bluuebunny/crossref_metadata_2025 huggingface dataset:
Beyond palisades: The nature and frequency of late prehistoric deliberate violent trauma in the Chickamauga Reservoir of East Tennessee
Authors: Smith Maria Ostendorf
Published: July 2003

Based on the presence of palisades and an iconography suggesting a warrior elite, warfare is presumed to be endemic in the Late Mississippian period (AD 1200–1600) of the southeastern United States. Warfare is theorized to play a vital role in the cycling of chiefdoms. However, apart from a few exemplary cases that display double‐digit frequencies, very little direct (i.e., skeletal) evidence of violent trauma has dovetailed with the archaeological presumptions of warfare. Eight sites from the Chickamauga Reservoir of east Tennessee were examined for skeletal evidence of deliberate violent trauma. Violent trauma was anticipated because these sites are in close proximity and consist of two adjacent, sociopolitically distinct, and temporally overlapping phases: Dallas (AD 1300–1600) and Mouse Creek (AD 1400–1600). In addition to small, round, nonlethal ectocranial blunt‐force trauma (BFT) on the frontal and upper parietal bones, inflicted projectile points and scalping were identified. The low total trauma frequency in the Dallas sample (3.86%, n = 259) is consistent with emerging evidence from east and west Tennessee Late Mississippian data, but significantly different from Mouse Creek (8.06%, n = 273). The proportion of nonlethal cranial BFT in the collective Chickamauga sample is large and at odds with the Tennessee River Valley comparative literature. Based on other bioarchaeological literature, this pattern suggests intragroup violence, but not face‐to‐face ritual contests. It is better explained as interpersonal conflict resolution along codified lines. This is consistent with southeastern ethnohistoric data and may explain the more frequent cranial BFT in the less stratified Mouse Creek phase, which likely would not have had an overarching civil authority. Am J Phys Anthropol, 2003. © 2003 Wiley‐Liss, Inc.
Effects of rowing on humeral strength
Authors: Weiss Elizabeth
Published: July 2003

This study used an aggregate measure of robusticity (based on humeral areal and inertial cross‐sectional components) to test the hypothesis that rowing on oceans led to more robust humeri than did rowing on rivers or not rowing at all. Results confirmed the hypothesis that male ocean‐rowers had more robust humeri than did male river‐rowers or nonrowers. However, although the females from the ocean‐rowing populations did not row, they averaged more robust humeri than did females from the non‐ocean‐rowing populations. Males averaged greater robusticity than did females. The robusticity of ocean‐rowing populations, therefore, does not seem to be due solely to bone remodeling resulting from strenuous rowing. Humeral robusticity is difficult to attribute to specific activities because, in humans, upper limbs are utilized for many activities. Some populations may have more robust humeri because certain environments require greater overall activity levels in order to survive. Am J Phys Anthropol 121:000–000, 2003. © 2003 Wiley‐Liss, Inc.
Brief Communication:Age and fractal dimensions of human sagittal and coronal sutures
Authors: Lynnerup Niels , Jacobsen Jens Christian Brings
Published: July 2003

The fractal dimensions of human sagittal and coronal sutures were calculated on 31 complete skulls from the Terry Collection. The aim was to investigate whether the fractal dimension, relying on the whole sutural length, might yield a better description of age‐related changes in sutural morphology, as opposed to other methods of quantification, which generally rely on more arbitrary scoring systems. However, the fractal dimension did not yield better age correlations than other previously described methods. At best, the results reflected the general observation that young adults below age 40 years display an age‐related development, but that it is impossible to arrive at any precise age determinations for older adults. It seems that for some individuals, suture obliteration simply does not take place, even at an advanced age, whereas for others, suture obliteration progresses rapidly. Until a better understanding of sutural biology is reached, this will render cranial sutures only marginally useful in age determination. This does not mean, however, that investigations should not be made to elucidate more unbiased methods of sutural morphology quantification. Am J Phys Anthropol 9999:000–000, 2003. © 2003 Wiley‐Liss, Inc.
Cranial variation in the Marquesas Islands
Authors: Stefan Vincent H. , Chapman Patrick M.
Published: July 2003

