PSI - Issue 10

A. Sanida et al. / Procedia Structural Integrity 10 (2018) 257–263

258

A. Sanida et al. / Structural Integrity Procedia 00 (2018) 000 – 000

2

Nomenclature DMA

Dynamic Mechanical Analysis

E ՛ Ε″

storage modulus loss modulus

phr

parts per hundred resin per weight Scanning Electron Microscopy

SEM

T

temperature

as ZnFe 2 O 4 , and Fe 3 O 4 ferrites. c. Hard ferrites with the magnetoplumbite (hexagonal) structure such as Ba and Sr hexaferrites. Due to their good magnetic and electrical properties, ferrites are used predominately in three areas of electronics: low level applications, power applications, and Electro-Magnetic Interference (EMI) suppression (Pullar (2012)). The breadth of application of ferrites in electronic circuitry continues to grow. The wide range of possible geometries, the continuing improvements in material characteristics and their relative cost-effectiveness make ferrite components the choice for both conventional and innovative applications (Scarlatache et al. (2012) ; Özgür et al. (2009)). There is a growing demand for multifunctional composites to meet special requirements of electronic components (Ramajo et al. (2009)). A probable drawback of these devices could be not their electromagnetic behavior but their thermomechanical stability, which is the exact purpose of this study. In the present study, series of nanocomposite systems consisting an epoxy resin as matrix and five different magnetic oxides nanoparticles (YIG, ZnFe 2 O 4 , Fe 3 O 4 , BaFe 12 O 19 and SrFe 12 O 19 ) as reinforcing phase, have been prepared and studied, varying the filler content. Specimens ’ m orphology was assessed via Scanning Electron Microscopy (SEM). The thermomechanical characterization was conducted via Dynamic Mechanical Analysis (DMA) and static tensile tests. Five-different ferrite/epoxy systems were prepared with the same method, by employing commercially available materials. Epoxy resin and curing agent with trade names Epoxol 2004A and Epoxol 2004B, (both provided by Neotex S.A., Athens, Greece), and the magnetic iron oxide nanoparticles (YIG, ZnFe 2 O 4 , Fe 3 O 4 , BaFe 12 O 19 and SrFe 12 O 19 ) (Sigma Aldrich), were used for the preparation of the composite systems. The particle diameter of nano powders, as denoted by the supplier, was less than 100 nm. The preparation procedure involved mixing of the resin with the curing agent in a 2:1 (w/w) ratio and then adding various amounts of the nanoparticles. Filler’s con tent was 1, 3, 5, 10, 15 20 phr (parts per hundred resin per mass). The mixture was stirred at a slow rate in a sonicator for 10 minutes. Subsequently, the mixture was poured into silicon molds and cured at ambient for 7 days. The post curing took place for 4 hours at 100 o C. The morphology of the produced specimens was checked for the presence of clusters, while the quality of the filler dispersion within the polymer matrix was examined via SEM (EVO MA 10, ZEISS). The thermomechanical investigation was conducted by Dynamic Mechanical Analysis (DMA) in the temperature range from room temperature to 100 o C with 5 o C/min heating rate, using TA Q800 device, provided by TA Instruments. Additionally, the mechanical properties of nanocomposites were examined with static tensile tests using an Instron 5582 apparatus provided by Instron, at room temperature with 5 mm/min tension rate. 2. Experimental protocol

3. Results and discussion

3.1. Morphological characterization

The quality of the specimens was examined via SEM. Representative images are shown in Fig.1 for three of the examined systems. The nanoparticles dispersion can be considered as successful, since fine nanodispersions can be detected and the formation of large aggregates has been avoided, moreover in all specimens limited or even no agglomeration is present.