bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on mesomorphic behaviors of segmented azoxy polyester containing polyoxyethylene
Authors: Huang Jaine Ming , Kuo Jen Feng , Chen Chuh Yung 
Published: April 2003

AbstractA series of a segmented copolymer, poly(4,4′‐dioxy‐2,2′‐dimethyl‐azoxybenzene dodecanedioyl)‐co‐polyoxyethylene 400 (PMABD‐co‐POE) was prepared; the average chain lengths n, of the PMABD studied are 8.1 to 20.6. The thermotropic properties and the mesophase texture of the segmented copolymers were elucidated as functions of n using a differential scanning calorimeter and a polarized optical microscope with a hot stage. The results show that the incorporation of POE with PMABD decreases the intermolecular interaction force and changes the chain flexibility. The nematic droplets obtained near the isotropic temperature all exhibited a twisted bipolar configuration. Also, in the undercooling process, the nematic textures obtained before crystallizing varied with n. The copolymers containing n ≥ 17, like PMABD, develop a Schlieren texture, whereas those containing n < 17 develop a distorted‐stripe conformation. A possible mechanism for interpretation of the obtained results has been proposed. © 1995 John Wiley & Sons, Inc.
Study of crosslinking density in polydimethylsiloxane networks by DSC
Authors: Vera‐Graziano R. , Hernandez‐Sanchez F. , Cauich‐Rodriguez J. V. 
Published: April 2003

AbstractA calorimetric study for estimating crosslinking densities of polydimethylsiloxane (PDMS) networks is presented. It involves the experimental determination of the heat capacities of the polymer with (C) and without (C) crosslinking. The theoretical basis of the method is described as well as the procedure used for the determination of the Cps. The crosslinking densities of PDMS networks, determined by absorbency (swelling) measurments, using the Flory‐Rehner equation, and by the method described here, are compared. The PDMS, obtained by the anionic synthesis of octamethylcyclotetrasiloxane, was analyzed by gel permeation chromatography and infrared spectroscopy. Separate samples of the polymer were further crosslinked at different network densities. The Cps and the thermal stabilities were determined by DSC and TGA, respectively. The results indicate that the crosslinking density ratios of the polymer networks calculated by the relation ΔC/C are in reasonable agreement with those obtained from absorbency measurements. The crosslinking density can also be obtained from heat capacity measurments if the density of the network is known at the temperature that ΔCp is obtained. © 1995 John Wiley & Sons, Inc.
General formula for bending beam determination of case II diffusion in polymer‐containing bilayer structures
Authors: Jou Jwo‐Huei , Yang An‐Kuo , Chang Ying‐Lun , Jou Jwo‐Min 
Published: April 2003

AbstractAn exact formula has been presented to correlate the bending curvature cariation ratio, Ω, of any given bilayer structure comprising a solvent‐swellable polymer layer with diffusion time, t, under case II diffusion. The formula can be used to determine the diffusion front velocity, v, for layered structures comprising a thick polymer film on a thin substrate or vice versa when subjected to solvent diffusion. According to this formula, there is little effect from plasticization or swelling in the transverse direction on the diffusion curve of Ω vs. t if the polymer layer to be investigated is relatively thin and its intrinsic hygroscopic strain ratio is less than unity. By using this model, the diffusion of N‐methyl pyrollidinone (NMP) in a 18‐μm rodlike pyromellitic dianhydride p‐phenylene‐diamine (PMDA‐PDA) polymide film, coated on a 75‐μm silicon substrate, is found to be case II with a diffusion front velocity of 1.84 × 10‐7 cm/s. © 1995 John Wiley & Sons, Inc.
Structure and properties of tin‐containing polymers deposited from tetramethyltin HF plasma
Authors: Ying T. H. , Sarmadi A. M. , Hop C. E. C. A. , Denes F. 
Published: April 2003

AbstractThere has been an increasing interest in depositing metal or metal‐containing thin films through plasma polymerization for various applications. This work deals with the plasma graft polymerization of tetramethyltin (TMT) on polypropylene surfaces with an aim of producing special electrical and optical coatings. The fragmentation of TMT under cold plasma conditions and the recombination of discharge‐generated active species were studied by analyzing the resulting molecular mixture trapped outside of the plasma zone by HR‐MS and GC‐MS techniques. It was found that the predominant ionic fragment is m/z = 165, and the most probable intermediate structure of the polymer formation mechanism is hexamethylditin. The structure of polymeric layers deposited on various substrates were investigated by ESCA and FT‐IR methods. Intense oxidation of tin‐based polymeric layers were observed under open laboratory conditions. The existence of weak SnSn and SnC bonds in the polymeric structure is suggested to be responsible for this reaction. This phenomenon was associated with enhanced UV transparency. Based on analytical data a plasma‐enhanced polymerization mechanism of TMT is proposed. © 1995 John Wiley & Sons, Inc.
Application of poly(vinyl alcohol) with an alkyl end group containing anionic groups to coal–water slurry as a dispersant
Authors: Yamauchi Junnosuke , Terada Kazutoshi , Sato Toshiaki , Okaya Takuji 
Published: April 2003

