I prepared polymer blend of low and ultra high molecular weight Polyolefins. I need to know which techniques should I use to know if this polymer blends are stable over time and no phase separation will be happened over time. Is there any test may be high temperature aging or other accelerated test that I can conduct to see if there is any phase separation happens or they are stable over time. Also, which characterization method will be useful to characterize the phase separation of blends.

Thanks for your suggestions