The Marquesas Islands have traditionally been divided into a northwestern and a southeastern group, a division which reflects language dialect differences. Additionally, archaeological studies have also suggested that differences in material culture existed between the northwestern and southeastern islands. This study examines Marquesan cranial discrete and metric traits to evaluate the level of intra‐archipelago heterogeneity, and to determine if a northwest/southeast division is evident cranially.

The data consist of 28 cranial discrete traits and 49 craniofacial measurements of prehistoric Marquesans. Male and female data are pooled for discrete trait and metric data, following aZ‐score standardization technique adjustment. The data represent three island samples: Nuku Hiva (northwest), Fatuiva (southeast), and a combined Tahuata/Hiva 'Oa (southeast). Of the 28 discrete traits, 16 are utilized in a mean measure of divergence analysis that provides scores of 0.259 for Fatuiva‐Tahuata/Hiva 'Oa, 1.850 for Nuku Hiva‐Fatuiva, and 1.491 for Nuku Hiva‐Tahuata/Hiva 'Oa. Of the 49 craniofacial measurements, 46 are utilized in RMET/NORM analyses, providing unbiased D2values of 0.0433 for Fatuiva‐Tahuata/Hiva 'Oa, 0.1328 for Nuku Hiva‐Fatuiva, and 0.0813 for Nuku Hiva‐Tahuata/Hiva 'Oa. The islands of the southeastern group are closer to each other than either was to the island of the northwestern group. When a sample from 'Ua Huka is included in the craniometric analysis, the unbiased D2values of 0.0829, 0.1175, and 0.0431 are calculated for 'Ua Huka and Nuku Hiva, and Fatuiva and Tahuata/Hiva 'Oa pairings, respectively, indicating a close similarity of 'Ua Huka to the southeastern islands.

Mean measure of divergence analysis of cranial discrete traits as well as RMET/NORM analyses of craniometric variables reveal that differences exist between the islands of the northwestern and southeastern Marquesas Islands. These results support previous research that documented linguistic and cultural differences between these regions of the archipelago. However, the results indicate that 'Ua Huka, an island traditionally included in the northwestern Marquesas Islands, has an affinity to the southeastern Marquesas Islands, possibly due to its pivotal position as a waypoint in the Marquesas Island interaction sphere. Am J Phys Anthropol, 2003. © 2003 Wiley‐Liss, Inc.
Physical aging of polymer concrete during creep
Authors: Aniskevich K. , Hristova J. , Jansons J.
Published: July 2003

The long‐term creep of polymer concrete was predicted with the structural approach and with the phenomenological model of the creep of a polymer binder (polyester resin). The physical aging of polyester resin during the previous exposure of the composite at elevated temperatures and its subsequent creep was examined. The model accounted for the deceleration of relaxation processes in the polyester resin and its shrinkage. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3427–3431, 2003
Preparation and characterization of water‐extended polyester based on recycled poly(ethylene terephthalate)
Authors: Tawfik M. E.
Published: July 2003

An unsaturated polyester resin was prepared that was based on the reaction of oligomers obtained from the depolymerization of poly(ethylene terephthalate) waste products, with both maleic anhydride and sebacic acid. The structure of the produced polyester was compared with that prepared from the reaction of dimethyl terephthalate with both maleic anhydride and sebacic acid with IR and NMR spectroscopy. Water‐extended polyester resins were prepared from these two polyesters through curing with styrene in the presence of various amounts of water with benzoyl peroxide as an initiator. The mechanical properties of the prepared water‐extended polyesters, as well as scanning electron microscopy, were investigated. The use of water‐extended polyesters based on recycled poly(ethylene terephthalate) waste for the preparation of decorative art objects and statues was investigated. Therefore, three pharaonic statues representing Tutankhamen, Nefertiti, and a black head of a cat were prepared. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3693–3699, 2003
Characterization and properties of amphiphilic block polymer based on poly(ethylene oxide) and poly(butyl acrylate)
Authors: Wang Caiqi , Zhang Guo , Zhang Zhihao , Chen Xinfang , Tang Xinyi , Tan Huimin
Published: July 2003

