Mica Fillers Research Articles

Damping materials based on plasticized polybutyl methacrylate, polymethyl methacrylate and polyvinyl acetate

The purpose of the presented work is to investigate by DMA method the influence of the composition of filled and unfilled plasticized compositions based on polyvinyl acetate (PVA), polybutyl methacrylate (PBMA) and polymethyl methacrylate (PMMA) on their damping characteristics. It was found that when plasticizer is introduced into the polymer, the value of the mechanical loss coefficient first increases, reaches its maximum, and begins to decrease with further increase in the plasticizer content. The maximum effect is observed at a plasticizer/polymer volume ratio of 0.2-0.4. Two other dissipative characteristics, the temperature interval of effective damping and the integral coefficient of mechanical losses, are changing similarly. It is established that the additives of chlorinated paraffins in compositions based on PVA and PBMA can significantly improve their vibration absorbing characteristics. Introduction of mica filler into the composition of plasticized compositions based on PVA and PBMA does not lead to the appearаnсe of additional relaxation mechanisms. With increasing of the content of mica, the elastic modulus of compositions increases in the entire temperature range (especially significantly for compositions with a high content of plasticizer), the coefficient of mechanical losses slightly decreases, and the temperature practically does not change at which the maximum damping is observed.

Design, Fabrication, and Performance Analysis of Fire‐resistant Damping Polyurethane

AbstractTo improve the noise reduction and fire resistance of marine coating materials, some fire‐resistant polyurethane damping materials were prepared by varying the ratio of esterified branched polyols (EBP) and the 1,4 butanediol (1,4 BD), the content, and the particle size of the mica filler. The effects of branch chain, mica filler content, and particle size in polyurethane structure on the mechanical, dynamic mechanical properties, and fire resistance of polyurethane and its polymerization process were studied. The experimental results showed that the effective damping temperature range of polyurethane material widened from 42.1 °C to 76.6 °C, and then narrowed to 31.2 °C with the increase in EBP ratio. And the maximum loss factor (tanδmax) of these samples is 0.989. The increase of mica content and the decrease of mica particle size in polyurethane damping materials make the dynamic mechanical properties of polyurethane damping materials present a trend of first improving and then impairing. Moreover, the mechanical properties of polyurethane enhanced with the increase of EBP and weakened with the increase of mica mass fraction. This research is expected to advance the development of marine coatings and address noise reduction and fire protection challenges for marine materials.

Chemical and Mechanical Characterization of Unprecedented Transparent Epoxy–Nanomica Composites—New Model Insights for Mechanical Properties

Two nanomicas of similar composition, containing muscovite and quartz, but with different particle size distributions, have been used to prepare transparent epoxy nanocomposites. Their homogeneous dispersion, due to the nano-size, was achieved even without being organically modified, and no aggregation of the nanoparticles was observed, thus maximizing the specific interface between matrix and nanofiller. No exfoliation or intercalation has been observed by XRD, despite the significant dispersion of the filler in the matrix which produced nanocomposites with a loss in transparency in the visible domain of less than 10% in the presence of 1% wt and 3% wt of mica fillers. The presence of micas does not affect the thermal behavior of the nanocomposites, which remains similar to that of the neat epoxy resin. The mechanical characterization of the epoxy resin composites revealed an increased Young's modulus, whereas tensile strength was reduced. A peridynamics-based representative volume element approach has been implemented to estimate the effective Young's modulus of the nanomodified materials. The results obtained through this homogenization procedure have been used as input for the analysis of the nanocomposite fracture toughness, which has been carried out by a classical continuum mechanics-peridynamics coupling approach. Comparison with the experimental data confirms the capability of the peridynamics-based strategies to properly model the effective Young's modulus and fracture toughness of epoxy-resin nanocomposites. Finally, the new mica-based composites exhibit high values of volume resistivity, thus being excellent candidates as insulating materials.

