Use of biowax derived from Colocasia esculenta leaves for effective reduction in the hydrophilicity of Musa acuminata fibres for its potential application in cementitious composites

Banana fibre is regarded as a high strength sustainable material that is driven by the concept of waste valorisation. However, its water affinity is a serious inhibitor to the full-scale exploitation of this biomaterial in composites such as cementitious ones. Therefore, the aim of this study was to investigate the use of a biowax extracted from Colocasia Esculenta leaves as an ecological approach for surface coating of banana fibres. The coated fibres would then be used in concrete to cater for thermal insulation owing to the intrinsic low thermal conductivity of banana fibres. A novel experimental protocol was set up for the extraction which concerned fragmented and whole taro leaves at material to liquor ratio of 1:10 and 6.5 minutes immersion time. The extent of hydrophobicity of the biowax was reported by the least water uptake (2.3 ± 0.4%) of filter papers soaked in 0.007 g/mL biowax that was extracted from whole taro leaves. Subsequently, the banana fibres were characterised for their thermal conductivity (k-value) using the Modified Transient Plane Source sensor. The k-values of the plain and biowax coated fibres were reported at 0.048 and 0.052 W/m K respectively. From these findings, it was noted that the biowax coating on the fibre did not cause a significant decrease in the thermal insulation property of the fibre. Based on all these findings, biowax from C. esculenta leaves can be considered as a promising surface coating of natural fibres for protection against alkaline medium of cementitious composites.