bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ring‐Closing Metathesis as a Basis for the Construction of Aromatic Compounds
Authors: Donohoe Timothy J. , Orr Allan J. , Bingham Matilda 
Published: March 2006

AbstractThe use of metathesis, especially in the context of ring‐closing metathesis (RCM) to form five‐ and six‐membered rings, is widespread in organic chemistry today. However, there are surprisingly few examples of the reaction being used to form aromatic compounds. The central place of aromatic compounds in both medicinal chemistry and natural products synthesis, coupled with the efficiency and functional group tolerance of RCM catalysts, means that there is now an interesting opportunity to use RCM for the synthesis of arenes. Although the formation of an aromatic compound was viewed in many early examples as an undesirable degradation product, several rationally designed methods towards the preparation of aromatic compounds by RCM have recently been developed.
Synthesis, characterization, and antitumor activity of poly(maleic anhydride‐co‐vinyl acetate‐co‐acrylic acid)
Authors: Can Hatice Kaplan , Doğan A. Lale , Rzaev Zakir M. O. , Uner Ayşegül Hasegeli , Güner Ali 
Published: March 2006

AbstractThe ternary copolymerization of maleic anhydride (MA), vinyl acetate (VA), and acrylic acid (AA) [P(MA‐co‐VA‐co‐AA)], which is considered to be an acceptor–donor–acceptor system, was carried out in 1,4‐dioxane with benzoyl peroxide as an initiator at 70°C under a nitrogen atmosphere. Constants of complex formation for the monomer systems in the study were determined by UV–visible (hydrogen‐bonding complex) and 1H‐NMR (charge transfer complex) methods, respectively. The results show that polymerization of the P(MA‐co‐VA‐co‐AA) system proceeds by an alternating terpolymerization mechanism. It is shown that the synthesized copolymers have typical polyelectrolyte behavior, ability for reversible hydrolysis–anhydrization reactions, and semicrystalline structures. In these cases, including radical polymerization, and formation of semicrystalline structures, the hydrogen‐bonding effect plays a significant role. The in vitro cytotoxicities of the synthesized terpolymer and alternating copolymer were evaluated using Raji cells (human Burkitt lymphoma cell line). The antitumor activities of prepared anion‐active copolymers were studied using methyl–thiazol–tetrazolium colorimetric assay and 50% of the cytotoxic dose of each copolymer and terpolymer were calculated. Hydrolyzed P(MA‐co‐VA‐co‐AA) and P(MA‐alt‐AA) copolymers have sufficiently high antitumor activity, which depends on the amount of hydrogen‐bonding carboxylic groups and their regular distribution in the side chain of functional macromolecules. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3425–3432, 2006
Preparation and characterization of ceria nanoparticles supported on poly(4‐vinyl pyridine‐co‐divinyl benzene)
Authors: Samba Sivudu K. , Shailaja D. 
Published: March 2006

AbstractFormation of ceria nanoparticles in 2% divinyl benzene (dvb) crosslinked 4‐vinyl pyridine (4vp) polymer [poly(4vp‐co‐dvb)] microspheres was investigated. The polymer was prepared by free radical suspension polymerization method. Poly(4vp‐co‐dvb)/ceria nanocomposites were prepared by reacting CeCl3·7H2O and NaOH in the presence of poly(4vp‐co‐dvb) at room temperature in aqueous media. The mole ratio of the metal to polymer was varied from 2.5 to 10% with an increment of 2.5. The polymer and nanocomposities were characterized by various spectrochemical methods. The coordination of nitrogen atoms of the polymer with Ce(IV) of ceria (CeO2) has been confirmed from X‐ray photoelectron spectroscopy (XPS). The method has yielded ceria nanoparticles in an average size of 15 nm according to transmission electron microscopy. Differential scanning calorimetry, thermogravimetric analysis, X‐ray diffractometry and XPS analysis with respect to mole percentage of ceria in the composite are discussed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3439–3445, 2006
Calorimetric studies of PP/Mater‐Bi blends aged in soil
Authors: Cadenato Ana , Ramis Xavier , Salla Josep Ma , Morancho Josep Ma , Contat‐Rodrigo L. , Vallés‐Lluch A. , Ribes‐Greus A. 
Published: March 2006

