bluuebunny/crossref_metadata_2025 huggingface dataset:
Redox initiation system of ceric salt and α,ω‐dihydroxy poly(dimethylsiloxane)s for vinyl polymerization
Authors: Öz Nesrin , Akar Ahmet
Published: August 2006

The redox system of ceric salt and α,ω‐dihydroxy poly(dimethylsiloxane) is used to polymerize vinyl monomers such as acrylonitrile and styrene to produce block copolymers. The concentration and type of α,ω‐dihydroxy poly(dimethylsiloxane) affects the yield and the molecular weight of the copolymers. The copolymers have about 20°C lower glass‐transition temperatures and much higher contact angle values than of the corresponding homopolymer of vinyl monomers, although the weight percent of α,ω‐dihydroxy poly(dimethylsiloxane) of the copolymers is in the range of 1–2%. © 2006 Wiley Periodicals Inc. J Appl Polym Sci 102: 2112–2116, 2006
Polypropylene–nanosilica‐filled composites: Effects of epoxy‐resin‐grafted nanosilica on the structural, thermal, and dynamic mechanical properties
Authors: Srinivasa Reddy Chaganti , Kumar Das Chapal
Published: August 2006

This article reports a comparative study of polypropylene (PP) nanocomposites synthesized with nanosilica (NS) and diglycidyl ether of bisphenol A, an epoxy‐resin‐grafted nanosilica (ENS), as nanofillers. These nanocomposites were prepared with the melt‐mixing method at a constant loading level of 2.5 wt %; this loading level was much lower than that used for fillers in conventional composites. The effects of pure NS and ENS on the thermal, structural, mechanical, and dynamic mechanical properties of PP were analyzed with wide‐angle X‐ray diffraction, transmission electron microscopy, thermogravimetric analysis, differential scanning calorimetry, dynamic mechanical analysis, and scanning electron microscopy. The transmission electron microscopy studies showed a better dispersion of ENS in the PP matrix, that is, in the polypropylene‐epoxy‐resin‐grafted nanosilica (PP–ENS) nanocomposite, in comparison with NS in the PP matrix, that is, in the polypropylene–nanosilica (PP–NS) nanocomposite. Also, the thermogravimetric analysis results showed a higher thermal stability for PP–ENS than PP–NS. Furthermore, the dynamic mechanical analysis studies showed an increase in the elastic modulus and glass‐transition temperature for PP–ENS with respect to PP–NS. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2117–2124, 2006
Spectroscopic, thermal, and electrical investigations of PVDF films filled with BiCl3
Authors: Hakeem N. A. , Abdelkader H. I. , El‐sheshtawi N. A. , Eleshmawi I. S.
Published: August 2006

Poly(vinylidene fluoride) (PVDF) films filled with BiCl3 in the mass fraction range of 0.1 ≤ W ≤ 10 were prepared. α‐ and β‐Crystalline PVDF phases were detected and characterized by spectroscopic analysis. Fourier transform infrared analysis detected the presence of α‐ and β‐phase head‐to‐head and tail‐to‐tail polymer chain defects. The band detected at 1670 cm−1 was assigned to CC, indicating polarons in the polymeric matrix. The degree of crystallinity increased by increasing the filling level (FL), and the maximum relative β‐phase content was found at w = 5% FL. This result was confirmed by X‐ray diffraction (XRD) and differential scanning calorimetry (DSC) analysis. The X‐ray analysis confirmed the presence of α and β phases, and no peaks corresponding to pure BiCl3 were found. DSC therograms showed a sharp endothermic peak at T1 = 444 K for different FLs because of the melting. This peak was used to calculate the activation energy and the order of the reaction. The DC electrical resistivity was attributed to the one‐dimensional interpolaron hopping mechanism. The FL dependence of log ρ and hopping distance (Ro) at 373 K was observed, indicating the FL affected the distribution of the hopping sites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2125–2131, 2006
Viscoelasticity and morphology of poly(ethylene‐co‐vinyl acetate)/polyisobutylene blends
Authors: Shumsky V. F. , Lipatov Y. , Getmanchuk I. , Usenko A. , Cassagnau P. , Boiteux G. , Melis F. , Lucas J.‐M.
Published: August 2006

