bluuebunny/crossref_metadata_2025 huggingface dataset:
Prevalence of BK virus and JC virus in peripheral blood leukocytes and normal arterial walls in healthy individuals in China
Authors: Gu Zhi‐Yuan , Li Qi , Si Yi‐Ling , Li Xue , Hao Hao‐Jie , Song Hai‐Jing
Published: June 2003

Several studies have demonstrated that BK virus (BKV) and JC virus (JCV) establish latent infection in peripheral blood leukocytes (PBLs) of healthy individuals; however, the main populations studied are European. In this study, the prevalence of BKV and JCV DNA in PBLs from healthy adult individuals and umbilical cord blood from newborn children in China was detected by semi‐nested polymerase chain reaction (snPCR) followed by restriction enzyme analysis. The results suggest that the healthy adult Chinese population harbors BKV and JCV DNA in peripheral leukocytes. Overall, the prevalence of BKV and JCV DNA in PBLs of healthy adult individuals was 42.1% and 7.8%, respectively. The overall prevalence of BKV DNA was significantly higher than that of JCV DNA. None of the umbilical cord blood samples from newborn children were positive for BKV and JCV DNA. To understand further the target tissues involved in establishment of BKV and JCV latency in healthy individuals, the presence of DNA from both viruses was detected in normal arterial wall samples from 20 young trauma victims by the same method used for leukocyte DNA. BKV DNA was detected alone in 20% of samples tested; JCV DNA was not detected alone in any of the samples. DNA from both viruses was found in 5% of samples. This is the first report to show that normal arterial walls of healthy individuals may be another target site of latency for BKV and JCV. J. Med. Virol. 70:600–605, 2003. © 2003 Wiley‐Liss, Inc.
Measurement of EBV‐IgG anti‐VCA avidity aids the early and reliable diagnosis of primary EBV infection
Authors: Robertson Peter , Beynon Sandy , Whybin Ross , Brennan Catherine , Vollmer‐Conna Uté , Hickie Ian , Lloyd Andrew
Published: June 2003

Current serological methods for the diagnosis of Epstein‐Barr virus (EBV) infection still differentiate poorly between primary infection and reactivation. This is particularly true when IgG and IgM antibodies are present simultaneously and only a single serum sample is provided for analysis. The demonstration of the IgG avidity state has the potential to distinguish recent from past or reactivated infection. An analysis of the kinetics of avidity maturation of anti‐VCA antibodies in primary EBV infection was undertaken with longitudinally collected sets of sera from 28 well‐characterised EBV cases and in sera from 35 cases with previous EBV infection and recent primary infection due to HIV, CMV, or hepatitis A. Antibodies directed against the viral capsid antigen (VCA) and Epstein‐Barr nuclear antigen (EBNA‐1) were sought, using a commercial enzyme immunoassay (EIA). In parallel with standard IgG anti‐VCA detection, serum was incubated with 8 M urea to disrupt low‐avidity complexes to allow calculation of the percentage avidity. In cases with primary EBV infection, the mean avidity rose from 54% at 6 weeks to 82% by 28 weeks after the onset of symptoms, but remained lower than that of the control sera (96%). The addition of the avidity measurement improved the sensitivity of IgG and IgM anti‐VCA testing in diagnosis of primary EBV infection from 93% to 100%. The specificity of IgM anti‐VCA testing alone was poor, with 14 of 35 cases (49%) demonstrating false‐positive results, but it improved to 97% by the demonstration of high‐avidity IgG anti‐VCA. The combination of negative IgG anti‐EBNA and low‐avidity IgG anti‐VCA had a sensitivity and specificity of 100%. The routine addition of IgG anti‐VCA avidity estimation to diagnostic EBV serology is recommended. J. Med. Virol. 70:617–623, 2003. © 2003 Wiley‐Liss, Inc.
Congenital infection with human herpesvirus 6 variant B associated with neonatal seizures and poor neurological outcome
Authors: Lanari Marcello , Papa Irene , Venturi Valentina , Lazzarotto Tiziana , Faldella Giacomo , Gabrielli Liliana , Guerra Brunella , Landini Maria Paola , Salvioli Gian Paolo
Published: June 2003

Human herpesvirus 6 (HHV 6) has neurotropic and neuroinvasive properties. The virus has been found in the cerebrospinal fluid of many children with aseptic meningoencephalitis. Intrauterine transmission has been documented by HHV 6 DNA detection in cord blood specimens of apparently healthy newborns and in fetuses following spontaneous abortions. A patient is described with early neonatal afebrile seizures resulting from a congenital HHV 6 variant B infection disclosed by repeated detection of viral genome by polymerase chain reaction (PCR) in cerebrospinal fluid in the first days of life. At follow‐up, magnetic resonance imaging (MRI) studies disclosed hyperintensities in the periventricular white matter and basal ganglia, associated with cerebral atrophy. Further follow‐up at 18 months revealed poor neurological outcome with mild neurodevelopmental retardation, strabismus and hypertonia of legs. This report provides evidence of neurological involvement after HHV 6 vertical transmission, and the association with neurological sequelae. J. Med. Virol. 70:628–632, 2003. © 2003 Wiley‐Liss, Inc.
Enhanced mucosal and systemic immune responses following intravaginal immunization with human papillomavirus 16 L1 virus‐like particle vaccine in thermosensitive mucoadhesive delivery systems
Authors: Park Jeong‐Sook , Oh Yu‐Kyoung , Kang Min‐Jeong , Kim Chong‐Kook
Published: June 2003

