bluuebunny/crossref_metadata_2025_split huggingface dataset:
Natural rubber composites reinforced with sisal/oil palm hybrid fibers: Tensile and cure characteristics
Authors: Jacob Maya , Thomas Sabu , Varughese K. T. 
Published: June 2004

AbstractNatural rubber was reinforced with untreated sisal and oil palm fibers chopped to different fiber lengths. The influence of fiber length on the mechanical properties of the hybrid composites was determined. Increasing the fiber length resulted in a decrease in the properties. The effects of concentration on the rubber composites reinforced with sisal/oil palm hybrid fibers were studied. Increasing the concentration of fibers resulted in a reduction in the tensile strength properties and tear strength but an increase in the modulus of the composites. Fiber breakage analysis was evaluated. The vulcanization parameters, processability characteristics, and stress–strain properties of these composites were analyzed. The extent of fiber alignment and the strength of the fiber–rubber interface adhesion were analyzed from the anisotropic swelling measurements. Scanning electron microscopy studies were performed to analyze the fiber/matrix interactions. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2305–2312, 2004
Properties of water‐blown rigid polyurethane foams with reactivity of raw materials
Authors: Seo W. J. , Park J. H. , Sung Y. T. , Hwang D. H. , Kim W. N. , Lee H. S. 
Published: June 2004

AbstractRigid polyurethane foams (PUFs) were prepared from polymeric 4,4‐diphenylmethane diisocyanate (PMDI; having functionality of 2.9), polyether polyols, silicone surfactant, amine catalysts, and distilled water. The effects of reactivity on the properties such as density, compressive and flexural strength, and glass‐transition temperature (Tg) of the PUF samples were studied. The kinetic rate of forming the PUF samples was increased with the catalyst and water content. With increasing OH value and functionality of the polyols, the density and compressive strength of the PUF samples also increased. For the PUF samples synthesized with polyols having high functionality (>5), the flexural strength of the PUF samples decreased with the functionality of the polyols. With increasing OH value and functionality of the polyols, the Tg of the PUF increased because of an increase in the degree of crosslinking of the PUF samples. The Tg value and compressive strength of the PUF samples were observed to increase with the NCO index. From this result, it was suggested that the increase in the Tg value and compressive strength of the PUF samples may be attributable to the additional crosslinks that arose from allophonate and biuret formation by the supplementary reactions of excess PMDI. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2334–2342, 2004
Kinetics of a thermooxidative degradation of polyethylene: Fractal analysis
Authors: Kozlov G. V. , Shustov G. B. , Zaikov G. E. 
Published: June 2004

AbstractIt is shown that kinetics of polyethylene thermooxidative degradation is influenced by both spatial and temporary (energetic) disorder of structure. Thus, the theorem of subordination is carried out (i.e., the multiplicative behavior of exponents describing these kinds of disorder is observed). As heat aging is usually carried out at rather high temperatures, this circumstance leads in an increase of contribution of temporary (energetic) disorder. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2348–2351, 2004
A scaling analysis of a friction processes of polyarylate
Authors: Kozlov G. V. , Burya A. I. , Zaikov G. E. 
Published: June 2004

AbstractThe obtained data infer the applicability and usefulness of the scaling approach and fractal analysis for the description of friction and wearing processes of polymers. The scaling nature of the relationships used for the description of the above‐mentioned processes is confirmed. Shown within the framework of the fractal analysis is the interdependence between the structure of polymer and parameters involved in these relationships, which were considered previously as empirical. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2352–2355, 2004
Ultrasonically irradiated emulsion copolymerization of styrene and surfmer
Authors: Zhang Jingzhi , Cao Ya 
Published: June 2004

