bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gamma‐radiation induced grafting of acrylonitrile onto guar gum: Influence of reaction conditions on the properties of the grafted and saponified products
Authors: Lokhande H. T. , Varadarajan P. V. , Nachane Nayana D. 
Published: April 2003

AbstractIn the gamma‐radiation induced grafting of acrylonitrile onto guar gum, the influence of different concentration of the monomer acrylonitrile on the PAN add‐on, the number average molecular weight of the PAN side chains, and the grafting frequency of the PAN side chains are reported. At 0.3 Mard dosage, the PAN add‐on were 32.4, 48.5, and 66.2% and the number average molecular weight of the PAN side chains were 59,700, 132,200, and 238,900, respectively, at three different reaction conditions. The frequency of grafting also showed considerable variation at 0.2 Mrad dosage, for all three sets of samples. The viscosity of the aqueous dispersions of the saponified samples at different concentrations are also reported. The water absorbency of the saponified samples were evaluated and the values were around 250 g/g. The fall in viscosity of the aqueous dispersions on storage were also evaluated. The observed fall in viscosity was lower in the case of the product with higher PAN content. © 1993 John Wiley & Sons, Inc.
External lubrication of high‐temperature thermoplastic polymers
Authors: Stolarski T. A. 
Published: April 2003

AbstractExternal lubrication of high‐temperature thermoplastic polymers was studied experimentally. It was found that the nature of the lubrication fluid has a pronounced effect upon the behavior of the contact. It is postulated that premature failure of PEEK‐lubricated contacts is caused by the migration of linear carboxylic acids into the polymer matrix at elevated temperatures, thereby producing significant plasticization. A sequence of events leading to failure is given and some rationale for it provided. © 1993 John Wiley & Sons, Inc.
Low temperature slow rate penetration test: Evidence for its sensitivity to the thermomechanical relaxations in the case of ethylene–vinyl acetate copolymers
Authors: Porzucek K. , Lefebvre J. M. 
Published: April 2003

AbstractThe sensitivity of a low temperature slow rate penetration test to the dynamic mechanical response of ethylene‐vinyl acetate (EVA) copolymers with different compositions is clearly evidenced. The β‐molecular relaxation process occuring around −10°C controls the slow puncture behavior. The penetration resistance reaches a maximum value at this temperature and the type of rupture involved in the perforation mechanism varies on both sides of this critical temperature (brittle or ductile rupture). The parallel variations of the slow puncture resistance and of the high speed tensile impact strength with temperature, as well as with the vinyl acetate content, point to the reliability of the low temperature slow rate penetration test. This test thus appears as an efficient tool to simulate static mechanical deformations undergone by polymer films used in the sealed packaging of frozen food. © 1993 John Wiley & Sons, Inc.
Cross‐linking of bisepoxide with divalent metal salts of p‐aminobenzoic acid and diamine
Authors: Takechi Shigetoshi , Matsuda Hideaki 
Published: April 2003

AbstractCross‐linking of bisepoxide with divalent metal salts of p‐aminobenzoic acid and 4,4′‐diaminodiphenylmethane (4,4′‐methylenedianiline) was investigated. As the bisepoxide, bisphenol A diglycidyl ether was used. Mg and Ca were used as the divalent metal. The metal salts showed catalytic activities for the cross‐linking reaction and also for etherification of epoxy groups. In this case, the salt containing Ca with the lower electronegativity exhibited higher catalytic activities than that containing Mg. Hence, the cross‐linking reaction was supposed to proceed via an ionic mechanism. As for the physical properties of the cured resins, compressive strength was higher in the metal‐containing cured resins than in the resin without metal. Heat‐distortion temperature showed a tendency to decrease with increase in the metal content. However, glass transition temperature determined by dynamic mechanical properties were not influenced by the metal content. The metal‐containing cured resins exhibited low weight gain and changes in dimension and external appearance against boiling water. In addition, thermal decomposition was accelerated by the incorporated metal. © 1993 John Wiley & Sons, Inc.
Water‐soluble copolymers. XLV. Ampholytic terpolymers of acrylamide with sodium 3‐acrylamido‐3‐methylbutanoate and 2‐acrylamido‐2‐methylpropanetrimethylammonium chloride
Authors: McCormick Charles L. , Salazar Luis C. 
Published: April 2003

