| Kenaf (Hibiscus canabinus) is a promising non-wood plant fibre that can serve as a source fibre for pulping and papermaking. Because the chemical and physical composition of the plant changes as the plant develops, research is needed to determine its pulping properties at various stages of growth in order to establish the optimum harvesting time. In the present work, the chemical composition and pulping properties of kenaf as a function of growth have been studied. Kenaf plants were harvested at the end of 90, 120, 150, and 200 days (maturity). Extractive-free ground samples of the stem were cooked at three different temperatures of 140;The chemical analysis shows that the differences in holocellulose and lignin content for 90, 120, and 150-day old kenaf are not significant, while 200-day-old kenaf is significantly different from others. Micro-pulping properties of kenaf at various stages of growth are also not significant. However, statistically significant differences were observed in terms of physical properties of kenaf pulps. In comparing the fields of kenaf pulps, it is observed that the average yield for 150-day-old kenaf, over the whole range of cooking times and temperatures studied, is highest (60.4%) amongst the group. Kenaf can be harvested at the end of 150-day growth period, based on the results of chemical analyses to achieve higher yield, with reasonably lower lignin content. Since 90-day-old kenaf showed highest breaking length and stretch values, kenaf may also be harvested at the end of 90-day growth period, based on the physical properties of kenaf pulps. This may also allow to obtain 2-3 crops per year depending on the location. |
