Effect Of Inorganic Fillers Research Articles

Effect of Inorganic Fillers on Electrical and Mechanical Properties of Ceramizable Silicone Rubber.

Ceramizable silicone rubber (CSR) composed of silicone rubber matrix and inorganic fillers can be transformed into a dense flame-retardant ceramic upon encountering high temperatures or flames. Conventionally, CSR can be sintered into a dense ceramic at temperatures above 1000 °C, which is higher than the melting point of a copper conductor used in a power cable. In this study, the vulcanization process and mass ratio of inorganic fillers of CSR were studied to lower its ceramization temperature to 950 °C. The electrical and mechanical properties of CSRs and their ceramic bulks were studied with various ratios of wollastonite and muscovite. It was found that the CSR samples could be successfully fabricated using a two-step vulcanization technique (at 120 °C and 150 °C, respectively). As a high ratio of muscovite filler was introduced into the CSR, the sample presented a high dc electrical resistivity of 6.713 × 1014 Ω·cm, and a low dielectric constant of 4.3 and dielectric loss of 0.025 at 50 Hz. After the thermal sintering (at 950 °C for 1 h) of the CSR sample with a high ratio of muscovite, the ceramic sample exhibits a dense microstructure without any pores. The ceramic also demonstrates excellent insulating properties, with a volume resistivity of 8.69 × 1011 Ω·cm, and a low dielectric loss of 0.01 at 50 Hz. Meanwhile, the three-point bending strength of the ceramic sample reaches a value of 110.03 MPa. This study provides a potential route to fabricate CSR used for fire-resistant cables.

Effect of inorganic fillers on the light transmission through traditional or flowable resin-matrix composites for restorative dentistry

ObjectivesThe aim of this in vitro study was to evaluate the light transmission through five different resin-matrix composites regarding the inorganic filler content.MethodsResin-matrix composite disc-shaped specimens were prepared on glass molds. Three traditional resin-matrix composites contained inorganic fillers at 74, 80, and 89 wt. % while two flowable composites revealed 60 and 62.5 wt. % inorganic fillers. Light transmission through the resin-matrix composites was assessed using a spectrophotometer with an integrated monochromator before and after light curing for 10, 20, or 40s. Elastic modulus and nanohardness were evaluated through nanoindentation’s tests, while Vicker’s hardness was measured by micro-hardness assessment. Chemical analyses were performed by FTIR and EDS, while microstructural analysis was conducted by optical microscopy and scanning electron microscopy. Data were evaluated using two-way ANOVA and Tukey’s test (p < 0.05).ResultsAfter polymerization, optical transmittance increased for all specimens above 650-nm wavelength irradiation since higher light exposure time leads to increased light transmittance. At 20- or 40-s irradiation, similar light transmittance was recorded for resin composites with 60, 62, 74, or 78–80 wt. % inorganic fillers. The lowest light transmittance was recorded for a resin-matrix composite reinforced with 89 wt. % inorganic fillers. Thus, the size of inorganic fillers ranged from nano- up to micro-scale dimensions and the high content of micro-scale inorganic particles can change the light pathway and decrease the light transmittance through the materials. At 850-nm wavelength, the average ratio between polymerized and non-polymerized specimens increased by 1.6 times for the resin composite with 89 wt. % fillers, while the composites with 60 wt. % fillers revealed an increased ratio by 3.5 times higher than that recorded at 600-nm wavelength. High mean values of elastic modulus, nano-hardness, and micro-hardness were recorded for the resin-matrix composites with the highest inorganic content.ConclusionsA high content of inorganic fillers at 89 wt.% decreased the light transmission through resin-matrix composites. However, certain types of fillers do not interfere on the light transmission, maintaining an optimal polymerization and the physical properties of the resin-matrix composites.Clinical significanceThe type and content of inorganic fillers in the chemical composition of resin-matrix composites do affect their polymerization mode. As a consequence, the clinical performance of resin-matrix composites can be compromised, leading to variable physical properties and degradation.Graphical

