bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of bentonite on the physical properties and drug‐release behavior of poly(AA‐co‐PEGMEA)/bentonite nanocomposite hydrogels for mucoadhesive
Authors: Lee Wen‐Fu , Chen Yung‐Chu
Published: January 2004

A series of nanocomposite hydrogels for mucoadhesive were prepared from acrylic acid, poly(ethylene glycol) methyl ether acrylate, and intercalated bentonite clay by photopolymerization. The microstructures were identified by X‐ray diffraction (XRD). Results showed that the swelling ratio for the present nanocomposite hydrogels decreased with an increase of bentonite, whereas the gel strength and Young's modulus of the present gels increased with an increase of bentonite. However, the adhesive force of the present gels did not decrease with an increase of bentonite. XRD results indicated that the exfoliation of bentonite was achieved in the xerogels and swollen gels. Finally, the drug‐release behaviors for these gels were also assessed. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2934–2941, 2004
Synthesis and properties of water‐soluble sulfonated acetone–formaldehyde resin
Authors: Pei Meishan , Yang Yongqing , Zhang Xiuzhi , Zhang Jin , Li Yingbo
Published: January 2004

Water‐soluble sulfonated acetone–formaldehyde (SAF) resins were synthesized by the reaction among acetone, formaldehyde, and sodium bisulfite. The factors affecting the properties of SAF resins and optimum conditions of preparation were investigated. The SAF resins prepared under proper conditions have good water solubility and high performance as a superplasticizer used in concrete. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3248–3250, 2004
Synthesis of new optically active poly(amide‐imide)s containing EPICLON and L‐phenylalanine in the main chain by microwave irradiation and classical heating
Authors: Mallakpour Shadpour , Reza Zamanlou Mohammad
Published: January 2004

EPICLON [3a,4,5,7a‐Tetrahydro‐7‐methyl‐5‐(tetrahydro‐2,5‐dioxo‐3‐furanyl)‐1,3‐isobenzofurandione] or [5‐(2,5‐dioxotetrahydrofurfuryl)‐3‐methyl‐3‐cyclohexyl‐1,2‐dicarboxylic acid anhydride] (1) was reacted with L‐phenylalanine (2) in acetic acid, and the resulting amic acid was refluxed under a Dean‐Stark system with benzene, which produced diacid (3) in high yield. Compound (3) was converted to the diacid chloride (4) by reaction with oxalyl chloride in dry carbon tetrachloride. The polycondensation reaction of this diacid chloride (4) with several aromatic diamines such as 4,4′‐sulfonyldianiline (5a), 4,4′‐diaminodiphenylmethane (5b), 4,4′‐diaminodiphenylether (5c), 1,4‐phenylenediamine (5d), 1,3‐phenylenediamine (5e), 2,4‐diaminotoluene (5f), and 1,5‐diaminonaphthalene (5g) was developed by using a domestic microwave oven in the presence of a small amount of a polar organic medium such as N‐methylpyrrolidone (NMP). The polymerization reactions were also performed under two different classical heating methods: low temperature solution polycondensation in the presence of trimethylsilyl chloride, and high temperature polymerization. A series of optically active poly(amide‐imide)s with moderate yield and inherent viscosity of 0.14–0.22 dL/g were obtained. All of the above polymers were fully characterized by IR, elemental analyses, and specific rotation. Some structural characterization and physical properties of this optically active poly(amide‐imide)s are reported. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3281–3291, 2004
Selection of quaternary ammonium groups for optimizing properties of water‐soluble, photosensitive phenolic resins and study of their postcuring mechanism
Authors: Xie Hong‐Quan , Gao Yu , Zhan Xue‐Gui , Xie Dong
Published: January 2004

This article deals with the selection of quaternary ammonium groups for synthesis of water‐soluble, photosensitive phenolic resins, containing acrylate and different quaternary ammonium salt groups (AQSPRs), via ring‐opening reactions of epoxy phenolic resin (EPR) with acrylic acid and with different tertiary amine‐protonic acid salts. Conversion of epoxy groups, solubility, photosensitive properties, and thermal decomposition of the different AQSPRs were compared. Modification of AQSPR with methanol solution of KOH to form phenolic resin containing both quaternary ammonium hydroxide groups and acrylate groups (AQHPR) was also studied. Characterization by IR spectrum, DSC, and thermal gravimetric analysis was carried out. The results showed that in the synthesis of AQSPRs containing different quaternary ammonium salt groups, the efficiency of ring‐opening reaction of epoxy phenolic resin with tertiary amine salt in terms of conversion of epoxy groups decreases in the following order: for the tertiary amine, N,N‐dimethyl benzylamine (DMBA) > triethylamine (TEA) > trimethylamine (TMA) > N,N‐dimethyl aniline (DMA) > triethanolamine (TENA) > tri(n‐butylamine) (TBA); for the protonic acid, HCl > HBr > HCOOH > HI > NaHSO3 > Cl3CCOOH > HClO4 > HBF4. All the AQSPRs except that from HClO4 can be dissolved in water, methanol, DMF, or DMSO. The gel content formed during UV exposure decreases in the following order of acids used in forming quaternary ammonium salt groups: HCl > HCOOH > NaHSO3 > Cl3CCOOH; or decreases in the following order of tertiary amines or hydrohalic acids used in forming the quaternary ammonium groups: TMA. > TEA > DBMA; HCl > HBr > HI. During thermal decomposition of EPR with about half epoxy groups of EPR ring‐opened with tertiary amine salt at 160°C for 0.5 h, water‐insoluble product was formed. The insoluble content and the % decrease of epoxy groups or halide ions increase in the following order: TMA < TEA < DMBA; HCl < HBr < HI. The % decrease of epoxy groups for the insoluble residue is nearly equal to the % decrease of halide ions. A crosslinking reaction mechanism occurred in the thermal decomposition was thus proposed. During the modification of AQSPR with KOH, conversion of quaternary ammonium chloride groups can reach above 90%. The decomposition temperature of the quaternary ammonium groups was lowered from 204 to 120°C after modification of AQSPR with KOH. The photosensitive properties of the resin after modification became lower. It is better to react DMBA · HCl with EPR so as to obtain a product with higher conversion of epoxy groups, good water solubility, moderate photosensitivity, lower decomposition temperature, and better postcuring. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2914–2922, 2004
Gas permeation through water‐swollen polysaccharide/poly(vinyl alcohol) membranes
Authors: Kim Min‐Joung , Park You‐In , Youm Kyung‐Ho , Lee Kew‐Ho
Published: January 2004

