bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of UV aging on the tensile and fracture mechanical response of syndiotactic polypropylenes of various crystallinity
Authors: Bárány T. , Földes E. , Czigány T. , Karger‐Kocsis J.
Published: January 2004

Syndiotactic polypropylene (sPP) sheets of various crystallinities were subjected to accelerated ultraviolet (UV) aging. The chemical modification of the polymer was followed by FTIR spectroscopy measuring the carbonyl index in transmittance (film) and diffuse reflectance (powder) modes. Both the tensile stress and strain, suitable indicators of the UV aging, changed linearly with the carbonyl index in semilogarithmic representation. The essential work of fracture (EWF) method proved to be less suitable for characterization, as the UV irradiation resulted in surface embrittlement of the polymer. This caused brittle fracture of the notched specimens instead of the required ductile one. On the other hand, the term of the specific work of fracture related to yielding may adequately reflect the structural and morphological changes of sPP caused by UV irradiation. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3462–3469, 2004
Photocationic and radical polymerizations by novel N‐phenacylammonium salts
Authors: Takahashi Eiji , Sanda Fumio , Endo Takeshi
Published: January 2004

Novel N‐phenacylammonium salts [N‐(α‐benzoylbenzyl)‐, N‐(1‐benzoylethyl)‐, N‐phenacyl‐, pyrazinium, 3‐bromoquinolinium, benzothiazolium, or p‐cyanopyridinium hexafluoroantimonates] were synthesized by the reaction of α‐benzoylbenzyl bromide, 2‐bromopropiophenone or phenacylbromide, and the corresponding N‐hetero aromatic compound, followed by anion exchange with KSbF6. These N‐phenacylammonium salts showed higher activity than previously reported N‐benzyl‐2‐cyanopyridinium hexafluoroantimonate in the photopolymerization of epoxides. Further, these N‐phenacylammonium salts served as photoradical and thermal cationic initiators as well as photocationic initiators. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3470–3476, 2004
Photosensitive polynorbornene based dielectric. II. Sensitivity and spatial resolution
Authors: Bai Yiqun , Chiniwalla Punit , Elce Edmund , Ann Bidstrup Allen Sue , Kohl Paul A.
Published: January 2004

Photodefinable poly(decylnorbornene‐co‐epoxidenorbornene) copolymer has been developed as a dielectric material for electronic packaging applications. The photodefinition properties of the polymer are affected by the copolymer composition, the concentration of photoactive compound and the process conditions. In particular, ultra‐high contrast conditions were found to promote the fabrication of vertical sidewall structures. For photodefined structures, the vertical sidewalls were obtained at specific formulations and process conditions. Under different conditions, non‐vertical features were observed. Rutherford backscattering analysis (RBS), X‐ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) were used to study the photodefinition properties. In this article, a mechanism based on the diffusion of photoactive compounds from the exposed area to the unexposed area is presented. The transport of photoactive compounds takes place through the free volume that results from solvent evaporation. The diffusion of the photoactive compounds to the surface of the polymer film results in a higher concentration of photogenerated acid at the surface. The movement of the photoactive compounds occurs in both the in‐plane and through‐plane directions. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3031–3039, 2004
Photosensitive polynorbornene based dielectric. I. Structure–property relationships
Authors: Bai Yiqun , Chiniwalla Punit , Elce Edmund , Shick Robert A. , Sperk James , Allen Sue Ann Bidstrup , Kohl Paul A.
Published: January 2004

In the microelectronics industry, the drive for increasing device speed, level of functionality and shrinking size has placed significant demands on the performance characteristics of polymer dielectrics. In this study, a negative acting, photodefinable dielectric formulation based on a copolymer of decylnorborne (decylNB) and epoxynorbornene (AGENB) was investigated for use in electronics packaging. The structure–property relations of this copolymer were investigated. Copolymer composition and processing conditions were shown to significantly affect the properties of the final polymer films. A lower content of AGENB results in lower moisture absorption, dielectric constant, modulus and residual stress, but it compromises multilayer capability. High crosslink density lowers the dielectric constant but increases the modulus and residual stress. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3023–3030, 2004
Methods to determine solubility parameters of polymers using inverse gas chromatography
Authors: Huang Jan‐Chan
Published: January 2004

Experimental values of the Flory–Huggins parameter, χ, between polymers and solvents, are frequently used to determine the solubility parameters of the polymers. A method using nonlinear curve fitting of RTχ/V was compared to the linear regression method commonly used. It was found that the formulas for the solubility parameter were the same, but the linear method produced a slightly different entropy term. The nonlinear method gave a lower correlation coefficient and wider confidence intervals and was more effective at distinguishing systems than the linear model. The effect of the deviation of probes in the solubility parameter model is discussed. Using probes with low solubility parameters to measure the polymer solubility parameter gave wider confidence intervals. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2894–2902, 2004
Photopolymerized low‐surface‐energy coatings based on a novel fluorinated ether acrylate
Authors: Shemper Bianca S. , Mathias Lon J.
Published: January 2004