Blends of an ethylene/vinyl acetate copolymer (EVA) and polyisobutylene of various compositions were prepared by mechanical mixing at a temperature above the melting point of EVA (TmEVA) but below the upper critical solution temperature of 170°C for given blends. The rheological properties of the components and blends were studied in the region of small‐amplitude oscillating deformation at temperatures above and below TmEVA in the frequency range of 0.01–100 rad/s. At temperatures lower than TmEVA, the rheological properties were determined by the existence of the yield stress. With diminishing frequency, the viscosity increased, and the plateau in the relaxation spectrum at low frequencies broadened. The morphology of the blends depended on the conditions of sample heating. The introduction of a finely dispersed filler into the blends led to an anomalous drop in the viscosity. The morphology of the systems that arose by mechanical blending of the molten components was the important factor in the rheological behavior. The observed effects were examined in the framework of the concept of structural networks formed in melts by nonmelted crystallites of EVA. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2700–2707, 2006
Use of nylon 6/polyethylene blends in the preparation of textile yarns
Authors: de Rezende Camila Alves , Schuchardt Ulf Friedrich , Gonçalves Maria do Carmo
Published: August 2006

Nylon 6 fibers are extensively used by the textile industry because of their excellent properties for yarn manufacturing. In this work, we show that it is possible to prepare yarns of reduced cost with blends of nylon 6 and polyethylene (PE), a lower priced polymer. Blends of nylon 6 and PE (nylon 6/PE) were tested in different compositions. Field emission scanning electron microscopy analyses and tensile tests showed better compatibilization in blends whose components had similar melt flow indices. Without adding compatibilizing agents, we incorporated up to 5 wt % PE into the nylon 6 matrix and successfully prepared yarns of nylon 6/PE blends on an industrial scale. Characterizing the yarns prepared from the blends by conventional techniques employed by the textile industry, we observed values very close to those presented by pure nylon 6 yarns, which indicated that the addition of small amounts of PE to the nylon 6 matrix could reduce the cost of the final yarns without changing significantly the properties of nylon 6. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2142–2148, 2006
Impact of melt impregnation on the color of wood–plastic composites
Authors: Zhang Yaolin , Zhang S. Y. , Chui Ying Hei
Published: August 2006

The aesthetics of wood–plastic composites (WPCs) can affect the acceptance of the products by consumers. This study was aimed at providing a better understanding of how impregnation variables affect color changes, thereby allowing for the development of an optimal process for WPCs. The effects of impregnation parameters and impregnants on the WPC color were investigated in this study via a screening design. Sixteen runs of resolution IV design for seven factors at two levels were conducted. The seven factors were the ratio of maleated polyethylene in the formulations, the ratio of polyethylenes with different molecular weights, four process factors (vacuum, pressure, time, and temperature), and wood species (red maple and aspen). The studied color parameters included the lightness change, chroma change, hue angle change, saturation change, and total color change. All treatments darkened the wood and increased the chroma values and the saturation. Even though all treatments had an impact on the hue angle, the changes were very small. The wood species, impregnants, impregnation time, and temperature played significant roles in the color change and chroma coordinates. However, no parameter dominated the hue angle change and saturation. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2149–2157, 2006
Reflective and electrically conductive palladium surface‐metallized polyimide nanocomposite membranes
Authors: Davis Luke M. , Compton J. M. , Kranbuehl D. E. , Thompson D. W. , Southward R. E.
Published: August 2006