The effect of Na‐alginate content on the gas permeation properties of water‐swollen membranes prepared by varying Na‐alginate and poly(vinyl alcohol) (PVA) content in membranes was investigated. The influences of water content and crystallinity of the membranes on the gas permeation performance of the water‐swollen membranes were studied. The gas permeation rate and selectivity of Na‐alginate/PVA water‐swollen membranes were compared with those of the dry membranes. The permeation rates of nitrogen and carbon dioxide through water‐swollen membranes were in the range of 0.4–7.6 × 10−7 to 3.7–8.5 × 10−6 cm3 (STP)/cm2 s−1 cmHg−1, which were 10,000 times higher than those of dry‐state membranes. The permeation rates of mixture gases through water‐swollen Na‐alginate/PVA membranes were found to increase exponentially with the increase of Na‐alginate content, whereas carbon dioxide concentration in permeates was decreased linearly. It was found that the gas permeance of the water‐swollen membranes increased with increasing the Na‐alginate content in the membrane. Gas permeation rates of the water‐swollen Na‐alginate/PVA membranes increased with increasing the water content in the membrane and decreasing the crystallinity of the membrane. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3225–3232, 2004
Fractionated crystallization of dispersed PA6 phase of PP/PP‐g‐MAH/PA6 blends
Authors: Shi Dean , Yin Jinghua , Ke Zhuo , Gao Ying , Li R. KY
Published: January 2004

Fractionated crystallization behavior of dispersed PA6 phase in PP/PA6 blends compatibilized with PP‐g‐MAH was investigated by scanning electron microscopy (SEM), differential scanning calorimeter (DSC), polarized light microscopy (PLM), and wide‐angle X‐ray diffraction (WAXD) in this work. The lack of usual active heterogeneities in the dispersed droplet was the key factor for the fractionated crystallization of PA6. The crystals formed with less efficient nuclei might contain more defects in the crystal structures than those crystallized with the usual active nuclei. The lower the crystallization temperature, the lesser the perfection of the crystals and the lower crystallinity would be. The fractionated crystallization of PP droplets encapsulated by PA6 domains was also observed. The effect of existing PP‐g‐MAH‐g‐PA6 copolymer located at the interface on the fractionated crystallization could not be detected in this work. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3742–3755, 2004
Preparation of aqueous dispersible polyurethane: Effect of acetone on the particle size and storage stability of polyurethane emulsion
Authors: Chinwanitcharoen Charoen , Kanoh Shigeyoshi , Yamada Toshiro , Hayashi Shunichi , Sugano Shunji
Published: January 2004

An aqueous dispersible polyurethane was prepared by the reaction of hydroxyl‐terminated poly(ethylene adipate), dimethylol propionic acid, 4,4′‐diphenylmethane diisocyanate, and ethylene glycol. Formation of the dispersion was achieved by phase inversion of an acetone solution of the polyurethane with water, utilizing carboxylate anion groups as the internal emulsifying sites. The amount of acetone added has a large effect on the particle diameter (0.08 to 8.61 μm) and particle size distribution of the polyurethane emulsion. The storage stability was evaluated in terms of particle size distribution breadth. The aqueous emulsion obtained with no use of acetone was sufficiently stable in storage for at least 6 months. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3455–3461, 2004
Tensile and impact properties of carbon filled nylon‐6,6 based resins
Authors: Heiser Jessica A. , King Julia A. , Konell Jeremiah P. , Miskioglu Ibrahim , Sutter Lawrence L.
Published: January 2004

Electrically and thermally conductive resins can be produced by adding conductive fillers to insulating polymers. Mechanical properties such as tensile modulus, ultimate tensile stress, strain at ultimate tensile stress, and notched Izod impact strength are also important and cannot be ignored. This study focused on performing compounding runs, followed by injection molding and evaluation of tensile and impact properties of carbon filled nylon‐6,6 based resins. The three carbon fillers investigated include an electrically conductive carbon black, synthetic graphite particles, and a surface treated polyacrylonitrile (PAN) based carbon fiber. Resins containing varying amounts of these single carbon fillers were produced and tested. In addition, combinations of fillers were investigated by conducting a full 23 factorial design and a complete replicate. The addition of carbon fiber increased the composite tensile modulus, ultimate tensile stress, and impact strength. Also, in many cases, combining two or three different fillers caused a statistically significant effect at a 95% confidence level. When comparing the results of this study with prior work, it appears that increased heteroatoms present on the carbon fiber surface likely improve composite ultimate tensile stress and impact strength. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2881–2893, 2004
Interfacial behavior of epichlorohydrin–ethyleneoxide–allylglycidyl ether/fluorinated carbon black observed from mechanical and dielectrical properties
Authors: Katada A. , Shimura T. , Tominaga Y. , Asai S. , Sumita M.
Published: January 2004