Quantitative Leaching of Awo Mica Ore in Acetic Acid Solutions

Mica is mined and processed throughout the world and used as functional filler in many applications, such as in joint compound, electrical insulation, and plastics. The single most important feature of mica is high aspect ratio, the ratio of width to thickness. High aspect ratio mica filler is desirable in specialty applications, such as in automotive plastics, electrical industry. Considering these applications, Awo mica was quantitatively leached using acetic acid with focus on the determination of elemental composition of the ore using XRF technique, the determination of mineralogical purity of the ore using XRD, SEM and EDS techniques, the determination of the dissolution rate using acetic acid so as to predict the optimum conditions for the beneficiation of the ore for industrial applications and lastly, to investigate the potential for developing flake muscovite deposits in Southwestern Nigeria. Various parameters like effect of leachant concentration, temperature and the particle size have been investigated. Increase in leachant concentration and temperature brings about increase in dissolution rate and decrease in particle size increases the dissolution rate. The calculated reaction order and Activation energy (Ea) was 0.9437 and 21 kJ/mol respectively. The shrinking core model employed showed diffusion-controlled mechanism as the rate determining step for the dissolution process. Detailed ore characterization, for example the XRF for the elemental analysis shows that SiO2 is the most abundant compound (58.30%). It also contains other major compound like Al203 (18.70%) with the other detected compounds found to occur in minor to trace levels (< 1%). The residual product was quantitatively characterized by XRD and SEM instrumentations.

Mica filled polyetherketoneketones for material extrusion 3D printing

Polyetherketoneketone (PEKK) has superior physical properties to most available thermoplastics compatible with material extrusion-based 3D printing. The performance of fused filament fabrication (FFF) compatible PEKK has been detailed primarily as a function of varying the isomer ratios composing the co-polymer structure. PEKK composite or blend development for AM has received limited attention, yet this strategy is attractive for further performance tailoring and to address challenges associated, for example, with shrinkage upon crystallization. Here, we report the integration of three grades of mica platelets into PEKK at 10% and 30% mass loadings to generate an array of filament feedstocks that were used to print objects with a simple FFF machine. The effects of mica coating chemistry on the compatibility with PEKK and resulting properties are described. Mica fillers have only subtle influence on the FFF relevant melt rheological properties inherent to PEKK. Pigment micas at high loadings reduce the melting temperature of PEKK without shifting its glass transition temperature or inducing undesirable crystallization during processing. The printed composites were effectively cold crystallized post-printing similarly to unfilled PEKK resulting in increased dimensional stabilities. All micas, when used as fillers in low and high relative PEKK crystallinities, increased the tensile modulus of parts in correlation to the loading. The microstructural features of a printed composite were compared to unfilled PEKK by use of high-resolution helical micro-computed tomography. Practically, pigment micas can confer a wide range of rich colors to 3D-printed PEKK.

Polycarbonate/mica extrusion using mixing elements: Improvement of transparency and thermal, mechanical and water and gas barrier properties

Polycarbonate (PC) was loaded with mica fillers by melt mixing process using a twin-screw extruder. The influence of the mica content on the PC properties was analyzed. Also, the presence of mixing elements of grid shape on the mica distribution during the PC extrusion was discussed. These elements allowed us to significantly improve the fillers dispersion in the polymer matrix. As a consequence, the transparency of the PC films was maintained up to 5 wt% of mica due to reducing the aggregates formation and the homogeneous mica dispersion. Despite a slight decrease of the polymer molar mass, a strong improvement of the PC thermal stability, mechanical resistance as well as barrier properties towards water and gases (N2, O2 and CO2) was obtained due to the reinforce and tortuosity effects induced by mica fillers in the PC matrix. The gas and water transport properties of the PC/mica films were well-fitted using a predictive empirical model, that took into account the double tortuosity and immobility effect of mica particles. In addition, mica fillers were found to have specific interactions with water molecules, that led to enhancement of the moisture resistance of PC, thus improving its performance.

The Effect of the Modification of Mica by High-Temperature Mechanochemistry on the Anticorrosion Performance of Epoxy Coatings.

Epoxy resin was directly grafted onto the surface of mica powder by high-temperature mechanical ball milling. This method was used to achieve a chemical reaction between the epoxy resin and mica that cannot be carried out under conventional circumstances. The results show that an epoxy resin layer with a thickness of approximately 10 nm formed on the surface of the mica. This modified mica filler exhibited a significant change in its hydrophilic properties. The dispersion of mica and its compatibility with organic coatings also significantly improved. In addition, the modified mica filler was added to the epoxy coating. The improvement of the coating’s compactness and toughness is the reason for its anti-corrosion performance enhancement.

