3D X-ray microtomography study on fibre breakage in noil hemp fibre reinforced polypropylene composites

X-ray microtomography, image processing and Weibull statistical methods were used to characterize the length and width distributions of noil hemp fibres before and after composite fabrication. X-ray microtomography provided direct observations and accurate measurements of length and width of noil hemp fibres within the hemp-polypropylene composite matrix. The effects of the weight content of the noil hemp fibre and the addition of compatibilizer on the fibre breakage and tensile strength of the composites were studied. The results indicated that the tensile strength of the noil hemp fibre reinforced composites without the coupling agent was lower than that of pure polypropylene. Fibre-fibre interaction mechanism indicated that high hemp content caused more fibre breakage. The addition of maleic anhydride grafted polypropylene (MAPP) coupling agent improved the tensile strength of the composites by the enhanced fibre/matrix interfacial adhesion. The addition of MAPP also reduced the fibre breakage due to the better dispersion of fibres.