The purpose of this work was to study the effect of carbon black (CB) surface state on the interaction between CB and polymer matrix, as well as the polymer chain mobility. The mobility of polymer chain absorbed on the CB surface was estimated by using a dynamic mechanical analyzer and an impedance analyzer. The interaction parameter (B) and immobilized polymer layer thickness (ΔR) were estimated from the dynamic mechanical analysis. It was observed that values of B and ΔR decreased with increasing fluorine content on the CB surface. On the other hand, from the dielectric measurement, the Maxwell–Wagner–Sillars (MWS) relaxation peak, accompanied by migration of the charge carriers, accumulated at the interface between polymer and CB, observed at temperatures higher than the glass‐transition temperature (Tg) of the polymer matrix. The activation energy (Ea MWS), calculated from the relaxation frequency of MWS relaxation, was decreased with increasing surface fluorine content. Good agreement was found between the B and the ΔR values estimated from the dynamic mechanical analysis and the Ea MWS calculated from the MWS relaxation frequency estimated from dielectric measurement. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2928–2933, 2004
Study of progesterone release mechanisms from a silicone matrix by a new analytical method
Authors: Taghizadeh S. Mojtaba , Mashak Arezou , Jamshidi Ahmad , Imani Mohammad
Published: January 2004

The release behavior of progesterone from a silicone matrix to release media containing 60% (v/v) alcohol and water was investigated and kinetically evaluated. For this purpose, samples containing 5, 10, or 15% (w/w) micronized progesterone were prepared through the mixing of two‐component silicone and the drug in a thermomixer. The discs were cured with compression molding. Then, the release from a controlled surface area was experimentally determined by a high‐performance thin‐layer chromatography technique, a new method for progesterone analysis. With Higuchi's model, the drug‐release behavior of the dispersion systems was determined by a partition‐controlled process (the relationship between the accumulated amount of the drug released and the time) and a matrix‐controlled process (the relationship between the accumulated amount of the drug released and the square root of time). The release profile determined by experimental data was in good agreement with Higuchi's model. Moreover, the product of the solubility and diffusivity of progesterone in the polymer matrix was evaluated and found to be 8.1 × 10−7 mg/cm/s. Finally, the effects of fillers on the release behavior were studied. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3040–3044, 2004
Deterioration behavior of cellulose acetate films in acidic or basic aqueous solutions
Authors: Yamashita Yoichiro , Endo Takeshi
Published: January 2004

The deterioration behavior of cellulose acetate (CA) films (degree of substitution = 2.5) was examined in hydrochloric acid (HCl) and sodium hydroxide (NaOH) solutions of various concentrations to determine acid and base catalytic effects in heterogeneous systems at room temperature. With concentrations of 0.5N HCl and 0.01N NaOH and higher, the physical properties of the films changed. The films, recovered after 1–10 days of immersion, were slightly opaque and rubbery from swelling in the solutions before drying. They became brittle and shrank when they dried. For HCl immersion, the weight change of a film depended on the HCl concentration and the immersion time. With 6.0N HCl, the film shape was broken, and a fine powder was deposited in the solution with a recovery of 53.8 wt %. The infrared spectrum of this deposit indicated that it was completely deacetylated cellulose. For NaOH immersion, although the weight change depended on the NaOH concentration, the weight loss reached 40–50% within the first 24 h, and it was constant with respect to the immersion time and base concentration in 0.5N NaOH or NaOH of a higher concentration. The infrared and gel permeation chromatography analyses showed that this deterioration mainly depended on the deacetylation of CA. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3354–3361, 2004
Bismaleimides and biscitraconimides: Synthesis and properties
Authors: Sava M.
Published: January 2004

A series of bismaleimide and biscitraconimide compounds with ester units were synthesized by a condensation reaction between 3‐maleimido benzoic acid chloride or 4‐maleimido benzoic acid chloride and citraconimido benzoyl chloride with 4,4‐(hexafluoroisopropylidene)diphenol and 4,4‐hydroxyphenylsulfone. The monomers were characterized by IR, 1H‐NMR, and elemental analysis. Differential scanning calorimetry, thermogravimetric analysis, and isothermal weight loss were performed to evaluate the thermal properties. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3806–3812, 2004
Permeation of chlorinated hydrocarbons through nylon 6/ethylene–propylene rubber blends
Authors: George Soney C. , Ninan K. N. , Geuskens G. , Thomas Sabu
Published: January 2004

Vapor transport offers one the unique ability to study structure–property relationships in polymers. An analysis of the transport of chlorinated hydrocarbons through nylon/ethylene–propylene rubber (EPR) blend membranes showed us how the permeation behavior varied according to the structure and morphology of the material under study. Binary blends were subjected to solvent transport studies. The solvent uptake increased with EPR content and decreased with nylon content. The behavior varied with the blend morphology. The effects of blend ratio, compatibilization, and dynamic vulcanization on the vapor permeation behavior of nylon/EPR blends were investigated in detail. The results from the vapor permeation studies were complimentary to those of the morphology studies. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3756–3764, 2004
Polyacrylamide–clay nanocomposite materials prepared by photopolymerization with acrylamide as an intercalating agent
Authors: Yeh Jui‐Ming , Liou Shir‐Joe , Chang Ya‐Wen
Published: January 2004

