEMA) to prepare HEMA–TDI–2EH monomer containing blocked‐isocyanate groups. This monomer was reacted with butyl acrylate, styrene, and N,N‐dimethylaminoethyl methacrylate to prepare an acrylic copolymer III′ containing blocked‐isocyanate groups and tertiary amine groups. The acrylic copolymer III′ can be mixed with an epoxy–amine adduct IV′, acetic acid, and deionized (D.I.) water to from an electrodepositable coemulsion. The electrophoretic codeposition of the coemulsion and physical and chemical properties of the codeposited film were investigated. The resin composition of film deposited from coemulsion was determined by Fourier transform infrared (FTIR) quantitative analysis to study the coemulsion and electrophoretic codeposition behavior. The applicability of this two‐component coemulsion in primer–surface (pricer) electrodepositable paint was also discussed. The results indicate that the deposition yield of cationic acrylic copolymer III is greater than that of cationic epoxy resin IV, i.e., the deposition velocity of III is faster than that of IV. However, resins III and IV can be well codispersed in D.I. water to form stable coemulsion; thus, the resin composition of deposited is almost equal to the resin composition. Moreover, the throwing power of coemulsion is almost equal to that of IV emulsion but greater than that of III emulsion. The optimum resin compositions of coemulsions for obtaining better gel content of deposited films are between 0.65 and 0.8 (III/III+IV, by weight). © 1994 John Wiley & Sons, Inc.
Identification of fluorescent products produced by the thermal treatment of bisphenol‐A‐based polycarbonate
Authors: Rufus I. B. , Shah H. , Hoyle C. E. 
Published: April 2003

AbstractPolycarbonate is routinely subjected to heat treatment, and the thermal degradation products formed during this thermal treatment give rise to a distinct structured fluorescence spectrum. The structured fluorescence emission is observed when polycarbonate is subjected to thermal treatment in air as well as in nitrogen. A mixture of thermal rearrangement products of polycarbonate including dibenzofuran and phenyl‐2‐phenoxybenzoate are mainly responsible for the structured fluorescence emission. Most of the thermal degradation products of polycarbonate undergo photolysis, leading to the formation of photoproducts, which subsequently undergo a photoinduced bleaching process, with the noted exception of phenyl‐2‐phenoxybenzoate. The exposure of polycarbonate to high temperature for only short time periods, simulating mild industrial processing conditions, results in the formation of a relatively small amount of thermal degradation products, which, accordingly, has only a minor effect on the photodegradation of polycarbonate. © 1994 John Wiley & Sons, Inc.
Thermal, stability, morphological, and conductivity characteristics of polypyrrole prepared in aqueous medium
Authors: Biswas Mukul , Roy Anindita 
Published: April 2003

AbstractThe aqueous polymerization of pyrrole with varying FeCl3/Py mol ratio produces black insoluble powders. IR characterization reveals the shifting of the NH stretching band to higher frequency with increasing FeCl3 amount in the feed composition due to lowering of intermolecular H‐bonding. SEM shows a spongy texture of the polymer. TGA indicates the initial decomposition temperatures (180°–237°C) to be somewhat dependent on the FeCl3/Py feed ratio. DSC suggests the glass‐transition temperature to be in the range 160–170°C for the polymers prepared with various feed compositions. The conductivity is also dependent on the FeCl3/Py feed composition and levels off at a value of ∼3 ohm−1cm−1. © 1994 John Wiley & Sons, Inc.
The electrodeposition properties of coemulsion‐contained quaternary ammonium/tertiary amine salt epoxy–amine adducts and the composition analysis of its electrodeposited film
Authors: Yang Chin‐Ping , Ting Chih‐Yang 
Published: April 2003

AbstractTwo‐component electrodepositable coemulsion‐contained quaternary ammonium resin Q, as a pigment grinding vehicle, and DGEBA–N‐methylethanolamine (MEA) tertiary amine salt resin T, as the principal resin, were obtained and then deposited to form a resinous film on the cathode during electrodeposition. The resin composition of this deposited film was determined by the quantitative analysis of FTIR and it was found different from the resin composition of the original coemulsion. The electrodeposition behaviors of the coemulsion were deeply affected by the quaternary ammonium resin. In addition, the electrodeposition properties of emulsions dispersed by quaternary ammonium resin and tertiary amine salt resin were also studied for comparison. © 1994 John Wiley & Sons, Inc.
Heat pulse monitoring of curing and polymer–gas systems
Authors: Skripov Pavel V. , Puchinskis Stanislavs E. , Begishev Valerij P. , Lipchak Alexander I. , Pavlov Pavel A. 
Published: April 2003

AbstractAn implantable thermal probe is used to study the reaction of molten polymers and curing systems to pulse heat release. At the heating rates T˙≥5·105K/s, a polymer system shows the response to pulse heating that is confined in time and reproducible with respect to temperature. This response is related to the abrupt change in the conditions of the contact between the probe and a substance. The temperature of the response T* is determined by the polymer properties and depends on the pressure and T˙. The pulse thermal probe method, which includes two measuring procedures, complementing each other, has been used to monitor a number of processes in polymeric systems. The variation of the values of T* and the thermal activity of a polymer is compared with the variation of its molecular weight (M̄n∼ 102–106), the molecular weight distribution, and the concentration of a low molecular weight component. The method allows one to trace the kinetics of polymerization and curing and the kinetics of dissolution of volatile impurity and polymer devolatilization, and to determine the limit of supersaturation of gas solutions in molten polymers. The pulse repetition frequency is changed from 0.1 to 1 Hz. The heated volume of a substance is 10−4 mm3. © 1994 John Wiley & Sons, Inc.