To develop more potent and convenient mucosal human papillomavirus (HPV) vaccines, we tested the effect of thermosensitive mucoadhesive vaginal vaccine delivery systems on the local and systemic antibody responses to HPV 16 L1 virus‐like particles (VLP). HPV 16 L1 VLP expressed from recombinant baculovirus‐infected Sf21 insect cells were delivered in phosphate‐buffered saline (PBS) or thermosensitive mucoadhesive delivery systems, composed of poloxamers (Pol) and varying amounts of polyethylene oxide (PEO). Pol/PEO‐based vaginal vaccine delivery systems existed in liquid form at room temperature, but gelled at 37°C. The mucoadhesiveness of Pol/PEO‐based delivery systems increased with PEO, but the formulations with PEO higher than 1.0% were too viscous to be administered into the vagina. Vaccine vehicles affected the vaginal and salivary immune responses to HPV 16 L1 VLP intravaginally administered into mice. At 42 days after the first intravaginal immunization of HPV 16 L1 VLP with cholera toxin, vaginal and salivary IgA titers were the highest in the group given in Pol/PEO 1.0% vehicle followed by Pol/PEO 0.4% and PBS vehicles. Intravaginal coadministration of HPV 16 L1 VLP and cholera toxin in Pol/PEO 1.0% showed 31‐ and 39‐fold higher titers compared to the PBS‐based HPV 16 L1 VLP groups administered by intravaginal and intramuscular routes, respectively. Following intravaginal administration, Pol/PEO 1.0%, but not Pol/PEO 0.4%, showed significantly higher HPV 16 L1 VLP‐specific serum IgG titers as compared to the PBS vehicle. Our results indicate that the use of in situ‐gelling vaginal vaccine delivery systems with increased mucoadhesiveness would be beneficial for more effective induction of mucosal and systemic immune responses to intravaginally administered HPV 16 L1 VLP vaccines. J. Med. Virol. 70:633–641, 2003. © 2003 Wiley‐Liss, Inc.
Genetic and antigenic characterization of measles viruses that circulated in Korea during the 2000–2001 epidemic
Authors: Na Byoung‐Kuk , Shin Ju‐Mi , Lee Joo‐Yeon , Shin Gu‐Choul , Kim Yoon‐Young , Lee Jin‐Soo , Lee Jong‐Koo , Cho Hae‐Wol , Lee Hoan‐Jong , Rota Paul A. , Bellini William J. , Kim Woo‐Joo , Kang Chun
Published: June 2003

Despite the marked reduction in the incidence of measles in Korea by the introduction of measles vaccine, a large measles epidemic occurred during 2000–2001. During the epidemic, more than 55,000 measles cases were reported and at least 7 children were dead. In this study, we analyzed the genetic and antigenic properties of 15 measles viruses that isolated during the epidemic. Sequence analyses of entire hemagglutinin (H) and nucleoprotein (N) genes of the viruses indicated that all Korean isolates had a high degree of homology (>99.8%) when compared with each other. They differed from other wild‐type viruses by as much as 6.8% in the H gene and 6.5% in the N gene at the nucleotide level. The deduced amino acid variability was up to 6.4% for the H protein and up to 6.5% for the N protein. Phylogenetic analysis of nucleotide sequences and deduced amino acid sequences of the H and N genes revealed that all Korean viruses were grouped into the genotype H1. This strongly demonstrated that single genotype of measles virus has been circulated in Korea during the 2000–2001 epidemic. Plaque reduction neutralizing antibody titers against vaccine strains, Edmonston and Schwarz, and recently isolated Korean strains were measured using sera from vaccinees and recently infected children. Although sera of recently infected children demonstrated higher neutralizing antibody titers against wild‐type strains than against vaccine strains, both sera neutralized both strains and the reciprocal geometric mean titers (GMTs) were not significantly different against both strains. J. Med. Virol. 70:649–654, 2003. © 2003 Wiley‐Liss, Inc.
Slope clay‐with‐flints (biefs à silex) as indicators of Quaternary periglacial dynamics in the western part of the Paris Basin, France
Authors: Laignel B. , Quesnel F. , Spencer C. , Meyer R. , Lautridou J. P.
Published: June 2003

The lithology and distribution of the clay‐with‐flints occurring on slopes, called biefs à silex in French, suggests a twofold classification of these deposits according to slope angle. Biefs à silex formed as a solifluction deposit under Quaternary periglacial conditions during valley development. Two biefs à silex facies suggest two phases of development between 800 000 and 20 000 yr BP. Copyright © 2003 John Wiley & Sons, Ltd.
The loess and coversands of northern France and southern England
Authors: Antoine Pierre , Catt John , Lautridou Jean‐Pierre , Sommé Jean
Published: June 2003

