bluuebunny/crossref_metadata_2025 huggingface dataset:
Heat‐treated softwood exposed to weathering
Authors: Nuopponen Mari , Wikberg Hanne , Vuorinen Tapani , Maunu Sirkka L. , Jämsä Saila , Viitaniemi Pertti
Published: December 2003

Scots pine samples, heat‐treated (225°C under steam) and reference (kiln‐dried), were exposed to natural weathering for 7 years in Espoo, Finland. The weathered and unweathered samples were examined with FTIR, UV resonance Raman, and 13C CPMAS NMR spectroscopies. The spectroscopic results revealed that the lignin contents of the weathered heat‐treated and especially of the weathered reference softwood samples diminished significantly. The surface of the weathered heat‐treated sample was still rich in aromatic and conjugated carbonyl structures, whereas the surface of the reference sample was enriched with cellulose. These results indicated that weathering products of lignin were leached out with water from the reference sample, whereas in the heat‐treated wood they were largely unleachable. The structure of the heat‐treated wood was modified and degradation products did not leach out as easily as in the case of the reference sample. The weathering also resulted in a decreased content of amorphous polysaccharides of the reference sample, whereas the changes in the polysaccharide contents between weathered and unweathered heat‐treated samples were not as dramatic because the amorphous carbohydrates were already degraded in the heat treatment. The results indicated that heat‐treated wood is more resistant to natural weathering than untreated wood. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2128–2134, 2004
Photooxidation and stabilization of photooxidized polyethylene and of its monopolymer blends
Authors: La Mantia F. P. , Tzankova Dintcheva N.
Published: December 2003

The increasing use of products from recycled polymers, or from blends with recycled polymers exposed to the outdoors, implies the need for good weathering resistance. This is particularly important when the recycled material comes, in turn, from products exposed during their lifetime to the sun. In this case the presence of CO groups in the macromolecular chains strongly increases the photooxidative degradation kinetics of these secondary materials. In this work the change of the photooxidative degradation of blends of virgin and photooxidized polyethylene was evaluated as a function of the CO content present in the material. As expected, the presence of the CO groups strongly increases the photooxidation kinetics, as revealed by the increase of the carbonyl compounds, and by the decrease of the elongation at break. It was confirmed that the increase of CO groups is dependent on the content of the same groups, whereas this is not true for the mechanical properties. The use of UV stabilizer strongly improves the weathering resistance of these materials, which become almost insensitive to the initial amount of CO groups. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2244–2255, 2004
The effect of methods of introducing acrylic emulsions grafted with acetoacetyl groups on the properties of particleboards
Authors: Dziurka Dorota , Łȩcka Janina
Published: December 2003

The aim of this study was to investigate the effect of compounds, either spread on particles or added to the resin, which contain various numbers of acetoacetyl groups in terms of their effect on formaldehyde content and the physical and mechanical properties of particleboards glued with the urea‐formaldehyde (UF) resin. The produced particleboards were subjected to the following European Standards standard tests: internal bond, modulus of rupture, modulus of elasticity, swelling in thickness after 24 h of soaking in water, and the content of formaldehyde. Results of the study make it possible to state that both the spreading of the acrylic emulsions containing acetoacetyl groups on the particles before gluing and the adding of them to the UF resin result in a decrease of formaldehyde content and improvement of physical and mechanical properties of particleboards. Boards with better properties were obtained in the case when emulsions containing acetoacetyl groups were spread directly on the surface of particles. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2256–2264, 2004
Density‐based phase‐separation asymmetric polyethylene–poly(dimethyl siloxane) blend membranes: Preparation and properties
Authors: Pandey Pratibha , Chauhan R. S. , Semwal R. P. , Banerjee S. , Jain Rajeev
Published: December 2003

A new concept of density‐based phase separation for the preparation of asymmetric membranes from polyethylene (PE) blended with liquid poly(dimethyl siloxane) (PDMS) has been tried. The PE/PDMS membranes were prepared via high‐temperature solution casting. The purpose of incorporating PDMS was to utilize its flexibility, relatively high density in comparison with PE, and dissolution in common solvent for the formation of asymmetric PE/PDMS membranes. The study has been carried out with 1.25, 2.5, 5, and 10% (v/w) loading of PDMS. A host of techniques were used to study morphology of PE/PDMS blend membranes. The membranes show nodular structure on surfaces in contact with solvent vapor environment, whereas the opposite surfaces have smoother texture devoid of nodules. Although differential scanning calorimetric (DSC) melting endotherms indicate enhancement of crystallinity with PDMS addition, chemical etching and subsequent scanning electron microscopic (SEM) observations show increasingly ordered spherulitic pattern on individual nodules with the incorporation of PDMS up to 2.5%. The density of the films also increases with the addition of PDMS as compared to the control. ATR‐FTIR data revealed asymmetric distribution of PDMS in membranes with more PDMS retention toward lower surface of membranes. Membrane cross sections were indicative of graded porosity with increasing pore size toward the bottom surface of membranes. The results were explained in terms of density‐based phase separation.© 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91:2278–2287, 2004
Thermal degradation of the polyimide synthesized from 4,4′‐(hexafluoroisopropylidene) diphthalic dianhydride and 4,4′‐diaminodiphenylmethane
Authors: Ren Li , Fu Weiwen , Luo Yuanfang , Lu Hui , Jia Demin , Shen Jiarui , Pang Bei , Ko Tze‐Man
Published: December 2003