A series of nanocomposite materials consisting of water‐soluble polyacrylamide (PAA) and layered montmorillonite (MMT) clay platelets were prepared by the effective dispersion of the inorganic nanolayers of the MMT clay in the organic PAA matrix via in situ ultraviolet‐radiation polymerization. The acrylamide monomers functioned as both the intercalating agent and the reacting monomers. As a representative procedure for the preparation of the nanocomposites, organic acrylamide monomers were first intercalated into the interlayer regions of acrylamide‐treated organophilic clay hosts, and this was followed by one‐step ultraviolet‐radiation free‐radical polymerization with benzil as a photoinitiator. The as‐prepared polyacrylamide–clay nanocomposite (PCN) materials were subsequently characterized by Fourier transform infrared spectroscopy, wide‐angle powder X‐ray diffraction, and transmission electron microscopy. The effects of the material composition on the thermal stability, optical clarity, and gas‐barrier properties of pristine PAA and PCN materials, in the forms of fine powders and membranes, were also studied by differential scanning calorimetry, thermogravimetric analysis, ultraviolet–visible transmission spectroscopy, and gas permeability analysis. The molecular weights of PAA extracted from PCN materials and pristine PAA were determined by gel permeation chromatography with tetrahydrofuran as an eluant. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3489–3496, 2004
Synthesis, characterization, and thermal properties of poly(methylvinylsilylene‐co‐styrene)
Authors: Ambadas G. , Packirisamy S. , Radhakrishnan T. S. , Ninan K. N.
Published: January 2004

The copolymerization of methylvinyldichlorosilane (MVDCS) and styrene was carried out with various monomer feed ratios under dechlorination conditions with sodium in toluene at 110°C. The copolymers were obtained in 84–95% yields. The copolymerization of MVDCS and styrene with monomer feed ratios of 1 : 0.25 and 1 : 0.5 mainly gave insoluble polymers. The copolymers synthesized with monomer feed ratios of 1 : 1, 1 : 3, and 1 : 7 contained soluble fractions of 3, 26, and 47%, respectively. The copolymers were characterized with infrared, 1H‐NMR, gel permeation chromatography, thermogravimetric analysis, pyrolysis/gas chromatography (PGC), X‐ray diffraction, and elemental analysis (silicon content). 1H‐NMR and PGC studies suggested that the soluble fractions were mainly polystyrene. PGC studies indicated that the copolymers obtained with monomer feed ratios of 1 : 0.25 and 1 : 0.5 did not have any significant amount of polystyryl blocks, whereas the copolymers obtained with higher styrene feed ratios contained appreciable amounts of polystyryl blocks. The composition of the insoluble fractions of the copolymers was obtained from PGC data and was in good agreement with the composition calculated from the silicon content of the copolymers.© 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91:3774–3784, 2004
Crosslinking structures of gelatin hydrogels crosslinked with genipin or a water‐soluble carbodiimide
Authors: Liang Huang‐Chien , Chang Wen‐Hisung , Liang Hsiang‐Fa , Lee Meng‐Horng , Sung Hsing‐Wen
Published: January 2004

It was suggested in our previous studies that carbodiimide‐ and genipin‐crosslinked gelatin hydrogels could be used as bioadhesives to overcome the cytotoxicity problem associated with formaldehyde‐crosslinked gelatin hydrogels. In this study, we investigated the crosslinking structures of carbodiimide‐ and genipin‐crosslinked gelatin hydrogels. We found that crosslinking gelatin hydrogels with carbodiimide or genipin could produce distinct crosslinking structures because of the differences in their crosslinking types. Carbodiimide could form intramolecular crosslinks within a gelatin molecule or short‐range intermolecular crosslinks between two adjacent gelatin molecules. On the basis of gel permeation chromatography, we found that the polymerization of genipin molecules could occur under the conditions used in crosslinking gelatin hydrogels via a possible aldol condensation. Therefore, besides intramolecular and short‐range intermolecular crosslinks, additional long‐range intermolecular crosslinks could be introduced into genipin‐crosslinked gelatin hydrogels. Crosslinking a gelatin hydrogel with carbodiimide was more rapid than crosslinking with genipin. Therefore, the gelation time for the carbodiimide‐crosslinked gelatin hydrogels was significantly shorter than that of the genipin‐crosslinked gelatin hydrogels. However, the cohesive (interconnected) structure of the carbodiimide‐crosslinked gelatin hydrogels was readily broken because, unlike the genipin‐crosslinked gelatin hydrogels, there were simply intramolecular and short‐range intermolecular crosslinks present in the carbodiimide‐crosslinked hydrogel. In the cytotoxicity study, the carbodiimide‐crosslinked gelatin hydrogels were dissolved into small fragments in the cultural medium within 10 min. In contrast, the genipin‐crosslinked gelatin hydrogels remained intact in the medium throughout the entire course of the study. Again, this may be attributed to the differences in their crosslinking structures. The genipin‐crosslinked gelatin hydrogels were less cytotoxic than the carbodiimide‐crosslinked gelatin hydrogels. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 4017–4026, 2004
Effects of the viscosity ratio on polyolefin ternary blends
Authors: Ha M. H. , Kim B. K.
Published: January 2004