Loess and coversands are widespread on either side of the English Channel. In southern England, loess is generally thin and discontinuous, but locally reaches thickness of about 4 m in east Kent. Coversands occur mainly in areas well north of the Channel, such as parts of East Anglia and the southern side of the Bristol Channel. Most of the loess and coversand deposits in southern England date from the Late Devensian cold stage (marine oxygen isotope stage (MOIS) 2), but there are also a few localised patches of older (mainly MOIS 6 and 12) loess, which are the dissected remnants of originally more extensive covers. In France loess is widespread and locally very thick (up to 12 m), especially in northern and northeastern France. In Normandy and in the Somme basin some long records indicate that accumulation began at the end of the Lower Pleistocene, at about 900 ka. Nevertheless the main accumulations of typical calcareous loess are related to the Upper Weichselian and Upper Saalian stages (MOIS 2 and end of MOIS 3 and MOIS 6). Indeed, before about 160–170 ka, loess deposition was generally restricted to special sediment traps such as fluvial and marine terraces exposed to the east or northeast. These older deposits are characterised by more sandy facies derived from local fluvial sources (mainly by northwest to north‐northwest winds). Coversands occur locally along the coast of the Mont Saint‐Michel bay, and over the northern part of the Seine estuary near Le Havre. The main differences in thickness and extent of the loess deposits between southern England and northern France are linked to their location in relation to the source areas (Channel and North Sea), to ice sheets, and to the main wind directions (northwest to north‐northwest in France and western England but northeast in eastern England). Copyright © 2003 John Wiley & Sons, Ltd.
Holocene coastal evolution and sea‐level change on the southern coast of England: a review
Authors: Waller Martyn P. , Long Antony J.
Published: June 2003

Data collected recently from select areas within the eastern, central and western English Channel are used to reconstruct the Holocene evolution and sea‐level history of the southern coast of England. Rapid sea‐level rise in the early Holocene produced a ubiquitous vertical and lateral expansion in the marine influence. From ca. 6800 cal. (calendar) yr BP the rate of sea‐level rise declined and a shift from minerogenic to organogenic sedimentation is also widely recorded. A further decline in the rate of sea‐level rise occurred in the late Holocene, during which time the eastern and central English Channel experienced coastal inundation and a return to minerogenic sedimentation. Explanations for this apparent contradiction include the effects of this decline on the accumulation of minerotrophic peat and changes in sediment supply. Sea‐level index points from the eastern Channel generally plot below those from the central and western Channel, indicating differential crustal movement, although sediment compaction and tidal range also may be responsible for apparent altitudinal variation between these areas. Despite an increase in the quantity and quality of the data available from this region over the past 20 yr these, and a number of other important issues, require further clarification. Copyright © 2003 John Wiley & Sons, Ltd.
Holocene and modern sediments in the Seine estuary (France): a synthesis
Authors: Lesueur P. , Lesourd S. , Lefebvre D. , Garnaud S. , Brun‐Cottan J. C.
Published: June 2003

This synthesis of numerous studies on the Holocene and modern sediments in the macrotidal setting of the Seine estuary demonstrates their overall evolution. In common with a number of estuaries, the lower Seine was an incised valley during the Weichselian glacio‐eustatic sea‐level fall, and infilling occurred during the subsequent lowstand, the Holocene sea‐level rise and the late Holocene stillstand. In the upper estuary, above the basal gravel bed, fluvial freshwater deposits filled the valley. Next, fine sand and silts invaded the estuary upstream to Rouen; the sequence ends in loam, resulting from an increase in the supply of sediment to the fluvial system. In the upper estuary, anthropogenic deepening of the modern channel results in erosion of the Holocene sediments; the only bedforms are thin and narrow sand sheets and some rare megaripples. In the lower estuary, above the Weichselian basal gravel, the Holocene wedge records the change from a transgressed fluvial setting (i.e. gravel beds) to an open estuarine environment (i.e. tidal delta). The modern Seine estuary has been progressively infilled by marine sands and silts. Now silts and clays supplied during high river flows accumulate at the outlet, and offshore sands and gravel of the eastern Bay of the Seine are temporarily covered with veneers of mud. These freshly deposited muds (i.e. mud patches) are periodically partly reworked by waves and strong tidal currents, but silting of the inner shelf is noticeable. Copyright © 2003 John Wiley & Sons, Ltd.
The Quaternary Channel River: seismic stratigraphy of its palaeo‐valleys and deeps
Authors: Lericolais Gilles , Auffret Jean‐Paul , Bourillet Jean‐François
Published: June 2003

Based on the interpretation of geophysical data (very high resolution seismic data combined with EM1000 swath bathymetry), this paper reviews the history of the Channel River throughout the late Cenozoic. New evidence does illustrate how the interplay of tectonics, eustacy and climate have influenced this northwest European drainage system.

The concepts of sequence stratigraphy allow the subdivision of the sedimentary record into depositional sequences bounded by unconformities, resulting from globally synchronous sea‐level changes. However, the recognition of eustatic sea‐level changes in a cold climate environment is very difficult, because of the interplay of additional phenomena such as glacio‐isostatic sea‐level changes with glacio‐eustatic changes. For our interpretation, it was necessary to adjust these concepts with the relative importance of geomorphological processes determining the behaviour of rivers and steering their evolution.

