bluuebunny/crossref_metadata_2025 huggingface dataset:
Solid polymer electrolytes. VII. Preparation and ionic conductivity of gelled polymer electrolytes based on poly(ethylene glycol) diglycidyl ether cured with α,ω‐diamino poly(propylene oxide)
Authors: Liang Wuu‐Jyh , Chen Ting‐Yen , Kuo Ping‐Lin
Published: February 2004

Crosslinked polymer electrolyte networks were prepared from poly(ethylene glycol) diglycidyl ether blended with an epoxy resin (diglycidyl ether of bisphenol A) in different ratios and then cured with α,ω‐diamino poly(propylene oxide) in the presence of lithium perchlorate (LiClO4) as a lithium salt. The ionic conductivities of these polymer electrolytes were determined by alternating current (AC) impedance spectroscopy. Propylene carbonate (PC) was used as a plasticizer to form gelled polymer electrolyte networks. The conductivities of the polymer electrolytes containing 46 wt % PC plasticizer were approximately 5 × 10−4 S cm−1 at 25°C and approximately 10−3 S cm−1 at 85°C. These polymer electrolytes were homogeneous and exhibited good mechanical properties. The effects of the polymer composition, plasticizer content, salt concentration, and temperature on the ionic conductivities of the polymer electrolytes were examined. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1264–1270, 2004
Microwave‐promoted rapid synthesis of new optically active poly(amide imide)s derived from N,N′‐(pyromellitoyl)‐bis‐L‐isoleucine diacid chloride and aromatic diamines
Authors: Mallakpour Shadpour , Shahmohammadi Mohammad Hassan
Published: February 2004

A pyromellitic dianhydride (benzene‐1,2,4,5‐tetracarboxylic dianhydride) was reacted with L‐isoleucine in acetic acid, and the resulting imide acid [N,N′‐(pyromellitoyl)‐bis‐L‐isoleucine] (4) was obtained in a high yield. 4 was converted into N,N′‐(pyromellitoyl)‐bis‐L‐isoleucine diacid chloride by a reaction with thionyl chloride. The polycondensation reaction of this diacid chloride with several aromatic diamines, including 1,4‐phenylenediamine, 4,4′‐diaminodiphenyl methane, 4,4′‐diaminodiphenylsulfone (4,4′‐sulfonyldianiline), 4,4′‐diaminodiphenylether, 2,4‐diaminotoluene, and 1,3‐phenylenediamine, was developed with two methods. The first method was polymerization under microwave irradiation, and the second method was low‐temperature solution polymerization, with trimethylsilyl chloride used as an activating agent for the diamines. The polymerization reactions proceeded quickly and produced a series of optically active poly(amide imide)s with good yields and moderate inherent viscosities of 0.17–0.25 dL/g. All of the aforementioned polymers were fully characterized by IR, elemental analyses, and specific rotation. Some structural characterization and physical properties of these optically active poly(amide imide)s are reported. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 951–959, 2004
Viscosity‐reducing effects of two semiflexible liquid‐crystalline polyesters with different chain rigidities in a matrix of polycarbonate
Authors: Zhao Wei , Zhao Jianhong , Chen Yu , Wei Xu Jian , Lu Xuehong
Published: February 2004

Two liquid‐crystalline polyesters (LCPs) with different chain rigidities were synthesized and melt‐blended with polycarbonate (PC) at an LCP concentration of 2 wt %. The first LCP (LCP1) was based on hydroxybenzoic acid (HBA), hydroquinone (HQ), sebacic acid (SEA), and suberic acid (SUA) and contained a relatively high concentration of flexible units (SEA and SUA). The other one (LCP2) was based on HBA, hydroxynaphthoic acid, HQ, and SEA and contained a lower concentration of flexible units. LCP2 had a much lower melting point, a higher clearing temperature, and a lower shear viscosity than LCP1. The blending was carried out at 265, 280, and 300°C for both systems. The extent of the viscosity reduction induced by the addition of LCP1 depended on the compounding temperature, and the lowest viscosity was achieved with blending at 280°C. This was attributed to the large interfacial area and interactions between the flexible segments of LCP1 and PC chains at the interface. For PC/LCP2, the viscosity reduction was not significantly dependent on the compounding temperature, and when it was compounded at 280°C, its viscosity was significantly higher than that of PC/LCP1 at high shear rates, even though LCP2 had lower viscosity. A scanning electron microscopy study revealed that, with compounding at 265 and 280°C, LCP2 was poorly dispersed in the PC matrix in comparison with LCP1, and the glass‐transition‐temperature depression caused by the addition of LCP2 was relatively small. This indicated that interfacial interactions in PC/LCP2 were weaker, thereby explaining their different rheological behavior in comparison with PC/LCP1. With compounding at 300°C, the compatibility of both systems improved because of transesterification reactions, but this did not lead to a lower viscosity because of the lack of physical interfacial interactions. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 960–969, 2004
Preparation and characterization of highly oriented poly(γ‐benzylL‐glutamate) networks and gels with long channels with micrometer‐scale diameters
Authors: Yamane Yuji , Kanekiyo Masahito , Koizumi Satoshi , Zhao Chenhua , Kuroki Shigeki , Ando Isao
Published: February 2004