Polyolefin binary and ternary blends were prepared from polypropylene (PP), an ethylene–α‐olefin copolymer (mPE), and high‐density polyethylene (HDPE) on the basis of the viscosity ratio of the dispersed phase to the continuous phase. In PP/mPE/HDPE blends, fibrils were observed when the dispersed‐phase (mPE/HDPE) viscosity was less than that of PP, or when the viscosity of mPE was less than that of PP, although the viscosity of mPE/HDPE was greater than that of PP. The notched impact strength and mechanical properties such as the yield strength, flexural modulus, and hardness of PP/mPE binary blends further increased with the addition of HDPE according to the type of HDPE. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 4027–4036, 2004
Gelatin microspheres crosslinked with γ‐ray: Preparation, sorption of proteins, and biodegradability
Authors: Terao Ken , Karino Tomotake , Nagasawa Naotsugu , Yoshii Fumio , Kubo Miyoko , Dobashi Toshiaki
Published: January 2004

A new type of gelatin microspheres was manufactured with the crosslinking method by using γ‐ray irradiation. Microspheres thus obtained were characterized by microscopic observation and enzymatic degradability. The mean diameter of the microspheres was in the range from 2.4 to 3.6 μm and the size distribution was quite small. The size decreased with increasing the shear rate of the emulsifier used in the preparation and was not affected by the radiation dose. The enzymatic degradability decreased with increasing the radiation dose and decreasing the gelatin concentration of the microsphere. In other words, the rate of the enzymatic decomposition of microspheres can be controlled by these two parameters. These trends were consistent with our previous results for the gel sheet made of gelatin. Their sorption of proteins was also investigated with the use of three types of proteins labeled by fluorescent pigment. From the fluorescence micrographs, it was observed that the gelatin microspheres adsorbed only proteins having the opposite charge. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3083–3087, 2004
PE/PE‐g‐MAH/Org‐MMT nanocomposites. II. Nonisothermal crystallization kinetics
Authors: Liang Guodong , Xu Junting , Xu Weibing
Published: January 2004

The nonisothermal crystallization kinetics of high‐density polyethylene (HDPE) and polyethylene (PE)/PE‐grafted maleic anhydride (PE‐g‐MAH)/organic‐montmorillonite (Org‐MMT) nanocomposite were investigated by differential scanning calorimetry (DSC) at various cooling rates. Avrami analysis modified by Jeziorny, Ozawa analysis, and a method developed by Liu well described the nonisothermal crystallization process of these samples. The difference in the exponent n, m, and a between HDPE and the nanocomposite indicated that nucleation mechanism and dimension of spherulite growth of the nanocomposite were different from that of HDPE to some extent. The values of half‐time (t1/2), K(T), and F(T) showed that the crystallization rate increased with the increase of cooling rates for HDPE and composite, but the crystallization rate of composite was faster than that of HDPE at a given cooling rate. Moreover, the method proposed by Kissinger was used to evaluate the activation energy of the mentioned samples. It was 223.7 kJ/mol for composite, which was much smaller than that for HDPE (304.6 kJ/mol). Overall, the results indicated that the addition of Org‐MMT and PE‐g‐MAH could accelerate the overall nonisothermal crystallization process of PE. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3054–3059, 2004
Preparation of polysulfone‐coated chitosan beads by emulsion phase‐inversion method
Authors: Chen F. , Luo G. S. , Wang Y. J.
Published: January 2004

A new coating method of emulsion phase‐inversion method was suggested, and crosslinked chitosan beads coated with a thin polysulfone (PSF) layer were prepared with the new coating method. The emulsion was composed of PSF, dimethylformamide (DMF), paraffin, and Span 80 as the emulsifier. The effects of the swelling ratio (water content), PSF concentration, phase ratio between PSF in DMF solution and the paraffin phase, as well as coating time on the microstructures and thickness of the coating layer were investigated. The microstructures of the coating layer were determined by SEM microphotographs. Experimental results show that the thickness and the microstructures of the coating layer can be easily controlled with the new coating method. By changing the swelling ratio, PSF concentration, phase ratio in the emulsion, and the coating time, the desired coating layer can be achieved. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3542–3548, 2004
Effect of steric hindrance on hydrogen‐bonding interaction between polyesters and natural polyphenol catechin
Authors: Zhu Bo , Li Jianchun , He Yong , Yamane Hideki , Kimura Yoshiharu , Nishida Haruo , Inoue Yoshio
Published: January 2004

The phase behaviors for the blends of poly(3‐hydroxypropionate) (PHP), poly(L‐lactide) (PLLA), poly(D‐lactide) (PDLA), and poly(D,L‐lactide) (PDLLA) with catechin were investigated by differential scanning calorimetry. In PLLA/catechin, PDLA/catechin, and PDLLA/catechin blends, two glass transitions were detected when the catechin content was ≥40 wt %, whereas in PHP/catechin blends only one glass transition was observed over the whole range of blend compositions. The former and the latter results should reflect the inhomogeneous and the homogeneous nature of the blends, respectively, in the amorphous phase. These different phase behaviors should arise from the differences in the chemical structures between PHP and PLLA/PDLA/PDLLA, which dominates the strength and the number of intermolecular hydrogen‐bonding interactions between the ester carbonyl groups of polyesters and the phenol groups of catechin. As detected by FTIR spectroscopy, in comparison with PHP, the steric hindrance of side‐chain methyl groups of PLLA, PDLA, and PDLLA might restrain the formation of hydrogen bonds between their ester carbonyl groups and the phenol hydroxyl groups of catechin, even weakening the strength of such hydrogen bonds. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3565–3573, 2004
Vernonia oil–based acrylate and methacrylate polymers and interpenetrating polymer networks with epoxy resins
Authors: Kolot Victoria , Grinberg Sarina
Published: January 2004

