Effect Of Filler Size Research Articles

Filler Size Effects on Reinforcement in Elastomer-Based Nanocomposites: Experimental and Simulational Insights into Physical Mechanisms

Nanocomposites consisting of polymers reinforced with filler particles are important for a wide variety of industries and processes, but although they exhibit unique viscoelastic properties and as such are widely applied in e.g. tires, the precise mechanism of their reinforcement is at best incompletely understood at present. In order to understand it at a fundamental level, and ultimately control it in practice, it is essential to determine the impact of interactions between filler particles and polymer matrix on the nanocomposite microstructure and its macroscopic dynamic mechanical properties. To this end, we performed experiments on two model systems as well as molecular dynamics simulations, aiming to determine to what extent widely used shear-distortion models of the reinforcement are applicable as well as the role played by molecular interactions on the enhancement of the mechanical properties. In both experiments and simulations a linear dependence of the reinforcement on the inverse radius of the...

Effect of Various Fillers on Mechanical Properties of Glass Fiber Reinforced Polymer Composites: A Review

Filler materials are the inert materials which are used in glass fiber reinforced polymer (GFRP) composites for modifying the chemical and physical properties of the matrix polymers to reduce material costs, to improve processability, to improve product performance or to simply act as extenders or matrix diluents. Some of the commonly used fillers are carbon black, calcium carbonate, clay, alumina tri-hydrate, magnesium hydroxide, bone powder, coconut powder, hematite powder, TiO2, SiO2,ZnS, graphite, etc. Effect of these fillers on mechanical properties like tensile strength, flexural strength, inter laminar shear strength (ILSS), tensile modulus, impact strength, hardness were tested by various methods experimentally. Some of the authors also discussed the effect of filler size on the above mechanical properties. KeywordsFillers, glass fiber reinforced polymer composites (GFRP), Mechanical properties Introduction Filler materials are generally the inert materials which are used in composite materials to reduce material costs, to improve mechanical properties to some extent, in some cases to improve processability and to improve product performance. Two or more materials with different material properties are combined together they will form a composite material. Fibers when embedded with weaker matrix materials comprise of strong load carrying capacity.The fibers in the composite materials will improve the mechanical properties such as tensile strength, flexural strength, impact strength, stiffness and matrix will transfer stresses between the reinforcing fibers. Fiber reinforced polymer composites are also called as fibrous composites because they consists of fibers as the reinforcing materials. The applications of composite materials are in automotive, marine, aerospace, etc. because of having properties such as high specific strength and stiffness. The types of composite materials are metal matrix composites, ceramic matrix composites and polymer matrix composites. When the matrix material is taken as ceramic it is called as ceramic matrix composite. The properties of ceramic matrix composites are better toughness, high strength, hardness, high temperature properties and better wear resistance.When the polymer resin is used as a matrix material then it is called as polymer matrix composite. These materials are having properties such as low density, good thermal and electrical insulator, ease of fabrication and low cost. The properties of polymer matrix composites mainly depend upon types of reinforcement that is particles and fibers, the type of polymer used and interface which is used between them. Polymers are classified into thermoplastics and thermosets. Thermoplastic materials are reversible and reshaped by

Antimicrobial polymer composites with copper micro- and nanoparticles: Effect of particle size and polymer matrix

The addition of metal particles, for instance, silver or copper, into polymer matrices is a relevant strategy producing novel antimicrobial materials. By using two particles with diameters around 10 nm and 45 µm, and polymers with different characteristics, the effect of filler size and matrix on the biocide behavior of polymer/copper composites was studied. The composites were prepared by melt mixing, and the ion release from these materials was used to obtain critical information about the processes involved. Regarding the effect of the particle size, our results for polypropylene showed that this variable drastically changes the release of copper from the matrix. The ion release rate from nanocomposites increased quickly exhibiting a sharp maximum during the first day; meanwhile, in microcomposites, the release rate increased slowly releasing lower ions. The relevance of particle size was confirmed by the antibacterial behavior of the samples as polypropylene with nanoparticles displayed larger activities against Staphylococcus aureus and Pseudomonas aeruginosa bacteria than microcomposites. These results further showed the relationship between copper ion release and antimicrobial behavior in polymer/metal composites. Our findings further revealed that the ion release from polymer composites could be improved by either increasing the hydrophilic characteristic of the matrix or by lowering its crystallinity. These observations allowed the conclusion that both the polymeric matrix and the size of the metal filler are relevant variables toward the design of antimicrobial composite materials.