Poly(γ‐benzylL‐glutamate) (PBLG) gels with highly oriented α‐helix chains were prepared by the crosslinking of PBLG chains through changes in the concentration of ethylenediamine, used as a crosslinker, in 1,4‐dioxane in the presence of the strong magnetic field of an NMR magnet with a strength of 10.5 T. The experimental results showed that in one of these gels, long channels with an average diameter of about 100 μm were formed by phase separation between crosslinked PBLG and the solvent. Furthermore, three‐dimensional1H‐NMR imaging patterns showed that the long channels were aligned in the direction parallel to the α‐helix axis. The PBLG gel was swollen in the direction perpendicular to the α‐helix axis, but it was not swollen in the direction parallel to the α‐helix axis. The X‐ray diffraction patterns of the gel showed that the interchain distance between the two nearest neighboring PBLG chains changed from 13.4 to 18.1 Å with a change in the swelling degree. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1053–1060, 2004
Film‐forming process from globular polytetrafluoroethylene latex particles
Authors: Dürrschmidt Th. , Hoffmann H.
Published: February 2004

Film formation from an aqueous polytetrafluoroethylene (p‐TFE) latex dispersion on glass tissues was studied. The p‐TFE particles were of globular shape, had a diameter of 220 ± 20 nm, and were of high crystallinity (∼ 100%). The melting point of the material was 332°C. For the study of the film formation, stripes of glass tissues were dipped in a concentrated p‐TFE latex dispersion and then removed. The samples were then dried in an oven at well‐defined temperatures below and above the melting temperature Tm of the p‐TFE latex. The film formation from the particles was then studied by taking SEM micrographs of the surface of the samples at various times and conditions. It was observed that the globular particles kept their globular shape and did not coalesce to a film as long as the temperature of the sample was kept below Tm. When the samples were tempered with T > Tm the film formation started. The neighboring globular particles coalesced into wormlike particles that grew in length with time. During the growth of the particles the thickness of the particles remained constant. In the first stages the film can be imagined as a porous network from short wormlike objects. It is concluded that the coalescence begins above Tm when the polymer chains become mobile along their axis. The chains of neighboring particles can therefore interdigitate into each other along their main axis and crosslink the particles. The proposed mechanism of film formation is confirmed by AFM micrographs on which the individual particles from the dispersion are still visible in the wormlike objects. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 733–742, 2004
Polymers with palladium nanoparticles as active membrane materials
Authors: Yu J. , Liu R. Y. F. , Poon B. , Nazarenko S. , Koloski T. , Vargo T. , Hiltner A. , Baer E.
Published: February 2004

A new in situ infusion method was used to incorporate small amounts (∼1 wt %) of metal and metal oxide particles into a polymer matrix. Nanosized particles were observed by both transmission electron microscopy and atomic force microscopy. Oxygen (O2) and carbon dioxide (CO2) transport properties of the infused materials were investigated using a dynamic diffusion approach in which both testing and purge gases can be controlled. It was discovered that trace amounts (∼2%) of hydrogen (H2) in the purge gas were sufficient to considerably reduce the O2 flux of FEP films infused with palladium (Pd) nanoparticles, up to a 200‐fold decrease. In contrast, H2 essentially had no effect on the transport of CO2. The generality of the remarkable reduction in oxygen flux was also demonstrated with films of PP, LLDPE, PET, and nylon 6,6 infused with Pd nanoparticles. This oxygen‐scavenging effect became more pronounced at lower oxygen concentrations. The catalytic role of Pd in the reaction of O2 and H2 and the enormous surface area provided by the dispersed nanoparticles were responsible for this highly efficient oxygen‐scavenging effect. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 749–756, 2004
Detection of residual acidic groups in several poly(N‐alkyl methacrylate)s using photophysical and photochemical probes
Authors: Christoff M. , Yamaki S. B. , De Oliveira M. G. , Atvars T. D. Z.
Published: February 2004

This work describes three different methods for detecting acidic groups copolymerized in poly(methyl methacrylate), poly(ethyl methacrylate), and poly(n‐butyl methacrylate) chains using molecular spectroscopy. The first was based on the shift of the tautomeric equilibrium of 4‐dimethylaminoazobenzene by acidic groups that modify the absorption band in the UV/vis spectra. We also show that the acidic groups present in the polymer influenced the anti‐syn photoisomerization reaction of this dye. Further, a mercury–dithizonate complex was completely bleached when sorbed in poly(n‐alkyl methacrylate) matrices containing acidic groups. Finally, Nile Blue A was used as a spectrophotometric probe to quantify the amount of acidic groups in these polymers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 830–838, 2004
Binary blends based on poly(N‐isopropylacrylamide): Miscibility studies with PVA, PVP, and PAA
Authors: Mano Valdir , Ribeiro E Silva Maria Elisa Scarpelli , Barbani Niccoletta , Giusti Paolo
Published: February 2004

Blends of poly(vinyl alcohol) (PVA), poly(acrylic acid), (PAA), and poly(vinyl pyrrolidone) (PVP), with poly(N‐isopropylacrylamide) (PNIPAM), were prepared by casting from aqueous solutions. Mechanical properties of PNIPAM/PVA blends were analyzed by stress–strain tests. Differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) were employed to analyze the miscibility between the polymeric pairs. The results revealed that PNIPAM is not miscible with PVA and PVP in the whole range of composition. On the other hand, PNIPAM interacts strongly with PAA forming interpolymer complex due to the formation of cooperative hydrogen bonds. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 743–748, 2004
Effect of maleic acid content on network structure and swelling properties of poly(N‐isopropylacrylamide‐co‐maleic acid) polyelectrolyte hydrogels
Authors: Çaykara Tuncer
Published: February 2004