AbstractThe nonionic surfmer AREO7 was first used in the ultrasonically irradiated emulsion polymerization of styrene. The added AREO7 could improve the emulsion solid content. Through FTIR, GC‐MS, and DSC studies, it was found that the polymer produced was the copolymer of styrene and AREO7. The copolymer latics polymerized in proper conditions displayed nanoparticles. When AREO7 concentration increased, there were more nanostructured copolymer gels, in which AREO7 molecules form an amphiphilic network, whereas polystyrene was located in hydrophobic droplet. The latics had a structured morphology that the AREO7 units were mainly on the surface of particles. The glass transition temperature (Tg) of copolymers decreased with the increase of AREO7 composition in copolymers. Freeze–thaw test showed that the freeze–thaw stability of the copolymer emulsion was improved greatly because of the increasing composition of AREO7 in copolymers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2356–2362, 2004
Morphologies and mechanical properties of polylactide blends with medium chain length poly(3‐hydroxyalkanoate) and chemically modified poly(3‐hydroxyalkanoate)
Authors: Takagi Yasuo , Yasuda Ryou , Yamaoka Michimasa , Yamane Tsuneo 
Published: June 2004

AbstractBlends of bacterial poly(3‐hydoroxyalkanoate) (PHA) with a medium‐length side chain and polylactide (PLA), and blends of the chemically modified PHA (ePHA) with PLA, were prepared. The morphologies, some physical properties, and thermal behavior of the blends based on PLA were investigated by electron microscopies, testing machines, and a differential scanning calorimeter, respectively. A blend of uncrystallized rubbery second components, PHA and ePHA, produced an increase in the impact toughness of the PLA blends in contrast to a decrease in the tensile strength value. PHA, especially, with an inserted epoxy group side chain was more effective in improving the morphology and the physical properties than PHA. The ePHA particles existed in the PLA domain as a dispersed phase having a size of 0.1–1 μm. The results of the biodegradation test demonstrated that the PLA blends still maintained their biodegradability and were more accessible to hydrolysis and microbial attack, resulting in a greater weight loss than the pure PLA. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2363–2369, 2004
Preparation of conductive polyaniline‐sulfonated EPDM ionomer composites from in situ emulsion polymerization and study of their properties
Authors: Xie Hong‐Quan , Pu Qing‐Lin , Xie Dong 
Published: June 2004

AbstractThe composites of polyaniline (PAn) and zinc sulfonated ethylene–propylene–diene rubber (EPDM) ionomer were made by polymerization of aniline in the presence of the ionomer by using a direct, one‐step in situ emulsion polymerization technique. The ionomers were prepared by sulfonation of EPDM rubber with acetyl sulfate in petroleum ether, followed by neutralization with zinc acetate solution. The ionomers with sulfonate contents of 10, 24, and 42 mmol SO3H/100 g were used for preparation of PAn/ionomer composites. The in situ polymerization of aniline was carried out in an emulsion comprising water and xylene containing the ionomer in the presence of dodecyl benzene sulfonic acid, acting as both a surfactant and a dopant for PAn. The composite was characterized by IR and WAXD. The composite obtained can be processed by melt method. The conductivity of the composite with lower sulfonate content was higher than that with higher sulfonate content. Conductivity of the composites exhibits a percolation threshold at about 13 wt % PAn. When the sulfonated content is 10 or 24 mmol SO3H/100 g and PAn content is 4–10 wt %, the composites behave as a thermoplastic elastomers with high ultimate elongation and low permanent set. The conductivity of the composite after secondary doping with m‐cresol is higher than the composite before secondary doping by about one order. Addition of zinc stearate as an ionic plasticizer lowers both the conductivity and the mechanical strength of the composites. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2211–2217, 2004
Adhesive properties of epoxy resin modified by end‐functionalized liquid polybutadiene
Authors: Barcia Fabio L. , Soares Bluma G. , Sampaio Eduardo 
Published: June 2004

AbstractAdhesive properties of epoxy resin networks modified with different functionalized liquid polybutadiene were evaluated by using aluminum adherent. The end‐functionalized polybutadiene rubbers were hydroxyl‐ (HTPB), carboxyl‐ (CTPB), and isocyanate‐terminated polybutadiene (NCOTPB). The adhesive properties depend upon the morphology and the degree of interaction between the rubber–epoxy system. The most effective adhesive for Al–Al joint in both butt and single‐lap shear testing was epoxy resin–NCOTPB system. This system presents stronger rubber–epoxy interactions and a higher degree of rubber particle dispersion with particle size diameter in the nanoscale range. These characteristics were not important for improving the toughness of the bulk network but are fundamental for the improvement of adhesive strength. The effect of the pretreatment of the aluminum surface on the roughness was also evaluated by using profilometry analysis. The type of failure was also investigated by analyzing the adhered surfaces after fracture by scanning electron microscopy and profilometry. A proportion of cohesion failure higher than 90% was observed in all systems. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2370–2378, 2004
Polymeric proton conducting systems based on commercial elastomers. II. Synthesis and microstructural characterization of films based on HSBR/EPDM/PP/PS/silica
Authors: Escribano P. G. , Nacher A. , Del Rio C. , González L. , Acosta J. L. 
Published: June 2004