The thermal degradation of polyimide PIF2 synthesized from 4,4′‐(hexafluoroisopropylidene) diphthalic dianhydride and 4,4′‐diaminodiphenylmethane was systematically and thoroughly investigated by high‐resolution pyrolysis gas chromatography/mass spectrometry, thermogravimetric analysis, and Fourier transform infrared spectroscopy. The pyrolyzates of PIF2 were dependent on the pyrolysis temperature. Two weight‐loss peaks were observed in the derivative thermogravimetric analysis of PIF2 and the first peak was related to the fluorine‐containing segment (hexafluoroisopropylidene). The overall activation energy and preexponential factor were calculated through dynamic TGA with Ozawa's method. Based on the results, a thermal degradation mechanism of the PIF2 was proposed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2295–2301, 2004
Electrochemical polymerization of fluoro‐ and chloro‐substituted anilines and copolymers with aniline
Authors: Şahin Yücel , Perçin Sabriye , Şahin Mutlu , Özkan Güleren
Published: December 2003

Poly(2‐fluroaniline) and poly(2‐chloroaniline) were synthesized by an electrochemical method in an acetonitrile solution containing tetrabutylammonium perchlorate and perchloric acid. Also, the electrochemical copolymerization of aniline with 2‐fluroaniline and 2‐chloroaniline was carried out in the same medium. Cyclic voltammograms of the deposited films were recorded in neutral, acidic, and basic solutions. The electrochemical behavior of the films showed the same characteristic results as conventional polyaniline. The observed decrease in the dry electrical conductivity of the copolymers with respect to polyaniline was attributed to the incorporation of the fluoro‐ and chloro‐substituted anilines into the polyaniline chain. Further characterization of the polymer and copolymer products was performed through dry electrical conductivity measurements, ultraviolet–visible spectroscopy, and Fourier transform infrared spectroscopy. The relative solubility of the films was determined in various common organic solvents. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2302–2312, 2004
Maleic anhydride grafted polypropylene as a coupling agent for polypropylene composites filled with ink‐eliminated waste paper sludge flour
Authors: Qiao Xiuying , Zhang Yong , Zhang Yinxi
Published: December 2003

Ink‐eliminated sludge flour (IESF), a waste residue from the recycling treatment of waste paper, is a promising new kind of filler for thermoplastic polymers with a good price/performance ratio and advantages for environmental protection. In this study, high‐impact polypropylene (PP) and maleic anhydride grafted polypropylene (MAPP) were chosen as a polymer matrix and a coupling agent, respectively, for the preparation of IESF/PP composites, and the structures and properties of the obtained composites were also investigated. The experimental results revealed that IESF not only induced the crystallization orientation of PP along the b axis but also had a restraining effect on the formation of the β phase during the recrystallization of PP from the melt; the addition of MAPP further strengthened this effect to some extent. In addition, the proper addition of MAPP was helpful for improving the thermal stability of the IESF/PP composites. With the strengthening of the interfacial interaction between the IESF and PP matrix by MAPP, the resultant efficient stress transfer from the PP matrix to the IESF particles led to increased tensile and flexural strength. However, the original greater rigidity of MAPP, with respect to PP, reduced the toughness of the composites and caused some negative effects on the impact strength and the elongation at break. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2320–2325, 2004
Stability of high‐bandwidth graded‐index polymer optical fiber
Authors: Dai Xinhua , He Jun , Liu Zhimin , Ai Xicheng , Yang Guanying , Han Buxing , Xu Jian
Published: December 2003

The properties of poly(methyl methacrylate) (PMMA)‐based graded‐index polymer optical fiber (GI POF), including the thermal stability, thermal humidity, and mechanical properties, were studied for polymer optical fiber research and applications. The glass‐transition temperature of the fiber core was 103°C in the presence of the dopant, which was close to that of the PMMA matrix without the dopant. A special refractive‐index profile derived from the distribution of the dopant was stable at 60°C. Moreover, GI POF exhibited good mechanical properties. The excellent performance indicated that GI POF could be applied not only for indoor use but also for outdoor use. However, PMMA‐based GI POF exhibited poor hot‐water/humidity resistance. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2330–2334, 2004
Ultraviolet curing of liquid polysulfide thiourethane acrylate
Authors: Quan Yi Wu , Dong Wen Zhao , Fang Jiang Ling , Chen Qing Min
Published: December 2003

A series of liquid polysulfide thiourethane acrylate prepolymers were synthesized by the reaction of liquid polysulfide with isocyanate and hydroxyethyl acrylate. With and without a combination of acrylic monomers, the prepolymers were cured with ultraviolet radiation. The films exhibited a higher soft‐segment glass‐transition temperature than metal oxide cured polysulfide. With the addition of a diluent, the tensile strength and modulus increased, whereas the ultimate elongation decreased. The polysulfide backbone, combined with the crosslink generated from the photopolymerization of acrylic, produced films with superior oil resistance. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2358–2363, 2004
Phase‐transfer‐agent‐aided polymerization and graft copolymerization of acrylamide
Authors: Kaur Inderjeet , Singh Baljit , Upasana
Published: December 2003