The foundations of the modern drainage system were laid after the Oligocene Channel inversion. In general these early rivers occupied shallow valleys. The Pleistocene cold climates resulted in fluvial incision. Through time, the Channel River has adopted a drainage system that can be divided into three parts: (i) the drainage basin comprising the Southern Bight, the eastern Channel and the London and Paris basins, (ii) the river zone itself, which begins at the Cotentin peninsula and passes through the Hurd Deep, before reaching the continental shelf‐break in the Celtic Sea, (iii) the depositional basin represented by the Celtic Banks complex and by the deep sea fans, located at the foot of Shamrock and Black Mud canyons. During important lowstands (marine oxygen isotope stages 22, 16, 10, 6 and 2), the Channel River seems to have reached the shelf‐break, as indicated by the internal structure of the banks. Copyright © 2003 John Wiley & Sons, Ltd.
The Pleistocene rivers of the English Channel region
Authors: Antoine Pierre , Coutard Jean‐Pierre , Gibbard Philip , Hallegouet Bernard , Lautridou Jean‐Pierre , Ozouf Jean‐Claude
Published: June 2003

The Pleistocene history of river systems that enter the English Channel from northern France and southern England is reviewed. During periods of low sea‐level (cold stages) these streams were tributaries of the Channel River. In southern England the largest, the River Solent, is an axial stream that has drained the Hampshire Basin from the Early Pleistocene or late Pliocene. Other streams of southern England may be of similar antiquity but their records are generally short and their sedimentary history have been destroyed, as in northern Brittany, by coastal erosion and valley deepening as a consequence of tectonic uplift. In northern France, the Seine and Somme rivers have very well developed terrace systems recording incision that began at around 1 Ma. The uplift rate, deduced from the study of these terrace systems, is of 55 to 60 m myr−1 since the end of the Early Pleistocene. Generally the facies and sedimentary structures indicate that the bulk of the deposits in these rivers accumulated in braided river environments under periglacial climates in all the area around the Channel. Evolution of the rivers reflects their responses to climatic change, local geological structure and long‐term tectonic activity. In this context the Middle Somme valley is characterised by a regular pattern in which incision occurs at the beginning of each glacial period within a general background of uplift. Nevertheless the response of the different rivers to climatic variations, uplift and sea‐level changes is complex and variable according to the different parts of the river courses. Copyright © 2003 John Wiley & Sons, Ltd.
Fillers design and best use: recent trends and basic questions
Authors: Van Damme Henri , Burr Alain
Published: June 2003

This paper is a discussion of a few selected topics or trends in recent research literature which raise fundamental issues in our understanding of the way fillers improve the properties of polymers. A first topic is the now well‐established experimental and theoretical evidence that the Tg and the molecular mobility in free standing or supported films are modified over a much larger thickness than was previously thought. Considering their enormous interface area, this introduces a new look to the remarkable reinforcement effect obtained in delaminated clay nanocomposites. On the other hand, the reason why, in spite of their extraordinary mechanical properties and their very large surface area, carbon nanotubes, with their fibre‐like morphology, are still far from giving the same reinforcement, is still an open question. A second topic to be mentionned is the development of hybrid materials and biomimetic approaches which, due to very small scale of the organic‐inorganic heterogeneities which can be achieved, raises questions on the phase concept and points to the need for new theoretical approaches of the mechanical properties of these materials. Finally, a third topic is the control of the filler particles distribution in the matrix. The general theory of random diphasic media permits to define several types of “good” dispersions in terms of disordered distributions, according to the correlations of the particles positions in a matrix. This raises two problems, which are briefly discussed: (i) Are we able to define the type of dispersion we want? (ii) Is it relevant for modifying the properties?
Effect of fillers on the properties of recycled polymers
Authors: La Manila Francesco Paolo
Published: June 2003

The main problems in post‐consumer plastics recycling are due to the degradation undergone during lifetime and during processing steps. Moreover, for heterogeneous recycling, the incompatibility among the different polymeric phases give rise to secondary materials with low mechanical and thermomechanical properties. The properties‐reprocessing relationships are an important tool for determining not only the properties of the recycled polymers but also the strategies to apply (processing conditions, stabilisers, fillers, compatibilizers, etc) in order to obtain recycled polymers with good mechanical properties.

In this work the effect of adding inert fillers and modifier agents to recycled post‐consumer plastic materials is discussed. The addition of inert fillers of different nature can strongly improve the rigidity and thermomechanical resistance of these secondary materials. The addition of modifier agents improves the deformability and the impact strength of the recycled plastics. The beneficial effect of inert fillers and modifier agents is particularly important in the case of commingled post‐consumer plastics.
Aggregation of particulate fillers: factors, determination, properties
Authors: Móczó János , Fekete Erika , László Krisztina , Pukánszky Béla
Published: June 2003

The aggregation tendency of 11 different CaCO3 fillers with widely differing particle sizes was studied in polypropylene (PP) composites. The fillers were characterized by different techniques in powder form and in suspension. Homogenization and sample preparation were carried out by extrusion and injection molding, or in an internal mixer and compression molding, respectively. Thin slices were prepared from the composites and the relative area of aggregates was determined by image analysis. Tensile and fracture properties were studied as a function of filler content. The results proved that the extent of aggregation increases with decreasing particle size and increasing filler content. Surprisingly, extruded and injection molded samples contained more aggregates than those prepared by homogenization in an internal mixer followed by compression molding. Good agreement was found between the powder properties of the fillers and their performance in the composites. Deviations from the general tendency indicate that some factors, which were not accounted for in the study, also influence aggregation and composite properties.
Silica and carbon black reinforcement of natural rubber
Authors: Bokobza Liliane , Rapoport Olivier
Published: June 2003