Hydrogels were prepared by γ‐ray–induced polymerization in aqueous solution of N‐isopropylacrylamide (NIPA) and of NIPA with three different charge densities, that is, maleic acid (MA) as a comonomer. The swelling behaviors of these hydrogels were analyzed in buffer solutions at various pH and temperature ranges. The equilibrium swelling ratios were relatively high and sensitive to pH and temperature. The polymer–solvent interaction parameter (χ) and the molecular weight between crosslinks (Mc) of P(NIPA/MA) polyelectrolyte hydrogels were calculated from swelling studies in buffer solutions at various pH values and related to MA content. A kinetic study of the absorption determined the transport mechanism as a non‐Fickian type diffusion. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 763–769, 2004
Isothermal crystallization kinetics of polypropylene by differential scanning calorimetry. I. Experimental conditions
Authors: Hernández‐Sánchez Fernando , del Castillo Luis F. , Vera‐Graziano Ricardo
Published: February 2004

Reliable isothermal crystallization kinetic studies can be achieved by differential scanning calorimetric techniques only under restricted conditions. In the case of isotactic polypropylene, our results indicate that those conditions are met in the range of 3°C below the isothermal crystallization temperature Tc. Experimentally, it is only in this range when the complete crystallization peak can be registered by the DSC and depicted in a thermogram. Just around this temperature interval, the Avrami exponent n = 3 for bulk crystallization, whereas for any other test the isothermal temperature Tit, nonisothermal conditions prevail and the Avrami exponent deviates from the expected value. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 970–978, 2004
Kinetic analysis of poly(N‐isopropylacrylamide‐co‐dimethylaminoethyl methacrylate) microgel latex formation
Authors: Zhang Y. , Zha L. S. , Fu S. K.
Published: February 2004

Curves of the conversion and particle size versus the time in the preparation of poly(N‐isopropylacrylamide‐co‐dimethylaminoethyl methacrylate) microgel latices by surfactant‐free emulsion polymerization were measured. The copolymerization reactions were rapid, and their rates increased with the dimethylaminoethyl methacrylate (DMAEMA) concentration in the polymerization recipe. Particle formation occurred by a homogeneous nucleation mechanism, in which DMAEMA helped to colloidally stabilize the primary particles. In addition, a strong dependence of the water‐soluble‐polymer (WSP) formation on the DMAEMA concentration was found, and the DMAEMA content in the WSP was significantly higher than that in the microgel particle. A drastic variation of the crosslinking density within the microgel particle during the polymerization process was found through a comparison of the particle size determined by quasi‐elastic light scattering with that determined by transmission electron microscopy. Finally, on the basis of these results, the mechanism of particle formation in this polymerization process was examined. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 839–846, 2004
Cure study of an acrylic resin to develop natural fiber composites
Authors: Behzad T. , Sain M.
Published: February 2004

In the present study a new environmentally friendly acrylic resin was characterized to develop a high‐performance biocomposite for future work. Differential scanning calorimetry measurements were used to determine onset of curing reaction as well as the degree of cure at a certain temperatures. Swelling equilibrium data for an acrylic resin were generally analyzed using the Flory–Rehner equation for a perfect network, to obtain a measurement of the molar mass between two crosslinks and the crosslink density of polymer, and to establish the effect of temperature and time on these parameters. The crosslink density of cured resin at 180°C and 10 min indicates the completion of a major part of the reaction under those conditions. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 757–762, 2004
Incorporation of carbon dioxide into soybean oil and subsequent preparation and studies of nonisocyanate polyurethane networks
Authors: Tamami B. , Sohn S. , Wilkes G. L.
Published: February 2004

Epoxidized soybean oil was effectively converted to carbonated soybean oil (CSBO) containing five‐membered cyclic carbonates by reaction with carbon dioxide in the presence of tetrabutylammonium bromide as catalyst at 110°C in high yield. CSBO could easily react with di‐ or tri‐ primary amines to give the corresponding nonisocyanate polyurethane networks (NIPUs). A model reaction between CSBO and n‐butylamine showed the effective ring opening of five‐membered cyclic carbonate moieties in the triglyceride molecules by the amine to form β‐hydroxyurethane systems. NIPUs were further characterized by the three techniques of solvent extraction, dynamical mechanical analysis, and limited tensile testing. The data from these methods confirmed the network character of all materials and also showed how the levels of extractables, Tg, and mechanical properties varied with type of amine and, in the case of ethylenediamine, the effect of stoichiometry. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 883–891, 2004
Piezoelectricity of vinylidenefluoride–trifluoroethylene copolymer films in various poling conditions
Authors: Sathanon U. , Fukura S. , Sekiguchi A. , Ogino K. , Miyata S.
Published: February 2004

Piezoelectricity of ferroelectric thin polymer films strongly depends on the poling condition. We can classify them as conventional electrical and novel nonelectrical poling. These experiments show the comparative results on piezoelectricity induced from various poling processes (i.e., electrical corona poling, nonelectrical surface‐energy poling, and a combination of both methods simultaneously in various poling conditions). The most interesting result confirmed that the piezoelectricity increased significantly when the combination poling was applied with appropriate metal substrate and temperature decreasing rate. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 856–860, 2004
Physical characteristics of sweet potato pulp/polycaprolactone blends
Authors: Lee Eun‐Jung , Kweon Dong‐Keon , Koh Bong‐Kyung , Lim Seung‐Taik
Published: February 2004

