bluuebunny/crossref_metadata_2025 huggingface dataset:
Chemical modification of Bombyx mori silk with epoxide EPSIB
Authors: Cai Zaisheng , Jiang Guochuan , Qiu Yiping
Published: January 2004

Bombyx mori silk fabrics were chemically modified by EPSIB (a multifunctional silicone‐containing epoxy crosslinking agent). The reactivity of the epoxy groups with silk fibroin was studied by using amino acid analysis. The physical properties of the modified silks such as resiliency (both wet and dry), moisture regain, dyeing behaviors, and solubility in a mixture solvent (C2H5OH × CaCl2 : H2O = 2 : 1 : 8, molar ratio) were examined. The modified silk fabrics exhibited a significantly improved resiliency, a small increase in moisture regain and whiteness, and a slightly decreased tensile strength. The contents of Serine, Trosine, Lysine, and Histidine decreased linearly as the wet crease recovery angle (CRA) increased. The solubility in the mixture solvent also decreased as the wet CRA increased. The changes of physical properties, especially the wet CRA, were mainly due to the presence of stable cross‐links between silk fibroin and epoxy groups. The DSC and TGA analyses showed that EPSIB‐modified silk fibroin had a higher thermal stability compared with the control. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3579–3586, 2004
Effect of blending sodium polyethylene‐5‐sulfoisophthalate on adhesion of clinical bacteria on polyethylene terephthalate
Authors: Hu S.‐G. , Jou C.‐S. , Yang M.‐C.
Published: January 2004

This work studies the adhesion of clinical infecting bacteria, S. aureus and E. coli, on prosthetic polymeric materials. Membranes were prepared from polyethylene terephthalate (PET) blending at various ratios with sodium polyethylene‐5‐sulfoisophthalate (SPES). The membranes were characterized by measuring the contact angle, equilibrium water content, and the surface concentration of sodium sulfonate. The results show that sulfonate makes the membrane more hydrophilic. The surface properties of bacteria were determined by measuring the adhesion to n‐octane (B%) and the contact angles to water and α‐bromonaphthalene. For the four bacteria studied, encapsulated S. aureus was the most hydrophobic and had the highest amount of bacteria attached to the surface of SPES/PET membrane. Furthermore, the attached amount decreased with the increase of the content of SPES. Empirical correlations for predicting the attached amount from the surface properties of both polymer and bacteria were obtained from linear regression. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3587–3594, 2004
Miscibility and crystallization kinetics of poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate)/ poly(methyl methacrylate) blends
Authors: Chiu Hsiu‐Jung
Published: January 2004

The miscibility and crystallization kinetics of the blends of random poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) [P(HB‐co‐HV)] copolymer and poly(methyl methacrylate) (PMMA) were investigated by differential scanning calorimetry (DSC) and polarized optical microscopy (POM). It was found that P(HB‐co‐HV)/PMMA blends were miscible in the melt. Thus the single glass‐transition temperature (Tg) of the blends within the whole composition range suggests that P(HB‐co‐HV) and PMMA were totally miscible for the miscible blends. The equilibrium melting point (T°m) of P(HB‐co‐HV) in the P(HB‐co‐HV)/PMMA blends decreased with increasing PMMA. The T°m depression supports the miscibility of the blends. With respect to the results of crystallization kinetics, it was found that both the spherulitic growth rate and the overall crystallization rate decreased with the addition of PMMA. The kinetics retardation was attributed to the decrease in P(HB‐co‐HV) molecular mobility and dilution of P(HB‐co‐HV) concentration resulting from the addition of PMMA, which has a higher Tg. According to secondary nucleation theory, the kinetics of spherulitic crystallization of P(HB‐co‐HV) in the blends was analyzed in the studied temperature range. The crystallizations of P(HB‐co‐HV) in P(HB‐co‐HV)/PMMA blends were assigned to n = 4, regime III growth process. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3595–3603, 2004
Homopolymer and copolymers of 4‐benzyloxycarbonylphenyl acrylate with glycidyl methacrylate: Synthesis, characterization, reactivity ratios, and application as adhesive for leather
Authors: Selvamalar C. S. Jone , Vijayanand P. S. , Penlidis A. , Nanjundan S.
Published: January 2004

4‐Benzyloxycarbonylphenyl acrylate (BCPA) was prepared by reacting benzyl‐4‐hydroxy benzoate dissolved in methyl ethyl ketone with acryloyl chloride in the presence of triethylamine. The homopolymer and copolymers of BCPA with glycidyl methacrylate (GMA) having different compositions were synthesized in methyl ethyl ketone using benzoyl peroxide as a free‐radical initiator at 70 ± 1°C. All the polymers were characterized by FTIR, 1H‐NMR, and 13C‐NMR spectroscopic techniques. The solubility of the polymers was tested in various polar and nonpolar solvents. The molecular weights (Mw and Mn) and polydispersity indices of the polymers were determined using gel permeation chromatography. The glass‐transition temperatures of the copolymers increased with increasing GMA content in the copolymer. Thermogravimetric analysis of the polymers performed in air showed that the thermal stability of the copolymer increased with increasing BCPA content. Copolymer compositions were determined using 1H‐NMR analysis. The monomer reactivity ratios were determined by the application of conventional linearization methods such as Fineman–Ross (r1 = 0.5237; r2 = 1.9646), Kelen–Tüdös (r1 = 0.4996; r2 = 1.8741), and extended Kelen–Tüdös (r1 = 0.4652; r2 = 1.9046) as well as a nonlinear error‐in‐variables model (EVM) method, using the computer program RREVM (r1 = 0.4644; r2 = 1.8324). The peel strength of the leather adhesives prepared from the copolymers was also determined. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3604–3612, 2004
Crystallization and melt behavior of magnesium hydroxide/polypropylene composites modified by functionalized polypropylene
Authors: Lin Zhidan , Qiu Yixin , Mai Kanchen
Published: January 2004

