bluuebunny/crossref_metadata_2025_split huggingface dataset:
Blends composed of poly(N‐isopropylacrylamide) and an ethylene/vinyl alcohol copolymer: Thermal and morphological studies
Authors: Mano Valdir , Ribeiro e Silva Maria Elisa Scarpelli , Barbani Niccoletta , Giusti Paolo 
Published: November 2003

AbstractBlends of poly(N‐isopropylacrylamide) (PNIPAM) and an ethylene/vinyl alcohol copolymer (EVAL) were obtained through casting from dimethyl sulfoxide (DMSO) solutions and phase inversion in 50/50 DMSO/H2O solutions. The miscibility and morphology of the PNIPAM/EVAL blends were investigated with thermal and morphological analysis. Differential scanning calorimetry indicated that the crystallinity of EVAL decreased with increasing PNIPAM content and that the blends cast from DMSO/H2O solutions were miscible in the melt state. Measurements of the melting point depression allowed the determination of the interaction energy density (B) and Flory–Huggins interaction parameter (χ12) with the Nishi–Wang equation. The negative B and χ12 values obtained were examined in terms of the specific intermolecular interactions between the polymers. Scanning electron micrographs revealed that blends obtained by the casting method led to dense membranes, whereas the phase‐inversion method rendered typical macroporous membranes. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 501–505, 2004
Effect of a chain extender on the crystallization behavior of nylon 66
Authors: Ding Xuejia , Rong Jianhua , Xu Riwei , Yu Dingsheng , Yang Zhenzhong 
Published: November 2003

AbstractThe crystallization behaviors and crystalline morphologies of initial and chain‐extended nylon 66 samples were studied with differential scanning calorimetry and polarizing microscopy, respectively. The crystallization rate increased and the size of the spherulites decreased with chain‐extension. In addition, a two‐peak behavior was observed in chain‐extended nylon 66. These results showed that for the chain‐extended nylon 66, there was heterogeneous nucleation during crystallization. Therefore, the chain extender possibly functioned as a nucleating agent at the same time. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 68–71, 2004
Facile synthesis of novel optically active poly(amide‐imide)s containing N,N′‐(pyromellitoyl)‐bis‐l‐phenylalanine diacid chloride and 5,5‐disubstituted hydantoin derivatives under microwave irradiation
Authors: Faghihi Khalil , Zamani Khosrow , Mirsamie Azzizullah , Mallakpour Shadpour 
Published: November 2003

AbstractPyromellitic dianhydride (1,2,4,5‐benzenetetracarboxylic acid 1,2,4,5‐dianhydide) (1) was reacted with L‐phenylalanine (2) in a mixture of acetic acid and pyridine (3 : 2) at room temperature, then was refluxed at 90–100°C and N,N′‐(Pyromellitoyl)‐bis‐L‐phenylalanine diacid (3) was obtained in quantitative yield. The imide‐acid (3) was converted to N,N′‐(Pyromellitoyl)‐bis‐L‐phenylalanine diacid chloride (4) by reaction with thionyl chloride. Rapid and highly efficient synthesis of poly(amide‐imide)s (6a–f) was achieved under microwave irradiation by using a domestic microwave oven from the polycondensation reactions of N,N′‐(Pyromellitoyl)‐bis‐L‐phenylalanine diacid chloride (4) with six different derivatives of 5,5‐disubstituted hydantoin compounds (5a–f) in the presence of a small amount of a polar organic medium that acts as a primary microwave absorber. Suitable organic media was o‐cresol. The polycondensation proceeded rapidly, compared with the conventional melt polycondensation and solution polycondensation, and was almost completed within 10 min, giving a series of poly(amide‐imide)s with inherent viscosities about 0.28–0.44 dL/g. The resulting poly(amide‐imide)s were obtained in high yield and are optically active and thermally stable. All of the above compounds were fully characterized by means of FTIR spectroscopy, elemental analyses, inherent viscosity (ηinh), solubility test and specific rotation. Thermal properties of the poly(amide‐imide)s were investigated using thermal gravimetric analysis (TGA). © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 516–524, 2004
Crude and modified corncobs as complexing agents for water decontamination
Authors: Clave E. , François J. , Billon L. , Sèbe G. , Jéso B. De , Guimon M. F. 
Published: November 2003

