M. Mariatti

Tensile, dielectric, and thermal properties of epoxy composites filled with silica, mica, and calcium carbonate

The minerals silica, mica, and calcium carbonate (CaCO3) were used as fillers to produce epoxy thin film composites for capacitor application. The effects of filler loading and type on the morphology, tensile, dielectric, and thermal properties of the epoxy thin film composites were determined. Results showed that epoxy thin films with 20xa0vol% filler loading showed good dielectric properties, thermal conductivity, and thermal stability. However, the tensile properties of the thin films were reduced as the filler loading was increased due to brittleness. Dielectric constant and dielectric loss of epoxy/inorganic composite films generally increased with increasing mineral filler loading. Meanwhile, the presence of mineral filler improved the thermal stability of the thin film composites. The highest dielectric constant of 5.75 with 20xa0vol% filler loading at a frequency of 1xa0MHz was exhibited by the epoxy/CaCO3 composite, followed by epoxy/mica and epoxy/silica. Therefore, the epoxy/CaCO3 composite is the most potential candidate for capacitor application. Moreover, precipitated CaCO3 provided better tensile properties and slightly improved the dielectric properties compared with mineral CaCO3.

Effects of hybrid fillers based on micro- and nano-sized silver particles on the electrical performance of epoxy composites

In the present study, electrically conductive adhesives produced from hybrid fillers based on micro- and nano-sized silver (Ag) was developed. The influence of the hybrid filler composition on the electrical properties of the hybrid system was studied. The electrical conductivity of the epoxy composites filled with micro- and nano-silver was correlated with their morphologies. A positive effect was observed in the electrical conductivity result when the composition of micro- and nano-sized Ag particles reached a 50:50 weight ratio. The nano-sized Ag particles became interconnecting particles in the interstitial spaces between micro-sized particles. Micrograph scanning shows that the particles were well distributed and dispersed, the separation between lumps of Ag filler by the insulating matrix was significantly reduced, leading to the formation of continuous linkages. The increased electrical conductivity resulted in a charge around the particle distribution, which led to the high capacity. Hence, these particles increased the conductivity of the system.

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 20xa0vol% 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.

Effect of Ethanol as Diluent on the Properties of Mineral Silica Filled Epoxy Composites

Epoxy composites with mineral silica containing 0—60 vol% were prepared using a mechanical stirrer. Ethanol at 10wt% was used as the diluent in the epoxy system. The mechanical properties of epoxy composites were studied through flexural and single etch notch tensile mode (SEN-T) fracture toughness tests. Scanning electron microscopy (SEM) was used to assess the flexural fracture surface morphology. The thermal properties were characterized using a dilatometer, dynamic mechanical analyzer (DMA), and thermogravimetric analysis (TGA). In general, it is found that the properties of epoxy composites are governed by the filler loading and the addition of ethanol as the diluent. The addition of the diluent in epoxy permits higher amount of filler content in the epoxy composites system, i.e., 60vol%, compared to that of the non-diluent system at 40vol%. In short, higher filler loading present in a diluent system results in higher stiffness and low coefficient of thermal expansion (CTE) as required in the electronic packaging application.

Graphene nanoparticle dispersion in epoxy thin film composites for electronic applications: effect on tensile, electrical and thermal properties

Graphene nanopowder (GNP)/epoxy thin film composites were fabricated using an ultrasonication and spin-coating technique. This study aims to investigate the effect of dispersion state and filler loading (0.025–1xa0vol%) of GNP on the tensile, electrical and thermal properties of the GNP/epoxy composites. GNP/epoxy composites with different dispersion states were prepared, and a combination of sonication and chloroform (as the dispersion solution) was used in one of the samples. The addition of GNP decreased the tensile properties of the epoxy composites. However, among the tested samples, the chloroform GNP (ch-GNP)/epoxy composites had higher tensile properties, especially at low filler loading (0.05–0.2xa0vol%). Although the ch-GNP/epoxy formed clusters, a higher degree of dispersion and exfoliation of GNP was observed in each cluster, due to improve dispersion by chloroform compared to the system without chloroform. The rolling of GNP was found to be dominant in the ch-GNP/epoxy composite. Electrical properties showed that the ch-GNP/epoxy composites exhibit higher electrical conductivity with lower percolation thresholds value than that the GNP/epoxy composites. From the thermal properties it was determined that composites with the dispersion solution showed a higher glass transition temperature (Tg) than those without the dispersion solution.