The use of phase‐transfer catalysts, with water‐insoluble initiators, for polymerization and graft copolymerization reactions was explored. The polymerization of a water‐soluble vinyl monomer, acrylamide (AAm), and the graft copolymerization of AAm onto a water‐insoluble polymer backbone, isotactic polypropylene (IPP), with a water‐insoluble initiator, benzoyl peroxide (BPO), and a phase‐transfer catalyst, tetrabutyl ammonium bromide (Bu4N+Br−), were carried out in a water/xylene binary solvent system. The conversion percentage of AAm into polyacrylamide (PAAm) and the percentage of grafting of AAm onto IPP were determined as functions of various reaction parameters, such as the BPO, AAm, and phase‐transfer‐catalyst concentrations, the amounts of water and xylene in the water/xylene mixture, the time, and the temperature. The graft copolymer, IPP‐g‐PAAm, was characterized with IR spectroscopy and thermogravimetric analysis. By a comparison of the results of the phase‐transfer‐catalyzed graft copolymerization of AAm onto IPP and the preirradiation method, it was observed that the optimum reaction conditions were milder for the phase‐transfer‐catalyst‐aided graft copolymerization. Milder reaction conditions, including the temperature, the time of reaction, and a moderate initiator (BPO), in comparison with high‐energy γ‐rays, led to better quality products, and the reaction proceeded smoothly with high productivity. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2364–2375, 2004
Investigation of the influence of CuO filler and carbon fiber on wear and transfer film of nylon composites
Authors: Wang Jun‐Xiang , Gu Ming‐Yuan
Published: December 2003

Nylon 1010 composite specimens were prepared with CuO filler and short carbon fiber (CF) as the reinforcement. Friction and wear behavior of composite materials was investigated in a ring‐block wear tester. The results show that carbon fiber was more effective in reducing friction and wear of nylon than CuO filler. Nylon composite with 20% CF and 10% CuO content filler had the lowest wear rate that could not be obtained with any proportion of the fiber or the filler alone. It was found that the transfer film on the counterpart of 20% CF–10% CuO–nylon was thin, continuous, and uniform. These differences in tribological performance have been studied according to the synergism between the carbon fiber and CuO filler. The tribochemical studies by X‐ray photoelectron spectroscopy (XPS) revealed that pure Cu, Cu2O, and Cu(OH)2 were produced due to the decomposition of CuO during sliding. Carbon fiber promoted the process of tribochemical reactions of CuO, which generated more pure Cu particle and then self‐lubricating transfer film including pure Cu was formed on the steel counterpart.© 2003 Wiley Periodicals,Inc.J Appl Polym Sci 91: 2397–2401, 2004
Effect of organophilic montmorillonite on polyurethane/montmorillonite nanocomposites
Authors: Han Bing , Cheng Aimin , Ji Gending , Wu ShiShan , Shen Jian
Published: December 2003

Different kinds of organophilic montmorillonite cotreated by cetyltrimethyl ammonium bromide (CTAB) and aminoundecanoic acid (AUA) were synthesized and applied to prepare polyurethane/montmorillonite nanocomposites via solution intercalation. The results of wide‐angle X‐ray diffraction (WAXD) and transmission electron microscopy showed that, for the montmorillonite modified with CTAB and CTAB/AUA (molar ratio of 1/2), an ordered intercalated nanostructure was derived, while for the montmorillonite treated with AUA, a disordered nanostructure was derived. The tensile properties of the polyurethane (PU) nanocomposites showed higher enhancement relative to PU matrix. TG showed that there is some enhancement in degradation behavior between the nanocomposites and PU matrix. DMTA results showed that nanocomposites from some organophilic montmorillonites showed a much higher storage modulus below and above glass transition temperature, while the nanocomposites from montmorillonite treated by AUA show an even lower storage modulus. The loss curves showed that the main glass transition temperature of PU was improved to some extent for the nanocomposites. The water absorption of PU and nanocomposites was also studied and the difference in reduction was thoroughly analyzed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2536–2542, 2004
Correlating the crystallization kinetics of syndiotactic polystyrene
Authors: Hieber C. A.
Published: December 2003

The Nakamura equation is used to model the crystallization kinetics of syndiotactic polystyrene. Model constants are generated by fitting available data under isothermal conditions. The resulting fit is then applied to available data under constant‐cooling‐rate conditions, with notable agreement provided the measurements include corrections for thermal lag. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2402–2406, 2004
Study on the structure and processibility of the iodinated poly(vinyl alcohol). I. Thermal analyses of iodinated poly(vinyl alcohol) films
Authors: Shin Eun Joo , Lee Yang Hun , Choi Suk Chul
Published: December 2003

To get more information on the structure of iodinated poly(vinyl alcohol) (PVA), thermal analyses of unoriented and oriented PVA films were conducted. Unoriented and oriented PVA films iodinated with aqueous solutions at selected concentrations were carried out by thermogravimetry (TG) and differential scanning calorimetry (DSC). The TG curves for the iodinated film shows four or five weight‐loss zones associated with degradation and evaporation of excess I2 molecules and I2 molecules from I, partial OH side groups on PVA, and I2 from I, the remaining OH groups and the partial main chains, the remaining main chains, and a very small amount of residue from PVA. The char of KI salts remained. By investigating the TG results, it was identified that the amount of I ions increased with increasing I2/KI up to 65%, but above that weight gain, the rate of increase diminished and the amount of I ions from the I ions increased. The TG curve for the oriented film was very similar to that for the unoriented film except for its greater weight loss at zone I due to narrow space in amorphous region. The DSC thermogram of iodinated films indicated two peaks at 145°C and 160–170°C, corresponding to the melting of crystals and the degradations of OH groups and main chains, respectively. The maximum temperatures of peaks were much lower than that of the untreated one. ©2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2407‐2415, 2004
Study of sulfonation mechanism of low‐density polyethylene films with fuming sulfuric acid
Authors: Kaneko Masashi , Kumagai Satoshi , Nakamura Tatsuo , Sato Hisaya
Published: December 2003

