Reinforcing Epoxy Polymer Composites Through Covalent Integration of Functionalized Nanotubes

Abstract

Strong interfacial bonding and homogenous dispersion have been found to be necessary conditions to take full advantage of the extraordinary properties of nanotubes for reinforcement of composites. We have developed a fully integrated nanotube composite material through the use of functionalized single‐walled carbon nanotubes (SWNTs). The functionalization was performed via the reaction of terminal diamines with alkylcarboxyl groups attached to the SWNTs in the course of a dicarboxylic acid acyl peroxide treatment. Nanotube‐reinforced epoxy polymer composites were prepared by dissolving the functionalized SWNTs in organic solvent followed by mixing with epoxy resin and curing agent. In this hybrid material system, nanotubes are covalently integrated into the epoxy matrix and become part of the crosslinked structure rather than just a separate component. Results demonstrated dramatic enhancement in the mechanical properties of an epoxy polymer material, for example, 30–70 % increase in ultimate strength and modulus with the addition of only small quantities (1–4 wt.‐%) of functionalized SWNTs. The nanotube‐reinforced epoxy composites also exhibited an increased strain to failure, which suggests higher toughness.

A review on the role of interface in mechanical, thermal, and electrical properties of polymer composites

“…The functional group of the fillers should react with an active group on the polymer chains of the host. One of the suitable methods for chemical bonds formation is the in situ polymerization, where the monomers react with each other and the fillers simultaneously [74][75][76][77][78]. The other way is to modify the host prior to the chemical attachement of the fillers [79].…”

Effects of silane functionalization on the properties of carbon nanotube/epoxy nanocomposites

“…In contrast, there was a stronger effect of silane-CNT in the rubbery region at elevated temperatures where the improvement in the elastic properties of nanocomposites was clearly observed wt%, however T g started to decrease because the epoxy/diamine ratio exceeded the value required by the reaction stoichiometry, which in turn decreased the degree of cross-linking in the nanocomposites [5,8]. Figure 6 shows the elastic moduli and strengths measured from the flexural test of nanocomposites, which are plotted as a function of CNT content.…”

Poly(3-hydroxybutyrate)/multi-walled carbon nanotubes nanocomposites: preparation and characterizations

“…Generally, the linkage of small or large molecules to the CNTs by covalent methods is more stable and effective than the noncovalent ones. So, the covalent methods, by which carboxylic acid groups formed at the ends and the defect sites of CNTs, were commonly used for the precursor functionalization in the formation of ester, and organometallic structures [25,26].…”