As the paper industry seeks to diversify fiber supplies and improve processing efficiency, agricultural residues and rapidly growing plants are attracting attention as potential alternatives to traditional wood resources. However, lower pulping energy requirements do not necessarily translate into suitable paper strength, particularly for containerboard applications where mechanical performance is essential.
A recent study published in Journal of Bioresources and Bioproducts examined the chemi-thermomechanical pulping (CTMP) of wheat straw, miscanthus, and bamboo. The researchers compared these materials with eucalyptus and three industrial reference pulps: unbleached softwood kraft, recycled old corrugated containers, and semi-chemical hardwood.
Using mild chemical pretreatment followed by mechanical refining, the researchers investigated fiberization energy, pulp yield, refining behavior, fiber morphology, and handsheet strength. The three non-wood feedstocks required 280–393 kWh per tonne for fiberization, compared with 538 kWh per tonne for eucalyptus, representing energy reductions of 27%–48%.
The mechanical testing revealed important differences among the alternative fibers. At a Canadian standard freeness of 500 mL, bamboo pulp achieved a burst index of 3.33 kPa m 2 g -1 , exceeding both unbleached softwood kraft (2.65 kPa m 2 g -1 ) and recycled corrugated container pulp (2.73 kPa m 2 g -1 ). Bamboo and wheat straw also achieved tensile indices of 40.4 and 36.4 N·m/g, respectively, surpassing semi-chemical hardwood pulp. Miscanthus, despite its relatively low fiberization energy requirement, showed weaker strength development.
Fiber morphology helped explain these differences. Bamboo exhibited narrow fibers, low coarseness, and a high slenderness ratio, characteristics associated with improved fiber-network formation. In contrast, the thicker, coarser fibers of miscanthus were less favorable for inter-fiber bonding.
The findings identify bamboo and wheat straw as promising complementary fiber sources for selected packaging applications. Nevertheless, the researchers emphasize that further optimization, pulp-blending studies, and pilot-scale validation are necessary to address processing conditions, contaminants, recyclability, and industrial integration before commercial implementation.
See the article:
DOI
https://doi.org/10.1016/j.jobab.2026.100320
Original Source URL
https://www.sciencedirect.com/science/article/pii/S2369969826000927
Journal
Journal of Bioresources and Bioproducts
Experimental study
Not applicable
Chemi-Thermomechanical Pulping of Wheat Straw, Miscanthus, and Bamboo: Fiberization Energy, Morphology, and Containerboard-Relevant Properties
27-Oct-2026