bluuebunny/crossref_metadata_2025 huggingface dataset:
Indentation responses of a graded zirconium phosphate–filled epoxy resin
Authors: Low I. M. , Shi C. , Hussain M. , Yamaguch S. , Niihara K.
Published: October 2004

The effects of load and time on the Vickers indentation responses of a graded zirconium phosphate (ZP)–filled epoxy resin are described. The hardness of this material is dependent on the concentration of ZP dispersed within the epoxy matrix. In the region poor in ZP, the hardness response is independent of load. In contrast, the hardness response in the region rich in ZP is profoundly load‐dependent as a combined result of particle agglomeration and an indentation‐size effect. When compared with the ZP‐rich‐epoxy, the ZP‐poor epoxy exhibits a larger creep and a more pronounced elastic recovery in the Vickers impression. The nature and degree of deformation in the vicinity of Vickers contacts are also studied. During indentation the ZP‐rich epoxy exhibits no contact‐induced cracks but displays microscale plasticity, which can be associated with intergrain sliding, debonding, and grain push‐out. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 931–935, 2001
Synthesis of silicone–acrylic resins and their applications to superweatherable coatings
Authors: Park Hong‐Soo , Yang In‐Mo , Wu Jong‐Pyo , Kim Myung‐Soo , Hahm Hyun‐Sik , Kim Seong‐Kil , Rhee Hee‐Woo
Published: October 2004

Silicone–acrylic resins were synthesized to prepare superweatherable paints for building materials. The raw materials used were n‐butyl acrylate, methyl methacrylate, and n‐butyl methacrylate as acrylic monomers and 3‐methacryloxypropyltrimethoxysilane (MPTS) as a silicone monomer reactive with the acrylic monomers. Acrylic copolymers were synthesized such that their glass‐transition temperatures were adjusted to 30°C and their MPTS contents were varied to 10, 20, and 30 wt %. As the content of silicone and MPTS increased, average molecular weight and viscosity increased, and thermal stability at high temperatures improved. When we tested the properties of coatings by blending the synthesized silicone–acrylic resins with a white pigment, adhesion was superior with various substrates, and their properties were suitable on the whole. Weatherability was tested by an outdoor exposure test with a weather‐ometer and an accelerated weathering tester, and their results showed that silicone–acrylic resin composed of 30 wt % MPTS was a superweatherable coating. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1614–1623, 2001
Measurement of water vapor transmission rate in highly permeable films
Authors: Hu Y. , Topolkaraev V. , Hiltner A. , Baer E.
Published: October 2004

Measurements of water vapor transmission rate (WVTR) are often based on the wet cup method described by ASTM E 96‐95. In attempting to compare the performance of thin polymer films with moderate to high water vapor permeability, it was observed experimentally that the ASTM method did not give reliable results for highly permeable films. In particular, the WVTR depended on film thickness and the ratio of film area to water surface area. It was determined that the high water vapor flux through the more permeable films caused a reduction in the driving force for water vapor transmission, that is, the relative humidity at the inner surface of the film. Consequently, the WVTR was underestimated. Comparisons based on a small area ratio and a constant small‐flux condition were considered as alternative approaches for evaluating performance using the wet cup method. The constant flux approach produced the best correlation with WVTR that was measured with a commercial instrument. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1624–1633, 2001
Preparation of PVDF hollow‐fiber membranes via immersion precipitation
Authors: Kong Jianfeng , Li K.
Published: October 2004

Porous polyvinylidene fluoride (PVDF) hollow‐fiber membranes with high porosity were fabricated using the immersion precipitation method. Dimethylacetamide (DMAc) and N‐methyl‐2‐pyrrolidone (NMP) were used as solvent, respectively. In addition, polyvinylpyrrolidone (PVP), lithium chloride, and organic acids were employed as nonsolvent additives. The effects of the internal and external coagulation mediums on the resulting membrane properties were also investigated. The resulting hollow‐fiber membranes were characterized in terms of maximum pore radius, mean pore radius, effective surface porosity as well as wetting pressure. The structures of the prepared hollow fibers were examined using a scanning electron microscope. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1643–1653, 2001
Melamine salts as hardeners for urea formaldehyde resins
Authors: Weinstabl Andrea , Binder Wolfgang H. , Gruber Heinrich , Kantner Wolfgang
Published: October 2004

Various salts derived from melamine and organic acids were prepared and used as melamine substitutes for melamine urea formaldehyde (MUF) resins. The synthesis of these melamine salts and a detailed characterization of their stoichiometry are described. All salts form 1 : 1 or 1 : 2 stoichiometries in a homogeneous reaction. They crystallize during cooling of the hot and diluted reaction mixture. Both 13C–NMR and 15N–NMR data are reported and point toward the formation of real ionic structures. Most salts have higher water solubility than that of pure melamine and are tested for their ability to substitute melamine in MUF resins. The mechanical and chemical properties of plywood panels made up of traditional MUF resins and mixtures of UF resins with melamine salts are investigated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1654–1661, 2001
Chain orientation resulting from the crystallization under strain of poly(ϵ‐caprolactone) in miscible blends with poly(styrene‐co‐maleic anhydride)
Authors: Morin Dominique , Zhao Yue , Prud'Homme Robert E.
Published: October 2004