A previous article (Southward and Thompson, Chem Mater 2004, 16, 2091) focused on the characterization of surface metallized palladium‐BTDA/4,4′‐ODA (3,3′,4,4′‐benzophenone tetracarboxylic dianhydride‐4,4′‐oxydianiline) hybrid membranes formed by in situ reduction of Pd2+ to Pd○ during thermal imidization of the poly(amic acid) via the protocol of St. Clair et al. (J Am Chem Soc 1980, 102, 876). The present work extended the Pd‐polyimide metallization synthesis to the BPDA/4,4′‐ODA (3,3′,4,4′‐biphenyltetracarboxylic dianhydride‐4,4′‐ODA) polymer. The effects of the Pd2+ ligand on the reductive metallization of BTDA/4,4′‐ODA were also examined for the PdCl2(SMe2)2, PdBr2(SMe2)2, and Pd(CF3COO)2 complexes. The hybrid films were characterized by specular and diffuse reflectivity and by conductivity measurement. Maximum specular reflectivity was in the range of 35%–55%, and conductivity was in the range of 1–10 Ω/square. Scanning electron microscopy and transmission electron microscopy revealed that the initial Pd metal particles formed within the films were in the 3–8 nm range in size. These particles increased in size with irregular shapes at the surface as the metallic exterior emerged. A fraction of the nanometer‐sized Pd particles remained uniformly distributed throughout the bulk of the film. The mechanism for the formation of a metallic surface required selective oxidative degradation of the polyimide at the polyimide–air interface. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2708–2716, 2006
Inhibitive properties of cationic polymers in a borehole environment
Authors: Souza C. E. C. , Fonseca M. V. , Sá C. H. , Nascimento R. S. V.
Published: August 2006

The adsorption behavior of poly(diallyldimethylammonium chloride) (PDADMAC) and of a copolymer with acrylamide on a native clay was studied as a function of the molecular weight of homopolymers, the ionic strength of the medium, and the ionic nature of the constituent blocks of the polymers. The clay was used without further purification or treatment in order to simulate a borehole environment. The properties of the clay–polymer systems studied were evaluated through total organic carbon analysis, thermogravimetric analysis (TGA), and X‐ray diffraction analysis. The adsorption isotherms showed that all cationic polymers had high affinity for the clay, even in a highly saline medium and that the amount of polymer adsorbed strictly depended on the length of the macromolecular chain. The TGA results showed that polymer adsorption was able to reduce the water content of the clay surfaces, independently of the molecular weight of the homopolymer. The inhibitive properties of the polycations were measured by conventional oilfield cuttings rolling tests, which showed that these polymers were able to reduce the dispersion and disintegration of the clay cuttings. The results also showed that inhibition was directly related to the clay–polymer interactions and, therefore, to the polymer structure. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2158–2163, 2006.
Thermally bonded nonwoven filters composed of bi‐component polypropylene/polyester fiber. II. Relationships between fabric area density, air permeability, and pore size distribution
Authors: Wang X. Y. , Gong R. H.
Published: August 2006

The relationships between the pore size, fabric area density, and air permeability of the three‐dimensional (3D) nonwoven filter samples produced using a new 3D forming process has been studied. Results indicate that the thermally bonded nonwoven filter samples consist of multiple filtration layers of interconnected pores and tortuous pore paths through the fabric thickness. Both the bubble point pore diameter and the mean flow pore diameter of the produced filter samples increase linearly with increase in the reciprocal of the fabric area density. The air permeability of the nonwoven filter samples decreases significantly to a certain value with increasing fabric area density, and then becomes almost stable with further increasing of fabric area density. The measured pore size data in the thermally bonded nonwoven samples were found to follow all the bi‐normal, bi‐lognormal, and bi‐Weibull distributions. Taken into account together the pore structure, pore size distribution, air permeability, and fabric area density, the new 3D forming system can substitute most of the commercial polyester filter media with significantly reduced costs. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2264–2275, 2006
Interpolymer interactions and miscibility in poly(n‐butyl methacrylate‐co‐methacrylic acid)/poly(styrene‐co‐N,N‐dimethyl acrylamide) blends
Authors: Hadj‐Hamou Assia Siham , Djadoun Said
Published: August 2006

