bluuebunny/crossref_metadata_2025 huggingface dataset:
Rice bran‐filled biodegradable low‐density polyethylene films: Development and characterization for packaging applications
Authors: George Johnsy , Kumar R. , Jayaprahash C. , Ramakrishna A. , Sabapathy S. N. , Bawa A. S.
Published: September 2006

Rice bran was incorporated into low‐density polyethylene (LDPE) at different concentrations by compounding in a twin‐screw extruder and blown into films of uniform thickness. The rice bran incorporation influenced physical, mechanical, barrier, optical, thermal properties, and biodegradation of LDPE. The mechanical and optical properties decreased as the percentage of rice bran increased. The effect of rice bran on the morphology of LDPE blends was examined using scanning electron microscopy. Oxygen transmission rate and water vapor transmission rate increased with the increased content of rice bran. Addition of rice bran did not alter the melting temperature (Tm) of the blends; however the thermal stability decreased, while glass transition temperature (Tg) increased. Kinetics of thermal degradation was also investigated and the activation energy for thermal degradation indicated that for up to 10% filler addition, the dispersion and interfacial adhesion of rice bran particles in LDPE was good. Aerobic biodegradation tests using municipal sewage sludge and biodegradation studies using specific microorganism (Streptomyces species) revealed that the films are biodegradable. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4514–4522, 2006
Effect of carboxyl on vulcanization and mechanical properties of carboxylated acrylic rubber prepared by 60Co‐γ‐ray‐induced polymerization
Authors: Wang Weiwei , Chang Zhenqi , Wang Mozhen , Zhang Zhicheng
Published: September 2006

Acrylic acid carboxylated acrylic rubber (ACM) and itaconic acid carboxylated acrylic rubber were prepared by 60Co‐γ‐ray‐induced emulsion copolymerization. The polymers were characterized using FTIR and 13C NMR spectroscopies. The acid value was determined with nonaqueous titration method. The molecular weight and the polydispersity index of the polymers were measured using gel permeation chromatography. The influence of the cure‐site (carboxyl) on the vulcanization and mechanical properties of the ACM was researched by means of rheometric study, gel fraction analysis, mechanical property tests, and dynamic mechanical thermal analysis. The results show that the crosslink density of polymers increases with amounts of the carboxyl cure‐site. The itaconic acid carboxylated ACM has better cure characteristics and mechanical properties than the acrylic acid carboxylated ACM has. In addition, the comparison of ACM prepared by 60Co‐γ‐ray‐induced polymerization with ACM prepared by chemical‐initiator‐induced polymerization has been investigated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5587–5594, 2006
Novel organic modification of montmorillonite in hydrocarbon solvent using ionic liquid‐type surfactant for the preparation of polyolefin–clay nanocomposites
Authors: Ding Yunsheng , Guo Cunyue , Dong Jin‐Yong , Wang Zigang
Published: September 2006

The possibility of organic modification of montmorillonite (MMT) in hydrocarbon solvents by employing ionic liquid‐type surfactants was investigated. As a first example, 1‐methyl‐3‐tetradecylimidazolium chloride ([C14mim]+Cl−) was used to treat pristine MMT in xylene. The dispersion of MMT in xylene was significantly improved, the collected organifically modified MMT displayed a sufficiently enlarged interlayer spacing. The novel art of MMT organic modification is specifically advantageous to the preparation of polyolefin‐based nanocomposites. A polypropylene/MMT nanocomposite was exemplarily prepared by directly dissolving polypropylene in the MMT modification system and found to possess an excellent thermal stability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4314–4320, 2006
Preparation of magnetic poly(glycidyl methacrylate) microspheres by emulsion polymerization in the presence of sterically stabilized iron oxide nanoparticles
Authors: Horák Daniel , Chekina Nataliya
Published: September 2006

With the aim to synthesize water‐dispersible superparamagnetic nanoparticles, iron oxide was precipitated in aqueous solution of dextran, (carboxymethyl) dextran (CM‐dextran), (DEAE‐dextran), or D‐mannose. Glycidyl methacrylate (GMA) was emulsion‐polymerized in the presence of the nanoparticles and the effect of iron oxide modification on the product properties was investigated. The main factors affecting the morphology, size, and size distribution of the latex particles are the type and concentration of emulsifier (Disponil AES 60, Tween 20, Triton X‐100) and initiator [ammonium persulfate (APS) and 4,4′‐azobis(4‐cyanovaleric acid) (ACVA)]. Disponil AES 60 and ACVA are the preferred emulsifier and initiator, respectively, because oxirane groups hydrolyzed during the APS‐initiated polymerization. Up to some 5 wt % of iron was found in poly(glycidyl methacrylate) (PGMA) microspheres obtained by emulsion polymerization in the presence of dextran‐coated iron oxide and emulsified with Disponil AES 60. The size of magnetic PGMA microspheres could be controlled in the range ˜ 70–400 nm. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4348–4357, 2006
The influences of fiber feature and polymer melt index on mechanical properties of sugarcane fiber/polymer composites
Authors: Lu John Z. , Wu Qinglin , Negulescu Ioan I. , Chen Yan
Published: September 2006

