Epoxy/Silica Nanocomposites: Nanoparticle‐Induced Cure Kinetics and Microstructure

Abstract

This study reveals the influence of silica nanoparticles on the cure reactions of a diglycidyl ether of bisphenol A epoxy resin. As soon as the silica nanoparticles are added to the neat resin (1, 3, and 5 vol.‐%), the total degree of conversion increases with an increasing amount of nanoparticles, and the cure reaction shows a more complex autocatalytic behaviour, which can not be described by a traditional kinetic model. Results from subsequent thermo‐mechanical analyses confirm an alteration in the microstructure attributable only to the presence of the nanoparticles in the curing stage. An amino‐rich interphase around the reactive treated particles is formed, which shifts the resin/hardener ratio, and benefits the homopolymerization of the epoxy and leads to a more highly crosslinked epoxy network. At the same time, the nanophase consists of a core‐shell structure with the rigid particle inside and a rubber‐like shell because of the excess hardener in this region.TEM image of two neighboring silica nanoparticles in the epoxy matrix showing a 2–3 nm altered interphase region.magnified imageTEM image of two neighboring silica nanoparticles in the epoxy matrix showing a 2–3 nm altered interphase region.

Epoxy resin composites with surface‐modified silicon dioxide nanoparticles: A review

“…9 The addition of 1-5 vol % nanosilica led to a higher reactivity in curing and an alteration in crosslinking. They suggested the formation of an amino-rich interphase region around the silica nanoparticles, which could have been responsible for the property improvements.…”

Viscoelastic Properties of Amine-Cured Epoxy-Titania Composites Obtained by the Sol-Gel Method

“…For the synthesized epoxy-titania composites the T g values decrease with the filler content increase may be caused by possible non-complete removal of butanol (the TBT hydrolysis product), which may adsorb on the titania surface, and its plasticizing effect, as well as the possibility of the amine hardener selective adsorption on the high-energy filler surface [18]. In the latter case, nonreacted epoxy resin acts as a plasticizer, which leads to the polymeric network topology disruption compared to the pure epoxy polymer.…”

Interphases, gelation, vitrification, porous glasses and the generalized Cauchy relation: epoxy/silica nanocomposites

“…Great efforts have been made to provide relationships between the desired mechanical properties and the morphology of the nanocomposites [23]- [27]. Among others, scanning electron microscopy, transmission electron microscopy and atomic force microscopy have been used as investigation techniques for elucidating the local structure of these composites including interphases [27].…”