AbstractBlends of polypropylene and a commercial biodegradable additive (Mater‐Bi AF05H) were subjected to a soil burial test for 1 year. The effect of the degradation process on the morphology of the blend was studied by differential scanning calorimetry. The melting and crystallization temperatures, degree of crystallinity, lamellar thickness distribution, and crystallization kinetics were analyzed for both the nondegraded and degraded blends and for the pure components before blending and degradation. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3446–3453, 2006
Evolutions of microstructure and dielectric behavior of epoxy based insulator‐insulator composites over long periods of time
Authors: Vouyovitch L. , Flandin L. , Bessede J.‐L. , Alberola N. D. 
Published: March 2006

AbstractAging of epoxy based composites used as insulators in the industry are investigated. The analysis of a composite aged for 20 years in actual service conditions points out chemical degradations, a structural recovery, a tendency for particle debonding from the polymer matrix and with respect to the unaged sample, and no significant changes in the permittivity values measured at 50°C. To understand this latter result, a purely physical aging was carried out on fresh composites with similar formulation as the insulator aged 20 years in service. A detailed analysis of the changes in properties during physical aging is proposed. It is concluded that the constant ε′ value at 50°C found for the 20 years aged composite results from two opposite phenomena: an increase in the relative dipole amount due to structural recovery and/or the presence of polar species at the polymer/filler interface that both increase ε′ and the loss of polar species in the bulk that decreases the ε′. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3454–3464, 2006
The effect of shear forces on the microstructure and mechanical properties of epoxy–clay nanocomposites
Authors: Oh Tak‐keun , Hassan Mervat , Beatty Charles , El‐Shall Hassan 
Published: March 2006

AbstractThe objective of this work is to understand the effect of shear force on the properties of epoxy–clay nanocomposites. The shear force was controlled by changing the revolutions per minute on a mechanical mixer. Differences in the aspect ratio of clay layers and differences of clay particle distribution in the epoxy matrix were caused by shear force. Shear force mechanism on epoxy–clay nanocomposites' intercalation/exfoliation were compared with the other mechanism already suggested. X‐ray diffraction, transmission electron microscopy, and scanning electron microscopy were utilized to investigate the degree of exfoliation and morphology. The mechanical and thermal properties were also studied to demonstrate the effect of shear force. This study revealed that appropriate shear force and mixing time on nanocomposite preparation was required to achieve the desired properties. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3465–3473, 2006
Interactions of active carbon with low‐ and high‐molecular weight polyethylene glycol and polyethylene oxide
Authors: Bar‐Chaput Sandrine , Carrot Christian 
Published: March 2006

AbstractComposites of active carbon in a polymeric matrix composed of polyethylene oxide (PEO) and polyethylene glycol (PEG) having different molecular weight distributions were obtained by melt mixing. Characterization of the amount of bound polymer in the whole range of composition for the polymeric matrix has been performed after dissolution of the matrix in water. Size exclusion chromatography of the solution has been used to determine the composition of the polymeric bound layer. It has been shown that in these conditions of mixing, the amount of bound polymer slightly decreases from a pure PEG to a pure PEO matrix. Furthermore, PEO is preferentially bound to the active carbon. A simple model is used to show that bonding occurs preferentially by monomeric units rather than by chain ends. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3490–3497, 2006
Synchronous toughening and reinforcing of polypropylene with ultrahigh‐molecular‐weight polyethylene via melt blending: Mechanical properties, morphology, and rheology
Authors: Wang Xiaodong , Li Hangquan , Jin Riguang 
Published: March 2006