Sulfonation of low‐density polyethylene (LDPE) films with fuming sulfuric acid was studied by X‐ray photoelectron spectroscopy (XPS) and attenuated total reflectance (ATR) infrared spectroscopy. The ATR spectra showed the formation of CC double bonds and multiple sulfur atom containing groups for the sulfonation of LDPE films. This led us to propose that the abstraction reaction of hydride ion by sulfur trioxide (SO3) in fuming sulfuric acid might account for the formation of the CC double bonds. It was considered that after the abstraction reaction, these double bonds react with SO3, resulting in the production of alkene sulfonic acids and sultones, along with the formation of sulfate groups as a result of reaction of the double bonds with sulfuric acid. Experimental data by treatment of the sulfonated LDPE films with KOH and thiourea supported the proposed idea, estimating the approximate molar ratio of the products. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2435–2442, 2004
Thermal properties of wood reacted with a phosphorus pentoxide–amine system
Authors: Lee Hong‐Lin , Chen George C. , Rowell Roger M.
Published: December 2003

The objective of this research was to improve the fire‐retardant properties of wood in one treatment using a phosphorus pentoxide–amine system. Phosphorus pentoxide and 16 amines including alkyl, halophenyl, and phenyl amines were compounded in N,N‐dimethylformamide and the resulting solutions containing phosphoramides were reacted with wood. The characteristics of phosphoramide‐reacted wood were analyzed by FTIR, energy‐dispersive X‐ray analysis, and elemental analysis. Fire retardancy of phosphoramide‐reacted woods was evaluated by DSC and thermogravimetric analysis (TGA). DSC demonstrated that the modification can lower the onset of an endotherm and decrease the heat of combustion and heat flow. TGA showed that most of the phosphoramide‐reacted woods had higher char yields than that of wood impregnated with diammonium phosphate.© 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2465–2481, 2004
Adsorption behavior of poly(N,N‐dimethylacrylamide‐co‐na 2‐acrylamido‐2‐methylpropanesulfonate) on sand surface
Authors: Sabhapondit Anupom , Borthakur Arun , Haque Inamul
Published: December 2003

The adsorption behavior of poly(N,N‐dimethylacrylamide‐co‐Na 2‐acrylamido‐2‐methylpropanesulfonate), an enhanced oil recovery polymer, was studied. Adsorption isotherms show that adsorption on bentonite is very high followed by that on limestone that, in turn, is much higher than that on sand surface following the order: bentonite ≫ limestone > sand. On the addition of NaCl, adsorption on sand surface decreased to a minimum value and then increased. Adsorption increased with decreasing pH and also decreasing the content of Na 2‐acrylamido‐2‐methylpropanesulfonate in the copolymer. The amount of the copolymer adsorbed on the sand surface is comparable to that of partially hydrolyzed polyacrylamide but much less than that of poly(acrylamide‐co‐vinylpyrrolidone). The type of adsorption was found to be physical, which is supported by the enthalpy of adsorption as well as by IR spectra. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2482‐2490, 2004
Preparation and structure study of polypropylene/polyamide‐6 gradient materials
Authors: Wen Bian‐Ying , Li Qing‐Chun , Hou Shao‐Hua , Wu Gang
Published: December 2003

A polymeric gradient material was prepared by a specific extruding technique in which the weight ratio of two components, polypropylene (PP) and polyamide‐6 (PA6), was changed gradually with the progress of process. This columnar gradient material was formed during a combined extruding and winding operating. The gradient variation of specimens sampled along the radius of columnar gradient material was confirmed and characterized through measurements of DSC melting behavior and elemental analysis. The morphological variation was studied using SEM observation. The results indicate that the content of either polymer shows a monotonous variation along the radius direction. With increasing radius, a gradually decreased percentage of PP was observed, whereas PA6 gradually increased. SEM photographs of the specimens sampled at different radii exhibit that the morphology also evolves gradually with variations in the percentage ratio of two polymers. A phase‐inversion phenomenon was recognized in this polymeric gradient material and a “dual mode” of dispersed morphology was found in the sandwich zone. These results indicate that the PP/PA6 blend with gradient structure was successfully prepared by use of this unique technique. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2491‐2496, 2004
Viscoelastic behavior of Cytec FM73 adhesive during cure
Authors: Hojjati Mehdi , Johnston Andrew , Hoa Suong V. , Denault Johanne
Published: December 2003

