Effect Of Hybrid Fillers Research Articles

Effect of Hybrid Filler, Carbon Black-Lignocellulose, on Fire Hazard Reduction, including PAHs and PCDDs/Fs of Natural Rubber Composites.

The smoke emitted during thermal decomposition of elastomeric composites contains a significant number of carcinogenic and mutagenic compounds from the group of polycyclic aromatic hydrocarbons, PAHs, as well as polychlorinated dibenzo-p-dioxins and furans, PCDDs/Fs. By replacing carbon black with a specific amount of lignocellulose filler, we noticeably reduced the fire hazard caused by elastomeric composites. The lignocellulose filler reduced the parameters associated with the flammability of the tested composites, decreased the smoke emission, and limited the toxicity of gaseous decomposition products expressed as a toximetric indicator and the sum of PAHs and PCDDs/Fs. The natural filler also reduced emission of gases that constitute the basis for determination of the value of the toximetric indicator WLC50SM. The flammability and optical density of the smoke were determined in accordance with the applicable European standards, with the use of a cone calorimeter and a chamber for smoke optical density tests. PCDD/F and PAH were determined using the GCMS-MS technique. The toximetric indicator was determined using the FB-FTIR method (fluidised bed reactor and the infrared spectrum analysis).

Effect of Hybrid Fillers on Electrical, Thermal and Mechanical Properties of Glass Epoxy Composites

Failure of composites in various industrial applications has directed the requirement for further improvement in the electrical, mechanical, and thermal characteristics of polymers to meet the challenging requirements of the industry. In this study, different fillers namely SiO2, Al2O3, SiC, MoS2, graphite and cenosphere have been incorporated into the ECR glass fabric reinforced epoxy matrix. To exploit the application of these composites for electrical applications, the V-I characteristics is determined with a voltage range of 1V to 20V and impedance of the composites were determined in the range of 20 Hz to 10 MHz, at 25, 50 and 75±2°C. Also, an attempt is made to investigate the mechanical and thermal properties of composites. Composite with 5 wt.% of graphite filler has a maximum surface and volume current of 1.4nA and 0.05nA with a DC voltage that varies from 1V to 20V. Thermal stability improves in 10 wt.% of silicon carbide and 5wt.% of silica (nano and micro filler) at 70 and 80% weight loss, respectively. The glass epoxy with alumina has the highest density of 2.12 g/cm3. The highest value of hardness is achieved in 10 wt.% of cenosphere composite over the base material.

Performance Evaluation of Green Cushion Gum Composite Formulated Based on Hybrid Filler and Curing System

Cushion gum is a type of rubber composite material used as adhesive in the manufacture of retread tires. Therefore, cushion gum should have good processability and mechanical characteristics, particularly tensile property, and adhesion strength. The effect of hybrid filler and curing system on the performance of green cushion gum composite was investigated to determine the appropriate green cushion gum formula designed at a laboratory scale. The content of CB N330/lignin in hybrid filler was arranged at 40/10 phr and 50/10 phr. Meanwhile, the curing system was performed semi-efficient (CBS/S 1.6/1.6 phr) and conventional (CBS/S 1.6/2.2 phr). Green cushion gum composite was also formulated using pine tar oil as a bio plasticizer. Referred to the curing characteristic and mechanical property test result, it showed that green cushion gum composite formula coded by RF1 which composed of CB N330/lignin as 50/10 phr and applied conventional curing system which ratio of CBS/S as 1.6/2.2 phr was regarded as the acceptable combination in designing green cushion gum composite formula. Higher CB N330 loading in hybrid filler composition and conventional curing system attributed to the relatively high crosslink density indicated by MH-ML value. Consequently, green cushion gum composite was obtained using the RF1 formula that has a better optimum curing time accompanied by good tensile property and adhesion strength. The composite was also comparable to conventional commercial cushion gum.

Effect of Hybrid Fillers of Bamboo Fiber and Commercial Glass Fiber on High Density Polyethylene Matrix

The focus of this research work is to study the effect of hybrid fillers of bamboo fiber and commercial glass fiber on high density polyethylene (HDPE) matrix without interfacial coupling agent. The hybrid composite was formed through melt blending method using two-roll mixing mill at temperature of 160 oC and was shaped using compression molding machine. The highest value of Tensile Modulus at break and Hardness were obtained at hybrid ratio of 70 % of HDPE/ 15 % bamboo/ 15 % glass particles (H/B15/G15). However, the inclusion of the hybrid fillers did not show any significant difference in Impact strength from the molded blank HDPE samples (H/B0/G0) while the percentage water absorbed by the samples predominantly decreased as the content of the commercial glass filler was increase in the HDPE matrix.