AbstractThe ability of corncobs to retain copper ions was studied with respect to the origin of the materials (inner or outer parts of the cobs), the granulometry, the pH, and chemical modifications with maleic anhydride (MA) and succinic anhydride (SA). Esterification, characterized by Fourier transform infrared and X‐ray photoelectron spectroscopy, led to a large increase in copper retention in comparison with unmodified corncobs. The retention capacity was improved up to 6 times with SA‐modified corncobs at pH 5. The adsorption behavior of MA‐ and SA‐grafted samples, with respect to copper, appeared to be different at pH 4 and pH 5, and this was attributed to a difference in the pKa values of the grafted carboxylic functions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 820–826, 2004
Study of compartmentalization in the polymerization of miniemulsions of styrene and butyl methacrylate
Authors: Ouzineb K. , Graillat C. , McKenna T. F. 
Published: November 2003

AbstractDifferent surfactant and costabilization systems were studied for the miniemulsion polymerizations of styrene (St) and of butyl methacrylate (BMA). It was found that the combination of sodium dodecyl sulfate, Triton X‐405, and octadecyl acrylate yielded excellent results. With this system all of the droplets initially present in the reactor polymerized. This stabilization system was then used in the study of compartmentalization of the monomer droplets in miniemulsion polymerization. Blends of BMA and St miniemulsions were prepared separately and polymerized together to study mass transfer in this system. It was observed that no matter is exchanged between the different phases. This compartmentalization was also demonstrated and exploited by producing a bimodal molecular weight distributions latex, achieved with a semicontinuous process. The lower MWD was created by adding a second miniemulsion containing a transfer agent. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 115–124, 2004
Phase structural analyses of polyethylene coatings on high‐density papers. III. Determination of the crystallite thicknesses by T1 measurements
Authors: Furuheim Knut Magne , Axelson David E. , Antonsen Henrik W. , Helle Torbjørn 
Published: November 2003

AbstractTwo different extrusion‐coating qualities of polyethylene, namely LDPE and HDPE, were coated on high‐density papers. Differences were observed with respect to their response to storage and low temperature heat treatment. HDPE does not respond to storage at ambient temperature and heat treatment in the same way as LDPE. The LDPE‐coating exhibits an increase in the monoclinic crystalline fraction at the paper surface as a result of heat treatment. The nature of this response appears to be a result of adhesion to a paper surface, the properties of this surface, orientation of polymer chains, and chain mobility differences. The increase of the monoclinic fraction is shown to relate to an increase of the mean crystallite thickness and initiation of new crystallites at the paper surface. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 235–241, 2004
RF sputter deposition of poly(tetrafluoroethylene) films as masking materials for silicon micromachining
Authors: Bodas Dhananjay S. , Patil Sheetal J. , Mandale A. B. , Gangal S. A. 
Published: November 2003

AbstractPolymers have been studied extensively because of their wonderful array of properties. Their properties can be tailored by many means and can be made useful in many ways. Polymers can be crosslinked or branched and can provide different properties, such as conduction and passivation. This study dealt with the RF sputter deposition of poly(tetrafluoroethylene) (PTFE) films with the aim of using them as masking materials during the fabrication of various micromachined structures. The films were deposited on silicon substrates at different plasma powers (100, 150, and 200 W) for a constant deposition time (60 min). To test the masking properties, the deposited films were immersed in a 20 wt % aqueous KOH solution at 80°C for 60 min. The films showed lower contact angles and interfacial tension, and this indicated good adhesion of the films to the silicon substrates. Good adhesion is an essential quality of masking materials during micromachining. The structural properties of the as‐deposited and etched films were studied with Fourier transform infrared and X‐ray photoelectron spectroscopy. These indicated that the bonding groups and binding energies of CF and CCF matched the reported values well. Furthermore, the presence of CF and CCF bonds, even after the etching of silicon substrates in highly alkaline KOH solutions for 60 min, showed that the PTFE films remained unchanged in the etchant and, therefore, could function as good masking materials during the fabrication of micromachined structures. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1183–1192, 2004
In situfiber‐reinforced composites from blends containing polypropylene and polycaprolactone
Authors: Semba Takeshi , Kitagawa Kazuo , Endo Satoshi , Maeda Kazunori , Hamada Hiroyuki 
Published: November 2003

