Differential Scanning Calorimetry study on curing kinetics of diglycidyl ether of bisphenol A with amine curing agents for self-healing systems

Gustavo Cervi,Sérgio Henrique Pezzin,Marcia Margarete Meier

doi:10.1590/s1517-707620170002.0183

Gustavo Cervi, Sérgio Henrique Pezzin + Show 1 more

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https://doi.org/10.1590/s1517-707620170002.0183

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Abstract

ABSTRACT Epoxy resin is one of the most important polymeric matrixes for diverse uses, such as aeronautical, mobile, electronics and others. Providing a material capable of self-healing microcracks will allow it to have a more reliable and longer use. In order to study this new property of self-healing to an epoxy resin, a Differential Scanning Calorimetry (DSC) study was carried out to measure physical chemical properties such as activation energy, enthalpy of polymerization, order of reaction and pre-exponential factor based on an Arrhenius equation modelling. The materials used are diglycidyl ether of bisphenol A (DGBA) as the core material, triethylenetetramine (TETA) and an aminated polydimethylsiloxane (ADM), as curing agent and poly(urea-formaldehyde) (PUF) as microcapsule wall. Tests were done by dynamic and isothermal DSC of systems containing the resin and microencapsulated curing agent and also the resin with the free curing agent. The results showed the necessity of heating for the cure and the self-healing to be initiated.

Highlights

The use of polymers and composite materials has been increased in structural engineering applications
This paper shows a kinetic and calorimetric study by Differential Scanning Calorimetry (DSC) of the cure process of the resin bisphenol A diglycidyl ether (DGEBA) (Fig. 1) with two crosslinking agents potentially useful for self-healing composites - triethylenetetramine (Fig. 2) and an aminated polydimethylsiloxane (Fig. 3) - in order to evaluate the curing behaviors at different temperatures
It is clearly seen that the cure of diglycidyl ether of bisphenol A (DGEBA)/aminated polydimethylsiloxane (ADM) systems occurs at higher temperatures, presenting a much higher activation energy and exponential factor

Summary

Introduction

The use of polymers and composite materials has been increased in structural engineering applications. These materials are exposed to mechanical and thermal fatigue as well as UV radiation, chemical and environmental change which can lead to the formation of microcracks. These microcracks are difficult to detect and repair, compromising its use along time and possibly causing accidents. Self-healing polymers containing microcapsules filled with an agent of regeneration, usually monomers and / or primers, dispersed in the polymer matrix. If eventually a crack is generated in the material, this will find the microcapsule that will be broken, releasing the regeneration agent into the crack, which, in turn, will polymerize preventing crack propagation [3,4,5]

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