The mean room-temperature values of the compressive true yield stress, σyc, compressive true fracture stress, σfc, and compressive true fracture strain, γf, are summarised in Table 2. The tensile yield stress is calculated from the measured compressive yield stress [39]. The addition of S-CSR particles reduces the compressive true yield stress, as expected, due to the relative softness of the polysiloxane rubber. The values decreased approximately linearly with increasing S-CSR particle content, see Fig. 4. At 20 °C, a value of 111 MPa was measured for the unmodified epoxy polymer, which also reveals that the unmodified epoxy should have the highest strength, if the effect of defects is excluded, when the test is conducted in uniaxial tension. The lowest value of the compressive true yield stress was measured to be 63 MPa for the 20 wt% S-CSR-modified epoxy polymer.
unmodified epoxy polymer
20 °C
°C
unmodified epoxy polymer
111 MPa
MPa
compressive true yield stress
lowest value
63 MPa
MPa
S-CSR-modified epoxy polymer
20 wt%
wt%