Influence of water absorptivity on kenaf fibre reinforced recycled-polymer composite properties

The hydrophilic nature of natural fibre in natural fibre composite (NFC) can reduce the material properties thus degrading the competitiveness of NFC as compared to synthetic fibre composite. This paper presents the water absorption effect on the mechanical properties of NFC made from kenaf reinforced recycled polymer blend. The recycled polymer blend is sourced from rejected-unused disposable diapers containing polypropylene and polyethylene (r-PP/PE). The kenaf flour fibre is compounded with r-PP/PE by using internal mixer machine with five variations of fibre loading which are 0, 30, 40, 50, and 60 wt.%. The water immersion test is conducted by immersing the samples in the distilled water for 24 hours as well as samples for tensile, flexural, and Izod impact tests. Experimental results show some improvement on some properties (impact strength) as well as degradation in other mechanical properties. The fractography analyses revealed the failure modes caused by fibre pull-out, matrix cracking, and fibre swelling and voids that induced micro cracks.