The crystallization and melting behavior of Mg(OH)2/polypropylene (PP) composites modified by the addition of functionalized polypropylene (FPP) or acrylic acid (AA) and the formation of in situ FPP were investigated by DSC. The results indicated that addition of FPP increased crystallization temperatures of PP attributed to the nucleation effect of FPP. The formation of in situ FPP resulted in a reduced crystallization rate, melting point, and degree of crystallization because of the decreased regularity of the PP chain. For the Mg(OH)2/PP composites, addition of Mg(OH)2 increased the crystallization temperatures of PP attributed to a heterogeneous nucleation effect of Mg(OH)2. Addition of FPP into Mg(OH)2/PP composites further enhanced the crystallization temperatures of PP. It is suggested that there is an activation of FPP to the heterogeneous nucleation effect of Mg(OH)2 surface. The addition of AA also increased the crystallization temperatures of PP in Mg(OH)2/PP composites, but crystallization temperatures of PP were not influenced by the AA content, a phenomenon explained by the heterogeneous nucleation effect of the Mg(OH)2 surface activated by FPP and AA. A synergistic effect on crystallization of PP in Mg(OH)2/PP composites further increased the crystallization temperatures of PP. However, the crystallization temperatures of Mg(OH)2/PP composites modified by in situ FPP were lower than those of Mg(OH)2/PP composites modified by the addition of FPP or AA. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91:3899–3908, 2004
Electrical sensitivity behavior of a hydrogel composed of polymethacrylic acid/poly(vinyl alcohol)
Authors: Kim Seon Jeong , Yoon Seoung Gil , Lee Sang Min , Lee Sang Hoon , Kim Sun I.
Published: January 2004

An interpenetrating polymer network (IPN) composed of polymethacrylic acid (PMAA) and poly(vinyl alcohol) (PVA) was prepared and exhibited electrical sensitivity behavior. The swelling behavior of the PMAA/PVA IPN hydrogel was studied by immersion of the gel in aqueous NaCl solutions at various concentrations and pH values. The stimuli response of the PMAA/PVA IPN hydrogel in electric fields was also investigated. When swollen IPN hydrogel was placed between a pair of electrodes, the PMAA/PVA IPN hydrogel exhibited bending behavior upon the application of an electric field. The PMAA/PVA IPN hydrogel also showed stepwise bending behavior depending on the electric stimulus. Also, for biomedical applications, the bending behavior of PMAA/PVA IPN hydrogel in Hank's solution at pH 7.4 was studied. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91:3613–3617, 2004
Effect of diblock copolymers on morphology and mechanical properties for syndiotactic polystyrene/ethylene‐propylene copolymer blends
Authors: Choi Won Mook , Park O Ok , Lim Jae‐Gon
Published: January 2004

Interfacial agents are often used to compatibilize immiscible polymer blends. They are known to reduce the interfacial tension, homogenize the morphology, and improve adhesion between phases. In this study, two diblock copolymers of styrene/ethylene‐propylene (SEP), which have different molecular weights, were used to compatibilize a blend of syndiotactic polystyrene (sPS) 75% and ethylene‐propylene rubber (EPR) 25% so as to extend the applications of sPS as incoming thermoplastics. The morphological analysis and emulsification curve, which relates the average size of the dispersion particles to the concentration of diblock copolymers added, was used to investigate the efficiency of the interfacial agents on the blend morphology. A notched izod impact test and a tensile test were also performed to determine the compatibilization effect of different molecular weight copolymers on the mechanical properties of the blends and to establish links between morphology and mechanical properties. Results suggest that the lower molecular weight diblock copolymer showed an effective emulsifying capacity for sPS/ERP immiscible blend in morphology and mechanical properties. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91:3618–3626, 2004
Kinetics of thermal degradation of thermotropic poly(p‐oxybenzoate‐co‐ethylene‐2,6‐naphthalate) by single heating rate methods
Authors: Zhang Li , Ma Jinghong , Zhu Xinyuan , Liang Borun
Published: January 2004

The kinetics of thermal degradation of thermotropic liquid crystalline poly(p‐oxybenzoate‐co‐ethylene‐2,6‐naphthalate) (PHB/PEN) with the monomer ratio of 60 : 40 and PEN in nitrogen was studied by dynamic thermogravimetry (TG). The kinetic parameters, including the activation energy Ea, the reaction order n, and the frequency factor ln(Z) of the degradation reaction for PHB/PEN (60 : 40) and PEN were analyzed by the single heating rate methods of Friedman and Chang. The effects of the heating rate and the calculating method on the thermostable and degradation kinetic parameters are systematically discussed. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91:3915–3920, 2004
NMR study of the early stages of gel formation in the PEG/poly(AMPS‐co‐NIPA) semi‐interpenetrating network system
Authors: Zhang Chi , Easteal Allan J.
Published: January 2004