AbstractWater‐soluble, low charge density polyampholytes have been synthesized by free‐radical terpolymerization of acrylamide (AM) with sodium 3‐acrylamide‐3‐methylbutanoate (NaAMB) and 2‐acrylamido‐2‐methylpropanetrimethylammonium chloride (AMPTAC). Terpolymer compositions obtained by 13C‐NMR reflect monomer feed concentrations. Molecular weights and second virial coefficients range from 3.43 to 19.4 × 106g/mol and from 1.63 to 3.61 mL mol/g‐2, respectively, as determined by low‐angle laser light scattering. Ionic associations were explored by investigating the dilute solution properties as a function of terpolymer concentration, terpolymer charge density, and added electrolytes. Terpolymers with 0.5, 2.5, and 5.0 mol % of both of the cationic (AMTAC) and anionic (NaAMB) monomers were soluble in deionized water, whereas those with 10 and 15 mol % of each monomer required electrolyte addition. The higher‐density terpolymers undergo a 700% increase in intrinsic viscosity upon changing NaCl concentration from 0.05 to 1M. Polyelectrolyte behavior could be induced by decreasing solution pH below the pKa of the NaAMB mer. Intermolecular ionic associations resulting in gel networks were studied utilizing dynamic mechanical analysis. © 1993 John Wiley & Sons, Inc.
Efficiently activated carbon fiber derived from grafted novoloid fiber
Authors: Shimada Machiko , Takigami Shoji , Nakamura Yoshio , Abe Yukio , Iizuka Toshi , Makiyama Nobusuke 
Published: April 2003

AbstractGraft copolymerization of methyl methacrylate onto novoloid fiber was carried out by the electron beam mutual irradiation method. The characteristics of the grafted fiber were almost the same as those of the original novoloid fiber. The grafted fiber was carbonized and activated to yield an efficiently activated carbon fiber. The yield and the specific surface area of the activated carbon fiber, derived from the grafted novoloid fiber, were much greater than those derived from the original novoloid fiber. This is because grafted poly(methyl methacrylate) decomposes into monomer and gaseous products, forming pores on the surface and inside of the novoloid fiber on heating. © 1993 John Wiley & Sons, Inc.
Synthesis and characterization of polyester‐imides from imidodicarboxylic acid monomers and ethylene glycol
Authors: Kishanprasad V. S. , Gedam P. H. 
Published: April 2003

AbstractTwo monoimidodicarboxylic acids and four diimidodicarboxylic acids were synthesized from trimellitic anhydride and amino compounds, viz., glycine, p‐aminobenzoic acid, 4,4'‐diaminodiphenyl sulfide, 4,4'‐diaminodiphenyl ether, 4,4'‐diaminodiphenyl methane, and 4,4'‐diaminodiphenyl sulfide, and characterized by IR and 1H‐NMR spectroscopies and melting‐point determination. These functional monomers were condensed in N‐methyl‐2‐pyrrolidone solvent with ethylene glycol by a transesterification reaction to obtain the novel polyester‐imides with backbones of alternate imide‐ester linkages or imide‐imide‐ester‐ester linkages with SO2, O, CH2, or SS bridges in between. All the polymers were characterized by IR and 1H‐NMR spectroscopies, X‐ray diffraction, solution viscosity, solubility and solubility parameters, and differential thermal analysis. Most of the polymers possess amorphous structure and fairly high decomposition temperatures (450–485°C). These polymers having solubility parameters in the range δ 11.44–11.85, as determined by the group contribution technique, are soluble at room temperatures in aprotic polar solvents. © 1993 John Wiley & Sons, Inc.
Polymeric photoinitiators bearing side‐chain acyldiphenylphosphinoxide moieties for uv surface coatings
Authors: Angiolini Luigi , Caretti Daniele , Carlini Carlo , Lelli Nicola , Rolla Pier Angelo 
Published: April 2003

AbstractPolymeric photoinitiators bearing side‐chain acyldiphenylphosphinoxide moieties have been prepared by reacting poly(methacryloyl chloride) and methacryloyl chloride/methyl methacrylate copolymers with methoxydiphenylphosphine. The activity of the above polymeric systems has been checked in the UV curing of both clear and pigmented coating formulations and compared with that of the low molecular weight analog pivaloyldiphenyl‐phosphinoxide. The stability to light and to different hydrolitic conditions of the polymeric photoinitiators with respect to pivaloyldiphenylphosphinoxide has also been tested. The data concerning activity and stability are discussed in terms of structural features of the above systems. © 1993 John Wiley & Sons, Inc.
Investigations on vinylene carbonate. VI. Immobilization of alkaline phosphatase onto poly(vinylene carbonate) ‐jeffamine® hydrogel beads
Authors: Chen Guohua , Does Leen Van Der , Bantjes Adriaan 
Published: April 2003