The fiber characteristics (i.e., the fiber type, morphology, and dimension) and polymer melt flow index (MFI) significantly affected mechanical properties of sugarcane fiber/HDPE composites. The length and diameter of sugarcane fibers followed a lognormal distribution before and after compounding. The long fibers had a significant reduction in the dimension and aspect ratio during compounding. However, the short fibers had close values in these two properties before and after compounding. For the resultant sugarcane fiber/polymer composites, the HDPE resins with a low MFI value presented high tensile and impact strengths. Because of high sugar content, the pure rind fiber had a poor performance as filler in the HDPE resins with respect to the raw bagasse fiber and alkali‐extracted bagasse fiber. On the other hand, the aspect ratio was proportional to the mechanical performance of the fibers in the HDPE resins. As a result, the fibers with a large aspect ratio and low sucrose content improved the strength properties of the resultant composites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5607–5619, 2006
Crosslinking of corn starch with sodium trimetaphosphate in solid state by microwave irradiation
Authors: Gui‐Jie Mao , Peng Wang , Xiang‐Sheng Meng , Xing Zhang , Tong Zheng
Published: September 2006

Corn starch was crosslinked with sodium trimetaphosphate (STMP) in solid state under microwave irradiation to improve the degree of substitution (DS) and decrease the reaction time. The effects of modification factors on the crosslinking of starch were systematically studied. It was found that the microwave irradiation provided a convenient and efficient method to prepare crosslinked starch with sufficient DS. The DS value of crosslinked starches obtained by microwave irradiation was significantly improved and the reaction time was also dramatically decreased to achieve an appropriate DS value by microwave irradiation, when compared with using traditional method. The high microwave power provided faster reaction kinetics to obtain the desired DS value at an identical reaction condition. If the reaction temperature is lower than the decomposition temperature of crosslinked starch, the higher DS value can be achieved at the higher microwave power. It was detected that the DS data obtained by reacting intermittently was higher than those by reacting continuously. It was also noticed that DS data varied drastically with the increasing of the amount of STMP and sodium carbonate. The swelling ratio of crosslinked starch in water was lower than that of native starch because of the nongelatinization of highly crosslinked starch. SEM analysis indicated that the crosslinking of corn starch by microwave irradiation caused no significant changes in the microstructure of starch granules. Light microscope analysis also showed the uniformity of so‐prepared crosslinked corn starch applying microwave irradiation. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5854–5860, 2006
Electrochemical characteristics and catalytic activity of polyaniline doped with ferrocene perchlorate
Authors: Wen‐Zhi Zhang , Xian‐Wen Kan , Shou‐Feng Jiao , Jin‐Gao Sun , Dong‐Sheng Yang , Bin Fang
Published: September 2006

A new‐doped method based on electrochemical polymerization of aniline in the presence of ferrocene perchlorate and perchloric acid was presented. Polyanilines (PAn and PAnFc) were polymerized in the solution of perchloric acid and the solution containing ferrocene perchlorate and perchloric acid, respectively. Both flame atomic absorption spectrometry and infrared spectrum indicated that ferrocene perchlorate was assured to be doped into the polyaniline. We presumed that ferrocene perchlorate was combined via electrostatic adsorption onto the chain of polyaniline. The effect of pH on the electrochemical characteristics of PAn and PAnFc was studied by cycle voltammetry. Compared with PAn prepared in the absence of ferrocene perchlorate, PAnFc prepared in the presence of ferrocene perchlorate has a rather high electrochemical activity at pH > 4. The electrochemical oxidation of ascorbic acid (AA) on both PAn film and PAnFc film modified Pt electrode was also performed. The results indicated that the catalytic activity of the PAnFc film to AA was better than that of the PAn film. The anodic peak currents of AA (measured by constant potential amperometry) increased linearly with the concentration of AA in the range of 8.0 × 10−5–1.0 × 10−2 mol/L. The detection limit (S/N = 3) obtained was 1.0 × 10−5 mol/L. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5633–5639, 2006
Polyester composites reinforced with noncrimp stitched carbon fabrics: Mechanical characterization of composites and investigation on the interaction between polyester and carbon fiber
Authors: Cecen Volkan , Sarikanat Mehmet , Seki Yoldaş , Govsa Tugrul , Yildiz Hasan , Tavman Ismail H.
Published: September 2006

The primary purpose of the study is to investigate the anisotropic behavior of different noncrimp stitched fabric (NCF) reinforced polyester composites. Carbon fiber composite laminates were manufactured by vacuum infusion of polyester resin into two commonly used advanced noncrimp stitched carbon fabric types, unidirectional and biaxial carbon fabric. The effects of geometric variables on composite structural integrity and strength were illustrated. Hence, tensile and three‐point bending flexural tests were conducted up to failure on specimens strengthened with different layouts of fibrous plies in NCF. In this article an important practical problem in fibrous composites, interlaminar shear strength as measured in short beam shear tests, is discussed. The fabric composites were tested in three directions: at 0°, 45°, and 90°. Extensive photomicrographs of multilayered composites resulting from a variety of uniaxial loading conditions were presented. It was observed that broken fibers recede within the matrix in composites with weak interfacial bond. Another aim of the present work was to investigate the interaction between carbon fiber and polyester matrix. The experiments, in conjunction with scanning electron photomicrographs of fractured surfaces of composites, were interpreted in an attempt to explain the instability of polyester‐resin–carbon‐fiber interfaces. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4554–4564, 2006
Effect of chemical treatment of wood flour on the properties of styrene butadiene rubber/polystyrene composites
Authors: Mansour S. H. , El‐Nashar D. E. , Abd‐El‐Messieh S. L.
Published: September 2006