The rate of conversion of the monomers and crosslinker in the formation of a novel semi‐interpenetrating poly(ethylene glycol)/ poly(2‐acrylamido‐2‐methylpropane sulfonic acid‐co‐N‐isopropylacrylamide) copolymer hydrogel was determined by using 1H‐NMR spectrometry. It was established that poly(ethylene glycol) does not participate in the polymerization reactions and that crosslinking by methylenebisacrylamide occurs predominantly in the early stages of copolymer chain growth. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3635–3641, 2004
Development of discrete nanopores I: Tension of polypropylene/ polyethylene copolymer blends
Authors: Lee Jonghwi , Macosko Christopher W. , Bates Frank S.
Published: January 2004

Porous polymeric materials can be prepared by using micromechanical deformations. The development of porous structures in the tension of polyolefin blends are studied with the goal of developing a novel technique to make porous films. It is found in polypropylene/polyethylene copolymer blends of near 50/50 weight ratio that a metallocene polymer pair can produce stable nanopores throughout a wide range of strain, ∼50–700%. Its strain‐to‐break was relatively high, although its continuous phase is a brittle polypropylene. The typical size of nanopores is 10–300 nm; they start to develop at approximately 50% strain. The disruption of craze‐like structures into discrete nanopores seems to be the key mechanism in stabilizing pore development. Varying stretching direction and speed controls the pore morphology. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3642–3650, 2004
Electrical property and stability of electrochemically synthesized polypyrrole films
Authors: Oh Kyung Wha , Park Hyun Jin , Kim Seong Hun
Published: January 2004

Polypyrrole (PPy) films doped with arylsulfonate dopants were prepared by electrochemical polymerization, to investigate the effects of various dopants on conductivities, thermal stabilities, and morphologies of PPy films. Also, HCl was added to those dopants as a cooperating dopant, to improve conductivity of PPy films. Conductivity of PPy film doped with the mixture of each dopant and HCl was improved. Temperature dependency on conductivity for PPy films doped with various dopants was investigated by heating them from 30 to 300°C. For the film doped with TSA, DBSA, and AQSA, conductivity increased up to 150°C and then rapidly decreased, whereas the conductivity of other films decreased after 200°C as temperature increased up to 300°C. Moreover, the film doped with small size dopant such as TSA and HCl/TSA had an interconnected porous fibrillar‐like morphology. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3659–3666, 2004
Synthesis and properties of water soluble polyurethanes based on poly(ethylene glycol)
Authors: Doseva Veneta , Shenkov Stoicho , Vasilev Sasho , Baranovsky Vladimir Y.
Published: January 2004

Water soluble polyurethanes (WSPU)s have been prepared by polycondensation of isophorondiisocyanate and tolylene‐2,4‐diisocyanate with poly(ethylene glycol)s (PEGs) of molecular weights 400, 600, and 1,000. The physicochemical properties of the WSPUs depend on the hydrophilic–hydrophobic balance in their polymeric chain, i.e., the properties are determined by relative density of the hydrophobic diisocyanate residues in WSPU. X‐ray and differential scanning calorimetry studies show that the WSPUs have a degree of crystallinity lower than that of the pure PEGs of the same molecular weights. Like the PEGs the WSPUs prepared form interpolymer complexes with polyacrylic (PAA) and polymethacrylic (PMAA) acids. These complexes are more stable than the (PEG.PAA) and (PEG. PMAA) complexes. The novel compounds can be considered as modified linear PEGs. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3651–3658, 2004
Mechanical strength of durable press finished cotton fabric part V: Poly(vinyl alcohol) as an additive to improve fabric abrasion resistance
Authors: Zhou Wenlong , Yang Charles Q. , Lickfield Gary C.
Published: January 2004

Multifunctional carboxylic acids, such as 1,2,3,4‐butanetetracarboxylic acid (BTCA), are effective crosslinking agents for cotton cellulose and have become the most promising nonformaldehyde durable press (DP) finishing agents to replace the traditional formaldehyde‐based dimethyloldihydroxylethyleneurea (DMDHEU) and its derivatives. DP finishing imparts wrinkle resistance to cotton fabrics and also severely reduces the strength and abrasion resistance of finished fabrics. In this research, we investigated the use of poly(vinyl alcohol) (PVA) as an additive to improve the abrasion resistance of the cotton fabric crosslinked by BTCA. We found that addition of PVA improves the abrasion resistance of the crosslinked cotton fabric when the concentration of PVA exceeds 0.6% in the finish solution. We also found that the use of PVA as an additive has no negative effect on the wrinkle recovery angle (WRA), DP rating, and tensile strength of the treated cotton fabric. This is probably because the molecules of PVA stay on the surfaces of the cotton fibers due to their large molecular sizes. PVA competes with cellulose to esterify BTCA, thus reducing the number of crosslinkages formed on the cotton fiber surface. The reaction of PVA and BTCA may also form a protective layer on the fiber surface, thus reinforcing the mechanically weak points on the fiber surface. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3940–3946, 2004
Study on the cure behavior of 2,7‐dihydroxynaphthalene dicyanate
Authors: Yan Hong‐Qiang , Ji Li , Qi Guo‐Rong
Published: January 2004

The cure behavior of 2,7‐dihydroxynaphthalene dicyanate (DNCY) was studied by means of nonisothermal DSC, isothermal DSC, and FTIR. In nonisothermal DSC, the cure kinetics parameters of DNCY were calculated by the Coats–Redfern method and compared with those of biphenol A dicyanate (BACY). It was revealed that the activation energy of DNCY was enhanced compared with that of BACY because of the presence of naphthalene, and the gelation of DNCY occurred within the conversion range 50–55%, which is lower than that of BACY. In isothermal DSC, a good time–temperature superposition of the conversion profiles of DNCY was obtained during conversions below about 50%. These results were consistent with those obtained by nonisothermal DSC. For the catalyzed system, the autocatalytic behavior prevailed at conversions below 30%, whereas the catalytic behavior occurred only at conversions above 30%.In situFTIR spectra revealed that a triazine network was formed by cyclotrimerization of the OCN functional group during the cure process for systems with and without catalysts. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3927–3939, 2004
Synthesis and properties of new polymerized monomer reactants matrix resins of pyrrolone–benzimidazole copolymers containing pyridine unit
Authors: Yang Hai‐Xia , Li Yan‐Feng , Liu Jin‐Gang , Yang Shi‐Yong , Yin Da‐Xue , Zhou Lincheng , Fan Lin
Published: January 2004