AbstractOur study was focused on the presupposition that morphology control in immiscible polymer blend could give rise to reinforcement in composites. To investigate the effects of shear and elongational flow in polymer processing, observation of the mechanical properties and the morphology of the polypropylene/polycaprolactone (PP/PCL) blend system was performed. PP/PCL sheets were fabricated by means of a single‐screw extruder equipped with a slit‐type die to which high shear and elongational stresses were applied. For the sake of comparison, a second series of composites of identical composition was compression molded with a hot‐press machine that transmits lower shear and elongational stresses. The results indicate that the extruded sheets have better mechanical properties than those of the compression‐molded sheets, a result attributed to the generation ofin situdispersed long fiber minor phases and cocontinuous phases in the extruded composites. The differences in the crystallization behavior of the fibrous and spherically shaped components were indicated clearly by DSC curves. A PP crystalline peak indicative ofin situPP fiber formation is conspicuous around 980 cm−1(PP crystalline band) in the FTIR spectrum. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 833–840, 2004
Hydrogen bonding effect on the poly(ethylene oxide), phenolic resin, and lithium perchlorate–based solid‐state electrolyte
Authors: Chen Hsien‐Wei , Jiang Chang‐Hung , Wu Hew‐Der , Chang Feng‐Chih 
Published: November 2003

AbstractThe interaction behavior of solid‐state polymer electrolytes composed of poly(ethylene oxide) (PEO)/novolac‐type phenolic resin and lithium perchlorate (LiClO4) was investigated in detail by DSC, FTIR, ac impedance, DEA, solid‐state NMR, and TGA. The hydrogen bonding between the hydroxyl group of phenolic and ether oxygen of the PEO results in higher basicity of the PEO. The higher basicity of the ether group can dissolve the lithium salts more easily and results in a greater fraction of “free” anions and thus higher ionic conductivity. DEA results demonstrated that addition of the phenolic increases the dielectric constant because of the partially negative charge on the ether group induced by the hydrogen bonding interaction between ether oxygen and the hydroxyl group. The study showed that the blend of PEO(100)/LiClO4(25)/phenolic(15) possesses the highest ionic conductivity (1.5 × 10−5 S cm−1) with dimensional stability. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1207–1216, 2004
PEEKWC ultrafiltration hollow‐fiber membranes: Preparation, morphology, and transport properties
Authors: Tasselli F. , Jansen J. C. , Drioli E. 
Published: November 2003

AbstractA series of hollow‐fiber membranes was produced by the dry–wet spinning method from PEEKWC, a modified poly(ether ether ketone) with good mechanical, thermal, and chemical resistance. The fibers were prepared under different spinning conditions, varying the following spinning parameters: polymer concentration in the spinning solution, height of the air gap, and bore fluid composition. The effect of these parameters on the water permeability, the rejection of macromolecules (using dextrane with an average molecular weight of 68,800 g/mol), and the morphology of the membranes was studied. The results were also correlated to the viscosity of the spinning solution and to the ternary polymer/solvent/nonsolvent phase diagram. The morphology of the cross section and internal and external surfaces of the hollow fibers were analyzed using scanning electron microscopy (SEM). All membranes were shown to have a fingerlike void structure and a skin layer, depending on the spinning conditions, varying from (apparently) dense to porous. Pore size measurements by the bubble‐point method showed maximum pore sizes ranging from 0.3 to 2 μm. Permeability varied from 300 to 1000 L/(h−1 m−2 bar) and rejection to the dextrane from 10 to 78%. The viscosity of polymer solutions was in the range of 0.2 to 3.5 Pa s. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 841–853, 2004
One‐step synthesis and ring‐opening polymerization of novel macrocyclic(arylene multisulfide) oligomers
Authors: Chen K. , Meng Y. Z. , Tjong S. C. , Hay A. S. 
Published: November 2003

AbstractA series of macrocyclic(arylene multisulfide) oligomers were synthesized under high dilution conditions by reacting diphenyl ether/diphenyl/diphenyl disulfide/diphenyl methane with dichloro disulfide in the presence of a trace amount of iron powder by a one‐step reaction. From MALDI‐TOF mass spectra, it was established that the repeating units of the cyclization ranged from two to seven and the unit of macrocyclic(arylene multisulfide) oligomers had one to seven sulfur atoms. The macrocyclic oligomers readily underwent ring‐opening polymerization in the melt, resulting in linear, high molecular weight polymultisulfides. DSC thermograms demonstrated that the four polymultisulfides, derived from the macrocyclic(arylene multisulfide) oligomers, are amorphous in nature. The macrocyclic(arylene multisulfide) oligomers and polymers were analyzed by MALDI‐TOF‐MS, IR, HPLC, NMR, DSC, and TGA methods. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 735–741, 2004
Packaging‐related properties of alkyd‐coated, wax‐coated, and buffered chitosan and whey protein films
Authors: Gällstedt M. , Hedenqvist M. S. 
Published: November 2003