AbstractHydrogel‐like polymers with reactive cyclic carbonate (CCA) groups have been obtained by the cross‐linking reaction of poly(vinylene carbonate) (PVCA) with Jeffamines®. By this reaction, microspheric hydrogel beads with a high water content and a high concentration of reactive CCA groups were prepared. The beads were used as a matrix for the immobilization of the enzyme alkaline phosphatase (ALP) and showed a considerable capacity to couple ALP and a reasonable retention of activity for the immobilized ALP, depending on the reaction conditions. The immobilized ALP exhibited a better thermal stability than did native ALP and a high residual activity was found after repeated use. © 1993 John Wiley & Sons, Inc.
Starch urea‐formaldehyde matrix encapsulation. IV. Influence of solubility and physical state of encapsulant on rate and mechanism of release
Authors: Shukla P. G. , Rajagopalan N. , Sivaram S. 
Published: April 2003

AbstractThe influence of the physical state and solubility of the encapsulant on the rate and mechanism of release and swelling of the cross‐linked starch‐urea formaldehyde (St‐UF) matrix has been studied by encapsulating model organic compounds. The release and swelling data have been analyzed in terms of the generalized equation Mt/M∞ = ktn applicable for swellable controlled‐release systems. This matrix system shows and an inverse relationship of release rate with the cross‐link ratio for all the encapsulants studied. The solid encapsulants have n values in the range of 0.22–0.41, indicating a Fickian or anomalous mechanism. Further, the release rate increases with solubility of the encapsulant. The liquid encapsulants have n values in the range of 0.5–1.5, indicating Case II transport mechanism. The release rates for liquid encapsulants are lower by one to three orders of magnitude than those for solid encapsulants and are not influenced by encapsulant solubility. This indicates a polymer chain relaxation‐controlled mechanism of release for liquid encapsulants. © 1993 John Wiley & Sons, Inc.
Radiation grafting of acrylic and methacrylic acids onto poly(tetrafluoroethylene‐hexafluoropropylene‐vinylidene fluoride) TFB films
Authors: Dessouki A. M. , Taher N. H. , El‐Arnaouty M. , Khalil F. H. 
Published: April 2003

AbstractA study has been made for the preparation of membranes by the direct radiation grafting of acrylic and methacrylic acids onto poly(tetrafluoroethylene‐hexafluoropropylene‐vinylidene fluoride) TFB films. The appropriate reaction conditions were selected under which the graft polymerization was carried out successfully. In this grafting system, ammonium ferrous sulfate (Mohr's salt), ferric chloride, and cuppric chloride were used as inhibitors to minimize the homopolymerization of acrylic acid and methacrylic acid. Also, the effect of monomer concentration on the rate of grafting was investigated. The dependence of the grafting rate on monomer concentration was found to be of the order of 1.1 and 1.0 for acrylic acid and methacrylic acid, respectively. This grafting system was proceeded by a front mechanism. Some selected properties of the grafted films such as swelling behavior, dimensional change, and mechanical and electrical properties were investigated. It was found that the grafted membranes possess good hydrophilic properties that may make them promising in some practical applications. © 1993 John Wiley & Sons, Inc.
Preparation of high molecular weight monodisperse polystyrene latexes by concentrated emulsion polymerization
Authors: Sun Fuming , Ruckenstein Eli 
Published: April 2003

AbstractThe preparation of high molecular weight monodisperse polystyrene (PS) latexes by the concentrated emulsion polymerization is investigated. The PS latexes thus obtained have diameters in the range of 0.1–0.3 μm. The average size and the dispersity of the latexes are dependent on the concentration of surfactant (SDS), the monomer volume fraction, and the amount of monpolymerizable additive (decane). The ionic strength does not seem to affect the size but affect the dispersity of the latexes. Under proper conditions, monodisperse particles can be prepared with a quite small standard deviation. © 1993 John Wiley & Sons, Inc.
Aqueous ring‐opening metathesis polymerization of exo‐7‐oxabicyclo [2.2.1] hept‐5‐ene‐2,3‐dicarboximide
Authors: Viswanathan Tito , Jethmalani Jagdish 
Published: April 2003

