bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydrothermic aging of plasticized poly(vinyl chloride): Its effect on the dielectric, thermal, and mechanical properties
Authors: Djidjelli H. , Kaci M. , Boukerrou A. , Benachour D. , Martinez‐Vega J. J. 
Published: July 2003

AbstractAccelerated hydrolytic aging (according to the NFT 5166 method) was performed on samples of poly(vinyl chloride) (PVC) plasticized with dioctylphthalate (DOP) and dinonyladipate (DNA) at different concentration ratios. The aging test consisted of immersing the samples in boiling water at 100°C. The samples were removed from water regularly, that is, every 2 h, for mechanical, thermal, and dielectric characterizations. Thermograms of PVC plasticized with DOP revealed no migration of the plasticizer independent of the concentration used. Moreover, the thermal stability of the samples was not affected by the hydrothermal aging. However, for PVC samples plasticized with DNA, a small amount of the plasticizer migrated from the polymer matrix with a considerable effect on the thermal stability. In fact, the data indicated a decrease in the decomposition temperature from 275 to 225°C, particularly for samples containing 50% (w/w) DNA immersed up to 10 h. The mechanical results showed that for a plasticizer content greater than 30% (w/w), the strain at break obtained for samples plasticized with DNA was lower than that for samples plasticized with DOP because the DNA molecules were more likely to be removed by water on account of their polarity and dimension. Finally, the dielectric measurements showed that the permittivity of all the PVC samples plasticized with DOP and immersed in boiling water was higher than that of the virgin samples. On the contrary, the permittivity of the aged unplasticized PVC was less than that of the nonimmersed samples. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3447–3457, 2003
Temperature dependence of the thermal conductivity and thermal diffusivity of treated oil‐palm‐fiber‐reinforced phenolformaldehyde composites
Authors: Singh Kedar , Saxena N. S. , Sreekala M. S. , Thomas S. 
Published: July 2003

AbstractThe effective thermal conductivity (λe) and effective thermal diffusivity (χe) of oil‐palm‐fiber‐reinforced treated composites were measured simultaneously with the transient plane source technique from 50 to 110°C. The fibers of the composites were treated with sodium hydroxide alkali, silanol, and acetic acid. The experimental results for the different treated composites showed that there were variations in λe and χe over this temperature range. However, the maximum values of λe and χe were observed at 90°C, in the vicinity of the glass‐transition temperatures of these composites. An effort was also made to predict the temperature dependence of λe and χe through the development of an empirical model. The theoretically predicted values of λe and χe for these composites were in excellent agreement with the experimental results over the entire range of investigated temperatures. Sudden increases in λe and χe in the glass‐transition region of these composites were indicative of the fact that the crosslinking density decreased and was at a minimum at the temperature at which λe and χe showed their maxima. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3458–3463, 2003
Cold‐crystallization kinetics of syndiotactic polystyrene
Authors: Lu Hongbin , Nutt Steven 
Published: July 2003

AbstractThe kinetics of the isothermal and nonisothermal cold crystallization of syndiotactic polystyrene (s‐PS) were characterized with differential scanning calorimetry. A Johnson–Mehl–Avrami analysis of the isothermal experiments indicated that the cold crystallization of s‐PS at a constant temperature followed a diffusion‐controlled growth mode with a decreasing nucleation rate. Furthermore, the slow nucleation rate was the controlling step of the entire kinetic process. For nonisothermal cold‐crystallization kinetics, we used a simple model based on a combination of the well‐known Avrami and Ozawa models. The analysis revealed that, unlike for melt crystallization, the Avrami and Ozawa exponents were not equal. The activation energies for the isothermal and nonisothermal cold crystallizations of s‐PS were 792.0 and 148.62 kJ mol−1, respectively, indicating that the smaller motion units in cold crystallization had a weaker temperature dependence than those in melt crystallization. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3464–3470, 2003
Effect of crosslinking on the conductivity of conductive silicone rubber
Authors: Zhang Jie , Feng Shengyu 
Published: July 2003