Recent investigations on filled natural rubber are reported. They include a mechanical characterization as well as a molecular analysis based on measurements on chain orientation. It is demonstrated that, at intermediate strains, the increase in the moduli can be explained by the inclusion of rigid particles in the soft matrix and from molecular interactions between the rubber and the filler. These interactions can be evaluated by equilibrium swelling and by orientational measurements. With regard to the unfilled formulation, carbon black‐ and silanized‐filled natural rubber exhibit increases in the cross‐linking density ascribed to filler‐polymer links while a large decrease in the orientational level, evidenced by birefringence and by infrared dichroism, is observed when silica is added without any couplig agent.
Polymerization‐filled composites and nanocomposites by coordination catalysis
Authors: Dubois Philippe , Alexandre Michaël , Jérôme Robert
Published: June 2003

Polyolefinic microcomposites and layered silicate nanocomposites were prepared by the in‐situ polymerization of ethylene (and α‐olefin) via the so‐called polymerization‐filling technique. Various fillers with either basic, acidic, metallic or carbonaceous surface, as well as non‐modified clays such as montmorillonite and hectorite, were first treated by trimethylaluminum‐depleted methyialuminoxane before being contacted by a titanium or zirconium‐based metallocene catalyst. The (nano)composite was formed by addition and polymerization of ethylene (and α‐olefin). This technique makes possible the complete encapsulation of every filler particle within the (co)polyolefinic matrix ranging from thermoplastics to elastomers. The so‐obtained (nano)composites, often coined as “homogeneous” (nano)composites, exhibit improved mechanical properties, as compared to more conventional melt blends for a same filler content.
Synthesis and characterization of functional chemically modified silica fillers
Authors: Tertykh Valentin , Yanishpolskii Victor , Bol'bukh Yulia
Published: June 2003

Elaborated methods of synthesis of chemically modified silicas with grafted silicon hydride and amino groups are analyzed. Experimental results on use of modified silicas with bonded amino groups as fillers of carboxyl‐containing rubbers and epoxy resins are reported. It was shown that modified silica fillers with grafted silicon hydride groups could be applied for carrying out processes of catalytic solid‐phase hydrosilylation of 2‐hydroxyethylmethacrylate and some other functional olefins.
Mica as a filler for PET scrap/oxazoline functionalized polyethylene blends
Authors: Jeziórska Regina
Published: June 2003

A series of mica filled PET scrap/PE‐g‐ROM blends was studied in a chemical modification involving reactive extrusion with a ricinoloxazoline maleinate. Studies were conducted concerning mechanical properties (flexural and impact strength), thermal properties (DSC and Vicat softening temperature) and flame retardancy. The phase morphology of the blends was of interpenetrating network (IPN) type according to SEM results. Mica filled blends offer good mechanical properties, reduced flammability and increased Vicat point. The composition with 30% of mica gives the best properties and efficiency in reducing the rate of burning.
Tailored interfaces in nanocomposites
Authors: Le Pluart L. , Duchet J. , Sautereau H. , Gérard J.F.
Published: June 2003

Different kinds of clays based on sodium montmorillonite have been modified i) by cationic exchange of alkylammonium ions and ii) by covalent grafting of organosilane. We have prepared organophilic clays with different gallery heights (due to alkylammonium ions with alkyl chain length varying from 8 to 18 carbon atoms) and with a specific functionalisation (due to the organosilane). We have generated organoclays with different kind of organic layer properties: ionically bonded or physically adsorbed alkylammonium ions and covalently grafted organosilane. These different organoclays have shown various specific behaviours when dispersed in monomers or in a reactive mixture, proving the influence of the surfactant on the nanocomposite final properties.
Modification of the rheological properties of polyurethanes by adding fumed silica: influence of the preparation procedure
Authors: Pérez‐Limiñana M.A. , Torró‐Palau A. , Orgilés‐Barceló A.C. , Martín‐Martínez J.M.
Published: June 2003

The way of addition of fumed silica determined the rheological properties of polyurethane (PU) adhesives. The higher the shear rate during preparation of fumed silica containingPU adhesives, the higher viscosity and improved plasticity and thixotropy in the solutions. The improved properties of these adhesive solutions were ascribed to the creation of interactions between the silanol groups on the fumed silica, the polar groups in the soft segments of the polyurethane and/or the solvent. However, the way of incorporate the fumed silica in the polyurethane did not affect the rheological properties of fumed silica‐PU composites (obtained by solvent removal from the solutions), indicating the key role of the solvent in the rheology of PU adhesive solutions.
Effect of coal on the rheological and mechanical properties of epoxy matrix
Authors: Kurzeja Lidia , Szeluga Urzula , Galy Jocelyne , Sautereau Henry , Issartel Nathalie
Published: June 2003

An experimental study was conducted to investigate the effect of coal used as a new type of filler in epoxy networks. For this purpose two series of epoxy composites with different coal weight fraction were studied and their thermo‐mechanical properties were characterized. The work demonstrated that coal‐filled epoxy networks show a typical behavior of a particulate filled material and follows the theoretical models already used.
Filler‐filler interaction and filler‐polymer interaction in carbon black and silica filled ExxproTM polymer
Authors: Wong W.K. , Ourieva G. , Tse M.F. , Wang H.C.
Published: June 2003