AbstractPackaging‐related properties of coated films of chitosan–acetic acid salt and whey protein concentrate (WPC) were studied. Chitosan (84.7% degree of deacetylation) and WPC (65–67% protein) were solution cast to films. These films are potential oxygen barriers for use in packaging. Coatings of wax or alkyds were used to enhance the water‐barrier properties. The packaging‐related properties of chitosan films treated in a buffering solution, with a pH of 7.8, were also investigated. The coated films were characterized with respect to Cobb absorbency, overall migration to water, water vapor transmission rate, and oxygen permeability. The creasability and bending toughness were determined. The wax was a more efficient barrier to liquid water and 90–95% relative humidity than the alkyd. However, the alkyd‐coated material had superior packaging‐converting properties. The alkyd‐coated WPC and chitosan–salt films were readily folded through 180° without any visible cracks or delamination. The overall migration from the alkyd‐coated materials was below the safety limit, provided the coat weight was higher than 7.5 mg/cm2 on WPC and 2.1 mg/cm2 on chitosan–salt. The barrier properties of chitosan film under moist conditions were improved by the buffer treatment. However, the buffering also resulted in shrinkage of the film. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 60–67, 2004
Influence of thermal treatments, molecular weight, and molecular weight distribution on the crystallization of β‐isotactic polypropylene
Authors: Marigo Antonio , Marega Carla , Causin Valerio , Ferrari Paolo 
Published: November 2003

AbstractSix samples of isotactic polypropylene were examined to study the influence of the thermal treatments and the molecular weights and their distribution on the β‐crystallization of the polymer. The highest amount of the β‐phase was obtained by isothermal crystallization and in correspondence of high average molecular weights and wide molecular weight distributions. Small‐angle X‐ray scattering pointed out that a partial β‐crystallization seems not to influence the lamellar morphology parameters. Differential scanning calorimetry measurements, at different heating rates, allowed us to confirm that the multiple melting endotherms behavior of the β‐phase is to be correlated to a melting–recrystallization–melting mechanism. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1008–1012, 2004
Effects of calcium ion on polyester‐type polyurethane emulsion and properties of polyurethane film
Authors: Lou Zhaowen , Luo Jun , Zhan Hongju 
Published: November 2003

AbstractPolyurethane (PU) emulsions were prepared from polytetramethylene adipate diol, toluene diisocyanate, dimethanol propionic acid, and so forth. The effects of calcium ion on the stability of PU emulsion as well as on the water‐resistance property, tensile strength, and tensile yield of PU film were discussed. The results show that calcium ion can quickly damage the stability of PU emulsion. Meanwhile, calcium ion can distinctly counteract the unfavorable effects water has on the tensile properties of PU film. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1285–1288, 2004
Effect of organo‐phosphorus and nano‐clay materials on the thermal and fire performance of epoxy resins
Authors: Hussain M. , Varley R. J. , Mathys Z. , Cheng Y. B. , Simon G. P. 
Published: November 2003

AbstractThe results of flame retardance and thermal stability of a reactively modified organo‐phosphorus diglycidylether of bisphenol‐A and an organo‐phosphorus tetraglycidyl diaminodiphenylmethane are reported here. The organo‐phosphorus epoxy resins were synthesized by the reaction of 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide and diglycidyl ether of bisphenol‐A and tetraglycidyl diaminodiphenylmethane, respectively, and then cured with a mixture of 3,5‐diethyltoluene‐2,4‐diamine and 3,5‐diethyltoluene‐2,6‐diamine. In addition to this, between 5 and 7.5% of organically modified polymeric layered silicate nano‐clay was also added to neat epoxy resin or to the phosphorus‐modified epoxy resin to investigate any synergies, or otherwise, a combination of clay and phosphorus on the flame, degradation, and thermal properties are also reported. The reaction kinetics of phosphorus‐modified and epoxy cure were studied by FTIR, 1H‐NMR, and DSC. Thermal properties and morphology of the final product were analyzed by thermogravimetric analysis, dynamic mechanical thermal analysis, X‐ray diffraction, and cone calorimetry. Improvement in flame retardance by cone calorimetry was demonstrated by the addition of only 3% phosphorus or 7.5% clay into the epoxy compared with unmodified epoxy resins, whereas no evidence of synergy for a phosphorus and clay combination was found. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1233–1253, 2004
Application of chitosan‐entrapped β‐galactosidase in a packed‐bed reactor system
Authors: Wentworth Danielle S. , Skonberg Denise , Donahue Darrell W. , Ghanem Amyl 
Published: November 2003