AbstractThe aqueous ring‐opening metathesis polymerization of the exo‐Diels‐Alder adduct of furan and maleimide was accomplished using an “activated Ruthenium” catalyst present in the supernatant of a RuCl3‐catalyzed aqueous polymerization of furan‐dimethylacetylene dicarboxylate adduct. The polymer was characterized by solution 1H− and 13C‐NMR, IR, DSC, and viscometry. Characterization revealed an intact imide group and the possibility of high‐temperature applications. © 1993 John Wiley & Sons, Inc.
The dependence of fracture properties on cure temperature in a DGEBA/DDS epoxy system
Authors: Min B.‐G. , Hodgkin J. H. , Stachurski Z. H. 
Published: April 2003

AbstractThe glass transition temperature (Tg), water‐ and solvent‐absorption characteristics, fracture toughness, and tensile properties of a diglycidyl ether of bisphenol‐A (DGEBA) ‐based epoxy resin (Epikote 8283) cured with an aromatic amine curing agent, 4,4' ‐diaminodiphenyl sulfone (DDS), were studied as a function of cure temperature and cure cycle (one‐step or two‐step cure). The glass transition temperature (which depends on the extent of cure) shows a linear increase with increasing cure temperature and levels off toward the cure temperature of 200°C. Water and solvent uptake tended to increase with increasing cure temperature and, hence, with cross‐linking level. Fracture toughness, tensile strength, strain to break, and tensile fracture energy also increased significantly with increasing final cure temperature regardless of cure cycle. In contrast, the small strain properties such as modulus, yield stress, and yield strain were not influenced greatly by cure temperature and cure cycle. From these results, we infer that the large strain properties of the resin are not inversely proportional to the cross‐link density of the network as reported in many publications, 1 but, rather, that they are dependent on other structural parameters such as free volume and the flexibility of the cross‐linked chains. © 1993 John Wiley & Sons, Inc.
Interrupted plasma treatment of EPDM‐40 rubber
Authors: Kondyurin A. V. 
Published: April 2003

AbstractThe glow discharge plasma treatment of EPDM‐40 rubber has been studied using the IRMATR spectroscopy. A mathematical model for the kinetics of rubber surface oxidation processes has been suggested. The interrupted plasma treatment was proposed as the most efficient technique of polymer surface activation. It was noted that the rubber oxidation processes occurs during the contact with air after the plasma treatment, but not during the discharge. © 1993 John Wiley & Sons, Inc.
Controlled antibody release from a matrix of poly(ethylene‐co‐vinyl acetate) fractionated with a supercritical fluid
Authors: Mark Saltzman W. , Sheppard Norman F. , Mchugh Mark A. , Dause Richard B. , Alan Pratt J. , Dodrill Amy M. 
Published: April 2003

AbstractA new method is presented for controlling the rate of antibody (Ab) release from an inert matrix composed of poly(ethylene‐co‐vinyl acetate) (EVAc), a biocompatible polymer that is frequently used to achieve controlled release. Using supercritical propane, a parent EVAc sample (Mn = 70 kDa, Mw/Mn = 2.4) was separated into narrow fractions with a range of molecular weights (8.7 < Mn < 165 kDa, 1.4 < Mw/Mn < 1.7). Solid particles of Ab were dispersed in matrices composed of different polymer fractions and the rate of Ab release into buffered saline was measured. The rate of Ab release from the EVAc matrix depended on molecular weight: > 90% of the incorporated Ab was released from low molecular weight fractions (Mn < 40 kDa) during the first 5 days of release, while < 10% was released from the high molecular weight fraction (Mn > 160 kDa) during 14 days of release. No significant differences in polymer composition, glass‐transition temperature, or crystallinity were identified in the different molecular weight fractions of EVAc. Mechanical properties of the polymer did depend on the molecular weight distribution, and correlated directly with Ab release rates. Because it permits rapid and reproducible fractionation of polymers, supercritical fluid extraction can be used to modify the performance of polymeric biomaterials. © 1993 John Wiley & Sons, Inc.
Preparation and characterization by thermal analysis of magnetic latex particles
Authors: Noguchi Hiromichi , Yanase Noriko , Uchida Yasuzo , Suzuta Tatsuo 
Published: April 2003

AbstractEmulsion polymerization of styrene and methyl methacrylate in the presence of a ferrofluid was briefly studied. Thermal properties of the resulted latex particles were investigated by TG–DTA analysis. Determination of the residue weight after the thermal analysis that indicated complete decomposition of the organic components was found to be a facile and practical method to determine the magnetite content in the latex particles. The method was applied to magnetic polystyrene latex particles prepared in the presence of various amounts of the ferrofluid. Analysis of the results suggested that the magnetic content in the latex particles is primarily determined by the weight ratio of the ferrofluid to monomer. © 1993 John Wiley & Sons, Inc.
Functionalized polysulfone membranes by heterogeneous lithiation
Authors: Guiver Michael D. , Black Paul , Tam Chung M. , Deslandes Yves 
Published: April 2003

