bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamic sorption and transport of water vapor in dense polyimide membranes
Authors: Zeng Chuyi , Li Jiding , Chen Tianquan , Chen Jian , Chen Cuixian 
Published: August 2006

AbstractSeries of polyimide membranes were synthesized using varied monomers such as pyromellitic dianhydride, 3,3′4,4′‐benzophenonetetracarboxylic dianhydride, 4,4′‐diaminodiphenylether, 4,4′‐diaminodiphenylmethane, and phenylenediamine, and the properties of polyimide membranes were measured by experimental techniques. The dynamic sorption and transport processes of water vapor in those dense polyimide membranes were measured using computer on‐line recorded gravimetric sorption method at 298.15 and 308.15 K. Modeling of these processes involved the total change of excess Gibbs free energy, which was considered as a sum of three parts calculated by the modified Scatchard‐Hildebrand model, Flory‐Huggins theory, and linear viscoelastic theory, respectively. The calculated results were in agreement with the experimental data and the maximal relative deviation was no more than 8.57% and the average relative deviation is 4.62%. The calculated results had also shown that this model describe not only Fickian diffusion but also non‐Fickian very well. Furthermore, the influence of chemical structure, morphological structure, etc. of polyimide membranes on the water sorption concentration and water diffusion coefficient were interpreted by considering the experimental data and calculation results. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2189–2198, 2006
Effect of the medium on the stereostructure of poly(methyl methacrylate) synthesized in ionic liquids
Authors: Li Da , Zhang Yumei , Wang Huaping , Tang Jianzhong , Wang Biao 
Published: August 2006

AbstractPoly(methyl methacrylate) (PMMA) was synthesized in different ionic liquids (IL) by free radical polymerization. The average molecular weight and polydispersity of the PMMA were measured by gel permeation chromatography. It is found that ILs have effect not only on the molecular weights but also on the stereostructure of PMMA. From the FTIR and NMR analysis, it was confirmed that the chemical structure of PMMA synthesized in ILs was similar to the one obtained in conventional solvents while the stereostructure was influenced by the different IL used. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2199–2202, 2006
Preparation and characterization of a high molecular weight UV‐stabilizer based on a derivative of 2,4‐dihydroxybenzophenone and its application in polymer materials
Authors: Zhao Yi , Dan Yi 
Published: August 2006

AbstractIn this study, a polymerizable UV‐stabilizer, 2‐hydroxy‐4‐(3‐methacryloxy‐2‐hydroxylpropoxy)benzophenone (BPMA), was synthesized using 2,4‐dihydroxybenzophenone (UV‐0) and glycidyl methacrylate (GMA). It was copolymerized with methyl methacrylate (MMA) to prepare poly(MMA‐co‐BPMA) by emulsion polymerization. The composition and characteristics of poly(MMA‐co‐BPMA) were determined by using proton nuclear magnetic resonance (1H‐NMR), gel permeation chromatography (GPC), and ultraviolet‐visible absorption spectroscopy (UV–vis). Further, the obtained poly(MMA‐co‐BPMA) was used as a high molecular weight UV‐stabilizer and was blended with PVC to prepare PVC/poly(MMA‐co‐BPMA) films. These films were presented under UV light, using PVC film as standard substance. Insoluble substance, GPC, and color difference were used to characterize UV degradation. The results show that poly(MMA‐co‐BPMA) is an effective high molecular weight UV‐stabilizer. To detect the migration of poly(MMA‐co‐BPMA), water extraction and heat migration test were used to accelerate the movement of poly(MMA‐co‐BPMA). As a reference, these tests were also carried out on PVC/UV‐0 film. The results show that poly(MMA‐co‐BPMA) has very small migration, while nearly 80% UV‐0 migrated out from the plastic matrix after the experiments. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 102: 2203–2211, 2006
Cardanol‐based novolac‐type phenolic resins. I. A kinetic approach
Authors: Devi Archana , Srivastava Deepak 
Published: August 2006