In this work, the viscoelastic properties of Cytec FM73 structural film adhesive were characterized. Several resin plates were cured using various process cycles to achieve a range of final cure states. Specimens cut from these plates were tested using a dynamic mechanical analyzer (DMA) and the glass‐transition temperature at each degree of cure was determined. Stress relaxation tests at different temperatures were then performed using DMA in stress relaxation mode and time‐temperature superposition was used to generate master stress relaxation curves and associated shift functions for each degree of cure. Several different constitutive models were examined for their ability to describe relaxation modulus development during cure. A simple three‐parameter model consisting of a stretched exponential with cure‐dependent terms was found to provide the best results. The results indicate that of the parameters used in the model, relaxation time strongly depends on cure state. The empirical DiBenedetto equation was used to obtain an expression for glass‐transition temperature as a function of degree of cure. This expression was in turn used to derive a new relation to describe stress relaxation time as a function of degree of cure. The shift function was modeled using a simplified form of the Vogel equation with cure‐dependent coefficients. Good correlation between measured relaxation modulus and model predictions was observed. © 2003 Wiley Periodicals, J Appl Polym Sci 91: 2548–2557, 2004
Complexation studies of some newly synthesized precursors for substituted dibenzo and dibenzodiaza crown ethers
Authors: Çakir Ümit , Uǧraş H. Ibrahim , Temel Hamdi , Topal Giray
Published: December 2003

This study represents the synthesis of dibenzo and dibenzodiaza crown ether precursors with various functional groups in good yield by employing four different methods using polar protic and aprotic solvents with high boiling points. Also the complexation abilities of all synthesized ligands with Cu2+, Zn2+, and Ag+ were studied by conductometry; thus the conductometric behavior of Cu(NO3)2, ZnCI2, and AgNO3 in 80% dioxane–water mixture was investigated in the presence of these ligands. The order of formation constant for complexes of the ligands with Cu2+, Zn2+, and Ag+ ions was found to be: Cu2+ > Zn2+ > Ag+ for the ligands of VI, VII, XI, and XII; Cu2+ > Ag+ > Zn2+ for the ligands of III and VIII; and Zn2+ > Cu2+ > Ag+ for the ligands of I, II, IV, V, IX, and X. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2497–2501, 2004
Notch sensitivity of aliphatic polyketone terpolymers
Authors: Zuiderduin W. C. J. , Huétink J. , Gaymans R. J.
Published: December 2003

The notch sensitivity of aliphatic polyketone (PK) terpolymers was investigated in this article. The notch‐tip radius was varied between the size of an actual propagating crack tip of 1–2 μm and the largest notch tip of 1000 μm radius. The larger notch‐tip radii (1000–15 μm) were milled into the polymer. The smallest notch‐tip radii of 2 and 15 microns were made with a novel technique with the aid of an Eximer laser. The fracture behavior of the PK‐terpolymer was found to be sensitive toward changes in notch‐tip radius. The fracture energy decreased strongly with decreasing notch‐tip radius even when fractured ductile. Sharper notches were not as effectively blunted as were larger notches in the ductile region. The brittle‐to‐ductile transition temperature (Tbd) was increased with decreasing notch‐tip radius for the larger notches (1000–100 μm). For sharper notches (2 and 15 μm) the Tbd decreased again. This behavior could be explained by the decreasing amount of elastic energy release with sharper notches. The energy release proved to be very important for this material. A mixed‐mode fracture behavior was found to occur with larger notches because of the elastic energy present in the sample before fracture. The notch sensitivity was reduced considerably by the addition of a 10% core‐shell rubber phase. For the blend material the notch‐tip radius had almost no influence on the Tbd. The fracture energy on the other hand was still lowered with a sharper notch. This was attributed to the difference in the crack initiation process. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2558–2575, 2004
Kinetics of heterogeneous polymerization of vinylidene chloride. II. Discussion of model
Authors: Lu Qun , Weng Zhi‐Xue , Huang Zhi‐Ming , Cao Xiao‐Hua , Pan Zu‐Ren
Published: December 2003

In the present article, the kinetic model for vinylidene chloride polymerization obtained in the previous article was analyzed and simplified. A series of kinetic experiments was carried out in stainless‐steel batch reactors to evaluate the model. The kinetic parameters were estimated by using these experimental data. The theoretical model prediction was compared with the experimental data. The result shows that the present model is in good agreement with experimental data over nearly the entire conversion range. © 2003 Wiley Periodicals, Inc. J Apply Polym Sci 91: 2582‐2587, 2004
A novel method for the preparation of core‐shell nanoparticles and hollow polymer nanospheres
Authors: Yu Faquan , Liu Yanping , Zhuo Renxi
Published: December 2003

A one‐step method to prepare core‐shell nanoparticles and thus hollow nanospheres is reported. The process for the formation of core and shell took place during reaction. Once the core formed, it was covered with the shell substance produced in situ, and thus, the shell hindered the continued growth of the core. Based on this method, we readily obtained core‐shell nanoparticles by choosing AgCl, CuS, or Fe(III) diethyldithiocarbamate (FeDEC)3 as model core substances and the cogel from gelatin and gum arabic as the shell substance. High‐resolution transmission electron microscopy (HRTEM) directly revealed the core‐shell structure. TEM results showed the average particle sizes were under 100 nm, depending on the core substance and the concentration of substances producing cores. After removal of the core materials, hollow nanospheres resulted, which were directly observed by TEM. The observation further verified the core‐shell structure. UV spectrophotometry also gave signals of coated structure and revealed high core content (51.1%) and nearly perfect coating (91.6%). © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2594–2600, 2004
Cationized nylon as adsorbent for anionic residual dyes
Authors: Baouab Mohamed Hassen V , Zghida Haïfa , Gauthier Robert , Gauthier Hélène
Published: December 2003