Study of optimal filler size for high performance polymer-filler composite optical reflectors

Polymer-based diffuse reflectors are cost-effective and high performance alternatives to metallic reflectors and multilayered dielectric mirrors in optical and photonic modules. In this study, we optimized the reflectance of high performance polymer-based reflectors by controlling filler particle size. We use a simple analytical model to investigate the critical size of inorganic fillers required to obtain the highest reflectance with a lower filler volume fraction and reflector thickness. The key model predictions show good agreement with our experimental data using Al2O3-silicone and TiO2-silicone composite reflectors. Our results demonstrate for the first time that for inorganic fillers, the effect of filler size on reflectance is non-monotonic, and a critical filler size ranging from one submicron to several microns provides the maximum reflectance. We observed a 50% difference in optical reflectance between 1 micron and 35 micron Al2O3 at 0.1 volume fraction. A significant improvement in reflectance for polymer-filler reflectors can be realized by utilizing optimized filler size, in order to increase the performance-price ratio for optical and photonic devices.

Thermal conductivity of calcium carbonate filled with unsaturated polyester composites with different filler sizes

The effect of filler size to the thermal conductivity of the calcium carbonatefilled with unsaturated polyester composites has been experimentally investigated. The filler was derived from the shell of local clam known as Polymesoda bengalensis. Neat unsaturated polyester samples and calcium carbonate filler with eight different mean diameter sizes were embedded in the unsaturated polyester with 8 wt-% filler loading. Thermal conductivity was measured by applying the guarded heat flow meter method according to ASTM E1225-99 using P.A Hilton Heat Conduction Unit H-940. The result shows that at constant filler content, the thermal conductivity of calcium carbonate/unsaturated polyester composites were increased gradually as the filler size was decreased.

Filler networking in the highly nanofilled systems

Filler networking is considered as the most important parameter in controlling the mechanical and rheological properties of highly filled systems. Besides, the interparticle distance as a function of filler size and concentration seems to be the main parameter to govern the filler network strength or filler–filler interaction. In this article, considering the importance of filler networking, estimation of the interparticle distance for different values of filler size and concentration, investigation of the architecture of filler network in the nanocomposite for various filler sizes as well as analysis of the effects of filler size and concentration on the dynamic behavior of the filler networks are discussed and atomic force microscopic imaging is used to investigate the filler network parameters. In addition to the proposed filler network structure, the results suggest that the rheological properties of nanocomposites in the linear region could be related to the interparticle distance independent of filler size and concentration. On the other hand, by studying the linear and nonlinear viscoelastic properties of these highly filled systems, the results indicate that an increase in loss and storage modulus would occur by increasing the filler concentration and reducing the filler size.

A systematic study on electrical properties of the BaTiO3–epoxy composite with different sized BaTiO3 as fillers

The epoxy composites consisting of BaTiO3 fillers with size of 100nm and 200nm were prepared, respectively. The thermo-mechanical and electrical properties of BaTiO3–epoxy composites were investigated using complex permittivity, electric modulus and ac electrical conductivity. The effects of filler size on the structure, filler–matrix interface and properties were discussed. The Havriliak–Negami model was used to analyze the dielectric relaxation of composites. The results show that larger filler tends to exhibit enhanced dynamic modulus and higher Tg because of the increase of effective volume fraction. The tetragonal phase formation in the BaTiO3 is important to achieve enhanced permittivity of the composite. The relaxation responses of composites revealed by electric modulus and complex permittivity show that the Maxwell–Wagner–Sillars (MWS) polarization and tetragonal phase transition of BaTiO3 affect the dielectric responses of composites. The conduction process is not only related with the barrier hopping but also tunneling effect of electrons. Based on the electrical properties of BaTiO3–epoxy composite with 100nm BaTiO3 at GHz, a compact band-pass filter with significant area reduction was designed and fabricated. The measured results show that the BaTiO3–epoxy composite is promising for advanced wireless device applications.