Assessment of the effect on the plasticizer diffusion of inorganic fillers in plasticized poly(vinyl chloride) composite films for cable sheath applications

AbstractIn cable sheath applications, plasticizer migration is important as it causes reduction in mechanical properties, deterioration, and pollution in transported environments. This study focuses on the effect of inorganic fillers on the diffusion of plasticizers from plasticized‐PVC cable films. Plastisols were prepared by mixing plasticizer, thermal stabilizers, and inorganic fillers (boric acid, boron clay, sintered calcined boron waste clay, talc, and zircon oxide) into the PVC resin. Plastigel films were cured and thermally aged at 100, 130, and 160°C. Oxidation index were determined by Fourier transform infrared spectroscopy. The diffusion coefficient and activation energies were calculated from mass loss. Thermogravimetric analysis analyses were performed to obtain weight loss. Fillers were characterized for their zeta potential, particle size distribution, polydispersion. Morphology of the fillers was also conducted using scanning electron microscopy. Their mechanical and rheological analyses were evaluated with the tensile and melt flow index test. The order of diffusivity was determined as the films having boric acid &gt; undoped &gt; talc = sintered boron clay &gt; zircon &gt; boron clay. The result of this evaluations is the addition of inorganic filler increases the mechanical and thermal applicability and reduces the plasticizer diffusion. It is thought that the results, will contribute to the studies on the plasticizer transition in cable applications.

Effect of ZIF-7 doping content on H2/CO2 separation performance of 1,2-bis(triethoxysilyl)ethane-derived organosilica membranes

Organosilica membranes with good hydrothermal stability are promising for pre-combustion capture, but the trade-off effect still constrains their gas separation performance. Herein, we prepared hybrid membranes by incorporating ZIF-7 nanoparticles into 1, 2-bis(triethoxysilyl)ethane (BTESE) networks to improve the H2/CO2 permselectivity by the intrinsic properties of nanoparticles. The effect of inorganic fillers was investigated by adjusting the doping content of ZIF-7 nanoparticles. We found that the H2 permeance of hybrid membranes remained at ∼10−6 mol·m−2·s−1·Pa−1, while the H2/CO2 permselectivity decreased with increasing nanoparticle doping content. The E-ZIF-7-0.4 hybrid membrane showed H2 permeance of 1.2 × 10−6 mol·m−2·s−1·Pa−1 and H2/CO2 permselectivity of 21.7. Our results may offer valuable insights into preparing hybrid membranes with optimal nanoparticle doping content.

Development of Hybrid Titania/Polybenzoxazine Composite for Enhance Thermomechanical, Flame Retardancy and Dielectric Properties

Polybenzoxazines (Pbzs) are a recently developed class of thermosetting polymeric materials possessing low surface free energy with nonfluorine or nonsilicon content. In the present study, a new type of Pbz-BN/TiO2 composite was fabricated using benzoxazine monomer bis(6-phenyl diazenyl-3-phenoxy-3,4-dihydro-2H-1,3-benzoxazinyl) benzonitrile and inorganic TiO2 fillers by a simple and inexpensive process. The thermal curing method was found to be effective for preparing superhydrophobic surfaces combining low surface energy and surface roughness. The presence of the benzonitrile group in the benzoxazine monomer paves the way for accelerating the curing of the benzoxazine monomer, as shown by the DSC analysis. The as-prepared Pbz/TiO2 surfaces containing 5 wt% of TiO2 generated a superhydrophobic surface exhibiting a static water contact angle (SWCA) of 146°. In addition, the effect of inorganic fillers on the thermal, mechanical and dielectric properties of the Pbz/TiO2 composites was investigated in detail.

Characterization of the Effect of Hollow Glass Beads on the Mechanical Properties of Structural Adhesives.