AbstractAnionic groups were introduced with copolymerization of corresponding vinyl monomers with vinyl acetate into poly(vinyl alcohol) (PVA) with an alkylthio end group. The polymers were investigated as a dispersant for coal‐water slurry (CWM). Anionic groups such as sodium sulfonate and sodium carboxylate enhance remarkably the ability of PVA with an alkylthio end group to disperse coal. Sodium polyacrylic acid with an alkyl end group also showed a good ability of dispersing coal. The order of the ability of dispersing coal in these polymeric dispersants along with sodium napthalene sulfonate formaldehyde condensate (NSF) varied by the kind of coal used. In cases of the polymeric dispersants, the fluidity of coal in terms of dependence of viscosity on shear rate also varied, from dilatency to thixotropy, in accordance with coal used. Impurities in coal as well as surface properties of coal particles might play important roles in the properties of CWM. © 1995 John Wiley & Sons, Inc.
The properties of soldering mask hardened by means of UV using acrylate and methacrylate oligomers
Authors: Matynia Tadeusz , Kutyłkea Romualda , Bukat Krystyna , Pieńkowska Barbara 
Published: April 2003

AbstractThe properties of soldering masks based on epoxyacrylic, epoxymethacrylic esters, and monomers: 2‐ethylhexyl acrylate, triethylene glycol dimethacrylate, and triethylene glycol phthalate dimethacrylate have been described. The thixotropic properties, printability, adhesion to the surface, and resistance to soldering have been determined. © 1995 John Wiley & Sons, Inc.
Preferable structure of poly(ethylene glycol) for grafting onto a cellulosic membrane to increase hemocompatibility without reduction in solute permeability of the membrane
Authors: Kanamori Toshiyuki , Sakai Kiyotaka , Fukuda Makoto , Yamashita Yasuhiko 
Published: April 2003

AbstractSwelling layers formed by poly(ethylene glycol) (PEG) chains grafted onto surfaces of a cellulosic membrane are known to improve hemocompatibility of the membrane. Three types of hemodialysis membranes were derived from the same regenerated‐cellulose hollow‐fiber membrane by grafting PEG with different formulas onto the surfaces to clarify the influence of the grafted PEG chains on solute permeability of the membranes. Determination of volume fractions of nonfreezing water contained in the membranes by differential scanning calorimetry revealed that most of the PEG chains were grafted onto the external surfaces and less into the pores in the membranes. Permeability of vitamin B12 for the PEG‐grafted membranes except for the one with the shortest PEG chains was reduced as compared with the original membrane, while that of tritium‐labeled water for all the PEG‐grafted membranes was the same as that of the original membrane. Structural parameters only of the PEG‐grafted membrane with the largest alkyl groups at the terminal of the PEG chains were different from those of the other PEG‐grafted and original membranes. The shorter PEG chains with the larger terminal alkyl groups are suitable for grafting onto a cellulosic membrane to increase hemocompatibility of the membrane without significant reduction in the solute permeability of the membrane. © 1995 John Wiley & Sons, Inc.
Polymerization of phosphor‐containing oligomer induced by electron‐beam irradiation
Authors: Yoshizawa Iwao , Kohara Choji , Kaji Kanako , Hatada Motoyoshi 
Published: April 2003

AbstractStudies have been carried out on the polymerization of vinyl phosphonate oligomer in a form of thin liquid layer induced by electron‐beam irradiation under various reaction conditions. It was found that the dose‐rate exponent on the rate of polymerization was 0.92, that the presence of remaining diluent below 10% did not disturb the polymerization, but that the presence of oxygen retarded the reaction when the film thickness was as thin as 20μm. Intermittent irradiation was effective to increase the conversion to the polymer. © 1995 John Wiley & Sons, Inc.
Assessment of degree of fusion of rigid PVC from inverse gas chromatographic measurements
Authors: Qin Renyan , Schreiber H. P. , Rudin Alfred 
Published: April 2003