Dielectric and thermal properties of CCTO/epoxy composites for embedded capacitor applications: mixing and fabrication methods

In this study, calcium copper titanate, CaCu3Ti4O12 (CCTO) was used as filler in epoxy composite using different mixing and fabrication methods to investigate their suitability as dielectric materials for embedded capacitor. Results show that 20xa0vol% CCTO/epoxy composite produced using ultrasonic mixing method yield slightly higher dielectric constant, T5% and Tonset as compared to 20xa0vol% CCTO/epoxy composite produced using agate mortar method. Meanwhile, sample with 20xa0vol% CCTO/epoxy composite fabricated using spin coating method shows slightly higher dielectric constant, T5%, Tonset and E′, and lower CTE value compared to 20xa0vol% CCTO/epoxy composite fabricated using hot press method. Nevertheless, 40xa0vol% CCTO/epoxy composite fabricated using hot press method shows the highest dielectric constant, T5%, Tonset and E′, and lowest CTE value compared to all composites. In short, composite produced using ultrasonic as mixing method and spin coating as fabrication method are suitable to be utilized to produce epoxy composite as dielectric materials for embedded capacitor applications.

Nano-sized boron nitride epoxy composites for underfill application: effect of diluent and filler loading

Effect of ethanol as diluent in the preparation of nano-sized boron nitride filler filled epoxy composites was investigated. Ethanol at 10xa0wt% was used to reduce the viscosity of epoxy composites. Filler loading up to 6xa0vol% is able to be added in the diluent system, as compared to 4xa0vol% in the non-diluent system. Sonication process was used to facilitate filler dispersion. At 4xa0vol% filler loadings, diluent system showed 36xa0% higher in flow rates than non-diluent system. Apparently, non-diluent system showed higher flexural strength, modulus, thermal conductivity, and lower coefficient of thermal expansion (CTE) than that of diluent system. However, when the filler loading is up to 6xa0vol% for the diluent system, CTE is reduced 4.3xa0% and thermal conductivity increased 6.9xa0% if compared to 4xa0vol% non-diluent system. In general, it is concluded that diluent system at 6xa0vol% exhibit better flowability, CTE and thermal conductivity to fabricate underfill materials.

Dielectric properties and thermal properties of calcium copper titanate and barium titanate hybrid fillers filled epoxy thin film composites for electronic packaging applications

Ceramic fillers such as calcium copper titanate, CaCu3Ti4O12 (CCTO) and barium titanate (BaTiO3) were used as hybrid fillers to produce hybrid thin film composites for electronic packaging applications. Results indicated that positive hybrid effect in dielectric and thermal properties showed by the hybrid composites. Hybrid fillers with the ratio of 70:30 of CCTO:BaTiO3 filled epoxy thin film composite exhibited the highest dielectric constant, lowest coefficient thermal expansion value, moderate thermal stability and dynamic mechanical properties compared to those of hybrid composites with the ratio of 30:70 and 50:50, unfilled epoxy, 20 CEC and 20 BEC, respectively.

Fabrication of silica/epoxy thin film composite for electronic packaging application

Conventional packaging technology has been replaced in line with the miniaturization trends of the product designs in electronic industry. A polymer resin needs to suit to certain polymer processing methods in order to achieve substantial performance in terms of mechanical, thermal, optical, electrical and so forth. In this study, an epoxy based thin film composite was successfully fabricated by using the spin coating method. Comparing this with the conventional method such as dip coating, solution casting and hot pressing methods, spin coating fabrication method allows controllable-uniform thickness ranging from micron to nanometer. In order to enhance the thermal, mechanical and its dimensional stability, two types of silica fillers which are in micron and nano-sized were studied. The nano-sized silica was found to further enhance the properties of the epoxy thin film at low weight fraction. This is due to its higher ratio of surface area to volume compared to the micron-sized silica.

Enhancement of thermal and electrical conductivities of cyanoacrylate by addition of carbon based nanofillers

Nanocomposites with addition of graphite nanoparticles, multi-walled carbon nanotubes (MWCNTs), and graphene in cyanoacrylate from 0.1 to 0.5 or 0.6xa0vol% were fabricated. The influences of morphology towards thermal and electrical conductivities of cyanoacrylate nanocomposites were studied. Microstructure based on field emission scanning electron microscopy and transmission electron microscopy images indicated that nanofillers have unique morphologies which affect the thermal and electrical conductivities of nanocomposites. The maximum thermal conductivity values were measured at 0.3195 and 0.3500xa0W/mK for 0.4xa0vol% of MWCNTs/cyanoacrylate and 0.5xa0vol% of graphene/cyanoacrylate nanocomposite, respectively. These values were improved as high as 204 and 233% as compared with the thermal conductivity of neat cyanoacrylate. Nanocomposites with 0.2xa0vol% MWCNTs/cyanoacrylate fulfilled the requirement for ESD protection material with surface resistivity of 6.52u2009×u2009106xa0Ω/sq and volume resistivity of 6.97u2009×u2009109xa0Ωxa0m. On the other hand, 0.5xa0vol% MWCNTs/cyanoacrylate nanocomposite can be used as electrical conductive adhesive. Compared with graphene and graphite nanofillers, MWCNTs is the best filler to be used in cyanoacrylate for improvement in thermal and electrical conductivity enhancement at low filler loading.