AbstractNovolac resins having two different mole ratios of cardanol‐to‐formaldehyde (1:0.6 and 1:0.8) were prepared by using aliphatic tricarboxylic acid as catalyst at four different temperatures ranging between 100 and 130°C with an interval of 10°C. The synthesized novolacs were confirmed by infrared spectroscopic analysis with the appearance of characteristic groups of the novolac resin. The reaction between cardanol (C) and formaldehyde (F) was found to follow second‐order rate kinetics as determined by two different approaches. The over all rate constant (k) increased with the increase of C/F molar ratio. Based on the value of k, various other kinetic parameters such as activation energy (Ea), change in enthalpy (ΔH), entropy (ΔS), and free energy (ΔG) of the reaction were also evaluated. The values of Ea and ΔH were found to be decreased with the increase of C/F molar ratio from 1:0.6 to 1:0.8. These values revealed the nature of the condensation reaction between cardanol and formaldehyde in presence of tricarboxylic acid catalysts. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:2730–2737, 2006
Miscibility studies on chitosan/hydroxypropylmethyl cellulose blend in solution by viscosity, ultrasonic velocity, density, and refractive index methods
Authors: Jayaraju J. , Raviprakash S. D. , Keshavayya J. , Rai S. K. 
Published: August 2006

AbstractThe miscibility studies of chitosan (CHI)/hydroxypropylmethyl cellulose (HPMC) blend in buffer solution (0.1M acetic acid + 0.2M sodium acetate) were carried out by viscosity, ultrasonic velocity, density, and refractive index methods at 30, 40, and 50°C, respectively. Using viscosity data, the interaction parameter μ and α were computed. These values revealed that the blend is miscible when the CHI content is more than 50% in the blend. The obtained results were further confirmed by ultrasonic velocity, density, and refractive index study. And also the result revealed that the change in temperature has no significant effect on the miscibility of CHI/HPMC polymer blends. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2738–2742, 2006
Preparation of silvered polyimide films with reflective and electrically conductive surfaces using single‐stage self‐metallization techniques and factors affecting silver particles migration
Authors: Wu Zhanpeng , Wu Dezhen , Zhang Teng , Jiang Lizhong , Wang Wencai , Jin Riguang 
Published: August 2006

AbstractReflective and surface conductive flexible polyimide (PI) films were prepared by the incorporation of silver(I) acetate and 1,1,1‐trifluoro‐2,4‐pentanedione into a dimethylacetamide solution of several poly(amic acid)s which were prepared from dianhydrides and diamines. Thermal curing of the silver(I)‐containing poly(amino acid)s precursor led to cycloimidization of the PI with silver(I) reduction and formation of a reflective and conductive silvered surface at about 13 wt % silver. Effects on silver particles migration and aggregation were discussed in this article. The results indicated that the PI structures with flexible chains and groups easily fabricate the silvered films, with both reflective and conductive characteristics. With the forced air condition, the evaporation rate of the solvent and water increases, which facilitates the migration of silver particles to give reflective and conductive silvered surfaces. Films were characterized by transmission electron microscopy, scanning electron microscopy, and tapping‐mode atomic force microscopy. Electrical conductivity, reflectivity, and dynamic mechanical thermal analysis were performed on the metallized films. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2218–2225, 2006.
Orientation of montmorillonite clay in dicyclopentadiene/organically modified clay dispersions and nanocomposites
Authors: Yoonessi Mitra , Toghiani Hossein , Pittman Charles U. 
Published: August 2006

AbstractHighly delaminated dispersions of the organically modified clay I‐28 (Nanocor, Inc.) in liquid dicyclopentadiene (DCPD) were prepared.In situring‐opening metathesis polymerization of I‐28/DCPD nanodispersions generated I‐28/poly(DCPD) nanocomposites. When clay/DCPD dispersions were cured under shear, alignment of clay platelets, tactoids, and small particles was captured. This orientation was confirmed by X‐ray diffraction and transmission electron microscopy. The Herman's orientation parameters were calculated for the oriented nanocomposites. Viscosities of these liquid nanodispersions exhibited thixotropic flow behavior, prior to curing. The time‐dependent viscosity effects became more pronounced with an increase in delamination. Initial viscosities increased with progressive clay platelet generation during delamination and nanodispersion within the liquid monomer. Viscosity can be used to follow clay exfoliation/delamination. Etching the surface of a 2 wt % I‐28 clay/poly(DCPD) nanocomposite with oxygen plasma eroded the matrix, exposing clay tactoids protruding from the surface. These surfaces were examined by SEM and energy dispersive X‐ray spectroscopy. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2743–2751, 2006
Vinyl polymerization of norbornene over supported nickel catalyst
Authors: Hou Junxian , Jie Suyun , Zhang Wenjuan , Sun Wen‐Hua 
Published: August 2006