PEO‐b‐PBA [PEO: poly(ethylene oxide); PBA: poly(butyl acrylate)], an amphiphilic block copolymer, prepared by redox radical polymerization, was characterized by infrared and 1H nuclear magnetic resonance spectroscopy. The result revealed the existence of PEO and PBA segment in purified block copolymer. The thermal behavior of the block copolymer was determined by differential scanning calorimetry. With the introduction of PBA noncrystalline segment, the crystallinity of PEO was decreased. The emulsifying and water absorptive properties of PEO‐b‐PBA were also examined. It was found that the emulsifying volume and type were dependent on the amount of block copolymer and the PEO content in block copolymer. Under a certain range, the emulsifying volume increases with an increase of PEO content. The more the PEO content in block copolymer, the stronger the water absorptivity was. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3432–3436, 2003
Effect of inorganic salts on viscosity of acrylonitrile‐N‐vinylpyrrolidone copolymer solutions
Authors: Hou Chen , Wang Cheng‐Guo , Ying Liang , Cai Hua‐Su
Published: July 2003

Effects of inorganic salts on viscosities of dimethyl sulphoxide (DMSO) solutions of acrylonitrile(AN)/N‐vinylpyrrolidone(N‐VP) copolymer are discussed. Viscosity was determined by the rotary viscosimeter. It was shown that the solution viscosity decreases quickly with addition of KCl and NaCl and the effect of NaCl is more prominent than that of KCl. As concentration of KCl and NaCl went beyond 0.025 mol/L, the viscosity showed a trend of increase. The viscosity increased considerably with addition of FeCl3 and CuCl2. Changes in solution viscosity became less obvious with addition of ZnCl2. As temperature increased, the viscosity of the copolymer solution containing NaCl decreased most quickly and the copolymer solution consisting of FeCl3 showed the slowest decrease. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3492–3495, 2003
Properties of regenerated cellulose films plasticized with α‐monoglycerides
Authors: Xiao Chaobo , Zhang Zhenjun , Zhang Jinhua , Lu Yongshang , Zhang Lina
Published: July 2003

Regenerated cellulose (RC) films were plasticized with glycerol, glycerin α‐monobutyrate, glycerin α‐monocaproate, glycerin α‐monocaprylate, and glycerin α‐monocaprate. The structure and properties of the films were investigated by using Fourier transform IR, wide‐angle X‐ray diffraction, differential scanning calorimetry, scanning electron microscopy, and tensile tests. The experimental results showed that the addition of plasticizer enhanced the elongation at break, thermal stability, and crystallinity and lowered the tensile strength of the films. The formation of hydrogen bonds between the cellulose and plasticizers weakened the inter‐ and intra‐hydrogen bonds among cellulose molecules, leading to reduced tensile strength. These α‐monoglycerides have relatively good plasticizing effects. Compared with glycerol, the resistance against water washing of the synthesized compounds was significantly enhanced. With the increase of the carbochain length of the α‐monoglycerides, the plasticizing effect decreased but the resistance against water washing was enhanced. When the RC films were immersed in a 10% glycerin α‐monocaproate solution, the elongation at break increased to 15% and stayed at 14.8% after water washing. Glycerin α‐monocaproate might be better for plasticizing RC films than others. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3500–3505, 2003
Effect of monomer type and dangling end size on polymer network synthesis
Authors: Ward Jennifer H. , Furman Kimberly , Peppas Nicholas A.
Published: July 2003