Composites from SBR/PS blend and the chemically treated wood flour have been prepared. The materials used for such treatment are NaOH, MAN, MAN‐glycidyl methacrylate, and silane coupling agent, used to improve the dispersion of wood flour in the SBR/PS blend. The effects of chemical treatment on curing characteristics, and physicomechanical and electrical properties of SBR/PS composites were studied. The rheological as well as the mechanical parameters were improved by using the modified wood flour with MAN‐glycidyl methacrylate (SMG), followed by SM obtained at 15 phr, while the other treatments slightly affect these parameters. The permittivity ϵ′ and dielectric loss ϵ″ were measured in the frequency range from 100 Hz up to 100 kHz and at temperatures ranging from 30 up to 90°C. The dielectric investigations indicate that the samples containing wood flour treated with both SMG and SM increase the values of ϵ′ and decrease those of ϵ″, which allow such samples to be used in insulation purposes. The increase in the relaxation time and the crosslinking density ν for such composites indicate the increase in filler–polymer interaction rather than filler–filler interaction. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5861–5870, 2006
Syntheses and properties of novel polyimides derived from 2‐(4‐Aminophenyl)‐5‐aminopyrimidine
Authors: Xia Aixiang , Lü Guanghua , Qiu Xuepeng , Guo Haiquan , Zhao Jianying , Ding Mengxian , Gao Lianxun
Published: September 2006

2‐(4‐Aminophenyl)‐5‐aminopyrimidine (4) is synthesized via a condensation reaction of vinamidium salts and amidine chloride salts, followed by hydrazine palladium catalyzed reduction. A series of novel homo‐ and copolyimides containing pyrimidine unit are prepared from the diamine and 1,4‐phenylenediamine (PDA) with pyromellitic dianhydride (PMDA) or 3,3′,4,4′‐biphenyl tertracarboxylic dianhydride (BPDA) via a conventional two‐step thermal imidization method. The poly(amic acid) precursors had inherent viscosities of 0.97–4.38 dL/g (c = 0.5 g/dL, in DMAc, 30°C) and all of them could be cast and thermally converted into flexible and tough polyimide films. All of the polyimides showed excellent thermal stability and mechanical properties. The glass transition temperatures of the resulting polyimides are in the range of 307–434°C and the 10% weight loss temperature is in the range of 556–609°C under air. The polyimide films possess strength at break in the range of 185–271 MPa, elongations at break in the range of 6.8–51%, and tensile modulus in the range of 3.5–6.46 GPa. The polymer films are insoluble in common organic solvents, exhibiting high chemical resistance. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5871–5876, 2006
Graft polymerization of acrylic acid onto polyphenylene sulfide nonwoven initiated by low temperature plasma
Authors: Li Ying‐na , Sun Yuan , Deng Xin‐hua , Yang Qing , Bai Zhi‐yong , Xu Zhi‐bin
Published: September 2006

Graft copolymerization of acrylic acid (AA) onto polyphenylene sulfide (PPS) nonwoven initiated by low temperature plasma was studied. The effects of various conditions on graft reaction and the grafting rate were investigated. SEM images showed that PPS nonwoven was grafted, and the graft copolymerization only occurred on the surface of PPS. It may be due to the chain transference going with the graft copolymerization. It was found that with the increasing of plasma power, treatment time, space between electrodes, monomer concentration, and temperature of graft polymerization, the grafting rate increased at first, went to the top, and then decreased. The PPS nonwoven surface graft reaction could be optimized by the following processing conditions: 120 s of plasma treatment time, 50 W of plasma power, 1.5 cm of space between electrodes, 30% (w/w) of monomer concentration, and 50°C of temperature of graft polymerization. Measurement of XPS showed that the peak of C1s of graft polyacrylic acid was existed, and the peak area increased with the increase of the grafting rate. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5884–5889, 2006
Preparation and deodorizing performance of a novel air‐purifying material
Authors: Yao Yu‐Yuan , Chen Wen‐Xing , Lu Shen‐Shui
Published: September 2006

Two kinds of water‐soluble metallophthalocyanine derivatives, binuclear phthalocyaninecobalt(II) (Co2Pc2) and binuclear phthalocyanineiron(III) (Fe2Pc2), were supported on cationic wool fibers (CWF) to obtain a novel air‐purifying material, binuclear metallophthalocyanine fibers (Mt2Pc2CWF), and the optimal supporting conditions were pH 5, 100°C, and 60 min. Mt2Pc2CWF could eliminate efficiently the malodors of methanthiol and hydrogen sulfide at room temperature by cata lytic oxidation reaction used oxygen in atmosphere as oxidant. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4378–4382, 2006
Preparation of uniform poly(glycidyl methacrylate) porous microspheres by membrane emulsification–polymerization technology
Authors: Wang Renwei , Zhang Ying , Ma Guanghui , Su Zhiguo
Published: September 2006