AbstractInverse gas chromatography of alkanes has been used to assess the degree of fusion of rigid polyvinyl chloride (PVC) extrudates. The relative degree of fusion is provided by ratios of the retention volumes of the alkane probe molecules in the bulk of the PVC. This method is nonintrusive and can be used to measure degree of fusion quantitatively if a completely fused reference material can be provided. The present analysis involves evaluations of the contributions to the overall retention volume of the alkane probes, resulting from adsorption and from bulk diffusion. The diffusivity of the alkanes was clearly dependent on the processing history of the PVC extrudate. A direct variation was observed between the size of the diffusing molecules and their residence time as adsorbates on the polymer surface. © 1995 John Wiley & Sons, Inc.
Introduction of amidoxime groups into cellulose and its ability to adsorb metal ions
Authors: Kubota Hitoshi , Shigehisa Yasumichi 
Published: April 2003

AbstractIntroduction of amidoxime groups into cellulose substrate was investigated by reaction of cyano‐group‐containing celluloses such as cyanoethylcellulose (CE‐Cell) and acrylonitrilegrafted cellulose (G‐Cell) with hydroxylamine at 70°C in water medium (pH = 7.0). Dissolving pulp from softwood was used as the cellulose sample, and photografting was applied to the preparation of G‐Cell, where hydrogen peroxide was used as a photoinitiator. Degree of substitution (DS) of CE‐Cell and percent grafting of G‐Cell employed were less than 1.5 and 40, respectively. The amidoximation of CE‐Cell proceeded easily, and the amidoxime content increased with increasing the reaction time and increasing the concentration of hydroxylamine, but the amidoxime content of G‐Cell decreased significantly at longer reaction time. The amidoximated samples prepared by CE‐Cell exhibited an ability to adsorb metal ions such as Cu2+, Ni2+, and Co2+, and the adsorbed amount of Cu2+ was highest among the three metal ions. Moreover, the adsorption of Cu2+ varied depending on the DS of CE‐Cell. That is, the absorption ability was reduced when the sample was prepared using CE‐Cell with higher DS. The amidoximated samples prepared from G‐Cell showed adsorption of Cu2+ similar to samples prepared by CE‐Cell with lower DS, irrespective of percent grafting. © 1995 John Wiley & Sons, Inc.
Instrumented impact testing of castor‐oil‐based polyurethanes
Authors: Liu T. M. , Bui V. T. 
Published: April 2003

AbstractInstrumented impact testing has been used to study castor‐oil‐based polyurethanes. The energy‐absorbed capacity of these materials in impact is dependent on several factors, such as the type of isocyanate, NCO/OH ratio, and testing temperature. An approximate but simple method for the low‐temperature impact testing was proposed. A change from ductile response to brittle fracture was observed as the temperature of the specimen was reduced. This characteristic ductile‐brittle transition temperature is to be found highly sensitive to crosslinking degree. © 1995 John Wiley & Sons, Inc.
Copolymers of methyl methacrylate and acrylate comonomers: Synthesis and characterization
Authors: Bhabhe M. D. , Galvankar P. S. , Desai V. M. , Athawale V. D. 
Published: April 2003

AbstractMethyl methacrylate (MMA) has been copolymerized with n‐butyl acrylate (n‐BA), ethyl acrylate (EA), and 2‐ethylhexyl acrylate (2‐EHA) in solution at 70°C using benzoyl peroxide as free radical initiator. The copolymer composition was estimated by the 1H‐NMR spectroscopic technique. The copolymers were further characterized by IR, XRD, TGA, DTA, DSC, GPC, and solubility. The adhesive characteristics of the copolymers to cellulosic substrate are also reported. © 1995 John Wiley & Sons, Inc.
Monitoring of lamination processes in an autoclave with fiber‐optic infrared spectroscopy
Authors: Ge Zhengfang , Brown Chris W. , Brown Michelle 
Published: April 2003

AbstractCuring reactions of certain laminates involve a series of chemical structure changes which occur with increasing temperature and/or pressure. This paper describes the use of a midinfrared chalcogenide fiber to monitor the lamination of polymer prepregs in an autoclave. The fiber optic was used both as a wave guide and as a sensing element for acquiring evanescent wave spectra. The spectra were measured by embedding the fiber optic in a polymer prepreg package. The polymer prepregs studied include epoxy, polyimide, and bismaleimide triazine (BT) resins. The degree of cure and an understanding of the kinetic processes were obtained from the absorbance changes in specific bands. This in situ sampling technique demonstrates a new area of Fourier transform infrared (FTIR) spectroscopy for following the formation of polymeric bonds. © 1995 John Wiley & Sons, Inc.
Preparation of high performance PET fiber by solution spinning technique
Authors: Wu Gang , Cuculo John A. 
Published: April 2003