The synthesis, characterization, and polymerization of a perfluoroalkyl ether substituted methacrylic acid (C8F7) were investigated. C8F7 was photopolymerized at different temperatures, higher double‐bond conversions being achieved at higher polymerization temperatures. The polymerization rates were fast in comparison with those of typical methacrylate esters. Thermogravimetric analysis of the obtained polymers showed thermal stabilities up to 270–290°C. The initial degradation at 200°C involved the loss of water and the partial loss of the perfluoroalcohol via the intramolecular formation of anhydride and lactone groups. The surface properties of coatings obtained with C8F7 coatings on various substrates were evaluated with water and hexadecane contact‐angle measurements, which confirmed that low‐surface‐energy polymeric coatings were obtained. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3301–3314, 2004
Two‐dimensional NMR studies of the cyclocopolymerization of sulfur dioxide and diethyl diallylmalonate
Authors: Tsai Jui‐Yi , Zhou Jing‐Lan , Sun Yahong , Shevlin Philip B.
Published: January 2004

Two‐dimensional NMR spectroscopic studies (HECTOR and NOESY) have confirmed that the copolymer of diethyl diallylmalonate with sulfur dioxide consists predominately of cis‐linked cyclopentane rings. When the cyclopolymerization is carried out at 81°C in acetonitrile, the ratio of cis to trans linkages is 4.3 : 1. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3477–3480, 2004
Preparation of water‐soluble chitosan
Authors: Lu Shaojie , Song Xuefeng , Cao Deyong , Chen Yiping , Yao Kangde
Published: January 2004

An improved method of preparing water soluble chitosan was studied by N‐acetylation with acetic anhydride. Its merits were a simple processing technique, very short reaction time, little agent, high molecular weight of the product, and good water solubility. This article not only discusses the effect of several factors, such as the amount of reactants, concentration of hydrogen ions in the solution, and solvent system, on N‐acetylation but also some influential factors on the water solubility of N‐acetylated chitosan. Experiments showed that the amount of acetic anhydride was the most important factor affecting the N‐acetylation degree of the chitosan. The effect of the means of adding materials and the amount of solvent on the reaction could not be ignored. The solubility of half N‐acetylated chitosan was not changed with an increase in the molecular weight in water, and the water solubility decreased with increasing molecular weight in the alkaline region. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3497–3503, 2004
NMR structural elucidation of amino resins
Authors: Angelatos A. S. , Burgar M. I. , Dunlop N. , Separovic F.
Published: January 2004

Urea formaldehyde, melamine formaldehyde, and melamine urea formaldehyde (MUF) are important industrial amino resins that find application in numerous diverse areas, most notably in the bonding of wood products. To understand the physical properties of these amino resins and, hence, optimize their performance, a knowledge of their chemical structure is necessary. This article reports the use of NMR spectroscopy to acquire this information in the solid and liquid states. 13C‐NMR experiments, supported and augmented by 1H‐NMR and 15N‐NMR results, showed that the two stages of resin synthesis, methylolation followed by condensation, occurred in each type of resin. However, in the various MUF samples analyzed, the second step appeared to be predominantly the self‐condensation of melamine and urea rather than the cocondensation of melamine and urea. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3504–3512, 2004
Synthesis, crosslinking, and characterization of energetic polymers through the azidification of glycidyl ether prepolymers
Authors: Kara Ş. , Öztürk E. , Polat K. , Alyürük K.
Published: January 2004

Low‐molecular‐weight atactic poly(propylene oxide) and poly(epichlorohydrin) (PECH) were chlorinated on average up to 4.42 chlorine atoms per repeat unit. A study of the products showed that chlorine substitution preferentially occurred on already chlorinated repeat units, yielding chlorine ‐rich and chlorine ‐poor sequences. As the extent of chlorine substitution increased, the glass‐transition temperature of the polymers markedly increased, and their solubility in most of the organic solvents drastically decreased. The chlorinated polymers were azidified with NaN3 in dimethyl sulfoxide solutions. An analysis showed that azide groups replaced 99.8–99.9% of the initially present chlorine atoms. As the azide content of the samples increased, initially opaque polymers become dark brown, and their solubility increased in water but decreased in organic solvents. Samples with approximately four or more azide groups per repeat unit were only soluble in dimethyl sulfoxide and water. The standard enthalpy of formation of the polymers became increasingly positive as the azide content increased. The enthalpy of formation of a sample with 4.42 N3/repeat unit was 6929 kJ/repeat unit, whereas this value was only 103 kJ/mol for classical GAP. An azidified sample from PECH (4.42 N3/repeat unit) was crosslinked with a commercial triisocyanide into a rubbery product. The density and ultimate tensile strength of the rubbery product were 1.44 g/cm3 and 4.84 MPa, and it swelled about 10% at 20°C in water.© 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91:3785–3790, 2004
Water and synthetic urine sorption capacity of cellulose‐based hydrogels under a compressive stress field
Authors: Sannino A. , Mensitieri G. , Nicolais L.
Published: January 2004

A new apparatus was developed and used to investigate the swelling behavior of crosslinked hydrophilic polymers under an applied load as a function of the absorbed weight in both water and water solutions. A model able to predict the material water uptake as a function of the isotropic compressive stress was also studied. Centrifugation tests were performed to measure the material retention capacity under load, in both water and synthetic urine. The polymers studied in the tests were from a particular class of superabsorbent hydrogels based on cellulose derivatives chemically crosslinked with divinyl sulfone. The hydrogels showed high sorption and retention capacity in both water and water solutions, both in the free state and under load, and significant variations were observed during the modulation of the dry sample porosity.© 2004 Wiley Periodicals, Inc.J Appl Polym Sci 91: 3791–3796, 2004
Effect of N‐methylimidazole and 3,5‐dimethylpyrazole ligands on the polymerization of di(2,6‐dichlorophenolato) Cu(II)/Co(II) complexes in the solid state
Authors: Baştürkmen M. , Hacaloğlu J. , Kısakürek D.
Published: January 2004

