bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation of new hydrophilic and durable porous polymer particles
Authors: Terauchi Ken‐Ichi 
Published: April 2003

AbstractA preparation method for new highly durable hydrophilic porous polymer particles consisting of acrylic monomers and copolymerizable cross‐linking agents was studied. In the case of using only a two‐functional acrylic monomer as the cross‐linking agents, the obtained particles had a relatively low mechanical strength, but by the addition of a multifunctional acrylic monomer into the above system, it was found that the porous particles obtained became highly durable and showed excellent mechanical strength of more than 500 kg/cm2. The effect of preparation conditions on the specific surface area of these particles consisting of three components was investigated from the following viewpoints: The first was aimed at the stabilized phase of droplets consisting of monomer/cross‐linkers/porogen under various conditions of aqueous poly(vinyl alcohol) (PVA) media, and the second was the effect of composition changes of the monomer and cross‐linkers on the inner porous structure of the particles obtained. Thus, the specific surface area of the particles was found to be significantly affected both by the degree of saponification (DS) of PVA and by the change of composition. On the other hand, the average pore radius of typical particles obtained in this way can be controlled in the range from 40 to 120 Å by the weight ratio of chlorobenzene as the porogen. Furthermore, the mechanical stability and durability of the column packed with the porous particles obtained were discussed. © 1993 John Wiley & Sons, Inc.
Study on physical properties of poly(vinyl acetate) emulsion films obtained in batchwise and in semicontinuous systems
Authors: Okaya Takuji , Tanaka Taku , Yuki Ken 
Published: April 2003

AbstractEmulsion polymerization of vinyl acetate was carried out batchwisely or semicontinuously in the presence of a nonionic surfactant or poly(vinyl alcohol) (PVA). From the investigation of degrees of polymerization of poly(vinyl acetate) (PVAc) during the course of polymerization and those of corresponding hydrolyzed PVA, it was clarified that the degrees of polymerization of the batchwise system are much larger than those of the semicontinuous system, and long branches and shorter branches are formed in the batchwise and the semicontinuous systems, respectively. The emulsion films obtained batchwisely had properties with better tensile strengths by two to four times (nonionic system) and 1.5 times (PVA system) than those obtained semicontinuously. The former films revealed a better water‐resistant nature compared with the latter films. © 1993 John Wiley & Sons, Inc.
Preparation and application of low molecular weight poly(vinyl chloride). III. Mechanical properties of blended poly(vinyl chloride)
Authors: Yamamoto Kikuo , Maehala Takashi , Mitani Katsuo , Mizutani Yukio 
Published: April 2003

AbstractThe blending effect of poly(vinyl chloride) with relatively higher molecular weight (HMW‐PVC) and relatively lower molecular weight (LMW‐PVC) has been investigated by measuring various mechanical properties: melt properties, tensile strength, tensile modulus, and impact strength. The blended PVC has slightly improved melt properties in comparison with the HMW‐PVC used. The tensile strength of the blended PVC is related to the weight‐average polymerization degree (Pω) of LMW‐PVC and the LMW‐PVC content. At the LMW‐PVC content of 20%, the tensile strength of blended PVC is a maximum: approximately 58 MPa. © 1993 John Wiley & Sons, Inc.
Polyester‐modified poly(ethylene ether carbonate) polyols by molecular weight advancement
Authors: Harris Robert F. 
Published: April 2003

AbstractPoly(ethylene ether carbonate) polyols can be modified by chemical reactions with polyester polyols, poly(carboxylic acids), poly(carboxylic acid) esters, or poly(carboxylic acid) cyclic anhydrides under conditions of elevated temperatures and reduced pressures to give estermodified poly(ethylene ether carbonate) polyols. Polyester polyols and poly(carboxylic acid) ester are incorporated into the polymer backbone by transesterification/ advancement reactions. Poly(carboxylic acids) and poly(carboxylic acid) cyclic anhydrides first undergo esterification and then transesterification / advancement reactions. Molecular weight builds in a predictable manner and can be controlled by the amount of distillate removed. The processes have been characterized by following the distillate formation and composition as a function of reactor temperature and product molecular weight build. The products have been characterized by molecular weight and carbon‐13 NMR spectroscopy. A new family of ester‐modified poly(ethylene ether carbonate) polyols has been prepared, most of which were not available with prior technology. These polyols are useful in polyurethane applications, where the degree and type of poly modification can be used to adjust polyurethane properties. © 1993 John Wiley & Sons, Inc.
Novel cycloaliphatic epoxy resins. II. Curing reaction with BF3MEA and its cured properties
Authors: Tokizawa Makoto , Okada Hiroyoshi , Wakabayashi Nobukatsu 
Published: April 2003