AbstractHigh molecular weight poly(ethylene terephthalate) (PET, IV = 3.30 dL/g) was extruded in attempts to prepare high performance fiber using the solution spinning method. Solution preparation, fiber coagulation, and mechanical properties of resultant fibers were examined. An as‐spun fiber exhibited high deformability when appropriate coagulation conditions were used. Tenacity and modulus of the resultant drawn fibers achieved 12.9 and 230 gpd, respectively, at draw ratio above 10. © 1995 John Wiley & Sons, Inc.
Fabrication and characterization of planar and channel polymer wave guides. I. Plasma‐polymerized HMDS films
Authors: Zeik D. B. , Dugan J. R. , Schroeder D. W. , Baur J. W. , Clarson S. J. , De Brabander G. N. , Boyd J. T. 
Published: April 2003

AbstractPlasma‐polymerized hexamethyldisiloxane (HMDS) films have been prepared as both planar and channel wave guides. The optical attenuation results measured in both the planar and channel HMDS wave guides were found to be similar, thus demonstrating that the inherent solvent resistance and chemical inertness of the plasma polymerized films allows the use of common photoresist techniques, including application of the photoresist, photomasking, and subsequent etching. This may be contrasted with wave guides made from conventional polymers, where careful consideration must be given to photoresist/polymer compatibility, because the photoresist solvents may adversely affect the underlying polymer and lead to degradation of the material during processing. © 1995 John Wiley & Sons, Inc.
The charpy impact fracture behavior of phenolphthalein polyether ketone
Authors: Han Yanchun , Yang Yuming , Li Binyao , Wang Xuhui , Feng Zhiliu 
Published: April 2003

AbstractThe Charpy impact fracture behavior of notched specimens of phenolphthalein poly(ether ketone) (PEK‐C) has been studied over a range of temperature using a JJ‐20 Model instrumented impact tester. For PEK‐C, there exist two temperature regions which distinguish the fracture mechanism, and the brittle fracture was preferentially governed by slip or shear bands at relatively high temperatures, but by crazes at low temperatures. The temperature dependence of the ductility index (DI) shows similar peaks to the tan δ loss.
Fracture toughness of PC/PBT blend based on J‐integral methods
Authors: Lu Ming Luen , Chang Feng‐Chih 
Published: April 2003

AbstractThe fracture toughness of a polycarbonate/poly(butylene terephthalate) (PC/PBT) blend was determined using three different J‐integral methods, ASTM E813‐81, E813‐87, and hysteresis energy. The critical J values (J1c) obtained are largely independent of the cross‐head speed (range from 0.5 to 50 mm/min). ASTM E813‐81 and hysteresis energy methods result in comparable J1c values, while the E813‐87 method estimates J1c to be 60–80% higher. The critical displacement determined from the plots of hysteresis (energy and ratio) and the true crack growth length vs. displacement is very close. This indicates that the critical displacement determined by the hysteresis energy method is indeed the displacement at the onset of crack initiation and the corresponding J1c represents a physical event of crack initiation. © 1995 John Wiley & Sons, Inc.
Blends of poly(ethylene terephthalate) with co[poly(ethylene terephthalate‐p‐oxybenzoate)]. II. Composition effect on the rate of crystallization
Authors: Ou Cheng‐Fang , Lin Chen‐Chong 
Published: April 2003

AbstractPoly(ethylene terephthalate) (PET) was blended with four different kinds of co[poly(ethylene terephthalate‐p‐oxybenzoate)] copolyesters, designated P28, P46, P64, and P82, with the level of copolyester varing from 1 to 15 wt %. All samples were prepared by melt‐mixing in a Brabender Plasticorder for 8 min. The crystallization behavior of samples were then studied via DSC. The results indicate that these four copolyesters accelerate the crystallization rate of PET in a manner similar to that of a nucleating agent. The acceleration of the PET crystallization rate was most pronounced in the PET/P28 blends with a maximum level at 10 wt % of P28, and in the PET/P28 blends, at 5 wt % of P82. The melting endotherm onset temperatures and the melting peak widths for the blends are comparable with those of neat PET. These results imply that the stability of PET crystalline phase in the blends does not change by blending. The observed changes in crystallization behavior, however, are explained by the effect of the physical state of the copolyester during PET crystallization as well as the content of the p‐oxybenzoate (POB) moiety in corporated into the blends. © 1995 John Wiley & Sons, Inc.
Moisture‐activated, electrically conducting bioadhesive hydrogels as interfaces for bioelectrodes: Effect of formulation factors on cutaneous adherence in wet environments
Authors: Woolfson A. D. , McCafferty D. F. , McCallion C. R. , McAdams E. T. , Anderson J. Mcc. 
Published: April 2003