The polymerization of 2,6‐dichlorophenol (DCPH) was achieved through the thermal decomposition of copper complexes of DCPH with N‐methylimidazole (NMIz) and 3,5‐dimethylpyrazole (DMPz) ligands. Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), mass spectrometry, ultraviolet–visible spectroscopy, diffuse reflectance spectroscopy, magnetic susceptibility balance, electron spin resonance, X‐ray analysis, and elemental analysis were used to characterize the complexes. The polymerization was achieved either in the solid state or in the melt. The structural analyses were performed with FTIR and NMR spectroscopy analyses. The glass‐transition temperatures were determined by DSC, and the intrinsic viscosities were determined by viscosimetry. The effects of the temperature and time on the conversion percentage and viscosity of the polymers were examined. Varying the decomposition temperature during a 3‐h scan showed that the DMPz complex of Cu decomposed at lower temperatures than the NMIz complex, whereas the NMIz complex yielded a higher conversion to the polymer. Complexes of DCPH with NMIz and DMPz ligands produced 1,2‐ and 1,4‐addition products, respectively. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3797–3805, 2004
Comparison of the mechanical properties and interfacial interactions between talc, kaolin, and calcium carbonate filled polypropylene composites
Authors: Leong Y. W. , Abu Bakar M. B. , Ishak Z. A. Mohd. , Ariffin A. , Pukanszky B.
Published: January 2004

Three types of mineral fillers—talc, calcium carbonate (CaCO3), and kaolin (10–40 wt % filler loadings)—were compounded with polypropylene (PP) with a twin‐screw extruder. The composites were injection‐molded, and the effects of the filler loading on the mechanical, flow, and thermal properties for the three different types of filled composites were investigated. The aim was to compare their properties and to deduce prospective filler combinations that would yield hybrid PP composites in following studies. The results showed that in most cases, the strength and stiffness of the talc‐filled PP composites was significantly higher than those of the CaCO3‐ and kaolin‐filled PP composites. However, CaCO3, being a nonreactive filler, increased the toughness of PP. The kaolin‐filled PP composites also showed some improvement in terms of strength and stiffness, although the increases in these properties were not as significant as those of the talc‐filled PP composites. The effects of interfacial interactions between the fillers and PP on the mechanical properties were also evaluated with semiempirical equations. The nucleating ability of all three fillers was studied with differential scanning calorimetry, and the strongest nucleating agent of the three was talc, followed by CaCO3 and kaolin. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3315–3326, 2004
Mechanical and thermal properties of talc and calcium carbonate filled polypropylene hybrid composites
Authors: Leong Y. W. , Ishak Z. A. Mohd. , Ariffin A.
Published: January 2004

The main aim of this work was to study and compare the mechanical and thermal properties of hybrid polypropylene (PP) composites and single‐filler PP composites. With two main types of mineral fillers—calcium carbonate (CaCO3) and talc—PP composites of different filler weight ratios (talc/CaCO3) were compounded with a twin‐screw extruder and then injection‐molded into dumbbell specimens with an injection‐molding machine. Tensile, flexural, and impact tests were performed to determine and compare the mechanical properties of the hybrid and single‐filler PP composites. A synergistic hybridization effect was successfully achieved; the flexural strength and impact strength were highest among the hybrids when the PP/talc/CaCO3 weight ratio was 70:15:15. The nucleating ability of the fillers and its effects on the mechanical properties were also studied with differential scanning calorimetry. Because of the influence of talc as the main nucleating agent, the hybrid fillers showed significant improvements in terms of the nucleating ability, and this contributed to the increase in or retention of the mechanical properties of the hybrid composites. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3327–3336, 2004
pH‐reversible magnetic gel with a biodegradable polymer
Authors: Chatterjee Jhunu , Haik Yousef , Chen Ching‐Jen
Published: January 2004

Polymer gels that react to external stimuli, such as pH, temperature, and electromagnetic fields, are an important class of materials. Such materials have pharmaceutical, industrial, and biomedical applications. Our intention in this study was to synthesize a stimuli‐responsive polymer gel with a biodegradable polymer. However, the chemical crosslinker, divinyl sulfone, which is most widely used for the crosslinking of this type of material, is highly toxic in nature. To overcome this problem, a reversible magnetic gel was synthesized with hydroxy propyl cellulose (HPC) and maghemite at pH 13 without with a chemical crosslinker. With a decrease in pH from 13 to 9, the gel formed a homogeneous dispersion of HPC particles with maghemite in it. This process was a reversible physical gelation where the crosslinks of the network had a physical origin (in this case, hydrogen bonding) and, therefore, were sensitive to variations in pH. When this physically prepared gel was compared with the chemically crosslinked one, no significant differences in structural properties were noted. At higher pH values, the gel was formed due to weak intermolecular hydrogen bonding, as observed by the broadening of the IR band in both the magnetic and nonmagnetic gels. Transmission electron micrographs also showed no significant difference in the gel morphology. Differential scanning calorimetry showed an increase in melting temperature for the gel sample compared to that of pure HPC. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3337–3341, 2004
Devulcanization of nitrile butadiene rubber in nitrobenzene
Authors: Masaki Kohji , Ohkawara Shin‐Ichi , Hirano Tomohiro , Seno Makiko , Sato Tsuneyuki
Published: January 2004