Sweet potato pulp (SSP) obtained as a by‐product from starch extraction was blended with polycaprolactone (PCL) to prepare a biodegradable plastic material. In the blends, PCL was used as a reinforcing agent. The SPP/PCL blends were prepared by compression‐molding under high temperature and pressure, at different SPP/PCL ratios, and the mechanical properties of the molded specimens were tested. Matrix structure and thermal properties were measured by using a Fourier transform infrared (FTIR) spectrophotometer, scanning electron microscope (SEM), differential scanning calorimetry (DSC), and thermogravimetric analyzer (TGA). Mechanical properties (tensile and flexural properties) were also measured to find the most suitable ratio in a SSP/PCL blend. During compression molding of the SPP/PCL blends under high pressure and temperature, chemical reaction occurred between SPP and PCL, and thus, thermal stability and mechanical strength of the blends increased and water uptake decreased. Also, by increasing the PCL content in the blend, the matrix in the blend became more homogeneous, and consequently, mechanical strength of the molded specimen increased. At 7/3 or 6/4 weight ratio of SSP/PCL, water uptake of the molded specimen became substantially less than that at 8/2. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 861–866, 2004
Study on curing kinetics and curing mechanism of epoxy resin based on diglycidyl ether of bisphenol a and melamine phosphate
Authors: Chen Wen‐Yi , Wang Yez‐Zen , Chang Feng‐Chih
Published: February 2004

The curing kinetics of the diglycidyl ether of bisphenol A/melamine phosphate (DGEBA/MP) was analyzed by the DSC technique. The Kissinger and Flynn–Wall–Ozawa methods were applied to determine the dynamic kinetics of the DGEBA/MP system. The activation energies obtained by these two methods were 83.9 and 85.6 kJ/mol, respectively. An autocatalytic equation was applied to determine the isothermal curing kinetics of the DGEBA/MP system. The DGEBA/MP system exhibits autocatalytic behavior in the isothermal curing procedure, whose kinetics fits well with the autocatalytic mechanism. The obtained isothermal curing activation energy of the DGEBA/MP system was 110.0 kJ/mol. The curing mechanism of DGEBA with melamine phosphate was investigated using FTIR, 13C solid‐state NMR, and 31P solid‐state NMR. It involved an epoxide–amine reaction, etherification of phosphoric acid and epoxy, dehydration, and thermal oxidation of the hydroxyl group of the DGEBA/MP system. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 892–900, 2004
Active control on molecular conformations and tensile properties of spider silk
Authors: Pan Z. J. , Li C. P. , Xu Q.
Published: February 2004

The mechanical properties of spider dragline silk vary with the spinning conditions, and molecular conformation is one of the important factors for the strength and strain of materials. Four kinds of Araneus ventricosus spider dragline silk fibers, measured by Raman microscopic spectrometry, were produced under different conditions: (1) reeled at the rate of 2 cm/s; (2) secreted by a dropping spider from a 100‐cm‐high table; (3) spun by spiders raised in two different containers. The Raman spectra of these fibers showed that the spinning method and growing environment of spiders had evident influences on the molecular conformations and tensile properties of dragline silk, and the dragline silk obtained from a dropping spider contained the greatest number of molecules with highly oriented β‐sheet structures and gave higher stress/strain values. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 901–905, 2004
The tribological behavior of micrometer and nanometer TiO2 particle‐filled poly(phthalazine ether sulfone ketone) composites
Authors: Shao Xin , Liu Weimin , Xue Qunji
Published: February 2004

Micrometer and nanometer TiO2 particle‐filled poly(phthalazine ether sulfone ketone) (PPESK) composites with various filler volume fractions from 0.5 to 7.5 vol % were prepared by heating compression molding. The friction and wear behaviors of the PPESK composites were evaluated using the block‐on‐ring test rig by sliding PPESK‐based composite blocks against a mild carbon steel ring under dry friction conditions. The wear debris and the worn surfaces of the PPESK composites filled with micrometer and nanometer TiO2 particles were investigated by using a scanning electron microscope (SEM), while the structures of PPESK composites and wear debris were analyzed with IR spectra. Experimental results show that antiwear properties of the PPESK composites can be improved greatly by filling nanometer TiO2 particles, and the friction coefficient decreases when the filler volume fraction is below 2.5%, but when the filler volume fraction is above 2.5% the friction coefficient increases gradually with increasing filler volume fraction. In the case of micrometer TiO2 filler, wear rates increase with increasing filler volume fractions under identical test conditions, and the friction coefficients are less sensitive to the filler volume fraction. It was also found that the wear mechanism of micrometer TiO2 particle‐filled PPESK is mainly severe adhesion and abrasive wear, while that of nanometer TiO2 particle‐filled PPESK is mainly slight abrasive wear. In the former case, there are no transfer film formed on the surface of the counterpart steel, and wear debris are in the form of long and large ribbon. While in the latter case, the wear debris was granule and their size was about 10 μm. In case of 1 vol % nanometer TiO2 particle‐filled PPESK composites, the transfer film was fairly thinner and smoother, and the transfer film provided better coverage on the surface of steel ring, while that of 7.5 vol % was thicker and discrete. These account for the different friction and wear behavior of micrometer and nanometer TiO2 particle‐filled PPESK composite. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 906–914, 2004
Experimental and simulation studies on molecular transport of substituted monocyclic aromatic liquids into fluoropolymer sheet membranes: Liquid structure–diffusion, –sorption, and –permeation relationships
Authors: Aminabhavi Tejraj M. , Naidu B. Vijaya Kumar
Published: February 2004