Mechanical and thermal investigation of thermoplastic nanocomposite films fabricated using micro- and nano-sized fillers from recycled cotton T-shirts

The thermal and mechanical performance of composites with nano-sized cotton fillers embedded in low-density polyethylene (LDPE) is investigated. Microfibrillated cotton was prepared by microgrinding mechanical treatment of pulverized cotton (pCot) derived from waste T-shirts, resulting in nano-sized fibrils of the cellulose that retain high crystallinity. Film composites of LDPE with pCot before and after microgrinding were fabricated through melt extrusion and the effect of filler size on mechanical, thermal and morphological properties of the composite was investigated. Compounding microfibrillated cotton with LDPE resulted in well-dispersed nanocomposites with no discoloration after 10 min of melt extrusion at 170 °C. At concentrations up to 10 % by weight, the composites showed increased modulus, increased tensile strength and a slight decrease in elongation to break. Further improvement in the dispersion and mechanical properties of the cotton-based fillers was realized by the use of LDPE powder instead of polymer pellets fed to the extruder. This research demonstrates the processing and applicability of the use of recycled cotton-based nano-sized fillers in melt-processing.

A low-cost filler-dissolved process for fabricating super-hydrophobic poly(dimethylsiloxane) surfaces with either lotus or petal effect

A low-cost filler (salt) water-dissolved method is developed to produce large-area and flexible super-hydrophobic surfaces by using poly(dimethylsiloxane) (PDMS) material. Five levels of salt grain sizes are used to examine the filler size effect on fabricating the super-hydrophobic surfaces and on the hydrophobic mechanism involved. The results show that the surfaces fabricated using grain sizes of 53–74 and 74–104 µm exhibit the lotus effect (cell adhesion (CA) > 150° and self-adhesion (SA) < 10°); whereas those using grain sizes of 0–25 µm and above 104 µm reveal the petal effect (CA > 150° and high adhesion even upside-down). The super-hydrophobic characteristic is achieved mainly by the large micro rib-like structures, small micro rock-like bumps, and textures on the bump due to the fillers.

Evaluation of dielectric models for ceramic/polymer composites: Effect of filler size and concentration

The main theoretical models for evaluation of the dielectric constant of ceramic/polymer composites are summarized and applied to PZT/poly(vinylidene fluoride) and BaTiO3/poly(vinylidene fluoride) composites with varying filler concentration and size in order to evaluate the suitability of the models and the main interactions that are responsible for the composite dielectric behavior.All models predict an increase in dielectric constant with increasing filler content. On the other hand, this increase is different for different models, showing the relative importance of the different interactions. Experimentally, the size of the inclusions plays an important role in determining the dielectric behavior of a composite, especially at the nanoscale. Effects occurring at the interface between the filler particles and the matrix become important as the relative surface area at the interface increases. Models not including fitting parameters do not properly represent the increase in dielectric constant with increasing filler content and none of them seem to properly represent the dielectric behavior of nanocomposites. In this way, the effects contemplated by the models – interactions between the particles, interactions with the field, depolarization factor or shape parameter – are not sufficient to account for the variations of the dielectric behavior related to the sizes of the particles.

Effect of Filler Size on Flexural Properties of Calcium Carbonate Derived from Clam Shell Filled with Unsaturated Polyester Composites

The effect of filler size to the flexural properties of the calcium carbonate (CaCO3) filled with unsaturated polyester (UP) composites have been experimentally investigated. The filler was derived from the shell of local clam known asPolymesoda bengalensis. The ground shells were graded into eight different sizes according to the sieve aperture size of which they could pass through. The sample with 4 wt% CaCO3reinforced with UP was fabricated. Then, the flexural test was done according to the ASTM D790. The result shows that for micron size filler, the flexural modulus was improved as the powder was filled into the UP matrix composite and the maximum value achieved at 574.81 μm mean diameter filler size. However, the infusion of the micron size CaCO3filler into the UP matrix decreases the flexural strength of the composites.

