bluuebunny/crossref_metadata_2025_split huggingface dataset:
New porous perfluoropolyether membranes
Authors: Chaouk Hassan , Wilkie John S. , Meijs Gordon F. , Cheng Han Ying 
Published: August 2002

AbstractA new family of porous fluorinated membranes was developed from perfluoropolyethers (PFPEs). The PFFE–dimethacrylate (3) was dispersed in isopropanol to form a clear homogeneous solution, which after UV curing in polypropylene molds formed a porous polymer disk. A series of 10 polymers was prepared with ratios of isopropanol to PFPE ranging from 1.3:1 to 0.2:1. The water content of the membranes after hydration varied from 56 to 7% (w/w) and was directly proportional to the percentage of isopropanol used in the polymerization. However, the tensile elastic modulus, which ranged from 0.17 to 15 MPa, was inversely proportional to the water content. The high water content membranes [52 and 46% (w/w)] had a similar permeability to glucose, inulin, and albumin, while the membranes with lower water contents of 37 and 25% displayed progressively lower permeability. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1756–1763, 2001
Modeling the role of stabilizing additives during melt recycling of high‐density polyethylene
Authors: Tsenoglou C. , Kartalis C. N. , Papaspyrides C. D. , Pfaendner R. 
Published: August 2002

AbstractPost‐use high‐density polyethylene, almost devoid of any stabilizing agents, was restabilized in various degrees and subjected to multiple extrusion cycles at different reprocessing temperatures for assessing its chemical stability. The process‐induced material degradation was attributed primarily to long‐chain branching caused by crosslinking. It was monitored by an increase in viscosity and evaluated on the basis of an approximate expression derived using fundamental principles of macromolecular rheology. It was determined that long‐chain branching increases with temperature and the extent of processing, while decreasing with the amount of restabilizing agent added. A simple model was developed to quantitatively describe the progress of the chemical change by relating it to key material and operational variables. Besides constituting a useful method of monitoring and controlling polymer modification during processing, this model suggests ways of optimizing stabilization according to the particular processing and product requirements. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2207–2217, 2001
Thermogravimetric analysis of poly(3‐hydroxybutyrate) and poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate)
Authors: Li Si‐Dong , Yu Peter H. , Cheung Man Ken 
Published: August 2002

AbstractThe thermal degradation of poly(3‐hydroxybutyrate) (PHB) and poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) [P(HB‐HV)] was studied using thermogravimetry (TG). In the thermal degradation of PHB, the temperature at the onset of weight loss (To) was derived by To = 0.97B + 259, where B represents the heating rate (°C/min). The temperature at which the weight loss rate was maximum (Tp) was Tp = 1.07B + 273, and the final temperature (Tf) at which degradation was completed was Tf = 1.10B + 280. The percentage of the weight loss at temperature Tp (Cp) was 69 ± 1% whereas the percentage of the weight loss at temperature Tf (Cf) was 96 ± 1%. In the thermal degradation of P(HB‐HV) (7:3), To = 0.98B + 262, Tp = 1.00B + 278, and Tf = 1.12B + 285. The values of Cp and Cf were 62 ± 7 and 93 ± 1%, respectively. The derivative thermogravimetric (DTG) curves of PHB confirmed only one weight loss step change because the polymer mainly consisted of the HB monomer only. The DTG curves of P(HB‐HV), however, suggested multiple weight loss step changes; this was probably due to the different evaporation rates of the two monomers. The incorporation of 10 and 30 mol % of the HV component into the polyester increased the various thermal temperatures (To, Tp, andTf) by 7–12°C (measured at B = 20°C/min). © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2237–2244, 2001
Influence of reaction between second monomer and vinyl group of seed polysiloxane on seeded emulsion polymerization
Authors: He Wei‐Dong , Pan Cai‐Yuan 
Published: August 2002

AbstractSeeded emulsion polymerization of methyl methacrylate (MMA) or styrene (ST) was carried in the presence of different vinyl‐containing polysiloxane latices (SV‐*) and the core‐shell particles with poly(methyl methacrylate) (PMMA) or polystyrene (PST), as the shells were obtained under different polymerization conditions. Besides the compatibility of the vinyl monomer and its polymer with polysiloxane and the reaction between vinyl monomer with vinyl group of polysiloxane, the content of vinyl group of seed polysiloxane has influence on the morphology and component of the resulted composite particles. The mechanism for the formation of core‐shell structure is discussed. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2752–2758, 2001
Ternary polymer composites: PA6,6/maleated SEBS/glass beads
Authors: Tjong S. C. , Xu S. A. 
Published: August 2002