AbstractWe investigated the effect of polyvinylsilicone oil (C gum) as a crosslinker and 2,5‐bis(tert‐butyl peroxy)‐2,5‐dimethyl hexane (DBPMH) as a curing agent on the conductivity of conductive silicone rubber with two different kinds of conducting mechanisms. The experimental results show that the volume resistivity of conductive silicone rubber changed with its degree of crosslinking. When the carbon black loading was 25 parts per hundred rubber (phr) and a completely continuous conducting network had not formed, the volume resistivity of the vulcanizates decreased with increasing crosslink density. The volume resistivity of the vulcanizate with a suitable amount of C gum decreased to 53%, and the tensile strength increased by 0.8 MPa compared to the vulcanizate without C gum. When the carbon black loading was 40 phr and a completely continuous conducting network had formed, the crosslink density of vulcanizates changed as the amount of DBPMH changed. The volume resistivity of vulcanizates first decreased and then increased with increasing crosslink density. There was a valley value in the resistivity–crosslink density curve. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3471–3475, 2003
Properties of chitosan‐based biopolymer films with various degrees of deacetylation and molecular weights
Authors: Hwang Kwon T. , Kim Jun T. , Jung Soon T. , Cho Gun S. , Park Hyun J. 
Published: July 2003

AbstractAn increase in the depolymerization of chitosan was found with an increased concentration of sodium perborate. Acetic anhydride was added to reacetylated chitosan in a molar ratio per gulcosamine unit, and the amide I band of IR spectra changed with the addition of acetic anhydride. Sixteen chitosans with various molecular weights (MWs) and degrees of deacetylation (DODs) were prepared. X‐ray diffraction patterns indicated their amorphous and partially crystalline states. Increases in the chitosan MW and DOD increased the tensile strength (TS). TS of the chitosan films ranged from 22 to 61 MPa. However, the elongation (E) of chitosan films did not show any difference with MW. TS of chitosan films decreased with the reacetylation process. However, E of chitosan films was not dependent on DOD. The water vapor permeabilities (WVPs) of the chitosan films without a plasticizer were between 0.155 and 0.214 ng m/m2 s Pa. As the chitosan MW increased, the chitosan film WVP increased, but the values were not significantly different. Moreover, the WVP values were not different from low DOD to high DOD. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3476–3484, 2003
Exhaust dyeing of polyester‐based textiles using high‐temperature–alkaline conditions
Authors: Ibrahim N. A. , Youssef M. A. , Helal M. H. , Shaaban M. F. 
Published: July 2003

AbstractThe factors affecting the dyeability of polyester‐based textiles with disperse dyes in an alkaline medium were studied. It was found, for a given set of dyeing conditions, that (a) the appropriate conditions for attaining a higher color yield were 45 min at 130°C with pH 9 using a material‐to‐liquor ratio of 1/10; (b) increasing the Diaserver® AD‐95 concentration to 2% ows (based on weight of substrate) as well as including triethanolamine to 2% ows in the dyeing formulations bring about a significant improvement in the dye uptake; (c) both a preheat setting from 160 to 200°C/30 s and an alkaline weight reduction have a positive impact on postdyeing with the used disperse dye; (d) the extent of dye uptake as well as the color strength are governed by the type of substrate, that is, knitted fabric > spun yarn > woven fabric, nature of the dye stabilizer, that is, EDTA > Diaserver® AD‐95 > Tinoclorite® CBB > citric acid > none, as well as kind of the disperse dye; (e) direct reuse of the disperse dyebaths, without reconstitution, in the dyeing of the used substrates was shown to be feasible in a single shade and in the reverse‐order dyeings (dark → light); (f) one‐bath, one‐step exhaust dyeing of polyester/cotton‐knitted fabric using selected disperse reactive dyes combinations under high‐temperature alkaline conditions is feasible; and (g) the color and fastness properties of the resultant dyeings depend on the type of the used auxiliaries, in addition to the nature of disperse/reactive dyes combinations as well as compatibility with other ingredients. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3563–3573, 2003
Retention and reusability of trypsin activity by covalent immobilization onto grafted polyethylene plates
Authors: Yamada Kazunori , Nakasone Toshiaki , Nagano Ryoichi , Hirata Mitsuo 
Published: July 2003

