bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and polymerizations of monomers bearing phosphonated groups. I. Applications on acrylates and methacrylates
Authors: Boutevin B. , Hamoui B. , Parisi J. P. 
Published: April 2003

AbstractThe synthesis of (meth)acrylic monomer bearing phosphonic esters, phosphonic acids, and semisalts is presented. This synthesis was performed in four steps. The first concerns the phosphonylation of allyl bromide by Arbuzov reaction. Second is the monoaddition of 2‐mercapto ethanol onto the allyl double bond, whereas the third consists of the acrylation of the previous phosphonated alcohol. The fourth step involves the dealkylation of the phosphonated ester by the mean of trimethyl halosilane and then the hydrolysis of the obtained silyl ester. Finally, the salification of the diacid is performed in order to stabilize the diacid. In the last part of this work two applications of these monomers in the field of additives for adhesives cured by UV or EB were studied. The results clearly show the superiority of phosphonic acid about the homologous esters. Moreover, the number of acid group and the neighbouring of this acid play an important part in adhesion phenomenon. © 1994 John Wiley & Sons, Inc.
Analysis on the surface adsorption of PEO/PPO/PEO triblock copolymers by radiolabelling and fluorescence techniques
Authors: Amiji Mansoor M. , Park Kinam 
Published: April 2003

AbstractWe have examined the adsorption of poly(ethylene oxide)/ poly(propylene oxide)/poly(ethylene oxide) (PEO/PPO/PEO) triblock copolymers (Pluronics™) on dimethyldichlorosilane‐treated glass (DDS‐glass). The surface concentration of 125I‐labeled Pluronic F‐68(76/30/76) reached a maximum of 0.3 μg/cm2 when the bulk concentration in the adsorption solution was 3.0 mg/mL. Above 5.0 mg/ml, the surface Pluronic F‐68 concentration started to decrease and reached 0.17 μg/cm2 when the bulk concentration for adsorption was 10 mg/mL. The surface concentration of Pluronic F‐108 (129/56/129), on the other hand, increased to 4.0 μg/cm2 at the same bulk concentration. Fluroscence spectroscopic studies using pyrene suggested that the Pluronic F‐68 molecules self‐associated at the bulk concentration of 5.0 mg/mL and above. Because the aggregates are expected to expose the hydrophilic PEO segments to water, they may have lower affinity to DDS‐glass. Aggregation of Pluronic F‐68 also decreases the number of individual Pluronic molecules for adsorption. Pyrene fluorescence in Pluronic F‐108 solution, however, suggests that Pluronic F‐108 molecules do not form aggregates. It appears that the high surface concentrations of Pluronic F‐108 may result from the preferential adsorption of individual molecules in multilayers. This explains the high effectiveness of Pluronic F‐108 in preventing protein adsorption and platelet adhesion when adsorbed on to be hydrophobic surface. © 1994 John Wiley & Sons, Inc.
Chemical structure and physical properties of antheraea assama silk
Authors: Freddi Giuliano , Gotoh Yoko , Mori Tadasu , Tsutsui Ichihiko , Tsukada Masuhiro 
Published: April 2003

AbstractThis work deals with the chemical composition, physical structure, and thermal behavior of Antheraea assama silk fibers. The amino acid composition is characterized by the high content of alanine, glycine, and serine. Among the amino acid residues with polar side chains, aspartic acid, arginine, and tyrosine prevail. The birefrigence and isotropic refractive index values are 0.030 and 1.557, respectively. The stress‐strain curve shows a yield point at 5% elongation, followed by a region of gradual extensibility. Blongation at break is about 40%. The X‐ray diffraction pattern is typical of β silks, with–(ala)n–repeats in the polypeptide sequences of the crystalline regions. The differential scanning calorimetry curve shows two minor endotherms at 230 and 300°C, before final thermal decomposition at 362°C. The maximum extent of contraction exhibited by the thermomechanical analysis curve is 2%. The surface of degummed fibers shows the presence of longtitudinal strations. The fiber cross section is mostly relliptical. Raw Fibers taken from cocoons show the presence of several crystalline deposits on the surface, identified as crystals of calcium oxalate. © 1994 John Wiley & Sons, Inc.
Cyclotrimerization of isocyanate groups. I. Catalyzed reactions of phenyl isocyanate
Authors: S̆pírková Milena , Kubín Miroslav , S̆pac̆ek Pavel , Krakovský Ivan , Dus̆ek Karel 
Published: April 2003

