Evaluation of Grevillea robusta as a raw material for the production of dissolving pulp and viscose rayon

Grevillea robusta, onchertrical analysis, showed very high pentosan content (19.9%), average extractives (5.35%) and low lignin (22.39%) and inorganic (0.76%) contents. Prehydrolysis followed by kraft cooking was carried out by varying the prehydrolysis and cooking conditions to obtain the desired characteristics of unbleached pulp, i.e. low permanganate number (5.2-7.4), low pentosan (2.47-2.92%) and low viscosity (24.65-38.82 cP). The unb,eached pulp was bleached using C -E -H -D -C.C -SO2 sequence under controlled conditions. Ble.,ched pulps with brightness of87 .6-91.3% (EL) were obtained on bleaching. The bleached pulps contained 95.4-96.52% cx-cellulose, 0.06% inorganic matter and the copper number of pulps W1lsin the range of 0.39-0, 50. The bleached pulp was evaluated for the production of dissolving-grade pulp by measuring the filterability of viscose made out of it. The filterability value of viscose was 227 KWc, which conforms to the required dissolving pulp characteristics. The fibre spun from viscose on the standard prototype spinning ma,chine was tested for strength characteristics and found comparable to the commer~ial rayon fibres.