Uniform poly(glycidyl methacrylate‐divinyl‐benzene) (P(GMA‐DVB)) and poly(glycidyl methacrylate‐ethylene dimethacrylate) (P(GMA‐EGDMA)) porous microspheres with several 10 μm were successfully prepared by membrane emulsification–polymerization technology. Conventional suspension polymerization method was first investigated by examining the effects of recipe components on the morphologies of P(GMA‐DVB), including stabilizer, diluent, and crosslinker to select a optimum recipe. The membrane emulsification–polymerization process was developed to prepare uniform PGMA porous microspheres as the following: the oil phase composed of monomer, diluent and initiator was pressed through membrane pores into the aqueous phase to form uniform droplets, and subsequent suspension polymerization was carried out. GMA and 4‐methyl‐2‐pentanol in the selected recipe were relatively hydrophilic, and therefore oil phase could wet the hydrophilic glass membrane and bring about polydispersed droplets. However, when isooctane was added as a component of diluents, the uniform droplets could be prepared by membrane emulsification method. In the membrane emulsification–polymerization, the coagulation between microspheres obviously decreased while yield of microspheres slightly increased. To extend the application of PGMA, as a trail, uniform P(GMA‐EGDMA) porous microspheres were also successfully prepared by membrane emulsification–polymerization with a isooctane contained diluent, even though EGDMA was more hydrophilic than DVB. Therefore, recipe was found the important factor to prepare uniform PGMA porous microspheres using membrane emulsification–polymerization method. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5018–5027, 2006
Nonisothermal melt‐crystallization kinetics of hydroxyapatite‐filled poly(3‐hydroxybutyrate) composites
Authors: Tang C. Y. , Chen D. Z. , Tsui C. P. , Uskokovic P. S. , Yu Peter H. F. , Leung Mason C. P.
Published: September 2006

The knowledge of biomedical implants ranging from drug delivery devices to tissue engineering and based on bioresorbable polymer composites is increasing, but the study of the crystallization kinetics of these kinds of composites is seldom a concern. The focus of our experimental research was the nonisothermal‐crystallization behavior of poly(3‐hydroxybutyrate) (PHB)/hydroxyapatite (HA) composites, which was monitored by means of differential scanning calorimetry at different cooling rates. Various macrokinetic models were applied to describe the process of nonisothermal crystallization. The results showed that the modified Avrami model and Mo's approach could describe the nonisothermal crystallization of the composites very well, but the Ozawa analysis alone was thought to be rather inapplicable. The values of the half‐time and kinetic crystallizability showed that the crystallization rate increased with increasing cooling rates for both PHB and the composites. The HA particles served as additional nucleation sites, and low levels of HA resulted in dramatic increases in the crystallization rate with respect to pure PHB; however, high HA contents (> 20 wt %) clearly retarded the growth process. The activation energy for nonisothermal crystallization was evaluated with the Kissinger method and was found to vary with the incorporation of HA. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:5388–5395, 2006
Improved pharmacokinetics and stability properties of catalase by chemical glycosidation with end‐group activated dextran
Authors: Villalonga Reynaldo , Valdivia Aymara , Pérez Yunel , Chongo Bertha
Published: September 2006

Catalase was chemically modified with a monoactivated dextran derivative having a carboxylate group at its reducing end residue. The modified enzyme retained 77% of its initial specific activity and was 3‐fold more resistant to tryptic degradation. The plasma half‐life time was increased to 7.3‐fold after glycosidation. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4573–4576, 2006
Mass transfer and radical flux effects in dispersed‐phase polymerization of isooctyl acrylate
Authors: Back Alan J. , Schork F. Joseph
Published: September 2006

The kinetics of dispersed phase polymerization of a highly water‐insoluble monomer (isooctyl acrylate) were explored in emulsion, miniemulsion, and microsuspension polymerization. The effects of monomer water solubility and choice of initiator (oil‐ vs. water‐soluble) strongly impact the final product (particle size and molecular weight distribution). For emulsion polymerization, as the surfactant concentration was increased, there was a transition from homogenous to micellar nucleation near the CMC, then a drop in nucleation rate at high surfactant concentration due to insufficient radical flux to support more nucleation. For miniemulsion polymerization, a slow rate of growth of (droplet) nucleation with surfactant concentration was found, followed (at the CMC) by an increase in the rate of nucleation with added surfactant as the mode of nucleation switched to micellar. The conversion‐time kinetics of microsuspensions could be modeled with a bulk polymerization model. IOA is sufficiently insoluble in the aqueous phase that emulsion polymerization may or may not be reaction limited. The presence of a stabilizer such a PAA, the use of an oil‐soluble initiator such as BPO, and the insolubility of IOA in the aqueous phase all push the polymerization locus toward droplet (microsuspension) nucleation and bulk kinetics.© 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5649–5666, 2006
Gum arabic–acrylic superabsorbing hydrogel hybrids: Studies on swelling rate and environmental responsiveness
Authors: Zohuriaan‐Mehr M. J. , Motazedi Z. , Kabiri K. , Ershad‐Langroudi A. , Allahdadi Iraj
Published: September 2006

The swelling rate and the environmental sensitivity of novel superabsorbent gum arabic–acrylic hydrogel hybrids were investigated. The swelling kinetics of the hydrogel hybrids was studied by means of a Voigt‐based viscoelastic model. The effects of concentration of the initiator, crosslinker, and the monomer ratio on the swelling rate were studied. The superswelling properties of the hydrogel hybrids were evaluated in various environmental pH, salinity and solvent–water mixtures. The optimally prepared hydrogel, MR5, showed a reproducible on–off switching behavior when the swelling medium was alternatively changed between distilled water and alkaline solutions. The hydrogel hybrid MR5 was also tested to be swollen and deswollen alternatively in distilled water and sodium chloride solution. The sorption–desorption behavior was found to be quite repeatable. A similar capability was interestingly observed when a calcium chloride solution with the same molar concentration was used. The swelling changes of the hydrogel hybrid were examined in various water–solvent systems including the aqueous solutions of methanol, ethanol, acetone, ethylene glycol, glycerol, and dimethylsulfoxide. One and/or two volume‐phase transitions were induced by the nonsolvents. The transitions were explained according to the solubility parameters of the solvents and water–solvent mixtures. The swelling–deswelling capability of the hydrogel in alternatively changed solvent–water mixtures was also studied. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5667–5674, 2006
Asymmetric membranes fabricated from poly(acrylonitrile‐co‐N‐vinyl‐2‐pyrrolidone)s with excellent biocompatibility
Authors: Wan Ling‐Shu , Xu Zhi‐Kang , Huang Xiao‐Jun
Published: September 2006

