bluuebunny/crossref_metadata_2025 huggingface dataset:
Recycling, Oil
Authors: Brinkman Dennis W. , Parry Barbara J.
Published: May 2005

This article discusses the recycling of used petroleum oils, especially those employed as lubricants. The term oil includes a variety of liquid or easily liquefiable, unctuous, combustible substances that are soluble in ether, but not in water, and that leave a greasy stain on paper or cloth. These substances can include animal, vegetable, and synthetic oils, but usually the word oil refers to a mineral oil produced from petroleum. An oil that has been used or contaminated, or both, but not consumed, can often be recycled to regain a useful material regardless of its origin. In the past, used or contaminated oil was often considered a waste and was disposed of in a variety of ways, including incineration, road oiling, landspreading, municipal landfills, and dumping on the ground or into storm sewers. However, growing public awareness of the societal costs of pollution, the advent of periodic petroleum shortages, and increased prices for most kinds of oils and oil products have combined to generate a strong interest in developing ways to conserve the valuable energy and resource content of these products.
Perchloric Acid and Perchlorates
Authors: Mendiratta Sudhir K. , Dotson Ronald L. , Brooker Robert T. ,   Updated by Staff
Published: May 2005

Perchlorates are chlorine oxyanions in which the chlorine is present in its highest oxidation state (+7). The most outstanding property of the perchlorates, which are more stable than other chlorine oxyanions, is their oxidizing ability. Most cations form perchlorate compounds. Commercially, one of the most important compounds of this class is ammonium perchlorate, used as an oxidizer in propellant formulations for solid rocket fuel. Perchlorates are also used in explosives and pyrotechnics, in dry batteries, and in oxygen‐generation systems. Commercial perchlorates are prepared by electrochemical oxidation. Perchloric acid, commercially available as a 72% aqueous solution, is one of the strongest of the mineral acids. Properties, manufacturing, and uses of these compounds are described.
Phenol
Authors: Wallace Jim ,   Updated by Staff
Published: May 2005

Phenol (hydroxybenzene) is a commercially important derivative of benzene. It is the primary feedstock for the production of epoxy resins and polycarbonates, phenolic resins and molding compounds, caprolactam, aniline, and other chemical derivatives.

More than 95% of the phenol consumed is produced by the cumene peroxidation process. Phenol is a white, crystalline mass at room temperature. Its freezing point is 40.91°C. It is a protoplasmic poison that is corrosive to living tissue and is readily absorbed through the skin.

Phenol’s consumption growth rate is based primarily on its use in engineering plastics such as bisphenol A, polycarbonates, polyetherimide and poly(phenylene oxide), and epoxy resins for the electronics industry. Due to the nature of its end markets, phenol consumption is highly cyclic. Future production processes for phenol will be affected by the disparity in growth rate between phenol and its coproduct, acetone.
Pyrolysis, Flash Vacuum
Authors: McNab Hamish
Published: May 2005

The use of the technique of flash vacuum pyrolysis (FVP) in mechanistic and synthetic organic chemistry is reviewed. The design of typical apparatus and typical reactions used in FVP experiments are discussed. Examples of protocols for mechanistic studies and the investigation of reactive intermediates (use of isotopic labeling, gas‐phase analytical methods, and matrix isolation) are given. The synthetic applications of FVP are considered with respect to the new bond(s) generated in the pyrolysis step, namely, alkanes, alkenes, alkynes, aromatics, heteroatom‐containing functional groups, and heterocycles.
High Pressure Chemistry
Authors: Hubbard Colin D. , van Eldik Rudi
Published: May 2005

The technology associated with application of hydrostatic pressure in chemistry is presented. Apparatus and equipment range from a straightforward autoclave‐type arrangement to more sophisticated techniques of subjecting materials or chemical reactions in solution to pressure, and monitoring events caused by pressure application while the system is under pressure (ie,in situ). Spectroscopic detection is the principal monitoring technique inin situmethods. The wide span of time ranges of changes taking place during a pressure cycle requires different types of technologies and these are described. The type of system under investigation directs the choice of method and the range of pressure applied. For synthetic and preparative solution chemistry, pressures up to a few thousand megapascals (MPa) have been used. For processing of materials to bring about a change in properties, pressures up to 600 MPa are usually adequate, whereas for most mechanistic studies pressures > 200 MPa are rarely used (1 atm = 1.01325 × 105Pa; 1 Pa = 1 N/m2). Examples of systems studied from organic chemistry, inorganic chemistry, bioinorganic chemistry, and colloid chemistry are provided. These clearly illustrate the value of applying hydrostatic pressure and demonstrate insight into understanding physicochemical and chemical changes that occur. Such insight is not normally achievable by other experimental approaches and highlights the unique value and success of high pressure technology in chemistry.
Pharmaceuticals, Large‐Scale Synthesis
Authors: Gupton B. Frank , Grozinger Karl
Published: May 2005

The capability to fulfill drug substance requirements in support of the various elements of pharmaceutical development is an essential component of the overall drug development process. The preparation of bulk materials for toxicology, formulation development, and clinical supplies can represent a significant challenge, depending on such factors as the molecular complexity of the drug candidate, the quantities of materials required, and the state of development of the synthetic process. As a drug candidate proceeds through the various stages of drug development and into commercial launch, the challenge of process development is to ensure the uninterrupted supply of drug substance without compromising the ability to ultimately supply a commercially viable chemical process. This chapter serves to provide a general overview of the issues and requirements associated with the development and scale‐up of chemical processes for bulk active drug substances. An account of the nevirapine process development efforts at Boehringer Ingelheim is also provided as an example of the evolution of a chemical process from the initial efforts in medicinal chemistry through to commercial‐scale operations.
Where are Learning Communities? Now: National Leaders Take Stock
Authors: Macgregor Jean , Smith Barbara Leigh
Published: May 2005

