Thermal characterization of thermosets on the nanoscale
Sprache des Vortragstitels:
Euro AFM Forum
Sprache des Tagungstitel:
An important parameter to characterize epoxy resins is the glass transition temperature. While curing the epoxy resin is converted from liquid state to an insoluble glass state and a network of cross-linked polymer chains is formed. Above the gel point which indicates the transformation from rubber to glass, the glass transition temperature increases due to increasing molecular weight, branching and cross-linking density of the epoxy resin.
Our approach is to determine the glass transition point of epoxy resins with different curing stages using an AFM equipped with a heatable cantilever. Performing local thermal analysis is based on an appropriate temperature calibration with known polymer standards to correlate the tip temperature with the applied voltage on the tip. AFM has a high spatial resolution which allows the determination of local differences in the glass transition temperature.
The measured glass transition temperatures are correlated with the cross-linking density which was measured additionally with Raman spectroscopy. Monitoring of the cure process is often realized by spectroscopic methods. The data from Raman spectroscopy and local thermal analysis complement each other to get an overview of the cross-linking density of the epoxy resin.