For use as an ion exchanger, a cationized nylon (EPTMAC–nylon) was prepared by reacting nylon‐6,6 with epoxy propyl trimethyl ammonium chloride (EPTMAC), using anhydrous tin chloride (SnCl2) as catalyst in a nonaqueous medium. Evidence of grafting was provided by atomic force microscopy and the exchange capacity of EPTMAC–nylon was evaluated by potentiometric titration. The adsorption of four dyes (Acid Blue 25, Acid Yellow 99, Reactive Yellow 23, and Acid Blue 74) from aqueous solutions using a batch process was studied according to the adsorption capacity of the cationized support. The effect of experimental parameters such as dye concentration and adsorption temperature were analyzed. The adsorption isotherms were determined at different temperatures and modeled using Langmuir, Freundlich, and Jossens equations. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2513–2522, 2004
Characteristics of azo‐dye binding sites on wool‐fiber keratin
Authors: Pielesz Anna
Published: December 2003

Protein electrophoresis in polyacrylamide gel in the presence of sodium dodecyl sulfate is a widely used technique for the analysis of proteins. This article presents research on the binding of model azo‐dyes, based on nongenotoxic benzidine analogs, with wool‐fiber keratin. Protein fractionation, performed by sodium dodecyl sulfate polyacrylamide gel electrophoresis and depending on the protein weight, was conducted on whole wool fibers, on fibers descaled in formic acid, and on lyophilized formic acid extracts. Dyes were bound with the proteins from the high‐sulfur‐protein area or high‐tyrosine‐protein area, depending on the level of dye dissolution. Fluorescence microscopy and transmission electron microscopy were used to illustrate the extent of the penetration of the model azo‐dyes into the wool fibers. Scanning electron microscopy was used to detect changes in the fiber topography resulting from the chemical treatments. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2629–2641, 2004
Structural control and properties of low‐dielectric‐constant poly(hydrogen silsesquioxane) precursors and their thin films
Authors: Liu Wei‐Chih , Yu Yang‐Yen , Chen Wen‐Chang
Published: December 2003

The precursors of poly(hydrogen silsesquioxane) (PHSSQ) were synthesized from triethoxysilane (TES) through variations in the pH and molar ratio of water to TES (R1). The molecular structures of the prepared PHSSQ precursors were controlled by the reaction conditions, including the molecular weight, the content of SiOH end groups, and the cage/network ratio. The effect of the reaction conditions on the PHSSQ structure was quite different from that previously reported for poly(methyl silsesquioxane) (PMSSQ). The SiOH content and cage/network ratio of the prepared PHSSQ precursors increased with increasing R1 and pH. The molecular weight of the prepared PHSSQ precursors first increased with increasing R1 or pH and then decreased at high values of R1. These results were explained by the effects of R1 and pH on the hydrolysis and condensation reactions. The cage/network ratio of the prepared PHSSQ films decreased with increasing curing temperatures and resulted in an increasing refractive index or dielectric constant. The steric effect from the side groups yielded PMSSQ films that had a smaller refractive index or dielectric constant than the PHSSQ precursors. PHSSQ films have potential applications as low‐dielectric‐constant materials. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2653–2660, 2004
Microencapsulation of capsaicin by the complex coacervation of gelatin, acacia and tannins
Authors: Xing Fubao , Cheng Guoxiang , Yang Bingxing , Ma Linrong
Published: December 2003

With gelatin and acacia as walls and capsaicin as the core substance, microcapsules were prepared through the mixing of two solutions of oppositely charged polymers and were then treated with tannins. The processing factors included the stirring rate and the types and dosages of the surfactants used in the preparation of the microcapsules. The morphology and size distribution of the microcapsules were analyzed with optical microscopy, environmental scanning electron microscopy, and laser particle size analysis. The microcapsules had a mean diameter of 20–30 μm, a maximal drug loading content of 19.84%, and an encapsulation efficiency of 88.21% with a good dispersion, even distribution, and round shape. The influence of the tannins on the morphology and structures of the microcapsules was also investigated, and their interaction mechanism was examined. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2669–2675, 2004
Composition, tensile properties, and dispersion of polypropylene composites reinforced with viscose fibers
Authors: Paunikallio T. , Suvanto M. , Pakkanen T. T.
Published: December 2003

The reinforcement mechanics of viscose‐fiber‐reinforced polypropylene (PP) composites were studied. The effect of the coupling agent, maleated polypropylene (MAPP), was of special interest. The fibers, coupling agent, and PP were extruded and injection‐molded. The composition, mechanical properties, fracture morphology, and dispersion of the composites were examined. Thermogravimetric analysis showed that the fiber content in the tensile specimens varied slightly with the sample location; however, the differences in the values were within 1.0%. Scanning electron microscopy images of the fracture surfaces of the composites showed that the surfaces of the composites without MAPP were covered with fibers pulled out from the matrix. A lack of adhesion further appeared as a cracked matrix–fiber interface. A new scanning thermal microscopy method, microthermal analysis, was used to study the dispersion of the fibers in the composites. Local thermal analyses gave further information about the location of the fibers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2676–2684, 2004
Volumetric study of aqueous solutions of poly(ethylene glycol) from 283.15 to 313.15 K and at 0.1 MPa
Authors: Cruz Raphael Da C. , Martins Rosana J. , Cardoso Márcio J. E. De M. , Barcia Oswaldo E.
Published: December 2003