The design of novel biomaterials for applications in biological recognition, drug delivery, or diagnostics requires a judicious choice of preparation conditions and methods for the production of well‐characterized 3‐dimensional structures, preferably by benign processes. In this work, the polymerization of poly(ethylene glycol) (PEG) methacrylates was examined by kinetic gelation modeling and kinetic analysis in order to ascertain the factors affecting the resulting structure. The kinetics of the polymerization and structure of the final polymer network are strongly affected by the length of the PEG graft chain. The propagation of the polymer chains becomes increasingly diffusion limited with the incorporation of longer PEG grafts. In addition, a more heterogeneous network consisting of numerous microgel regions is produced as the length of the PEG graft is increased. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3506–3519, 2003
Structure–property relationships of poly(urethane‐urea)s with ultralow monol content poly(propylene glycol) soft segments. III. influence of mixed soft segments of ultralow monol poly(propylene glycol), poly(tetramethylene ether glycol), and tri(propylene glycol)
Authors: O'Sickey Matthew J. , Lawrey Bruce D. , Wilkes Garth L.
Published: July 2003

Recent advances in the catalyst technology associated with the production of poly(propylene glycol) (PPG) have allowed for the fabrication of ultralow monol content PPG macrodiols (Acclaim™ polyols), which are highly bifunctional and can be produced in substantially higher molecular weights and with narrower molecular weight distributions than previously possible. These factors have enabled the preparation of higher value elastomers and may allow for the first manufacture of economically attractive PPG‐based poly(urethane‐urea) (PUU) fibers. In the past, many performance polyurethane and PUU elastomers used poly(tetramethylene ether glycol) (PTMEG) for the soft segments either alone or in combination with other macrodiols. The work presented here details the investigation of the morphological features of PUU systems with mixed soft segments of PPG, PTMEG, and a low molecular analog of PPG, tri(propylene glycol) (TPG) in an effort to ascertain the influence of structural features on the mechanical and thermal properties of the elastomers. Also of interest was whether the incorporation of PPG and TPG would either prohibit or greatly hinder the formation of strain‐induced PTMEG crystallites. It was found that, even when only 60 wt % of the soft segments consisted of PTMEG, those soft segments were still able to undergo recognizable strain‐induced crystallization as detected by wide‐angle X‐ray scattering. It was also seen that, as the ratio of PPG to PTMEG was varied, there were systematic changes in the soft segment glass transition and cold crystallization characteristics. Inclusion of PPG and TPG resulted in PTMEG's diminished ability to undergo cold and strain‐induced crystallization, as seen with differential scanning calorimetry and wide‐angle X‐ray scattering. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3520–3529, 2003
Adhesion between addition‐curable silicone elastomer and nylon using diallylbisphenol A as adhesion promoter
Authors: Kerboua Rachid
Published: July 2003

It was found that the incorporation of a small amount of 2,2′‐diallylbisphenol A in a two‐component room‐temperature vulcanizing (RTV) silicone produced excellent adhesion on nylon substrates, whereas no adhesion was observed when this additive was excluded from the formulation. The effect of the chemical structure and the functionalities of this adhesion promoter were investigated by evaluation of several other molecules bearing both allylic and phenolic groups. No adhesion improvement was observed when 2‐allyl 4‐cumylphenol or 2‐allylphenol was used as the adhesion promoter, whereas with 2‐allylbisphenol A there was good adhesion between the two surfaces. Although it is quite clear that allyl groups react with the adhesive through the hydrosilylation reaction during the cure process of the RTV material, the interaction of the phenolic group with polymer surfaces seems to be largely dependent on the steric effect, that is, the ability of the OH group to be close enough to the plastic surface to develop a strong hydrogen bond. The minimum temperature required for adhesion to occur between nylon and RTV was determined to be in the range of 50°C–60°C. This temperature corresponds to the glass‐transition temperature of the amorphous part of the nylon. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3496–3499, 2003
Effect of silane monomer on the improvement of mechanical and degradable properties of photografted jute yarn with acrylamide
Authors: Hassan M. Masudul , Islam M. Rabiul , Sawpan Moyeenuddin A. , Khan Mubarak A.
Published: July 2003