AbstractPolysulfone membranes were modified heterogeneously by lithiation, using n‐butyllithium and low concentrations of tetrahydrofuran (THF). The effects of various conditions of reactant concentration, temperature, and time were determined quantitatively. The degree of substitution was measured by XPS and FTIR, using the carbonyl absorption band of lithium‐activated membranes that had been converted to ones containing acyl fluoride substituents. The optimum conditions for membrane functionalization were 0.2M n‐butyllithium in hexane at room temperature. The reaction rate increased substantially in the presence of 2% THF. The surface‐lithiated membranes can be derivatized, potentially with a wide variety of functional groups. © 1993 John Wiley & Sons, Inc.
The positive temperature coefficient phenomenon of vinyl polymer/CB composites
Authors: Tang Hao , Piao Jianhui , Chen Xinfang , Luo Yunxia , Li Shuhua 
Published: April 2003

AbstractIn this paper, the results of a systematic study of carbon black (CB)‐filled conducting polymer positive and negative temperature coefficient (PTC/NTC) effects are report. The conductivity of the composites jumps by several orders of magnitude at the critical value of carbon black. This critical value, øc, decreases with the increase of melt index and degree of crystallinity of the polymer. The crystalline lamellae just “modify” the distribution of carbon black and make the dispersion heterogeneous. Radiation cross‐linking enhances the PTC intensity and decreases the NTC effect of the materials. The electrical reproducibility of compounds is improved by the cross‐linking structure that reduces the freedom of carbon black movement at high temperature. The NTC phenomenon is related to the carbon black coagulation that facilitates electrical conduction at high temperature. The larger the melt index, the more easily carbon black coagulates. A new model was set up to explain the results successfully. © 1993 John Wiley & Sons, Inc.
Studies in the thermal degradation of poly(vinyl chloride)
Authors: Okieimen Felix E. , Ebhoaye Justus E. 
Published: April 2003

AbstractThermal degradation of poly(vinyl chloride) (PVC) was studied in nitrogen atmosphere in the presence of rubber seed oil and epoxidized rubber seed oil, barium and lead soaps of rubber seed oil, and epoxidized seed oil at various temperatures. The rate of dehydrochlorination at 1% degradation and the time required to attain 1% degradation were used to assess the effect of the thermal susceptibility of PVC to dehydrochlorination. It was found that epoxidized rubber seed oil, the metal soaps of rubber seed oil, and epoxidized rubber seed oil markedly enhance the thermal stability of PVC. The order of increasing stabilizing influence was metal soaps of epoxidized rubber seed oil > metal soaps of rubber seed oil > epoxidized rubber seed oil > rubber seed oil. © 1993 John Wiley & Sons, Inc.
COR‐eos and BH‐eos parameters for polymer melts with the error in the all‐variables method
Authors: Wohlfarth Christian 
Published: April 2003

AbstractAll the data for more than 100 polymer melts in a PVT data base were used to determine best‐fit characteristic parameters for two different theoretical equations‐of‐state (eos): the chain‐of‐rotators (COR) and the Bruce Hartmann (BH) eos. Fitting was performed by applying an error in all‐variables algorithm that was recently developed by Hartmann etal. Despite their very different theoretical basis, both equations‐of‐state led to close descriptions of the PVT surface with comparable average deviations. © 1993 John Wiley & Sons, Inc.
Nucleation and crystal growth of PEEK on carbon fiber
Authors: Zhang Zhiyi , Zeng Hanmin 
Published: April 2003

AbstractThe necleation and crystal growth of poly(ether ether ketone) (PEEK) on carbon fiber during isothermal crystallization were studied using optical microscopy. It was shown that the nucleation rate on the fiber is affected by the crystallization and melting temperatures. Transcrystallinity of PEEK was found to appear in the range 280–315°C after PEEK was melted at rather high temperature. Its linear growth rates at various temperatures were found to be similar to those of the spherulite in the bulk. Also, its thickness depends on the crystallization and melting temperatures. Variation of the molecular weight of PEEK within a small range has no obvious influence on its nucleation rate on the fiber, but affects the transcrystalline growth rate. © 1993 John Wiley & Sons, Inc.