Poly(acrylonitrile‐co‐N ‐vinyl‐2‐pyrrolidone)s (PANCNVPs) show excellent biocompatibility. In this work, PANCNVPs with different contents of N‐vinyl‐2‐pyrrolidone (NVP) were fabricated into asymmetric membranes by the phase inversion method. The surface chemical composition of the resultant membranes was determined by Fourier transform infrared spectroscopy–attenuated total reflection. Field emission scanning electron microscopy was used to examine the surface and cross section morphologies of the membranes. It was found that the morphologies hardly change with the increase of NVP content in PANCNVP, while the deionized water flux increases remarkably and the bovine serum albumin (BSA) retention decreases slightly. Experiment of dynamic BSA solution filtration was carried out to evaluate the antifouling properties of the studied membranes. The relative flux reduction of PANCNVP membrane containing 30.9 wt % of NVP is 25.9%, which is far smaller than that of the polyacrylonitrile membrane (68.8%). Results deduce that this improvement comes from the excellent biocompatibility of NVP moieties instead of the hydrophilicity change, because the water contact angles of these membranes fluctuate between 60 and 70°. Results from the membranes using poly(N‐vinyl‐2‐pyrrolidone) (PVP) as an additive confirm that, to a certain extent, the PANCNVP membranes show the advantages of antifouling compared with the polyacrylonitrile/PVP blending membrane. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4577–4583, 2006
One‐pot synthesis of polyetherimides from bis(chlorophthalimide) and dichlorodiphenylsulfone in diphenylsulfone
Authors: Shang Zhenping , Lü Changli , Zhao Jianying , Yan Jingling , Ding Mengxian , Gao Lianxun
Published: September 2006

Polyetherimides and copolymers have been synthesized in one pot from bis(chlorophthalimide), dichlorodiphenylsulfone, and bisphenolate using diphenylsulfone as the solvent. The inherent viscosities of the obtained polyimides are in the range of 0.32–0.72 dL/g, and the structures of polyimides were confirmed by IR and elemental analyses. All of the polyimides have good solubility in common organic solvents. The 5% weight‐loss temperatures of the polyimides were 429–507°C in air. The glass transition temperatures (Tg) of 4,4′‐(9‐fluorenylidene) diphenol‐based polyimides are in the range of 253–268°C. TheTgof bisphenol A‐based polyimides is in the range of 198–204°C, while theTgchange inconspicuously when the ratios of diphenylsulfone increase. The wide‐angle X‐ray diffraction showed that all polyimides prepared are amorphous. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4584–4588, 2006
Premature vulcanization behaviors of rubber compounds under high shear rates processing
Authors: Lin Yaling , Zhang Anqiang , Wang Lianshi
Published: September 2006

The premature vulcanization behaviors of six kinds of common rubber (NR, BR, SBR, NBR, CR, and EPDM) compounds containing curing agents were studied in a wide processing temperature range (100–140°C) and rotor speed range (30–70 rpm) using a Brabender torque rheometer, which can supply the rubber compounds a high shear rates processing condition. After comparison with the Mooney scorch time (MSt5), it is shown that Mooney scorch time cannot predict the premature vulcanization time under high shear rate processing. Six models were put forward based on the data obtained from the Brabender mixing head. The regression analysis and variance analysis showed that these models could simulate the premature vulcanization time very well. An explanation was given based on the reactivity and of rubber chain segments: the increasing reactivity and the impact probability of reactive rubber chain segment under high shear rate is the main reason of shorter scorch time of rubber compounds under high shear rate internal mixing. © 2006 Wiley Periodicals, Inc. JAppl PolymSci 102: 5414–5420, 2006
Change of membrane performance due to chlorination of crosslinked polyamide membranes
Authors: Kwon Young‐Nam , Tang Chuyang Y. , Leckie James O.
Published: September 2006

A systematic investigation of the relationship between chlorine exposure of a thin film composite crosslinked polyamide membrane (LE membrane, FilmTec©) and changes in membrane performance (water flux and salt rejection) is discussed here. Performance change of crosslinked polyamide membranes due to chlorination depended on pH and concentration of chlorine in the soaking bath. Membranes chlorinated at low pH and high chlorine concentration showed flux decreases at an early stage of filtration and then increases with filtration time. On the other hand, membranes chlorinated at high pH and low chlorine concentration showed flux increases at an early stage and then decreases with filtration time. Performance of chlorinated polyamide membranes was determined by the balance between rearrangement of polymer chains and the distortion of the chains due to chlorination. A conceptual model of performance change was proposed consistent with the chlorination of polyamide membranes. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5895–5902, 2006
Synthesis and properties of a poly(acrylic acid)/montmorillonite superabsorbent nanocomposite
Authors: Liu Ping‐Sheng , Li Li , Zhou Ning‐Lin , Zhang Jun , Wei Shao‐Hua , Shen Jian
Published: September 2006