AbstractPolyamide 6,6 (PA6,6)/maleated styrene–hydrogenated butadiene–styrene (SEBS) blends filled with up to 20% spherical glass beads (GBs) were prepared by extrusion and subsequent injection molding. Tensile and impact tests were used to examine the effect of GB additions on the mechanical behavior of PA6,6/SEBS–g–MA 80/20 blend. Tensile measurements showed that the GB additions improve the stiffness of the PA6,6/SEBS–g–MA 80/20 blend but had little effect on its tensile ductility. The impact test revealed that the impact strength of PA6,6/SEBS–g–MA 80/20 blend tends to decrease with increasing GB content. Therefore, the GB additions were beneficial to maintain a stiffness‐to‐toughness balance of the PA6,6/SEBS–g–MA 80/20 blend. Finally, the correlation between the experimental tensile stiffness and strength with various theoretical models is discussed. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3231–3237, 2001
Thermal analyses of poly(3‐hydroxybutyrate), poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate), and poly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate)
Authors: He Ji‐Dong , Cheung Man Ken , Yu Peter H. , Chen Guo‐Qiang 
Published: August 2002

AbstractThermal analyses of poly(3‐hydroxybutyrate) (PHB), poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) [P(HB–HV)], and poly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate) [P(HB–HHx)] were made with thermogravimetry and differential scanning calorimetry (DSC). In the thermal degradation of PHB, the onset of weight loss occurred at the temperature (°C) given by To = 0.75B + 311, where B represents the heating rate (°C/min). The temperature at which the weight‐loss rate was at a maximum was Tp = 0.91B + 320, and the temperature at which degradation was completed was Tf = 1.00B + 325. In the thermal degradation of P(HB–HV) (70:30), To = 0.96B + 308, Tp = 0.99B + 320, and Tf = 1.09B + 325. In the thermal degradation of P(HB–HHx) (85:15), To = 1.11B + 305, Tp = 1.10B + 319, and Tf = 1.16B + 325. The derivative thermogravimetry curves of PHB, P(HB–HV), and P(HB–HHx) confirmed only one weight‐loss step change. The incorporation of 30 mol % 3‐hydroxyvalerate (HV) and 15 mol % 3‐hydroxyhexanoate (HHx) components into the polyester increased the various thermal temperatures To, Tp, and Tf relative to those of PHB by 3–12°C (measured at B = 40°C/min). DSC measurements showed that the incorporation of HV and HHx decreased the melting temperature relative to that of PHB by 70°C. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 90–98, 2001
Analysis of a crease‐resisting finish on linen fabrics using Fourier transform infrared spectroscopy and visible and near‐infrared spectroscopy
Authors: Mccall R. D. , Kernaghan K. J. , Sharma H. S. S. 
Published: August 2002

AbstractA wide range of chemical reagents are capable of producing a satisfactory crease‐resisting finish for cellulosic fabrics and are currently available on the market. However, these agents do not work as efficiently on linen relative to cotton or rayon. Untreated linen controls and samples treated with a N‐methylol reagent were investigated for physical and chemical changes, and an attempt was made to quantify the crosslinking bonds formed and assess other changes in the treated fabrics using Fourier transform infrared spectroscopy (FTIR) and visible and near‐infrared spectroscopy (NIR). The results were compared with nitrogen analysis data, crease‐recovery angle measurements, and abrasion‐resistance tests in an attempt to assess the effectiveness of the treatment relative to the responses of the instrumental techniques. This study shows correlations between the visible and NIR and FTIR spectra and the crease‐recovery angle and abrasion resistance. The study also indicates that FTIR may be useful in assessing the crosslinking bonding changes associated with the dimethylol urea treatment of linen to achieve improved crease recovery. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1886–1896, 2001
A novel approach for the determination of the physicomechanical properties of polymers by vibrational spectroscopy: The tensile strength of polybutadiene rubber
Authors: Pandey G. C. , Kumar Ajay , Garg R. K. 
Published: August 2002