AbstractThis study investigated the activity of trypsin that had been covalently immobilized onto acrylic acid (AA)– and methacrylic acid (MAA)–grafted polyethylene (PE) plates—PE–g–PAA and PE–g–PMAA—using a water‐soluble carbodiimide as a coupling agent, as a function of the immobilized amount, the grafted amount, the pH value on immobilization, and the pH value and temperature at the activity measurement. The activity of trypsin immobilized on the PE–g–PAA plates at pH 6.0 decreased with an increase in the immobilized amount because of the crowding of trypsin molecules in the vicinity of the surfaces of the grafted PAA layers. The increase in the grafted amount resulted in a decrease in the activity of immobilized trypsin because of a decrease in the diffusivity of BANA molecules caused by the formation of dense grafted PAA layers for the PE–g–PAA plates and led to the increased activity because of the increase in the hydrophilicity of the whole grafted layers for the PE–g–PMAA plates. The activity of trypsin immobilized on the PE–g–PAA and PE–g–PMAA plates at pH 6 increased with an increase in the pH value, probably because of the expansion of trypsin‐carrying grafted PAA and PMAA chains and the increased diffusivity of Nα‐benzoyl‐DL‐arginine‐nitroanilide hydrochloride molecules in the grafted layers. The optimum temperature of the activity of immobilized trypsin shifted to 50°C from 30°C for native trypsin. Immobilized trypsin was reusable without any denaturation and isolation at temperatures ranging from 20°C to 60°C and pH values ranging from 6 to 10. Trypsin immobilized on a PE–g–PAA plate had 95% of the remaining activity in relation to native trypsin at 30°C after preservation in a pH 7.8 buffer at 4°C over 6 months. These results made clear that alkaline and thermal stability, reusability, and storage stability can be much improved by the covalent coupling of trypsin on PE–g–PAA and PE–g–PMAA plates. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3574–3581, 2003
Determination of the formaldehyde‐to‐phenol molar ratios of resol resins by infrared spectroscopy and multivariate analysis
Authors: Holopainen Hilkka , Alvila Leila , Pakkanen Tuula T. , Rainio Jouni 
Published: July 2003

AbstractThe formaldehyde/phenol (F/P) ratios of resol resins were successfully predicted by the recording of infrared (IR) spectra of both calibration and analyzed resins and by a multivariate analysis technique. In the creation of applicable models, the best correlating IR spectral areas were found between 1800 and 700 cm−1. The positive effects of the increasing replicates and the omission of first‐derivative preprocessing on model quality were proven by systematic testing. The characteristic statistical parameters were acceptable when the resin was similar to the calibration resins. Although the calibration samples had narrow F/P molar ratios (2.00–2.40), or a particular urea content or alkalinity, the best calibration model could also successfully predict the F/P molar ratios of resins with greater F/P ratios, higher urea contents, and lower alkalinity. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3582–3586, 2003
Microemulsion polymerization of siloxane with nonionic surfactants as emulsifiers
Authors: Zhang Dunming , Jiang Xiqun , Yang Changzheng 
Published: July 2003

AbstractPolysiloxane nanolatices were prepared by the microemulsion polymerization of octamethylcyclotetrasiloxane (D4) with nonionic polyoxyethylene alkyl ether and polyoxyethylene aryl ether as surfactants, ethylene glycol or aminoethanol as a cosurfactant, and potassium hydroxide or dipotassium dimethylsilanolate (I) as an initiator. The effect of the different initiators and the amount of cosurfactant on the microemulsion polymerization rate of D4 was investigated. The initiator, potassium hydroxide, had a similar catalytic activity to I, and adding the cosurfactant changed a common siloxane emulsion to a microemulsion. At a same reaction conditions, the polymerization rate of D4 with aminoethanol as a cosurfactant was much faster than that of ethylene glycol. The kinetics of this siloxane microemulsion polymerization was consistent with Morgen‐Kaler theory. The transparency value of the resultant polysiloxane nanolatex was more than 95% when the amount of ethylene glycol was more than 25% and the siloxane amount was about 30 wt % of the reaction mixture. A nanolatex of polydimethylsiloxane‐co‐polyvinylmethylsiloxane, which was crosslinked with potassium persulfate, revealed that the mean diameter of the droplets was 32 nm with a narrow distribution. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3587–3593, 2003
Behavior of nonazeotropic compositions of a styrene–unsaturated polyester resin analyzed through FTIR spectroscopy and dynamic mechanical thermal analysis
Authors: Marroyo L. M. , Ramis X. , Salla J. M. 
Published: July 2003