A multiyear effort to understand and improve the practice of learning communities across North America has revealed encouraging trends and areas in which work should continue. The authors asked nearly sixty educators involved in the work to write and talk about the state of learning communities.
Beyond Magical Thinking: Doing the Real Work of Diversifying Our Institutions
Authors: Chang Mitchell J. , Chang June C. , Ledesma María C.
Published: May 2005

U.S. Supreme Court opinions have left some doors open for institutions to build the kinds of diverse student populations that are known to enrich the learning of all students. But simply inviting diverse students through those doors is not doing nearly enough.
Distance Learners: Welcome to Campus!
Authors: Schwitzer Alan M. “Woody” , Duggan Mary H.“Molly”
Published: May 2005

When Old Dominion University created a summer institute to allow adult distance learning students to enroll in accelerated on-campus courses, typical college transition issues were, at first, left off the schedule. Over the years, the institute has evolved to provide these students with the same kind of personal and academic support needed by their traditional-age peers.
Who are Our Students?
Authors: Onge Stephen R. St. , Ellett Thomas
Published: May 2005

On the importance of understanding today's adolescents
Noncognitive Assessment
Authors: Wawrzynski Matthew
Published: May 2005

Toward more accurate predictions of student success
Ethnic expansions and between‐group differences in children's health: A case study from the Rukwa Valley, Tanzania
Authors: Hadley Craig
Published: May 2005

The Sukuma ethnic group appears to be expanding across Tanzania at a rate far greater than other ethnic groups in the area. In this paper, the household‐level dynamics that may be fueling this expansion are explored by comparing measures of infant mortality and child health with another Tanzanian ethnic group, the Pimbwe. Consistent with expectations, the Sukuma appear to have comparable levels of fertility but lower child mortality. As predicted, compared to the Pimbwe, Sukuma children are also heavier and taller for their age, suggesting better nutritional status. Four hypotheses about why the Sukuma are so successful in this area are addressed. Surprisingly, the results show that household food security and wealth are not related to children's nutritional status, nor can maternal effects account for the observed health differences. Several lines of evidence suggest that different patterns of infant feeding practices may underlie the differences in children's nutritional status. Am J Phys Anthropol, 2005. © 2005 Wiley‐Liss, Inc.
Growth and nutritional status of male adolescent laborers in Ankara, Turkey
Authors: Duyar İzzet , Özener Barış
Published: May 2005

Undernutrition, pathogenic agents, and poor living conditions are of primary importance in the evaluation of adverse environmental conditions' effects on human growth; but child labor (an equally significant factor, especially in underdeveloped countries) is generally overlooked or ignored. The aim of this study is to focus on this subject and clarify the effects of labor on the physical growth and nutritional status of child and adolescent laborers. In this study, the height and weight of 532 male adolescent laborers aged 13.5–18.5 years and their nonlaboring peers (n = 451) (the control group) were measured by standard anthropometric techniques and equipment. The individuals of both groups come from lower socioeconomic strata and share similar living conditions. Data were transformed to z‐scores, using the US Center for Disease Control and Prevention's 2000 growth charts. The analyses show that the z‐scores for height‐for‐age, weight‐for‐age, and body mass index (BMI)‐for‐age were negative in both groups. The z‐scores of laborers' height‐for‐age and weight‐for‐age values lie below the controls', but there is no significant difference between the two groups' BMI‐for‐age scores. In the laboring group, the percentages of stunting (−2 SD of height‐for‐age), underweight (−2 SD of weight‐for‐age), and wasting (−2 SD of BMI‐for‐age) were 14.3, 2.6, and 0.2, respectively. These values suggest that malnutrition is not a common problem among adolescent laborers living in Ankara; but laboring is an important cause of faltering in growth, particularly in linear growth, in less or underdeveloped economic environments. Am J Phys Anthropol, 2005. © 2005 Wiley‐Liss, Inc.
Dental caries among the prehispanic population from Gran Canaria
Authors: Delgado‐Darias T. , Velasco‐Vázquez J. , Arnay‐de‐la‐Rosa M. , Martín‐Rodríguez E. , González‐Reimers E.
Published: May 2005