Density measurements of binary aqueous solutions of poly(ethylene glycol), with a nominal average molecular weight of 6000, were used to determine the specific volumes of the solutions with solute‐to‐solvent mass ratios (mass of the solute/mass of the solvent) of 0.0483–0.5493 and at seven different temperatures (283.15, 285.15, 293.15, 298.15, 303.15, 308.15, and 313.15 K). The difference between the specific volume of a solution and the specific volume of a pure solvent, at a given temperature, was expanded by a virial‐type equation, in terms of the solute concentration. The first‐order coefficient was the partial specific volume of a solute at infinite dilution. The higher order coefficients corresponded to the contribution of pairs, triplets, and higher order solute aggregates according to the constant‐pressure theory of solutions. The functional dependence of the virial coefficients on the temperature was examined in terms of solute–solute and solute–solvent interactions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2685–2689, 2004
An analysis of the influence of the accelerator/sulfur ratio in the cure reaction and the uniaxial stress–strain behavior of SBR
Authors: Marzocca A. J. , Goyanes S.
Published: December 2003

Vulcanized styrene butadiene rubber (SBR) with different cure systems was prepared and analyzed by using the model of rubber elasticity based on the tube concept, applied to the treatment of the stress–strain measurements. Samples with several ratio accelerators to sulfur, Λ, between 0.22 and 3.0 cured at 433 K were studied. The network chain density and the crosslink density of the samples were evaluated. By means of normalized rheometer curves, the kinetics of cure of these samples were evaluated by considering the model of isothermal curing proposed by Kamal and Sourour. In this frame, the parameters of the kinetics model were obtained. A correlation between the order of the kinetic equation, n, and the network chain density of the cure samples was established. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2601–2609, 2004
Synthesis and polymerization of the bromoacrylated plant oil triglycerides to rigid, flame‐retardant polymers
Authors: Eren Tarik , Küsefoğlu Selim H.
Published: December 2003

Simultaneous addition of bromine and acrylate to the double bonds of fatty acids in triglycerides was achieved. In the first part of the study, methyl oleate was bromoacrylated in the presence of acrylic acid and N‐bromosuccinimide as a model compound for the application of the reaction to the triglycerides. Next, soybean oil and high oleic sunflower oil were bromoacrylated by using the same procedure. The products were characterized by GC, IR, 1H‐NMR, 13C‐NMR, and mass spectrometry. The bromoacrylation yields for soybean oil and sunflower oil were 75 and 55%, respectively. A rigid thermoset polymer was prepared from the radical copolymerization of bromoacrylated soybean oil with styrene. The bromoacrylated sunflower oil–styrene copolymer showed semirigid properties. The crosslinked network structure of the copolymers was examined by their swelling behavior in different solvents. Glass‐transition temperatures were also determined and soybean oil–based polymer and sunflower oil–based polymer showed a glass transition at 55–65 and 20–30°C, respectively. The storage moduli of the soybean‐based and sunflower‐based polymers at room temperature were approximately 1.0 × 1010 and 1.1 × 108 Pa, respectively. Photopolymerization was also carried out by using 2,2‐dimethoxy‐2‐phenyl‐acetophenone as initiator. The response of the cured polymers to the thermal energy produced by a small flame was also tested by the ignition respond index method according to ASTM D 3713‐78 and was found to be 5 B at 2.00 mm. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91:2700–2710, 2004
Control of particle morphology and film structures of carboxylated poly(methyl methacrylate)/poly (n‐butylacrylate) composite latex particles
Authors: Kirsch S. , Stubbs J. , Leuninger J. , Pfau A. , Sundberg D.
Published: December 2003

Particles with a hard core of 66% poly(methyl methacrylate)/34% poly(n‐butyl acrylate) copolymer and a soft shell of pure poly(n‐butyl acrylate) were synthesized via a two‐stage emulsion polymerization process. The particle morphology and the surface structure of the dispersion films were analyzed by atomic force microscopy (AFM). The results, concerning single particle structure and the corresponding films, are correlated to macroscopic properties similar to the minimum expected from the kinetic side. The different morphologies are compared to the findings reported in a previous article, where the corresponding soft‐core/hard‐shell dispersions were analyzed (Kirsch et al. Colloid Surf A 2001, 183–185, 725). The key parameters to tailor the particle morphology are thermodynamic factors, for example: (i) the stage ratio and (ii) the phase compatibility and kinetic factors affecting the polymer chain mobility (e.g., cross‐linking and polymer glass transition temperature). In this work, we used a core material which is in the glassy state at room temperature, however, above the polymer glass temperature (Tg) at polymerization temperature. The diffusion of the second‐stage polymer chains is therefore strongly affected. From this point of view, the major influence for the current system is expected from the kinetic side. The different morphologies of the single particles are discussed qualitatively and the effects of reaction parameters and our results from previous work are compared to the results of computer simulation work and other results. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2610–2623, 2004
Evolution of peroxide‐induced thermomechanical degradation of polypropylene along the extruder
Authors: Machado A. V. , Maia J. M. , Canevarolo S. V. , Covas J. A.
Published: December 2003