The present study reports an investigation on the molecular transport of 10 monocyclic aromatic liquids (benzene, chlorobenzene, 1,2‐dichlorobenzene, bromobenzene, toluene,p‐xylene, trimethylbenzene, ethylbenzene, methoxybenzene, and ethoxybenzene) at 40 and 50°C through sheet polymeric membranes (FLS‐2650) using a sorption gravimetric technique. Diffusion and permeation coefficients of these liquids were calculated from the sorption data using Fick's diffusion equation. Sorption results were analyzed typically in the case of benzene and chlorobenzene to compute the concentration profiles at different depths along the thickness direction of the sheet membranes and at different time intervals by solving the Fick's equation under appropriate boundary conditions, based on the numerical simulation method developed in “C” language using a finite‐difference method. Transport results were analyzed to establish the relationships between the penetrating liquid structures with diffusion, permeation, and sorption data. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 991–996, 2004
Electrical behavior of chitosan and poly(hydroxyethyl methacrylate) hydrogel in the contact system
Authors: Kim Seon Jeong , Kim Han Il , Shin Su Ryon , Kim Sun I.
Published: February 2004

Semi‐interpenetrating polymer networks (semi‐IPNs), as polymer hydrogels composed of chitosan and poly(hydroxyethyl methacrylate) (PHEMA), exhibiting electrical‐sensitive behavior, were prepared. The swelling behavior of the chitosan/PHEMA hydrogels was studied by immersing the gels in various concentrations of aqueous NaCl solution. The electrical responses of the semi‐IPN hydrogel, in applied electric fields, were also investigated. When the semi‐IPN hydrogels were swollen, where one electrode was placed in contact with the gel and the other fixed 30 mm apart from one, they exhibited bending behavior on the application of an electric field on a contact system. The electroresponsive behavior of the present semi‐IPN was also affected by the electrolyte concentration of the external solution. The semi‐IPN also showed various degrees of increased bending behavior depending on the electric stimulus. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 915–919, 2004
Water‐swelling behavior of hydrophobic porous copolymer resins composed of two kinds of crosslinkers
Authors: Zhao Xin , Wang Xunhua , Yan Jun
Published: February 2004

Hydrophobic, but water‐swellable, porous copolymer resins composed of divinylbenzene (DVB) and ethylene glycol dimethacrylate (EGDM) or ethylene glycol diacrylate (EGDA) were prepared by using purified DVB (98.8%) in the presence of toluene as porogen. The EGDM/DVB resins thus obtained, whose polarity was nearly identical to that of the resins based on DVB and methyl methacrylate (MMA) at the same DVB levels, were water‐swellable by direct contact with water up to a DVB content of 64%, whereas the latter did not swell in water at any DVB levels. EGDA is also hydrophobic, but with a polarity greater than that of EGDM. As a result, the EGDA/DVB resins were more water swellable than EGDM/DVB resins, and could also be prepared as water‐swellable materials by using technical DVB (79.3%), besides the use of the purified DVB. All these results were explained on the basis of the network rigidity (crosslinking density) and the polymer polarity of the resins that were formed in the presence of a well‐solvating porogenic solvent. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 997–1004, 2004
Permselectivity of polyamide composite membrane modified by solvent
Authors: Cai Bang‐Xiao
Published: February 2004

Asymmetric reverse osmosis (RO) polyamide (PA) composite membrane may be modified by means of a solvent‐processing technique into pervaporation (PV) membrane for separating organic aqueous solution. Formic acid, acetic acid, phosphoric acid, hydrochloric acid, phenol, and so forth, better solvents for PA, were selected as the modifying agents in this study. The effect of the modifying conditions (type and concentration of the modifying agent, processing time of membrane in liquid medium) on the sorption of modified membranes was investigated. After the PA composite membrane was treated with 8 wt % acetic acid for 1 h, the swelling rate for water (Sw) increased, whereas that for isopropanol (SIPA) decreased, compared with that of the nonmodified membrane. The difference between Sw and SIPA of the membrane treated with acetic acid was greater than that with other modifying agents. The separation factor and flux of the modified membrane were correspondingly maximal when it was used in a PV separating isopropanol aqueous solution. The contact of solvent molecules in liquid medium with polymer chains in the PA membrane and the intranodular chains in the PA membrane tending to diffuse by reptation toward the solvent molecules were the principal causes leading to a change of structure of asymmetric PA composite membrane. The mechanism of changing membrane structure by means of the solvent‐processing technique may better interpret the modification of PA composite RO membrane. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1005–1010, 2004
Effect of process variables on bulk development of air‐textured poly(trimethylene terephthalate) bulk continuous filaments
Authors: Chuah Hoe H.
Published: February 2004

Bulk development of air‐textured poly(trimethylene terephthalate) (PTT) bulk continuous filaments was studied by varying two texturing parameters, yarn preheating and texturing hot air temperatures. The yarns were subsequently heat treated from 80 to 160°C. Bulk was found to go through a maximum with increasing heat‐treatment temperature because of two competing mechanisms. Upon heat treatment, the fiber shrunk and developed bulk; heat treatment also simultaneously induced structural reorganization through annealing and stabilized the fiber against shrinkage. When the later mechanism became dominant, bulk development decreased with further increase of heat‐treatment temperature. The temperature at which the maximum occurred increased when the yarn preheating or texturing air temperatures were increased. Depending on the extent of annealing and structural reorganization during yarn preheating and during texturing, fibers with equivalent bulk measured at a single temperature did not behave the same way over a range of heat‐treatment temperatures. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1011–1017, 2004
A novel dendritic acrylate oligomer: Synthesis and UV curable properties
Authors: Xu Dong‐Mei , Zhang Ke‐Da , Zhu Xiu‐Lin
Published: February 2004