Optimization of the radiotransparent constructions in a mode of extreme heat loads

An experimental method has been developed for optimizing the composition of multilayer radiotransparent structures operating under extreme thermal loads. To optimize the composition of the layers of the radiotransparent radome researchers for the following materials with structures of the glass filler are carried out: glass-fiber laminate (GFR-CM), reinforced quartz material of SiO2–SiO2 class (HTRC-CM), organosilicon rubber with a ground mica filler (TCT). The parameters of the heat loads that cause physicochemical transformations in radiotransparent materials and significantly affect the transmission and reflection coefficients of materials, as well as their complex permittivity, are determined. It is shown that the decrease in the transmission coefficient for the construction made of HTRC-CM material is up to 3–4 dB in the frequency range from 2 to 40 GHz, and for constructions made of GFR-CM+TCT is up to 25 dB, respectively. As a result, the radome made of ceramic matrix composite HTRC-CM has the best radiotransparency characteristics.

Geopolymer synthetized using reactive or unreactive aluminosilicate. understanding of reactive mixture

This work aims to study the effect of the addition of reactive or unreactive aluminosilicate sources on the geopolymerisation reaction, and therefore on the geopolymer's working properties. To this end, six formulations with different metakaolin content, as well as the potential addition of mica fillers, were synthetized and investigated over time. The structural evolution of the reactive mixtures was monitored by FTIR spectroscopy and thermal analysis, whereas the resulting geopolymers were characterized using X-ray diffraction and 27Al NMR. Finally, SEM observations of the microstructures of the consolidated materials were carried out. The results show that a rise in the metakaolin content modifies the dissolution step of the geopolymer formation by decreasing the amount of consumed water from 50 to 34%. Moreover, it increases the initial viscosity by 66% and decreases the setting time by 168 min. Besides, with the addition of mica fillers, the analysis of the FTIR spectra outlines a lower reactivity of the mixture and the formation of several geopolymer networks, ultimately leading to a heterogeneous microstructure. Finally, the mechanical properties are directly related to the level of amorphous phase in the geopolymer sample, the highest values being reached for 85% of amorphous phase.

Prolonging electrical lifetime of mesogenic epoxy based alumina-mica composite sheet: Optimization of mica content by electrical tree progress simulation

Electrical lifetime of alumina-mesogenic epoxy composite sheet is improved by the addition of mica without reducing thermal conductivity. We developed an electrical tree progression simulation to optimize the composition ratio of four species of fillers (mica and three types of alumina fillers). This simulation is based on the electric field analysis with the use of a two-dimensional finite-difference method. The simulation revealed that the electrical lifetime of the composite sheet increases depending on the amount of mica filler although it is saturated at 1.3 vol. %. The calculated electrical lifetime of the sheet with mica filler is 1.5–2.0 times longer than that of the sheet without mica. This result agrees with the experimental at high applied voltage of 7 kVrms. A low mica ratio is suitable in the view of the thermal conductivity of the composite sheet because thermal conductivity of mica filler is much lower than that of alumina filler. The effective amount of mica filler was determined at 1.3 vol. % to possess high thermal conductivity and long electrical lifetime. As a result, a composite sheet with thermal conductivity of 8.7 W m−1 K−1 and the electrical lifetime 13 times longer than the sheet without mica at 4 kVrms was obtained.

Dielectric, thermal and morphological characteristics of Nitrile butadiene rubber under effect filler/hybrid filler

This paper worked to enhance the characteristics of Nitrile butadiene Rubber (NBR) such as dielectric, thermal characteristics for industrial applications, by adding different concentrations of industrial waste (quartz) and by-product (silica fume) from manufacture of ferrosilicon alloys in rubber matrix. the dielectric characteristics of NBR composites was studied by measuring dielectric strength, also studied the effect of hybrid filler on NBR composites by adding various concentrations of mica filler to the concentration of silica fume and quartz. The thermal characteristics of NBR composites were investigated in this work with filler and hybrid filler on NBR. The particle size and particle shape of silica fume and quartz was studied by using Transmission Electron Microscopy (TEM). For these composites the Scan Electron Microscopy (SEM) was done.