AbstractBlending systems based on polypropylene (PP) and ultrahigh‐molecular‐weight polyethylene (UHMWPE) were prepared via a melt extrusion by the four‐screw and the twin‐screw extruders, respectively. The mechanical evaluation demonstrated that the synchronous toughening and reinforcing effects could be achieved from the combination of the PP and the UHMWPE, in which the toughness and the tensile properties could be improved with increasing the UHMWPE content, and achieved optimal values at a weight ratio of PP/UHMWPE (85/15). EPDM can be used as a compatibilizer to improve the compatibility and the interfacial adhesion between the PP and the UHMWPE. This resulted in more effective toughening and reinforcing effects. In contrast, for the PP/UHMWPE blends prepared by the normal twin‐screw extruder, the poor dispersion capacity for the UHMWPE resulted in a deterioration of all mechanical parameters. Morphological observation revealed that the UHMWPE domain was well distributed as tiny particles in the PP matrix, which was confirmed by the differential scanning calorimetry analysis. The toughening effect was attributed to the energy dissipation caused by these rigid tiny particles that detached from the matrix to initiate the local matrix shear yield and formed the void. Rheological investigation demonstrated that there was an interesting composition dependence of viscosity, for which the melt viscosities of the PP/UHMWPE blends decreased when 5 wt % UHMWPE was added, and then began to increase as the UHMWPE content continued to increase. However, this dependence on composition became weaker because of the compatibilization of the EPDM. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3498–3509, 2006
Surface modification on nanoscale titanium dioxide by radiation: Preparation and characterization
Authors: Jiang Bo , Zu Xiaotao , Tang Fangyuan , Wu Zhihong , Lu Jian , Wei Qingrong , Zhang Xingdong 
Published: March 2006

AbstractElectron beam mutual radiation to induce graft polymerization has been carried out respectively, between nanoscale anatase‐ or rutile‐titanium dioxide particles surface and methyl methacrylate (MMA). The composition and properties of surface modified titanium dioxide were investigated by a number of surface sensitive techniques: X‐ray photoelectron spectrum (XPS), FTIR, X‐ray diffraction (XRD), and NMR. Results of the technological measurements show how surface chemistry is affected throughout the surface modification process, finally leading to a complete and homogeneous vinyl compound overlayer on top of the titanium dioxide samples. In comparison with stereochemical structures of the graft molecular chains and the PMMA induced by radiation polymerization, the surfaces of the oxides are considered to provide a template for the graft polymerization. The grafted titanium dioxide is found to produce a stable colloidal dispersion, in good solvents for the grafted polymer, and the dispersibility of grafted dioxides is influenced by temperature. In addition, the wettability of the surface of titanium dioxide to water is readily controlled by grafting of hydrophilic or hydrophobic polymers. Based on the above results, it is concluded that MMA is covalently linked to the surface of titanium dioxide by a surface modification process. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci, 100: 3510–3518, 2006
Microstructural and mold resistant properties of environment‐friendly oil‐modified polyurethane based wood‐finish products containing polymerized whey proteins
Authors: Wright Nareen C. , Li Jiancai , Guo Mingruo 
Published: March 2006

AbstractEnvironmental concerns associated with the level of volatile organic compounds used in surface coatings have stimulated increased scientific research toward novel methods of developing environment‐friendly coatings. Prototype wood finish products containing polymerized whey proteins (PWP) were formulated. The microstructural characteristics of dry films prepared from environment‐friendly wood finishes containing PWP were examined using atomic force microscopy (AFM) and confocal laser scanning microscopy (CLSM). The susceptibility of the coatings to microbial degradation was also examined using an accelerated mold test. AFM analysis revealed that increased addition of PWP resulted in films with increased surface roughness, decreased number of voids, and increased void size due to excessive aggregation among polymer components. CLSM analysis showed that the PWP distribution in the films is enhanced by homogenization of the coating mixes. There was no significant increase (P > 0.05) in mold growth between panels coated with finish containing PWP and those without PWP. Test panels coated with formulation containing PWP and low levels of biocide (0.3%) resulted in a significant decrease in mold growth in comparison to commercially available water‐based polyurethane coatings (P < 0.05). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3519–3530, 2006
The influence of alkali pretreatments in lyocell resin finishing—Resin distribution and mechanical properties
Authors: Manian Avinash P. , Rous Mohammad Abu , Schuster K. Christian , Bechtold Thomas 
Published: March 2006