An dendritic acrylate oligomer with eight double bonds (DAO) was synthesized by Michael addition reaction of ethylene diamine (EDA) and trimethylolpropane triacrylate (TMPTA) under mild conditions, and was easily separated from the reaction system with methanol. The structure of DAO was characterized by IR, 1H‐NMR, and elemental analysis. DAO is UV curable oligomer with low viscosity and high curing speed. Its viscosity was 10.85% of that of the linear acrylic oligomers with similar molecule weight (EBECRYL Resin 285). With Darocure 1173 as the photoinitiator, the curing speed of DAO was respectively 7.5 and 10.3 times higher than that of EBECRYL Resin 605 and EBECRYL Resin 285. Furthermore, the effect of the photoinitiator and active diluent on curing speed of DAO UV curing system was studied. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1018–1022, 2004
Cure characteristics and mechanical properties of short nylon fiber‐reinforced nitrile rubber composites
Authors: Rajesh C. , Unnikrishnan G. , Purushothaman E. , Thomas Sabu
Published: February 2004

Acrylonitrile butadiene rubber (NBR)‐based composites were prepared by incorporating short nylon fibers of different lengths and concentration into the matrix using a two‐roll mixing mill according to a base formulation. The curing characteristics of the samples were studied. The influence of fiber length, loading, and rubber crosslinking systems on the properties of the composites was analyzed. Surface morphology of the composites has been studied using Scanning Electron Microscopy (SEM). Addition of nylon fiber to NBR offers good reinforcement, and causes improvement in mechanical properties. A fiber length of 6 mm was found to be optimum for the best balance of properties. It has been found that at higher fiber loadings, composites show brittle‐type behavior. Composites vulcanized by the dicumyl peroxide (DCP) system were found to have better mechanical properties than that by the sulfur system. The swelling behavior of the composites in N,N‐dimethyl formamide has been analyzed for the swelling coefficient values. Composites vulcanized in the DCP system were found to have higher rubber volume fraction than that in the sulfur system, which indicates better rubber–fiber interaction in the former. The crosslink densities of various composites were also compared. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1023–1030, 2004
Effect of the nature and degree of crosslinking on the catalase‐like activity of polystyrene‐supported schiff base‐metal complexes
Authors: Kumar G. S. Vinod , Mathew Beena
Published: February 2004

Catalase‐like activity of the metal complexes of various crosslinked polystyrene‐supported Schiff bases were carried out and correlated with the nature and degree of crosslinking in the polymer support. Polystyrenes with 2–20 mol % ethyleneglycol dimethacrylate (EGDMA), 1,4‐butanediol dimethacrylate (BDDMA) and 1,6‐hexanediol diacrylate (HDODA) were used as polymer supports. functions of diethylenetriamine and salicylaldehyde were incorporated to the chloromethylpolystyrene by polymer analogous reactions and complexed with Fe(II), Fe(III), Co(II), Ni(II), and Cu(II) ions. The metal uptake decreased in the order: Cu(II) > Co(II) > Ni(II) > Fe(III) > Fe(II), and extent of metal uptake by the various crosslinked system varied with the nature and degree of the crosslinking agent. The polymeric ligands and the metal complexes were characterized by various analytical techniques. The catalytic activities of these metal complexes were investigated towards the decomposition reaction of hydrogen peroxide. Generally among the various metal complexes, the catalytic activities decreased in the order: Co(II) > Cu(II) > Ni(II) > Fe(III) ≅ Fe(II). With increasing rigidity of the crosslinking agent their catalytic activity also decreased. Of the various crosslinked systems, the catalytic activity decreased in the order: HDODA‐ > BDDMA‐ > EGDMA‐crosslinked system. Also, the catalytic activity is higher for low crosslinked systems and decreased further with increasing degree of crosslinking. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1271–1278, 2004
Effect of rare earth elements surface treatment on tensile properties of aramid fiber‐reinforced epoxy composites
Authors: Cheng Xian‐Hua , Wu Ju , Xie Chao‐Ying
Published: February 2004

Solutions of rare earth modifier (RES) and epoxy chloropropane (ECP) grafting modification method were used for the surface treatment of aramid fiber. Tensile properties of both the aramid/epoxy composites and single fibers were tested. The effects of RES concentration on tensile properties of aramid/epoxy composites were investigated in detail to explore an optimum amount of rare earth elements in solution for modifying aramid fiber. The fracture surface morphologies of tensile specimens were observed and analyzed with the aid of SEM. The experimental results show that rare earth treatment is superior to ECP grafting treatment in promoting interfacial adhesion between the aramid fiber and epoxy matrix. Meanwhile, the tensile strengths of single fibers were almost not affected by RES treatment. The optimum performance is obtained when the content of rare earth elements is 0.5 wt %. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1037–1041, 2004
Synthesis and characterization of novel hydrophobically modified polybetaines as pour point depressants
Authors: Didukh Alexander G. , Koizhaiganova Raushan B. , Bimendina Larisa A. , Kudaibergenov Sarkyt E.
Published: February 2004