Sulfur‐crosslinked nitrile butadiene rubber (s‐NBR) was found to be devulcanized when it was heated with nitrobenzene at 200°C for 3 h. The tetrahydrofuran (THF)‐soluble fraction from s‐NBR heated with nitrobenzene was purified by reprecipitation with THF/n‐hexane, chloroform/n‐hexane, and THF/n‐hexane systems and was then characterized by means of Fourier transform infrared (FTIR) spectroscopy, 1H‐NMR, gel permeation chromatography, dynamic thermogravimetry/differential thermal analysis (DTA), and differential scanning calorimetry (DSC). FTIR and 1H‐NMR results revealed that the THF‐soluble fraction contained aromatic rings derived from nitrobenzene. Furthermore, the molecular weight of the THF‐soluble fraction was much lower than that of the parent noncrosslinked poly(acrylonitrile‐co‐butadiene). Although the weight loss of THF‐soluble fraction began at a lower temperature than that of the nonheated original nitrile butadiene rubber, the residual weight at 700°C tended to be higher for the former. This tendency became more marked with increasing time of heat treatment with nitrobenzene. The DSC‐determined glass‐transition temperature of the THF‐soluble fraction was higher than that of the original s‐NBR. To elucidate the devulcanization mechanism, we investigated two types of model reactions; one was the reaction of diphenyl disulfide with nitrobenzene, and the other was the reaction of polybutadiene with nitrobenzene. The former reaction, carried out at 250°C in diphenyl ether, yielded diphenyl sulfide with a loss of diphenyl disulfide and nitrobenzene. The use of a higher molar ratio of nitrobenzene to diphenyl disulfide resulted in a depression of diphenyl sulfide formation. The reaction of p‐chloronitrobenzene with diphenyl disulfide also gave diphenyl sulfide. The reaction of polybutadiene with nitrobenzene at 200°C resulted in the backbone scission of the polymer. The THF‐soluble solid product of the latter model reaction was found by FTIR and 1H‐NMR to contain aromatic rings derived from nitrobenzene. The devulcanization mechanism is discussed on the basis of a comparison of the results of the model reactions with those of the s‐NBR devulcanization. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3342–3353, 2004
Adsorption of color dyestuffs on polyurethane–chitosan blends
Authors: Shih Chung‐Yang , Chen Chien‐Wen , Huang Kuo‐Shien
Published: January 2004

This study made use of poly(ethylene glycol) (PEG) samples of different molecular weights, which were reacted with a diisocyanate ester, and an anion center for the synthesis of polyurethane (PU), which was then mixed with chitosan to form a polymer adsorbent. It was tested for the determination of its adsorption toward acidic dyestuffs under various conditions. Our results showed that under all the tested conditions, the blended polymer adsorbent possessed a better adsorbing ability than chitosan by itself, and the degree of adsorption varied positively as the adsorbent concentration, ambient temperature, and contact time increased. Furthermore, the addition of PU remarkably increased the adsorption efficiency, whereas PEG with a greater molecular weight yielded a better adsorption performance. As for the dyestuffs, the red one surpassed the others in adsorption efficiency. Finally, a 5 mg/mL concentration of the adsorbent solution, a temperature of 45°C, and a contact time of 15 min gave fairly good adsorption results. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3991–3998, 2004
Dyeing properties of novel regenerated cellulosic fibers
Authors: Koh Joonseok , Soo Kim Ik , Soo Kim Sung , Sub Shim Woo , Pil Kim Jae , Yeop Kwak Seung , Wook Chun Sang , Ku Kwon Yong
Published: January 2004

Two types of direct dyes (disazo and phthalocyanine) were applied to regular viscose rayon and a new regenerated cellulosic fiber (enVix), which was prepared from cellulose acetate fiber through the hydrolysis of acetyl groups, and their dyeing and fastness properties were compared. enVix exhibited better dyeability and fastness than regular viscose rayon. This was explained by the differences in the supramolecular structures of the two fibers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3481–3488, 2004
Application of the fractional derivative theory to the estimation of the end‐to‐end distance of polycarbonate chains
Authors: Kozlov G. V. , Dolbin I. V. , Shogenov V. Kh. , Zaikov G. E.
Published: January 2004

This study has led to two main conclusions. First, fractional derivation can be used to calculate the average end‐to‐end distance of a polymeric chain as precisely as other existing computational techniques. Second, knowledge of the changes in the molecular characteristics of a polymeric chain is needed for the correct calculation of the indicated parameters. In other words, one should take into consideration the dynamics when the structure of a macromolecular coil is varied. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3765–3768, 2004
Immobilization of glucose oxidase onto electrochemically prepared poly(aniline‐co‐fluoroaniline) films
Authors: Sharma Amit L. , Singhal Rahul , Kumar Arun , Rajesh  , Pande Krishan K. , Malhotra Bansi D.
Published: January 2004

