I have seen that in CNT -polymer composites the bonding strength (van der waals, covalent etc) has been predicted by simulation. Is there any method to experimentally measure bonding strength or some other parameter.
Your composite has few carbon tubes. Therefore, it is important to see how they are embedded in the composite. Use Raman spectroscopy for these purposes. See how the measurement results are processed.
There would be the possibility to perform tensile tests applying a pico-indenter mounted inside a REM. A saw some presentations about tests on whiskers and found a descripition for testing whiskers/nanowires: https://www.hysitron.com/media/1526/mem09an-r1f.pdf
If you fix the polymer and attach the pico-indenters tip to a nanotube (that is bonded to the polymer) you can investigate the bonding strenght by pulling the nanotube.