A novel superabsorbent nanocomposite was synthesized through the intercalation polymerization of partially neutralized acrylic acid and a sodium‐type montmorillonite powder with N,N′‐methylenebisacrylamide as a crosslinker and ammonium persulfate and sodium sulfite as a type of mixed redox initiator. The effects of such factors as the amounts of the sodium‐type montmorillonite, crosslinker, and initiator and neutralization degree on the water absorbency of the nanocomposite were investigated. The structure and micrographs of the superabsorbent were characterized with Fourier transform infrared spectroscopy, X‐ray diffraction, and scanning electron microscopy. The results showed that the acrylic acid monomer was successfully intercalated into the montmorillonite layers and banded together with them. The montmorillonite layers were exfoliated and basically dispersed in the composite on a nanoscale after the polymerization. The water absorbency of the nanocomposite was much higher than that of pure poly(acrylic acid). The optimum absorbency of the nanocomposite in distilled water and saline water (NaCl concentration = 0.9%) was 1201 and 83 g/g, respectively. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5725–5730, 2006
New compounds for production of polyurethane foams
Authors: Paciorek‐Sadowska Joanna , Czupryński Bogusław
Published: September 2006

A method of boroorganic compound preparation with boric acid, 1,3‐propanediol, 2,3‐butanediol, and 1,4‐butanediol is described in this article. The obtained compounds were characterized with respect to their usability as polyol components for the production of polyurethane (PUR) foams. New boroorganic compounds were applied as polyol components for the foaming of rigid PUR–polyisocyanurate (PIR) foams. The method of preparation, foaming parameters, and physicochemical properties of the PUR–PIR foams and their results are presented. Application of the prepared borates as polyol components in the production of foams had a favorable effect on the properties of the foams. The obtained rigid foams were characterized by lower brittleness, higher compressive strength, content of closed cells, and considerably reduced flammability in comparison with standard foams. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5918–5926, 2006
EPDM rubber reclaim from devulcanized EPDM
Authors: Sutanto P. , Picchioni F. , Janssen L. P. B. M. , Dijkhuis K. A. J. , Dierkes W. K. , Noordermeer J. W. M.
Published: September 2006

Two types of ethylene–propylene–diene monomer (EPDM) rubbers, namely an efficient vulcanized (EV) and a semiefficient vulcanized (SEV), have been used to produce devulcanizates in a continuous setup. The devulcanizates are re‐cured using the same recipes as for the virgin rubber. The influence of mixing it with virgin rubber compound, the addition of extra sulfur, the operating devulcanization conditions, and the excess of devulcanizing agent on the mechanical properties (hardness, tensile strength, and compression set) of the reclaim rubbers are studied. Most of the reclaims produced show slightly inferior mechanical properties compared to the virgin rubber. Surface imperfection was observed on the devulcanizate with high devulcanizing agent content. Excellent mechanical properties (all above the standards) of the reclaim were found when the devulcanized profile material was used (EV‐EPDM) to replace the virgin one for application as a roofing sheet material (SEV‐EPDM). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5948–5957, 2006
Determination of swelling behavior and morphological properties of poly(acrylamide‐co‐itaconic acid) and poly(acrylic acid‐co‐itaconic acid) copolymeric hydrogels
Authors: Pulat Mehlika , Eksi Haslet
Published: September 2006

Poly(acrylamide‐co‐itaconic acid) (PAAmIA) and poly(acrylic acid‐co‐itaconic acid) (PAAIA) copolymeric hydrogels were prepared with different compositions via free‐radical polymerization. Ethylene glycol dimethacrylate (EGDMA) was used as an original crosslinker for these monomers. Gelation percentages of the monomers were studied in detail and it was found that addition of IA into the monomer mixture decreased the gelation percentage. The variation in swelling values (%) with time, temperature, and pH was determined for all hydrogels. PAA, which is the most swollen hydrogel, has the swelling percentage value of 2000% at pH = 7.4, 37°C. Swelling behaviors were explained with detailed SEM micrographs, which show the morphologic differences between dry and swollen hydrogels. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5994–5999, 2006
Fabrication of discontinuous fibers of poly (N‐vinylpyrrolidone) containing metalloporphyrin molecules
Authors: Jin Yuwei , Lu Xiaofeng , Wang Ce
Published: September 2006

This study described the preparation of discontinuous fibers of poly (N‐vinylpyrrolidone) (PVP) containing metalloporphyrin (Manganese (III) tetrakis (1‐methyl‐4‐pyridyl) porphyrin pentachloride) molecules using electrospinning method. SEM images showed that before adding the metalloporphyrin molecules, the electrospun nanofibers are straight and smooth, while after adding metalloporphyrin molecules into the PVP solutions, the SEM images clearly showed that there were two different types of fibers: the thinner fibrous phase and the thicker discontinuous fibers. The chemical composition of the resulting PVP/metalloporphyrin composite fibers was characterized by Fourier‐transform infrared (FTIR) and energy dispersive X‐ray (EDX) analysis. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 6017–6022, 2006
Stabilization of epidermal growth factor on thermal and proteolytic degradation by conjugating with low molecular weight chitosan
Authors: Chung Kyu Hwan , Park Se Hoon , Kim Mi Kyung , Park Hyung Dal , Son Tae Il
Published: September 2006