The island of Gran Canaria was inhabited in pre‐Hispanic times by people of North African origin who arrived on the island towards the second half of the first millennium BC. In previous studies, we reported that there are some differences between the coastal inhabitants from Gran Canaria, mainly buried in tumuli, and those from the central mountains, mainly buried in caves. For example, the prevalence of auricular exostoses is higher among the population interred in coastal tumuli when compared with the inland population. This finding may be explained by the practice of marine activities, as supported by chroniclers' reports, by archaeological data, and by bone trace‐element analysis, which point to a more intense consumption of marine products by the inhabitants of the coastal regions. Dental caries epidemiology is one of the most important ways in which the diet of past populations can be reconstructed. The purpose of this study is to assess the prevalence and intensity of caries among the pre‐Hispanic population of Gran Canaria, in order to increase our knowledge about the dietary habits of these people, and to search for differences among the population buried in caves and that buried in tumuli. We studied a total of 791 individuals. Sex was estimated in 561 cases, and age at death, following Brothwell's criteria, in 549. We found that 66.95% of individuals buried in caves and 58.91% of those buried in tumuli showed at least one carious lesion. The proportion of carious teeth was significantlty higher among the population buried in caves (median = 15.71%, interquartile range (IR) = 0–33.33%) than among the population buried in tumuli (median = 6.25%, IR = 0–20%, P = 0.001). Type of burial is the main factor associated with the proportion of carious teeth.These data suggest that the population buried in caves had a different dietary pattern from that of those buried in tumuli. Am J Phys Anthropol, 2005. © 2005 Wiley‐Liss, Inc.
Population continuity vs. discontinuity revisited: Dental affinities among late Paleolithic through Christian‐era Nubians
Authors: Irish Dr. Joel D.
Published: May 2005

The present study revisits a subject that has been a source of long‐standing bioarchaeological contention, namely, estimation of Nubian population origins and affinities. Using the Arizona State University dental anthropology system, frequencies of 36 crown, root, and intraoral osseous discrete traits in 12 late Pleistocene through early historic Nubian samples were recorded and analyzed. Specifically, intersample phenetic affinities, and an indication of which traits are most important in driving this variation, were determined through the application of correspondence analysis and the mean measure of divergence distance statistic. The results support previous work by the author and others indicating that population discontinuity, in the form of replacement or significant gene flow into an existing gene pool, occurred sometime after the Pleistocene. This analysis now suggests that the break occurred before the Final Neolithic. Samples from the latter through Christian periods exhibit relative homogeneity, which implies overall post‐Pleistocene diachronic and regional population continuity. Yet there are several perceptible trends among these latter samples that: 1) are consistent with documented Nubian population history, 2) enable the testing of several existing peopling hypotheses, and 3) allow the formulation of new hypotheses, including a suggestion of two post‐Pleistocene subgroups predicated on an age‐based sample dichotomy. Am J Phys Anthropol, 2005. © 2005 Wiley‐Liss, Inc.
Body proportions in ancient Andeans from high and low altitudes
Authors: Weinstein Karen J.
Published: May 2005

Living human populations from high altitudes in the Andes exhibit relatively short limbs compared with neighboring groups from lower elevations as adaptations to cold climates characteristic of high‐altitude environments. This study compares relative limb lengths and proportions in pre‐Contact human skeletons from different altitudes to test whether ecogeographic variation also existed in Andean prehistory. Maximum lengths of the humerus, radius, femur, and tibia, and femoral head breadth are measured in sex‐specific groups of adult human skeletons (N = 346) from the central (n = 80) and the south‐central (n = 123) Andean coasts, the Atacama Desert at 2,500 m (n = 102), and the southern Peruvian highlands at 2,000–3,800 m (n = 41). To test whether limb lengths vary with altitude, comparisons are made of intralimb proportions, limb lengths against body mass estimates derived from published equations, limb lengths against the geometric mean of all measurements, and principal component analysis. Intralimb proportions do not statistically differ between coastal groups and those from the Atacama Desert, whereas intralimb proportions are significantly shorter in the Peruvian highland sample. Overall body size and limb lengths relative to body size vary along an altitudinal gradient, with larger individuals from coastal environments and smaller individuals with relatively longer limbs for their size from higher elevations. Ecogeographic variation in relation to climate explains the variation in intralimb proportions, and dietary variation may explain the altitudinal cline in body size and limb lengths relative to body size. The potential effects of gene flow on variation in body proportions in Andean prehistory are also explored. Am J Phys Anthropol, 2005. © 2005 Wiley‐Liss, Inc.
Brief communication: mtDNA variation in North Cameroon: Lack of asian lineages and implications for back migration from Asia to sub‐Saharan Africa
Authors: Coia Valentina , Destro‐Bisol Giovanni , Verginelli Fabio , Battaggia Cinzia , Boschi Ilaria , Cruciani Fulvio , Spedini Gabriella , Comas David , Calafell Francesc
Published: May 2005

The hypervariable region‐1 and four nucleotide positions (10400, 10873, 12308, and 12705) of the coding region of mitochondrial DNA (mtDNA) were analyzed in 441 individuals belonging to eight populations (Daba, Fali, Fulbe, Mandara, Uldeme, Podokwo, Tali, and Tupuri) from North Cameroon and four populations (Bakaka, Bassa, Bamileke, and Ewondo) from South Cameroon. All mtDNAs were assigned to five haplogroups: three sub‐Saharan (L1, L2, and L3), one northern African (U6), and one European (U5). Our results contrast with the observed high frequencies of a Y‐chromosome haplogroup of probable Asian origin (R1*‐M173) in North Cameroon. As a first step toward a better understanding of the evident discrepancy between mtDNA and Y‐chromosome data, we propose two contrasting scenarios. The first one, here termed “migration and asymmetric admixture,” implies a back migration from Asia to North Cameroon of a population group carrying the haplotype R1*‐M173 at high frequency, and an admixture process restricted to migrant males. The second scenario, on the other hand, temed “divergent drift,” implies that modern populations of North Cameroon originated from a small population group which migrated from Asia to Africa and in which, through genetic drift, Y‐chromosome haplotype R1*‐M173 became predominant, whereas the Asian mtDNA haplogroups were lost. Am J Phys Anthropol, 2005. © 2005 Wiley‐Liss, Inc.
Activity‐related skeletal change in medieval humeri: Cross‐sectional and architectural alterations
Authors: Rhodes Jill A. , Knüsel Christopher J.
Published: May 2005

