Mechanical and curing behavior of tetra functional epoxy reinforced with nano fillers

Abstract

Synopsis Tetra-functional epoxy resins are used as a matrix for aerospace composites owing to their excellent mechanical, adhesive, corrosion resistance and thermal properties. Although epoxy is a high-performance thermosetting polymer, it is brittle due to its highly cross-linked network. This limitation must be addressed to make epoxy fit for aerospace applications. Plenty of potential filler materials such as organic and inorganic nano-particles, CNTs, two-dimensional nanomaterials such as graphene and its derivatives have been studied as reinforcing agents for epoxy composites. The high aspect ratio and active surface area of these nano-fillers contribute to the improved mechanical performance of the epoxy composites. Moreover, since these nano-fillers have active surface chemistry, it is essential to understand their effect on the epoxy-hardener curing reaction. Chapter 1 of this thesis briefly introduces the types and grades of epoxy resins and curing agents and the various stages of the curing reaction. The literature on the effect of nano-fillers on the curing behaviour of epoxy composites and the literature addressing the mechanical properties of epoxy composites for low loadings of nano-fillers was reviewed. It was found that studies on inorganic two-dimensional nano-fillers as toughening agents for epoxy composites are limited and have scope. Also, the curing behaviour of tetra-functional epoxy in the presence of nano-fillers is not very widely reported. Chapter 2 of the thesis lists all the materials, characterization methods and protocols used in this work. The models and equations used for the evaluation of curing kinetics have been explained in detail. The standard testing procedures used to calculate the mechanical properties of the epoxy composites have been explained in detail in this chapter. This thesis contains three works on the curing and mechanical behaviour of tetra-functional epoxy composites reinforced with nano-fillers. In the first work (chapter 3), ....