AbstractCyclotrimerization of phenyl isocyanate in the presence of various catalysts was studied. All reactions were carried out in 1,4‐dioxane at 30–50°C. Reaction products were determined by reverse‐phase liquid chromatography. 1,3,5‐Triphenyl isocyanurate was formed and also traces of 1,3‐diphenylurea and 1,3,5‐triphenylbiuret were found. The catalytic activity decreased in the following series: quaternary ammonium salt > organic acid salt ≫ tertiary amine. Apparent rate constants of cyclotrimerization were calculated and the overall reaction order is discussed. © 1994 John Wiley & Sons, Inc.
Influence of the controlled rheology process (vis‐breaking) on additive effectiveness in polypropylene
Authors: Tollefson Norris M. 
Published: April 2003

AbstractControlled rheology or VIS‐breaking is the process whereby polypropylene, peroxide, and other additives such as stabilizers are extruded to simultaneously shorten polymer chain length by chemical action of the peroxide and to blend in additives. Although the influence of additives on the VIS‐breaking process has been studied, little attention has been paid to the role of additives present during VIS‐breaking on the final resin properties. The effectiveness of a light mineral oil used as a costabilizer for radiation resistance and Irgafos 168 as a melt stabilizer was determined in polypropylene resins prepared with different peroxide levels. It was found that exposure of Irgafos 168 to peroxide during the VIS‐breaking process did not hinder the action of Irgafos 168 as a melt stabilizer during injection molding. At low levels of peroxide, the presence of oil led to an improvement of radiation resistance compared to resins that contained no oil. However, at higher peroxide levels, oil‐containing resins showed less resistance to radiation than did those without oil. These results were interpreted as an interaction of peroxide with the function of oil in the final resins. © 1994 John Wiley & Sons, Inc.
Mechanical properties of the rubber‐toughened polymer blends of polycarbonate (PC) and poly(ethylene terephthalate) (PET)
Authors: Liao Zhi‐Li , Chang Feng‐Chih 
Published: April 2003

AbstractThe intrinsically impact‐brittle PC/PET blends can be effectively toughened, in terms of lower ductile brittle transition temperature (DBTT) and reduced notch sensitivity, by incorporating butylacrylate core‐shell rubber. The rubber particles are distributed exclusively in the PC phase. Varying the PC melt flow rate (MFR) is more important than varying the PET I.V. to vary the low temperature toughness of the blends. PC with MFR = 3 is essential to produce the toughest PC/PET/rubber blend. The presence of rubber slightly relieves the strain rate sensitivity on yield stress increase. Lower MFR PC in the blend results in smaller activation volume and, therefore, higher strain rate sensitivity, because a greater number of chain segments are involved in the cooperative movement during yielding. Two separate modes, localized and mass shear yielding, work simultaneously in the rubber toughening mechanism. The plane‐strain localized shear yielding dominates the toughening mechanism at lower temperatures and brittle failure, while the plane‐stress mass shear yielding dominates at higher temperatures and ductile failure. The critical precrack plastic zone volume has been used to interpret the observed phenomenon. © 1994 John Wiley & Sons, Inc.
Thermoplastic interpenetrating polymer networks based on a poly(styrene‐b‐butadiene) copolymer and an ionically‐terminated polybutadiene ionomer
Authors: Ali S. A. M. , Hourston D. J. 
Published: April 2003

AbstractThermoplastic interpenetrating polymer networks (IPN) are mixtures of two physically crosslinked polymers. Thermoplastic IPNs were prepared by blending an SBS triblock elastomer with a 1,2‐polybutadiene that was ionically‐terminated at both ends. The morphologies of these IPNs were studied using differential scanning calorimetry and dynamic mechanical thermal analysis. It was concluded that the ionomer was incompatible with the SBS elastomer, since the Tgs of both the 1,2‐polybutadiene from the ionomer and the essentially 1,4‐polybutadiene from the SBS component were observable at temperatures that were close to those of the individual components. The addition of the polybutadiene material had, however, an influence on the relaxation processes of the polystyrene blocks. The polystyrene glass transition in the pure SBS copolymer is broadened by the interfacial region between polystyrene and polybutadiene. The low temperature shoulder was much more pronounced when the ion‐terminated polybutadiene was present, indicating it has a preference to be located in these interfacial regions. © 1994 John Wiley & Sons, Inc.
Studies on selective adsorption resins. XXXIII. Behavior of macroreticular chelating resins containing phosphinic and/or phosphonic acid groups in the adsorption of trivalent lanthanides
Authors: Egawa Hiroaki , Yamabe Kazunori , Jyo Akinori 
Published: April 2003