A series of new polymerized monomer reactants (PMR) matrix resins of poly(pyrrolone‐benzimidazole)s containing a pyridine unit (PPBP) were synthesized by polycondensation of monoethyl ester of cis‐5‐norbornene‐endo‐2,3‐dicarboxylic acid, 2,6‐diphenyl ester pyridinedicarboxylic acid or 3,5‐diphenyl ester pyridinedicarboxylic acid, and diethyl ester of 4,4′‐oxydiphthalic acid with 3,3′‐diaminobenzidine in a mixing solution of anhydrous ethyl alcohol and N‐methylpyrrolidone under given temperature and pressure conditions. The resulting resin solutions showed good solubility in polar organic solvents and stability at room temperature. The corresponding PPBP matrix resin, molded powder, and molded plate were prepared by undergoing amidation, imidization, cyclization, and crosslinking reactions when the reaction temperature was increased from 80 to 350°C, successively; the crosslinking structure was formed by the reverse Diels–Alder reaction at 270–290°C under 50 MPa pressure (2.5–3.5 MPa displayed by the pressure meter). The chemical reactions and properties of the resulting PPBP were studied by means of FTIR, TGA, and DMA methods, and the results indicated that the kinds of PPBP materials retain excellent thermal stability and processability; when the initial decomposition temperature was above 620°C the Tg was at 413.5°C for 3,5‐PPBP‐20 molded plate. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3981–3990, 2004
Preparation and optical performance of chiral polymers having azobenzene segments
Authors: Liu Jui‐Hsiang , Yang Po‐Chih
Published: January 2004

A series of monomeric azobenzene derivatives of 6‐(4‐nitro‐4′‐oxy‐azobenzene acrylate with carbon numbers of 6 and 11, and the chiral monomer of bornyl 4‐(6‐acryloyloxyhexyloxy)‐phenyl‐4′‐benzoate were synthesized. Chiral polymers having bornyl group end‐capped pendants with azobenzene‐derived segments were prepared. Molecular structures and polymer compositions were confirmed by using 1H‐NMR, elemental analysis, FTIR, and UV–vis analyzers. Thermodynamic properties of both monomers and polymers were investigated. Specific rotations of chiral monomers and polymers were estimated by using an automatic digital polarimeter. Liquid crystalline textures of monomers and polymers were analyzed by using a polarizing optical microscope and confirmed by a small‐angle X‐ray analyzer. The optical reflection characteristics of composite cells with chiral nematic liquid crystal and various amounts of azobenzene derivatives were evaluated by using a UV–vis spectrophotometer. The reliability and stability of the composite cells with E48/S811 and azobenzene derivatives were studied. The photoisomerization of the chiral polymer film was investigated by using SEM and AFM analyzers. It was found that the UV irradiation of a laser spot caused the shrinkage of polymer film due to the photoisomerization of azobenzene segments. The contraction of the polymer film can be recovered by heat treatment. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3693–3704, 2004
Synthesis and characteristics of interpenetrating polymer network hydrogels composed of alginate and poly(diallydimethylammonium chloride)
Authors: Kim Seon Jeong , Yoon Seoung Gil , Kim Sun I.
Published: January 2004

Temperature‐ and pH‐responsive interpenetrating polymer network (IPN) hydrogels, with sodium alginate (SA) and poly(diallydimethylammonium chloride) (PDADMAC), constructed by a sequential IPN method, were studied. The characterizations of the IPN hydrogels were investigated by FTIR, DSC, and swelling tests under various conditions. The prepared IPN hydrogels exhibited relatively high swelling ratios, in the range of 380–690%, at 25°C. The swelling ratios of SA/PDADMAC IPN hydrogels were pH and temperature dependent. DSC was used for the quantitative determination of the freezing and nonfreezing water contents of the hydrogels. The amount of free water increased with the increasing PDADMAC content of the IPN hydrogels. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3705–3709, 2004
Effects of a new compatibilizer system on the flexural properties of wood–polyethylene composites
Authors: Geng Y. , Li K. , Simonsen J.
Published: January 2004

A novel wood–plastic compatibilizer system containing a paper wet‐strength agent as a wood‐binding domain and stearic anhydride as a polyethylene (PE) binding domain was investigated. Treatment of wood flour with a commercial paper wet‐strength agent Kymene® 557H (simply called Kymene) before the mixing of PE and the wood flour increased the modulus of rupture (MOR) and the modulus of elasticity (MOE) of the resulting wood–PE composites. Addition of stearic acid in the mixing of PE and the wood–Kymene mixture further increased the MOR and MOE. Stearic anhydride was even more effective than stearic acid in the increase of the MOR and MOE. Compared to wood–PE composites without a compatibilizer, the stearic anhydride–Kymene compatibilizer system increased the MOR by about 33% and the MOE by about 40%. The stearic anhydride–Kymene compatibilizer system gave a slightly lower MOR, but higher MOE than those of the commercially used compatibilizer (maleic anhydride‐grafted polypropylene). The compatibilization mechanisms were proposed as follows: Kymene not only bound to wood fibers, but also strengthened and stiffened the wood fibers. Stearic anhydride formed covalent linkages such as ester and amide with the Kymene‐consolidated wood fibers and the long hydrocarbon chain of the stearic anhydride bonded to the PE matrix through entanglements and/or cocrystallization. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3667–3672, 2004
Novel surface modification of high‐density polyethylene films by using enzymatic catalysis
Authors: Zhao Jingchan , Guo Zhian , Ma Xiaoyan , Liang Guozheng , Wang Junlong
Published: January 2004