Adhesives are extensively used in the automotive and aeronautical industries as they enable the creation of durable and light weight joints, with exceptional strength to weight ratios. The constant search for the means of adapting the mechanical performance of adhesives to each application has led to the use of several types of fillers to change their properties. Following a study on the effect of inorganic fillers, i.e., hollow glass beads, in the failure mechanisms of single lap joint’s (SLJ), this work focuses on the response of the strength and fracture properties of structural adhesives to this filler. To this end, their tensile strength and mode I fracture properties were thoroughly analyzed by performing bulk tensile and double-cantilever beam (DCB) tests, at a quasi-static speed. The specimens were manufactured by adding different %v/v of filler to two epoxy-based crash resistant adhesives. Both adhesives have shown a negligible effect on the tensile strength, a decrease in strain at failure and critical energy release rate in mode I, as well as an increase of the Young’s modulus, for higher % in volume of hollow glass beads. These phenomena were further analyzed recurring to scanning electron microscopy, and the concept of rule of mixtures.

Effects of inorganic fillers on the performance of the water‐based intumescent fire‐retardant coating

SummaryThe purpose of this research was to evaluate the influences of filler type and its content on the performance of a water‐based intumescent fire‐retardant coating. Three fillers (vermiculite, celite, and aluminum hydroxide) were added to the intumescent paint formulation. The thermal and fire protective properties were studied with thermogravimetric analysis (TGA), torch test, electrical furnace, scanning electron microscopy (SEM), and Fourier transform infrared analysis (FTIR). The results showed that adding fillers into coatings up to 3% could improve the intumescent coating's behavior and increase its endurance against flames. Of the three fillers used, vermiculite showed a better performance in the torch test, attributed to its chemical and physical structure. Vermiculite has low thermal conductivity and is considered an appropriate filler for heat‐insulation. The final back‐plate temperatures in the torch test for the vermiculite‐containing samples were around 100°C–150°C lower than that of other samples. Moreover, vermiculite's addition improved the coating's expansion by 10% compared with the control sample's. The vermiculite sample's char layer morphology showed a uniform cell size distribution, indicating structural robustness. The coating samples successfully transformed polypropylene flammability from highly flammable to V0 level in the UL 94 vertical burning test standard. The results showed that vermiculite could improve intumescent paint's fire resistance and be used as an enhancer in intumescent coating formulations.

Curing kinetics and thixotropic properties of epoxy resin composites with different kinds of fillers

Effect of inorganic fillers, cement powder, Na-bentonite, flay ash, on curing kinetics of bisphenol-A epoxy resin and polyamide (BAE/PA) system was investigated under iso-thermal curing condition using the differential scanning calorimeter (DSC). Meanwhile, their thixotropic properties were measured using a rheometer at 25 °C. The relation between curing kinetics and thixotropic properties was discussed. It is found that when BAE/PA system is cured under 50–100 °C, the overall reaction order (m + n) decreases with increasing temperature from 2.63 to 1.83. The whole curing reaction process can be described by the Kamal model at temperatures above 90 °C. When cured below 80 °C, the curing process changed from chemical-controlled reaction into diffusion-controlled reaction at the critical curing degree (αc). αc decreases with the decrease of curing temperature. When filled by different kinds of fillers, curing kinetics at 90 °C and thixotropic properties of the systems at 25 °C were studied. It is found that compared with fly ash and cement powder, the system with Na-bentonite has the largest thixotropic hysteresis hoop area and changes into diffusion control reaction at lower curing degree. Decreasing particle size and increasing mass fraction of Na-bentonite increased the thixotropic properties of the filled system and consequently improved the overall reaction order. It means that high surface activity and thickening effect of Na-bentonite make the epoxy-amine system shows a stronger autocatalytic effect.