Due to the presence of reactive benzylic bromide, Exxpro has much better interaction with silica in comparison with polybutadiene as demonstrated by the high bound rubber level. The better silica/Exxpro interaction is further substantiated by the low degree of filler network formation in comparison to that observed for silica filled polybutadiene as demonstrated by the much smaller deviation of low strain shear modulus from the Guth‐Gold relationship for the silica filled Exxpro. Silane treatement of silica reduces filler network formation in polybutadiene but has only slight effect on silica filled Exxpro indicating that even without silane treatment silica already disperse well in Exxpro due to high degree of filler/polymer interaction. This result in silica filled Exxpro compound exhibiting better processability (lower shear viscosity) as well as dynamic performances for tire applications (higher tan δ at −20 and 0°C, lower tan δ at 60°C). We speculate that nucleophilic substitution reaction takes place between benzylic bromide and surface hydroxide group of silica.
Analysis of the viscoelastic behaviour of silica filled rubber: prediction of the interphase properties
Authors: Mélé Patrice , Da Silva Claude , Marceau Sandrine , Brown David , De Puydt Yves , Albérola Nicole Dominique
Published: June 2003

The aim of this work is to analyse the influence of both silica content and the presence of a silane coupling agent on the viscoelastic behaviour of silica filled rubber. It is well‐known that changes in the dynamic mechanical properties of filled rubber could result from either the mechanical coupling between phases and/or interface effects. Micro mechanical modelling, taking morphological analysis into account, will be used to separate these two effects and allows us to assess the actual properties of the polymer close to the silica surface.
Reactively processed high performance impact modified polypropylene/magnesium hydroxide composites: interfacial studies
Authors: Liauw Christopher M. , Khunová Viera , Lees Graham C. , Rothon Roger N.
Published: June 2003

The interphase structure development in impact modified PP (IMPP)/magnesium hydroxide (Mg(OH)2) composites reactively processed with 1,3‐phenylene dimaleimide (BMI), in conjunction with a fatty acid amide/ester based lubricant, has been investigated using a three factorial experimental design. Insoluble matrix content, DSC and IR spectroscopic responses indicated that the lubricant preferentially adsorbed on the filler and thus shifted the locus of BMI addition reactions away from the filler surface, towards the bulk matrix. This prevented formation of an effective interphase structure in which the impact modifier phase encapsulating the filler was strongly bonded to the surrounding, chain extended and branched, polypropylene phase.
Using clay in PA‐based intumescent formulations. Fire performance and kinetic parameters
Authors: Dabrowski François , Le Bras Michel , Delobel René , Gilman Jeffrey W. , Kashiwagi Takashi
Published: June 2003

The improved fire performance of polyamide‐6 clay nanocomposite compared with polyamide‐6 are correlated with their degradation kinetic parameters. Moreover substituting polyamide‐6 by polyamide‐6 clay nanocomposite in an intumescent blend enables to improve its fire properties. Once again, the improved fire performance can be correlated with the kinetic degradation parameters. The advantages of using nano‐dispersed clay are shown.
Investigations of fire retardant properties of polypropylene‐clay‐nanocomposites
Authors: Wagenknecht Udo , Kretzschmar Bernd , Reinhardt Gerd
Published: June 2003

Polypropylene‐clay nano composites were prepared by compounding using a masterbatch technology. The burning behaviour of the nanocomposites was tested. The nanocomposites show fire retardant effects. The effects were discussed by microscopy investigations of the ash and by rheological behaviour of the composites.
Nickel coated mica for conductive compounds
Authors: Gilbert M. , Kandasubramanian B.
Published: June 2003

It has been shown that nickel coated mica will function as a conductive filler in ABS compounds. The coating process has been optimised by investigation of PdCl2 (catalyst) concentration, coating temperature and pH and activator. Using a coating temperature of 90°C and a pH of 5, conductive mica powders coated with thin uniform layers of nickel have been produced.
The effect of compatibilizing and coupling agents on the mechanical properties of glass bead filled PP/PET blends
Authors: Arencón David , Maspoch Maria Lluïsa , Velasco José Ignacio
Published: June 2003

PP/PET blends (95/5) filled with 50% by weight of glass beads were prepared and studied at morphological and mechanical level, and compared with its analogous samples of glass bead‐filled PP. The influence of a compatibilizing agent (maleic anhydride grafted polypropylene) and different silane coupling agents was analysed. It has been found that PET embeds glass bead surface independently on the silane coupling agent employed. Addition of MAPP in PP/PET blends leaded to tensile strength values similar to those of unfilled PP, but rupture takes place in a brittle manner.
Preliminary studies on the surface layer of starch
Authors: Bieliński Dariusz , Pysklo Leszek , Dul Jan , Ślusarski Ludomir , Janowska Grażyna , Lewandowicz Grażyna
Published: June 2003

Characterization of the surface layer of starch powder, originated from potato or maize, was carried out applying various experimental techniques: Fourier‐transformed infrared internal reflection spectroscopy (FTIR‐IRS), inverse gas chromatography (IGC) and scanning electron microscopy (SEM). The main kinds of starch were studied as potential fillers for rubber and results discussed in terms of factors requiring modification to improve starch miscibility and activity towards rubber. Starch of high amylopectine content shows surface enrichment with amylose what makes crystallinity of the surface layer higher than in bulk of the material. Particles of the both kinds of starch have very smooth surface (morphological index, Im = 0.995), highly resistant to its geometrical development. Dispersive component of the surface energy of starch was found to be similar to that of low energy polymers (γsd = 32.5 mJ/m2 at 23°C) and its surface to be of electron‐donor character.
Processing of polypropylene ‐ clay hybrids
Authors: Boucard S. , Duchet J. , Gérard J.F. , Prele P. , Gonzalez S.
Published: June 2003