AbstractThis article reports on the synthesis and structural characterization of films containing hydrogenated poly(butadiene‐styrene) block copolymer/ethylene‐propylene terpolymer/polypropylene, hydrogenated poly(butadiene‐styrene) block copolymer/ethylene‐propylene terpolymer/polystyrene, and hydrogenated poly(butadiene‐styrene block copolymer/ethylene‐propylene terpolymer/silica) crosslinked with peroxides and heterogeneously sulfonated. Sulfonation of the different polymeric systems gives rise to materials with high proton conductivity and great dimensional stability, suited for application in a variety of electronic devices. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2394–2402, 2004
Effect of the monomer ratio on the properties of poly(methyl methacrylate butyl acrylate) latex‐modified mortars
Authors: Pei Meishan , Wu Yue , Kim Wanki , Hyung Wongil , Soh Yangseob 
Published: June 2004

AbstractThis article deals with the effect of the monomer ratio on the typical properties of polymer‐modified mortars with poly(methyl methacrylate butyl acrylate) latices. Polymer‐modified mortars, with methyl methacrylate/butyl acrylate copolymer latices of various methyl methacrylate/butyl acrylate ratios, were prepared with different polymer/cement ratios and were tested for their workability, air content, compressive strength, flexural strength, and water absorption. On the basis of the test results, the effects of the monomer ratio and polymer/cement ratio on the typical properties were examined. The properties of the latex‐modified mortars were affected to a great extent by both the monomer ratio and polymer/cement ratio. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2403–2409, 2004
Improved mechanical properties of shape‐memory polyurethane block copolymers through the control of the soft‐segment arrangement
Authors: Cho Jae Whan , Jung Yong Chae , Chung Yong‐Chan , Chun Byoung Chul 
Published: June 2004

AbstractHigh‐performance shape‐memory polyurethane block copolymers, prepared with two types of poly(tetramethylene glycol) (PTMG) used as soft segments, were investigated for their mechanical properties. Copolymers with a random or block soft‐segment arrangement had higher stresses at break and elongations at break than those with only one kind of PTMG. Random copolymers with fewer interchain interactions showed higher elongation than block copolymers. All the copolymers had shape‐recovery ratios higher than 80%. In dynamic mechanical testing, the glass‐transition behavior clearly depended on the soft‐segment arrangement: random copolymers had only one glass‐transition peak, whereas block copolymers showed two separate glass‐transition peaks. Overall, the control of the soft‐segment arrangement plays a vital role in the development of high‐performance shape‐memory polyurethane. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2410–2415, 2004
Synthesis of dextran dicarboxylic acid and investigation of its complexes with metal ions in aqueous solutions
Authors: Şenöz Hülya , Güner Alı , Tunoğlu Nazan 
Published: June 2004

AbstractDextran dicarboxylic acid was successfully synthesized by the direct oxidation of dextran with sodium chlorite and its characterization was realized by means of IR and NMR spectrometers. Viscometric measurements were done by metal–polymer complexes with Cu(II), Ni(II), and Cd(II) in aqueous solution at 25°C and Ni(II) was found to be the most effective ion in decreasing the viscosity of the polymer solution than the other two metal ions, whereas Cd(II) was the least effective cation. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2262–2265, 2004
Preparation and characterization of SMA(SAN)/silica hybrids derived from water glass
Authors: Shen Liang , Zhong Wei , Wang Haitao , Du Qiangguo , Yang Yuliang 
Published: June 2004