Epidermal growth factor (EGF, 5900 Da) has been reported to have the high efficiency of wound repair. However, the half‐life of EGF in the body is too short to exert the biological activity effectively when applied in free forms. Conjugation of the low molecular weight chitosan (LMC) to EGF was carried out to enhance its stability. EGF was conjugated with LMC activated by water‐soluble carbodiimide. The formation of EGF–LMC was quantitatively measured by indirect enzyme‐linked immunosorbent assay (ELISA). In a study of the thermal and the proteolytic stability of free EGF and EGF–LMC, EGF covalently attached to LMC was found to be more stable than free EGF in thermal and proteolytic stabilities. In animal experiments of which free EGF (control), EGF–LMC (test) and LMC (carrier) diluted in viscous carboxymethyl cellulose (CMC) solution (vesicle) were applied to the incisional wounds in rats, the EGF–LMC conjugates are considered to be potent wound healing agent with mitogenicity and wound‐healing property. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5072–5082, 2006
Discovery of Novel Aldose Reductase Inhibitors Characterized by an Alkoxy‐Substituted Phenylacetic Acid Core
Authors: Rakowitz Dietmar , Gmeiner Andreas , Matuszczak Barbara
Published: September 2006

In continuation of our effort aimed towards the development of novel aldose reductase inhibitors, several phenylacetic acids bearing an alkoxy substituent in position 3 or 4, respectively, were prepared and screened. The latter represent formal ring opening products of the cyclohexylmethyloxyphenylacetic acids IIa and IIb, recently elaborated in our group. Out of these series, compounds 4aa and 4ba characterized by an n‐heptyloxy subunit turned out to be the most potent inhibitors. Based on these unexpected results, we suggest that such an alkyl side chain acts as a useful surrogate for the 4‐bromo‐2‐fluorobenzyl residue often found in potent aldose reductase inhibitors.
Oral salmon calcitonin reduces Lequesne's algofunctional index scores and decreases urinary and serum levels of biomarkers of joint metabolism in knee osteoarthritis
Authors: Manicourt Daniel‐Henri , Azria Moïse , Mindeholm Linda , Thonar Eugene J.‐M. , Devogelaer Jean‐Pierre
Published: September 2006

Objective

To evaluate the effects of oral salmon calcitonin (sCT) on Lequesne's algofunctional index scores and on biomarkers of joint metabolism in knee osteoarthritis.

Methods

In this randomized, double‐blind trial, patients received either placebo (n = 18), 0.5 mg of sCT (n = 17), or 1 mg of sCT (n = 18) daily for 84 days. Biomarkers included C‐telopeptide of type II collagen (CTX‐II), type II collagen neoepitope C2C, collagenases (matrix metalloproteinase 1 [MMP‐1], MMP‐8, and MMP‐13), stromelysin (MMP‐3), tissue inhibitors of metalloproteinases 1 and 2, and hyaluronan. Statistical analysis included nonparametric tests.

Results

A total of 41 patients completed the study (13 in the group receiving 0.5 mg of sCT and 14 in each of the other 2 other groups). Although, on day 84, patients in both the placebo group and the group receiving 1 mg of sCT exhibited a similar significant decrease in pain scores, a significant reduction in the function score was observed only in the 2 sCT groups. On day 84, there was no significant decrease in biomarker levels in the placebo group, whereas significant reductions in the levels of both MMP‐3 and hyaluronan were observed in the 2 sCT groups. The group of patients receiving 1 mg of sCT exhibited significant decreases in the levels of CTX‐II, C2C, and MMP‐13.

Conclusion

By improving functional disability and by reducing levels of biomarkers that are thought to be predictive of joint space narrowing (and thus cartilage loss), oral sCT at a dose of 1 mg might be a useful pharmacologic agent in human knee OA.
In vitro and in vivo efficacy of a recombinant immunotoxin against folate receptor β on the activation and proliferation of rheumatoid arthritis synovial cells
Authors: Nagai Taku , Tanaka Masashi , Tsuneyoshi Yasuhiro , Matsushita Kakushi , Sunahara Nobuhiko , Matsuda Takemasa , Yoshida Hiroki , Komiya Setsuro , Onda Masanori , Matsuyama Takami
Published: September 2006

Objective

To investigate the effects of the recombinant immunotoxin dsFv anti‐FRβ‐PE38, which consists of the disulfide‐stabilized Fv fragment (dsFv) of the anti–folate receptor β (anti‐FRβ) antibody and the 38‐kd portion of Pseudomonas exotoxin A (PE38), on the activation and proliferation of cells that function in inflammatory and degradative processes in rheumatoid arthritis (RA) synovial tissue.

Methods

The Ig VH‐PE38 fusion protein and the Ig VL protein were produced in Escherichia coli, and then joined with a disulfide bond by engineering cysteine residues in the framework regions of these proteins. The effects of dsFv anti‐FRβ‐PE38 on the activation and proliferation of cells in RA synovial tissue were investigated by immunohistochemistry; the numbers of cells expressing CD68, vascular cell adhesion molecule 1, angiopoietin 1, CD34, proliferating cell nuclear antigen, and interleukin‐6 and the numbers of apoptotic cells were counted in RA synovial tissue engrafted into SCID mice treated or not treated with dsFv anti‐FRβ‐PE38. The effects of dsFv anti‐FRβ‐PE38 on the generation of osteoclasts from RA adherent synovial mononuclear cells in vitro was investigated by counting the number of resorption pits on dentin slices treated or not treated with dsFv anti‐FRβ‐PE38.

Results

Administration of dsFv anti‐FRβ‐PE38 reduced the numbers of macrophages, activated fibroblast‐like cells, endothelial cells, and proliferating cells and increased the numbers of apoptotic cells in RA synovial tissue engrafted into SCID mice. In vitro, the generation of osteoclasts from RA adherent synovial mononuclear cells was largely suppressed by treatment with dsFv anti‐FRβ‐PE38.

