Effect of Variation in Urea Concentration Used in Retting, on the Chemical and Mechanical Properties of Kenaf Fibres

The overall aims of this study were to determine:

i. The effect of 1% and 2% urea solution on the α-cellulose, lignin and hemi cellulose content of kenaf fibre.
ii. The effect 1% and 2% urea solution on the tensile modulus and tensile strength of kenaf fibre.
iii. The effect 1% and 2% urea solution on the proximate compositions of kenaf fibre.

Study Design: Data obtained from each treatment were subjected to analysis of variance (ANOVA). Means were separated using Duncan multiple range test. Significant difference was accepted at P =.05.

Place and Duration: The retting experiment and laboratory analyses were carried out at the Institute of Agricultural Research and Training, Obafemi Awolowo University Ibadan, Nigeria. From April, 2015 to January, 2016.

Methodology: Two Kenaf stems were tied together as a replicate (with three replicates per treatment) and were soaked in improvised retting tanks containing 1% and 2% urea in 150litres of water and control (without urea). Fibres retted in 1%, 2% urea and control were subjected to proximate, chemical and mechanical assays. Microbiological and physico-chemical properties of the retting liquors were determined at two days interval.

Results: The urea treatment increased α-cellulose in kenaf fibres while the lignin content of Kenaf fibres was in the order: 2% urea > 1% urea > control. Two local varieties Ifeken DI 400 and Ifeken 400 recorded the least lignin. Hemi-cellulose content of Kenaf fibres from 1% urea was significantly lower than others. The highest protein and iron content were recorded in 2% urea followed by 1% urea and least in the control.

Conclusion: High enzyme activities in urea liquors ease the retting process and this had produced fibres with promising chemical and mechanical properties. Kenaf fibres retted in 2% urea had better tensile strength and higher α-cellulose content.