3. Results and discussion
3.1. Tensile property of single fibers Fig. 1(B) shows the stress–strain curve of a representative single fiber sample. The stress and strain have a linear relation. The
tensile modulus of 15.2 ± 3.24 GPa was within the range, namely
9.4–22.0 GPa, reported by Bledzki and Gassan [3]. The elongation at break of 3.0 ± 0.37% was slightly larger than the value of 2.0–2.5% reported in [3]. The measured tensile strength showed largervariability, namely 394.2 ± 110 MPa, which was below the range of 511–635 MPa reported in [3]. As will be shown in the following,
the tensile properties of the composites generally fell in between
those of the sisal fibers and the PE matrix. The incorporation of stiffer sisal fibers into the more compliant matrix enhanced the tensile
modulus and strength of the matrix, while reducing the elongation
at break of the matrix.