The surface of high‐density polyethylene (HDPE) films was modified by an enzyme, soybean peroxidase (SBP). The enzymatic surface modification was performed using a peroxidase as catalyst and hydrogen peroxide as oxidizing agent. The chemical composition and morphology of HDPE surfaces were characterized by X‐ray photoelectron spectroscopy, infrared spectroscopy, and scanning electron microscopy. Results showed that after enzymatic treatment, the O/C atomic ratio of HDPE surfaces increased, and new functional groups such as –CO– appeared. Moreover, the surface of treated HDPE films became rougher than untreated surfaces. The hydrophilicity of treated and untreated HDPE films was analyzed by UV–vis spectroscopy and contact angle measurements. The decreased contact angle of the HDPE with water and increased adsorption ability of the surface to a water‐soluble dye clearly indicated that enzymatic treatment can significantly increase the hydrophilicity of the surfaces of HDPE films. The catalytic mechanism of SBP was also discussed. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3673–3678, 2004
Water‐insoluble polymers with ability to remove metal ions
Authors: Rivas Bernabé L. , Villegas Sandra
Published: January 2004

Crosslinked poly[3‐(methacryloylamino)propyl]dimethyl(3‐sulfopropyl)ammonium hydroxide‐co‐2‐acrylamido glycolic acid [P(MAAPDSA‐co‐AGCO)] was synthesized by radical polymerization and tested as an adsorbent under competitive and noncompetitive conditions for Cu(II), Cd(II), Hg(II), Zn(II), Pb(II), and Cr(III) by batch and column equilibrium procedures. The resin–metal ion equilibrium was achieved before 1 h. The resin showed a maximum retention capacity value for Hg(II) at pH 2 of 1.084 meq/g. The recovery of the resin was investigated at 20°C under different concentrations of HNO3 and HClO4. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3679–3685, 2004
Constrained shrinkage of highly oriented poly(methyl methacrylate) fibers
Authors: Wright Debra D. , Lautenschlager Eugene P. , Gilbert Jeremy L.
Published: January 2004

Constrained shrinkage of fibers is the primary method used to examine orientation in amorphous materials. During the test, fibers are constrained, heated, and the stress that develops is measured as a function of time and temperature. This article describes an apparatus developed to measure that stress and a series of experiments for melt‐spun poly(methyl methacrylate) fibers fabricated under three conditions: (1) constant viscosity, (2) increasing temperature, and (3) increasing draw velocity. Results show that both the rates of rise and the decay of the fiber shrinkage stress have an Arrhenius relationship with temperature. Fibers fabricated at a constant viscosity have the same maximum shrinkage stress and rate of stress decay. As the processing temperature decreases or as draw velocity increases, for other parameters held constant, the maximum shrinkage stress increases. The rate of stress rise increases with decreasing processing temperature or increasing draw velocity. Maximum shrinkage stress also increases with increasing molecular orientation when measured by a different test, free heat‐induced shrinkage of the fibers. However, it was not possible to correlate both of these results to rubber elasticity theory attributed to the high degree of orientation present in the fibers and high polydispersity in the starting material. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 4047–4056, 2004
Preparation of membranes by electropolymerization of pyrrole functionalized by a ferrocene group
Authors: Naji A. , Cretin M. , Persin M. , Sarrazin J.
Published: January 2004

The preparation of dense membranes by the electropolymerization of functionalized pyrrole (Py) by ferrocene units was carried out. The synthesis of N‐[3‐(pyrrol‐1‐yl)propyl]ferrocene‐1‐carboxamide (or [(ferrocenyl)amidopropyl] pyrrole, FAPP) is described. The electropolymerization of the monomer on platinum electrode and on stainless‐steel meshes was studied. The electroactivity of the grafted ferrocenyl group of the FAPP monomer was confirmed and the electrochemical properties of the electrogenerated FAPP film were investigated. The stability in potentiostatic and potentiodynamic modes of FAPP films was low and, to improve the latter, the electrochemical preparation of the copolymer between the pyrrole and the FAPP was performed. The electrochemical characterization of the copolymer showed that it was possible to control the oxidation state of both electroactive compounds of the film. The FAPP/Py copolymer was then prepared on stainless‐steel meshes to produce membranes, whose transport properties were electrochemically controllable. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3947–3958, 2004
Effects of EPDM and wollastonite on structure of isotactic polypropylene blends and composites
Authors: Šmit Ivan , Musil Vojko , Švab Iztok
Published: January 2004