Polypropylene compounds containing organophilic layered silicates were prepared by means of melt extrusion at 180°C. We have studied the effect of the coupling agent on morphology development and mechanical properties. We are convinced of the importance of both the chemistry and the process conditions to elaborate nanocomposites with optimized properties.
Silica nanofillers ‐ preparation and characterization
Authors: Jesionowski Teofil
Published: June 2003

Studies were conducted on formation of monodisperse silicas from sodium metasilicate and hydrochloric acid solutions in emulsion medium. Non‐ionic surfactants were used as emulsifiers. Physicochemical parameters of the precipitated silicas were determined, including particle size, polydispersity, structure and shape of particles. Moreover, specific surface area (BET) and porosity were characterized. Silica of optimum physicochemical parameters, i.e. of the ideally spherical particle shape, monodisperse character was obtained using a homogenization technique during precipitation and Rokafenol N‐3/N‐6 surfactant mixture as emulsifiers.
Fumed silica synthesis. Influence of hydrogen chloride on the fumed silica particle formation process
Authors: Khavryutchenko Alexey V. , Khavryutchenko Vladimir D.
Published: June 2003

Interaction of silicon dioxide molecule up to the small silica protoparticle and primary particle formation, and influence of hydrogen chloride (HCl), water (H2O) and inert molecules (nitrogen N2) “under flame condition” and “after cooling” on structure and properties of fumed silica were investigated by quantum‐chemical simulations. An attempt to give definition of surface concept on atomic level was made.
Inverse gas chromatography in the examination of modified fillers
Authors: Voelkel Adam
Published: June 2003

Dispersive and specific surface properties of silica modified with silanes, titanium and zirconium coupling agents were characterised by means of inverse gas chromatography. This method was also successfully applied in the examination of raw and modified silicates.
Thermomechanical degradation of filled polypropylene
Authors: La Mantia F.P. , Tzankova Dintcheva N.
Published: June 2003

The main problem in post‐consumer plastics recycling is due to the thermomechanical stress acting on the melt during the reprocessing operations. The macromolecules break because of the temperature and of the mechanical stress. The extent of degradation is then correlated to the level of mechanical stress which, in turn, is proportional to the viscosity of the melt. The presence of fillers increases the viscosity of the polymers and then it is expected that the level of thermomechanical degradation of these systems is larger than that of the unfilled material.

In this work the thermomechanical degradation kinetic of a polypropylene sample is investigated as a function of the calcium carbonate content. It is shown that the decrease of viscosity, that is the decrease of molecular weight, is directly related to the increase of viscosity due to the filler content. The worsening of the mechanical properties are consistent with the change of viscosity.
Characterisation of filled and recycled PA6
Authors: Maspoch Maria Lluïsa , Ferrando Haritz Eder , Velasco José Ignacio
Published: June 2003

Filled PA6 are important representatives of engineering plastics used in automotive components. Nowadays, the demand of plastic recycled grades is increasing in this branch of industry but polymer recycling can undergo thermomechanical degradation processes with the results of a poor secondary material, regarding its properties. In this paper an investigation of thermal, mechanical (tensile, flexural and impact tests) and rheological properties of a sample of recycled and filled PA6, is reported as a function of the number of reprocessing operations (3 times) and of the fraction of recycled material (15, 30 and 50%) added to the virgin material. Recycled PA6, used in this study, comes from fibre grade production waste. Material was filled with 20% glass beads and 10% glass fibre, according to the specifications of the application, mainly to obtain a lower shrinkage in the end product. This work also shows that the mineral fraction, not being degraded during the injection process, allows better recyclability to the filled material. The properties of the recycled material remain below the virgin, and the best combination of both appears to be the mixture with 30w.% recycled fraction, which shows a lost of properties similar to 3 reprocessing operations.
The use of Flory‐Huggins parameters to characterization of polymer/filler interactions
Authors: Milczewska Kasylda , Voelkel Adam , Jeczalik Jerzy
Published: June 2003

Any quantitative information on the strength of interactions between inorganic filler and polymer is substantial for the future application of the composite. The magnitude of adhesion of two phases may be deduced from results collected by various experimental techniques. Inverse gas chromatography is very simple and precise method.

Authors propose to express the magnitude of modified filler/polymer interactions by Flory‐Huggins χ23 parameter. We investigated polyether‐urethane/3‐mercaptopropyltrimethoxysilane systems containing different amount of filler (5, 10, 20 wt%).

Moreover, information on the physico‐chemical status of oligomer and modified silicas were presented with the use of the following parameters:

• solubility parameter δ2 and its components describing properties of the polymer layer;

•Flory‐Huggins parameter χ12 which describes polymer‐solute or filled polymer‐solute interactions.

Subscripts 1, 2, 3 and m refers to solute, polymer, filler and polymer/filler mixture, respectively. Pure, low molecular weight, volatile test solutes were selected and injected into a chromatographic column.