AbstractThe BF3MEA curing reaction and the cured properties of novel cycloaliphatic epoxy resins (CE‐resins), which were derived from an octadienyl compound, were studied. Gelation time and the DSC scan of the CE resins, with BF3MEA hardener, proved that the reactivity of the CE resins is intermediate among the reactivities of the conventional resins; it was found that the CE resins react faster than DGEBA, but slower than the conventional cycloaliphatic epoxy resins. The pot life of the CE‐ (III) resin with BF3MEA hardener proved to be over 30 days at a temperature of 20°C. The thermal properties are affected by the amount of BF3MEA used and the curing conditions. CE‐(III) showed the highest HDT of over 200°C with 2–3 phr of BF3MEA. The flexural properties of CE‐(I) proved to be flexible and tough. CE‐(II) exhibited the highest strength and elongation, while CE‐(III) had the same flexural properties as DGEBA. Furthermore, the blending of CE‐(II) with DGEBA produced greater flexural strength and greater elongation than each original resin had. The thermal stability at elevated temperature and the water resistance of the cured CE resins proved to be inferior to those of DGEBA and novolac epoxy resin, probably due to the use of BF3MEA. These results suggest the CE resin will provide a new application for a one‐component curing system for composites. © 1993 John Wiley & Sons, Inc.
Dynamic rheological studies of hydrophobic interactions in injectable collagen biomaterials
Authors: Rosenblatt Joel , Devereux Brian , Wallace Donald G. 
Published: April 2003

AbstractInjectable collagen is a concentrated dispersion of collagen fibers in aqueous solution that is used to correct dermal contour defects through intradermal injection. The effect of hydrophobic forces on the rheology of concentrated dispersions of collagen fibers was studied by dynamic rheological measurements over temperatures ranging from 283 to 308 K. The results are interpreted in terms of the associated relaxation time spectra and the theory of Kamphuis et al. for concentrated dispersions. Increases in fiber rigidity are seen from a progressive decrease in the slope of the linear log G′ (or G″) vs. log ω data recorded for these dispersions as temperature is increased. A molecular interpretation of this result was obtained by treating collagen fibers as a liquid crystalline phase of rigid‐rod collagen molecules that have phase‐separated from aqueous solution. Hydrophobic forces affect the volume fraction of water that is present in the phase‐separated fibers, which, in turn, affects the rigidity of the fibers. Distinct yielding behavior (in the nonlinear viscoelastic region) occurs at temperatures above 293 K and reflects a gel transition. Thermal gelation of collagen dispersions is proposed to proceed through hydrophobically driven mechanisms of increased fiber rigidity and enhanced interfiber attractive forces. © 1993 John Wiley & Sons, Inc.
Synthesis and characterization of amide linkage‐incorporated polyethyleneimine‐based chelating resins and studies of the crosslink density and surface properties on metal ion uptake
Authors: Thiagarajan N. , Subbaiyan M. 
Published: April 2003

AbstractThe chelating resins incorporating amide linkages were synthesized in open reaction vessels (OV) by polycondensing different proportions, viz., 1 : 1, 1 : 1.3, and 1.3 : 1 of polyethyleneimine (PEI) and diethylenetriaminepentaacetic acid (DTPA), respectively, at 145–155°C, and at varying curing times (15 h and 22 h). For the proportion 1 : 1, the synthesis was performed in a closed reaction vessel (CV) as well. The resins were characterized by FTIR, elemental, and thermogravimetric analysis, apart from sarptometric surface studies. The extent of crosslinking was evaluated by swelling measurements and the chemical stability was assessed by acid and alkali treatment. The effect of the mode of heating and curing times on the extent of crosslinking and pore structure modifications were evaluated. The influence of these factors on the capacities, the kinetics, and the break through curve trends of these resins were studied using zinc and cadmium metal ions as references. The reproducibility of the resins were ascertained by assessing the extent of change in the break through curve trends of their different batches, synthesized under identical conditions. © 1993 John Wiley & Sons, Inc.
Surface and interfacial FT–IR spectroscopic studies of latexes. VIII. The effect of particle and copolymer composition on surfactant exudation in styrene‐n‐butyl acrylate copolymer latex films
Authors: Kunkel Jeremy P. , Urban Marek W. 
Published: April 2003