Polypropylene blends and composites with 5, 10, and 15 vol % of EPDM and 2, 4, and 6 vol % of untreated and treated wollastonite filler were examined by applying different techniques. Elastomeric ethylene/propylene/diene terpolymer (EPDM) component and wollastonite influenced the crystallization process of isotactic polypropylene (iPP) matrix in different ways. The nucleation of hexagonal β‐iPP, the increase of overall degree of crystallinity, and crystallite size of iPP were more strongly affected by wollastonite than the addition of EPDM was. Both ingredients also differently influenced the orientation of α‐form crystals in iPP matrix. Wollastonite increased the number of a*‐axis‐oriented α‐iPP lamellae plan parallel to the sample surface, whereas the addition of EPDM reoriented the lamellae. The orientation parameters of ternary composites exhibited intermediate values between those for binary systems because of the effects of both components. EPDM elastomer considerably affected well‐developed spherulitization of iPP, increasing the spherulite size. Contrary to EPDM, because of nucleating ability or crystal habit, wollastonite caused significantly smaller iPP spherulites. Small spherulites in ternary iPP/EPDM/wollastonite composites indicated that the wollastonite filler (even in smallest amounts) exclusively determined the morphology of ternary composites. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 4072–4081, 2004
Reactive blends of polyamide 6 with polyester elastomer using coupling agents
Authors: Kim Byung Kyu , Baek Sang Hyun , Kim Min Soo
Published: January 2004

In situ compatibilized melt blends of polyamide 6 (PA‐6) with polyester elastomer (PEL) were prepared in a corotating twin‐screw extruder using two types of coupling agent (CA): diglycidyl ether of bisphenol A (DGEBA) and 1,4‐phenylene bis(2‐oxazoline) (PBO). The notched impact strength of PA‐6 and PA‐6/PEL blends increased with the addition of coupling agent, especially DGEBA, and the maximum impact toughening of the blend was obtained with 0.6 mol % DGEBA, the composition of minimum domain size observed from SEM. Viscosities of the untreated blends increased over those of the base resins at low frequencies. Viscosities of both the base resins and the blends increased with the addition of CA, and the effect was much more pronounced with DGEBA, especially for PA‐6 and PA‐6–rich blends. The crystallization temperature (Tc) of PEL increased over 10°C, whereas the Tc of PA‐6 decreased by 2–3°C in the blends. With the addition of coupling agents, the crystallization melting temperature (Tm) and Tc of PA‐6 decreased by up to 5°C with DGEBA, implying that the crystallization of PA‐6 is disturbed by the in situ formed PA‐6–CA–PEL or PA‐6–CA–PA‐6 type copolymer. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3966–3973, 2004
Polyacrylonitrile‐g‐poly(vinyl alcohol) membranes for the pervaporation separation of dimethyl formamide and water mixtures
Authors: Kurkuri Mahaveer D. , Aminabhavi Tejraj M.
Published: January 2004

Poly(vinyl alcohol) as well as its grafted copolymer membranes with polyacrylonitrile (PAN‐g‐PVA) were prepared and used to separate water and dimethyl formamide mixtures by the pervaporation technique. The three following membranes were prepared: (1) pure PVA; (2) 46% grafted PAN‐g‐PVA; and (3) 93% grafted PAN‐g‐PVA. Pervaporation separation experiments were carried out at 25°C for the feed mixture containing 10 to 90% water. By use of the transport data, permeation flux, separation selectivity, swelling index, and diffusion coefficients have been calculated. By increasing the grafting of the membrane, flux decreased, whereas separation selectivity increased slightly over that of pure PVA membrane. Arrhenius activation parameters for transport processes were calculated for 10 mass % water containing feed mixture by using flux and diffusion data obtained at 25, 35, and 45°C. Transport parameters were discussed in terms of sorption‐diffusion principles. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 4091–4097, 2004
Newsprint paper waste as a fiber reinforcement in rubber composites
Authors: Nashar D. E. El. , Abd‐El‐Messieh S. L. , Basta A. H.
Published: January 2004

The investigation of the economical use of lignocellulose waste, which is one of the environmental problems facing third‐world nations, is ongoing. In this study, we intended to increase the use of newsprint fibers in the rubber industry. For this reason, we treated newsprint fibers with sodium silicate and magnesium chloride, and we examined the water retention values and thermal degradation analyses of the treated fiber waste. The activation energy of degradation was evaluated with the Coats–Redfern method of analysis. The effects of the addition of different amounts [0–60 parts per hundred parts of rubber by weight (phr)] of untreated and treated newsprint fibers on both the electrical and mechanical properties of two different types of rubber (natural rubber and acrylonitrile rubber) were studied. This study led us to the conclusion that the addition of treated newsprint fiber waste at a concentration of 40 phr could lead to an end product characterized by good electrical and mechanical properties. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3410–3420, 2004
Evidence that intrauterine and postnatal androgens affect the development of pyloric stenosis
Authors: James William H.
Published: January 2004

BACKGROUND

It is rather well established that the causal antecedents of pyloric stenosis (PS) contain both genetic and environmental factors. However, in spite of substantial quantities of epidemiological data, no widespread environmental causal agent has yet been established. There have been recent extensions of our knowledge of the endocrine consequences of fetal growth restriction and of the endocrine determinants of sex ratio. It seemed worth reviewing the epidemiological data on PS in the light of these new developments to see whether this would provide a basis for a plausible hypothesis on these suspected environmental causes of PS.

METHODS AND RESULTS

The search terms “pyloric stenosis” and (“epidemiology” or “risk factors”) were combined on the Ovid Medline data base for the years 1966 onwards. The data from the resulting papers were augmented by notes occasioned by almost daily reading at the Library of the Royal Society of Medicine (London) for the past 25 years. (Electronic data retrieval systems do not access incidentally recorded data such as sib sex ratios).