AbstractThe effect of the crosslinking and the porosity of the chelating resins containing phosphinic and/or phosphonic acid groups (RSP and RCSP) on uptake of trivalent lanthanides was studied; RSP and RCSP were prepared by hydrolysis of condensation products of phosphorus trichloride with styrene–divinylbenzene copolymer beads (RS) and with chloromethylated RS, respectively. From a series of RSs synthesized by systematically changing the amount of the crosslinker (divinylbenzene) or the porogen (2,2,4‐trimethylpentane), RSPs and RCSPs with different degrees of crosslinking and with different porosities were derived. Measurements of their uptake of La(III), Gd(III), or Yb(III) have clarified that RSP and RCSP with moderately crosslinked highly porous structures exhibit high capacities toward the lanthanides. Using these optimized RSP and RCSP and their respective oxidized derivatives RSPO and RCSPO, the distribution of all lanthanides (III) except for Pm(III) from aqueous hydrochloric acid solutions (0.1–1M) was examined. The distribution of each lanthanide(III) at a given concentration of the acid increases in the order RCSPO ≈ RCSP < RSPO < RSP. Their lanthanide selectivity patterns resemble one another; the selectivity increases with increasing the atomic number of the lanthanides except for the elements from Sm to Ho. In order to illustrate usefulness of these resins in the separation of lanthanides, the chromatographic separation of La(III), Nd(III), and Sm(III) was conducted using columns packed with RCSP. The three lanthanides were successfully separated by the elution with 0.5M hydrochloric acid solution without use of any organic complexing reagents, such as EDTA. © 1994 John Wiley & Sons, Inc.
On the analysis of positron annihilation lifetime spectroscopy data in semicrystalline miscible polymer blend systems
Authors: Simon G. P. , Zipper M. D. , Hill A. J. 
Published: April 2003

AbstractA free volume probing technique, positron annihilation lifetime spectroscopy (PALS) is used to characterize miscible blends of amorphous polycarbonate with a semicrystalline copolyester at room temperature. The paper describes the analysis required to use the PALS technique to probe the amorphous regions in which the miscibility of the blends occurs. Analysis of the raw PALS data in this system involves taking account of the influence of crystallinity on the PALS results. The results demonstrate that the PALS technique is able to discriminate between free volume in the amorphous regions of as‐molded and annealed samples. This difference in free volume between samples of differing thermal history is assigned to the influence of polymer crystals on the stress state of the miscible amorphous regions. © 1994 John Wiley & Sons, Inc.
Characterization of electropolymerized graphite fiber–polyacrylamide composites
Authors: Iroh J. O. , Suhng Y. , Labes M. M. 
Published: April 2003

AbstractThe synthesis of a series of graphite fiber‐polyacrylamide composites was performed electrochemically in dilute sulfuric acid (0.125M)‐acrylamide (2M) solution, 1 : 1 sulfuric acid (0.25M) : acetone‐acrylamide (2M) solution, and 1 : 1 sulfuric acid (0.25M) : 2‐propanol‐acrylamide (2M) solution, respectively, using graphite fiber bundles as the working electrode. The graphite fiber‐polyacrylamide composites, synthesized in a 1 : 1 2‐propanol : sulfuric acid‐acrylamide solution, were more easily characterized than those synthesized from the sulfuric acid‐acrylamide solution that contained no alcohol. Composites that were synthesized in a dilute sulfuric acid solution were, however, more readily crosslinked. (Fourier transform infrared spectroscopy, FTIR, confirmed the formation of inter‐chain and intrachain imide functional groups after the resin was cured at ≈ 200°C.) Polymer weight gain analysis, coupled with surface morphology studies using scanning electron microscopy, showed that the thickness of the coatings, and hence the volume fraction of the resin in the composites, varied linearly with the time of electropolymerization. Scanning electron microscopy revealed an open and folded chain surface structure, which permitted unrestricted permeation of the monomer onto the electrode surface. Differential scanning calorimetry of the electropolymerized resins confirmed a glass transition temperature of between 180 and 207°C. © 1994 John Wiley & Sons, Inc.
Synthesis of bifunctional ion‐exchange resins through the Arbusov reaction: Effect on selectivity and kinetics
Authors: Trochimczuk Andrzej W. , Alexandratos Spiro D. 
Published: April 2003