AbstractStyrene is one of the comonomers most frequently used in the curing of unsaturated polyester resins. The use of nonazeotropic compositions leads to the formation of networks, in which the styrene–polyester ratio varies significantly during curing, as shown through FTIR spectroscopy. Dynamic mechanical thermal analysis (DMTA) showed how the variation in the styrene content affects the network structure that is formed. The results showed a decrease in network density in the systems in which the azeotropic composition was not used. The styrene content is therefore a factor that governs the curing process, in addition to the ultimate properties of the cured resins. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3618–3625, 2003
Study of needle penetration speeds on frictional properties of nonwoven webs: A new approach
Authors: Ramkumar S. S. , Roedel C. 
Published: July 2003

AbstractH1 technology needlepunching machinery is one of the recent developments in the needleloom technology. H1 technology needlepunching nonwoven machinery has been effectively utilized to develop a set of nonwoven substrates at different punching rates. The effect of needlepunching speeds on the frictional properties of H1 technology polyester nonwoven webs is reported in this article. The frictional properties of nonwoven webs have been characterized using a simple normalized friction factor. In addition, the surfaces of the nonwoven substrates were scanned using scanning electron microscopy. The results show that for the three different penetration rates studied there seems to be a marginal difference in the frictional properties. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3626–3631, 2003
Dehydration of water–alcohol mixtures by vapor permeation through PVA/clay nanocomposite membrane
Authors: Yeh Jui‐Ming , Yu Ming‐Yao , Liou Shir‐Joe 
Published: July 2003

AbstractAn organic/inorganic hybrid nanocomposite membrane, poly(vinyl alcohol)/clay (PVAC), was prepared. The morphology of PVAC nanocomposite membranes were characterized using transmission electron microscopy (TEM), X‐ray diffraction (XRD), and atomic force microscopy (AFM). The crystallinity and surface roughness increases with an increasing clay content in the PVAC nanocomposite membrane. Compared with the pure poly(vinyl alcohol) (PVA) membrane, the hybrid nanocomposite membrane (PVAC) shows an improvement in the thermal stability and the prevention of the water‐soluble property. The oxygen permeability and the water‐vapor permeation rate decreases with an increasing clay content (1–3 wt %) in the PVAC nanocomposite membranes. In addition, the effects of the clay content on the vapor‐permeation performance of an aqueous ethanol solution through the PVAC nanocomposite membranes was also investigated. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3632–3638, 2003
Blending of poly(lactic acid) and starches containing varying amylose content
Authors: Ke Tianyi , Sun Susan Xiuzhi , Seib Paul 
Published: July 2003

AbstractFour dry corn starches with different amylose content were blended at 185°C with poly(lactic acid) (PLA) at various starch:PLA ratios using a lab‐scale twin‐screw extruder. Starch with 30% moisture content also was blended with PLA at a 1:1 ratio. Each extrudate was ground and dried. The powder was mixed with about 7.5% plasticizer, and injection molded (175°C) into test tensile bars. These were characterized for morphology, mechanical properties, and water absorption. Starch performed as a filler in the PLA continuous matrix phase, but the PLA phase became discontinuous as starch content increased beyond 60%. Tensile strength and elongation of the blends decreased as starch content increased, but no significant difference was observed among the four starches at the same ratio of starch:PLA. The rate and extent of water absorption of starch/PLA blends increased with increasing starch. Blends made with high‐amylose starches had lower water absorption than the blends with normal and waxy corn starches. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3639–3646, 2003
Influence of properties and morphology of elastomeric phase on the behavior of ternary reactive blends of polyamide 6/rigid polymer/elastomer
Authors: Kelnar I. , Kotek J. , Munteanu B. S. , Fortelný I. 
Published: July 2003