CONCLUSIONS

It is hypothesized that high intrauterine and early postnatal androgen levels constitute an environmental cause of PS. Birth Defects Research (Part A) 67:000–000, 2003. © 2003 Wiley‐Liss, Inc.
Sex ratio and associated risk factors for 50 congenital anomaly types: Clues for causal heterogeneity
Authors: Rittler Monica , López‐Camelo Jorge , Castilla Eduardo E.
Published: January 2004

BACKGROUND

Sex ratio (SR) deviations have been reported for many congenital anomalies, but so far no satisfactory explanation for these deviations has been found. The aim of this study was to detect sex‐related differences in the association between risk factors and congenital anomalies, and to relate these differences with possibly underlying causes of birth defects.

METHODS

Between 1982 and 1999, 1,444,646 newborn infants were examined by the Estudio Colaborativo Latino Americano de Malformaciones Congénitas (ECLAMC) network of South American maternity hospitals. Male relative risks were established for 39,425 infants with 50 selected single anomalies. Associations between male sex and risk factors were identified in nonmalformed infants. In malformed infants, sex‐related risk differences were established, and the SR of these infants, with and without associated risk factors, were compared.

RESULTS

Infants with neural tube defects (NTDs) and intrauterine growth restriction had a lower SR than those with normal growth, while spina bifida without hydrocephaly (SB[sHy]) was the only NTD subtype without a significant female predominance. Multigravidity lowered the SR of SB(sHy) and HPP (HPP) cases. Increased paternal age inverted the SR of cleft lip (CL) with or without cleft palate (CL[P]) cases from male to female.

CONCLUSIONS

The results indicate etiological differences between high and low SB, a stronger relationship between multigravidity and female sex of the offspring than between multigravidity and a specific congenital anomaly, and a possible involvement of dominant mutations for CL(P), as suggested by the association with increased paternal age. Birth Defects Research (Part A) 67:000–000, 2003. © 2003 Wiley‐Liss, Inc.
Mature ovarian cystic teratoma with a highly differentiated homunculus: A case report
Authors: Kuno Naohiko , Kadomatsu Kenji , Nakamura Makoto , Miwa‐Fukuchi Takahiko , Hirabayashi Norio , Ishizuka Takao
Published: January 2004

BACKGROUND

Mature ovarian cystic teratomas, which are commonly observed benign ovarian tumors, consist of ectodermal, mesodermal, and endodermal components that are generally disorganized. In this report, we document a case in which the solid portion of an ovarian teratoma demonstrated considerable differentiation, forming a doll‐like structure.

CASE

A 25‐year‐old virginal Japanese woman underwent surgery for an ovarian tumor that was diagnosed as a mature teratoma. A solid mass within the tumor was found to have a head, trunk, and extremities. Consequently, this mass was diagnosed as a mature fetiform teratoma (homunculus). Brain, eye, spinal nerve, ear, teeth, thyroid gland, bone, bone marrow, gut, trachea, blood vessels, and phallic cavernous tissue were confirmed microscopically. Distinctive features were the clear anterior‐posterior, ventral‐dorsal, and left‐right axes, with a spatially well‐organized arrangement of the organs. An eye was located on the front of the head, a spinal nerve lay dorsal to the spinal bones, the thyroid gland was anterior to the trachea, and the gut was deep inside the trunk.

CONCLUSIONS

These findings indicate that the information necessary for organization of the body plan may be conserved and transmitted, even with parthenogenesis. Mature cystic teratomas of the ovary are mostly benign and do not always attract detailed attention. However, precise analyses of such tumors may significantly enhance our understanding of both parthenogenetic and normal human development. Birth Defects Research (Part A), 2003. © 2003 Wiley‐Liss, Inc.
Immunostimulation by complete Freund's adjuvant, granulocyte macrophage colony‐stimulating factor, or interferon‐γ reduces severity of diabetic embryopathy in ICR mice
Authors: Punareewattana Korawuth , Holladay Steven D.
Published: January 2004

BACKGROUND

Increased risk of fetal malformation is a complication occurring in pregnant women with type 1 diabetes. Local (uterine) immune stimulation has been shown to reduce diabetes‐induced teratogenesis in mice. Limited information is available regarding the ability of diverse methods of maternal immune stimulation to cause this effect or regarding timing requirements of the immune stimulation.

METHODS

Diabetes was induced in pregnant ICR mice by streptozocin (STZ) injection. Three different techniques of maternal immune stimulation, complete Freund's adjuvant (CFA), granulocyte‐macrophage colony‐stimulating factor (GM‐CSF), or interferon‐γ (IFN‐γ), were then used to stimulate the immune system of the mice.

RESULTS

Approximately 50% of fetuses from hyperglycemic (>26 mM/liter blood glucose) dams were malformed, with neural tube defects predominating. Maternal immune stimulation during the time of normoglycemia, i.e., prior to the onset of hyperglycemia, was necessary to reduce teratogenic effects associated with hyperglycemia for each of the immune stimulants. The immune‐stimulated diabetic mice then produced significantly lower and approximately equal numbers of malformed fetuses: CFA 20.9%, GM‐CSF 23.3%, and IFN‐γ 13.9%.