Amorphous miscible blends of poly(ϵ‐caprolactone) (PCL) with a random copolymer of styrene–maleic anhydride (SMA) were stretched at room temperature and the crystallization of PCL was allowed to develop under strain. The crystallization of PCL, from oriented amorphous chains, leads to macroscopic crystalline chain orientation. Using infrared dichroism and wide‐angle X‐ray scattering techniques, it was found that the resultant crystalline orientation of PCL is always parallel to the strain direction, regardless of the experimental conditions, which is in contrast with the PCL/poly(vinyl chloride) blend, where both parallel and perpendicular chain orientations can be induced. Furthermore, the degree of crystalline orientation of PCL is influenced by the initial stretching‐induced amorphous chain orientation of the system. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1683–1690, 2001
Impact fracture behavior of ethylene ionomer and structural change after stretching
Authors: Akimoto Hideo , Kanazawa Toshiaki , Yamada Masanobu , Matsuda Satoshi , Shonaike Gabriel O. , Murakami Atsushi
Published: October 2004

We carried out tensile impact test and very low speed tensile test on ethylene‐based Ionomers (E/15wt %MAA) to clarify the relation between impact toughness and high‐ordered structure. We also studied the changes in high‐ordered structure under deformation by observing Differential Scanning Calorimetory (DSC) and Small‐Angle X‐ray Scattering (SAXS) of fractured surface. Na Ionomers showed ductile fracture in both high speed tensile impact (3 m/s) and very low speed tensile (2 mm/min). The disappearance of secondary melting point (Ti) in Na Ionomers was due to the destruction of ordered structure surrounding the ionic aggregate. Similar behavior was observed in 60% (or less) neutralized Zn Ionomers. However, 80% neutralized Zn Ionomer showed brittle failure in high‐speed tensile impact, and Ti did not disappear. SAXS studies of Na and Zn Ionomers after fracture, show no change both after molding (no aging) and after aging. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1712–1720, 2001
Miniemulsion copolymerization of n‐butyl methacrylate with crosslinking monomers
Authors: Ghazaly H. Mohd. , Daniels E. S. , Dimonie V. L. , Klein A. , El‐Aasser M. S.
Published: October 2004

Miniemulsion copolymerization of n‐butyl methacrylate and crosslinking monomers such as a macromonomer crosslinker (Mac), ethylene glycol dimethacrylate (EGDMA), or an aliphatic urethane acrylate macromonomer (AUA) was utilized to obtain crosslinked latex particles. The crosslinking monomers were added at 0.2 mol %, on the basis of the amount of n‐butyl methacrylate utilized in a polymerization. The development of the gel content during the copolymerization reaction differs depending on the type of the crosslinking monomer. In addition to the crosslinking reactions between the n‐butyl methacrylate and the crosslinking monomers, other kinetic events, such as microphase separation, may have occurred, giving rise to different particle morphologies, dependent on the type of initiator used (i.e., oil‐soluble or water‐soluble). © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1721–1730, 2001
Development of graft copolymer flocculating agents based on hydroxypropyl guar gum and acrylamide
Authors: Nayak B. R. , Singh R. P.
Published: October 2004

Graft copolymers of hydroxypropyl guar gum (HPG) with polyacrylamide (PAM) have been synthesized using a ceric ion‐induced solution polymerization technique at 28°C. Six graft copolymers have been synthesized with variation in the number and length of grafted PAM chains. The graft copolymers were characterized by viscometry, infrared (IR) spectroscopy, and thermal analysis studies. Flocculation jar tests were carried out in 0.25 wt % kaolin, iron ore, and silica suspensions. Among the series of graft copolymers, the one with fewest but longest PAM chains shows the better performance. The flocculation characteristics of this best performing graft copolymer are compared with various commercially available flocculants in the three suspensions. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1776–1785, 2001
PP/clay nanocomposites: Effect of clay treatment on morphology and dynamic mechanical properties
Authors: Kodgire Pravin , Kalgaonkar Rajendra , Hambir Sangeeta , Bulakh Neelima , Jog J. P.
Published: October 2004

The morphology and properties of polypropylene (PP)/clay nanocomposites are described. The melt intercalation of organophilic clay was carried out with a single‐screw extruder. The effects of two kinds of treatments of clay are discussed. Maleic anhydride (MAH)‐grafted PP was used as a compatibilizer. The expansion of the intergallery distance of the clay was governed by the interaction between the clay treatment and the compatibilizer. In one case, the composites exhibited significantly reduced intensities of diffraction peaks, suggesting partial exfoliation of the clay layers, whereas for the second clay sample, expansion of the gallery height was noted. The mechanical properties of the PP/clay composites showed significant enhancement in their mechanical and thermal properties. About a 35% increase in the tensile modulus and about a 10% increase in the tensile strength were observed. The thermal degradation temperature increased from 270 to about 400°C as a result of the incorporation of clay, and the extent depended on the dispersion of clay in the composite. The most interesting outcome of this study was the changes in morphology for PP/clay composites, which are reported here for the first time. An optical microscopic study revealed that the PP/clay composites could be crystallized at higher temperatures than pure PP and that the morphology was remarkably altered because of the presence of layers of clay. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1786–1792, 2001
Synthesis, characterization, and adsorption properties of chitosan azacrown ethers bearing hydroxyl group
Authors: Yang Zhikuan , Yang Yuan
Published: October 2004