AbstractLyocell fabric samples were pretreated with NaOH and KOH and resin finished. The treated samples were tested to determine the influence of alkali pretreatments on the tenacity, abrasion resistance, and crease recovery of resin‐finished lyocell. Alkali pretreatments resulted in a higher surface concentration of the crosslinking reagent in fabrics, leading to lowered crease recovery and abrasion resistance. The pretreatments also exerted a deleterious influence on the tensile strength in resin‐finished samples. However, the differential distribution of crosslinking reagent within the textile structure does not appear to be the only factor responsible for the changes observed in substrate properties; other factors also appear to be responsible for the results observed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3596–3601, 2006
Synthesis and characterization of p‐perfluoro{1‐[2‐(2‐fluorosulfonyl‐ethoxy)propoxy]}ethylated poly(α‐methyl styrene)
Authors: Ni Hong‐Bo , Yang Ji‐Cheng , Zhao Cheng‐Xue 
Published: March 2006

Abstractp‐Perfluoro{1‐[2‐(2‐fluorosulfonyl‐ethoxy)propoxy]}ethylated poly(α‐ methyl styrene) 3 was synthesized via electron transfer of perfluoro‐di{2‐[2‐(2‐fluorosulfonyl‐ethoxy)propoxy]}propionyl peroxide 2 and poly(α‐methyl styrene) 1 at different reactant molar ratios (2 : 1). The modified polymer 3 was characterized by various techniques. The ring p‐substitution was proved by FTIR and 19FNMR. The desulfonation appeared at above 124°C was found by TGA. The molecular weight determined by GPC increased with the increase of reactant molar ratio, and the polydispersity values indicated there was no degradation of the parent polymer chain in the reaction. Followed by hydrolysis and acidification, the modified polymer 3 could be further quantitatively converted into its sulfonic form 4. Ion exchange capacity of novel polyelectrolyte 4 can be controlled by changing reactant molar ratio (2 : 1). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3615–3618, 2006
Proton conducting blends based on polysulfones and elastomers
Authors: Linares A. , Acosta J. L. , Rodríguez S. 
Published: March 2006

AbstractWith the aim of improving the performance of conventional proton conducting membranes, systems based on two poly(arylene ether sulfone)s and two elastomers were obtained by heterogeneous sulfonation with chlorosulfonic acid. Subsequently, they were characterized, morphologically and electrically, by techniques such as infrared spectroscopy (FTIR), differential scanning calorimetry, dynamic‐mechanical analysis, and complex impedance spectroscopy. From the results, it was verified that the reaction of sulfonation had taken place, as well as that these materials formed incompatible and good proton conducting blends. In addition, the storage modulus and the conductivity were subjected to a statistical design to predict the optimum composition, presenting the best mechanical and conducting proton values and as a consequence the most suitable membrane from the point of view of its application in the field of the fuel cells. Very promising results have been found especially with membranes based on binary blends constituted by thermoplastic/elastomer polymers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3474–3482, 2006
Novel nitrogen‐containing epoxy resin. II. Cure kinetics by differential scanning calorimetry
Authors: Hong Zhang Xing , Qin Min Yu , Zhao Hui , Mei Wan Hong , Rong Qi Guo 
Published: March 2006

AbstractThe isothermal and nonisothermal cure behaviors of a novel nitrogen‐containing epoxy resin (XT resin) were studied by differential scanning calorimetry (DSC). Various kinetic parameters and details of cure process were obtained based on the Avrami theory. The results indicated that Avrami method is suitable for calculating the kinetic parameters up to the gel point at least. The apparent activation energy (Ea) for isothermal cure process was in agreement with that for nonisothermal cure process. Ea value in the early stage (78.5–81.0 KJ mol−1) was about three times than that in the later stage (23.3–26.5 KJ mol−1). The kinetic results from Avrami theory may present a combined effect of all factors, and which is helpful to understand the cure technique for XT–DDS system. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3483–3489, 2006
Effect of water absorption, freezing and thawing, and photo‐aging on flexural properties of extruded HDPE/rice husk composites
Authors: Panthapulakkal S. , Law S. , Sain M. 
Published: March 2006