AbstractA series of nickel complexes, bis(salicylideneiminato)nickel(II), were supported on spherical MgCl2 and SiO2. Scanning electron microscopy, energy‐dispersed X‐ray spectroscopy, and the BET method for surface areas measurements were utilized to examine the supporting process of the catalysts. The particle morphology of the original support is retained and replicated throughout the supported catalyst preparation and norbornene polymerization. Spherical polymer particle morphology was achieved, without reactor fouling. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2233–2240, 2006
Molecular orientation of extruded PET/LCP blend films. Part I: Polarized infrared spectroscopy
Authors: Branciforti Marcia C. , Silva Lucineide B. , Bretas Rosario E. S. 
Published: August 2006

AbstractThe polarized infrared (IR) spectroscopy technique was used to evaluate the surface uniaxial molecular orientation of films of poly(ethylene terephthalate) (PET), two thermotropic liquid crystalline polymers (LCPs), Vectra®A950 and Rodrun®LC5000, and their blends obtained by extrusion. The molecular orientation of the LCP and of the crystalline and amorphous PET phases in the draw direction was evaluated along the transverse section of the films and as a function of the blend composition. A compatibilizer agent was used to improve the interfacial adhesion between the PET and LCPs. The results showed that the surface molecular orientation of both LCPs was very high along the draw direction. However, when blended, the orientation of the LCP phase decreased drastically, it was dependent of its content and varied along the transverse section of the extruded films. The maximum orientation was observed in the blend with 5 wt % LCP content and at the position where the shear rate was maxima. The LCP Vectra®A950 showed higher orientation than the Rodrun®LC5000, as a pure material and as blended. For the PET phases, an alignment of the amorphous phase in the draw direction due to the presence of LCP and compatibilizer agent was observed. The crystalline phase of PET, however, showed no significant orientation in the draw direction. The compatibilizer agent proved efficient for both PET/LCP systems. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2241–2248, 2006
Heat transfer in injection molding of crystalline plastics
Authors: Bai Yu , Yin Bo , Fu Xia‐rong , Yang Min‐gbo 
Published: August 2006

AbstractA theoretical mathematical model is presented to describe the temperature distribution and the rate of phase change in the injection molding process of crystalline plastics. Under some assumptions, an exact closed form is solved with the use of an internal technique. The model was tested by measuring the temperature profile in a slab mold instrumented with thermocouples. Measurements of temperature profiles in the center of the polymer slab compare well to model prediction. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2249–2253, 2006
Depolymerization of clean unfilled PTFE waste in a continuous process
Authors: Van Der Walt I. J. , Bruinsma O. S. L. 
Published: August 2006

AbstractA continuous process is described whereby waste PTFE was converted into tetrafluoroethylene (C2F4, TFE), hexafluoroethane (C2F6, HFE), hexafluoropropylene (C3F6, HFP), and octafluorocyclobutane (c‐C4F8, OFCB). The waste PTFE was depolymerized inside a reactor that was heated by a radiofrequency induction generator. The reactor was capable of operating at various temperatures (600–900°C) as well as various reduced pressures (5–80 kPa). The depolymerization reaction conditions could be changed while the reactor was in operation in order to manipulate the reaction product composition. Under certain conditions, high yields of TFE (> 94%) and low concentrations of by‐products were formed. The PTFE was fed vertically downward from the hopper, with the screw feeder, into the reactor where the depolymerization process took place. The hot intermediate products were continuously evacuated through a self‐cleaning quench probe, where it was quenched to form the final products. The depolymerized products were analyzed with a gas chromatograph. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2752–2759, 2006
Correlations between processing parameters, morphology, and properties of blown films of LLDPE/LDPE blends, part 2: Crystalline and amorphous biaxial orientation by WAXD pole figures
Authors: Branciforti Marcia C. , Guerrini Lilia M. , Machado Rogerio , Bretas Rosario E. S. 
Published: August 2006