An experimental study of the peroxide‐induced degradation of polypropylene in a corotating twin‐screw extruder, operating under various conditions, was reported. Runs were performed without and with peroxide in different concentrations. The evolution of the chemical reactions along the extruder was characterized by on‐line rheological measurements and by determination of the molecular weight of samples collected at the same locations. The results evidenced the relationships between peroxide concentration and processing conditions with rheological properties and molecular structure of the modified materials. The concept of chain‐scission distribution function elucidated the mechanisms involved in the thermomechanical degradation of PP, which is by chain scission and is dependent on the level of stress imposed by the screw elements, temperature, and concentration of hydrogen‐abstracting agents. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91:2711–2720, 2004
Positively charged composite nanofiltration membrane prepared by poly(N,N‐dimethylaminoethyl methacrylate)/polysulfone
Authors: Du Runhong , Zhao Jiasen
Published: December 2003

Poly(N,N‐dimethylaminoethyl methacrylate) (PDMAEMA) can be crosslinked by quaternization to develop a positively charged dense network structure. According to this mechanism, PDMAEMA/polysulfone (PSF) positively charged nanofiltration membrane was developed by interfacial crosslinking polymerization using PSF plate microfiltration membrane as support layer, PDMAEMA aqueous solution as coating solution, and p‐xylylene dichloride/n‐heptane as crosslinking agent. Technique and condition of developing membrane such as concentration of coating solution, coating time, pH value of coating solution, content of low molecular weight additive in coating solution, concentration of crosslinking agent, crosslinking time, and number of coatings were studied. FTIR, SEM, and X‐ray photoelectron spectroscopy were used to characterize the structure of membranes. This membrane had rejection to inorganic salts in water solution, the rejection rate to MgSO4 (1 g/L water solution at 0.8 MPa and 30°C) was about 90%, and permeation flux was about 10–20 L m−2 h−1. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2721–2728, 2004
Albumin enhanced morphometric image analysis in CLL
Authors: Lunning Matthew A. , Zenger Vincent E. , Dreyfuss Ricardo , Stetler‐Stevenson Maryalice , Rick Margaret E. , White Therese A. , Wilson Wyndham H. , Marti Gerald E.
Published: December 2003

BACKGROUND

The heterogeneity of lymphocytes from patients with chronic lymphocytic leukemia (CLL) and blood film artifacts make morphologic subclassification of this disease difficult.

METHODS

We reviewed paired blood films prepared from ethylene‐diamine‐tetraacetic acid (ETDA) samples with and without bovine serum albumin (BSA) from 82 CLL patients. Group 1 adhered to NCCLS specifications for the preparations of EDTA blood films. Group 2 consisted of blood films containing EDTA and a 1:12 dilution of 22% BSA. Eight patients were selected for digital photomicroscopy and statistical analysis. Approximately 100 lymphocytes from each slide were digitally captured.

RESULTS

The mean cell area ± standard error was 127.8 μm2 ± 1.42 for (n = 793) for group 1 versus 100.7 μm2 ± 1.39 (n = 831) for group 2. The nuclear area was 88.9 μm2 ± 0.85 for group 1 versus 76.4 μm2 ± 0.83 for group 2. For the nuclear transmittance, the values were 97.6 ± 0.85 for group 1 and 104.1 ± 0.83 for group 2. The nuclear:cytoplasmic ratios were 0.71 ± 0.003 for group 1 and 0.78 ± 0.003 for group 2. All differences were statistically significant (P < 0.001).

CONCLUSIONS

BSA addition results in the reduction of atypical lymphocytes and a decrease in smudge cells. BSA also decreases the lymphocyte area and nuclear area, whereas nuclear transmittance and nuclear:cytoplasmic ratio are increased. A standardized method of slide preparation would allow accurate interlaboratory comparison. The use of BSA may permit better implementation of the blood film‐based subclassification of CLL and lead to a better correlation of morphology with cytogenetics and immunophenotyping. Published 2003 Wiley‐Liss, Inc.
Perfect count: A novel approach for the single platform enumeration of absolute CD4+ T‐lymphocytes
Authors: Storie Ian , Sawle Alex , Goodfellow Karen , Whitby Liam , Granger Vivian , Ward Rosalie Y. , Peel Janet , Smart Theresa , Reilly John T. , Barnett David
Published: December 2003

BACKGROUND

The derivation of reliable CD4+ T lymphocyte counts is vital for the monitoring of disease progression and therapeutic effectiveness in HIV+ individuals. Flow cytometry has emerged as the method of choice for CD4+ T lymphocyte enumeration, with single‐platform technology, coupled with reference counting beads, fast becoming the “gold standard.” However, although single‐platform, bead‐based, sample acquisition requires the ratio of beads to cells to remain unchanged, there is no available method, until recently, to monitor this.

METHODS

Perfect Count beads have been developed to address this issue and to incorporate two bead populations, with different densities, to allow the detection of inadequate mixing. Comparison of the relative proportions of both beads with the manufacture's defined limits enables an internal QC check during sample acquisition. In this study, we have compared CD4+ T lymphocyte counts, obtained from 104 HIV+ patients, using TruCount beads with MultiSet software (defined as the predicated method) and the new Perfect Count beads, incorporating an in house sequential gating strategy.

RESULTS

We have demonstrated an excellent degree of correlation between the predicate method and the Perfect Count system (r2 = 0.9955; Bland Altman bias +27 CD4+ T lymphocytes/μl).

CONCLUSIONS

The Perfect Count system is a robust method for performing single platform absolute counts and has the added advantage of having internal QC checks. Such an approach enables the operator to identify potential problems during sample preparation, acquisition and analysis. © 2003 Wiley‐Liss, Inc.