AbstractPolarized attenuated total reflection Fourier transform infrared (ATR FT–IR) spectroscopy was used to identify the mobility and surfactant exudation of sodium dioctyl sulfocuccinate (SDOSS) surfactant molecules to the film–air (F–A) and film–substrate (F–S) interfaces in styrene/n‐butyl acrylate (Sty/n‐BA) latex films. It was found that, depending upon the latex particle composition, the surfactant molecules could be driven to the F–A or F–S interfaces. The primary factors that governed the direction of exudation were the compatibility of the latex components, interfacial film‐substrate surface tension, and the chemical composition of the latex particles. Concentration, as well as orientation, of the hydrophilic SONa+ surfactant ends changed as a function of depth and the latex particle composition. © 1993 John Wiley & Sons, Inc.
Heat treatment studies of a TLCP fiber
Authors: Sarlin Juha , TörmäLä Pertti 
Published: April 2003

AbstractThis work deals with the heat treatment of fibers and nonoriented specimens made of the thermotropic liquid crystalline polymer Vectra A900 in the light of tensile properties and DSC measurements. In calorimetric measurements, there seem to be some differences in the effects of the treatment between macroscopically isotropic (nonoriented) and highly oriented fiber specimens. Nonisothermal treatments also produce some effects on the tensile properties, which may be attributable to the thermal history of samples. Under the conditions of this study, a multistep treatment, ending at a final stage where the temperature was higher than the original melting point of the polymer, did not cause any acceleration in the rate at which tensile properties increase. © 1993 John Wiley & Sons, Inc.
Finite element model and experimental analysis of crack–inclusion interaction
Authors: Li R. , Wu S. , Ivanova E. , Chudnovsky A. , Sehanobish K. , Bosnyak C. P. 
Published: April 2003

AbstractOne of the key requirements for developing tough multiphase blend systems, for example, selecting the type of discrete phases (hard or soft) in a polymer matrix, is the ability to predict the fracture path. Most of these selections rely heavily on prior experience or on intuitive rationale. There are few mathematical guidelines for the materials scientists who are designing new multiphase systems. This article is designed mainly to provide such insight through the development of a theoretical model and through experimental observation. A finite element model has been used to predict the crack velocity and the crack path for a crack that approaches and penetrates a hard or a soft inclusion. A novel experimental approach is then utilized to verify these predictions by introducing hard and soft circular domains in poly(ethylene‐co‐carbon monoxide) specimens by selective photodegradation. © 1993 John Wiley & Sons, Inc.
Optical absorption and thermally stimulated depolarization current studies of nickel chloride‐doped poly(vinyl alcohol) irradiated with low‐level fast neutron doses
Authors: El‐Kader F. H. Abd , Attia G. , Ibrahim S. S. 
Published: April 2003

AbstractThe influence of neutron irradiation on ultraviolet/visible absorption and thermally stimulated depolarization current in nickel chloride–poly(vinyl alcohol) (PVA) cast films has been investigated. The spectral measurements indicate the responsibility of the Ni2+ ion in its octahedral symmetry. Dopant concentrations higher than 10 wt % Ni Cl2 are found to make the samples more resistant to a degradation effect caused by neutron irradiation. The thermally stimulated depolarization currents (TSDC) of pure PVA revealed the existence of the glass transition Tg and space charge relaxation peaks, whereas doped‐PVA samples show a new sub‐Tg relaxation peak. A proposed mechanism is introduced to account for the neutron effects on both glass transition and space charge relaxation peaks. The peak positions, peak currents, and stored charges of the sub‐Tg relaxation peak are strongly affected by both the concentration of the dopant and neutron exposure doses. © 1993 John Wiley & Sons, Inc.
An XPS study of different polyvinylalcohol films' surface composition
Authors: Chihani Thami , Hjertberg Thomas 
Published: April 2003

AbstractDifferences in surface chemical composition were found when examining poly(vinylacetate‐co‐vinylalcohol) (PVOH) film surfaces. The content of the acetate groups increased at the outermost surface when dried in air and similar content, when dried against a glass surface, compared to the bulk content. The enrichment varied from 200–1300%, as compared to the bulk content. The enrichment of the acetate groups was studied with X‐ray photo electron spectrocopy (XPS or ESCA) at different analyzing angles. The bulk content was measured with Nuclear Magnetic Resonance spectrometry (NMR). © 1993 John Wiley & Sons, Inc.
Polymerization studies: The application of differential thermogravimetric analysis
Authors: Popović Ivanka G. , Katsikas Lynne , Weller Horst , Schrötter Susanne , Veliĉkoví Jovan S. 
Published: April 2003

