Issue 72

N. Naboulsi et alii, Fracture and Structural Integrity, 72 (2025) 247-262; DOI: 10.3221/IGF-ESIS.72.18

alignment of polymer chains under stress becomes limited, which increases the material's strength and reinforces its fracture toughness. In contrast, at lower speeds, the material has more time to restructure its polymer chains, leading to increased ductility and have a progressive transition to fracture. This is due to the presence of Carbon Black, which increases PLA's rigidity and reduces its capacity for deformation thanks to its conductive fillers that limit the mobility of polymer chains. As a result, the PLA-CB fails at a higher stress level with less deformation under rapid loading conditions.

a)

x88

Pore

x88

Pore

b)

x88

x200

c)

Figure 8: SEM images of the fracture surface after tensile testing (scale bar is 500 µm). a) With 0° orientation at 88x magnification. b) With 45° orientation at 88x and 200x magnification. c) Mapping the distribution of C and O elements in a sample.

254