This paper examines humeral cross‐sectional properties in two different samples of later medieval date: a group of blade‐injured males from the sites of Towton, North Yorkshire, and Fishergate in the City of York, England, and a comparative group of nonblade‐injured males also from the site of Fishergate in York. CT image slices were taken of the humeral shaft at 20%, 35%, 50%, 65%, and 80% from the distal end to investigate population differences in levels and patterns of mechanical loading. Bilateral asymmetry is investigated and comparisons are made with different populations of varying activity levels. Architectural changes such as humeral torsion are also investigated to determine the relationship between architectural changes and biomechanical efficiency. Results show significant differences in diaphyseal robusticity between the Towton sample and the comparative population, as well as significant differences in diaphyseal shape both between limbs within the Towton sample and between blade‐injured samples. Population differences were also identified in the level of bilateral asymmetry, further demonstrating the differences in movement and activity patterns both between and within samples. These variations may relate to distinctive, more strenuous weapon use and differences in strenuous movement patterns in the two groups. Am J Phys Anthropol, 2005. © 2005 Wiley‐Liss, Inc.
Sexual dimorphism in the Japanese cranial base: A Fourier‐wavelet representation
Authors: Lestrel P.E. , Cesar R.M. , Takahashi O. , Kanazawa E.
Published: May 2005

An approach, computational shape analysis (CSA), is presented here which utilizes a Fourier‐wavelet representation to numerically describe shape features of biological forms. Two elements are involved: 1) elliptical Fourier functions (EFFs), to provide estimates of global aspects, and 2) continuous wavelet transforms (CWTs) to generate an objective estimate of localized features. EFFs are computed, using a set of pseudohomologous points, to create a precise analog of the boundary. This computed contour is then normalized by scaling and rotated in two‐dimensional space to insure a representation that is invariant with respect to starting point, size, and orientation. The predicted point coordinates derived from the EFFs are submitted to CWT for further processing. Wavelet coefficients are then computed to identify localized features, localization being a subjective process with EFFs. The advantage of wavelets is that they eliminate the inevitable subjectivity inherent in the choice of measurements. To test the usefulness of CSA, a sample of cranial base (CB) lateral radiographic outlines was available. Five archaeological periods, Yayoi, Kofun, Kamakura, Edo, and Modern, were utilized (n = 297). Statistically significant differences in sex and archaeological age were found. Although archaeological age differences were present, they were small and random in character, suggesting stability in the CB structures. In contrast, sexually dimorphic differences were present in every group from the Yayoi to the Modern period. This presence of sexually dimorphic differences in shape was consistent with earlier studies of M. nemestrina, G. gorilla, and P. troglodytes. Consequently, it is suggested that the pattern of sexual dimorphism documented in the Japanese CB is a primate pattern with an ancient evolutionary history. The results demonstrate, both visually and numerically, that CSA is a powerful approach for describing both global and localized features of craniofacial structures such as the CB. Am J Phys Anthropol, 2005. © 2005 Wiley‐Liss, Inc.
Effects of cobalt and potassium doping on thermal stability and electrical properties of radiation grafted acrylic acid onto poly(tetrafluoroethylene ethylene) copolymer films
Authors: Ashour Ahmed H. , El‐Sawy Naeem M. , Ghaffar Mahmoud A. Abdel , El‐Shobaky Gamil A.
Published: May 2005

Grafted copolymer of poly(tetrafluoroethylene ethylene) (ET) with acrylic acid (AAc) was prepared by direct radiation method. The obtained films were modified by treating with small amounts of Co2+ and K+ ions (1.0 wt %). The effects of such treatment on the thermal stability and electrical conductivity of these films were studied. Cobalt treatment did not much affect the thermal degradation of the films. The results obtained revealed that k+ treatment enhanced the thermal degradation of ET‐g‐PAAc, which started 273 K lower than that observed in the case of the untreated and Co2+‐treated films. Potassium and cobalt treatment of the investigated films increased their electrical conductivity (σ) and decreased the activation energy ΔEσ. The increase in σ values was, however, more pronounced in the case of K+‐treated film. These results were discussed in terms of the effective increase in the hydrophilicity of the films, especially those treated with potassium. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 867–871, 2005
Conductive effect of an electronic/ionic complex conductivity modifier for silicone elastomers
Authors: Chiu Hsien‐Tang , Wu Jyh‐Horng
Published: May 2005