Poly(aniline‐co‐fluoroaniline) [poly(An‐FAn)] films were electrochemically deposited on indium tin oxide glass plates. The characterization of these conducting copolymer films was carried out with ultraviolet–visible and Fourier transform infrared techniques. The enzyme glucose oxidase (GOX) was immobilized onto the conducting poly(An‐FAn) films by a physical adsorption method. Amperometric response experiments carried out with poly(An‐FAn)/GOX films revealed linearity from 0.5 to 22 mM glucose, and the Michaelis–Menten constant was found to be about 23.5 mM. The shelf life of these poly(An‐FAn)/GOX electrodes was measured to be about 15 days, and the electrodes were stable up to 45°C. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3999–4006, 2004
Preparation and characterization of an enzyme electrode based on cholesterol esterase and cholesterol oxidase immobilized onto conducting polypyrrole films
Authors: Singh Suman , Chaubey Asha , Malhotra B. D.
Published: January 2004

Cholesterol esterase (ChEt) and cholesterol oxidase (ChOx) enzymes were entrapped within polypyrrole (PPy) films on a platinum disc electrode during electrochemical polymerization. The characteristics of the PPy/ChEt/ChOx enzyme electrode thus prepared were investigated as a function of the time, pH, temperature, and concentration of cholesteryl palmitate by a spectrophotometric method. PPy/ChEt/ChOx electrodes can be used for the estimation of cholesteryl palmitate concentrations from 1 to 8 mM, can be used least 10 times, and have a shelf life of about 1 month at 4–10°C. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3769–3773, 2004
Effects of poly(methyl methacrylate)‐based low‐profile additives on the properties of cured unsaturated polyester resins. I. Miscibility, curing behavior, and glass‐transition temperatures
Authors: Dong Jyh‐Ping , Huang Jyh‐Gau , Lee Fuh‐Huah , Roan Jiunn‐Wei , Huang Yan‐Jyi
Published: January 2004

The effects of three series of self‐synthesized poly(methyl methacrylate) (PMMA)‐based low‐profile additives (LPAs), including PMMA, poly(methyl methacrylate‐co‐butyl acrylate), and poly(methyl methacrylate‐co‐butyl acrylate‐co‐maleic anhydride), with different chemical structures and MWs on the miscibility, cured‐sample morphology, curing kinetics, and glass‐transition temperatures for styrene (ST)/unsaturated polyester (UP) resin/LPA ternary systems were investigated by group contribution methods, scanning electron microscopy, differential scanning calorimetry (DSC), and dynamic mechanical analysis, respectively. Before curing at room temperature, the degree of phase separation for the ST/UP/LPA systems was generally explainable by the calculated polarity difference per unit volume between the UP resin and LPA. During curing at 110°C, the compatibility of the ST/UP/LPA systems, as revealed by cured‐sample morphology, was judged from the relative magnitude of the DSC peak reaction rate and the broadness of the peak. On the basis of Takayanagi's mechanical models, the effects of LPA on the final cure conversion and the glass‐transition temperature in the major continuous phase of ST‐crosslinked polyester for the ST/UP/LPA systems was also examined. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3369–3387, 2004
Effects of poly(methyl methacrylate)‐based low‐profile additives on the properties of cured unsaturated polyester resins. II. Volume shrinkage characteristics and internal pigmentability
Authors: Dong Jyh‐Ping , Huang Jyh‐Gau , Lee Fuh‐Huah , Roan Jiunn‐Wei , Huang Yan‐Jyi
Published: January 2004

The effects of three series of self‐synthesized poly(methyl methacrylate) (PMMA)‐based low‐profile additives (LPAs), including PMMA, poly(methyl methacrylate‐co‐butyl acrylate), and poly(methyl methacrylate‐co‐butyl acrylate‐co‐maleic anhydride) with different chemical structures and MWs on the volume shrinkage characteristics and internal pigmentability for low‐shrink unsaturated polyester (UP) resins during curing were investigated by an integrated approach of static phase characteristics of the ternary styrene (ST)/UP/LPA system, reaction kinetics, cured‐sample morphology, microvoid formation, and property measurements. The relative volume fraction of microvoids generated during the cure was controlled by the stiffness of the UP resin used, the compatibility of the uncured ST/UP/LPA systems, and the glass‐transition temperature of the LPAs used. On the basis of the Takayanagi mechanical model, the LPA mechanism on volume shrinkage control, which accounted for phase separation and microvoid formation, and factors leading to both a good volume shrinkage control and acceptable internal pigmentability for the molded parts are discussed. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3388–3397, 2004
Effects of the moisture and fiber content on the mechanical properties of biodegradable polymer–sisal fiber biocomposites
Authors: Alvarez V. A. , Fraga A. N. , Vázquez A.
Published: January 2004

The matrix of the composites that were used in this work was a commercial blend based on starch and cellulose derivatives. The biodegradable polymer was reinforced by short‐sisal fibers with a range in fiber content of 5–15 wt %. The effects of humidity on the diffusion coefficients, equilibrium moisture content, and mechanical properties were studied. Equations obtained from microscopic mass balances for diffusion in solids were used to predict the absorbed humidity in both components (the sisal fibers and biodegradable polymer) and in the composites as a function of time. Different model predictions of the composite diffusion coefficients as a function of the filler concentration were also examined, and they were found to be in agreement with the experimental results. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 4007–4016, 2004
Experimental verification of failure of Amontons' law in polymeric textiles
Authors: Ramkumar S. S. , Rajanala R. , Parameswaran S. , Paige R. , Shaw A. , Shelly D. C. , Anderson T. A. , Cobb G. P. , Mahmud R. , Roedel C. , Tock R. W.
Published: January 2004