Acrylate and methacrylate monomers were obtained by reacting vernonia oil, a naturally epoxidized oil, with acrylic or methacrylic acid. The highest conversion (85–98%) of epoxy groups was obtained when the reaction was performed with an excess of the carboxylic acid at 100–120°C. The acrylate and methacrylate monomers of vernonia oil were characterized by IR and NMR spectroscopy. These monomers were then cured by sunlight in the presence of benzophenone to produce transparent films. In addition, interpenetrating polymer neworks (IPNs) were prepared in a two‐step technique from the sunlight‐cured methacrylate of vernonia oil, as the elastomeric component, in combination with a cured epoxy resin (a bisphenol A–type resin). Dynamic mechanical analysis showed good compatibility between the networks of the two cured polymers. An IPN with a 1 : 1 composition of the two polymer components exhibited the properties of a reinforced elastomer. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3835–3843, 2004
Study of the thermoformability of ethylene‐vinyl alcohol copolymer based barrier blends of interest in food packaging applications
Authors: Giménez E. , Lagarón J. M. , Cabedo L. , Gavara R. , Saura J. J.
Published: January 2004

The thermoforming capacity of a number of blends of an ethylene‐vinyl alcohol copolymer (EVOH‐32, with 32 mol % ethylene) with amorphous polyamide (aPA) and/or Nylon‐containing ionomer with interest in multilayer food packaging structures have been studied. These blends were vacuum‐thermoformed between 100 and 150°C onto male molds of different shapes and areal draw ratios. It was found that EVOH/aPA extruded blends did not improve the inherently poor formability of EVOH alone. In contrast, significant improvements in thermoformability were achieved by blending EVOH with a compatibilized‐ionomer. Optimum forming capacity was achieved in a ternary blend by addition of a compatibilized‐ionomer to EVOH/aPA blends in the range of 140–150°C. Analysis of wall thickness data obtained in the thermoformed parts showed that wall thickness was significantly affected by the ionomer and amorphous polyamide content in the blend. The ternary blend showed a lower thickness reduction in the critical areas, as well as a higher uniformity in the part. A finite element analysis was used to evaluate the wall thickness distribution and the modeling results were compared with the thermoforming experiments. The simulations were performed for the vacuum‐forming process employing a nonlinear elastic material model. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 96: 3851–3855, 2004
Effect of swelling on the cholesteric structure of ethyl‐cyanoethyl cellulose/crosslinked poly(acrylic acid) composite films
Authors: Wang Xiaohua , Wang Linge , Huang Yong
Published: January 2004

The swelling behavior of ethyl‐cyanoethyl cellulose [(E‐CE)C]/crosslinked poly(acrylic acid) [PAA] cholesteric liquid crystalline composite films and the structural variation of the cholesteric phase during the swelling and the drying process were studied. It was found that the wavelength of the selective reflection of the composite films was shifted to the long wavelength direction during swelling. Both the pitch of the cholesteric phase and the distance between neighboring molecular layers were increased, and the helix axis was inclined after swelling. Moreover, the swelling behavior of the composite films in water was reversible, which means that the optical properties and structural characters of the films could be changed back to their original states after the films were dried from the equilibrium swelling state. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3574–3578, 2004
Effect of hybridization and chemical modification on the water‐absorption behavior of banana fiber–reinforced polyester composites
Authors: Pothan Laly A. , Thomas Sabu
Published: January 2004

The water sorption characteristics of banana fiber–reinforced polyester composites were studied by immersion in distilled water at 28, 50, 70, and 90°C. The effect of hybridization with glass fiber and the chemical modification of the fiber on the water absorption properties of the prepared composites were also evaluated. In the case of hybrid composites, water uptake decreased with increase of glass fiber content. In the case of chemically modified fiber composites, water uptake was found to be dependent on the chemical treatment done on the fiber surface. Weight change profiles of the composites at higher temperature indicated that the diffusion is close to Fickian. The water absorption showed a multistage mechanism in all cases at lower temperatures. Chemical modification was found to affect the water uptake of the composite. Among the treated composites the lowest water uptake was observed for composites treated with silane A1100. Finally, parameters like diffusion, sorption, and permeability coefficients were determined. It was observed that equilibrium water uptake is dependent on the nature of the composite and temperature. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3856–3865, 2004
Evaluation of the thermal and mechanical properties of poly(ε‐caprolactone), low‐density polyethylene, and their blends
Authors: Rosa D. S. , Neto I. Chiovatto , Calil M. R. , Pedroso A. G. , Fonseca C. P. , Neves S.
Published: January 2004