CONCLUSIONS

These results suggest that mechanistically diverse forms of nonspecific immune activation result in protection against diabetes‐related teratogenesis, but only if given prior to onset of hyperglycemia. Birth Defects Research (Part A) 67:000–000, 2003. © 2003 Wiley‐Liss, Inc.
A self‐priming microfluidic diaphragm pump capable of recirculation fabricated by combining soft lithography and traditional machining
Authors: Sin Aaron , Reardon Christopher F. , Shuler Michael L.
Published: January 2004

Fluid transport is crucial in the development of microanalytical devices. While there are many micropump designs available, most are incapable of sustaining recirculation of fluid at μL/min to mL/min levels. We have designed and fabricated a positive displacement micropump by combining soft lithography with traditional bulk machining. The micropump is actuated through pneumatic pressure. The pump is self‐priming and is suitable for recirculating fluid through a microfluidic device containing mammalian cell culture. By custom designing the volume of the pumping chamber, tight control of the output flow rate can be obtained by changing the actuation frequency. It can also be fabricated easily on plastic substrates without access to expensive microfabrication equipment. © 2004 Wiley Periodicals, Inc.
Expression of recombinant vitellogenin in the yeast Pichia pastoris
Authors: Ding J.L. , Lim E.H. , Li H.F. , Kumar J.K. , Lee S.L. , Lam T.J.
Published: January 2004

Vitellogenin (Vtg) plays vital roles as precursor to the yolk proteins and as carrier for lipids, carbohydrates, phosphates, metal ions, vitamins, and hormones into the oocytes during the massive deposition of yolk nutrients for subsequent nourishment of the developing embryos. Reproductive success is highly sensitive to the nutritional quality of the broodstock diet, which greatly affects the egg and larval viability. We present a novel strategy for genetically engineering a Pichia pastoris yeast strain that constitutively produces recombinant Vtg (rVtg), for application as an enriched feed. The tilapia Oreochromis aureus Vtg (OaVtg) cDNA (5.3 kb) was cloned into a nonsecretory pGAPZA vector. Clones containing up to 31 copies of glyceraldehyde‐3‐phosphate dehydrogenase (GAP)‐promoter‐driven Vtg expression cassettes were isolated. These clones expressed a membrane‐associated intracellular rVtg protein of 194 kDa, constituting up to 1.16% of total protein. To facilitate future purification of rVtg, we explored the possibility of secreting rVtg using the native Vtg secretion signal and the α‐factor secretion signal of Saccharomyces cerevisiae. However, neither signal promoted the secretion of rVtg. The clones maximally expressed rVtg at 23°C, reaching a peak at 22 h in shake flasks and 16 h in a fermentor. The clones exhibited a significant increase in essential amino acids and long‐chain polyunsaturated fatty acids, which are important for its application as a high‐quality nutrient feed. © 2004 Wiley Periodicals, Inc.
Resistance to signal activation governs design features of the MAP kinase signaling module
Authors: Chapman Stephen , Asthagiri Anand R.
Published: January 2004

Given its broad influence over numerous cell functions, redesigning the mitogen‐activated protein (MAP) kinase signaling module would offer a powerful means to engineer cell behavior. Early challenges include identifying quantitative module features most relevant to biological function and developing simple design rules to predictably modify these features. This computational study delineates how features such as signal amplification, input potency, and dynamic range of output may be tuned by manipulating chief module components. Importantly, the model construction identifies a metric of resistance to signal activation that quantitatively predicts module features and design trade‐offs for broad perturbations in kinase and phosphatase expression. Its predictive utility extends to dynamic properties such as signal lifetime, which often dictates MAP kinase effect on cell function. Taken together, we propose that predictably altering MAP kinase signaling by tuning resistance is not only a feasible engineering strategy, but also one exploited by natural systems to allow each MAP kinase to exert pleiotropic effects in a context‐dependent manner. External stimuli not only activate kinases, but also alter phosphatase expression and activity, thereby reconfiguring a single module for quantitatively distinct modes of signaling such as transient vs. sustained dynamics, each with unique effects on cell function. © 2004 Wiley Periodicals, Inc.
Protein disulfide isomerase, but not binding protein, overexpression enhances secretion of a non‐disulfide‐bonded protein in yeast
Authors: Smith Jason D. , Tang Benjamin C. , Robinson Anne Skaja
Published: January 2004

In eukaryotes, secretory proteins are folded and assembled in the endoplasmic reticulum (ER). Many heterologous proteins are retained in the ER due to suboptimal folding conditions. We previously reported that heterologous secretion of Pyrococcus furiosus β‐glucosidase in Saccharomyces cerevisiae resulted in the accumulation of a large fraction of inactive β‐glucosidase in the ER. In this work, we determine the effect of introducing additional genes of ER‐resident yeast proteins, Kar2p (binding protein [BiP]) and protein disulfide isomerase (PDI), on relieving this bottleneck. Single‐copy expression of BiP and PDI worked synergistically to improve secretion by ∽60%. In an effort to optimize BiP and PDI interactions, we created a library of β‐glucosidase expression strains that incorporated four combinations of constitutively or inducibly‐expressed BiP and PDI genes integrated to random gene copynumbers in the yeast chromosome. Approximately 15% of the transformants screened had secretion level improvements higher than that seen with single BiP/PDI gene overexpression, and the highest secreting strain had threefold higher β‐glucosidase levels than the control. Nineteen of the improved strains were re‐examined for β‐glucosidase secretion as well as BiP and PDI levels. Within the improved transformants BiP and PDI levels ranged sevenfold and tenfold over the control, respectively. Interestingly, increasing BiP levels decreased β‐glucosidase secretion, whereas increasing PDI levels increased β‐glucosidase secretion. The action of PDI was unexpected because β‐glucosidase is not a disulfide‐bonded protein. We suggest that PDI may be acting in a chaperone‐like capacity or possibly creating mixed disulfides with the β‐glucosidase's lone cysteine residue during the folding and assembly process. © 2004 Wiley Periodicals, Inc.