Synergistic effect of hybridized TNT@GO fillers in CTA-based mixed matrix membranes for selective CO2/CH4 separation

Titanium dioxide nanotube (TNT) amalgamated graphene oxide (GO) matrix was blended with cellulose triacetate (CTA) polymer to form a new kind of mixed matrix membranes (MMMs) for the selective biogas upgrading. The effect of hybrid fillers on the physico-chemical, thermal and mechanical properties of membranes were studied using different spectroscopic techniques. Notable improvements on these properties were observed on MMMs as compared to the pristine membrane. Similarly, resulting MMMs exhibited higher CO2 adsorption affinity. Furthermore, single gas permeation measurements revealed higher permeability as well as selectivity for [email protected]/CTA membrane. CO2 permeability increased almost 7 times, reaching 22.54 Barrer, whereas CO2/CH4 selectivity increased nearly three folds from 25.06 for the pristine membrane to 86.69 for [email protected]/CTA membrane and reached the Robeson 2008 upper bound. The long term stability experiment of the [email protected]/CTA membrane confirm the anti-aging ability suggesting its practical application in the bio/natural gas upgrading process. These results established an effective modification approach for applying alternative porous hybrid fillers into gas separation applications.

Effect of Hybrid Fillers on the Bandgap Energy of Glass Epoxy Composites

Polymer composites are used increasingly in industrial applications due to their outstanding electrical, thermal, and mechanical properties. There is a vast literature on the advantages and limitations of nano and micro fillers and the effects of fillers on different properties of the polymers are reasonably understood. However, such information on the effects of a hybrid combination of nano and micron fillers is limited. In this investigation, the effect of hybrid fillers has been investigated in terms of the microstructure, optical absorption and electrical properties namely dielectric constant, AC conductivity and AC breakdown strength. Though different fillers are used, the bandgap energy varies over a narrow range of 2.5–3.2 eV. The hybrid fillers tend to influence the crystallinity and impart divergent optical absorbance spectra. The dielectric properties reveal dependence on the nature of the fillers and there are marked differences between the effects of conductive and insulating fillers, while the same is not observed in the case of the optical absorption spectra.

Effect of Hybrid Fillers on GFRP Epoxy Composites with Water Immersion and Thermal Conditioning

AbstractGlass fiber reinforced epoxy composite with graphene nanoplatelets, multi‐walled carbon nanotubes, and aluminium trihydrate fillers are fabricated by the pultrusion method. The role of fillers in complementing each other, improving the dielectric properties of the epoxy matrix is not fully understood. The objective of this work is to investigate the effects of nano and micro fillers combination by short‐duration laboratory ageing techniques. A comparison of aged and unaged specimen is carried‐out by impedance spectroscopy and gravimetric analyses. The dielectric properties are observed to be dependent on the interaction between the fillers and the epoxy matrix, also on the relative permittivity of individual nanofillers, dissolved ions that diffuse with water into the bulk of the composites. The composite specimens are immersed in distilled water up to 360 h for water ageing and the temperature is varied from 25 °C to 200 °C for thermal ageing. The impedance spectroscopy of the composites is measured over the frequency range (10 Hz–8 MHz). The observed reduction in the impedance values indicate that dipolar polarization is occurring due to absorbed water molecules during water immersion and mobilization of free electrons is taking place due to an increase in temperature. This study indicates that the effect of ageing can be quantified in terms of changes in the impedance spectra. From the results obtained, the effect of fillers is implicit since diffusion coefficient values are reduced from 5.58 × 10−9 m2 s−1 of the base epoxy composite to 3.48 × 10−9 m2 s−1 in hybrid nanocomposites. The percentage of water absorption at equilibrium condition is reduced from 0.68% to 0.46% of the total mass.

Properties improvement of acrylic resin for denture application: effect of single and hybrid types of fillers with different weight loadings

ABSTRACT This research aims to identify the suitable and optimum filler loading to improve the polymethyl methacrylate (PMMA) properties for denture application. Mechanical properties were determined based on the flexural, fracture toughness, hardness and impact strength. The first stage investigated the effect of different weight loadings of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP). The addition of 2 wt-% HA in PMMA composites increased the flexural and fracture toughness when compared with β-TCP composites. The addition of β-TCP in PMMA composites increased the mechanical properties at higher filler loading; 4 and 6 wt-%. The second stage investigated the effect of hybrid fillers; HA/polylactic acid (PLA) microsphere and HA/alumina (Al2O3). HA/PLA microsphere in PMMA showed 5% and 23% improvement on the fracture toughness and impact strength if compared to PMMA/2 wt-% HA. HA/Al2O3 in PMMA showed higher flexural strength. The mechanical properties of a single filler can be further improved by hybrid fillers.

