Enhancement of mechanical properties on nano-filled hybrid composites

Publicações

Impact response of nano reinforced mat glass/epoxy laminates

Publication . Ferreira, J.A.M.; Santos, D.S.C.; Capela, C.; Costa, J.D.M.

The present work intends to characterize the effect that nanoclay and carbon nanotubes matrix reinforcements have on low velocity impact response of epoxy/glass fiber composites. The composite matrix used was the epoxy resin Biresin® CR120 combined with the hardener CH120-3 and the fiberglass triaxial mats ETXT 450. The results of the present paper are discussed in terms of load-time, load-displacement, energy-time diagrams and damage. The incorporation of nanoparticles produces only small improvement of the impact response in terms of the peak load and specific recovery energy. Peak load decreases slightly with increasing percentage of nanoparticles reaching a maximum decrease of 6 % for 3 wt% of nanoclays. Specific recovery energy increases in comparison with control formulation, around 14–18 % for 0.5 wt% addition of nanotubes and 7–15 % for 1 wt% of nanoclays, respectively. Specific recovery energy tends to decrease for higher percentages of nanoparticles in consequence of its poor distribution. Damaged area apparent shows a small reduction with nanoparticle content.

2015-03-04Artigo científico

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Mixed Mode interlayer fracture of glass fiber/nano-enhanced epoxy composites

Publication . Silva, H.; Ferreira, J. A. M.; Capela, C.; Richardson, M. O. W.

Increasing interlaminar fracture toughness (IFT) has long been an important goal in the fiber reinforced composites field. For that purpose some research has recently explored the use of nanoparticle reinforced matrices to improve interlaminar strength. In this present paper a small quantity of nanoclays (NC) and multiwalled carbon nanotubes (MWCNT) were used in order to enhance the IFT of glass fiber/epoxy composite laminates. The composites sheets were produced by a vacuum molding process. Mode I, Mode II, and Mixed-Mode I/II tests were performed to determine critical strain energy release rates, using double cantilever beam, end-notched flexure, and Mixed-Mode Bending specimens, respectively. Significant improvements in IFT were obtained for all loading modes by the incorporation of NC into the epoxy resin, whilst MWCNT produced only moderate improvements. For Mode I, IFT improvement by the incorporation of nanoparticle fillers, reached about 31% for 3 wt% of NC and 17% for 1 wt% of MWCNT. In Mode II the increase was about 50% for 3 wt% of NC and 30% for 1 wt% of MWCNT. The dispersion of small quantities NC and MWCNT into matrices significantly improved Mixed-Mode IFTs for all loading mode ratios G II/G. The total fracture toughness G increased under Mode II loading components and linear Mixed-Mode fracture criteria reproduced the Gc versus Mode ratios GII/G and GI versus GII relationship.

2014-05-27Recensão

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Palavras-chave

Nanocomposites,Nanoparticles,Mechanical behaviour,Finite elements analysis, Engineering and technology ,Engineering and technology/Materials engineering

Entidade financiadora

Fundação para a Ciência e a Tecnologia, I.P.

Programa de financiamento

Concurso para Projectos de I&D em todos os Domínios Científicos - 2009

Número da atribuição

PTDC/EME-PME/113695/2009