AbstractIn an attempt to extend the applications of IR spectroscopy, we report here on a novel method for the determination of the tensile strength (Ts) of polybutadiene rubber (PBR). A simple linear correlation between Ts and the peak absorbance ratio was developed. The method is simple, direct, and fast and involves only the measurement of the absorbance ratio from the IR spectrum of PBR film. The results obtained by this (IR‐based) method and the currently used (ASTM) method, for quality control/quality assurance purposes, were in good agreement. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2135–2139, 2001
Graft copolymerization of methyl acrylate onto nylon1010 initiated by potassium diperiodatonickelate(IV)
Authors: Liu Yinghai , Li Weiping , Deng Kuilin , Zhang Jinsong 
Published: August 2002

AbstractIn this article, the graft copolymerization of methyl acrylate (MA) onto nylon1010 by using potassium diperiodatonickelate(IV) [Ni(IV)]–nylon1010 redox system as initiator was studied in alkaline medium. The effect of different factors on grafting parameters was investigated. The structure of the graft copolymer was determined by infrared (IR), X‐ray diffraction, and scanning electron microscope (SEM). It was found that Ni(IV)–nylon1010 system is an efficient redox initiator for this graft copolymerization. A single‐electron transfer mechanism is proposed to explain the formation of radicals and the initiation. The graft copolymer was used as the compatibilizer in blends of poly(methyl methacrylate) (PMMA) and nylon1010. The SEM photographs indicate that the graft copolymer greatly improved the compatibility of the blend. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2636–2640, 2001
Effects of ethyl acetate on the soap‐free emulsion polymerization of 4‐vinylpyridine and styrene. I. Aspects of the mechanism
Authors: Ni Henmei , Ma Guanghui , Nagai Masatoshi , Omi Shinzo 
Published: August 2002

AbstractA series of experiments were carried out on the soap‐free emulsion polymerization mechanism of 4‐vinyl pyridine (4VP)/styrene (St) and the solvent, ethyl acetate (EA), by using the cationic initiator, 2,2′‐azobis(2‐amidinopropane) 2HCl (V50). To investigate the mechanism of polymerization in detail, a particular quasi‐static polymerization system—the reaction mixture in a sealed bottle allowed to stand without agitation during the whole polymerization period—was employed. The partition of monomers at ambient and solid content of the latex during the quasi‐static polymerization in the presence of 8 wt % EA was measured by 1H‐NMR, and the variation of particle size was observed by scanning electron microscopy (SEM). The solubility of 4VP and St in water decreased as the amount of EA increased. Meanwhile, most of the EA was partitioned in the oil phase, even in the cases where the charged amount of EA was much lower than the solubility of EA (∼ 8 wt %) in water at ambient. The solubility of EA in water was also affected by the composition of 4VP and St (i.e., increased as the fraction of 4VP increased, but decreased as the fraction of St increased). This observation, as well as the quantitative analysis of the quasi‐static emulsion polymerization, indicated that the initial reaction in the soap‐free emulsion polymerization was closely related to the disturbance of the interface of monomer/water phase, which triggered the generation of monomer droplets. Therefore, a new mechanism was proposed for the nucleation of soap‐free emulsion polymerization, namely, the nucleation was performed in the droplets. The droplets absorbed the oligomeric radicals generated in the aqueous phase to continue the polymerization, as well as to promote the colloidal stability of the droplets. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2679–2691, 2001
Effects of ethyl acetate on the soap‐free emulsion polymerization of 4‐vinylpyridine and styrene. II. Aspects of the mechanism
Authors: Ni Henmei , Ma Guanghui , Nagai Masatoshi , Omi Shinzo 
Published: August 2002