Effect of Filler Size on the Thermal Properties of ER/BaTiO3 Composites

SummaryEpoxy resin/barium titanate nano‐ and micro‐composites were prepared and studied, varying the filler content. Thermal properties of the composite systems were examined by means of Thermogravimetric/Differential Thermal Analysis, while dielectric response was assessed via Dielectric Relaxation Spectroscopy. Decomposition temperature found not to vary with filler size, while thermal stability of reinforced systems is enhanced compared to epoxy resin. Nanocomposites exhibit, improved thermal properties compared to micro‐composites at the same filler content. Composite systems attain higher values of dielectric permittivity, and relaxation processes are present in all studied systems.

Effect of filler size on thermophysical and electrical behavior of nanocomposites based on expanded graphite nanoparticles filled in low‐density polyethylene matrix

AbstractVarious aspects of electrical and thermophysical properties of nanocomposites based on low‐density polyethylene matrix filled with nanostructuralized expanded graphite (EG) and standard, microsized graphite are presented in this article. A periodical method developed in the laboratory was used to measure simultaneously thermal conductivity, specific heat, and diffusivity of composites at room temperature. The effect of micro‐ and nanosized fillers on the final thermophysical and electrical behavior is investigated. It was found that the electrical conductivity of composites strongly depends not only on the filler content but also on the filler size. When the microsized graphite was used, the percolation concentration of the filler was found to be 15 vol%, whereas the percolation concentration of the filler in nanocomposites filled with EG of large sizes was significantly lower. Similarly, it was shown that the graphite significantly improves the thermophysical behavior of composites filled with micro‐ and nanofiller sizes. The thermal conductivity measured values were also compared with some theoretical models for the prediction of the thermal conductivity. POLYM. COMPOS., 2012. © 2013 Society of Plastics Engineers

Elastic Stiffness and Filler Size Effect of Covalently Grafted Nanosilica Polyimide Composites: Molecular Dynamics Study

The filler size-dependent elastic stiffness of nanosilica (α-quartz)-reinforced polyimide(s-BPDA/1,3,4-APB) composites under the same volume fraction and grafting ratio conditions was investigated via molecular dynamics(MD) simulations. To enhance the interfacial load transfer efficiency, we treated the surface oxygen atoms of the silica nanoparticle with additional silicon atoms attached by a propyl group to which the aromatic hydrocarbon in the polyimide is directly grafted. As the radius of the embedded nanoparticle increases, the Young's and shear moduli gradually decrease, showing a prominent filler size effect. At the same time, the moduli of the nanocomposites increase as the grafting ratio increases. The contribution of different nanoparticles to the filler size dependency in elastic stiffness of the nanocomposites can be elucidated by comparing the normalized adhesive interaction energy between the particle and matrix which exhibits prominent filler size dependency. Because of the immobilization of the matrix polymer in the vicinity of the nanoparticles, which was confirmed by the self-diffusion coefficient, the highly grafted interface is found to bring about a greater reinforcing effect than the ungrafted interface.

Effects of Filler Size and Distribution on Viscous Behavior of Glass Composites

We study the viscous behavior of glass composites with respect to type of filler, filler size, distribution, and interaction between the matrix and filler for industrial applications. Here, the viscosities of the composites were analyzed as a function of the type/size of the fillers (up to 20 wt% of Al2O3, ZnO, and TiO2) in a glass (Bi2O3–B2O3–ZnO) matrix. The particle size was varied from 1 to 10 μm, which influenced the fluidity of the glass matrix in the composite. Characterizations of the composites were carried out by dilatometry, differential thermal analysis, hot‐stage microscopy, and scanning electron microscopy. Fillers having the same particle size as that of the parent glass showed better fluidity behavior. With higher filler content, the filler plays no role in the composite's behavior, whereas a lower to medium amount of filler plays a significant role in the composite's behavior. Fillers with smaller sizes than those of the glass matrix show good dispersion throughout the matrix but agglomeration was observed in some areas.

