Though potentially useful, agricultural byproducts are often discarded because of the lack of specific applications in many industries. However, they have suitable properties for use in the paper industry, according to recent literature. In this study, the suitability of rice husk, peanut husk, and garlic stem as raw materials for the manufacture of a new lignocellulosic bulking agent was investigated, and the best material to replace a commercial wood powder, widely used in Korean duplex board mills, was determined. Many powders were manufactured from agricultural byproducts, and their effects on the physical properties and drying energy requirements of handsheets were evaluated compared to those of a commercial wood powder. All of the powders improved the bulk and dryness after wet pressing, but a reduction in paper strength was unavoidable. In particular, the powder made from rice husk showed a greater bulk and increase in dryness after wet pressing than the commercial wood powder. These findings indicated that these three agricultural byproducts could be used as raw materials for the manufacture of bulking agents, and rice husk was the best agricultural byproduct to replace commercial wood powder in duplex board mills.

Wood powder is widely used in paperboard mills to increase bulk and reduce drying-energy consumption, but this material also deteriorates paper strength because it interferes with the bonds between fibers. Although there have been many studies done to improve the strength of paperboard containing wood powder, specific applications have not recently been observed in paperboard mills. In this study, we carried out a new approach for improving paperboard strength by developing a new organic filler with the ability to increase the bonds between fibers. The residue of tapioca starch was used as raw material to manufacture an organic filler. The functionalities, including bulk and strength, were evaluated by making handsheets containing either wood powder or tapioca organic filler, or a mixture of the two, and measuring their physical properties. The organic filler showed lower bulk improvement and higher paperboard strength than the wood powder. The mixture of tapioca organic filler and wood powder showed improved paperboard strength compared to wood powder alone. Therefore, tapioca residue can be used as a raw material to manufacture an organic filler for paperboard mills.