Comparative Study on the Physical Properties of Edgeworthia and Wikstroemia Handmade Paper

Both Edgeworthia and Wikstroemia have been used traditionally in hand papermaking in China. As plants from the Thymelaeaceae family, these species have been mentioned periodically and have been mixed or substituted with each other. This study reviewed their papermaking background and status, and selected one of the Edgeworthia and three of the Wikstroemia raw materials that are still in use. Pulp was cooked under the same conditions in the laboratory, and handsheets of pure and mixed materials were obtained using a Rapid-Köthen sheet former. A series of physical properties, such as color, structure, and mechanical properties were tested, followed by a comparison and discussion of the raw material properties. The results show that Wikstroemia fibers are generally thinner and shorter, but there are variations between the different genera of raw materials. Thus, compared with Edgeworthia, Wikstroemia has some advantages in tensile strength, although it shows some disadvantages when it comes to tearing strength. The performance of a mixed-ingredient paper sheet falls between the performance of two pure-component papers. For cost and performance reasons, adding a small amount of Wikstroemia (e.g., <20%) to Edgeworthia is preferable.