Two new chitosan azacrown ethers bearing hydroxyl groups (CTS‐DH and CTS‐DO) were synthesized by the reaction of 3‐hydroxyl‐1,5‐diaza‐cycloheptane and 3‐hydroxyl‐1,5‐diaza‐cyclooctane with epoxy‐activated chitosan. Their structures were characterized by elemental analysis, infrared spectra analysis, and X‐ray diffraction analysis. The adsorption and selectivity properties of the hydroxyl azacrown ethers chitosan derivatives for Ag+, Cr3+, Cd2+, and Pb2+ were also investigated. The experimental results showed that the two novel chitosan azacrown ethers have good adsorption capacity for Ag+, and also showed that the grafted chitosan azacrown ethers have high selectivity for the adsorption of Ag+ in the presence of Pb2+ and Cd2+. The selectivity coefficients of CTS‐DH and CTS‐DO were K = 21, K = 42, K = 20.5, K = 41, respectively. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1793–1798, 2001
Spontaneous spreading of emulsions on solid surfaces: Morphology and dynamics
Authors: Forester Jonathan E. , Sunkel Jorge M. , Berg John C.
Published: October 2004

The spontaneous spreading of emulsions of water dispersed in silicone oil onto glass surfaces is examined using differential interference contrast (DIC) microscopy. Spreading occurs via a precursor film from which the emulsion droplets are excluded. The radius of the interline of the bulk drop is found to vary as (time)1/10, as is commonly observed for the spontaneous spreading of pure liquids. The spreading rate constant decreases linearly with the volume percent of the dispersed phase, but drops suddenly to zero at approximately 73% dispersed phase. The width and spreading rate of the precursor film also is found to decrease with dispersed phase concentration. A fingering type of instability is evident at the leading edge of the precursor film, yet has little effect on the spreading rate of either the precursor film or the droplet interline. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1817–1825, 2001
Superabsorbent polymeric materials IX: Effect of cationic structure on swelling behavior of crosslinked poly(sodium acrylate‐co‐cationic monomers) in aqueous salt solutions
Authors: Lee Wen‐Fu , Huang Yu‐Lin
Published: October 2004

Two series of xerogels based on sodium acrylate (SA), trimethyl methacrylamidopropyl ammonium iodide (TMMAAI), trimethyl methacryloyloxyethyl ammonium iodide (TMMAI), and N,N′‐methylene‐bis‐acrylamide (NMBA) as a crosslinker were prepared by inverse suspension polymerization. The water absorbency and swelling kinetic behavior for these xerogels in water or various saline solutions were investigated. The results showed that the swelling behaviors of these absorbents are related to their chemical structures, their compositions, and the type of external salt solutions. There would be effective improvement in the water absorbency of these two gel series by copolymerizing SA with a small amount of cationic monomer (TMMAAI or TMMAI). The initial absorption rates in deionized water were found to be faster for TM series gels than for TA series gels. The two series of superabsorbents had a tendency to absorb water in dilute nitrate aqueous solutions in the order: Fe3+, Ni2+, Ca2+, Cu2+, and Na+ for Fe(NO3)3, Ni(NO3)2, Ca(NO3)2, Cu(NO3)2, and NaNO3 aqueous solution, respectively. The absorbency and initial absorption rate for these gels were related to the gel compositions and salt concentrations. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1827–1837, 2001
Electron‐beam irradiation of poly(vinyl chloride)/epoxidized natural rubber blends in presence of trimethylolpropane triacrylate
Authors: Ratnam Chantara Thevy , Nasir M. , Baharin A. , Zaman Khairul
Published: October 2004

Electron‐beam initiated crosslinking of poly(vinyl chloride)/epoxidized natural rubber blends, which contained trimethylolpropane triacrylate (TMPTA), was carried out over a range of irradiation doses (20–200 kGy) and concentrations of TMPTA (1–5 phr). The gel content increased with the irradiation dose and the TMPTA level, although the increase was marginal at higher doses and higher TMPTA levels. Blends containing 3–4 phr TMPTA achieved optimum crosslinking, which in effect caused the maximum tensile strength (TS) at a dose of 70 kGy. A further addition of TMPTA caused a decline in the TS above 40 kGy that was due to embrittlement, which is a consequence of excessive crosslinking and the breakdown of the network structure. The possible formation of a more open network as a result of the breakdown of the network structure was further confirmed by the modulus results. Dynamic mechanical analysis (tan δ curve) and scanning electron microscopy studies on samples irradiated at 0 and 200 kGy were undertaken in order to gain further evidence on the irradiation‐induced crosslinking. The plasticizing effect of TMPTA prior to irradiation and the formation of microgels upon irradiation were also discussed. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1926–1935, 2001
Immobilization of chymotrypsin with interpolymer complexes of P(TM‐co‐AAm)/PAA
Authors: Wang Hongzuo , Liu Shiyong , Wang Ying
Published: October 2004

Chymotrypsin was immobilized with interpolymer complexes formed by the cationic polymer poly(allyltrimethyl ammonium chloride‐co‐acrylamide) [P(TM‐co‐AAm)] and poly(acrylic acid) (PAA). The introduction of a small amount of cationic groups led to a much stronger polymer–polymer interaction between P(TM‐co‐AAm) and PAA. The characteristic pH sensitivity of this kind of complex provided the possibilities of controlling the activity of the immobilized enzyme and separating the immobilized enzyme from the batch by changing the pH of the medium. Compared with the free enzyme, the immobilized chymotrypsin had higher thermal stability, acid–base stability, and stability in use. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2013–2018, 2001
Entrap‐immobilization of invertase on composite gel fiber of cellulose acetate and zirconium alkoxide by sol–gel process
Authors: Nakane Koji , Ogihara Takashi , Ogata Nobuo , Kurokawa Youichi
Published: October 2004

