CHEMICAL CHARACTERISTICS AND KRAFT PULPING RESPONSE OF PHYLLOSTACHYS PUBESCENS STEM, RECYCELED BAMBOO AND E. GRANDIS WOOD

Bamboo has been reported to be a raw material at some kraft pulp mills. However, there are few findings on the relationship between the chemical conditions and their responses to cooking and bleaching. In this study, Phyllostachys pubescens obtained from Ibaraki prefecture of Japan, and bamboo scrap (recycled bamboo) obtained from Hangzhou, China, were chemically analyzed, cooked by Kraft method, and bleached with totally chlorine-free (TCF) bleaching. Results showed that while the lignin content of the recycled bamboo was the highest, it was similar for the P. pubescens stem and the E. grandis wood, and xylan content of P. pubescens is higher than that of the E. grandis wood, with that of the recycled bamboo in-between. In obtaining pulps with given kappa numbers, the delignification response of P pubescens was equal to that of E. grandis and better than that of recycled bamboo. The hexenuronic acid contents of P. pubescens and recycled bamboo kraft pulp were lower than that of E. grandis. The brightness values of the unbleached as well as oxygen delignified pulps prepared from p. pubescens and recycled bamboo were much higher than that from E. gradis. However, the E. gradis pulp showed much better brightness development in AZEP bleaching. Nevertheless, the recycled bamboo pulp had the similar brightness development both in the cooking, oxygen delignification, as well as the AZEP bleaching, indicating that recycled bamboo is also a good raw material for making bleached kraft pulp.