Correlação entre o conteúdo inorgânico e a polimerização da matriz orgânica das resinas compostas para restaurações dentárias: uma revisão narrativa

Introduction: In recent years, resin-matrix composite materials have revealed a fast technological improvement for dental applications. However, there are still some drawbacks related to the chemical composition, polymerization, and mechanical properties of resin-matrix composites with consequences in long-term clinical success. Objective: This study aimed to perform a narrative review regarding the effects of inorganic fillers on the organic matrix polymerization of resin-matrix composites. Materials and Methods: A search was performed in PubMed using relevant related key terms related to the chemical composition, properties and polymerization of resin matrix composites. Relevant studies published between 2001 and 2021 were selected. Results: The studies included in the present research provided relevant information on the chemical composition and properties of resin composites and polymerization factors, including the time, wavelength mode, and equipment. Studies have reported that silica and silicate nano-scale particles improve light transmission through resin-matrix composites and the degree of conversion of monomers in the organic matrix. Micrometric particles with a high refractive index can decrease the degree of conversion of monomers in the organic matrix. Conclusion: The polymerization of resin matrix composites is affected by light scattering due to the type of inorganic particles and the differences in refractive indexes of inorganic and organic contents.

Pervaporation separation of N, N-dimethylformamide/water using poly (vinyl alcohol) based mixed matrix membranes

Pervaporation is a separation technique relying on the concentration gradient, often expressed as partial vapor pressures, across polymeric or polymer-composite membranes. Those membranes inevitably exhibit a strong trade-off bottleneck between permeability and selectivity of target compounds, making the search for alternative materials with advanced performance characteristics highly desirable. This work aims to incorporate the advance of polymer and inorganic fillers to synthesize mixed matrix membranes. Effect of inorganic filler on properties and separation performance of Poly (vinyl alcohol) based mixed matrix membranes was investigated extensively in terms of several means of characterization methods. The results showed that the addition of inorganic fillers, NaA, SBA-15, SiO2 and SiO2-NH2 not only enhanced the separation factor but also increased the flux of water and DMF resulting in advance in total flux. This study may provide a guide to separate DMF-water solutions and will contribute to expand the high-value utilization of mixed matrix membranes in pervaporation.

Noble aluminum-pigmented metallic polymers II: Effects of inorganic filler on weld- and flow-line visibility

Aluminum flakes, inorganic filler, and Acrylonitrile–butadiene–styrene (ABS) polymer were mixed to form noble aluminum-pigmented metallic polymers. The effects of inorganic filler on weld- and flow-line visibility were investigated using field-emission scanning electron microscopy and energy-dispersive X-ray spectroscopy. The aluminum flakes were poorly oriented and not uniformly distributed at both hole and gate locations. Addition of inorganic filler improved flake orientation and distribution quality. Traditional flakes have relatively flat surfaces and high surface areas that reflect light in a highly angular manner, which results in a metallic appearance which varies with viewing angle. Comparatively, light reflected from polymers containing both aluminum flakes and specific filler pigments exhibits much less angular dependence, i.e., the flop effect of traditional aluminum pigments is minimized. The loading, size, and shape of the inorganic filler particles affected weld and flow line visibility. Adding a spherical filler with narrow particle size distribution can better stabilize the orientation of aluminum flakes in flow- and weld-line regions compared with irregularly shaped filler particles. The choice of inorganic pigment type and its optimum loading strongly affect the visibility of flow and weld lines.

The Effect of Inorganic Fillers on the Polyaniline Synthesis

The kinetics of the synthesis of polyaniline in the presence of inorganic fillers was studied. It is shown that the acid-base surface properties of the inorganic filler affect the polymerization time. The introduction of a filler in the reaction mass containing aniline leads to a decrease in the induction period of oxidative polymerization. The decrease in the induction period is due to the fact that aniline is adsorbed on the surface of the filler. This leads to the fact that polyaniline is formed as a thin layer on the surface of the carrier. With a further increase in the content of inorganic filler, the time of the induction period increases. This is due to the fact that the surface of talc has a basic character. The use of mica as an inorganic filler leads to a decrease in the induction period of polymerization in the entire range of the carrier content studied.

