Effect Of Nanoclay On The Toughness Of Epoxy And Mechanical, Impact Properties Of E-glass-epoxy Composites

K. Krushnamurty1, I. Srikanth2, B. Rangababu2, S. K. Majee2, R. Bauri3, Ch. Subrahmanyam1*

1Department of Chemistry, Indian Institute of Technology (IIT) Hyderabad, Hyderabad 502205, India

2Defense Research and Development Organization (DRDO), ASL, Hyderabad 500058, India

3Department of Metallurgical and Materials Engineering, Indian Institute of Technology (IIT) Madras, 600036, Chennai, India 

Adv. Mater. Lett., 2015, 6 (8), pp 684-689

DOI: 10.5185/amlett.2015.5817

Publication Date (Web): Aug 02, 2015

E-mail: csubbu@iith.ac.in

Abstract


Organically modified montimorillonite nanoclay was added to the epoxy and E-glass-epoxy composites. The influence of nanoclay content (varied between 0 to 5wt %) on the relative crosslink density and the fracture toughness of the epoxy matrix was studied. Differential scanning calorimetry (DSC) indicated that the amino functional groups present on the nanoclay react with the epoxy matrix to increase the crosslink density of about 13 and 18% at 3 and 5wt% addition, respectively. The toughness of the epoxy composites increased by 25% at 3wt% addition of nanoclay, whereas, it decreases at 5wt%. Flexural strength and tensile strength of the E-glass-epoxy composites were found to increase by 12% and 11% respectively at 3wt% addition of nanoclay, while at 5wt% addition these properties decreased due to the matrix embrittlement.  Interestingly matrix embrittlement is found to be beneficial in increasing the impact resistance due to spallation of embrittled matrix that ensures the dissipation of the impact energy. 5wt% nanoclay addition increases the impact strength by 29% and reduces the back face bulge of composite by 31%. These results may lead to the design and realization of glass-epoxy composites with better impact strength.

Keywords

Nanoclay, glass fibers, fracture toughness, mechanical properties, differential scanning calorimetry.

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