AbstractThe biaxial molecular orientation of blown films made of blends of linear low density polyethylene (LLDPE) with low density polyethylene (LDPE) was characterized by two different methods: complete pole figures obtained by wide angle X‐rays diffraction (WAXD) and polarized infrared spectroscopy (IR) using the Krishnaswamy approach. The molecular orientation of the blends amorphous phase was also evaluated by polarized IR. The crystallinity of the blown films was determined by WAXD. A good correlation between the X‐ray pole figures and the polarized IR results was obtained. At all blends compositions, it was shown that the a‐axis of the polyethylene orthorhombic cell was preferentially oriented along the machine direction, the orientation degree along this direction increasing with the increase of the LDPE amount in the blends. The b‐axis changed its preferential orientation from film thickness in the 100/0 LLDPE/LDPE film to along the transverse direction with increasing LDPE in the blends. The c‐axis changed its orientation from orthogonal to normal direction in the 100/0 LLDPE/LDPE film to along the film thickness with increasing LDPE in the blends. Polarized IR characterization showed a negligible orientation of the amorphous phase. The amount of crystallinity was dependent on blend composition decreasing with the increase of LDPE content in the blends. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2760–2767, 2006
Synthesis of wood‐based epoxy resins and their mechanical and adhesive properties
Authors: Kishi Hajime , Fujita Akira , Miyazaki Hikaru , Matsuda Satoshi , Murakami Atsushi 
Published: August 2006

AbstractWood‐based epoxy resins were synthesized from resorcinol‐liquefied wood. Wood was first liquefied in the presence of resorcinol with or without a sulfuric acid catalyst at high temperature. Because of the hydroxyl groups, the resorcinol‐liquefied wood was considered as a precursor for synthesizing wood‐based epoxy resin. Namely, the phenolic OH groups of the liquefied wood reacted with epichlorohydrin under alkali condition. By the glycidyl etherification, epoxy functionality was introduced to the liquefied wood. The epoxy functionality of the resins was controlled by the concentration of phenolic OH groups in the liquefied wood, which would be a dominant factor for crosslink density and properties of the cured epoxy resins. The flexural strength (150–180 MPa) and the modulus of elasticity (3.2 GPa) of the highly crosslinked wood‐based epoxy resin were equivalent to those of the commercially available epoxy resin, diglycidyl ether of bisphenol A (DGEBA). Also, the shear adhesive strength of the wood‐based epoxy resin was higher than that of DGEBA when plywood was used as the adhesive substrates. The mechanical and adhesive properties suggested that the wood‐based epoxy resins would be well suited for matrix resins of natural plant‐fiber reinforced composites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2285–2292, 2006
Comparison of catalytic behaviors of various silica‐supported metallocene catalysts in syndiospecific polymerization of styrene
Authors: Yim Jin‐Heong , Ihm Son‐Ki 
Published: August 2006

AbstractHomogeneous metallocene catalysts and several kinds of silica‐supported metallocene catalysts were employed to investigate their catalytic behavior for styrene polymerization. Half metallocene directly supported on silica catalysts showed better performance than metallocene supported on silica treated with aluminum compounds with regard to syndiospecific styrene polymerization. The silica‐supported metallocene catalysts had optimum conditions for Al/Ti mole ratio and polymerization temperature. Among these, the Cp*TiCl3/SiO2 catalyst showed fairly good catalytic activity and yielded enhanced properties of syndiotactic polystyrene, even at a relatively low (< 300) Al/Ti mole ratio in styrene polymerization. Active sites formed on SiO2 appear to be more thermally stable as compared with their homogeneous counterparts. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2293–2298, 2006
Microstructures and optical features of polymer‐immobilized non close‐packed colloidal crystalline array
Authors: Nakamura Hiroshi , Mitsuoka Takuya , Ishii Masahiko 
Published: August 2006

AbstractWe have investigated to immobilize non close‐packed silica colloidal crystalline arrays in aqueous dispersion with hydrophilic polyethylene glycol acrylate polymer and to examine microstructures of the immobilized colloidal crystalline array by using the angle‐resolved reflection spectroscopy and scanning probe spectroscopy (SPM). Above nine of ethylene glycol chain length and below 10 wt % of monomer concentration in the dispersion, the structure of the three‐dimensional array in the aqueous dispersion is kept with immobilizing process. Angle‐resolved reflection spectra indicate refractive index increase, and interplaner spacing decreases with the increase of the particle volume fraction. The SPM phase images proved the crystal structure of the immobilized colloidal crystalline array of face‐centered cubic (fcc) structure. The interplaner spacings of the crystalline structure derived from angle‐resolved reflection spectra agree with those derived from SPM topographic images. We have demonstrated the microstructure of the polymer‐immobilized colloidal crystalline array directly and open the possibility of tuning the microstructure of colloidal crystalline array for photonic crystal. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2308–2314, 2006
Preparation and characterization of PVA/OMMT composites
Authors: Yürüdü Caner , İşçi Sevim , Ünlü Cüneyt , Atıcı Oya , Ece Ö. Işık , Güngör Nurfer 
Published: August 2006

