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Filler Concentration (filler + concentration)

Distribution by Scientific Domains

Polymers and Materials Science	87%

Selected Abstracts

Quality inspection in polymer processing by a thermophysical handy tester

HEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 6 2006
Yasuyuki Koshikawa
Abstract This paper presents the applicability of a thermophysical handy tester for quality inspection and diagnostic technique such as in situ measurement of polymeric resin products. Influence of crystallinity known as a rating factor of quality, or filler concentration upon thermal conductivity is determined for the case of unsaturated polyester resin products by using the tester. Consequently, good correlations between the thermal conductivity and the crystallinity or the filler concentration are certified. The variation or the distribution of thermal conductivity of products molded under various conditions can be detected nondestructively using the tester. As an example, the thermal conductivity distribution around the forming gate is demonstrated, indicating the density-uniformity of the resin product. © 2006 Wiley Periodicals, Inc. Heat Trans Asian Res, 35(6): 421,433, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20124 [source]

Advanced Calcium Copper Titanate/Polyimide Functional Hybrid Films with High Dielectric Permittivity

ADVANCED MATERIALS, Issue 20 2009
Zhi-Min Dang
A functional hybrid film with high dielectric permittivity and good thermal stability is obtained using calcium copper titanate as filler in a polyimide polymer matrix. The giant dielectric permittivity of the filler and its semiconducting characteristics impart good dielectric properties to the hybrid films. A dielectric permittivity high as 49 is achieved at a 40,vol% filler concentration at 102,Hz. [source]

Composites of rigid polyurethane foam and cellulose fiber residue

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010
M. C. Silva
Abstract Rigid polyurethane composite foams were prepared with cellulose fibers as a filler. The cellulose fibers were an industrial residue of blanched cellulose pulp production. The influence of the cellulose fiber concentration on the structural, thermal, mechanical, and morphological properties of the foams was investigated. We also studied the influence of the cellulose fibers on the foam's resistance to fungal attack by placing a suspension of known fungus in contact with the surface of the foam and following the morphological evolution as a function of time (for 60 days). The increase in the cellulose filler concentration in the foams, up to 16% w/w with respect to the polyol, changed their properties as follows: (1) the cell size decreased, (2) the thermooxidative stability and mechanical properties remained approximately constant, (3) the thermal conductivity decreased slightly, and (4) fungal growth was observed. Therefore, a cellulosic fibrous industrial residue was rationally valorized as a filler in classical rigid polyurethane foams; this yielded materials with mechanical resistance and a susceptibility to fungi in a wet environment. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source]

Melt mixing of carbon fibers and carbon nanotubes incorporated polyurethanes

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008
Shahrul Azam Abdullah
Abstract Polyurethane composites filled with carbon fibers (CF) and carbon nanotubes (CNT) were prepared by mixing and injection molding, and its mechanical as well as their thermal properties were investigated. Dynamic mechanical analysis (DMA), thermogravimetry analysis (TGA), and thermal conductivity tests were done, and the properties were evaluated as a function of the filler concentration. The storage modulus of the composites increased with fillers concentration, which also mean the increase of the stiffness, suggest a good adhesion between the polyurethane matrix and the fillers. Addition of more CF and CNT to the composites broadened and lowered the peak of tan , specifies that the polyurethane composite became more elastic because there is a good adhesion between the fillers and the matrix. The addition of carbon fillers improves the thermal stability of the polyurethane. The inclusions of CNT show a better thermal stability when compared with CF. The addition of carbon fillers also increased the thermal conductivity of the polyurethane composites. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source]

Glass Transition Temperature Depression at the Percolation Threshold in Carbon Nanotube,Epoxy Resin and Polypyrrole,Epoxy Resin Composites

MACROMOLECULAR RAPID COMMUNICATIONS, Issue 5 2005
Sophie Barrau
Abstract Summary: The glass transition temperatures of conducting composites, obtained by blending carbon nanotubes (CNTs) or polypyrrole (PPy) particles with epoxy resin, were investigated by using both differential scanning calorimetry (DSC) and dynamical mechanical thermal analysis (DMTA). For both composites, dc and ac conductivity measurements revealed an electrical percolation threshold at which the glass transition temperature and mechanical modulus of the composites pass through a minimum. DC conductivity, ,dc, as a function of the conducting filler concentration of the CNT, (,) and PPy, (,) epoxy resin composites. [source]