We prepared a composite gel fiber by the gel formation of cellulose acetate and zirconium tetra‐n‐butoxide. Gel fiber is stable in common solvents, phosphate solution, and electrolyte solution. Invertase was entrap‐immobilized on the gel fiber. The immobilization was easily performed under the mild conditions. The apparent Michaelis constant (Km) and maximum reaction velocity (Vmax) were estimated from Eadie–Hofstee plot for immobilized invertase. The Km of immobilized invertase was larger than that of native invertase, while the opposite tendency was observed for the Vmax. The activity for the immobilized invertase became higher with increasing fiber diameter. It indicates that the hydrolysis of sucrose occurs in the neighborhood of the fiber surface. The thermal stability of the immobilized invertase was higher than those of its native counterpart. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2084–2088, 2001
Effect of network morphology on adhesive performance in emulsion blends of acrylic pressure sensitive adhesives
Authors: Tobing Singa , Klein Andrew , Sperling L.H. , Petrasko Bob
Published: October 2004

High‐gel containing latices and gel‐free latex were blended at various weight ratios. The high‐gel containing latices was made of poly(2‐ethyl hexylacrylate‐stat‐acrylic acid) and the gel‐free latex was made of poly(2‐ethyl hexylacrylate‐stat‐acrylic acid‐stat‐isobutoxymethyl acrylamide) using semicontinuous emulsion polymerization. Films were cast at room temperature and dried at 121°C for 10 min. Adhesive performance was evaluated in terms of loop tack, peel, and shear holding power. It was found that interlinking the microgels by the linear polymer due to the isobutoxymethyl acrylamide‐acrylic acid reaction in the film when heated gave synergistic effects in increasing shear. This interlinking could take place only if the molecular weight between crosslinks (Mc) of the microgels was greater than the entanglement molecular weight of the linear polymer (Me), and if the weight average molecular weight of the linear polymer (Mw) was greater than 2 × Me. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2109–2117, 2001
IR spectroscopy study of cyclic anhydride as intermediate for ester crosslinking of cotton cellulose by polycarboxylic acids. V. Comparison of 1,2,4‐butanetricarboxylic acid and 1,2,3‐propanetricarboxylic acid
Authors: Mao Zhiping , Yang Charles Q.
Published: October 2004

In recent years extensive efforts have been made to use multifunctional carboxylic acids as formaldehyde‐free crosslinking agents for cotton to replace the traditional formaldehyde‐based N‐methylol reagents. In our previous research we found that a polycarboxylic acid esterifies cellulose through the formation of a five‐membered cyclic anhydride intermediate by dehydration of two adjacent carboxyl groups. In this research we used Fourier transform IR (FTIR) spectroscopy to study the formation of cyclic anhydride intermediates and crosslinking of cotton by 1,2,4‐butanetricarboxylic acid (BTA) and 1,2,3‐propanetricarboxylic acid (PCA). BTA and PCA form five‐membered cyclic anhydrides in the same temperature range. Both acids form the anhydrides at lower temperatures when a catalyst is present. When an acid molecule is bonded to cotton through an ester linkage, only PCA is able to form a second anhydride intermediate. We found that PCA is a more effective crosslinking agent, and it imparts higher levels of wrinkle resistance to the cotton fabric than BTA. Therefore, the formation of a five‐membered cyclic anhydride by a polycarboxylic acid accelerates the esterification of cotton by the acid. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2142–2150, 2001
Blends of aliphatic polyesters. IV. Morphology, swelling behavior, and surface and bulk properties of blends from hydrophobic poly(L‐lactide) and hydrophilic poly(vinyl alcohol)
Authors: Tsuji Hideto , Muramatsu Hiroki
Published: October 2004

Blend films were prepared from hydrophobic poly(L‐lactide) (PLLA) and hydrophilic poly(vinyl alcohol) (PVA) with different PLLA contents [XPLLA (w/w) = PLLA/(PVA + PLLA)] by solution casting and melt quenching. Their morphology, swelling behavior, and surface and bulk properties were investigated. Polarizing optical microscopy, scanning electron microscopy, differential scanning calorimetry, X‐ray diffractometry, and tensile testing revealed that PLLA and PVA were phase separated in these blend films and the PLLA‐rich and PVA‐rich phases both formed a continuous domain in the blend film of XPLLA = 0.5. The water absorption of the blend films was higher for the blend films of low XPLLA values when compared at the same immersion time, and it was larger than expected from those of nonblended PLLA and PVA films. The dynamic contact angles of the blend films were linearly increased with an increase in XPLLA. The tensile strength and Young's modulus of the dry blend films decreased with a rise in XPLLA, but this dependence was reversed because of the large decreases in tensile strength and Young's modulus for the blend films having high XPLLA values after immersion in water. The elongation at break was higher for the wet blend film than for the dry blend film when compared at the same XPLLA and that of the dry and wet blend films decreased with an increase in XPLLA. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2151–2160, 2001
Synthesis of poly(2‐oxo‐1,3‐dioxolane‐4‐yl) methyl methacrylate by polymer reaction of carbon dioxide and miscibility of its blends with copolymers of methyl methacrylate and ethyl acrylate
Authors: Park Sung‐Young , Lee Hwa‐Soo , Ha Chang‐Sik , Park Dae‐Won
Published: October 2004

