Typical tensile stress-strain curves for flax/PLA and flax-paper/ PLA are displayed in Fig. 6. For each test, two linear portions are observed in the curves, one at the start of the test (approximately between 0 and 0.075% of strain) and another one between 0.4% up to the end. Two different moduli have been measured based on these two linear portions, the initial modulus (Ei) and the modulus (E). They have been calculated separately as suggested by previous authors by taking the slope of r-e curve between 0 and 0.075% for Ei and between 0.4% up to the end of curve for E [8,25].