The thermal and mechanical properties of low‐density polyethylene (LDPE), poly(ε‐caprolactone) (PCL), and their blends were evaluated. Differential scanning calorimetry showed that increasing the PCL content of the blend did not change the LDPE melting temperature, but reduced the crystallinity by up to 16.8%. This behavior was related to interactions between the PCL chains and the crystalline phase of LDPE. Tensile strength and elongation at break values for the blends were lower than those for the pure polymers, which suggested an incompatibility between the polymers. The values for Young's modulus under tensile increased when PCL was added to LDPE. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91:3909–3914, 2004
Preferential mineralization of CaCO3 layers on polymer surfaces from CaCl2 and water‐soluble carbonate salt solutions supersaturated by poly(acrylic acid)
Authors: Iwatsubo Takashi , Sumaru Kimio , Kanamori Toshiyuki , Yamaguchi Tomohiko , Sinbo Toshio
Published: January 2004

CaCO3 was mineralized from solutions supersaturated only by poly(acrylic acid) (PAA), without bubbling any CO2 gas in the solution. For example, a layer of CaCO3 was built up on the surface of a chitosan membrane from a supersaturated aqueous solution containing CaCl2, Na2CO3, and PAA. In this newly developed method, the PAA alone suppresses the precipitation of CaCO3 from the bulk solution, and therefore, increases the supersaturated concentration. This concentration is estimated to be the same order as that attained in the method in which both CO2 gas and PAA were used. At the same time, PAA supplies nucleation fields by forming a polymer complex with chitosan. The crystal system obtained was different from those obtained when using CO2 gas. Self‐organization of aragonite crystallites led to the formation of uniform, concentric, or branching patterns in the surface‐domain structure. These patterns had morphologies similar to those discovered by other researchers, typically in the crystallization of ascorbic acid. Thicker layers of CaCO3 could be formed on chitosan membranes, the surfaces of which had been converted to a polyelectrolyte complex (PEC) by exposure to PAA solution before the onset of mineralization. Under certain conditions, the CaCO3 layer had a small spherical curvature, similar to a half‐lens, and generated Newton's ring pattern from the interference fringes of visible light. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91:3627–3634, 2004
Effect of crosslinking concentration on the micelle formation inside the polymer gel network and mechanical properties of sensitive hydrogel polymer in contact with surfactant solutions
Authors: Mounir A. , Darwish N. , Shehata A.
Published: January 2004

The variation of the swelling and mechanical properties of crosslinked nonionic poly (N‐isopropylacrylamide) (NIPA) polymer gel immersed in tetradecyl dimethylaminoxide (C14DMAO) surfactant solutions at 0.1M NaCl, synthesized at different crosslinker concentrations was investigated. Also the aggregation behavior of C14DMAO surfactants inside and outside the polymer hydrogels has been studied through solubilization of Sudan III dye. The solubilization experiments indicated that, at the degree of ionization α = 0.5 and 1, the surfactant concentration inside the gel is lower than that outside the gel at low crosslinker concentration. In the case of the nonionic C14DMAO at α = 0, on the other hand, the surfactant concentration inside the gel and outside the gel was almost identical, irrespective of the crosslinker concentration. The elastic modulus, G, of the network polymer gel in contact with the C14DMAO solutions of 5 and 10 mM concentration was larger than that of the water solution irrespective of the degree of ionization (α = 0 and 0.5). This difference in the elastic modulus, G, of network polymer gel may be attributed to the change of the rigidity of the polymer network. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3921–3926, 2004
Hydroxymethylation and polymerization of plant oil triglycerides
Authors: Eren Tarik , Küsefoğlu Selim H.
Published: January 2004

The ene reaction between plant oil triglycerides (such as soybean and sunflower oils) and paraformaldehyde was used to introduce a homoallylic hydroxyl functionality on the triglyceride. Paraformaldehyde and triglyceride were reacted in the presence of a Lewis acid catalyst, ethylaluminum dichloride, and hydroxymethyl derivatives were obtained at yields of 42 and 55% for sunflower oil and soybean oil, respectively. In the next step, hydroxymethyl products were reacted with maleic anhydride at 100°C to produce the maleate half esters. The average number of maleate groups per triglycerides was found to be 1.7 for soybean oil and 1.3 for sunflower oil. In the final step, the free‐radical–initiated copolymerization of the maleinized triglycerides with styrene produced rigid polymers. Characterization of new monomers and polymers was done by 1H‐NMR, 13C‐NMR, and infrared and mass spectrometries. The swelling behavior of the crosslinked network polymers was determined in different solvents. The glass‐transition temperature of the cured resin was also determined by differential scanning calorimetry to be 40°C for soybean‐based polymer and 30°C for sunflower‐based polymer. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 4037–4046, 2004
Polyethylene/maleic anhydride grafted polyethylene/organic‐montmorillonite nanocomposites. I. Preparation, microstructure, and mechanical properties
Authors: Liang Guodong , Xu Junting , Bao Suping , Xu Weibing
Published: January 2004