Polymeric epoxides were converted to corresponding five‐membered cyclic carbonates in an effective manner. Poly(glycidyl methacrylate) (PGMA) was converted to a poly(2‐oxo‐1,3‐dioxolane‐4‐yl) methyl methacrylate (PDOMMA) by the polymer reaction with carbon dioxide using tetraoctylammonium chloride (TOAC) as a catalyst. The miscibility of blends of PGMA or PDOMMA with copolymers of MMA and ethyl acrylate (MMA‐EA) of two different EA compositions (2 and 5 wt %) was investigated by differential scanning calorimetry (DSC). The films of PGMA or PDOMMA and MMA‐EA (2 and 5 wt %) blends were cast from N,N‐dimethylformamide solution. An optical clarity test and DSC analysis showed that PDOMMA blends were miscible over the entire composition range, but PGMA was immiscible with the MMA‐EA copolymers. It was also found that the miscibility of PDOMMA with 2 wt % MMA‐EA copolymer was better than that of DOMMA with 5 wt % MMA‐EA copolymer. The different miscibility behaviors were investigated in terms of Fourier transform IR spectra and interaction parameters based on the binary interaction model. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2161–2169, 2001
Synthesis and characterization of chlorinated paraffin wax‐bound paraphenylenediamine antioxidant and its application in natural rubber
Authors: Sulekha P. B. , Joseph R. , Prathapan S.
Published: October 2004

p‐Phenylenediamine was chemically attached to low molecular weight chlorinated paraffin wax. The polymer‐bound p‐phenylenediamine was characterized by vapor‐phase osmometry (VPO), proton magnetic resonance spectroscopy (1H‐NMR), infrared spectroscopy (IR), and thermogravimetric analysis (TGA). The efficiency and permanence of the polymer‐bound p‐phenylenediamine as an antioxidant was compared with a conventional amine‐type antioxidant in natural rubber vulcanizates. The vulcanizates showed improved aging resistance in comparison to vulcanizates containing a conventional antioxidant. The presence of liquid polymer‐bound p‐phenylenediamine also reduces the amount of the plasticizer required for compounding. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2183–2189, 2001
Swelling behavior of protein‐based superabsorbent hydrogels treated with ethanol
Authors: Rathna G. V. N. , Damodaran Srinivasan
Published: October 2004

A fish protein‐based superabsorbent hydrogel has been synthesized by modifying 80% of the ϵ‐amino groups of the protein with ethylenediaminetetraacetic dianhydride followed by crosslinking the remaining ϵ‐amino groups with glutaraldehyde. The hydrogel thus prepared was capable of absorbing about 200 g water per g dry gel after centrifuging at 214g. Denaturation of the gel by treatment with absolute ethanol increased the equilibrium water uptake of the gel from 200 to 425 g water per g of dry gel. The saline uptake of the gel also increased from 24 g saline (0.1M NaCl) for the control gel to 35 g saline per g dry gel for the ethanol‐treated gel. Analysis of the structural state of protein chains in the crosslinked swollen gel network using circular dichroism spectroscopy showed that, whereas the protein chains in the control gel were predominantly in β‐turn form, those in the ethanol‐treated sample were mainly in the α‐helical form. In addition to improving the swelling properties, the ethanol treatment offered the following advantages: 1. It dehydrated the gel and thereby eliminated the need for drying the gel. 2. It extracted low molecular weight off‐odor compounds from the protein gel. 3. It could also extract any residual unreacted glutaraldehyde (believed to be carcinogenic) that might be present in the gel. The ethanol used in the process can be easily recovered and recycled in the process. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2190–2196, 2001
Study on a series of main‐chain liquid–crystalline ionomers containing sulfonate groups
Authors: Zhi Junge , Zhang Baoyan , Wu Yanying , Feng Zhiliu
Published: October 2004

A series of main‐chain liquid–crystalline ionomers containing sulfonate groups pendant on the polymer backbone were synthesized by an interfacial condensation reaction of 4,4′‐dihydroxy‐α,α′‐dimethyl benzalazine, a mesogenic monomer, with brilliant yellow (BY), a sulfonate‐containing monomer, and a 1/9 mixture of terephthaloyl and sebacoyl dichloride. The structures of the polymers were characterized by IR and UV spectroscopies. DSC and thermogravimetric analysis were used to measure the thermal properties of those polymers, and the mesogenic properties were characterized by a polarized optical microscope, DSC, and wide‐angle X‐ray diffraction. The ionomers were thermally stable to about 310 °C. They were thermotropic liquid–crystalline polymers (LCPs) with high mesomorphic‐phase transition temperatures and exhibited broad nematic mesogenic regions of 160–170 °C, and they were lyotropic LCPs with willowy leaf‐shaped textures in sulfuric acid. However, the thermotropic liquid–crystalline properties were somewhat weakened because the concentration of BY was more than 8%. The inherent viscosity in N‐methyl‐2‐pyrrolidone suggested that intramolecular associations of sulfonate groups occurred at low concentration, and intermolecular associations predominated at higher concentration. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2210–2218, 2001
A copper‐based reverse ATRP process for the living radical polymerization of methyl methacrylate
Authors: Qin Dong‐Qi , Qin Shu‐Hui , Qiu Kun‐Yuan
Published: October 2004

The reverse atom transfer radical polymerization (RATRP) technique using CuCl2/bipyridine (bipy) complex as a catalyst was applied to the living radical polymerization of methyl methacrylate (MMA). A hexa‐substituted ethane thermal iniferter, diethyl 2,3‐dicyano‐2,3‐diphenylsuccinate (DCDPS), was used as the initiator in this copper‐based reverse ATRP initiation system. The reversible dissociation nature of DCDPS gives a more suitable amount of primary radical than formerly used conventional initiators, such as AIBN. High molecular weight and narrow molecular weight distribution (Mw/Mn ≈ 1.20) of the resulting PMMA was obtained in bulk and in solution polymerization at 85°C. End‐group analysis result by 1H‐NMR spectroscopy shows that the polymer obtained is ω‐functionalized by a chlorine group, which can be used as macroinitiator for chain extension and block copolymerization with a conventional ATRP catalyst. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2237–2245, 2001
Synthesis and characterization of poly(1,4‐dihydroxyanthraquinone terephthalate)
Authors: Meng Qinghua , Huang Deyin , Xiang Liang , Wei Shaohua
Published: October 2004