AbstractDurability of lingo‐cellulosic fiber composites under environmental conditions such as moisture, freezing and thawing, and UV exposure needs to be determined prior to the use of these composite materials in outdoor applications. Dimensional stability and changes in the flexural strength and stiffness of extruded rice husk filled high‐density polyethylene composites with and without processing additives such as compatibilizers and processing aid were examined after exposing the composites to water, conditions of freeze–thaw cycles, and UV light. Water absorption results indicated a decrease in the rate of penetration of water in the composites in the presence of compatibilizers. The reduction in strength and stiffness after water absorption was lower for composites with compatibilizers than for the composites without any additives. Freezing and thawing experiments also showed the dimensional changes and degradation of strength and stiffness were less in composites with compatibilizers. Presence of processing aid in the composite showed a similar or enhanced water absorption and loss of mechanical properties, compared with those of the composite without processing additives. Although the composites showed a discoloration of the surface after the UV exposure time (745 h) studied, it was found that within this period of UV exposure the flexural strength and stiffness of the composites did not show significant change. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3619–3625, 2006
Electrochemistry of methanofullerene films: Simultaneous cyclic voltammetry and electrochemical quartz crystal microbalance studies
Authors: Zhang H. , Huang X. , Fan L. Z. , Nin B. , Wu Y. Q. , Zheng L. P. , Cao Y. 
Published: March 2006

AbstractElectrochemical properties of eight methanofullerene films, prepared on electrodes by casting, were examined by means of cyclic voltammetry and electrochemical quartz crystal microbalance (EQCM) technique in acetonitrile solution. Compared with C60 film, the film stability with respect to dissolution is associated with the length of the alkyl chains introduced into C60 cage and is strongly dependent on the nature of the cation of the supporting electrolyte. TBA+, Li+, K+, and Na+ were selected to observe the effect of countercations on the electrochemical behavior of methanofullerene films. In TBAPF6 solution, when short chains, such as formic ether or butyl butyrate groups, were introduced into C60 cage, the film stability was less than that of C60. When the length of the alkyl chain was extended to butyl 12 alkanoate group, the film would not dissolve until the third reduction process because the long alkyl chain could inflect and encase the cations into the film. In KPF6 or NaClO4 solution, however, the solubility of the salt formed by K+ or Na+ with methanofullerene anion was higher than that formed by TBA+ with methanofullerene anion. Li+ (alkali metal) affected the behavior of the films in different ways. The possible electron‐transfer mechanisms of methanofullerene films in various supporting electrolyte solutions were presented. Furthermore, the film images observed by atomic force microscopy indicated that TBA+ and Li+ affected the behavior of the methanofullerene films in different ways. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3634–3640, 2006
Effect of modified carbon black on the filler–elastomer interaction and dynamic mechanical properties of SBR vulcanizates
Authors: Han Jingjie , Zhang Xiliang , Guo Weihong , Wu Chifei 
Published: March 2006

AbstractA new modified carbon black (GCB) was prepared by adding special RFL latex into N220. Dynamic properties were obtained over a wide range of temperatures and strains on vulcanizates filled with GCB and unmodified carbon black, respectively. The results show that the GCB can effectively decrease the tan δ value at 60 and 90°C of SBR vulcanizates compared with that of the common unmodified carbon blacks, which responds to the fact that GCB is beneficial to lower rolling resistance and heat generation of the vulcanizates in comparison to that of the unmodified carbon black. Among the factors responsible for this, filler networking and filler–elastomer interaction play a dominant role. The effects of filler loading on mechanical properties of vulcanizates were also investigated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3707–3712, 2006
Multicarboxylic aromatic acid core initiator for the synthesis of star‐shaped poly(ϵ‐caprolactone) with carboxyl end groups
Authors: Jia Zhongfan , Huang Junlian 
Published: March 2006

AbstractWe successfully carried out the ring‐opening polymerization of ϵ‐caprolactone with 1,3,5‐benzenetricarboxylic acid and 1,2,4,5‐benzenetetracarboxylic acid as the core initiators at 225°C in bulk, and three‐armed and four‐armed star poly(ϵ‐caprolactone)s [poly(ϵ‐CL)s] with carboxyl end groups were obtained. No transesterification, which would have led to a decrease in the molecular weight of poly(ϵ‐CL), was found. The effects of the polymerization conditions on the polymerization are discussed; the poly(ϵ‐CL)s were characterized by1H‐NMR, gel permeation chromatography, and thermogravimetric analysis in detail. A mechanism of alkyl–oxygen bond scission by the nucleophilic attack of the carboxyl anions via hydrogen proton transfer is presented for this system. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3713–3717, 2006