Particles In Epoxy Matrix Research Articles

Experimental Analysis of Mechanical and Thermal Characteristics of Luffa/Epoxy Polymer Composite under the Influence of Nanosilica

In the current work, the experimentations have been accomplished to assess the impact of diffusing nanosilica particles in epoxy matrix on the mechanical and thermal performance of the luffa fibre reinforced epoxy composite material. The matrix and fibre composition are fixed as 80 : 20 throughout the study, and the nanosilica is disbanded in diversified volume fractions of 0%, 0.5%, 1.0%, 1.5%, 2.0%, and 2.5%, respectively, while preparing luffa/epoxy/nanosilica (LES) composite samples. The mechanical characteristics, such as tensile, flexural, and impact behaviour of the composite, and the thermal properties, namely, thermal stability and thermal conductivity, are examined for the LES samples. The experiments are accomplished as per the ASTM standards. The results revealed that the assimilation of nanosilica particles in epoxy has improved the mechanical and thermal characteristics of the composite significantly. The tensile, flexural, and impact strength of the composite have been amended by 157.58%, 66.9%, and 16.5% with 1.5% addition of nanosilica in epoxy. Similarly, thermal conductivity of the composite is improved by 47.53% with the dispersion of 2.5% nanosilica in epoxy matrix. In addition, the thermal stability of the LES composite samples is substantially improved while disbanding nanosilica in epoxy matrix. However, the better results are reported for the LES composites containing 1.5% nanosilica content, compared to the next higher volume fractions of nanosilica content in epoxy matrix.

Thermal conductive behavior of zirconium boride coated by nanoalumina with different mass proportions in epoxy composites

The thermal conductive behavior of Zirconium diboride (ZrB2) coated with different proportions nanoalumina (Al2O3) in epoxy composites was investigated by the laser flash experimental and finite element analysis (FEA) methods. The coated ZrB2 composite particles were categorized into the 3-1, 3-2, 3-3 and 3-4 systems, which corresponded to four different mass ratios of ZrB2 particles to Al2O3 particles, respectively. It could be found that the coated ZrB2 composite particles were effective for increasing the thermal conductivity of the filled epoxy composites due to more effective formation of the conductive chain structure in the composites compared to the single-phase particles. In comparison, the system of 3-3 showed the most positive effect on improving the thermal conductive performance of epoxy composites. For composites with a 7 vol% of ZrB2/Al2O3 composite particles of 3-3 system, its thermal conductivity was 0.65 W m−1 K−1, increased by 20% and 79% relative to single-filled composites of ZrB2 and Al2O3 with same filled content, respectively. The predicted thermal conductive results of Al2O3 coated ZrB2 particles in epoxy matrix obtained by finite element analysis were in reasonable agreement with the experimental results.

Boride ceramics covalent functionalization and its effect on the thermal conductivity of epoxy composites

Zirconium diboride/aluminium oxide (ZrB2/Al2O3) composite particles were functionalized with epoxide functionalized γ-glycidoxypropyltrimethoxysilane by the covalent bonding approach to improve the interfacial compatibility of composite particles in epoxy matrix. The composites of epoxy resin filled with functionalized ZrB2/Al2O3 were prepared by in situ bulk condensation polymerization of bisphenol A and epichlorohydrin in the presence of ZrB2/Al2O3. The heat-conducting properties of composites were investigated by the finite element method (FEM) and the thermal conductivity test. The finite-element program ANSYS was used for this numerical analysis, and three-dimensional spheres-in-cube lattice array models were built to simulate the microstructure of composite materials for different filler contents. The thermal conductivity of composites was determined by laser flash method (LFA447 Nanoflash), using the measured heat capacity and thermal diffusivity, with separately entered density data. The results show that the effective chemical bonds are formed between ZrB2/Al2O3 and γ-glycidoxypropyltrimethoxysilane after the surface functionalization. The interfacial compatibility and bonding of modified particles with the epoxy matrix are improved. The thermal conductivities of functionalized composites with 3 vol% and 5 vol% loading are increased by 8.3% and 12.5% relative to the unmodified composites, respectively. Comparison of experimental values and calculated values of the thermal conductivity, the average relative differences are under 5%. The predictive values of thermal conductivity of epoxy composites are in reasonable agreement with the experimental values.

Preparation and characterization of epoxy/oregano oil as an epoxy-based coating material with both antimicrobial effect and increased toughness

The main objective of this work is to prepare an epoxy-based hybrid material with antimicrobial activity and increased toughness using a natural modifier. Therefore, oregano essential oil (OEO) was employed as a new additive for an epoxy thermosetting polymer. Mechanical properties of epoxy/OEO hybrids with different OEO contents were studied. Impact strength and fracture resistance of the hybrids were increased with increasing OEO content up to 15%. With the addition of 15% OEO to epoxy, maximum improvements of 69% and 83% were obtained for impact and fracture properties, respectively. Tensile properties of the hybrid decreased somewhat with increasing OEO content. Morphological properties of the epoxy/OEO hybrids were studied using scanning electron microscopy and Fourier transform infrared spectrometry. A dispersion of micron-sized OEO particles in epoxy matrix with relatively strong interactions between two phases in the interfacial area was observed as the main morphology. Antimicrobial activity of epoxy/OEO hybrids was examined using the disk diffusion method. The hybrid samples clearly showed antimicrobial activity against gram-positive and gram-negative bacteria. The hybrid had higher antimicrobial activity for fungus strain in comparison with bacterial strains.

Dynamic Mechanical Behaviour of Polymer Bonded Nd–Fe–B Composite Materials

Magnetic composite materials with varied content of Nd­Fe­B particles in epoxy matrix are examined from a dynamic mechanical perspective. Structural, viscoelastic and magnetic properties of composites have been observed using Scanning Electron Microscope (SEM), Dynamic Mechanical Analysis (DMA) and Super Quantum Interference Device (SQUID) magnetometer, respectively. Experimental results show that magnetic properties and corresponding dynamic mechanical behaviour depend on packing density. Also, results observed by predictive mathematical models suggest that maximal packing factor has a direct impact on elastic behaviour of composites. [doi:10.2320/matertrans.M2011218]

Propriedades mecânicas e termomecânicas de compósitos com partículas de diamante dispersas em matriz epoxídica modificada na razão resina/endurecedor

Foram estudadas as propriedades mecânicas dos compósitos com partículas dispersas de diamante em matriz de resina epóxi curada com diferentes proporções de endurecedor caracterizadas pela razão resina/endurecedor. Investigou-se também o comportamento termomecânico através de ensaios de DMA (Análise Dinâmico-Mecânica). No presente trabalho foi feita uma completa avaliação das propriedades mecânicas e termomecânicas no amplo intervalo de razão resina/endurecedor associado a possíveis aplicações tecnológicas. Foram fabricados compósitos com até 30% em peso de partículas de diamante dispersas em matriz epóxi do tipo DGEBA/TETA com diferentes razões resina/endurecedor, variando de 7 a 21. Para todas as condições investigadas a resistência diminuiu com a quantidade incorporada de diamante. Para matrizes com razão resina/endurecedor acima do estequiométrico 13, os compósitos apresentaram melhor desempenho mecânico. Os resultados dos ensaios termomecânicos mostraram que o módulo de armazenamento dos compósitos aumenta com a quantidade incorporada de diamante. Através da tangente delta foi possível avaliar prováveis mecanismos que contribuem para o desempenho termomecânico destes compósitos.