A novel polymeric dye containing an anthraquinone ring was prepared by solution polycondensation. The molecule geometry was fully optimized on the basis of the AM1 method. The hydrogen bond was formed and retained coplanarity in the molecular structure. In its UV spectrum, a large hypsochromic shift and a hypochromic effect were observed due to polyesterification. The polymeric dye was also characterized by means of IR and TG. Its thermal degradation mechanism was elucidated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2246–2248, 2001
Processing of gel‐spun poly(β‐hydroxybutyrate) fibers
Authors: Gordeyev S. A. , Nekrasov Yu. P. , Shilton S. J.
Published: October 2004

Poly(β‐hydroxybutyrate) (PHB) is a bacteria storage biodegradable polyester that is considered to be a natural substitute for synthetic thermoplastics in many applications. However, brittleness hampers its utility. This study shows that oriented elastic fibers of PHB with favorable mechanical properties (360‐MPa tensile strength and 5.6‐GPa Young's modulus) can be produced by the spinning and drawing of a concentrated PHB gel using a three‐stage fiber processing technique. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2260–2264, 2001
Mechanism analysis of the PEG‐participated Gilch synthesis for soluble poly(p‐phenylene vinylene) derivatives
Authors: Yin Chun , Yang Chang‐Zheng
Published: October 2004

By introducing poly(ethylene glycol) (PEG) into the Gilch reaction system for the synthesis of soluble poly(p‐phenylene vinylene)s (PPVs), significant changes were observed. First, with the involvement of PEG, the polymerization degree increases significantly and the molecular weight distribution becomes wider. The multimodial characteristic of the GPC curves at low conversions is quite evident. Second, at low PEG content, gelation dramatically disappears; with an increase of PEG, gelation reappears. From the above experimental results, the existence of various types of polymerization‐active species and the anionic polymerization mechanism are confirmed, which are due to the dissociation of the carbanion–cation pairs by the complexing effect of PEG. At the same time, the enhanced dissociation of the base (t‐BuO−K+) ion pairs by PEG may be responsible for the dramatic disappearance of gelation. Free t‐BuO− anions have strengthened the basicity and accelerated the conjugation‐formation process which competes with the interchain by‐reactions. Gelation is therefore avoided. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 263–268, 2001
Control of molecular weight in tetrahydrofuran polymerization initiated by heteropolyacid
Authors: Chen Yu , Zhang Guangli , Zhang Hongzhi
Published: October 2004

Both anhydrous and hydrated heteropolyacid can be used to initiate the tetrahydrofuran polymerization in the presence of ethylene oxide promoter, in regard to the crystallization water of the hydrated one as a part of the extra‐added water for controlling the molecular weight. The polyether glycol having number‐average molecular weight of 2000 ± 100 or 1000 ± 50 was prepared in yield beyond 50% by the process without neutralization or neutralization and washing with water after polymerization, respectively. A modified equation based upon conversion of polymerization and concentrations of molecular weight controller and heteropolyacid with a correction factor for predicting the number‐average molecular weight of the product was given. The products were characterized by nuclear magnetic resonance, gel permeation chromatography, and differential scanning calorimetry analyses. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 269–275, 2001
Physical and chemical effects of diethyl N,N′‐diethanolaminomethylphosphate on flame retardancy of rigid polyurethane foam
Authors: Wang Xiu‐Li , Yang Ke‐Ke , Wang Yu‐Zhong
Published: October 2004

Diethyl N,N‐diethanolaminomethylphosphate could react with isocyanate because it contained hydroxy group. This was confirmed by FTIR spectrum. It did not produce any effect on the foam structure of rigid polyurethane foam (RPUF). SEM, IR spectrum, and thermal analysis were used for investigation of the physical and chemical changes during the combustion of flame‐retardant RPUF. It was shown that the flame retardancy changed the thermal decomposition behavior of RPUF, widened the decomposition temperature region of RPUF, reduced the amounts of decomposition products at high temperatures, and increased the decomposition residuals arisen from charring of flame‐retardant RPUF. Those changes improved the flame retardancy of RPUF. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 276–282, 2001
Ethoxylated nonyl phenols and ethoxylated fatty alcohols–ceric ion redox systems for aqueous polymerization of vinyl monomers
Authors: Öz Nesri̇n , Akar Ahmet , Yilmaz Nurten
Published: October 2004

Ethoxylated nonyl phenols, ethoxylated fatty alcohols, and ceric ammonium nitrate redox systems were used for the polymerization of vinyl and acrylic monomers such as acrylonitrile, styrene, and acrylic acid. The initiating radical was formed on reducing organic compound which in turn initiated polymerization to give polymers containing chain ends of ethoxylated nonyl phenols and ethoxylated fatty alcohols that showed much higher water absorption. The effects of the concentration of Ce+4 salt, ethoxylated nonyl phenols, and monomers on both the yield and the molecular weight of corresponding polymers were studied. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 310–313, 2001
Characterization of retanned chrome bovine leather by thermomechanical analysis
Authors: Bosch T. , Manich A. M. , Carilla J. , Palop R. , Cot J.
Published: October 2004

