Evaluation of pulp and paper making characteristics of elephant grass (Pennisetum purpureum Schum) and switchgrass (Panicum virgatum L.)

Abstract

Shortage of conventional raw material for the pulp and paper products together with the increasing world demand for paper has renewed interest in non-wood fibres. Non-wood pulping capacity has been increasing steadily over the last decade. A lot of crops grown for biomass, like switchgrass (Panicum virgatum L.), are good examples of plants with potential for pulp production. Raw material chemical composition, kraft pulp yield and properties, and fibre characteristics of elephant grass or hybrid pennisetum (Pennisetum purpureum Schum. cv. SDPN3) and switchgrass (cv. Cave-in-Rock) were determined in an effort to evaluate them as raw materials for pulp and paper production. Elephant grass had α-cellulose and Klasson lignin contents of 45.6 and 17.7%, respectively. The respective values for switchgrass were 41.2 and 23.89 %. Pulp yields, following a mild kraft process, were 48 and 50% for switchgrass and elephant grass, respectively. The corresponding kappa numbers were 15.5 and 9.2. The weight-weighted fibre length averaged 1.32 mm. Pulp freeness was higher for switchgrass (330 mL) than for elephant grass (139 mL). Elephant grass had a burst index above 5.85 kP.m² g^-1. These characteristics demonstrate the suitability of both elephant grass and switchgrass for pulp production.

Key words: Grass pulp, kraft pulping, non-wood fibre, elephant grass, switchgrass.