UV radiation was used to graft acrylamide (AA) to jute yarn in order to improve the mechanical properties. The physicomechanical properties of the grafted jute yarn were investigated. A series of solutions of different AA concentrations in methanol along with photoinitiator (Irgacure‐907, 2%) were prepared. The jute yarns were soaked in the solution for 30 min before radiation. The effect of irradiation time, concentration of monomer on polymer loading, and tensile properties of the jute yarn were studied. The highest polymer loading (22%) and tensile strength (95%) of the yarn were observed when the yarn was treated in 30% AA in methanol with 60 min of UV radiation. The surfaces of both treated and untreated jute were characterized by X‐ray photospectrometry, infrared spectroscopy, and environmental scanning electron microscopy, and it was observed that the AA reacted or deposited on the jute surface. A minute amount (1%) of silane monomer [3‐(trimethoxysilyl)‐propyl methacrylate] was used as an additive in the AA solution to further improve the mechanical properties of jute yarn. Better improvement was achieved by using 1% silane monomer. Water uptake, simulating weathering, and soil degradation tests of untreated and treated yarns were also performed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3530–3538, 2003
Effect of thermal aging on the biodegradation of PCL, PHB‐V, and their blends with starch in soil compost
Authors: Rosa Derval dos Santos , Rodrigues Túlio César , Graças Fassina Guedes Cristina das , Calil Maria Regina
Published: July 2003

Different proportions of starch were blended with poly(β‐hydroxybutyrate)‐co‐poly(β‐hydroxyvalerate) (PHB‐V) or poly(ε‐caprolactone) (PCL) by extrusion, and the mechanical (maximum tensile strength, elongation at break and Young's modulus) and thermal properties (by differential scanning calorimetry) were determined. The biodegradability of the blends in soil compost was also assessed after thermal aging for 192, 425, and 600 h at different temperatures. The maximum tensile strength of the PCL50 blend (containing 50% starch) was 35% lower than that of PCL and that of the PHB‐V50 blend was 60% lower than that of PHB‐V without thermal aging. PHB‐V blends were more biodegradable than PCL blends. For the blends prepared, only the biodegradation of PHB‐V25 was affected by thermal aging. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3539–3546, 2003
Thermal behavior and cured products of bis(4‐maleimidodiphenyl)methane, bis(isomaleimidodiphenyl)methane and 4,4′‐diaminodiphenyl methane mixtures
Authors: Gaina V. , Gaina C. , Paraschiv I.
Published: July 2003

The thermal behavior of mixtures of bis(4‐maleimidophenyl) (A) with bis(4‐isomaleimidophenyl)methane (C) and their mixture with 4,4′‐diaminodiphenyl methane (D) were investigated by differential scanning calorimetry. The study of the binary system A/C in different proportions led us to determine an eutectic mixture at a molar fraction of C in the range of 0.7–0.9. The ternary ACD mixtures showed themselves able to participate in three principal reactions: polyaddition, ring‐opening addition, and homopolymerization. In each mixture studied the addition of diamine changed the melting point and maximum polymerization temperatures in the sense of a general decrease. The properties of the networks were studied by thermal analysis and through evaluation of water absorption. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3547–3556, 2003
Changes in morphology and properties by grafting reaction in PP/EOR/CaCO3 ternary composites
Authors: Premphet‐Sirisinha K. , Preechachon I.
Published: July 2003