The thermomechanical analysis is applied to characterize the shrinking process of bovine chrome leather. The interpretation of the curves obtained is performed and a value of glass transition temperature is estimated. The influence of the sampling zone on the thermomechanical parameters is discussed. The influence of different “retanning agents,” which act as crosslinking compounds on the fibrous structure of collagen, is also evaluated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 314–322, 2001
Flame‐retarding materials. II. Synthesis and flame‐retarding properties of phosphorus‐on‐pendent and phosphorus‐on‐skeleton polyols and the corresponding polyurethanes
Authors: Wang Tzong‐Liu , Cho Yu‐Liang , Kuo Ping‐Lin
Published: October 2004

A phosphorus‐on‐skeleton compound was synthesized by reacting phenyl dichlorophosphate (PDCP) with 2‐hydroxyethyl methacrylate (HEMA). This monomer was then copolymerized with other acrylic monomers to form a hydroxy‐containing copolymer, which was then used as the polyol in the synthesis of a polyurethane. Phosphorus‐on‐pendent copolymers and phosphorus‐free copolymers and their corresponding polyurethanes were also prepared for comparison with the phosphorus‐on‐skeleton material in terms of their flame‐retardant properties. The flame retardancy and degradation mechanism of these copolymers and polyurethanes were analyzed with thermogravimetric analysis (TGA) and infrared spectroscopy. Although those phosphorus‐on‐skeleton copolymer polyols have less flame‐retarding ability than that of the phosphorus‐on‐pendent copolymer polyol because of less phosphorus content, it was evident that the phosphorus‐on‐skeleton polyurethanes were more effective flame retardants than the phosphorus‐on‐pendent polyurethanes. This was attributed to the fact that the crosslinking arising from the phosphorus‐on‐skeleton copolymer polyols has a tremendous effect on the flame‐retarding ability of the corresponding polyurethanes. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 343–357, 2001
Effect of oxirane groups on curing behavior and thermal stability of vinyl ester resins
Authors: Malik Mona , Choudhary V. , I. K. Varma
Published: October 2004

The effects of oxirane groups in vinyl ester (VE) resin and reactive diluent on curing characteristics and thermal behavior of cured resins are described. Stoichiometric (0.5:1, sample A) as well as nonstoichiometric (0.5:0.85, sample B) ratios of the diglycidyl ether of bisphenol‐A (DGEBA) and methacrylic acid (MA) were used for the synthesis of VE resins. Resin sample B had more residual epoxy groups because of the stoichiometric imbalance of the reactants. VE resins thus obtained were diluted with methyl methacrylate (MMA; 1:1, w/w), and controlled quantities of epoxy groups were introduced by partial replacement of MMA with glycidyl methacrylate (GMA), keeping the overall ratio of resin and reactive diluent constant. Increase of GMA content in resin A or B resulted in a decrease in gel time, indicating that the curing reaction is facilitated by the presence of epoxy groups. An increase in initiator content also reduced the gel time. In the differential scanning calorimetry (DSC) scans, a sharp curing exotherm was observed in the temperature range 107 ± 3–150 ± 1 °C. The onset temperature (Tonset) and peak exotherm temperature (Texo) decreased with increase in GMA content. Heat of curing (ΔH) also increased with increase in GMA content. A broad exotherm was observed after the initial sharp exotherm that was attributed to the etherification reaction. Cured VE resins were stable up to 250–260 °C, and started losing weight above this temperature. Rapid decomposition was observed in the temperature range 400–500 °C. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 416–423, 2001
A new metal chelate sorbent for glucose oxidase: Cu(II)‐ and Co(II)‐chelated poly(N‐vinylimidazole) gels
Authors: Salih Bekir , Pekel Nursel , Güven Olgun
Published: October 2004

Poly(N‐vinylimidazole) (PVIm) gels were prepared by irradiating a binary mixture of N‐vinylimidazole (VIm)–water in a 60Co‐γ source having 4.5 kGy/h dose rate. In the glucose oxidase (GOx) adsorption studies, affinity gels with a swelling ratio of 1100% for PVIm and 40 and 55% for Cu(II)‐ and Co(II)‐chelated PVIm gels, respectively, at pH 6.5 in phosphate buffer were used. FTIR spectra were taken for PVIm and Cu(II)‐ and Co(II)‐chelated PVIm, and glucose oxidase adsorption on these gels, to characterize the nature of the interactions in each species. The results show that PVIm–glucose oxidase interaction is mainly electrostatic and metal ion–chelated PVIm gel–glucose oxidase interaction is of coordinate covalent nature. Cu(II) and Co(II) ions were chelated within the gels via amine groups on the imidazole ring of the gel. Different amounts of Cu(II) and Co(II) ions [maximum 3.64 mmol/g dry gel for Cu(II) and 1.72 mmol/g dry gel for Co(II)] were loaded on the gels by changing the initial concentration of Cu(II) and Co(II) ions at pH 7.0. GOx adsorption on these gels from aqueous solutions containing different amounts of GOx at different pH was investigated in batch reactors. GOx adsorption capacity was further increased when Cu(II) and Co(II) ions were attached [up to 0.53 g GOx/g dry Co(II)‐chelated PVIm gels]. More than 90% of the adsorbed GOx was desorbed in 5 h in desorption medium containing 1.0M KSCN at pH 7.0 for plain gel and 0.05M EDTA at pH 4.9 for metal‐chelated gel. Nonspecific glucose oxidase adsorption on/in the metal ion–chelated PVIm gel was investigated using 0.02M of phosphate buffer solution. The nonspecific GOx adsorption was determined to be about 18% for PVIm and 8% for the metal ion–chelated PVIm gels. The ionic strength effect was investigated both on PVIm and on the metal ion–chelated PVIm gels for the glucose oxidase adsorption. It was found that ionic strength was more effective on the PVIm gel because of the electrostatic interaction between protonated gel and the deprotonated glucose oxidase side chain. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 446–453, 2001
Characterization of branched polymers by SEC coupled with a multiangle light scattering detector. II. Data processing and interpretation
Authors: Podzimek S. , Vlcek T.
Published: October 2004