AbstractThe application of differential thermogravimetric analysis (DTGA) to the study of polymerization mechanisms is illustrated using as examples the radical polymerization of di‐n‐alkyl itaconates and methyl methacrylate (MMA). Five poly(di‐n‐alkyl itaconates) were prepared in bulk, both in the presence and absence of n‐dodecyl mercaptan and in solution using AIBN as initiator. The poly(methyl methacrylate) (PMMA) was photoinitiated using colloidal CdS as a photosensitizer. The thermal properties of the resulting polymers are described in terms of the proposed polymerization mechanisms. The advantages and disadvantages of DTGA for the identification of thermally weak structures are discussed. © 1993 John Wiley & Sons, Inc.
Photoluminescence study of β relaxation of polyethylene blends
Authors: Martins‐Franchetti S. M. , Atvars T. D. Z. 
Published: April 2003

AbstractSecondary β relaxation of polyethylene blends (50/50 HDPE/LDPE) were studied by photoluminescence of anthracene molecules dissolved in the polymer bulk. The temperature of the β relaxation has been determined as Tβ = −40°C by the dependence of the ratio of vibronic components of the fluorescence band on the temperature. The molecular mechanism of this relaxation has been discussed considering the possibility of the energy migration involving anthracene molecules in the singlet electronic excited and ground states. © 1993 John Wiley & Sons, Inc.
Allylamine‐adducted bismaleimide resins. I. The curing reactions
Authors: Lin King‐Fu , Lin Jin‐Sing 
Published: April 2003

AbstractA variety of allylamine‐adducted bismaleimide (A‐BMI) resins were prepared by reacting bismaleimide (BMI), such as 4,4′‐bismaleimidodiphenylmethane (BDM) and 4,4′‐bismaleimidodiphenylether (BDE), with various molar ratio of allylamine through the Michael addition. The prepared A‐BMI resins are a partial crystalline or completely amorphous solid, depending on the amount of adducted allylamine. Two types of curing reactions for the A‐BMI resins were detected by differential scanning calormetry and verified by the mass spectroscopies of cured resins: one is the homopolymerization of A‐BMI resins through opening of the double bonds in the maleimide groups; the other is the reactions between allyl groups and benzene rings, taking place mainly when most of the double bonds in maleimide groups of the A‐BMI resins have been opened by allylamines. © 1993 John Wiley & Sons, Inc.
Effects of fluorinated substituents on the refractive index and optical radiation resistance of methacrylates
Authors: Gaynor Justin , Schueneman Gregory , Schuman Paul , Harmon Julie P. 
Published: April 2003

AbstractNovel fluorinated methacrylate polymers were synthesized. The purpose was to produce polymers with low refractive indices and increased resistance to optical radiation damage. Six different fluorinated substituents were appended on the monomer before polymerization. Optical‐quality samples were prepared, and their transmission spectra, through 0.8 cm thick samples, were obtained. Each sample was tested for refractive index and glass transition temperature. The samples absorbed 10 MRad gamma radiation from a 60Co source in an air environment; their transmission spectra were recorded immediately after irradiation and again after seven days had elapsed. As expected, increasing the fluorine content in the side chains resulted in decreased refractive indices. Fluorine content also influenced optical radiation stability. One polymer, poly(1H,1H‐heptafluorobutyl methacrylate) retained superior UV/visible transmission after irradiation. © 1993 John Wiley & Sons, Inc.
Comparative study of unsaturated halo and nonhalo polyesters and inhibition of double‐base rocket propellants
Authors: Agrawal J. P. , Kulkarni K. S. 
Published: April 2003