Electrical and mechanical properties of Nitrile rubber (NR) filled with industrial waste and by product from manufacture of ferrosilicon alloys in Egyptian chemical industries company

This work focused on using silica fume (by product) and quartz (industrial waste) in manufacture of ferrosilicon alloys in Egyptian chemical industries company (KIMA), in Aswan, Egypt. To reinforce the properties of Nitrile rubber, reduce cost and save the environment from industrial waste. Preparation rubber composites by addition different concentrations from silica fume filler (byproduct) and quartz filler (industrial waste). Investigation on the insulation properties of nitrile rubber composites by measurement of flashover voltage for unfilled nitrile rubber (blank) and nitrile rubber composites with silica fume filler and quartz filler. The measurement of flashover voltage for nitrile rubber composites occurred in different conditions (dry, wet, salinity and acidity). The effect of silica fume filler and quartz filler on mechanical properties of nitrile rubber was studied by investigation on elongation at break for nitrile rubber composites and also tensile strength. Studied the effect of hybrid filler on enhancement of electrical properties and mechanical properties of nitrile rubber, by addition different concentrations of mica filler on the samples showed the least enhancement in insulation properties of nitrile rubber composites in case of silica fume and quartz filler. And also study the morphology of nitrile rubber composites. http://ejchem.journals.ekb.eg/article_3828.html

PREPARATION AND CHARACTERIZATION OF EPDM RUBBER MIXTURE FOR A HEAT RESISTANT CONVEYOR BELT COVER

In this paper, the EPDM rubber-based dough recipe for a conveyor belt used in high temperature conditions was developed. As a first step, the silica loading effect on the mechanical and rheological properties was determined. After selecting the proper coating dough recipe, dough properties were investigated for filler mica, instead of silica, and the influence of paraffinic oil was tested for both silica and mica fillers. The properties of the EPDM rubber blend were investigated with rheometer tests on the semi-finished materials and with mechanical and physical tests (tensile strength, elongation at break, density, hardness, abrasion, heat ageing tests) on the finished coating materials after a vulcanization process. Thermal degradation behaviors of materials were analyzed by the thermal gravimetric analysis (TGA) system, and determination of chemical structure was analyzed by Fourier transform infrared spectroscopy (FTIR). The physico-mechanical characteristics of EPDM rubber blends were increased with silica loadings. EPDM rubber demonstrates thermal resistance in the temperature range of 150oC – 160oC under normal conditions. As a result of the studies conducted, the heat resistance of the coating rubber material was raised to 200oC by adding silica and paraffinic oil with a higher flash point into the EPDM dough mixture formulae.

Mechanical Properties of Mica-Filled Polycarbonate/Poly(Acrylonitrile-Butadiene-Styrene) Composites

The present study investigated the effect of untreated and treated mica fillers on the mechanical properties of Polycarbonate (PC)/Poly(Acrylonitrile-Butadiene-Styrene) (ABS) composites. PC/ABS/mica composites were prepared by using twin screw extruder and test samples by injection molding. Results indicated that incorporation of mica in PC/ABS (70/30) causes decreases in tensile stress, elongation at break, and on impact properties. It was observed that surface treatment of mica by a coupling agent on PC/ABS 70/30 composite displays increases in tensile stress, elongation at break, and on flexural strength and impact properties. Treated mica is utilized as filler in PC/ABS blends to enhance its application in electronic and automotive sectors.

A Study on the Influence of Compatibilizer and Mica Filler on the Properties of Thermoplastic Polyurethane/Polyolefins Blends

Improvement of mechanical and chemical properties can be achieved by melt blending of thermoplastic polyurethane (TPU) with polyolefins (PO's). Since TPU and PO's are completely immiscible polymers, property enhancement cannot be attained. Effect of incorporation of polypropylene copolymer (PPCP), TPU-g-MA, TPU-g-AA as compatibiliser on the miscibility of the blends and effect of mica filler to enhance the mechanical properties were studied. A single screw extruder was used to manufacture blends by melt mixing. The results of mechanical and morphological properties show that the blend of thermoplastic polyurethane (TPU)/PO's with suitable compatibiliser and mica gives excellent performance in all aspects.

Mechanical and Morphological Properties of Mica and Short Glass Fiber Reinforced Polyamide 6 Composites

In this study, the influence of short glass fiber and lamellar particle mica fillers on the mechanical properties of polyamide 6 was investigated. Reinforcement materials of 10 to 30% by weight were added to polyamide 6 polymers. Tests were carried out and the results showed that the strength and flexural modulus of the polyamide 6 composite increased with the increase in added short glass fiber and mica. However, tensile and flexural strength showed insensitivity to the increase in mica reinforcement content. Moreover, the impact strength and elongation at break values decreased with the increase in mica reinforcement ratio.