This study examined silicone, which demonstrated an ionic/electronic compounding conductivity effect through the complexation of polypyrrole (Ppy), carbon black (CB), and a poly(propylene oxide)–poly(ethylene oxide) copolymer with 20 wt % LiClO4 (PEL). Rigid‐body pendulum rheometry was used to observe the processing conditions for the polymer blends, and energy‐dispersive X‐ray spectrometry was used to analyze the distribution depth of the polymer blend surfaces for Ppy. In addition, a digital electrometer was used to test the surface resistance of the composites, and an impedance meter was used to test the dielectric constant and loss factor. The results showed that PEL‐obstructed silicone molecular chain crosslinking, transformed from liquid to solid films, required a higher temperature for curing than silicone because the linear molecular structure of the polymer electrolyte was wound around the silicone polymer network structure, forming a semi‐interpenetrating network. This showed that the Ppy molecule could permeate SP10 blends more deeply. After the silicone was treated with the PEL modifier, the conductivity of Ppy was obstructed. On the other hand, the conductivity of CB showed no significant difference in the SP10 blends. Therefore, after the silicone matrix treatment of the electronic/ionic complex conduction process, there was no incremental effect on the conductivity. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 711–720, 2005
Crystalline and thermal behavior of poly(ethylene terephthalate)/polyphenoxy blends
Authors: Gao Ge , Zhang Limei , Sun Honghai , Chen Guifen , Zhang Ming , Ma Rongtang , Liu Fengqi
Published: May 2005

Poly(ethylene terephthalate) (PET)/polyphenoxy blends were prepared by melt blending. Crystalline and thermal behaviors of PET/polyphenoxy blends were verified by use of DSC. The experiment results show that the initial temperature, peak temperature, and ending temperature of cold crystallization increase with increasing phenoxy content. On the contrary, the onset melting temperature, finishing melting temperature, and peak temperature in the first heating and the secondary heating processes decrease with increasing phenoxy content. The crystallization enthalpy and melting enthalpy, as well as the crystallization rate, decrease with increasing phenoxy content. Avrami exponents of the blends are slightly higher than that of pure PET and almost independent of phenoxy content. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 878–885, 2005
High‐solid‐content emulsions. V. Applications of miniemulsions to high solids and viscosity control
Authors: Ouzineb K. , Graillat C. , McKenna T. F.
Published: May 2005

The use of miniemulsions of styrene and butyl acrylate to make high‐solid‐content, low‐viscosity latices was investigated. Products were obtained with solid concentrations greater than 70 wt % and viscosities as low as 350 mPa s at shear rates of 20 s−1. This was possible with monomodal and bimodal latices. In addition, the compartmentalization of the reactive species in the miniemulsion systems was exploited to produce latices with high solid concentrations, low viscosities, and bimodal molecular weight distributions. This demonstrated a potentially interesting application for this sort of material. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 745–752, 2005
The effect of heat sealing temperature on the properties of OPP/CPP heat seal. I. Mechanical properties
Authors: Tetsuya Tsujii , Ishiaku U. S. , Mizoguchi Machiko , Hamada Hiroyuki
Published: May 2005

The effect of heat sealing temperature on the mechanical properties and morphology of OPP/CPP laminate films was investigated. The laminated films were placed in an impulse type heat sealing machine with both CPP sides facing each other. The temperatures investigated ranged from 100 to 250°C. T‐peel and tensile tests in combination with SEM were used to characterize the heat seals. A minimum seal initiation temperature of 120°C was identified for OPP/CPP laminate heat sealing. Peel strength increased sharply from zero at 110°C to maximum at 120°C, after which a gradual decrease was observed. Tensile strength initially increased until 120°C, after which it gradually decreased until 170°C and assumed a constant value beyond that. The initial rise has been associated to cold crystallization, while the reduction between 120°C and 170°C was due to relaxation in molecular orientation. Beyond 170°C, all the orientation in the laminate has been lost so orientation effects are nullified. Morphological studies with SEM revealed that seals were partially formed at lower temperatures, while the laminates were totally fused together at high temperatures, with intermediate temperatures showing properties that lie in between. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 753–760, 2005
Potentiometric and thermodynamic studies of vinylacetic acid and its metal complexes in monomeric and polymeric forms
Authors: Al‐Sarawy Ahmed A.
Published: May 2005

Proton–monomeric ligand dissociation and metal–monomeric ligand stability constants of vinylacetic acid (VA) with some metal ions were calculated potentiometrically in 0.1M KCl. Also, in the presence of 2,2′‐azobisisobutyronitrile as initiator, the proton–polymeric ligand dissociation and metal–polymeric ligand stability constants were calculated. The effect of temperature on the dissociation of VA and the stability of its formed complexes were studied in monomeric and polymeric forms. The corresponding thermodynamic functions were derived and discussed. The dissociation process was nonspontaneous, endothermic, and entropically unfavorable. The formation of the metal complexes was found to be spontaneous, endothermic, and entropically favorable. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 952–956, 2005
Functionalization and cross‐linking of high‐density polyethylene in the presence of dicumyl peroxide—An FTIR study
Authors: Anbarasan R. , Babout O. , Dequiel M. , Maillard B.
Published: May 2005

High‐density polyethylene was thermolysed with short‐chain organic compounds (additives) with an ester functional group in the presence of free radical initiator such as dicumyl peroxide at 160°C. The experimental results inferred that an additive with a hydrogen donor containing a thiol group showed better efficiency toward functionalization and an additive with a methylene bridged group showed better efficiency toward cross‐linking. The FTIR spectral results indicated that the area of the carbonyl peak at 1730 cm−1 increased with the increase in percentage grafting of additives with simultaneous increase of cross‐linking. The ester grafting was further confirmed by saponification reaction. The possibility of acid functionalization via intramolecular hydrogen transfer was also checked through acid hydrolysis of the saponified products. A suitable reaction mechanism was proposed in order to explain the experimental and spectral data obtained. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 766–774, 2005
Sulfur‐free lignin as reinforcing component of styrene–butadiene rubber
Authors: Košíková B. , Gregorová A.
Published: May 2005