High thermal conductivity, UV-stabilized poly(3-hydroxybutyrate-co-3-hydroxyvalerate) hybrid composites for electronic applications: effect of different hybrid fillers on structural, thermal, optical, and mechanical properties

ABSTRACT PHBV composites with three different hybrid fillers were prepared in which composites with BN/graphene tubes (0.5/1.5) and AlN/graphene tubes (0.5/1.5) exhibit high thermal conductivity (0.4985 W/mK, 0.5215 W/mK), UV/NIR absorption, thermal stability (~267°C), hardness (83D, 82D), storage modulus (2111 MPa, 2322 MPa), low CTE (~47 µm/m °C, ~49 µm/m °C) and roughness (0.105 µm, 0.141 µm) compared to Al2O3/BN composites and virgin PHBV. This enhancement is due to the synergetic effect of hybrid fillers in the PHBV matrix. Overall, prepared PHBV composites may be used for future bio-based USB, SD card and SSD enclosure applications.

Synergetic effect of micro-hBN and nano-Al2O3 fillers on structural, surface, thermal, and mechanical properties of PLA/hBN/Al2O3 hybrid composites: experimental and theoretical investigation

ABSTRACT PLA/hBN/Al2O3 hybrid composites with 1–30% filler concentrations were prepared in which composites with 1–2% fillers exhibit high tensile strength & modulus (8–22%, 2–12%), flexural strength & modulus (10–21%, 5–16%), storage modulus (1–14%), Tg & thermal stability (4°C, 4%), scratch hardness (37–48%), with very low CTE (22–25% & 58–66%) & surface roughness (81–97%) compared to all other samples. This improved mechanical, thermal, and decreased CTE were due to synergetic effects of hybrid fillers in the PLA matrix. The extruded filaments with 1% hybrid fillers can be used for the mass production of future bio-based substrates and enclosures.

Epoxy‐based composite adhesives: Effect of hybrid fillers on thermal conductivity, rheology, and lap shear strength

Thermal management is an important parameter in an electronic packaging application. In this work, three different types of fillers such as natural graphite powder (Gr) of 50‐μm particle size, boron nitride powder (h‐BN) of 1‐μm size, and silver flakes (Ag) of 10‐μm particle size were used for thermal conductivity enhancement of neat epoxy resin. The thermal properties, rheology, and lap shear strength of the neat epoxy and its composite were investigated. The analysis showed that the loading of different wt% of Gr‐based fillers can effectively increase the thermal conductivity of the epoxy resin. It has also been observed that the thermal conductivity of the hybrid filler (Gr/h‐BN/Ag) reinforced epoxy adhesive composite increased six times greater than that of neat epoxy resin composite. Further, the viscosity of hybrid filler reinforced epoxy resin was found to be increased as compared with its virgin counterpart. The adhesive composite with optimized filler content was then subsequently subjected to determine single lap shear strength. The degree of filler dispersion and alignment in the matrix were determined by scanning electron microscopy (SEM) analysis.

Hybridization Effect of Micro Fillers on Mechanical, Thermal and Morphological Behavior of PA66/PP Blend Based Hybrid Thermoplastic Composites

This article deals with the effect of hybrid fillers on mechanical, thermal and morphological behavior of hybrid fiber reinforced thermoplastic composite materials. Three material systems were selected: 80 wt% Polyamide66 and 20 wt% Polypropylene (PA66/PP) compatibilized blend as matrix (Blend), 10 wt% short glass fibers and 10 wt% short basalt fibers reinforced blend (BG) and micro fillers (PTFE, SiC and Alumina) filled hybrid composites (BGF). These composite materials were prepared by melt mix method with the help of twin screw extrusion technique. The mechanical properties were studied through tensile, flexural and impact behavior as per ASTM methods. Experimental results revealed that the effect of hybrid fibers enhanced greatly in terms of tensile and flexural behavior. But slight decrease in impact strength was observed. But the addition of micro fillers into hybrid fiber filled composites slightly decreased the strength of the composites. This might be due to the loss of ductility as a result of filler addition. The thermal stability of composites was studied through DSC technique to analyze the degree of crystallinity. But the effect of reinforcements decreased the degree of crystallinity due to loss in enthalpy. Further, the thermal stability of composites was studied through TGA. This study proved that the effect of reinforcement acted as resistance to weight loss of composites at different temperatures. The morphological study of the fractured surfaces of the composites through scanning electron microscope (SEM) images indicated that the fiber pull out and fiber fracture were the reasons for the failure of composite materials.