Conclusion

Our findings show that dsFv anti‐FRβ‐PE38 immunotoxin would be a promising tool for the treatment of RA synovitis, especially when administered intraarticularly.
Influence of male sex on disease phenotype in familial rheumatoid arthritis
Authors: Jawaheer Damini , Lum Raymond F. , Gregersen Peter K. , Criswell Lindsey A.
Published: September 2006

Objective

To examine sex differences in clinical, demographic, and genetic characteristics among a large cohort of patients with familial rheumatoid arthritis (RA).

Methods

We studied 1,004 affected members of 467 Caucasian multicase RA families recruited from the North American Rheumatoid Arthritis Consortium. Standardized information about demographic and clinical characteristics was collected from all patients. Affected individuals also underwent radiography of the hands and were genotyped for markers in the HLA region. Sex differences were assessed using contingency table analysis (for categorical variables) and Student's t‐tests for (continuous variables), and by multivariate logistic and linear regression analysis.

Results

Male patients had a significantly later onset of RA, were more likely to be seropositive for RF, and had significantly higher titers of anti–cyclic citrullinated peptide (anti‐CCP) antibodies compared with female patients, even after adjustment for covariates in multivariate analyses. Male patients were also significantly more likely to have a history of smoking and to be HLA–DRB1 shared epitope (SE) positive. Interestingly, female patients with an affected male sibling had significantly higher titers of anti‐CCP antibodies and were more likely to be SE positive compared with female patients without affected male siblings. Multivariate analyses indicated that the presence of the SE did not fully explain the increased anti‐CCP antibody titers observed in these families.

Conclusion

Sex has an important influence on the disease phenotype in RA, including the age at disease onset and autoantibody production. Furthermore, families with affected male members are characterized by higher titers of autoantibodies, particularly anti‐CCP antibodies. Our results indicate that these findings are not fully explained by differences in exposure to tobacco smoke, presence of the HLA–DRB1 SE, or other HLA region genetic variation. Thus, other genetic or nongenetic factors also contribute to sex differences in the RA phenotype.
Changes in Health Assessment Questionnaire disability scores over five years in patients with rheumatoid arthritis compared with the general population
Authors: Sokka Tuulikki , Kautiainen Hannu , Hannonen Pekka , Pincus Theodore
Published: September 2006

Objective

To analyze longitudinal data over 5 years for changes in Health Assessment Questionnaire (HAQ) scores in patients with rheumatoid arthritis (RA) and age‐ and sex‐matched controls from the general population.

Methods

In 2000 and 2005, identical self‐report questionnaires were mailed to a cohort of patients with RA and control cohort from the community. The questionnaire included the HAQ, which was used to assess functional status. Changes in HAQ scores over 5 years were analyzed.

Results

In 2000, 73% of 1,495 patients with RA and 77% of 2,000 general population controls responded to the questionnaire. In 2005, 84% of 2,022 patients with RA and 77% of 1,817 controls responded. A total of 863 patients with RA and 1,176 community controls responded in both 2000 and 2005 and were included in the analyses. Mean baseline HAQ scores were significantly higher in patients with RA than in controls (0.71 versus 0.17; P < 0.001). Over 5 years, the HAQ scores increased by 0.01 units per year in both the RA cohort and the community population; in both cohorts, the net change was primarily attributable to individuals over age 70 years. Changes in HAQ scores were similar in patients and controls who had low HAQ scores at baseline. Female patients with baseline HAQ scores of ≥0.5 had less potential for improvement than did controls. Among subjects in both groups who had HAQ scores >2, death was a common outcome over the next 5 years.

Conclusion

Currently, progression of functional disability among patients with RA and among persons in the general population is largely explained by the aging process. Our results showing stable function scores over 5 years in most patients with RA who are younger than age 70 years provide further evidence of improved status of RA patients today compared with the major declines observed in previous decades.
Regulation of Mcl‐1 expression in rheumatoid arthritis synovial macrophages
Authors: Liu Hongtao , Huang QiQuan , Shi Bo , Eksarko Polikseni , Temkin Vladislav , Pope Richard M.
Published: September 2006

Objective

Resistance to apoptosis may be an important mechanism contributing to the persistence of rheumatoid arthritis (RA). This study was undertaken to characterize the expression, regulation, and function of the antiapoptotic Bcl‐2 family member Mcl‐1 in macrophages isolated from the joints of patients with RA.

Methods

Mononuclear cells were isolated from the synovial fluid (SF) of patients with RA. Mcl‐1 expression was documented by intracellular staining of CD14+ cells using flow cytometry, and by real‐time polymerase chain reaction or immunoblot analysis of isolated macrophages. The expression of Mcl‐1 was suppressed with small interfering RNA (siRNA) or chemical inhibitors of the phosphatidylinositol 3‐kinase (PI 3‐kinase)/Akt‐1 and signal transducer and activator of transcription 3 (STAT‐3) pathways. Apoptosis was defined by the loss of mitochondrial transmembrane potential and by DNA fragmentation.

Results

The expression of Mcl‐1 was increased in CD14+ macrophages from the SF of patients with RA compared with normal in vitro–differentiated macrophages. Inhibition of the PI 3‐kinase/Akt‐1 or STAT‐3 pathways significantly reduced the percentage of CD14+ cells within the SF and resulted in the reduction of Mcl‐1 and the induction of apoptosis of synovial macrophages. Transfection of RA synovial macrophages with Mcl‐1 siRNA resulted in apoptotic cell death.

Conclusion

Mcl‐1 is critical for the survival of macrophages in the joints of patients with RA, and is therefore a potential therapeutic target in this disease.