The miscibility of poly(n‐butyl methacrylate‐co‐methacrylic acid) containing 18 mol % methacrylic acid (BMAM‐18) and poly(styrene‐co‐N,N‐dimethyl acrylamide) containing 17 mol % N,N‐dimethyl acrylamide (SAD‐17) was investigated with viscometry, differential scanning calorimetry (DSC), and Fourier transform infrared (FTIR) spectroscopy. The DSC analysis showed a single glass‐transition temperature for all the blends, indicating that these copolymers were miscible over the entire composition range. The glass‐transition temperatures of these blends were higher than those calculated with the additivity rule. This was characteristic of the presence of specific interactions. The interactions between BMAM‐18 and the tertiary amide of SAD‐17 were studied with FTIR spectroscopy, which revealed that hydrogen‐bonding interactions occurred between the hydroxyl groups of BMAM‐18 and the carbonyl amide of SAD‐17. A new band characterizing these interactions appeared around 1613 cm−1. The quantitative results showed that the fraction of the associated amide increased with an increase in the amount of the acidic BMAM‐18 copolymer. Although BMAM‐18 and SAD‐17 led to homogeneous solutions in butan‐2‐one, as the concentration of N,N‐dimethyl acrylamide increased to 32 mol % [as within the poly(styrene‐co‐N,N‐dimethyl acrylamide) containing 32 mol % N,N‐dimethyl acrylamide], complexation occurred when this latter compound was mixed with BMAM‐18 in butan‐2‐one. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2717–2724, 2006
High‐performance filaments from compatibilized polypropylene/clay nanocomposites
Authors: Joshi M. , Viswanathan V.
Published: August 2006

Polypropylene (PP)/nanoclay composite filaments were produced by melt spinning and characterized to study the effect of the compatibilizer and the role of the nanoclay in improving the physical properties. The compatibilizer was maleic anhydride grafted PP. Clay loadings up to 1 wt % with up to 3 wt % compatibilizer were explored. There was a significant improvement in the tensile, thermal, and dynamic mechanical properties and creep resistance of PP/nanoclay composite filaments over neat PP filaments at very low clay loadings of 0.25–0.5 wt % and a compatibilizer/clay ratio of 2:1. The properties were correlated to the morphology of the nanocomposite filaments, which was investigated with differential scanning calorimetry, X‐ray diffraction, and transmission electron microscopy. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2164–2174, 2006.
A high‐performance positive‐working photosensitive polyimide: Effects of reactive end groups on the physical properties of the films
Authors: Jung Myung‐Sup , Joo Won‐Jae , Kwon Ohyun , Sohn Byung H. , Jung Hee‐Tae
Published: August 2006

To investigate the effects of reactive end‐cappers on the performance of PI precursors and the resulting polyimide (PI) films, poly(amic acid)s (PAAs) as a base polymer of the positive‐working photosensitive polyimides (PSPIs) were synthesized via ring‐opening polymerization of 4,4′‐oxydiphthalic anhydride and 4,4′‐oxydianiline with four different reactive end‐cappers [maleic anhydride, citraconic anhydride, 2,3‐dimethylmaleic anhydride (DMA), and 5‐norbornene‐2,3‐dicarboxylic anhydride (NDA)]. During imidization of these end‐capped PAAs to form the corresponding PI films, chain extension and crosslinking reactions of the respective end groups occurred, resulting in an improvement in the mechanical and thermal properties despite the low molecular weight of the precursors. However, the UV transmittance at ˜365 nm, an important property of PSPIs for thick‐film applications, such as stress buffer layers, was strongly influenced by the type of end‐capper used. These behaviors were understood in terms of the optimized geometries and the simulated UV–vis spectra of modeled end groups determined from density functional theory calculations. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:2180–2188, 2006
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

Series 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

Poly(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

In 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

Novolac 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

The 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

Reflective 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

Highly 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

A 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

The 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

A 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

A 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

The 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

Wood‐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

Homogeneous 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

We 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

In 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

Poly(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

Polyolefins 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
Gas permeability analysis of photo‐cured cyclohexyl‐substituted polysiloxane films
Authors: Dworak D. P. , Lin H. , Freeman B. D. , Soucek M. D.
Published: August 2006