Exploration of the nanostructures and separation properties of cross-linked mixed matrix membranes using multiscale modeling

A new simulation scheme was established for strategically constructing cross-linked organic-inorganic mixed matrix membrane materials. This is a multiscale method using customized programming to effectively model complicated nanostructures. The effects of hybrid fillers in the chitosan/graphene oxide composite membranes are systematically elucidated at the molecular scale. Observed from the radial distribution function analysis, the significant enhancement of the separation performance in the dehydration of alcohols can be attributed to the stabilized polymer chains and the conspicuous increase in the water adsorption from mixing with graphene oxide sheets. Results show that the simulated models agree well with the experimental works in membrane density and transfer behavior of vapor molecules, which demonstrate that the modeling tools can be applied to evaluate the performance of cross-linked mixed matrix membranes, and to design various combination of hybrid membranes.

Graphene Nano-sheets/Multi-walled Carbon Nanotubes/Polyvinyl Alcohol Composite Films: Effects of Hybrid Fillers on Electromagnetic Interference Shielding Effectiveness

This study employs the solution mixing method to produce composite films by using polyvinyl alcohol (PVA), graphene nano-sheets (GNs), and multi-walled carbon nanotubes (MWCNTs). Tensile test, differential scanning calorimetry (DSC), four-point probe/coaxial transmission line method are performed in order to evaluate the tensile properties, melting and crystallization behaviors, electric conductivity, and electromagnetic interference shielding effectiveness (EMI SE) of the composite films. The test results indicate that with the increasing amount of MWCNTs, GNs/MWCNTs hybrid fillers cause a synergy effect that contributes to the tensile strength of the composite films. An optimal GNs/ MWCNTs ratio is 0.5 wt%:1wt% that provides the films with a tensile property of 19.6 MPa, an improvement on glass transition temperature (Tg), melting temperature (Tm) and crystallization temperature (Tc) of PVA, an electric conductivity of 2.6×10-5 S/cm, and EMI SE of -15 dB at frequency 1 GHz-2 GHz that is equal to a 99.9 % shielding level required by livelihood necessities.

Crystallization Kinetics of PP/Talc/Coir Hybrid Composites

Polypropylene (PP), a versatile polymer finds application in many sectors. However, it has low impact strength.To overcome this draw back elastomer is added, which results in improved impact property at the expense of decreased tensile strength. To improve this fillers are added. However some fillers also improve impact strength. In this work only fillers have been used to get balance of properties in PP. Knowledge of crystallization of PP is important for processing of PP. In this work the effect of hybrid fillers on PP has been studied on the isothermal and non-isothermal crystallization kinetics of PP. The fillers used are coir and talc.

Electrical conductivity and electromagnetic interference shielding effectiveness of carbon black/sisal fiber/polyamide/polypropylene composites

ABSTRACTThe effects of hybrid fillers on the electrical conductivity and electromagnetic interference (EMI) shielding effectiveness (SE) of polyamide 6 (PA6)/polypropylene (PP) immiscible polymer blends were investigated. Carbon black (CB) and steam exploded sisal fiber (SF) were used as fillers. CB was coated on the surface of SF, and this was exploded by water steam to form carbon black modified sisal fiber (CBMSF). CB/SF/PA6/PP composites were prepared by melt compounding, and its electromagnetic SE was tested in low‐frequency and high‐frequency ranges. We observed that SF greatly contributed to the effective decrease in the percolation threshold of CB in the PA6/PP matrix and adsorbed carbon particles to form a conductive network. Furthermore, an appropriate CB/SF ratio was important for achieving the best shielding performance. The results indicate that CBMSF was suitable for use as electronic conductive fillers and the CB/SF/PA6/PP composites could be used for the purpose of EMI shielding. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42801.