AbstractThe model enzyme β‐galactosidase was entrapped in chitosan gel beads and tested for hydrolytic activity and its potential for application in a packed‐bed reactor. The chitosan beads had an enzyme entrapment efficiency of 59% and retained 56% of the enzyme activity of the free enzyme. The Michaelis constant (Km) was 0.0086 and 0.011 μmol/mL for the free and immobilized enzymes, respectively. The maximum velocity of the reaction (Vmax) was 285.7 and 55.25 μmol mL−1min−1for the free and immobilized enzymes, respectively. In pH stability tests, the immobilized enzyme exhibited a greater range of pH stability and shifted to include a more acidic pH optimum, compared to that of the free enzyme. A 2.54 × 16.51‐cm tubular reactor was constructed to hold 300 mL of chitosan‐immobilized enzyme. A full‐factorial test design was implemented to test the effect of substrate flow (20 and 100 mL/min), concentration (0.0015 and 0.003M), and repeated use of the test bed on efficiency of the system. Parameters were analyzed using repeated‐measures analysis of variance. Flow (p< 0.05) and concentration (p< 0.05) significantly affected substrate conversion, as did the interaction progressing from Run 1 to Run 2 on a bed (p< 0.05). Reactor stability tests indicated that the packed‐bed reactor continued to convert substrate for more than 12 h with a minimal reduction in conversion efficiency. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1294–1299, 2004
Resistivity‐temperature behavior of carbon fiber filled semicrystalline composites
Authors: Di Weihua , Zhang Guo 
Published: November 2003

AbstractCarbon fiber (CF) filled low‐density polyethylene (LDPE) composites were prepared by the conventional melt‐mixing method. The distribution of CF in the composite was studied by wide‐angle X‐ray diffraction (WAXD) and scanning electron microscope (SEM) observations. A phenomenological model was proposed to illustrate the resistivity‐temperature behavior of CF‐filled semicrystalline composites. The effects of the content and aspect ratio of CF on the positive temperature coefficient (PTC) and the room temperature resistivity were elucidated. A balance between the PTC intensity and the room‐temperature resistivity can be achieved by using a mixture of CFs with low and high aspect ratios. The negative temperature coefficient (NTC) phenomenon can be effectively eliminated by crosslinking under γ‐ray radiation, and the crosslinked composite exhibits a higher PTC intensity and PTC transition temperature than the noncrosslinked counterpart. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1222–1228, 2004
Composition and long‐term stability of polyglycidol prepared by cationic ring‐opening polymerization
Authors: Timothy Royappa A. , Vogt Michael L. , Sharma Venkatanarayanan 
Published: November 2003

AbstractPolyglycidol synthesized by cationic ring‐opening polymerization of glycidol (boron trifluoride initiation in dichloromethane) was purified of low molecular weight contaminants by centrifugal filtration. The high and low molecular weight fractions were characterized by NMR, GPC, osmometry, viscometry, DSC, and FTIR. The 13C‐NMR spectrum of this polymer was completely annotated by proposing a new step in the reaction mechanism. The four thermal dimers of glycidol were also isolated and identified as 2,5‐bis(hydroxymethyl)‐1,4‐dioxane and 2,6‐bis(hydroxymethyl)‐1,4‐dioxane, each of which can exist in cis and trans configurations. Polyglycidol was found to be hygroscopic, picking up about 5% by weight of atmospheric moisture. It was also found that, over time (ca. 1–2 years), polyglycidol crosslinks into a rubbery, insoluble mass. It is therefore recommended that this polymer be stored dry and used within a few months of synthesis. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1344–1351, 2004