Study of the interfacial properties of natural fibre reinforced polyethylene

In the present paper, the interfacial properties of extruded and compression moulded natural fibre reinforced thermoplastics (NFRTP) are studied. The interfacial shear strength of PE-sisal composites was measured using the single fibre fragmentation test (SFFT). The difficulties in obtaining significant measurements are discussed and assessed. The main problems found were the non-transparent nature of the matrix, the irregular shape of the fibres, and the variability in fibre-matrix adhesion encountered even in single fibre specimens. Scanning Electron Microscope (SEM) pictures obtained from fractured surfaces were used for a qualitative evaluation of the interfacial properties of NFRTPs. Fibre treatment with stearic acid increased the interfacial shear strength by 23% with respect to untreated fibres. The improvements in interfacial shear strength found for the treated specimens were consistent with observations from SEM fractographs.