AbstractBifunctional ion‐exchange resins are synthesized from vinylbenzyl chloride—styrne copolymers. The two types of functional groups are introduced by an Arbusov reaction followed by sulfonation. The effect of ligand ratios, macroporosity, and matrix rigidity on the complexation of Eu (III) from solutions of low pH is quantified. It is found that ion complexation kinetics and selectivity are maximized with resins having both sulfonic and phosphonic acid ligands. Maximum metal ion complexation rates depend on a balance between chemical interactions (i.e., a bifunctional network interacting with a given substrate through an access and a recognition mechanism) and physical parameters (i.e., matrix porosity and rigidity). Structural integrity must be maintained through an appropriate crosslink level in order for the advantage of bifunctionality to be maintained in low‐pH solutions. © 1994 John Wiley & Sons, Inc.
Effect of copper oxides on the thermal oxidative degradation of the epoxy resin
Authors: Hong S. G. , Wang T. C. 
Published: April 2003

AbstractThe effect of copper oxides on the thermal oxidative degradation of a brominated epoxy resin–dicyandiamide system was studied using Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The addition of small amounts of Cu2O or CuO fillers to the epoxy resins affected the relative amounts of highly reacted cyclic species formed during thermal aging and induced catalytic degradation of the epoxy resins. The overall and initial activation energies of the degradation process were found to decrease, and the order in the degradation kinetics of the epoxy resin changed from a near zero order to negative domain (autocatalytic nature) in the presence of copper oxides. © 1994 John Wiley & Sons, Inc.
Synthesis and characterization of hydroxamic acid resin of poly(4‐vinyl‐2′‐carboxybenzophenone)
Authors: Kamble K. J. , Patkar D. N. 
Published: April 2003

AbstractThe synthesis and characterization of poly(hydroxamic acid) ion‐exchange resin from a poly(carboxylic acid) resin is described and its exchange properties for Cu(II), Ni(II), and Fe(III) are studied. The metal polychelates are investigated by magnetic measurements, diffuse reflectance spectroscopy, and infrared spectroscopy. © 1994 John Wiley & Sons, Inc.
Flexibility improvement of epoxy resin by using polysiloxanes and their derivatives
Authors: Tong Jiangdong , Bai Ruke , Zou Yingfang , Pan Caiyuan , Ichimura Shigeki 
Published: April 2003

AbstractA study of increasing the flexibility and lowering the internal stress of the cured epoxy resing was carried out by using polysiloxanes capped with functional groups and premaking polysiloxane particles with d = 1.1 μm and narrow distribution. Polysiloxanes capped with functional groups were prepared by the reaction of X‐22‐163B with bisphenol‐A, hexanedioic acid, and decanedioic acid. Poly(dimethylsiloxane‐b‐arylester) was synthesized by the reaction of poly(dimethylsiloxane) (X‐22‐162C) with arylester oligomers. Polysiloxane particles were obtained by cycling the mixture of polysiloxanes containing a vinyl group and aSi–H group, respectively, emulsifier, and water in homogenizer. When oily polysiloxanes were used to improve the flexibility of epoxy resin, good compatibility of polysiloxanes with epoxy resion, and high molecular weight capped with epoxy group favor the formation of small‐sized particles and homogeneous dispersion in the cured matrix. Comparisons were made among the epoxy resing modified with oily polysiloxanes capped with different functional groups. The results indicate that lightly crosslinked polysiloxane particles with d = 1.1 μm and narrow distribution have the greatest increase of elongation and biggest decrease of internal stress. The reason for this is discussed. © 1994 John Wiley & Sons, Inc.
Measurements of ultrasonic velocity and attenuation in biaxially oriented polypropylene films using fast fourier transform
Authors: Malinarič Svetozár 
Published: April 2003

AbstractThe first part of this study deals with the design of a new instrument for measuring the velocity and attenuation of ultrasonic waves propagating in thin polymeric films. The experimental results indicate a large anisotropy. In addition, a strong velocity and attenuation dependence on both frequency and temperature has been observed. The results are explained by means of phenomenological theory. © 1994 John Wiley & Sons, Inc.
Silicon contamination of substrates in fluorocarbon plasmas produced in glass reactors
Authors: Denes Ferencz , Sarmadi Majid , Hop C. E. C. A. , Buncick Milan , Young Raymond 
Published: April 2003

AbstractExtensive research has been carried out in recent years using fluorocarbon plasmas for modification and depositions on polymer substrates. In some cases anomalous results have been obtained that are not explainable based on conventional fluorine chemistry. In this investigation pure polypropylene films were exposed to carbon tetrafluoride plasmas in a Pyrex glass reactor. At short reaction times (less than 1 min) significant amount of silicon was detected by ESCA on the surface of the films. Analysis of liquid nitrogen trapped fluorocarbon plasma gases and molecular fragments indicated high concentrations of silicon and carbon containing species, the former indicative of ablation and etching reactions of the glass reactor walls. The production of a relatively high quantity of fluorosilicon derivatives was explained by the greater affinity of silicon for fluorine than for carbon, with the tendency to readily form SiF4. These fluorosilicon radical and ionic species generated under cold plasma conditions can easily react with polymeric substrates causing unexpected surface modifications. In addition Si–F bonds could be readily hydrolyzed to SiOH islands on the surface of the substrate to impart anomalous characteristics. © 1994 John Wiley & Sons, Inc.
Degradation of respirable fibrils of poly(p‐phenylene terephthalamide) by solar ultraviolet radiation
Authors: Knoff Warren F. 
Published: April 2003