AbstractThe effect of varying the composition of a polymer blend containing poly(methylvinyl ether‐maleic anhydride) copolymer on the Brookfield viscosity of the blend and on the in vitro bioadhesive forces of resultant cast films was assessed. An increase in copolymer concentration increased both blend viscosity and film bioadhesion. Increasing the plasticizer concentration did not significantly alter bioadhesion but did influence film flexibility. Blend pH affected both viscosity and bioadhesion. However, for films to be biocompatible, formulation within the skin pH range was desirable. Films exhibited the ability to ‘restick’ after initial adherence, allowing repositioning of the adhered film in vivo. Factorial design experiments (22) showed that an additive bioadhesive effect occurred when copolymer and PVP concentrations were increased in the polymer blend. However, no interaction between copolymer and plasticizer was observed. Addition of sodium chloride to the polymer blend, necessary to render films electrically conducting for use as bioelectrode interfaces, decreased blend viscosity but did not exert a significant effect on film bioadhesion. © 1995 John Wiley & Sons, Inc.
A molecular weight model in vinyl chloride–divinyl monomer suspension copolymerization before the gel point
Authors: Yingwu Luo , Zuren Pan , Zhixue Weng , Zhiming Huang 
Published: April 2003

AbstractIn this paper, a molecular weight model in the vinyl chloride (VC)–divinyl monomer suspension copolymerization was derived from the mechanism of VC two‐phase polymerization, with pseudokinetic constant method and the theory of the moments of chain length distribution. Furthermore, the behavior of average polymerization degree was simulated with the model at varied experimental parameters. The simulation phenomena were discussed in detail. It is concluded that our model can be useful to predict the behavior of DPw and to look inside the crosslinking mechanism in the VC–divinyl monomer copolymerization. © 1995 John Wiley & Sons, Inc.
Iron(III) chelating resins. VI. Stability constants of iron(III)–ligand complexes on insoluble polymeric matrices
Authors: Feng Minhua , Does Leen Van Der , Bantjes Adriaan 
Published: April 2003

AbstractA method is presented for the determination of stability constants of iron(III)–ligand complexes on insoluble polymeric matrices based on a competition chelation reaction for iron(III) of the resin with a soluble chelator. Stability constants (K') were calculated for iron(III)–ligand complexes on DFO–Sepharose gel, HMP–Sepharose gel, AHMP–HEMA resin, and AHMP–DMAA resin. In these resins, desferrioxamine B (DFO, hexadentate ligand) or the 3‐hydroxy‐2methyl‐4(1H)‐pyridinone (HMP, bidentate ligand) was bound on insoluble polymeric matrices. The average values (log K') were: 26.6 (DFO–Sepharose); 37.9 (HMP–Sepharose); 27.2 (AHMP–HEMA); and 39.9 (AHMP–DMAA). The stability constants of the insoluble iron(III) complexes on the resins were compared with those of the corresponding soluble iron(III) complexes. The effect of immobilization on the constants was discussed, and it was found that a higher hydrophilicity and stability of a resin resulted in an increase of the stability constant, whereas steric hindrance decreased the stability constant. © 1995 John Wiley & Sons, Inc.
Cyclopolymerization of dodecanidiol dimethacrylate and identification of polymer structure
Authors: Huang Junlian , Hu Youqian , Ruyter I. Eystein 
Published: April 2003

AbstractDodecanidiol dimethacrylate (DDMA) was polymerized by a cyclization mechanism in low monomer concentration (0.075–0.5 mol/L) and high AIBN concentration (0.44−1.76 × 10−2). The linear soluble polymer was formed even if the conversion of DDMA was as high as 25.6%. The glass transition temperature of cyclized polyDDMA (PDDMA) is about 4.5°C, which is 65°C higher than its homolog—poly(dodecyl methacrylate). The structure of the polymer was established by infrared and 1H‐ and 13C‐NMR spectroscopy. The head‐to‐tail contents in cyclized PDDMA, i.e., the formation of a 20‐membered ring, is predominant compared with those of head‐to‐head contents of a 19‐membered ring. © 1995 John Wiley & Sons, Inc.
Determination of ZnO dispersion in rubber compounds
Authors: Jurkowski B. , Koczorowska E. , Goraczko W. , Manuszak J. 
Published: April 2003

AbstractIt was found that radioisotopic methods can be adapted for analysis of ZnO dispersion in rubber compounds. This method is characterized by a sensitivity of 10−6 g ZnO/1 g rubber compound. This fact enables application of this method in technological and research problems. © 1995 John Wiley & Sons, Inc.