Reversible Self-Healing Carbon-Based Nanocomposites for Structural Applications.

Liberata Guadagno,Giuseppina Barra,Wolfgang H Binder,Carlo Naddeo,Andrea Sorrentino,Marialuigia Raimondo,Elisa Calabrese,Sravendra Rana,Luigi Vertuccio,Philipp Michael

doi:10.3390/polym11050903

Abstract

Reversible Hydrogen Bonds (RHB) have been explored to confer self-healing function to multifunctional nanocomposites. This study has been carried out through a sequence of different steps. Hydrogen bonding moieties, with the intrinsic ability to simultaneously perform the functions of both hydrogen donors and acceptors, have been covalently attached to the walls of carbon nanotubes. The epoxy matrix has been modified to adapt the formulation for hosting self-healing mechanisms. It has been toughened with different percentages of rubber phase covalently linked to the epoxy precursor. The most performant matrix, from the mechanical point of view, has been chosen for the incorporation of MWCNTs. Self-healing performance and electrical conductivities have been studied. The comparison of data related to the properties of nanocomposites containing incorporated functionalized and nonfunctionalized MWCNTs has been performed. The values of the electrical conductivity of the self-healing nanocomposites, containing 2.0% by weight of functionalized multiwalled carbon nanotubes (MWCNTs), range between 6.76 × 10−3 S/m and 3.77 × 10−2 S/m, depending on the nature of the functional group. Curing degrees, glass transition temperatures, and storage moduli of the formulated multifunctional nanocomposites prove their potential for application as functional structural materials.

Highlights

The concept of materials having the ability to repair themselves is mainly inspired by nature.In living systems, damages which do not completely compromise the structural entity of the system or part of it are able to activate spontaneous healing mechanisms
We have evaluated the increase of hydrogen bonds due to functional groups with respect to those due to the structure of the hosting epoxy matrix
Electrically conductive self-healing resins based on Reversible Hydrogen Bonds (RHB) interactions have been with a content of functionalized multiwalled carbon nanotubes (MWCNTs) of 0.5%, the values of glass transition temperature are lower: 182 ◦ C for TCTBD + 0.5%MWCNT-t and 175 ◦ C TCTBD + 0.5% MWCNT-b

Summary

Introduction

The concept of materials having the ability to repair themselves is mainly inspired by nature. Damages which do not completely compromise the structural entity of the system or part of it are able to activate spontaneous healing mechanisms. The big challenge to transfer this ability to structural synthetic materials lies in the fact that these materials, unlike living systems, have no metabolic activity. Even in inanimate matter, nature provides effective insights to achieve this goal. The imitation of natural mechanisms opens emerging and fascinating perspectives.

Methods

Results

Conclusion