Application of mineral filler in surface layer of three-layer particle board and its effect on material properties as a function of filler content

ABSTRACT Addition of mineral filler in the surface layer of three-layer particle board and its influence on material properties was studied as a function of filler content. Three-layer particle board with a density of 700 kg m−3 and 0, 10, 20, and 40% weight fraction (wt-%) of calcium carbonate filler in surface layers was produced in laboratory scale using urea formaldehyde as resin. The effect of inorganic filler on elastic and strength properties, dimensional stability and formaldehyde emissions was investigated. The results demonstrated that the addition of filler in amounts up to 10 wt-% in surface layers does not significantly affect mechanical properties. Further increase in filler addition above 10 wt-% resulted in a nearly linear decrease in bending properties and increase in water uptake, however did not significantly affect dimensional stability and formaldehyde emissions.

Effects of inorganic filler on performance and cost effectiveness of a soybean‐based adhesive

ABSTRACTA modified soybean‐based adhesive with improved bonding properties and technological applicability but reduced cost was developed based on the effects of inorganic fillers on the performance of a defatted soybean meal flour (DSF) adhesive. Investigations with Fourier transform infrared spectroscopy, X‐ray diffraction measurement, thermogravimetric analysis, scanning electron microscopy, rheology tests, zeta potential analysis, and plywood evaluation demonstrated that adding inorganic fillers could improve the technological applicability of the adhesive by alleviating shear thinning and decreasing the viscosity up to 71.2%, reduce the adhesive cost up to 9.5% and result in various effects on bonding properties. Two fillers, montmorillonoid and kaolin, were suitable for plywood for exterior use owing to significantly improved water resistance up to 58.9% resulting from penetration of DSF/crosslinker chains into the interlayers of the silicates via intercalation, stable chemical bonds between the fillers and crosslinker, and excellent compatibility between the filler particles and DSF adhesive. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48892.

Utilization of inorganic mineral filler material as partial replacement for wood fiber in medium density fiberboard (MDF) and its effect on material properties

The influence of inorganic mineral filler addition on the material properties of medium density fiberboard (MDF) was investigated at varying densities. Fibreboards with 10, 20 and 30% fibers replaced by calcium carbonate weight basis (dry/dry) and with target densities of 550, 700 and 850 kgm−3, respectively, were manufactured in a laboratory scale environment. The fiberboards were prepared by adding the mineral filler in dry powder form to the wood fibers to which urea formaldehyde UF resin in liquid state had previously been added. The obtained fiber-filler furnish, with the filler distributed uniformly by sticking to the UF resin on the fibers, was then pressed into panel forms. The effect of inorganic filler on elastic and strength properties, thickness swelling, permeability, as well as formaldehyde and volatile organic compound (VOC) emissions was quantified. The results demonstrate that the addition of mineral filler to MDF up to levels of 10 wt.% only have a small effect, if at all, on the material properties. The addition of calcium carbonate, and the associated increase in pH, does not have any effect on the strength development in the cured MDF, even though the results clearly demonstrate the negative effect on the curing kinetics of urea formaldehyde (UF) resin. Likewise, thickness swelling and formaldehyde and volatile organic compounds (VOC’s) emissions are not affected by filler addition levels of up to 10 wt.%. However, exceeding this level leads to a significant decline in strength, which is believed to be caused mainly by a reduction in the number of fiber-to-fiber stress transfer points. Further, increased emissions in VOC’s are expected due to a combination of the catalytic effect of the calcium carbonate that causes a breakdown of fatty acids to VOC’s and also increased emission rates due to a higher permeability of the MDF with filler addition levels above 10 wt.%.

Effects of Inorganic Fillers on Toughening of Vinyl Ester Resins by Modified Graphene Oxide

Graphene-based nanomaterials show great potential as tougheners for thermosetting resins because they offer effective toughening of resins at an extremely low loading level with minimal change in Tg or modulus. However, commercial resin formulations sometimes contain inorganic fillers that could affect the toughening behavior of graphene-based additives. In this study, the effects of combining modified graphene oxide (mGO) with several widely used filler materials (fumed silica, kaolin clay, and calcium carbonate) on toughening of vinyl ester resins was evaluated. The relative size of additional filler particles compared to mGO particles strongly influences the toughening effects. mGO can toughen the resin if the other filler particles are much smaller and well dispersed. In contrast, the addition of mGO to filler-containing vinyl ester resin may decrease the fracture toughness if it reduces the size of the filler inclusion. Therefore, it is important to know the behavior of a filler in a resin before app...