Effect of filler size and morphology on viscoelastic stability of resin-composites under dynamic loading

Effect of variation in filler particle size, morphology and wet conditioning on the viscoelastic stability of resin-composites under dynamic loading was investigated. Eight experimental light cured resin-composites were selected. For each of the eight resin-composites, ten cylindrical specimens (4 × 6 mm), divided into two subgroups (n = 5) were prepared. Group 1 and 2 were loaded dynamically after 1 day of dry storage and 1 week of wet storage, respectively. A cyclic load between 1 and 50 MPa was applied for both groups at a frequency of 0.25 Hz for 30 min to obtain the 'dynamic' creep strain (%). Data was analysed by univariate ANOVA. Unimodal spherical and irregular resin-composites showed a significant influence of particle size and shape on dynamic creep under dry condition, but not for wet conditions. Irregular filler particles in both unimodal and multimodal resin-composites were more resistant to dynamic creep under wet conditions and showed higher stiffness.

Effect of filler size and concentration on the structure and properties of poly(vinylidene fluoride)/BaTiO3 nanocomposites

The effect of filler size and content in the thermal, mechanical, and electrical response of poly(vinylidene fluoride) (PVDF)/BaTiO3 nanocomposites has been investigated. Dielectric constant increases significantly with increasing filler content and decreasing filler size. Space charge effects at the interface between BaTiO3 and PVDF strongly influence the dielectric response. The electroactive β-phase of PVDF is nucleated by the presence of the ceramic filler, the effect being strongly dependent on filler size and independent on filler content. This filler/matrix interaction is also responsible for the variations observed in the activation energy of the thermal degradation of the polymer. Smaller particles lead to larger relative contact areas and are responsible for the main variations observed in the thermal, mechanical, and electrical properties of the composites.

Effect of Filler Size and Temperature on Packing Stress and Viscosity of Resin-composites

The objective of this study was to investigate the effect of filler size on the packing stress and viscosity of uncured resin-composite at 23 °C and 37 °C. A precision instrument used was designed upon the penetrometer principle. Eight resin-composite materials were tested. Packing-stress ranged from 2.60 to 0.43 MPa and viscosity ranged from 2.88 to 0.02 MPa.s at 23 °C. Values for both properties were reduced significantly at 37 °C. Statistical analysis, by ANOVA and post hoc methods, were carried out to check any significant differences between materials tested (P < 0.05). Conclusions: Filler size and distribution will affect the viscosity and packing of resin-composites during cavity placement.

OS0903 フィラーハイブリッド型歯科用コンポジットレジンの疲労強度向上法の検討(OS9-1 生体機能・材料(金属材料),OS-9 生体機能・材料)

Dental resin composites have been widely used in clinical, because of its operability and sensuousness. Since the resin composite is subject to cyclic stress in the oral environment, an understanding of the fatigue strength of these materials is needed to use with keeping safety. In this study, three-point bending fatigue tests of resin composites with several filler blend ratios were conducted to investigate the effect of filler size and filler content on fatigue strength. In order to consider an environmental property of the resin composite, the fatigue strength was also investigated in ethanol solution.

THE EFFECT OF MIXED FILLER SIZES ON THE FIBER DIAMETER OF ELECTROSPUN BUTYL RUBBER FORMULATIONS

Abstract Electrospinning of thermosetting elastomers is a method for developing nonwoven membranes with a microporous structure for use in dynamic applications (i.e., stretchable). These membranes have potential for chemical protective clothing applications. The most challenging concerns are the ability to control pore sizes, fiber diameter, permeability, and physical properties. We investigated the effect on fiber diameters as a ratio of two different carbon black particulate sizes. Carbon black N110 and N990 were incorporated at various percentages of total carbon black loading in a butyl rubber formulation. Higher levels of small particulates were found to give smaller and more consistent fiber diameters. Understanding of the effects of filler size and concentration on the electrospinning process will lead to the successful tailoring of nonwoven membranes with desired fiber diameter and pore size.