Microwave absorption of ferrite powders in a polymer matrix

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 5 2006
S. Kolev
Abstract The object of this work is to investigate the microwave absorbing properties of nanocomposite bulk samples. As filler we used magnetite with different particle size in a silicone rubber matrix and investigated the influence of the filler concentration and particle size in the polymer matrix on the microwave nonlinearity in a large frequency range (1 ÷ 13 GHz). We found that the intensity and the frequency at the reflection loss minimum depend on the particle size and particle concentration of magnetite in the samples. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

A nonlinear theoretical model for prediction of mechanical behavior of particulate composites and experimental verification of the model predictions

POLYMER COMPOSITES, Issue 7 2010
A. Ramazani S.A.
A model for prediction the stress-strain behavior of particulate composite over wide ranges of filler concentration and composite deformation has been developed through combination of Anderson's and Yilmizer's model. The constitutive equations are extracted from first law of thermodynamic and nonlinear dilatational effects which are produced by filler-matrix debonding process. In addition to nonlinear behavior that has been resulted by filler-matrix debonding and was presented by Yilmizer, the formation and growing of void or cavitations has been also introduced in this model, whereas Anderson's model, most important reason for deviation of linear behavior is filler-matrix debonding and has been indicated by change of modulus. Model predictions for effects of the filler concentration and its particle size and particle size distribution for some matrix-filler systems are compared with related experimental data from literature and some investigated systems in this work. An excellent agreement even better than prediction of Anderson's model between experimental data and model predictions can be observed in most cases especially for some concentrated systems. POLYM. COMPOS., 31:1150,1155, 2010. © 2009 Society of Plastics Engineers [source]

An investigation on the mechanical and dynamic rheological properties of single and hybrid filler/polypropylene composites based on talc and calcium carbonate

POLYMER COMPOSITES, Issue 12 2009
Hamed Azizi
Some results of experiments on the mechanical and rheological properties of mineral filled polypropylene were presented. Single filler and hybrid filler composites of talc and calcium carbonate (CaCO3) were prepared in a co-rotating twin-screw extruder. The effect of filler type, filler content, and coupling agent on the mechanical and rheological properties of the polypropylene were studied. The coupling agent was maleic anhydride-grafted polypropylene (PP- g -MA). It was found that the mechanical properties are affected by filler type, filler concentration, and the interaction between filler and matrix. The tensile strength of the composite is more affected by the talc while the impact strength is influenced mostly by CaCO3 content. The elongation at break of PP/CaCO3 composites was higher than that of PP/talc composites. The incorporation of coupling agent into PP/mineral filler composites increased the mechanical properties. Rheological properties indicated that the complex viscosity and storage modulus of talc filled samples were higher than those of calcium carbonate filled samples while the tan , was lower. The rheological properties of hybrid-filler filled sample were more affected by the talc than calcium carbonate. The PP- g -MA increased the complex viscosity and storage modulus of both single and hybrid composites. POLYM. COMPOS., 2009. © 2009 Society of Plastics Engineers [source]

Thermomechanical studies of aluminum nitride filled shape memory polymer composites

POLYMER COMPOSITES, Issue 3 2007
Muhammad Yasar Razzaq
High thermal conductivity polyurethane shape memory polymer (SMP) composites filled with aluminum nitride (AlN) were fabricated, and their thermal and thermomechanical properties were studied. The purpose of this microstructure is to improve the thermal properties of the SMPs at low filler content. Morphology of AlN filler in polyurethane SMP matrix and the resulting thermal conductivity was also investigated. Thermal studies have shown that AlN is an effective filler for reinforcement of the polyurethane SMP and that it does not deteriorate the stable physical crosslink structure of the polyurethane, which is necessary to store the elastic energy in the service process of the shape memory material. The thermal conductivities of these SMP composites in relation to filler concentration and temperature were investigated, and it was found that the thermal conductivity can increase up to 50 times in comparison with that of the pure SMP. Furthermore, differential scanning calorimetry tests have shown a significant decrease in the glass transition temperature of the switching segment. Dynamic mechanical studies have shown that the storage modulus of the composites increase with higher AlN content in both glassy and rubbery state. Damping peak decreases and also the curve of damping becomes broader with increasing filler content. Strain fixity rate which expresses the ability of the specimens to fix their strain has been improved slightly in the presence of AlN filler but the final recovery rate of the shape memory measurement has decreased evidently. POLYM. COMPOS., 28:287,293, 2007. © 2007 Society of Plastics Engineers [source]

