Chemical and soda pulping properties of kenaf as a function of growth

Kenaf (Hibiscus canabinus) is a promising non-wood source of fibre for pulp ing and papermaking. Because the chemical and physical composition of the p lant changes as the plant develops, research is needed to determine its pul ping properties at various stages of growth in order to establish the optim um harvesting time. In the present work, the chemical composition and pulpi ng properties of kenaf as a function of growth have been studied. Kenaf pla nts were harvested at the end of 90, 120, 150, and 200 days (maturity). Ext ractive-free ground samples of the stem were cooked at three different temp eratures, 140, 155, and 170 degreesC, using soda cooking liquor of 32 g/L N aOH, with an active alkali charge of 15% as Na2O, and a liquor-to-wood rati o of 6:1. The differences in the holocellulose and lignin content for 90, 1 20, and 150-day old kenaf were not significant, while 200-day-old kenaf was significantly different from others. Pulping of kenaf at various stages of growth indicated that soda pulping properties were not significant. In com paring the yields of kenaf pulps, it is observed that; over the whole range of cooking times and temperatures studied, the average yield for 150-day-o ld kenaf is highest at 60.4%. Kenaf can be harvested at the end of 150-day growth period, based on the results of chemical analyses to achieve higher yield, with lower lignin content.