Effect of inorganic fillers on mechanical properties of polyurethanes

Effect of inorganic fillers on mechanical properties of polyurethanes

Cooling effects of infrared radiative inorganic fillers in heat dissipation coatings at temperatures below 400 K

Heat dissipation for electronic devices has attracted extensive interest because the reliability, lifetime, and performance are seriously affected by temperature increases during the operation. The effects of inorganic fillers in heat dissipation coatings on the temperature reduction of heat sources between 310 and 400 K were investigated. Acrylic coating films with calcium fluoride, pyrolytic boron nitride, and silicon carbide particle fillers were formed on pristine aluminum plates that were then heated in a closed system. A significant temperature reduction of about 17 K was obtained at the surface of a heat source with an acrylic coating film including calcium fluoride particles on the aluminum plate; under equivalent conditions, the uncoated aluminum plate temperature reached 373 K. The materials used in the coatings were characterized by wavelength-dependent infrared absorption and emission properties. Although the overall emissivity in wide wavelength range is previously considered to be the most crucial variable in radiative cooling, materials have specific infrared absorption and emission properties depending on their physical structures. Therefore, elucidating the relationship between the characteristics of an individual heat emission material and its cooling effects is necessary in order to design more effective heat dissipation measures based on radiation. It was confirmed that the selection of an appropriate filler material with specific infrared emission properties corresponding to the emitting wavelength at the given temperature of the objects to be cooled was important. Distinctive radiative cooling effects were thus obtained, even in the relatively low-temperature range examined here, by the selection of appropriate materials with radiative properties in the temperature range of interest.

Effects of inorganic fillers on withstanding short‐time breakdown and long‐time electrical aging of epoxy composites

Inorganic fillers were added to epoxy resin for preparing micro and nano filler/epoxy composite, and then the breakdown strengths, depths of erosion caused by partial discharge, and electrical tree experiments of composites were investigated. It was found that the loading of micro fillers usually decreases the short‐time breakdown strength (breakdown under a continuously rising voltage) of the composites. On the contrary, it increases the ability to withstand long‐time electrical aging (erosion or breakdown caused by electrical tree under a discontinuously rising voltage or constant voltage) of the composites. The effect of inorganic fillers in suppressing the electrical tree or erosion channel propagation in the composite is different during the process of withstanding short‐time breakdown and long‐time electrical aging. Defects are introduced during the mixing of fillers and epoxy resin, which play a role to decrease the short‐time breakdown strength and accelerate long‐time electrical aging. It is concluded that micro and nano inorganic fillers can suppress the electrical tree channel propagation and erosion caused by partial discharge, whereas defects play the opposite role in composites. Two opposite effects of inorganic fillers and defects exist simultaneously during the process of electrical aging and breakdown; whereas inorganic fillers play a primary role in long‐time electrical aging, defects play a primary role in short‐time breakdown.

TiO2 as conductivity enhancer in PVdF-HFP polymer electrolyte system

Composite polymer electrolytes were prepared by incorporating inorganic filler TiO2 into PVdF-HFP-PMMA-EC-LiClO4 system. The electrolyte films were prepared by solvent casting technique. The effect of inorganic filler on the conductivity of the blended polymer electrolyte was studied and it is found that there is a considerable increase in ionic conductivity 1.296 × 10-3 S/cm-1 on the addition of TiO2. X-ray diffraction (XRD) study elucidate the increase in amorphous nature of the polymer electrolyte. This tendency of the polymer electrolyte could be the reason behind the increase in ionic conductivity. Fourier transform infrared spectroscopy (FTIR) spectra show the occurrence of complexation and interaction among the components.