A photo‐cured cyclohexyl‐substituted polysiloxane (PDCHS) film was prepared and compared with polydimethylsiloxane (PDMS) for the determination of permeability coefficients using various penetrants (H2, N2, O2, CO2, CH4, C3H6, and C3H8). Penetrant sorption isotherms and local effective diffusion coefficients as a function of local penetrant concentration were also determined. The crosslink density of the films was measured via dynamic mechanical thermal analysis and was found to be 6.46 × 104 mol/m3 for PDMS and 1.82 × 103 mol/m3 for PDCHS. Photo‐differential scanning calorimetry was used to calculate percent conversion under the conditions used for curing and was found to be (99.6 ± 0.3)% for PDMS and (98.4 ± 0.3)% for PDCHS. When cured, the PDCHS films had a lower crosslink density and lower permeance. It was postulated that the cycloaliphatic substitution along the polysiloxane backbone may not have full rotational ability affording closer intermolecular interactions, thus reducing the available free volume. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:2343–2351, 2006
Insert‐molded poly(ether imide)/carbon fiber poly(ether ether ketone) bimaterial composites: Fracture and interfacial analysis
Authors: In Moon Sung , Monson L. L. , Extrand C. W.
Published: August 2006

Bimaterial composites were constructed by injecting carbon‐fiber‐filled poly(etheretherketone) (CF PEEK) into a mold containing one‐half of a poly(etherimide) (PEI) tensile specimen. Specimens were notched at the interface and tested in tension. Using fracture mechanics, the adhesion strength of the interface (a fracture energy with units of energy per area) was calculated from notch size and stress–strain behavior of the notched specimens. Fracture energies (with units of energy per area) of the PEI/CF PEEK bimaterial composites were slightly less than those measured from the monolithic materials of construction. Variations in test speed (below the glass transition temperature of the two components) had little effect on stiffness or fracture energy. However, fracture energies decreased slightly as temperature increased. Composites fractured through the CF PEEK near the PEI/CF PEEK interface. Consequently, the fracture surface of the PEI portion had a thin layer of CF PEEK (a qualitative indicator of good adhesion). Microscopy and X‐ray photoelectron spectroscopy confirmed the presence of a thin layer of CF PEEK on the PEI. It appears that the miscibility of PEI and PEEK contributed to the strength of the PEI/CF PEEK thermophysical bond. The strength of the thermophysical bond of the PEI/CF PEEK bimaterial composites was greater than the cohesive strength of amorphous commodity polymers such as polystyrene and should be more than adequate for most microelectronics device handling applications. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:2362–2371, 2006
Diffusion of seawater in unsaturated polyester resin and its glass fiber reinforced composites in the presence of titanium dioxide as UV absorber
Authors: Urs M. V. Deepa , Ranganathaiah C. , Ramani R. , Lal Babu , Alam Sarfaraz
Published: August 2006

Diffusion of seawater in unsaturated polyester resin (UPR) and its glass fiber reinforced composite in the presence of titanium dioxide has been studied by sorption method. Incorporation of glass and TiO2 to UPR alters the seawater diffusion process from Fickian to non‐Fickian type. The dual mode sorption model is used to separate Fickian‐controlled and relaxation‐controlled diffusion in case of UPR‐T, UPR‐G, and UPR‐GT. The presence of TiO2 seems to stabilize UPR and its glass reinforced samples but an increase in the rate of seawater diffusion is observed for these systems. The free volume determined from positron lifetime measurements support the diffusion data in these systems. Results further indicate that the contribution to diffusion in the later stages of sorption is due to the increased contribution from the interfaces. The plasticizing effect of TiO2 is clearly seen even in the glass reinforced composite. DMA results show an increase in flexibility because of TiO2 presence both in the neat as well as glass reinforced resin which is well supported by decrease in Tg value from DSC data. © 2006 Wiley Periodicals, Inc. J Appl PolymSci 102: 2784–2794, 2006
Dispersion polymerization of acrylamide with 2‐acrylamido‐2‐methyl‐1‐propane sulfonate in aqueous solution
Authors: Wu Y. M. , Wang Y. P. , Yu Y. Q. , Xu J. , Chen Q. F.
Published: August 2006