Molecular transport of aromatic hydrocarbons through lignin-filled natural rubber composites

POLYMER COMPOSITES, Issue 1 2007
Thomas V. Mathew
The diffusion and transport of organic solvents through lignin-filled natural rubber composites have been studied in the temperature range 25,45°C. The diffusion of aromatic solvents through these samples were studied with special reference to the effect of filler concentration, penetrant size, and temperature. Transport coefficients such as diffusion, permeation, and sorption coefficients were estimated. The van't Hoff relationship was used to determine the thermodynamic parameters. The first order kinetic rate constant has been evaluated. A correlation between theoretical and experimental sorption results was evaluated. POLYM. COMPOS., 28:15,22, 2007. © 2007 Society of Plastics Engineers [source]

Extension rheology of liquid-crystalline solution/layered silicate hybrids

POLYMER ENGINEERING & SCIENCE, Issue 4 2010
Gleb B. Vasilyev
The extension rheology of polymer/layered silicate composites based on liquid-crystalline (LC) solution of hydroxypropylcellulose (HPC) in oligomeric polyethyleneglycole (PEG) was studied. The HPC concentration was 60 wt%. Extension experiments have been carried out for materials in the different phase states. Compositions containing Na-montmorillonite (MMT) were prepared by a two-stage method. Final systems may be attributed to solutions of HPC in PEG, which intercalates into MMT galleries. The ordered domain structure of the LC matrix as well as hydrogen-bonded network between HPC and PEG molecules significantly reduce deformation at break and provide a strong nonlinear viscoelastic behavior at extension. Appearance of isotropic phase in solutions leads to a sharp drop of the elongation viscosity. The introduction of clay into LC solution only slightly affects the viscosity value but significantly suppresses the strain-hardening scale. In contrast, loading in biphasic state of HPC-PEG solution with even small amount (1 wt%) of MMT leads to the drastic viscosity increase that does not change in further growth of the filler concentration. Elastic properties of the systems under study demonstrate the similar behavior. This effect likely is caused by the interrelationship between deformability of the LC domain structure and the network strength formed by the clay particles. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers [source]

AC impedance analysis and EMI shielding effectiveness of conductive SBR composites

POLYMER ENGINEERING & SCIENCE, Issue 10 2006
G.T. Mohanraj
Flexible conductive polymer composites were prepared using styrene,butadiene rubber (SBR) as a matrix and conductive carbon black as filler. The filler loading was varied from 10 to 60 phr. The complex AC impedance and electromagnetic interference shielding effectiveness (EMI SE) of the composites were measured at the microwave frequencies of 7.8,12.4 GHz. The effect of variation in filler concentration and measurement frequency on the AC impedance and EMI SE of the composites were investigated. Equivalent circuits describing the conduction behavior of the composites were determined by means of Nyquist plots. The complex electric modulus of the composites was also determined. Increase in the filler loading increased the capacitive nature of the materials. The composites were better defined by a parallel resistor,capacitor circuit in series with a resistor. The EMI SE was found to pass through a maximum with increase in frequency. However, with the increase in filler loading and sample thickness of the material, the EMI SE was found to increase continuously. POLYM. ENG. SCI., 46:1342,1349, 2006. © 2006 Society of Plastics Engineers. [source]

Application of ultrasound and neural networks in the determination of filler dispersion during polymer extrusion processes

POLYMER ENGINEERING & SCIENCE, Issue 6 2005
Zhigang Sun
Mineral filler dispersion is important information for the production of mineral-charged polymers. In order to achieve timely control of product quality, a technique capable of providing real-time information on filler dispersion is highly desirable. In this work, ultrasound, temperature, and pressure sensors as well as an amperemeter of the extruder motor drive were used to monitor the extrusion of mineral-filled polymers under various experimental conditions in terms of filler type, filler concentration, feeding rate, screw rotation speed, and barrel temperature. Then, neural network relationships were established among the filler dispersion index and three categories of variables, namely, control variables of the extruder, extruder-dependent measured variables, and extruder-independent measured variables (based on ultrasonic measurement). Of the three categories of variables, the process control variables and extruder-independent ultrasonically measured variables performed best in inferring the dispersion index through a neural network model. While the neural network model based on control variables could help determine the optimal experimental conditions to achieve a dispersion index, the extruder-independent network model based on ultrasonic measurement is suitable for in-line measurement of the quality of dispersion. This study has demonstrated the feasibility of using ultrasound and neural networks for in-line monitoring of dispersion during extrusion processes of mineral-charged polymers. POLYM. ENG. SCI., 45:764,772, 2005. © 2005 Society of Plastics Engineers [source]