AbstractPoly(styrene‐co‐maleic anhydride) (SMA)/silica and poly(styrene‐co‐acrylonitrile) (SAN)/silica hybrids were prepared via a sol‐gel route by using silicic acid oligomer (SAO) from water glass in this article. This convenient route is different from the traditional one from tetraethoxysilane (TEOS). The polycondensation behavior of the SAO and the aggregation behavior of the silica particles in the hybrids were investigated. The prepared SMA(SAN)/silica hybrids were characterized by infrared spectroscopy, dynamic light scattering, thermogravimetric analysis, differential scanning calorimetry, and scanning electron microscopy. The results showed that the particle size of silica in hybrids increased with increasing silica loading and decreased dramatically by adding the coupling agents. The decomposition temperature and the glass‐transition temperature of the hybrids were higher than the precursory polymers. The mechanical properties of blends of acrylonitrile‐butadiene‐styrene copolymers (ABS) resin with the hybrids were also tested and the results indicated that the well‐dispersed silica particles in the hybrids indeed reinforced the blends. Some nanocomposites based on ABS were prepared in this way. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2289–2296, 2004
Bone cell viability on collagen immobilized poly(3‐hydroxybutrate‐co‐3‐hydroxyvalerate) membrane: Effect of surface chemistry
Authors: Tesema Y. , Raghavan D. , Stubbs J. 
Published: June 2004

AbstractThe effect of surface chemistry on proliferation and morphology of bone cells cultured on surface modified poly(3‐hydroxybutrate‐co‐3‐hydroxyvalerate) (PHBV) and untreated PHBV was evaluated. The surface of cast PHBV film was physically and chemically immobilized with collagen. For preparing chemically immobilized collagen surface, PHBV film was ozone treated followed by grafting of PMAA chains and the immobilization of collagen. The surface roughness and hydrophilicity of PHBV film were determined by atomic force microscopy (AFM) and contact angle measurements, respectively. It was found that the duration of ozone exposure and monomer concentration used for grafting PMMA chains influenced the amount of collagen immobilized. The cell proliferation on PHBV surfaces with chemically and physically immobilized collagen was compared with untreated PHBV using 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl tetrazolium bromide (MTT) assay. The bone cell activity on chemically and physically immobilized collagen PHBV films was found to be 246 and 107% for UMR‐106 and 68 and 9% for MC3T3 cell lines, respectively. Although the results are very preliminary, the chemically grafted collagen on PHBV surface provided a favorable matrix for cell proliferation. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2445–2453, 2004
Method for induction time determination using data obtained from isothermal crystallization experiment monitored by DSC
Authors: Šipušić J. , Kurajica S. , Bezjak A. 
Published: June 2004

AbstractPreviously introduced method for transforming kinetic function expression was applied on the differential form of isothermal Johnson–Mehl–Avrami (JMA) nucleation and growth equation, to determine the duration of the induction period, τ. The assisting function φ = tm was used to obtain a new equation, which enables determination of the induction time, τ, along with the Avrami parameter, n. The procedure was tested using a developed computer program on simulated data, experimental poly(ethylene‐terephtalate) (PET) cold crystallization data, and poly(ester‐urethane) polycaprolactone‐diol polymer (PEU) crystallization data obtained from literature. The test results show the validity of developed equations and their applicability for the determination of kinetic parameters, particularly the induction time. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2454–2458, 2004
Filamentous green algae additions to isocyanate based foams
Authors: Johnson M. , Shivkumar S. 
Published: June 2004

AbstractFilamentous green algae, Cladophora glomerata, obtained from rivers and streams in California was used as a filler in isocyanate‐based foams. Up to 40 wt % dried and chopped algal fibers were added to the isocyanate–polyol mix. The algal fibers and foam samples were examined by scanning electron microscopy. The effective hydroxyl number of the algae and the tensile and compressive properties of the composite foam were measured. The results indicate that foams with a uniform cell size were obtained for algal fiber lengths between 500 and 600 μm. Peak mechanical properties were obtained for algae concentrations between 5 and 10 wt %. The elastic modulus of the foam follows a power law relationship with density, with an exponent of 1.6. The overall hydroxyl number for the algae is around 300. The hydroxyl groups in the algae can serve as efficient sites for reactions with isocyanate and hence algae fibers can act as reinforcing fillers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2469–2477, 2004
Mechanical properties of biorenewable fiber/plastic composites
Authors: Julson James L. , Subbarao Gurram , Stokke D. D. , Gieselman Heath H. , Muthukumarappan K. 
Published: June 2004

