bluuebunny/crossref_metadata_2025_split 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

AbstractSyndiotactic 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

AbstractNovel 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

AbstractPhotodefinable 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

AbstractIn 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

AbstractExperimental 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

AbstractThe 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

AbstractTwo‐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

AbstractAn 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

AbstractUrea 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

AbstractLow‐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

AbstractA 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

AbstractThe 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

AbstractThree 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

AbstractThe 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

AbstractPolymer 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

AbstractSulfur‐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

AbstractThis 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

AbstractTwo 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

AbstractThis 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