The dynamic friction of a variety of textile materials was studied and was experimentally proven that the frictional behavior of textile materials do not obey the Amontons' basic law of friction (F/N = μ). Both woven and nonwoven materials with different fiber content and constructional features were used in the study. Results show that the dynamic friction–normal load relationship is not a straight line passing through origin. A statistical approach has been followed to prove the significance of the deviation from the Amontons' law. To the authors' best knowledge, the work reported in this article has for the first time experimentally proven the failure of Amontons' basic law of friction for polymeric textiles, using a novel approach. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3879–3885, 2004
Chemical and mechanical properties of butyl methacrylate grafted wool fiber
Authors: Meng Xiang‐Ying
Published: January 2004

Because polymer‐grafted wool fibers had been reported to have better functional performance, a K2S2O8–NaHSO3 redox system was used as the initiator for the grafting copolymerization of butyl methacrylate (BMA) onto wool fibers. Grafted samples of wool‐g‐BMA with different grafting percentages (5.2–25.86) were obtained through variations in the monomer concentration in the reaction system. The evidence for grafting was provided by scanning electron microscopy and infrared spectroscopy. After the grafting, the moisture retention of the wool‐g‐BMA fibers decreased slightly. Optical measurements showed that the birefringence decreased, indicating a lower degree of molecular orientation of the wool‐g‐BMA fibers. The tensile strength increased as the grafting percentage increased. Beyond an 18–25% grafting percentage, the elongation at break decreased, and this indicated a reduction of the elastic deformation, which meant that the flexibility of the modified fibers may have deteriorated. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3813–3817, 2004
γ‐Radiation‐treated starch/poly(vinyl alcohol) composites for cotton fabric sizing
Authors: El‐Naggar Abdel‐Wahab M. , Senna Magdy M. , Khalil Salwa A.
Published: January 2004

Films of different composites based essentially on maize starch (MS)/poly(vinyl alcohol) (PVA) blends were prepared by the solution‐casting technique and subjected to various doses (20–100 kGy) of γ‐radiation. The MS/PVA blends were modified by the addition of glycerol (GY) and a graft copolymer (GP) of MS with acrylamide separately or together with the polymer blend solutions before casting. The γ‐treated composites were evaluated in terms of the apparent viscosity and their suitability as sizing materials for cotton fabrics. The sizeability of these composites for cotton fabrics was assessed in terms of the size removal percentage at different temperatures and the effect on the tensile properties and water absorption. The change in the apparent viscosity with the shear rate showed that γ‐irradiation improved the behavior of MS/PVA blends and their composites with GY or GP as a sizing material for cotton fabrics. Moreover, the improvement in the tensile mechanical properties of the sized cotton fabrics with these composites gave further support to this finding. The results for the size removal percentage and water adsorption indicated that these composites could be removed by washing at 70°C for 10 min. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3818–3826, 2004
Curing and mechanical characterization of a soy‐based epoxy resin system
Authors: Zhu Jiang , Chandrashekhara K. , Flanigan Virgil , Kapila Shubhender
Published: January 2004

A potentially inexpensive alternative epoxy resin system based on soybean oil has been developed for polymer composite applications. Epoxidized methyl soyate (EMS) and epoxidized allyl soyate (EAS) have been synthesized at the University of Missouri–Rolla. These materials consist of mixtures of epoxidized fatty acid esters. The epoxidized soy‐based resins provide better intermolecular crosslinking and yield materials that are stronger than materials obtained with commercially available epoxidized soybean oil (ESO). The curing behavior and glass transition have been monitored with differential scanning calorimetry. Neat resin test samples have been fabricated from resin systems containing various amounts of EMS, EAS, and ESO. Standardized tests have shown that the addition of EAS enhances the tensile and flexural properties of the base epoxy resin system. Therefore, epoxidized soy ester additives hold great potential for environmentally friendly and lower cost raw materials for the fabrication of epoxy composites for structural applications. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3513–3518, 2004
Nonlinear viscoelastic model for the prediction of double yielding in a linear low‐density polyethylene film
Authors: Spathis G. , Kontou E.
Published: January 2004

Tensile testing and tensile creep experiments for linear low‐density polyethylene in a thin‐film form were examined and analyzed in terms of a nonlinear viscoelastic model. The proposed model, based on two distinct thermally activated rate processes (Eyring models), was proved to describe the double‐yield‐point tensile behavior of the material tested. The required model parameters were evaluated from the corresponding creep‐strain curves, and this revealed the relationship between the main aspects of the inelastic behavior of polymers, that is, the monotonic loading and creep response. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3519–3527, 2004
PMMA/silica nanocomposite studies: Synthesis and properties
Authors: Yang Feng , Nelson Gordon L.
Published: January 2004

