Tailoring sustainable compounds using eggshell membrane as biobased epoxy catalyst

Abstract

In this work eggshell membrane was added as biobased curing catalyst to epoxy (DGEBA), for comparison purposes the synthetic catalyst DEH 35 data was reported, the curing of compounds was followed through differential scanning calorimetry (DSC) under dynamic conditions and their kinetics were modeled using Kissinger, Friedman, Friedman model based and Málek approaches. From evaluated E_a and $lnA$ two steps of curing were verified, for the synthetic catalyst compound (S₅) E_a abruptly increased for the degree of conversion $\alpha >0.7$ the opposite trend was observed for the eggshell membrane compound (M₁₀). It is supposed for S₅ E_a increases due to the competitive reactions leading to viscosity increase until reach the solid phase with decrease of the reactive groups availability, hampering the cross-linking, whereas for M₁₀ E_a decreases at $\alpha >0.7$, hence invalidating the Kissinger model which assumes constant E_a.

Keywords:
curing; eggshell membrane; epoxy; kinetics