AbstractIn this study, polyvinyl alcohol/organically modified montmorillonite (HDA/MMT; organoclay) composite was prepared for the intercalation processes. Firstly, the rheological behavior of aqueous montmorillonite dispersions was investigated as a function of solid content. Hexadecylamine (HDA) was added to the montmorillonite dispersion (2%, w/w) in different concentrations in the range of 5 × 10−4 – 9 × 10−3 mmol/L. The basal spacing of the organoclay (OMMT) was studied by X‐ray diffraction. The FTIR spectra are obtained from the modified montmorillonite products, which revealed the characteristic absorbencies after treatment with HDA. HDA/MMT/PVA composite, which was produced by the reaction of 1 wt % PVA solution with organoclay complex, is characterized by the rheology, electrokinetic, XRD, FTIR, and SEM techniques. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:2315–2323, 2006
Poly(amides) and poly(imides) containing silicon and germanium in the main chain: Synthesis, characterization and thermal studies
Authors: Tagle L. H. , Terraza C. A. , Leiva A. , Valenzuela P. 
Published: August 2006

AbstractPoly(amides) and poly(imides) containing the heteroatoms Si or Ge in the main chain and bonded to four carbon atoms were synthesized and characterized by IR and 1H, 13C and 29Si NMR. The acid dichlorides bis(4‐chloroformylphenyl)‐dimethylgermane, bis(4‐chloroformylphenyl)‐diphenylgermane, bis(4‐chloroformylphenyl)‐dimethylsilane, and bis(4‐chloroformylphenyl)‐diphenylsilane were synthesized from the ditolyl derivatives, which were oxidized to the respective diacids. The dianhydrides bis(3,4‐dicarboxyphenyl)‐dimethylgermane dianhydride, bis(3,4‐dicarboxyphenyl)‐diphenylgermane dianhydride, bis(3,4‐dicarboxyphenyl)‐dimethylsilane dianhydride, and bis(3,4‐dicarboxyphenyl)‐diphenylsilane dianhydride were synthesized from the dixylyl derivatives, which were oxidized to the tetraacids. Fully aromatic diamines also containing Si or Ge were synthesized from 4‐bromo‐N,N‐bis(trimethylsilyl)‐aniline and diphenyl‐dichlorosilane or germane. The ditolyl and dixylyl derivatives were synthesized from 4‐bromo‐toluene or 4‐bromo‐xylene and dimethyl‐ or diphenyl‐dichlorogermane, dimethyl‐ or diphenyl‐dichlorosilane. The glass transition temperatures and the thermal stability were determined showing in general that the polymers with Si atom in the main chain presented higher values of both parameters due to the higher ionic character of the CSi bond compared with the CGe one, and due to the lower size of the Si atom that presents lower rotational barriers. © 2006 Wiley Periodicals, Inc. J Appl PolymSci 102: 2768–2776, 2006
Polyolefins containing 1,3‐disubstituted cyclopentane units as nucleating agents for isotactic polypropylene
Authors: Naga Naofumi , Kitaura Koichi , Toyota Akinori 
Published: August 2006

AbstractPolyolefins containing 1,3‐disubstituted cyclopentane units in the main chain have been synthesized by 1,3‐polymerization of cyclopentene (PCP), cyclization polymerization of 1,5‐hexadiene (PHD), and ring‐opening metathesis polymerization of norbornene following hydrogenation of the unsaturated main chain (H‐PNB) with various transition metal catalysts. These polyolefins were applied to nucleating agents for isotactic polypropylene, and relationship between the structure of the polyolefins and nucleating effect was studied by DSC, polarized optical microscope, and WAXD. All the polyolefins had an effect of nucleation for isotactic polypropylene (PP). Of the polymeric nucleating agents, H‐PNB showed the most effective nucleation. Addition of PCP, which was obtained with a nickel catalyst with diimine ligand, to PP induced β‐modification. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2953–2958, 2006