I've just started a project on composites and for part of the project I will need to characterise and model the response of a thermoset epoxy resin under loading. The long-term goal is to characterise the resin at various strain rates and use the data in a micromechanical composites model.
Unfortunately my knowledge of polymers at this point is pretty limited and I'm trying to learn more about how the resin deforms and becomes damaged under load so here are some stupid newbie questions..
1) I've seen that thermoplastics are either semi-crystalline or amorphous, are thermosets always amorphous? How does the microstructure of the chains compare with thermoplastics?
2) What would I be able to observe by looking at a tensile test on an epoxy resin taking place inside the chamber of an SEM?
3) What kinds of physical phenomena are generally used to in physical constitutive models?
I want to use a physically based constitutive model rather than just a phenomenological model but my knowledge of the yield and failure sequences in the microstructure thermosets is extremely limited.
Any help/advice or recommended reading would be greatly appreciated.