AbstractThe kinetics of the soap‐free emulsion polymerization of 4‐vinylpyridine and styrene, as well as the morphology development during the polymerization, were investigated with 1H‐NMR, scanning electron microscopy, transmission electron microscopy, and differential scanning calorimetry. To clarify the process of particle nucleation and particle growth, we focused on the effects of the addition of ethyl acetate (8 wt %) combined with lower rates of agitation (100 and 200 rpm). The results showed that both the nucleation and the growth of particles were related to the monomer droplets stemming from the interface of the monomer and aqueous phases by the disturbance by agitation and/or from the condensation of monomers dissolved in the aqueous phase. Besides the diffusion of monomer molecules through the aqueous phase, the incorporation, among the species previously formed, of monomer droplets was a major cause of monomer transport in the emulsion polymerization system. The particle morphology was controlled by the miscibility of the monomers and (co)polymer, rather than the phase separation due to the different compositions of the copolymers in the particles. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2692–2708, 2001
Dissolution of latex films after γ‐ray treatment
Authors: Aydin K. , Adiyaman N. , Uğur Ş. , Pekcan Ö. 
Published: August 2002

AbstractLatex films were prepared by annealing pyrene (Py)‐labeled poly(methyl methacrylate) particles at glass‐transition temperature (100°C). These films were then irradiated by γ‐rays from 60Co in a gamma cell at room temperature at the same dose rate (rad/h) for 30 min. Before dissolution films were annealed at elevated temperatures for a 30‐min time interval to complete the film formation process. Steady‐state fluorescence (SSF) technique were used to monitor the dissolution of these irradiated latex films. The dissolution of films in chloroform–heptane (80–20%) mixture was monitored in real time by the Py fluorescence intensity change. Relaxation constants k0 and desorption coefficients Dd of polymer chains were measured. It was observed that both Dd and k0 values first increased and then decreased by increasing the annealing temperature. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 129–137, 2002
Influence of different dopants on the adsorption, morphology, and properties of self‐assembled films of poly(o‐ethoxyaniline)
Authors: Paterno Leonardo G. , Mattoso Luiz H. C. 
Published: August 2002

AbstractSelf‐assembled films of poly(o‐ethoxyaniline)—POEA alternated with sulfonated lignin (SL)—were successfully produced, and their kinetics of formation and growth investigated for different dopants (hydrochloric acid, methanesulfonic acid, p‐toluenesulfonic acid, and camphorsulfonic acid). These films were characterized by ultraviolet‐visible spectroscopy, atomic force microscopy, surface potential, and electrical resistance measurements. It has been observed that the bulkiest dopants led to a greater time for the polymer deposition and greater amount of material adsorbed. This can be explained by the lower mobility and lower solvation of the bulkiest dopant counterions, which led to a higher screening effect of the charges present in the POEA chains and therefore to a more compact molecular conformation. The morphology of the POEA films were also greatly affected by the type of dopant used, being rougher for the bulkiest dopants. The POEA films also exhibited different electrical responses upon ethylene exposure depending on the dopant, indicating a promising use for gas sensor applications. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1309–1316, 2002
Community patterns generated by human harvesting on Chilean shores: a review
Authors: Moreno Carlos A. 
Published: August 2002

Abstract1. The Chilean rocky coast has been exploited for food by coastal gatherers for at least 8500 years BP and probably was an important factor in how prehistoric people were able to colonize the South Americas Pacific Rim. The main species targeted in the past were the same as those today except that now the gatherers are resident and the fishing activity is more intense and persistent.2. With many pertinent studies from around the world having been published on this topic, mostly conducted in Marine Reserves, this review tries to identify the main patterns that can help us recognize, in the Chilean intertidal, the degree of exploitation on wave exposed and wave protected rocky shore habitats.3. Three clear patterns were identified depending on the trophic level adopted by the human gatherers in the food chain of the intertidal zone. First, when the humans act as herbivores, collecting the large laminarian Durvillaea antarctica, adult plants disappear from the accessible sites, especially the midlittoral, semi‐exposed and exposed habitats.4. Second, when humans harvest the ecologically important herbivorous archeogastropoda Fissurella spp., this results in the red alga Mazzaella laminarioides covering almost 100% of the midlittoral rocks. Third, when humans become top predators by collecting the muricid carnivore Concholepas concholepas, then bivalves, mainly Perumytilus purpuratus, cover the rocks in multiple layers.5. These patterns contribute to the evaluation of the state of conservation of the Chilean rocky intertidal shores, especially because the north and the south are beginning to be connected by a new coastal road. Thus it is necessary to evaluate urgently, on a large spatial scale, the state of conservation of these communities, in order to help select the appropriate places for establishing Marine Reserves.Copyright © 2001 John Wiley & Sons, Ltd.
Endocast of Sambungmacan 3 (Sm 3): A new Homo erectus from Indonesia
Authors: Broadfield Douglas C. , Holloway Ralph L. , Mowbray Kenneth , Silvers Adam , Yuan Michael S. , Márquez Samuel 
Published: August 2002