The potential application of lignin biopolymer as a component of styrene–butadiene rubber was examined with regard to its ability to reinforce the vulcanizates. It was shown that the sulfur‐free lignin preparation improved physicomechanical properties of rubber. The determination of the coefficient of lignin activity confirmed that lignin acts as an active filler. FTIR characteristics of lignin isolated from the vulcanizate containing 20 phr lignin indicated its interaction with the sulfur system, resulting in formation of noncyclic sulfide structures. In the case of higher lignin amount in the vulcanizate, some interfacial interaction between lignin and SBR may occur. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 924–929, 2005
Swelling of polymeric glove materials during permeation by solvent mixtures
Authors: Georgoulis L. B. , Morgan M. S. , Andrianopoulos N. , Seferis J. C.
Published: May 2005

Extrapolation from permeation data for pure solvents does not predict accurately their behavior in mixtures. In this study we examined whether the permeation of natural rubber, nitrile, and PVA glove materials by solvent mixtures is proportional to material swelling. Gloves were exposed to solvent mixtures and their permeation was monitored: breakthrough times, permeation rates, and degree of swelling were determined. Toluene exhibits higher permeation than MEK through natural rubber. Adding MEK to toluene decreased the permeation of toluene and increased that of MEK, proportionally to mixture composition and the degree of swelling. The opposite was observed for nitrile: toluene, now the “low permeation” solvent (LPS), retarded MEK permeation and vice versa. The effect was proportional to mixture composition but not consistently proportional to the degree of swelling. Samples were also exposed to the LPS for different time periods prior to a permeation run using the “high permeation” solvent (HPS). The decrease in breakthrough time of the HPS was proportional to the degree of swelling caused by the LPS. Material swelling appears to control MEK and toluene permeation through natural rubber. For nitrile, additional factors are apparently at work. No permeation was detected through PVA and material swelling was negligible. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 775–783, 2005
Effect of the polymer glass transition on the chromatographic retention volumes
Authors: Vrentas J. S. , Vrentas C. M.
Published: May 2005

Theoretical developments are presented that explain four experimental observations concerning the temperature dependence of chromatographic specific retention volumes. A theoretical framework is proposed for a method that can be used to determine the glass‐transition temperature of the pure polymer and for a method of characterizing the concentration dependence of the glass‐transition temperature of a polymer–solvent system. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 793–796, 2005
Comparative study of the recovery of silver(I) from aqueous solutions with different chelating resins derived from glycidyl methacrylate
Authors: Atia Asem A. , Donia Ahmed M. , Yousif Ahmed M.
Published: May 2005

Glycidyl methacrylate (GMA) was polymerized in the presence of divinylbenzene (DVB). The GMA/DVB resin was immobilized with different chelating moieties containing nitrogen or sulfur donor atoms. The resins obtained [an amino‐bearing resin (RI), an amino/thiocarbamate‐bearing resin (RII), a triazole‐bearing resin (RIII), and an amino/thiol‐bearing resin (RIV)] were tested toward the recovery of Ag(I) from its aqueous solutions. The adsorption behavior of Ag(I) and the resin regeneration were studied. The sulfur‐containing resins showed higher uptake and lower elution efficiency than those containing nitrogen. The maximum uptake values were 1.20, 1.33, 1.40, and 2.86 mmol/g for RI, RII, RIII, and RIV, respectively. The mechanism of interaction between Ag(I) and the resins is also suggested. Regeneration was achieved with a 0.5N thiourea solution, acidified thiourea, or 0.5N H2SO4, where the resins were stable over five cycles. Elution efficiencies of 94–96 and 90–93% were achieved for the nitrogen‐ and sulfur‐containing resins, respectively. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 806–812, 2005
Influence of the glycol component in dibenzoate plasticizers on the properties of plasticized PVC films
Authors: Wardzińska Elżbieta , Penczek Piotr
Published: May 2005

A series of glycol dibenzoates was synthesized by transesterification of glycols with methyl benzoate. PVC films were prepared from suspension grade PVC and the dibenzoates at a constant content of the dibenzoates. The mechanical properties of the films were measured. In addition, the extractability and the absorption of various liquids was determined. The effect of the structure of the glycol component in the dibenzoates on the mechanical properties of the films and the plasticizing efficiency was investigated. Neopentyl glycol dibenzoate exhibits the highest plasticizing effect, followed by triethylene and ethylene glycol dibenzoates and the 2‐(n‐butyl)‐2‐ethyl‐1,3‐propanediol derivative. It was found that the ether linkages in the dibenzoates mainly contribute to the plasticization of PVC. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 822–824, 2005
Microstructure and fracture behavior of (co)injection‐molded polyamide 6 composites with short glass/carbon fiber hybrid reinforcement
Authors: Solomon S. , Bakar A. Abu , Ishak Z. A. Mohd , Ishiaku U. S. , Hamada H.
Published: May 2005

