Assessing bleached bamboo fibers as a hardwood replacement via kraft co-cooking for paperboard applications

The increasing demand for sustainable packaging worldwide, coupled with rising hardwood costs in the southern United States, has driven interest in alternative raw materials for the pulp and paper industry. Bamboo ( Phyllostachys nigra “Henon” ) presents a promising substitute due to its rapid growth, fiber characteristics, and suitability for kraft pulping. This study investigates the kraft co-cooking of bamboo and hardwood as a strategy to optimize fiber sourcing for Solid Bleached Sulfate (SBS) applications. Pulping, bleaching, and refining experiments were conducted to evaluate the performance of bamboo-hardwood blends compared to single-species pulps. Results indicate that bamboo delignification is faster than hardwood but exhibits lower pulping yield (45.8 % vs. 50.5 %). Co-cooked pulps retained favorable fiber morphology and mechanical properties, enhancing the tensile and tear strength of bamboo and hardwood-bamboo mixtures when refined at similar Canadian Standard Freeness values. The D₀EopD₁ bleaching sequence achieved comparable brightness (approx. 90 % ISO) for all pulps, while bamboo and co-cooked hardwood-bamboo pulps exhibited higher viscosity than hardwood pulp. Calendering produced similar smoothness across all pulps. These findings suggest that kraft co-cooking offers a viable approach to integrating bamboo into SBS paperboard production, mitigating hardwood supply constraints while maintaining high-quality pulp characteristics. • Bamboo and hardwood co-cooked under kraft conditions; D0-Eop-D1 bleaching achieves high brightness. • Co-cooked bamboo-hardwood pulps offer high tensile and tear strength, with enhanced smoothness via calendering. • Kraft co-cooking of bamboo and hardwood supports hardwood replacement in paperboard manufacturing.