AbstractAfter ∼ 160 days in the environment, the polymer in a respirable‐size poly(p‐phenylene terephthalamide) fibril (diameter = 0.3 μm) is expected to degrade, due to solar ultraviolet radiation, from an initial molecular weight of ∼ 20,000 to less than 400. This estimate is based on ultraviolet absorption characteristics, photolytic degradation kinetics, and judgments regarding how these translate into actual time in the environment. Degradation to this molecular weight level will cause the fibril tensile strength and modulus to decrease to ∼ 1% of their initial values. Mechanically, such a degraded fibril will be weak and brittle with properties similar to those of uncooked spaghetti. © 1994 John Wiley & Sons, Inc.
Studies on the synthesis and properties of copolyesterimide
Authors: Li Chien‐Hui , Chen Chih‐Chiang , Chen Ker‐Ming 
Published: April 2003

AbstractA series of copolyesterimides was prepared from bisphenol A, diacid (terephthalic acid [TPA] or isophthalic acid [IPA]), and 4‐carboxy‐N‐(p or m‐hydroxyphenyl) phthalimide (M1 or M2) in the presence of diphenyl chlorophosphate (DPCP) and pyridine as the direct condensation agent. Copolyesterimides derived from M1 showed poorer solubility than that of M2 during polymerization; a lower M1 content should be employed to prevent precipitation of the resulting polymers. The inherent viscosities of copolyesterimides were in the range of 0.33–0.56 dL/g. Some of these copolyesterimides were completely soluble in N‐methyl‐2‐pyrrolidone (NMP), N, N‐dimethylacetamide (DMAC), dimethylformamide (DMF), and m‐cresol. The thermal properties of copolyesterimides were examined by DSC and TGA. These copolyesterimides had glass transition temperatures in the range of 173–220°C and a 5% weight loss was observed in the range of 435–482°C. © 1994 John Wiley & Sons, Inc.
Polymeric thermoresistant blends based on poly‐SAN and imidized PMMA: Thermal and electrical characterization
Authors: Paciello G. , Saccani A. , Sandrolini F. , Frezzotti D. , Callaioli A. , Ravanetti G. P. 
Published: April 2003

AbstractBlends of styrene/acrylonitrile copolymers (poly‐SAN) with imidized PMMA exhibit increased thermoresistance in comparison with poly‐SAN alone. The miscibility of two modified poly(methyl methacrylate) (PMMA) with poly‐SAN has been evaluated with the aid of different techniques: isothermal calorimetry, through which mixing enthalpy and the Flory–Huggins χ parameter can be determined; dielectrical spectroscopy and thermally stimulated discharging currents (TSDC). The results obtained exhibit great consistency, thus supporting the usefulness of the applied methods for determining the mixing behavior of these polymer blends, which can be considered as model systems for thermoresistant ABS nowadays widely used in the automotive industry. Furthermore, the applied methods allow one to obtain useful data for the electrical application of the investigated blends. © 1994 John Wiley & Sons, Inc.
Precrack hysteresis energy in determining its ductile–brittle transition. III. Effect of temperature
Authors: Chang Feng‐Chih , Hsu Hon‐Chun 
Published: April 2003

AbstractA temperature variable has been used to correlate the precrack hysteresis energy and the corresponding ductility in terms of ductile–brittle transition behavior for polycarbonate. When the precrack plastic zone exceeds a critical value, crack extension thereafter will be effectively contained within the domain of the plastic zone and result in ductile fracture. Whether a specimen will fail in a ductile mode or a brittle mode is actually already being decided before the onset of crack initiation. The precrack elastic storage energy, total input energy minus hysteresis energy, is the major driving force to strain the crack tip for crack initiation. A higher testing temperature with lower yield stress converts a greater fraction of the input energy into the precrack hysteresis energy and relieves the storage strain energy available for crack initiation. A polycarbonate‐toughening mechanism of incrasing temperature is very similar to the presence of rubber by reducing yield stress and increasing the precrack plasticity. © 1994 John Wiley & Sons, Inc.