Methacrylate post-relaxation behavior

[Deravec]

Dear forum!

I would like to ask this question: does anyone here have an experience with mechanical behavior of methacrylate resins (or generally polymers) after undergoing stress relaxation?

After stress relaxation from a highly plastic stress value, what is the subsequent tangent E-modulus under both further loading and unloading? Does it remain quasi-plastic at lower stress level (further loading:weak , unloading:stiff), or does it recover to initial modulus (equal in both direction), or anything else (what)?

My work is computational, I need this particular information but cannot find it, and I try not have to make an experiment, which might exceed framework of my task...

Many thanks!

[Jorgen]

The unloading slope will typically be similar to the initial Young's modulus (i.e. stiff), and the tangent stiffness for further loading is typically smaller (and evolving to the even lower steady-state value).

-Jorgen

[Deravec]

Many thanks for the response! So was my intuitive idea, but would you, or someone else have a literature reference of this phenomenon?

[Deravec]

Would someone know a reference of this behavior (e.g. theory or experimental data)...? Or even a keyword "how is it called" would be sufficient, since nothing like "post-creep modulus or stiffness" can be found...

Many thanks!!!