The mechanical and fracture properties of injection molded short glass fiber)/short carbon fiber reinforced polyamide 6 (PA 6) hybrid composites were studied. The short fiber composites of PA 6 glass fiber, carbon fiber, and the hybrid blend were injection molded using a conventional machine whereas the two types of sandwich skin–core hybrids were coinjection molded. The fiber volume fraction for all formulations was fixed at 0.07. The overall composite density, volume, and weight fraction for each formulation was calculated after composite pyrolysis in a furnace at 600°C under nitrogen atmosphere. The tensile, flexural, and single‐edge notch‐bending tests were performed on all formulations. Microstructural characterizations involved the determination of thermal properties, skin–core thickness, and fiber length distributions. The carbon fiber/PA 6 (CF/PA 6) formulation exhibits the highest values for most tests. The sandwich skin‐core hybrid composites exhibit values lower than the CF/PA 6 and hybrid composite blends for the mechanical and fracture tests. The behaviors of all composite formulations are explained in terms of mechanical and fracture properties and its proportion to the composite strength, fiber orientation, interfacial bonding between fibers and matrix, nucleating ability of carbon fibers, and the effects of the skin and core structures. Failure mechanisms of both the matrix and the composites, assessed by fractographic studies in a scanning electron microscope, are discussed. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 957–967, 2005
Study on flammability of montmorillonite/styrene‐butadiene rubber (SBR) nanocomposites
Authors: Zhang Huifeng , Wang Yiqing , Wu Youping , Zhang Liqun , Yang Jun
Published: May 2005

The flammability of montmorillonite (MMT)/SBR nanocomposites, prepared by the technique of cocoagulating rubber latex and clay aqueous suspension, was investigated. Flammability studies, performed on the cone calorimeter, showed that the maximum heat release rate (HRR) of SBR decreased from 1987 to 1442 kw/m2 with the introduction of nanoclay (20 phr). This nanocomposite had the lowest mass loss rate and the largest amount of char upon combustion compared with conventional SBR composites with the same clay loading and pure SBR. The permeability properties of MMT/SBR composites were also measured. It was deduced that the lowered permeability was responsible for the reduced mass loss rate and hence the lower HRR. Unfortunately, the oxygen index (OI) of the nanocomposites was not as high as expected. Combination of Mg(OH)2 and clay was effective for the improvement of both mechanical properties and OI. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 844–849, 2005
Study on morphology of compatibilized poly (vinyl chloride)/ultrafine polyamide‐6 blends by styrene–maleic anhydride
Authors: Xiong Chuanxi , Lu Shengjun , Wang Tao , Hong Yang , Chen Tao , Zhou Zhiyong
Published: May 2005

Ultrafine polyamide‐6 (UPA6) with a size of 4–8 μm was prepared via jet‐milling. Blends of poly (vinyl chloride) (PVC) and UPA6 using a reactive copolymer styrene–maleic anhydride (SMA‐18%) were prepared. The change in morphology and structure of the blends were studied using differential scanning calorimetry, scanning electron microscopy, and X‐ray diffraction. The blend behavior was also determined experimentally using dynamic mechanical analysis. Contrasted to the original PA6, the crystallinity of the UPA6 decreased, the size of its crystallites were reduced, and its melting point decreased to 175°C. In all blends, PVC formed the continuous matrix phase. SMA is miscible with PVC and tends to be dissolved in the PVC phase during the earlier stages of blending. The dissolved SMA has the opportunity to react with PA6 at the interface to form the desirable SMA‐g‐PA6 copolymer. This in situ formed SMA‐g‐PA6 graft copolymer tends to anchor along the interface to reduce the interfacial tension and results in finer phase domains. Cocrystallity existed in PVC/(UPA6/SMA) at a ratio of 82/(18/5). © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 850–854, 2005
Studies on cellulose acetate‐carboxylated polysulfone blend ultrafiltration membranes. III
Authors: Sajitha C. J. , Mohan D.
Published: May 2005

Enhancement of the hydrophilicity in polymeric membrane materials results in membranes with higher flux and better membrane characteristics. Hence, polysulfone was carboxylated and ultrafiltration membranes were prepared from blends of cellulose acetate and carboxylated polysulfones having various degrees of carboxylation with a total polymer concentration of 20 wt % in casting solution and at different blend polymer compositions. The effects of degree of carboxylation on membrane characteristics such as compaction, pure water flux, and membrane hydraulic resistance (Rm) have been investigated. The influence of the polymer concentration in the blend solution on the performance of blend membranes at various blend polymer compositions has also been investigated and compared with that of blend membranes prepared from blends of cellulose acetate and polysulfone or carboxylated polysulfone with a total polymer concentration of 17.5 wt %. Further, the solute rejection performance of the membranes has also been investigated by subjecting the membranes to metal ion permeation studies using polyelectrolyte‐enhanced ultrafiltration. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 976–988, 2005
Preparation of reactive mineral powders used for poly(sodium acrylate) composite superabsorbents
Authors: Lee Wen‐Fu , Chen Yung‐Chu
Published: May 2005

Reactive mineral powders were prepared with a vinyl monomer as an intercalating agent, which was grafted onto the surface of nanoclay layers, to offer crosslinking points between the nanoclay layers. According to IR characterization, the vinyl group of (3‐acrylamidopropyl)trimethylammonium chloride, grafted onto the clay, disappeared after polymerization was performed. This spectral evidence confirmed that the reaction occurred between the clay layers. Thermogravimetric curves showed that the weight percentage remaining at 750°C for the intercalated clay/sodium acrylate nanocomposites was about 5 wt % higher than that for organic poly(sodium acrylate). This indicated that the clay was not diminished in the polymerization, and this process produced intercalated mica with a quaternary ammonium content of approximately 38.8 mmol/100 g and intercalated montmorillonite with a quaternary ammonium content of approximately 45.36 mmol/100 g. We also investigated the effect of reactive clays on the crystalline morphology and water absorbency for these nanocomposite hydrogels. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 855–861, 2005
Crosslinking of cotton cellulose in presence of alkyl di‐allyl ammonium salts. III. Study on pore structure of treated fabrics from dyeing kinetics
Authors: Chen Jui‐Chin
Published: May 2005