This study deals with the characterization of branched polymers by means of size‐exclusion chromatography coupled with a multiangle light scattering detector (SEC‐MALS). The application of SEC‐MALS is demonstrated on several randomly branched polystyrene and star‐branched poly(benzyl methacrylate) samples. Various methods of the data processing are compared. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 454–460, 2001
Master curves and lifetime prediction for the epoxy system badge n = 0/m‐XDA by thermogravimetric analysis
Authors: Fraga F. , Rodríguez Núñez E.
Published: October 2004

Master plots were used to corroborate Rn‐type mechanisms calculated in a previous study, using the method proposed by Criado et al. (Thermochim Acta 1989, 147, 377). Analysis of experimental data seems to belong to the family of decelerated curves (Rn) in the range of conversion studied. The lifetime of the system diglycidil ether of bisphenol A (BADGE n = 0)/m‐xylylenediamine (m‐XDA) for different decelerated mechanisms was calculated using thermogravimetric analysis. From the experimental data it was found that the optimum temperature range of use for this material is 60–100°C for all Rn‐type mechanisms, at which corresponding lifetimes range between 190 years and 1 year. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 461–466, 2001
Solution and interfacial behavior of hydrophobically modified water‐soluble block copolymers of acrylamide and N‐phenethylacrylamide
Authors: Abu‐Sharkh B. F. , Yahaya G. O. , Ali S. A. , Kazi I. W.
Published: October 2004

Hydrophobically modified water‐soluble block copolymers were prepared by aqueous micellar copolymerization of acrylamide and small amounts (2 and 3 mol %) of a hydrophobe (N‐phenethylacrylamide) that is characterized by a long spacer that places the aromatic ring far away from the backbone, with the objective of investigating the copolymers' rheological behavior and surface and interfacial activities under various conditions such as polymer concentration, shear rate, temperature, and salinity. As expected, the block copolymers exhibit improved thickening properties attributed to intermolecular hydrophobic associations as the solution viscosity of the copolymers increases sharply with increasing polymer concentration. Additional evidence for intermolecular association is provided by the effect of NaCl, the presence of which substantially enhances the viscosity. An almost shear rate–independent viscosity (Newtonian plateau) is also exhibited at high shear rate and a typical non‐Newtonian shear thinning behavior appears at low shear rates and high temperatures. Furthermore, the block copolymers exhibit high air–liquid surface and liquid–liquid interfacial activities as the surface and interfacial tensions decrease with increasing polymer concentration, indicating strong adsorption of the copolymer at the interface. The surface and interfacial tensions exhibited by the copolymers were found to be relatively insensitive to the concentration of salt (NaCl). © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 467–476, 2001
Preparation and identification of a soluble copolymer from pyrrole and o‐toluidine
Authors: Li Xin‐Gui , Wang Lin‐Xia , Jin Yi , Zhu Zhi‐Liang , Yang Yu‐Liang
Published: October 2004

A series of copolymers were prepared by chemically oxidative polymerization of pyrrole (PY) and ortho‐toluidine (OT) in HCl aqueous medium. The yield, intrinsic viscosity, and solubility of the copolymers were studied by changing the monomer molar ratio. The resulting PY/OT copolymers were identified by FTIR, 1H–NMR, DSC, and WAXD techniques. The experimental results showed that the oxidative polymerization of pyrrole and o‐toluidine is exothermic and the resulting polymers exhibit an enhanced solubility in most organic solvents compared with that of pyrrole homopolymer. The polymer obtained is a real and amorphous copolymer containing pyrrole and o‐toluidine units. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 510–518, 2001
Compounding of poly(dimethyl siloxane) to reduce tack in natural rubber
Authors: Pattanakul Wipawee , Magaraphan Rathanawan , Grady Brian P.
Published: October 2004

Tack in natural rubber latex was reduced by compounding poly(dimethyl siloxane) (PDMS) emulsion in concentrated latex. Sheet and dipped film surfaces were examined with Fourier transform infrared spectroscopy using attenuated total reflection (FTIR–ATR) and by contact angle measurements. Autohesive tack and tensile properties were also determined. For both sheet and dipped film, FTIR–ATR showed that the PDMS concentration was higher at the glass surface than at the air surface. The contact angle of ethylene glycol on the rubber decreased with increasing PDMS content. Autohesive tack for sheet and dipped film also decreased with increasing PDMS amount; however, annealing for 1 week at 70°C in air did cause tack to rise in the sheets. The rubber surface could be made nonadhesive by addition of sufficient PDMS. PDMS caused a decrease in tensile strength for the sheet, especially after annealing; however, PDMS did not cause a substantial decrease in percentage elongation for the sheets, except at relatively high PDMS contents. The tensile strength and percentage elongation for dipped film was not affected by PDMS over the much more limited PDMS concentration range studied. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 519–526, 2001