In this study, three cationic surfactants (hexadecyltrimethylammonium chloride, hexadecyldimethylbenzylammonium chloride, and octadecyltrimethylammonium chloride) were used to modify montmorillonite and polyethylene (PE)/maleic anhydride grafted polyethylene (PE‐g‐MAH)/organic‐montmorillonite (Org‐MMT) nanocomposites, prepared by two blending processes (direct‐melt blending and solution blending). X‐ray diffractometry and transmission electron microscopy were used to investigate the intercalation behavior and microstructure of composites. Mechanical properties were also tested. It was found that the intercalation effect of PE/PE‐g‐MAH/Org‐MMT could be enhanced by increasing the content of PE‐g‐MMT, using the silicate modified by a cationic surfactant with a benzyl group or long alkyl chain, adopting the solution‐blending method or using high‐density polyethylene as matrix. The degree of crystallinity of composites and the crystalline thickness perpendicular to the crystalline plane [like (110) and (200)] decreased with increasing amounts of PE‐g‐MAH and, under certain prescription, the crystalline thickness of the composite made by the solution method was much smaller than that made by direct‐melt blending. This clearly showed that Org‐MMT and PE‐g‐MAH had a heterogeneous nucleation effect on crystallization of PE from the melt, resulting in a decrease of crystalline thickness, and the heterogeneous nucleation effect was more evident in the nanocomposite made by the solution‐blending method than in that made by the direct‐melt intercalation process. The tensile strength initially increased and then decreased with increasing contents of PE‐g‐MAH. The maximum value in tensile strength (23.3 MPa) was achieved when the concentration of PE‐g‐MAH was 6 wt %. The impact strength increased concomitantly with the content of PE‐g‐MAH; it was 122.2 J/m when the concentration of PE‐g‐MAH was 9 wt %.© 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3974–3980, 2004
Simultaneous covalent immobilization of glucose oxidase and catalase onto chemically modified acrylonitrile copolymer membranes
Authors: Godjevargova T. , Dayal Rajeshwar , Marinov Ivaylo
Published: January 2004

Ultrafiltration membranes from acrylonitrile copolymer were chemically modified with different concentrations of hydrogen peroxide (from 5 to 30% H2O2). The amount of the amide groups in the modified membranes was determined. The water flow and permeability coefficients of the initial and modified membranes were also researched. The modified membranes were used as carriers for covalent immobilization of the dual enzyme system of glucose oxidase and catalase (GOD+CAT). It was found that the best matrices for immobilization of the dual system were membranes modified with 20% H2O2 and the optimal activity ratio was GOD : CAT = 1 : 5. The glucose conversion efficiency with the dual enzyme system was twice as high as that of bound GOD alone. Some of the basic characteristics (optimum pH, optimum temperature, pH, temperature stability, and storage stability) of the dual enzyme system were determined and compared with characteristics of free and bound enzymes. The catalytic parameters of the enzyme reaction (Km and Vmax) were determined with GOD immobilized alone and with the dual system GOD+CAT. The higher rate observed with the dual enzyme system clearly showed the advantage and the efficiency of the immobilized system. Glucose oxidase without catalase was deactivated by H2O2 more rapidly than the immobilized dual GOD+CAT system. These experimental evidences can be explained by the protecting effect of catalase on glucose oxidase from inhibition by H2O2. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 4057–4063, 2004
Electrochemically synthesized polypyrrole and Cu‐plated nylon/spandex for electrotherapeutic pad electrode
Authors: Kim Seong Hun , Oh Kyung Wha , Bahk Jae Hyon
Published: January 2004

Electroconductive fabrics were prepared to improve the properties of conductive electrode pad material used for electrotherapy when it is subjected to various movements of the human body. Highly stretchable and conductive fabrics were prepared by in situ electrochemical polymerization of polypyrrole (PPy) on nylon/spandex stretchable fabric in aqueous solutions with 0.05M pyrrole and 0.05M anthraquinone‐2‐sulfonic acid, sodium salt monohydrate (AQSA) at room temperature for 2 h. Electroless Cu plating was also applied after chemical polymerization of PPy to improve the conductivity of the fabric pad. Performance of prepared stretchable conductive fabric pad was evaluated in terms of conductivity changes as a function of extension and continuous current application time, and clinical test. As a result, the fabric conductivity was well maintained with extension up to 60% and prolonged treatment time over 30 min. The effect of transcutaneous electrical nerve stimulation (TENS) was observed with prepared TENS pad in this study and conventional TENS pad for medical use. The significant effect of TENS was observed with a pad made of conductive fabric by Cu plating and a conventional TENS pad (P < 0.05, respectively). Even though the efficiency of an experimental pad made of fabric composite with electrochemically polymerized PPy was not as good as conventional TENS pad for medical use in this experiment, it can possibly be used for other applications where relatively low‐strength electrical pulse is required. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 4064–4071, 2004
Study on long fiber–reinforced thermoplastic composites prepared by in situ solid‐state polycondensation
Authors: Yan Weixia , Han KeQing , Qin LiuLiang , Yu MuHuo
Published: January 2004

Long glass fiber–reinforced thermoplastic composites were prepared by a new process, in situ solid‐state polycondensation (INSITU SSP). In this process reinforcing continuous fibers were impregnated by the oligomer of PET melt, and then the impregnated continuous fibers were cut to a desired length (designated prepreg); finally, the prepreg was in situ polymerized in the solid state to form the high molecular weight matrix. SEM, FTIR spectra, short‐beam shear stress test, flexural strength test, impact strength test, and the intrinsic viscosity measurement were used to investigate the wetting and interfacial adhesion, the mechanical properties of the composite, and the molecular weight of matrix resin in the composite. The results showed that the molecular weight of PET in the matrix resin and mechanical properties could be adjusted by controlling the SSP time and that the high level of interfacial adhesion between reinforcing fibers and matrix resin could be achieved by this novel INSITU SSP process, which are attributed to the good wetting of reinforcing fibers with low molecular weight oligomer melt as the impregnation fluid, the in situ formation of chemical grafting of oligomer chains onto the reinforcing fiber surface, and the in situ formation of the high molecular weight PET chains in the interphase regions. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91:3959–3965, 2004