Effects of matrix molecular weight on structure and reinforcement of high density polyethylene/mica composites

Three types of high-density polyethylene (HDPE) with different molecular weights (high, medium and low) were adopted to evaluate the influence of matrix molecular weight on the structure-property relation of injection-molded HDPE/mica composites through a combination of SEM, 2d-WAXS, DSC, DMA and tensile testing. Various structural factors including orientation, filler dispersion, interfacial interaction between HDPE and mica, etc., which can impact the macroscopic mechanics, were compared in detail among the three HDPE/mica composites. The transcrystallization of HDPE on the mica surface was observed and it exhibited strong matrix molecular weight dependence. Obvious transcrystalline structure was found in the composite with low molecular weight HDPE, whereas it was hard to be detected in the composites with increased HDPE molecular weight. The best reinforcement effect in the composite with low molecular weight HDPE can be understood as mainly due to substantially improved interfacial adhesion between matrix and mica filler, which arises from the transcrystallization mechanism.

Effect of Concentration of Mica and Microsilica on Particulate Composites of Poly(ethersulfone) and Poly(ether-ether-ketone)

High performance polymers, poly(ether-ether-ketone) (PEEK) and poly(ethersulfone) (PES), were filled with mica and silica particulate fillers at different filler contents and the properties of the composites have been compared. The performance of these composites was analyzed in terms of the tensile, flexural, and impact properties and hardness measurements, and the properties were found to increase with increase in filler content. The scanning electron microscopy studies revealed that filler dispersion is good even at higher loadings. The dielectric strength, arc resistance, and heat distortion temperature of both mica- and microsilica-filled PEEK and PES composites are found to have better performance compared to unfilled polymers. Mica filler is found to be a better filler for PEEK than silica, while silica imparts better properties for PES than mica does.

Polyetheretherketone composites reinforced with surface modified mica

Mica fillers reinforced polyetheretherketone (PEEK) composites were fabricated using compression molding technique. To improve embedding of the mica within the PEEK matrix, the mica surface was chemically modified using vinyl trimethoxysilane (VTMO), at variable concentration (0–1.5 wt%). The performance characteristics and treated mica PEEK at mica loading of 20 wt% composites were examined in terms of scanning electron microscopy, dynamic mechanical thermal analysis, and modulated differential scanning calorimetry. The tensile strength and modulus improved to the tune of 81 and 44% with treated mica-filled PEEK composites. Mechanical tests revealed improved properties of VTMO-treated mica/PEEK composites, which confirmed improved interfacial adhesion with chemical treatment. The increment of the dynamic modulus for the treated mica PEEK composites was also noticed to 82% as compared with untreated counterpart, at elevated temperatures of 250°C, indicating apparent improvement of high-temperature mechanical properties. POLYM. COMPOS., 31:2121–2128, 2010. © 2010 Society of Plastics Engineers

Effect of different types of filler and filler loadings on the properties of carboxylated acrylonitrile–butadiene rubber latex films

AbstractThe effects of different types of fillers and filler loadings on the properties of carboxylated nitrile rubber (XNBR) latex were identified. Silica, mica, carbon black (CB; N330), and calcium carbonate (CaCO3) were used as fillers with filler loadings of 10, 15, and 20 parts per hundred rubber. Furnace ashing and Fourier transform infrared analysis proved that interaction existed between the fillers and XNBR latex films. The morphology of the filled XNBR films was significantly different for different types of fillers. Mica and CaCO3 fillers showed uneven distribution within the XNBR film, whereas other fillers, such as silica and CB, showed homogeneous distribution within the films. In the observation, silica and mica fillers also illustrated some degree of agglomeration. The mechanical properties (e.g., tensile and tear strengths) showed different trends with different types of fillers used. For silica and mica fillers, the mechanical properties increased with filler loadings up to a certain loading, and decreased with higher filler loadings. For CB filler, the mechanical properties increased gradually with increasing filler loadings. CaCO3 fillers did not increase the mechanical properties. The crosslinking density of the XNBR films increased when they were incorporated with fillers because of the presence of elastomer–filler and filler–filler interactions. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010