Polymethylmethacrylate (PMMA)/silica nanocomposites are prepared by solution polymerization in this project and the resulting materials are subjected to characterization to evaluate thermal, mechanical, and fire properties. IR results show that both (3‐acryloxypropyl)methydimethoxy‐silane (APMDMOS) and (3‐acryloxypropyl)trimethoxysilane (APTMOS) can serve as reagents for the surface modification of silica, while APTMOS performed better than APMDMOS for the modification of the silica surface. Mechanical properties of PMMA/silica nanocomposites prepared by solution blending showed decreased tensile strength and elongation at break, while materials from solution polymerization performed better than PMMA itself. Moreover, all prepared samples have shown improved thermal stabilities versus PMMA. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3844–3850, 2004
Characterization of i‐PP shear‐induced crystallization layers developed in a slit die
Authors: Farah Marcelo , Bretas Rosario E. S.
Published: January 2004

In this work, the shear‐induced crystalline layers of isotactic polypropylene (i‐PP), developed in a slit die, were characterized by different techniques. Rheological studies made in a strain‐controlled rheometer, at different crystallization temperatures,Tc, allowed us to observe that the induction time for the beginning of the shear‐induced crystallization,ti, decreased as the shear rate increased, whereas at a given shear rate, the higher theTc, the higher theti. The thickness of the shear‐induced crystallized layer, after extrusion through the slit die, was found to decrease with the increase of the die temperature,Td, at a given flow rate,Q, and to increase with the increase inQ, at a givenTd. Regarding the die length, it was found that only atTd= 169°C, the thickness of this layer increased with the length. By polarized light optical microscopy (PLOM), five different crystalline layers were observed along the thickness of the sample. By scanning and transmission electron microscopy (SEM and TEM), respectively, and wide‐angle X‐rays (WAXS), it was found that layer 1, the nearest to the wall, was formed mainly by very small and oriented α‐crystallites, while layer 2 was mainly composed of β‐crystallites; also it was found that the amount of the β‐phase decreased as the shear rate decreased. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3528–3541, 2004
Synthesis of nanophase‐separated poly(urethane‐co‐acrylic acid) network films and their application for magnetic nanoparticle synthesis
Authors: Kim Ju‐Young , Shin Dong‐Hyun , Ryu Jee‐Hyun , Choi Gyung‐Hyun , Suh Kyung‐Do
Published: January 2004

Poly(urethane‐co‐acrylic acid) films were synthesized by the copolymerization of urethane acrylate nonionomer (UAN) and acrylic acid (AA) under different conditions. Poly(urethane‐co‐acrylic acid) films exhibited very different mechanical properties, attributed to the microstructural difference with the type of solvents used in the film preparation. The film synthesized using UAN/AA/water mixture had a relatively highly nanophase separated structure compared to that of the other films prepared using UAN/AA/dioxane mixture, resulting in higher mechanical property and glass‐transition temperature. The nanostructural differences could be also confirmed by atomic force microscopy measurements. Magnetic nanocomposite films synthesized based on UAN/AA/water and UAN/AA/dioxane mixtures showed different sizes of magnetic nanoparticles, attributed to the differences of size of hydrophilic nanodomains. The higher the degree of nanophase separation within poly(urethane‐co‐acrylic acid) films, the larger the size of hydrophilic nanodomains, resulting in formation of larger nanoparticles. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3549–3556, 2004
Microscopic analysis of aroma chemical distribution on fibers. I. cis‐3‐hexenyl salicylate
Authors: Liu Haiqing , Obendorf S. Kay , Young Timothy J. , Incorvia Michael J.
Published: January 2004

The distribution of aroma chemical cis‐3‐hexenyl salicylate, on both longitudinal and cross‐sectional fiber directions, was identified through backscattered electron microscopy and X‐ray microanalysis including X‐ray spectrum and X‐ray map. Three fibers—cotton, lyocell, and polyester [poly(ethylene terephthalate) (PET)]—were used as substrates to evaluate the influence of fiber physical/chemical nature on the distribution of cis‐3‐hexenyl salicylate. It was found that the distribution of cis‐3‐hexenyl salicylate on the external and internal fiber surfaces correlated strongly with the chemical structure, roughness, and both pore and capillary structure of the textiles. cis‐3‐Hexenyl salicylate distributed through the whole cotton fiber cross section with higher concentrations in lumen and crenulations, whereas it distributed relatively uniformly in the surface and cross section of lyocell fiber. This is believed to relate to the macro‐ and micropores, macroscopic roughness, and the presence of a larger number of polar groups for these cellulose fibers. In contrast, cis‐3‐hexenyl salicylate accumulated at a few spots on the fiber surfaces of PET and in interfiber spaces of closely packed fibers, attributed to lower polarity, round cross‐sectional shape, smooth surfaces, and fewer voids of the PET fiber structure. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3557–3564, 2004
Effect of polyethylene glycol molecular weights and concentrations on polyethersulfone hollow fiber ultrafiltration membranes
Authors: Xu Zhen‐Liang , Qusay F. Alsalhy
Published: January 2004

