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Toughness and roughness in hybrid nanocomposites of an epoxy matrix
Author(s) -
Schuster Marcia B.,
Coelho Luiz A.F.
Publication year - 2019
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.25109
Subject(s) - materials science , nanocomposite , epoxy , composite material , carbon nanotube , fracture toughness , surface roughness , graphene , exfoliation joint , composite number , toughness , nanoparticle , surface finish , nanotechnology
The present paper investigates the relationship between roughness and toughening mechanisms in hybrid epoxy nanocomposites with carbon nanotubes (CNT) and graphene nanoplatelets (GNPs). The role of adding a block copolymer (BC) to the studied systems was also investigated. The nanocomposites were prepared by means of high‐energy sonication and in situ polymerization. All nanocomposites presented higher numerical values for K Ic than untoughened systems. The system containing 0.5 wt% of CNTs presented an increase of 35% in K Ic compared to neat epoxy, and the hybrid nanocomposite, at the proportion of 1:1 (CNT:GNP), with 0.5 wt% total of nanoparticles and also containing 0.5 wt% of BC, had an increase of 34% compared to the neat epoxy. Systems with higher amounts of graphene showed the highest roughness values, having crack deflection/exfoliation between the GNP layers as the main toughening mechanism. On the other hand, systems with more CNTs presented a lower fracture surface roughness, and the main toughening mechanism was bridging/break‐up of the nanotubes. Hybrid systems have more types of mechanisms than simple ones. With only one type of nanoparticle, however, some of those mechanisms are not effective in increasing the toughness, only increasing the fracture surface roughness. POLYM. ENG. SCI., 59:1258–1269 2019. © 2019 Society of Plastics Engineers