The copolymer of acrylamide (AM) and 2‐acrylamido‐2‐methyl‐1‐propane sulfonate (AMPS) was synthesized through the free radical dispersion polymerization in an aqueous solution of ammonium sulfate and in the presence of poly(2‐acrylamido‐2‐methyl‐1‐propane sulfonate) as stabilizer. The average particle size of the copolymer ranged from 1 to 4 μm, and the molecular weight was from 2.0 × 106 to 7.0 × 106 g mol−1. By analyzing apparent viscosity and particle size, the swelling property of the dispersion copolymer was studied. When the dispersion was diluted with salt water in which the ammonium sulfate concentration kept equal with that of the original dispersion, particle size and particle size distribution of the diluted dispersion changed a little, compared with that of the original dispersion. While diluted with deionized water, particle size and particle size distribution could expand several times. The effects of varying concentrations of the stabilizer, the monomer, the salt and the initiator on particle size, and molecular weight of the copolymer were investigated, respectively. The reaction conditions for preparing stable dispersion were concentrations of 20–28% of the salt, 6–14% of monomers, and 1.8–2.7% of the stabilizer. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:2379–2385, 2006
A synergistic effect of nano‐Tio2 and graphite on the tribological performance of epoxy matrix composites
Authors: Xian Guijun , Walter Rolf , Haupert Frank
Published: August 2006

The influence of incorporated 300 nm TiO2 (4 vol %), graphite (7 vol %), or combination of both fillers on the tribological performance of an epoxy resin was studied under various sliding load (10–40 N) and velocity conditions (0.2–3.0 m/s). Mechanical measurements indicated that the incorporation of TiO2 significantly enhanced the flexural and impact strength of the neat epoxy and the graphite including epoxy. Tribological tests were conducted with a cylinder‐on‐flat testing rig. The incorporation of nano‐TiO2 significantly improved the wear resistance of the neat epoxy under mild sliding conditions; however, this effect was markedly diminished under severe sliding conditions (high velocity and normal load). Nano‐TiO2 reduced the coefficient of friction only under severe sliding conditions. Graphite showed a beneficial effect in reducing the wear rate and the coefficient of friction of the neat epoxy. Compared to the nano‐TiO2‐filled epoxy, the graphite‐filled epoxy showed more stable wear performance with the variation of the sliding conditions, especially the normal load. A synergistic effect was found for the combination of nano‐TiO2 and graphite, which led to the lowest wear rate and coefficient of friction under the whole investigated conditions. The synergistic effect was attributed to the effective transfer films formed on sliding pair surfaces and the reinforcing effect of the nanoparticles. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2391–2400, 2006
Separation of ethylbenzene from C7+‐cut naphtha
Authors: Faridi‐Majidi Reza , Sharifi‐Sanjani Naser , Zand Eissa Khani Ramin , Barari Mohammad
Published: August 2006

A fractional distillation process for separating ethylbenzene (EB) from a feed mixture C7+‐cut naphtha, comprising nonaromatics, BTX, EB, styrene, and C8+ fraction, was used. Primarily, 29.63 wt % EB in the bottom was obtained. Redistillation of the bottom component produced 63.98 wt % EB in the 2nd cut; finally, this cut was used as a feed to distillation process and 83.21 wt % EB was obtained in distillate, and this feed was used directly for dehydrogenation process to produce styrene monomer. All of the distilled fractions were analyzed by gas chromatography instrument. © 2006 Wiley Periodicals, Inc. J Appl PolymSci 102: 2795–2798, 2006