Polyethersulfone (PES) hollow‐fiber membranes were fabricated using poly(ethyleneglycol) (PEG) with different molecular weights (MW = PEG200, PEG600, PEG2000, PEG6000, and PEG10000) and poly(vinyl pyrrolidone) PVP40000 as additives and N‐methyl‐2‐pyrrolidone (NMP) as a solvent. Asymmetric hollow‐fiber membranes were spun by a wet phase‐inversion method from 25 wt % solids of 20 : 5 : 75 (weight ratio) PES/PEG/NMP or 18 : 7 : 75 of PES/(PEG600 + PVP40000)/NMP solutions, whereas both the bore fluid and the external coagulant were water. Effects of PEG molecular weights and PEG600 concentrations in the dope solution on separation properties, morphology, and mechanical properties of PES hollow‐fiber membranes were investigated. The membrane structures of PES hollow‐fiber membranes including cross section, external surface, and internal surface were characterized by scanning electron microscopy and the mechanical properties of PES hollow‐fiber membranes were discussed. Bovine serum albumin (BSA, MW 67,000), chicken egg albumin (CEA, MW 45,000), and lysozyme (MW 14,400) were used for the measurement of rejection. It was found that with an increase of PEG molecular weights from 200 to 10,000 in the dope solution, membrane structures were changed from double‐layer fingerlike structure to voids in the shape of spheres or ellipsoids; moreover, there were crack phenomena on the internal surfaces and external surfaces of PES hollow‐fiber membranes, pure water permeation fluxes increased from 22.0 to 64.0 L m−2 h−1 bar−1, rejections of three protein for PES/PEG hollow‐fiber membranes were not significant, and changes in mechanical properties were decreased. Besides, with a decrease of PEG600 concentrations in the dope solution, permeation flux and elongation at break decreased, whereas the addition of PVP40000 in the dope solution resulted in more smooth surfaces (internal or external) of PES/(PEG600 + PVP40000) hollow‐fiber membranes than those of PES/PEG hollow‐fiber membranes. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3398–3407, 2004
Influence of urea on the coloring ability of a low‐temperature coloring method of keratin fibers using polyethyleneimine
Authors: Kuzuhara A.
Published: January 2004

For the purpose of improving the coloring ability of keratin fibers at a lower temperature, we investigated the influence of urea on the coloring ability of a low‐temperature coloring method using polyethyleneimine (PEI) as a counter ion reagent (the human hair was previously treated with a PEI solution, and then was colored with acid dye). The coloring and color fastness to shampooing of the hair pretreated with a PEI solution containing urea clearly improved compared with those pretreated with a PEI solution not containing urea. Also, we prepared cross‐sectional samples of the treated hair and investigated the penetration of PEI and Orange II into human hair by optical microscopy. The results showed that the penetration of PEI and Orange II into human hair pretreated with a PEI solution that contained urea clearly increased compared with those pretreated with a PEI solution that did not contain urea. From these experiments, we concluded that urea acts as a penetration accelerator for PEI; and PEI, which penetrates deeper into human hair by adding urea, exerts counter ionization on Orange II, thus increasing the penetration of Orange II into human hair and thereby improving the coloring ability. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3827–3834, 2004
Friction and scratch resistance of polyamide 6 modified with ionomeric ethylene/methacrylic acid copolymer
Authors: Jaklewicz Magdalena , Litak Antoni , Ostoja‐Starzewski Martin
Published: January 2004

Ethylene/methacrylic acid copolymer Surlyn® 9020 (SU) was used to reduce the crystallinity of polyamide 6 (PA6). Differential scanning calorimetry was used to calculate the change in crystallinity of a modified polymer: four cases of SU weight fractions (5, 15, 20, and 30%) were considered. The fracture morphology was studied by use of scanning electron microscopy. With the increasing fraction of SU the structure transformed into a fine crystalline one. The effect of reduction in crystalline fraction on friction and scratch resistance of PA6 was investigated. The static and dynamic coefficients of friction decreased with respect to the increase in weight fraction of SU. With the addition of SU, the scratch resistance was found to decrease as well, whereas the healing (i.e., recovery of material after a scratch was made) of the material was found to increase. SU hindered crystallization of PA6, and with higher content of SU plastification of material occurred. Results from thermomechanical tests confirmed that conclusion: the Young's modulus E decreases and the thermal expansion coefficient αL increases with the addition of SU. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3866–3870, 2004
Effect of acetonitrile pretreatment on the physicochemical behavior of 100% polyester fabric
Authors: Muralidharan B. , Mathanmohan T. , Ethiraj J.
Published: January 2004

Acetonitrile pretreatment of 100% poly(ethylene terephthalate) fabric was performed over different lengths of time. The influence of solvent treatment on the dyeing behavior and some of the physicochemical properties were investigated. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3871–3878, 2004
Vacuum ultraviolet–induced photochemical nitriding of polyolefin surfaces
Authors: Truica‐Marasescu F. , Wertheimer M. R.
Published: January 2004

Film samples of two very pure polyolefins, low‐density polyethylene (LDPE) and biaxially oriented polypropylene (BOPP), were surface‐modified by vacuum ultraviolet (VUV) photochemistry in low‐pressure ammonia. The influence of experimental conditions such as wavelength and intensity (photon flux) of the VUV radiation, ammonia pressure, and treatment duration, as well as the mechanisms involved in the surface modification were discussed. Changes in the surface energy and chemistry were investigated using suitable techniques like contact angle goniometry (surface energy) measurements, X‐ray photoelectron spectroscopy (XPS), attenuated total reflectance infrared spectroscopy, and time‐of‐flight secondary ion mass spectroscopy. We show that chemically bonded nitrogen concentrations [N], up to 25%, can be achieved on the polymer surfaces by VUV photochemistry, and that N is predominantly bonded as amine groups, thus leading to an important increase in the surface energy of treated samples. Finally, XPS, surface energy measurements, and atomic force microscopy were used to characterize possible degradation of the polymer surfaces during the VUV treatments. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3886–3898, 2004