Properties of calcium copper titanate and barium titanate filled epoxy composites for electronic applications: effect of filler loading and hybrid fillers

Inorganic ceramics such as calcium copper titanate, CaCu3Ti4O12 (CCTO) and barium titanate (BaTiO3) were used as fillers to produce epoxy thin film composites for capacitor application. The effects of filler types and loading range on the dielectric, tensile, morphology, and thermal properties of the epoxy thin film composites were determined. Results showed that epoxy thin film composites with 20 vol% filler loading of CCTO and BaTiO3 showed good dielectric properties, thermal stability, and thermal conductivity. However, the tensile properties of the CCTO/epoxy thin film composite was reduced as the filler loading increased. On the other hand, the tensile properties of BaTiO3/epoxy thin film composite improved as the filler loading increased. Hybrid fillers CCTO and BaTiO3 filled epoxy composites were fabricated and the effect of hybrid fillers on the dielectric properties and morphology of the epoxy thin film composites were investigated. Results indicated that positive hybrid effect in dielectric constant and dielectric loss showed by the hybrid composites.

Effects of hybrid fillers on the electromagnetic interference shielding effectiveness of polyamide 6/conductive filler composites

The effects of hybrid conductive fillers on the electrical conductivity and electromagnetic interference shielding effectiveness (EMI SE) of polyamide 6 (PA6)/conductive filler composites were investigated. Nickel-coated carbon fiber (NCCF) was used as the main filler and multi-walled carbon nanotube (MWCNT), nickel-coated graphite, carbon black, and titanium dioxide (TiO2) were used as the second fillers in this study. From the results of morphological studies of the PA6/NCCF/second filler composites, NCCF easily formed an electrical pathway since it has a high aspect ratio and random orientation, and the second fillers seemed to disperse evenly in the PA6 matrix. The electrical conductivity and EMI SE of the PA6/NCCF composites were increased with the increase of NCCF content. Among the second fillers used in this study, TiO2 appeared to be the most effective second filler with regard to increasing the EMI SE and electrical conductivity of the PA6/NCCF composite. This was probably because TiO2 has a high dielectric constant with dominant dipolar polarization, consequently leading to greater shielding effectiveness due to the absorption of electromagnetic waves. From the above results of EMI SE and electrical conductivity, it was suggested that the TiO2 produced a synergistic effect when it was hybridized with the NCCF of the PA6/NCCF/TiO2 composites.

Effects of hybrid fillers on the electrical conductivity and EMI shielding efficiency of polypropylene/conductive filler composites

In this study, the effects of hybrid fillers on the electrical conductivity and electromagnetic interference shielding efficiency (EMI SE) of the polypropylene (PP)/Ni-coated carbon fiber (NCCF) composites with the second fillers, such as multi-walled carbon nanotube (MWCNT), carbon black and TiO2, were investigated. The morphological behavior showed that the NCCF and the second fillers, such as MWCNT, carbon black and TiO2, seemed to disperse evenly in the PP phase. Among the PP/NCCF composites with MWCNT, carbon black and TiO2, the PP/NCCF/TiO2 composites showed the higher electrical conductivity and EMI SE compared with those of the PP/NCCF/MWCNT and PP/NCCF/carbon black composites. This was the case because TiO2 has high dielectric constant with dominant dipolar polarization. The estimated EMI SE values of the PP/NCCF composites with MWCNT, carbon black and TiO2 are in good agreement with the experimentally obtained values of the composites. Based on the electrical properties of the composites, it was suggested that TiO2 was the most effective second filler when it was hybridized with the NCCF of the PP/NCCF/TiO2 composite. Based on the analysis of the flexural modulus, the PP/NCCF/MWCNT composite had a higher flexural modulus than the PP/NCCF/TiO2 and PP/NCCF/carbon black composites because of the higher aspect ratio of the MWCNT. Open image in new window

A Novel Polymeric Coating with High Thermal Conductivity

A novel polymeric coating with high thermal conductivity was prepared using a hydroxyl-terminated polydimethylsiloxane-modified epoxy resin and hybrid aluminum nitride (AlN) particles with various sizes. It was found that the coating exhibited a maximum thermal conductivity of 1.78 W/m K at 50 wt% filler content and a preferable mass ratio. This was a result of the synergistic effect of hybrid fillers giving rise to a better heat conduction capability as opposed to a coating without fillers. Furthermore, thermogravimetric analysis revealed that the coating exhibited an excellent high temperature resistance owing to the modified matrix and interaction between filler and matrix; and a dielectric study demonstrated that the dielectric constant, volume resistivity and dielectric strength of the coating at 50 wt% filler concentration were 5.6, 8.2 × 1013 Ω·cm and 12 kV/mm, respectively. In addition, the mechanical properties declined obviously with filler content.