Two kinds of alkyl di‐allyl ammonium salts (alkyl groups = methyl and propyl) as crosslinking agents are combined with dimethyloldihydroxyethyleneurea (DMDHEU) to study rate constants, structural diffusion resistance constants, and other parameters of dyeing. The dye absorptions for the various crosslinking agents are ranked DMDHEU–propyl di‐allyl ammonium salt > DMDHEU–methyl di‐allyl ammonium salt > DMDHEU, and the equilibrium absorption values are ranked DMDHEU–propyl di‐allyl ammonium salt > DMDHEU–methyl di‐allyl ammonium salt > DMDHEU. The dyeing rate constants and structural diffusion resistance constants of the finished fabrics are in the order DMDHEU–methyl di‐allyl ammonium salt > DMDHEU–propyl di‐allyl ammonium salt > DMDHEU; however, the activation energies are ranked inversely. The treated fabrics for DMDHEU–alkyl di‐allyl ammonium salts have a larger pore structure than those for DMDHEU. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 862–866, 2005
Synthesis and characterization of amphiphilic block copolymers of methyl methacrylate with poly(ethylene oxide) macroinitiators formed by atom transfer radical polymerization
Authors: Krishnan R. , Srinivasan K. S. V.
Published: May 2005

Amphiphilic ABA triblock copolymers of poly(ethylene oxide) (PEO) with methyl methacrylate (MMA) were prepared by atom transfer radical polymerization in bulk and in various solvents with a difunctional PEO macroinitiator and a Cu(I)X/N,N,N′,N″,N″‐pentamethyldiethylenetriamine catalyst system at 85°C where X=Cl or Br. The polymerization proceeded via controlled/living process, and the molecular weights of the obtained block copolymers increased linearly with monomer conversion. In the process, the polydispersity decreased and finally reached a value of less than 1.3. The polymerization followed first‐order kinetics with respect to monomer concentration, and increases in the ethylene oxide repeating units or chain length in the macroinitiator decreased the rate of polymerization. The rate of polymerization of MMA with the PEO chloro macroinitiator and CuCl proceeded at approximately half the rate of bromo analogs. A faster rate of polymerization and controlled molecular weights with lower polydispersities were observed in bulk polymerization compared with polar and nonpolar solvent systems. In the bulk polymerization, the number‐average molecular weight by gel permeation chromatography (Mn,GPC) values were very close to the theoretical line, whereas lower than the theoretical line were observed in solution polymerizations. The macroinitiator and their block copolymers were characterized by Fourier transform infrared spectroscopy, 1H‐NMR, matrix‐assisted laser desorption ionization time‐of‐flight mass spectrometry, thermogravimetry (TG)/differential thermal analysis (DTA), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). TG/DTA studies of the homo and block copolymers showed two‐step and multistep decomposition patterns. The DSC thermograms exhibited two glass‐transition temperatures at −17.7 and 92°C for the PEO and poly(methyl methacrylate) (PMMA) blocks, respectively, which indicated that microphase separation between the PEO and PMMA domains. SEM studies indicated a fine dispersion of PEO in the PMMA matrix. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 989–1000, 2005
Morphology determination of functional poly[2‐methoxy‐5‐(3,7‐dimethyloctyloxy)‐1,4‐phenylenevinylene]/poly[oxa‐1,4‐phenylene‐1,2‐(1‐cyanovinylene)‐2‐methoxy,5‐(3,7‐dimethyloctyloxy)‐1,4‐phenylene‐1,2‐(2‐cyanovinylene)‐1,4‐phenylene] blends as used for all‐polymer solar cells
Authors: Loos Joachim , Yang Xiaoniu , Koetse Marc M. , Sweelssen Jörgen , Schoo Herman F. M. , Veenstra Sjoerd C. , Grogger Werner , Kothleitner Gerald , Hofer Ferdinand
Published: May 2005

Poly[2‐methoxy‐5‐(3,7‐dimethyloctyloxy)‐1,4‐phenylenevinylene] (MDMO‐PPV) blended with poly[oxa‐1,4‐phenylene‐1,2‐(1‐cyanovinylene)‐2‐methoxy,5‐(3,7‐dimethyloctyloxy)‐1,4‐phenylene‐1,2‐(2‐cyanovinylene)‐1,4‐phenylene] (PCNEPV) has been used as the active layer for an all‐polymer photovoltaic cell. The photovoltaic performance of devices is improved by a thermal treatment, which alters the morphology of the active layer. The morphology of the MDMO‐PPV/PCNEPV blend has been studied with conventional transmission electron microscopy and energy‐filtered transmission electron microscopy based on electron energy loss spectroscopy. The nitrogen of the cyano group within the PCNEPV has been be detected, and two‐dimensional nitrogen distribution maps have been acquired. Nitrogen‐rich domains have a size of approximately 20–50 nm and are homogeneously distributed over the entire film. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1001–1007, 2005