AbstractA ternary blend of the PA6 matrix with a finely dispersed rigid polymer and elastomer is a system with well‐balanced mechanical properties. Its micromechanical behavior, especially that of the elastomer phase, apparently differs from corresponding binary mixtures. This study shows the influence of the elastomer type, modulus, and reactivity on the behavior of ternary blends in comparison with analogous binary PA6/elastomer combinations. The presence of rigid reactive poly(styrene‐co‐maleic anhydride) (SMA) enhanced the properties of all the systems studied. For nonreactive elastomers, the dominant effect was refinement of their size due to enhanced viscosity, whereas for functionalized low‐modulus elastomers, the very good balance of properties was due to synergistic influences of both finely dispersed phases. Of interest is the enhanced toughness of ternary blends also for more rigid elastomers having a low toughening efficiency in binary blends. An appropriate addition of rigid SMA together with an elastomer enhances the energy absorption of the matrix, probably without cavitation of very small elastomer particles. Of importance also is the simultaneous strain‐hardening effect of deformed rigid particles. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3647–3651, 2003
Effect of montmorillonite on the swelling behavior and drug‐release behavior of nanocomposite hydrogels
Authors: Lee Wen‐Fu , Fu Yao‐Tsung 
Published: July 2003

AbstractA series of nanocomposite hydrogels were prepared from various ratios of N‐isopropylacrylamide (NIPAAm) and organic montmorillonite (MMT). The influence of the extent of MMT in the NIPAAm/MMT nanocomposite hydrogels on the physical properties and drug‐release behavior was the main purpose of this study. The microstructure and morphology were identified by X‐ray diffraction (XRD) and scanning electronic microscopy (SEM). The results showed that the swelling ratios for these nanocomposite hydrogels decreased with increase in the content of MMT. The gel strength and Young's modulus of the gels also increased with increase in the content of MMT. XRD results indicated that the exfoliation of MMT was achieved in the swollen state. Finally, the drug‐release behavior for the gels was also assessed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3652–3660, 2003
Hydrogenation catalysis of nanosized palladium supported by polymer/silica disupporter. II. Effects of the characteristics of the catalyst on hydrogenation
Authors: Liu Yinfeng , Huang Aiming , Chen Jing , Chen Lai , Hua Jiadong 
Published: July 2003

AbstractA series of nanosized palladium catalysts supported by silica and polymers, prepared by the complex transformation method, were used for catalytic hydrogenation of nitrobenzene. It was found that both the thickness of the polymer layer and the size of the palladium particles would affect the catalysis. The results indicated that the reaction rate would be optimal when a polymer supporter formed a single layer on the silica surface. The catalytic activity of the catalyst would not simply increase with the decrease of the size of palladium particles. The effects of other conditions on the catalytic properties, such as the order during preparation of the catalyst, solvent, and the pH values, were also discussed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3661–3665, 2003
Glass‐transition temperature determination by microhardness in norbornene‐ethylene copolymers
Authors: Benavente Rosario , Scrivani Teresa , Cerrada Maria L. , Zamfirova Galina , Pérez Ernesto , Pereña José M. 
Published: July 2003

AbstractVickers microhardness as a function of temperature was determined in a series of norbornene‐ethylene copolymers synthesized with a metallocene catalyst. The norbornene content in the samples ranges from 31 to 62 mol %, and all of them were found to be amorphous. The possibility of studying the glass‐transition temperature by plotting the microhardness‐temperature dependencies is discussed in addition to the limits and the reliability of the suggested method. Moreover, a linear dependency between microhardness at different temperatures and glass‐transition temperature was established. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3666–3671, 2003
Influence of solvent contents on the rubber‐phase particle size distribution of high‐impact polystyrene
Authors: Lee Seong Jae , Jeoung Han Gyun , Ahn Kyung Hyun 
Published: July 2003

AbstractHigh‐impact polystyrene (HIPS) was prepared by the bulk or low‐solvent polymerization of styrene in the presence of dissolved rubber and characterized to measure the dispersed particle size of the rubber phase. Before preparation, the prepolymerization time was established by measuring the evolution of particle size distribution of the dispersed phase as a function of reaction time. The measurement technique by laser light scattering was found to be efficient enough not only to lead to the right prepolymerization time but also to predict rubber‐phase particle size distribution. Polymerization experiments were then conducted to investigate the effect of solvent contents on the particle size distribution of the rubber phase, in which ethylbenzene was introduced as a solvent at levels of 0, 3, 10, and 15%. As the solvent content increased, the size of rubber‐phase particles initially increased, reaching a maximum, and then decreased. It is speculated that a decrease in the molecular weight of the matrix, a decrease in the viscosity ratio between polybutadiene to polystyrene phases, and a change in rubber morphology all contributed to the change in the rubber particle size of HIPS. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3672–3679, 2003