The phase morphology and mechanical properties of polypropylene (PP) composites containing ethylene–octene elastomer (EOR) and calcium carbonate (CaCO3) filler were investigated by comparing the toughening effect of unmodified EOR with EOR grafted with maleic anhydride (EOR–MA). EORs of various MA contents were prepared by free‐radical grafting of MA onto the EOR backbone using a reactive extrusion process. The composite morphology was directly explored by scanning electron microscopy technique and indirectly explored by differential scanning calorimetry and dynamic mechanical analysis. Separate dispersion of the elastomer and filler particles was achieved by using unmodified EOR. Modification of EOR by maleic anhydride grafting resulted in encapsulation of the filler particles. The mechanical properties of the composites were found to depend mainly on composite morphology and composition and, to a lesser degree, on maleic anhydride concentration. The results of this study showed that when composites contained an equal or higher amount of elastomer relative to filler, a composite with a separate dispersion structure was preferred. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3557–3562, 2003
Sonochemical polymerization of acrylic acid and acrylamide in the presence of a new redox system— A comparative study
Authors: Anbarasan R. , Jayaseharan J. , Sudha M. , Gopalan A.
Published: July 2003

Acrylic acid and acrylamide were polymerized by a peroxydisulfate–suberic acid redox system under a nitrogen atmosphere both in the presence and in the absence of ultrasound (at constant frequency). The rate of polymerization was determined for different concentrations of monomer, initiator, and activator and for different percentages of ultrasonic intensity. The polymers were characterized by X‐ray diffraction and 1H‐NMR spectroscopy. A probable mechanism is proposed to explain the experimental results obtained. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3685–3692, 2003
Radiation effects on methyl vinyl polysilicone foam
Authors: Huang Wei , Fu Yibei , Wang Chaoyang , Xu Yunshu , Chen Yinliang
Published: July 2003

The effects on methyl vinyl polysilicone foam of 60Co γ‐ray radiation at room temperature was studied in air, in vacuo, and in an inert gas atmosphere. The unirradiated and irradiated samples were analyzed by Fourier transform infrared spectroscopy, scanning electron microscopy, pyrolysis gas chromatography/mass spectroscopy, and thermogravimetric analysis, and the gas products after radiation were analyzed by gas chromatography/mass spectroscopy. The changes of the gel fraction, compression properties, and the stress–relaxation ratio with dose for irradiated samples were observed. The results show that the second crosslinking reaction in the polysilicone after chemical crosslinking took place at a low dose (2 × 105 Gy), but radiation degradation was predominant, with the dose increasing step by step. The mechanical properties of polysilicone foam gradually became low grade after it was irradiated by any dose in excess of 2 × 105 Gy. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3437–3441, 2003
Effect of hydrophobic hexafluoroisopropylidene group on the water sorption behaviors of rigid poly(p‐phenylene pyromellitimide) polyimide thin films
Authors: Seo Jongchul , Yup Lee Sang , Jang Wonbong , Han Haksoo
Published: July 2003

We prepared poly(p‐phenylene pyromellitimide) (PMDA–PDA), poly(p‐phenylene 4,4′‐hexafluoroisopropylidene diphthalimide), and their copolyimides with various compositions to explore the relationship between the water sorption and structure. The water sorption behaviors were gravimetrically investigated as a function of composition and temperature and interpreted with a Fickian diffusion model in films. Overall, the water sorption behaviors were strongly dependent on the changes in morphological structure, which originated from the variations in composition. When the content of the bulky hexafluoroisopropylidene group (6FDA) was increased, the water uptake decreased from 5.80 to 3.18 wt %, whereas the diffusion coefficient increased from 3.6 × 10−10 to 11.3 × 10−10 cm2/s. The relatively high water uptake in the PMDA–PDA polyimide film was successfully healed by the incorporation of 6FDA, which may have resulted from the increases in the intermolecular packing order and hydrophobicity. The degree of orientation and crystallinity, which are in‐plane characteristics, were directly correlated to the diffusion coefficient and activation energy in the polyimide film. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3442–3446, 2003
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

Accelerated 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

The 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

The 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

We 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

An 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

The 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

This 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

The 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

Polysiloxane 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

Styrene 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

H1 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

An 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

Four 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

A 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

A 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

A 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

Vickers 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