AbstractUnsaturated halo and nonhalo polyesters, based on tetrachlorophthalic anhydride, tetrabromophthalic anhydride, and phthalic anhydride with diethylene glycol and maleic anhydride, have been synthesized, using a “2‐step” polyesterification process. These were mixed with 35% styrene monomer and 0.02% hydroquinone. The structural aspects of halo and nonhalo polyesters have been studied by IR and NMR. Further, these polyesters have been characterized for various properties. A comparison of various properties suggests that tensile strength, bond strength, heat resistance, flame retardance, gel time, and oxygen index follow the order as BP‐35 > CP‐35 > NHP‐35, whereas the order for other properties, such as exotherm peak temperature, thermal conductivity, % elongation, and nitroglycerine absorption, is BP‐35 < CP‐35 < NHP‐35. Variation in the properties of cured halo and nonhalo polyesters has been discussed in terms of structural considerations. The nature of P‐t profile of inhibited double‐base (DB) rocket propellants on static evaluation suggests that CP‐35 is a potential inhibitor for DB propellants. © 1993 John Wiley & Sons, Inc.
Adiabatic anionic polymerization of caprolactam in the presence of N‐acylated caprolactam macroactivator: Kinetic study
Authors: Yeh Jen‐Long , Kuo Jen‐Feng , Chen Chuh‐Yung 
Published: April 2003

AbstractIn this study, bis ϵ‐caprolactam bis‐diphenyl methane diisocyanate polypropylene glycol 1000 used as the macroactivator was prepared and well characterized prior to use. The anionic polymerization of ϵ‐caprolactam with the macroactivator as a function of the macroactivator concentration was adiabatically carried out. The adiabatic temperature rise method as well as the macrokinetics were used for elucidation of the kinetics of the polymerization. A nonlinear regression technique was used for determining the parameters of the macrokinetic equation. The equilibrium conversion and equilibrium time obtained were 94–96% and 2–9 min depending on the macroactivator concentration. The effects of the concentrations of macroactivator and ϵ‐caprolactam on the initial rate, apparent overall reaction rate, and the empirical parameters were studied. A side reaction induced by the transfer of the proton in the isocyanurate group of the macroactivator to caprolactam anion was found. According to this finding, a new reaction kinetic model was proposed by properly modifying the macrokinetic equation. © 1993 John Wiley & Sons, Inc.
Cathodic delaminations of poly(phenyl ether ether ketone) (PEEK) coatings overlaid on zinc phosphate‐deposited steels
Authors: Sugama T. , Carciello N. R. 
Published: April 2003

AbstractThe melt‐crystallized poly(phenyl ether ether ketone) (PEEK) polymer was overlaid on crystalline zinc phosphate (Zn • Ph) conversion coating‐deposited and nondeposited coldrolled steels at 400°C in air or in N2 environments. The ability of these coating systems to protect the steel against corrosion was evaluated from the rate of cathodic delamination of the coating layer from the steel. Because the cathodic reaction, H2O + 1/2O2 + 2e− = 2OH−, at the corrosion side of a defect in the coating layer creates a high pH environment at the interfacial boundary between the coating and steel, the magnitude of susceptibility of the interfacial intermediate layers to the alkali‐induced degradation played a key role in suppressing cathodic failure. The lowest level was observed in the N2‐induced PEEK/Zn • Ph/steel joint systems, thereby decreasing the rate of delamination. By contrast, oxidized PEEK induced by air in same joint systems was susceptible to the alkali‐catalyzed hydrolysis. This phenomenon significantly promoted the alkali dissolution of Zn • Ph crystals, reflecting a high rate of delamination. Nevertheless, the introduction of Zn • Ph as interfacial tailoring material into the intermediate layers markedly acted in reducing the cathodic delamination of PEEK/steel joint systems. © 1993 John Wiley & Sons, Inc.
Study of the electric‐field effect in polyethylene by the positron annihilation technique
Authors: El‐Sayed A. M. A. , Abdel‐Hady E. E. , Mohsen M. 
Published: April 2003

AbstractThe positronium formation and the reversibility behavior of the electric field from 31.75 to 588.24 kV/cm were studied in high‐density polyethylene (HDPE) using the positron annihilation lifetime technique. The lifetime measurements were performed using the conventional fast‐fast coincidence timing system. The observed ortho‐positronium life time τ3 does not show significant variation from the corresponding values measured without the electric field. On the other hand, the corresponding intensity I3 increases with increasing the electric field strength in the range from ∼ 100 to 588.24 kV/cm. This result indicates a strong irreversible effect of the electric field. In addition, the effect of temperature on the sample stressed at 450 kV/cm was investigated. The structural changes on the heating and cooling cycles show reversible behavior. The thermal expansion coefficient has been deduced to be 7.53 × 10−3/°C. © 1993 John Wiley & Sons, Inc.