A novel hydrophobic monomer was synthesized from the acetoacetic ester and dodecylamine by condensation reaction in mild conditions. The modification by the dodecyl groups monomer was involved in the Michael addition reaction with acrylic (or methacrylic) acid followed by radical polymerization. Both linear and crosslinked novel betaine‐type polyampholytes bearing hydrophobic “tail” and hydrophilic “head” were obtained. The linear polymer was characterized by viscometry, FTIR, and Raman spectroscopy. Swelling–shrinking behavior of linear and crosslinked samples was studied in water–DMF and water–DMSO mixtures. The applicability of hydrophobically modified polybetaines as pour point depressants (fluidity improvers) was also demonstrated. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1042–1048, 2004
Effects of high‐energy electron beam on low‐density polyethylene materials containing EVA
Authors: Salehi S. M. A. , Mirjalili G. , Amrollahi J.
Published: February 2004

A series of low‐density polyethylene (LDPE) blends with different amounts of ethylene–vinyl–acetate (EVA) was prepared and irradiated with 10 MeV electron beam in the range of 0–250 kGy at room temperature in air. EVA was used as a compatibilizer and softener in four different amounts: 5, 10, 20, and 30 wt %, based on polyethylene (PE). The crosslinking of the samples was studied on the basis of gel‐content measurements as well as some thermal and mechanical properties of the specimens. The results indicated that the LDPE and LDPE–EVA blends could be crosslinked by a high‐energy electron beam, of which their thermal and mechanical properties changed effectively, however, because of EVA content of the polymer; the blends were more sensitive to lower doses of radiation. These studies were carried out to obtain a suitable compound for heat‐shrinkable tubes. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1049–1052, 2004
Rheological investigation on the interaction of a fluorocarbon and hydrocarbon comodified PAA with a nonionic surfactant in the presence of salt
Authors: Zhuang Dongqing , Hogen‐Esch Thieo E. , Zhang Yunxiang
Published: February 2004

Derivatives of poly(acrylic acid) hydrophobically modified with hydrocarbon group (PH) and both hydrocarbon and fluorocarbon groups (PHF) were synthesized and the association of these copolymers with nonionic surfactant Np7.5 in 0.1M NaCl aqueous solutions was investigated. Microdomains formed in the system of PHF/Np7.5 consist of both hydrocarbon (HC) and fluorocarbon (FC) groups, which is similar to Winnik's mixed model (Kujawa, P. C.; Goh, C. E.; Calvet, D.; Winnik, F. M. Macromolecules 2001, 34, 6387). The hybrid structure of FC and HC groups on the polysoap backbone was proposed to interpret why the miscibility between FC and HC groups was improved. The effect of salt and Np7.5 on PHF and PH solutions was carried out and compared. When the concentration of Np7.5 reaches 0.1 wt % in 0.3 wt % polymer solution especially, physical network junctions become greatly stabilized. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1279–1285, 2004
Modified polypropylene wood flour composites. II. Fracture, deformation, and mechanical properties
Authors: Hristov V. N. , Krumova M. , Vasileva St. , Michler G. H.
Published: February 2004

The effect of grafting level of maleic anhydride (MA) in the maleated polypropylene (PPMA) on the fracture, deformation mechanisms, and mechanical properties of polypropylene (PP) wood flour composites was studied. Tensile strength, elongation at break, and impact strength are noticeably improved with addition of interfacial modifiers as maximum values of the examined mechanical properties were detected when concentration of MA in the compatibilizer was 1 wt %. To explore the microstructure and deformation mechanisms, scanning electron microscopy was employed. It was found that low concentrations of MA up to 1 wt % led to the creation of a thin and irregular polymer layer assisted formation of fibrillated plastic deformation zone around the wood particles, while the bulk PP matrix experienced voiding and brittle fracture. Higher concentrations of MA fetch to stronger interaction between PP and wood flour, the reason for brittle fracture and reduced ductility of the matrix. The impact fracture behavior of the composites during Instrumented impact tests is also discussed with respect to the interfacial bond strength. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1286–1292, 2004
Polyethylene catalytic hydrocracking by PtHZSM‐5, PtHY, and PtHMCM‐41
Authors: Hesse Nathan D. , White Robert L.
Published: February 2004

The mechanisms involved in polyethylene catalytic hydrocracking are investigated by monitoring temperature‐dependent evolution profiles derived from mass spectra obtained while polymer/catalyst samples were heated at a constant rate. Repetitive injection gas chromatography/mass spectrometry (GC/MS) results are used to identify class‐specific fragment ions that represent paraffins, olefins, and alkyl aromatics. Class‐specific ion signals are used to generate isoconversion‐effective activation energy plots from which mechanistic comparisons are made. Studies using PtHZSM‐5, PtHY, and PtHMCM‐41 bifunctional solid acid catalysts in helium and hydrogen are reported. The effects of hydrogen on polyethylene cracking are dramatic and result in significant changes to isoconversion‐effective activation energies. Catalytic cracking mechanisms for the three catalysts are compared and differences are explained by a combination of pore size and acidity effects. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1293–1301, 2004
Bulk conductive polymers prepared from nylon‐6/6,9 copolymer/CuCl2 compounds
Authors: Jia W. , Tchoudakov R. , Narkis M. , Siegmann A.
Published: February 2004

