The proportionality constants in Fig. are rather different from the theoretically predicted value of 10 in Eq. 2, but the linear correlations between EIT and HIT hold quite well within given polymer system. In our case, we have two separate systems: PLA composites (Fig. ; blue color, proportionality constant = 59) and PCL composites (Fig. ; orange color, proportionality constant = 17). The last correlation in Fig. confirmed the direct proportionality between microscale indentation modulus, EIT, and macroscale tensile modulus, E, in agreement with O&P theory . The macromechanical properties are described in more detail in the next section, but the fact that macro-and micromechanical properties exhibited a good correlation was an important confirmation of the reliability and reproducibility of our characterization methods.