AbstractPlastic fiber composites, consisting of polypropylene (PP) or polyethylene (PE), and pinewood, big blue stem (BBS), soybean hulls, or distillers dried grain and solubles (DDGS), were prepared by extrusion. Young's modulus, tensile and flexural strengths, melt flow, shrinkage, and impact energy, with respect to the type, amount, and size of fiber on composites, were evaluated. Young's moduli under tensile load of wood, BBS, and soybean‐hull fiber composites, compared with those of pure plastic controls, were either comparable or higher. Tensile strength significantly decreased for all the PP/fiber composites when compared with that of the control. Strength of BBS fiber composites was higher than or comparable to that of wood. When natural fibers were added there was a significant decrease in the melt flow index for both plastic/fiber composites. There was no significant difference in the shrinkage of all fiber/plastic composites compared to that of controls. BBS/PE plastic composites resulted in higher notched impact strength than that of wood or soybean‐hull fiber composites. There was significant reduction in the unnotched impact strength compared to that of controls. BBS has the potential to be used as reinforcing materials for low‐cost composites. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2484–2493, 2004
Porous magnetic chelator support for albumin adsorption by immobilized metal affinity separation
Authors: Odabašı Mehmet , Uzun Lokman , Denizli Adil 
Published: June 2004

AbstractMagnetic poly(2‐hydroxyethylmethacrylate) (mPHEMA) beads are modified by iminodiacetic acid (IDA) to implify the reactive groups and subsequent binding of Cu2+ ions to form metal chelate. mPHEMA beads, in the size range of 80–120 μm, were produced by a modified suspension polymerization technique. mPHEMA beads were characterized by swelling tests, electron spin resonance (ESR), FTIR, and scanning electron microscopy (SEM). Important results obtained in this study are as follows. The swelling ratio of mPHEMA beads was 34%. The presence of magnetite particles in the polymeric structure was confirmed by ESR. FTIR data confirmed that the magnetic polymer beads were modified with functional groups IDA. The mPHEMA beads have a spherical shape and porous structure. The effect of pH and concentration of human serum albumin (HSA), on the adsorption of HSA to the metal‐chelated magnetic beads, were examined in a batch reactor. Most importantly, the magnetic beads had little nonspecific adsorption for HSA (0.5 mg/g) before introducing IDA groups. Cu2+ chelation increased the HSA adsorption up to 28.4 mg/g. Adsorption behavior can be described at least approximately with the Langmuir equation. Regeneration of the metal‐chelated magnetic beads was easily performed with 1.0M NaSCN, pH 8.0, followed by washing with distilled water and reloading with Cu2+. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2501–2510, 2004
Selecting areas to protect the biodiversity of aquatic ecosystems in a semiarid Mediterranean region using water beetles
Authors: Sánchez‐Fernández D. , Abellán P. , Velasco J. , Millán A. 
Published: June 2004

Abstract
In this work, carried out in the province of Murcia, a representative semi‐arid area of the Iberian Peninsula, water beetles were used as indicators to identify the aquatic ecosystems with the highest interest for conservation. For that purpose, an iterative algorithm of complementarity based on the richness of aquatic Coleoptera was applied. ‘Complementarity’ refers to the degree to which an area, or set of areas, contributes otherwise unrepresented attributes to a set of areas. This principle was used to maximize the number of species represented within a given number of areas.
Only the species subsets whose taxonomic status, presence and distribution in the study area are well known were used. In total, 146 species were included, of which 12 are Iberian endemics and 32 are rare species (found only in one grid cell in the study area).
The highest correlation was generally shown by species richness with endemic, rare and vulnerable species richness. Thus, basing conservation strategies on species richness appears to be an effective protocol.
To preserve the highest degree of biodiversity in the aquatic ecosystems of the study area, the following need to be protected: (a) headwater streams in the north west of the province; (b) the uppermost reaches of the Segura River; (c) hypersaline and coastal ramblas; (d) rock pools and coastal ponds.
The present network of Protected Natural Spaces in the study area does not include many of the aquatic ecosystems shown to have the highest biodiversity of beetles. However, the future European ‘Natura 2000’ network will protect the 10 grid cells of highest aquatic biodiverstity, or at least part of them.
Copyright © 2004 John Wiley & Sons, Ltd.