Semiconductive polymers were obtained by soaking nylon‐6/6,9 particles in concentrated CuCl2·2H2O aqueous solutions, followed by reduction of the treated particles with sodium borohydride aqueous solutions. The reduced nylon‐6/6,9/CuCl2 particles were compression molded at a relatively low temperature (160°C). The bulk volume resistivity obtained is at an intermediate level, ∼105 ohm‐cm. The compounds generated by reduction of the nylon‐6/6,9/CuCl2 particles were determined to consist of metallic copper by means of energy‐dispersive X‐ray microanalysis. The metallic copper is responsible for the electrical conductivity of the bulk samples. Samples stored at the ambient atmosphere gradually absorb oxygen and moisture, resulting in a decrease in the conductivity. The morphology of nylon‐6/6,9/CuCl2 samples before and after reduction was studied by a scanning electron microscope and transmission electron microscope. A two‐level hierarchy structure, submicrometer and nano‐sized, of copper particles was observed, forming the conducting copper networks. Molded samples of reduced nylon‐6/CuCl2 and nylon‐6,6/CuCl2 particles, prepared by the same procedure as that of nylon‐6/6,9/CuCl2 particles, were insulating, whereas a reduced nylon‐6/CuCl2 film was moderately conductive. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1367–1373, 2004
Photopolymerization of acrylates in the presence of phenolic derivatives: Role of the photoinitiating system
Authors: Dossot M. , Obeid H. , Allonas X. , Jacques P. , Fouassier J.P. , Merlin A.
Published: February 2004

The effects of wood phenolic compounds on the photopolymerization of an acrylate resin were evaluated under model conditions, in the presence of different photoinitiating systems, based on a bisacylphosphineoxide derivative, an amine, and isopropylthioxanthone. The steady‐state photolysis of these systems and their excited‐state processes were also characterized. The kinetic scheme, derived from these experiments, promoted discussion of the performances attained in photopolymerization experiments. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1154–1164, 2004
Synthesis and properties of fluoroalkyl end‐capped sulfobetaine polymers
Authors: Sawada Hideo , Umedo Michinori , Kawase Tokuzo , Baba Masanori , Tomita Toshio
Published: February 2004

A variety of fluoroalkyl end‐capped 3‐[N‐(3‐acrylamido)propyl‐N,N‐dimethylammonio]propanesulfonate polymers [RF–(APDAPS)n–RF] were prepared by the reactions of fluoroalkanoyl peroxides with the corresponding monomer under very mild conditions. Similarly, fluoroalkyl end‐capped 2‐vinylpyridinio propane sulfonate polymer was obtained by the use of fluoroalkanoyl peroxide. These fluoroalkyl end‐capped sulfobetaine polymers exhibited a good solubility in water; however, these polymers have a poor solubility in other solvents. In particular, RF–(APDAPS)n–RF polymers caused gelation in methanol, although RF–(VPPA)n–RF polymer showed no gelation in methanol. RF–(APDAPS)n–RF polymers were found to form the self‐assembled molecular aggregates with the aggregations of the end‐capped fluoroalkyl segments and the ionic interactions between sulfobetaine segments in aqueous solutions. On the other hand, it was suggested that RF–2‐vinylpyridinio propane sulfonate (VPPS)n–RF polymer is not likely to form the self‐assemblies in aqueous solutions because of the steric hindrance of pyridiniopropyl betaine units in polymer. We also studied the surfactant properties of RF–(APDAPS)n–RF and RF–(VPPS)n–RF polymers compared with those of other fluoroalkyl end‐capped betaine‐type polymers such as 2‐acrylamido‐2‐methylpropanesulfonic acid polymers and 2‐(3‐acrylamidopropyldimethylammonio) ethanoate polymers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1144–1153, 2004
An investigation of cadmium(II) and nickel(II) adsorption by chitin graft copolymer
Authors: Filho José A. R. , Bach Erna E. , Vargas Reinaldo R. , Soares Demétrio A. W. , de Queiroz Alvaro A. A.
Published: February 2004

Chitin hydrogels of poly(vinylpyrrolidone) (VP) were prepared by means of the hydrogen peroxide graft copolymerization process. The effect of the VP grafted chain on water diffusion through the biopolymer was studied. Fourier transform infrared spectra of the VP‐g‐Ch showed an increase in the intensities of the hydroxyl and carbonyl stretching bands indicating a reduction in the hydrogen bonding of chitin. An investigation was undertaken regarding the adsorption of nickel(II) and cadmium(II) ions from aqueous solutions by the VP grafted chitin and the effects of the grafting degree on the Cd2+ and Ni2+ sorption were studied. The Cd2+ and Ni2+ adsorption equilibrium data correlate well with the Freündlich equation. The results indicate that the Ch‐g‐VP graft copolymer under investigation is a potentially powerful chelating material that can be employed for Ni2+ and Cd2+ ion removal from wastewater effluents. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1310–1318, 2004
Effect of bis(diisopropyl)thiophosphoryl disulfide on the covulcanization of styrene–butadiene rubber and ethylene–propylene–diene (monomer) blends
Authors: Ghosh Arup Kumar , Das Amit , Basu Dipak Kumar
Published: February 2004

Covulcanization of elastomer blends constituting styrene–butadiene rubber (SBR) and ethylene–propylene–diene (monomer) rubber (EPDM) was successfully performed in the presence of reinforcing fillers like carbon black and silica by using a multifunctional rubber additive, bis(diisopropyl)thiophosphoryl disulfide (DIPDIS). The polarity of EPDM rubber was increased by a two‐stage vulcanization technique, which allowed the formation of rubber‐bound intermediates. In this way the migration of both curatives and reinforcing fillers in the EPDM–SBR blend could be controlled and cure rate mismatch could be minimized. The process significantly improved the physical properties of the blend vulcanizates. The phase morphology, as evident from the SEM micrographs, was indicative of the presence of a much more compact and coherent rubber matrix in the two‐stage vulcanizates. Different accelerator systems were studied to understand better the function and effectiveness of DIPDIS in developing homogeneity in the blends of dissimilar elastomers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1231–1242, 2004