Approaches on the non-isothermal curing kinetics of epoxy/PCL blends

Abstract

The non-isothermal curing kinetics of DGEBA/PCL/MTHPA/DEH 35 blends at 10, 20 and 30 phr of PCL were investigated applying Ozawa, Kissinger, Friedman autocatalytic, Friedman isoconversional and Málek models. From verified discrepancies between theoretical and experimental fits measured based on the models parameters such as activation energy (Ea) and molecular collisions frequency (ln A), Ozawa and Kissinger presented higher deviation most likely due to the considered invariable energy along with the curing, while in Friedman and Málek's perspectives it is changeable, hence providing better data adjustments. PCL led to lower collision frequency among molecules, suggesting lower density microstructure related to epoxy, which corroborates to the system composed by physical (hydrogen bonds) and chemical (covalent bonds) crosslinking, altogether might provide swollen coils and occasionally, an interconnected structure that percolates the system resulting in (macro) gelation instead reticulation affording the workable character on epoxy/PCL blends.

Keywords

• DGEBA
• PCL
• Ozawa
• Kissinger
• Friedman
• Málek