AbstractA new fossil calvaria, Sambungmacan 3 (Sm 3), described in New Fossil Hominid Calvaria From Indonesia—Sambungmacan 3 by Márquez et al., this volume, yields one of the most advanced and complete endocasts yet recovered from Java. This communication provides a thorough interpretation of the external anatomical landmarks observable on Sm 3. Using computer tomography (CT) and traditional morphological measurements, our comparative paleoneurological analyses show that while Sm 3 has a mosaic of features that are similar to both Indonesian and Chinese H. erectus, it also possesses significant characters reminiscent of later hominins. These include a greater degree of asymmetry characterized by a possible left‐occipital, right‐frontal petalial pattern, left‐right volumetric cerebral asymmetry, and marked asymmetry in Broca's cap. Moreover, the frontal lobe offers a more rounded, shortened appearance in contrast to the flat, elongated appearance of other Indonesian fossils (e.g., Sangiran 17). Another unique trait is exhibited in the transverse plane where the widest breadth of Sm 3 occurs more superiorly than in other Indonesian H. erectus. Thus, the endocast of Sm 3 presents a unique morphology not seen previously in the hominin fossil record. While the strong modern human characteristics in this endocast may not represent a particular ancestry, they do allow us to recognize a new dimension of the remarkable variation in Indonesian Homo erectus. Anat Rec 262:369–379, 2001. © 2001 Wiley‐Liss, Inc.
Virtual anthropology (VA): A call for Glasnost in paleoanthropology
Authors: Weber Gerhard W. 
Published: August 2002

AbstractThe adventurous scientist, with a hat protecting him from the fierce sun as he travels from one remote place to another, hunting for fossils of our ancestors, has been a part of the romantic imagination associated with anthropological research in the 20th Century. This picture of the paleoanthropologist still retains a grain of truth. Indeed, many new sites were discovered under troublesome conditions in the recent past and have added substantial information about our origins. But on another front, probably less sensational but no less important, are contributions stemming from the analysis of the already discovered fossils. With the latter, a rapid evolution in anthropologic research took place concurrently with advances in computer technology. After ambitious activities by a handful of researchers in some specialized laboratories, a methodologic inventory evolved to extract critical information about fossilized specimens, most of it preserved in the largely inaccessible interior as unrevealed anatomic structures. Many methodologies have become established but, for various reasons, access to both the actual and the digitized fossils is still limited. It is time for more transparency, for a glasnost in paleoanthropology. Herein are presented some answers to the question of how a high‐tech approach to anthropology can be integrated into a predominantly conservative field of research, and what are the main challenges for development in the future. Anat Rec (New Anat) 265:193–201, 2001. © 2001 Wiley‐Liss, Inc.
XQL and proximal nodes
Authors: Baeza‐Yates Ricardo , Navarro Gonzalo 
Published: August 2002

AbstractDespite the fact that several models to structure text documents and to query on this structure have been proposed in the past, a standard has emerged only relatively recently with the introduction of XML and its proposed query language XQL, on which we focus in this article. Although there exist some implementations of XQL, efficiency of the query engine is still a problem. We show in this article that an already existing model, Proximal Nodes, which was defined with the goal of efficiency in mind, can be used as an efficient query engine behind an XQL front‐end.
A design analysis model for developing world wide web sites
Authors: Ma Yan 
Published: August 2002

AbstractThis study applies reader‐response criticism to examine the relationship between and among designers, text, and users of the Galter Health Sciences Library Web site. It asks such questions as “How do Web site designers construct their subject?” or, “Whom do the web designers think their users are?” The study ascertains the intentions of the designers of the GHSL Web site; examines the meanings made by the users through interviews; compares the similarities and differences of designers' intentions with their organization of knowledge represented in the GHSL Web site; and compares the similarities and differences between the designers' intentions and views of the users.