Enhancement of mechanical properties of aluminium/epoxy composites with silane functionalization of aluminium powder

doi:10.1016/j.compositesb.2011.12.010

Composites Part B: Engineering

Volume 43, Issue 4, June 2012, Pages 1743-1748

https://doi.org/10.1016/j.compositesb.2011.12.010 Get rights and content

Abstract

In this study, the effect of surface modification of aluminum powders on the tensile, fracture, and tribological behaviors of aluminum/epoxy composites was investigated. Aluminum powders were surface-modified with 3-aminopropyltriethoxysilane. Aluminium/epoxy composites were fabricated by cast molding method using 10 wt.% untreated and silane-treated aluminium powders. Tensile, mode I fracture, and tribological tests were performed on both composites. The results showed that the tensile modulus and strength of silane-treated aluminum/epoxy composites were ∼9% and ∼12% greater, respectively than those of untreated aluminum/epoxy composites. The results also showed that the fracture toughness and wear resistance of silane-treated aluminum/epoxy composites were ∼32% and ∼56% greater than that of untreated aluminum/epoxy composites. Scanning electron microscope (SEM) examination showed the improvement of tensile and fracture properties of silane-treated aluminum/epoxy composites was attributed to the improved dispersion and bonding of aluminum particles in the epoxy, due to the silanization of aluminium powders.

Introduction

Aluminum/polymer composites are attractive materials for a wide range of industrial applications due to the combination of properties such as low density, corrosion resistance, thermal stability, and ease of fabrication. Accordingly, many studies have been made to investigate the mechanical, thermal, and electrical properties of aluminum powder reinforced polymer composites [1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11]. One of the main issues in the fabrication of aluminum/polymer composites is to achieve the good dispersion and interfacial strength between aluminium powders and the polymer. To address this issue, some studies have been performed for the surface treatment of aluminum powders. Jallo et al. [12] reported the effect of surface modification on aluminium powder on its flowability, combustion and reactivity. Silanization provides lower surface energy values and such materials are expected to flow better after surface treatment. Chen et al. [13] investigated modification of aluminium powders applying methyltrichlorosilane. The basic procedure involved mixing of aluminium powder with silane solution in hexane. Crouse et al. [14] demonstrated functionalization of oxide-passivated aluminium nanoparticles using 3-methacryloxypropyltrimethosilane (MPS) to provide chemical compatibility within various solvent and polymeric systems. However, not much work has been made to investigate the surface modification of aluminum powder to improve fracture and tribological properties of aluminum reinforced epoxy composites.

In this study, the effect of silane treatment of aluminum powders on the tensile, fracture, and tribological behaviors of aluminum/epoxy composites was investigated. Aluminium/epoxy composites were fabricated by cast molding method using 10 wt.% unmodified and silanized aluminium powders. FTIR analysis was made on the untreated and silanized aluminium powders to determine the chemical change on the surface of aluminum powders due to the silane treatment. Tensile, mode I fracture, tribological tests were performed on both composites. After fracture and tribological tests, scanning electron microscopy (SEM) examination was made to determine fracture and wear mechanisms of aluminum/epoxy composites, depending on the silane treatment of aluminum powders.

Section snippets

Materials

The reinforcing material used in this study was aluminium powders of ∼45 μm size (Strem Chemicals, USA). The epoxy used was diglycidil ether or Bisphenol A (YD-115, Kukdo Chemical, Korea), and the curing agent was polyamidoamine (G-A0533, Kukdo Chemicals, Korea). 3-Aminopropyiltriethoxysilane with a purity of 99% (Aldrich, USA) was used as a silane functionalization agent.

Silanization of aluminium powders

60 g of unmodified aluminium powders were dispersed in 250 ml of ethanol via mechanical stirring for 30 min. Then the reaction

Results and discussion

FTIR spectral analysis was made to determine the chemical change on the surface of aluminum powder due to the silane treatment. Fig. 1 shows the FTIR spectra of untreated and silane-treated aluminium powders. For untreated aluminium powder, the peaks at 3440 cm⁻¹ (Fig. 1a) and 1048 cm⁻¹ (Fig. 1b) were caused by hydroxyl groups (Al–OH) on the surface of aluminium powder due to the presence of atmospheric moisture on the surface of aluminum powder. For the silane-treated aluminum powder, the

Conclusions

This study demonstrated the enhanced mechanical properties of aluminium/epoxy composites by silane treatment of aluminium powders. The conclusions obtained from this study are as follows: First, the tensile modulus and strength of aluminum/epoxy composites are improved ∼9% and ∼12% by the silane treatment of aluminum powders. Second, the fracture toughness and wear resistance of aluminum/epoxy composites are also improved ∼32% and ∼56% with silane treatment of aluminum powders. Third, the wear

Acknowledgements

This work was financially supported by the National R&D Project of “Development of Energy Utilization of Deep Ocean Water” supported by the Korean Ministry of Land, Traffic and Maritime Affairs.

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Enhancement of mechanical properties of aluminium/epoxy composites with silane functionalization of aluminium powder

Abstract

Introduction

Section snippets

Materials

Silanization of aluminium powders

Results and discussion

Conclusions

Acknowledgements

Electrochim Acta

J Power Sources

Powder Technol

Surf Coat Technol

Composites: Part A

J Alloys Compd

J Mater Process Technol

Composites: Part B