Molecular orientation, crystallinity, and flexural modulus correlations in injection molded polypropylene/talc composites

POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 5 2010
Marcia Cristina Branciforti
Abstract In order to promote better understanding of the structure-mechanical properties relationships of filled thermoplastic compounds, the molecular orientation and the degree of crystallinity of injection molded talc-filled isotactic polypropylene (PP) composites were investigated by X-ray pole figures and wide-angle X-ray diffraction (WAXD). The usual orientation of the filler particles, where the plate planes of talc particles are oriented parallel to the surface of injection molding and influence the orientation of the , -PP crystallites was observed. The PP crystallites show bimodal orientation in which the c - and a*-axes are mixed oriented to the longitudinal direction (LD) and the b -axis is oriented to the normal direction (ND). It was found that the preferential b -axis orientation of PP crystallites increases significantly in the presence of talc particles up to 20,wt% in the composites and then levels-off at higher filler content. WAXD measurements of the degree of crystallinity through the thickness of injection molded PP/talc composites indicated an increasing gradient of PP matrix crystallinity content from the core to the skin layers of the molded plaques. Also, the bulk PP crystallinity content of the composites, as determined by DSC measurements, increased with talc filler concentration. The bulk crystallinity content of PP matrix and the orientation behavior of the matrix PP crystallites and that of the talc particles in composites are influenced by the presence of the filler content and these three composite's microstructure modification factors influence significantly the flexural moduli and the mechanical stiffness anisotropy data (ELD/ETD) of the analyzed PP/talc composites. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Gel point prediction of metal-filled castor oil-based polyurethanes system,

POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 10-12 2002
Anil Srivastava
Abstract Prediction of gel point conversion and network formation is of great importance in polycondensation during synthesis as well as processing. It enables one to estimate the safe conversions for reactor operation without gelation and the cycle time during processing, and plays an important role in controlling the molding parameters used for reinforced reaction injection molding (RRIM), reaction injection molding (RIM) and compression molding. Theories of gelation have been extensively published in the literature and supported by experimental data for various polycondensation systems. However, most such studies relate to unfilled systems. In this work, metal-filled polyurethanes have been synthesized in bulk by reacting toluene di-isocyanate with castor oil and its polyols possessing different hydroxyl values. Metallic aluminum powder (10,40% by weight) was dispersed thoroughly in castor oil and its polyols before reacting at different temperatures (30,60,°C) in a moisture-free, inert environment. The gel point conversions were measured experimentally and an empirical model from the experimental data has been developed to predict the gelation behavior. The proposed model could be of immense importance in the paints, adhesives and lacquers industries, which use castor oil in bulk. From these experiments it was concluded that: (i) fine metal powder gives a rise in viscosity; (ii) metal fillers not only restrict the molecular motion due to the increase in viscosity, but also lower the conversion; (iii) the vegetable oil and its polyols have a number of bulky groups, which also impart the delay tendency in gel time; (iv) there is a change in gelation dynamics at 50,°C , this is due to the change in reactivity of di-isocyanates; (v) the presence of metal filler does not initiate the intermolecular condensation; (vi) there is a gap between theoretical and experimental gel point owing to the unequal reactivity of the secondary alcohol position; (vii) there is an inverse relationship of gel time with the reaction temperature and hydroxyl value of polyols. An empirical model based on process parameters, i.e., hydroxyl value, temperature, shape factor and filler concentration, has been derived and found to be adequate for the metal-filled system. The correlation coefficient on the data is on the lower side in some cases because the following were not taken into account: (i) the first-order kinetics followed by the reaction in the second half while it is tending towards gelation; (ii) the error in observing the gel point viscosity; (iii) errors in assuming the spherical shape of aluminum metal powder; (iv) errors due to failure to maintain the constant speed in agitation. Copyright © 2003 John Wiley & Sons, Ltd. [source]