The influence of the IGC experiment, temperature, the content of modified silica and the nature of test solute on the evaluated parameters are presented and discussed.
New type of inorganic filler with a core‐shell structure
Authors: Owczarek Magdalena , Zaborski Marian , Paryjczak Tadeusz , Boiteux Gisele , Gain Olivier
Published: June 2003

We tried to use a new kind of filler with “core‐shell” structure as a crosslinking agent for carboxylated butadiene‐acrylonitrile rubber. We thought that the substance would be better dispersed in the polymer matrix than zinc oxide. Silica (ZnO/SiO2) whose surface was modified with amorphous zinc oxide from zinc nitrate was used. Its properties were investigated using gas chromatography.

Finally we obtained unconventional networks containing ionic and complex bonds (as a result of reaction of elastomers' functional groups i.e. carboxyl groups with the appropriate neutralizing agent as metal oxide). Ionic clusters were formed in vulcanizates which influenced the mechanical properties and crosslinking efficiency. We confirmed the presence of these unconventional bonds by IR spectroscopy and DMTA analyses.
Synthesis of silica in elastomer's matrix
Authors: Pietrasik Joanna , Zaborski Marian , Boiteux Gisele , Gain Olivier
Published: June 2003

We tried to synthesise silica's fillers in polar and nonpolar elastomers. Di‐, tri‐ and tetraalkoxysilanes were used as a precursor of silica. Such functionality allowed us to obtain a filler with different ratio of crosslinking. We could expect some interactions between elastomer and silanes, which contained additional functional groups. We investigated vulcanizates by using the following methods: crosslink density in toluene and 10% solution of ethylenediamine in toluene, mechanical properties, IR microscopy, DMA. It appeared that alkoxysilanes influenced advantageously on elastomers and properties.
Synthesis and modification of fillers with derivatives of benzoic acids
Authors: Tyburczy Michał , Zaborski Marian , Baryń Włodzimierz
Published: June 2003

The subject of this research work was an effect of liquid crystals on the properties of filled elastomer systems. Both commercially available and own synthesized liquid crystals were used. The elastomer was ethylene‐propylene rubber, while precipitated silica and calcium carbonate were used as fillers. The liquid crystals were deposited on the surface of the fillers from solution. Their effect on the mechanical properties of the vulcanizates was studied.
Comparative characteristics of local and foreign bentonites
Authors: Wieczorek Michał , Krysztafkiewicz Andrzej , Jesionowski Teofil
Published: June 2003

Comparative analysis was performed of local bentonites of SPECJAL EXTRA U and IZOL types, produced by Zakłady Górniczo‐Metalowe Zębiec, and of LT type bentonite, produced by Rheox company. Principal physicochemical properties of the bentonites were established, including bulk density, capacities to absorb water, dibutyl phthalate and paraffin oil and their sedimentation rates in water, xylene and gasoline were estimated. Bentonite morphology was examined using scanning electron microscope (SEM). Moreover, particle size distribution, BET surface area and zeta potential were determined.
Elasticity of fractal filler networks in elastomers
Authors: Klüppel Manfred
Published: June 2003

The role of filler networking in the elastic properties of elastomer composites is investigated by means of a fractal approach to filler aggregation in high viscosity media and a linear elastic model of flexible chains of filler particles. The filler netwok is described by a space‐filling configuration of fractal filler clusters, resulting from a kinetic cluster‐cluster aggregation (CCA) process. The elastic modulus of the filler network is shown to fulfil a scaling relation with respect to filler concentration. The universal value 3.5 of the elasticity exponent reflects the fractal nature of the filler network. Experimental results on various elastomer composites with conventional‐ and model fillers (microgels) demonstrate that a corresponding scaling prediction for the small strain modulus is well fulfilled.
Cavitation and cavity‐free deformation of filled crystalline polymer systems
Authors: Galeski Andrzej , Bartczak Zbigniew
Published: June 2003

Main mechanisms of tough response of polymers are described. In heterogeneous polymer systems due to mechanical misfit between heterogeneities and the matrix a high negative pressure (tri‐axial stress) is generated. The excessive negative pressure is the main reason of material cavitation. Cavitation appears to be another mechanism of tough response of the material to loading. Cavitation is a massive phenomenon in crystalline polymers and in all filled polymers. Cavitation itself does not consume much energy but allows for further toughening by activating other mechanisms. Examples of polypropylene filled with chalk modified by liquid, rubber and mineral filled polypropylene and syndiotactic polypropylene filled with chalk are described. Modes of deformation with significant compressive component of stress prevents for cavitation. Materials deformed in a cavity‐free manner show much higher strength. It is pointed out that high polymer crystal anisotropy is necessary for the formation of a network of easy crystallographic slip in the unusual toughening of highly filled polymers observed recently. An example of syndiotactic polypropylene filled with submicro‐chalk particles is presented.
Charge carrier transport in heterogeneous conducting polymer materials
Authors: Kryszewski Marian , Jeszka Jeremiasz
Published: June 2003

The similarities of conductivity mechanisms of composites and nanocomposites and doped conjugated polymers that are also characteristic of specific heterogeneity are discussed. It is shown that the formulae developed to account for internal heterogeneity of conductive polymers can be applied also for polymer composites in spite of low overall content of the conductive phase. For fully organic nanocomposites (reticulate doped polymers) showing metal‐like conductivity and a crossover temperature effective contribution of metallic phase is estimated. Examples of different properties of nanoparticles forming conducting networks as compared with the bulk crystals are discussed.