Chemical Carbonization in Solid-Phase of Nano-Size Cellulose Containing in Plant and Wood Pulp, and Relating Properties of the Carbonized Cellulose Fibers

Abstract

Plant fibers used for paper and textile are mainly composed of cellulose microfibers which are gathered in the form of hierarchical structures in the plant cell wall. The microfibers are often obtained in the form of pulp from wood, sisal, abaca, and bamboo. Cellulose nanofibers (CNFs) are able to separate from the microfibers. This paper reports that the microfibers are composed of lots of CNFs oriented parallel to the microfiber axis, using electron microscopes. The morphological properties of the microfibers mentioned above are almost retained after the chemical carbonization at a temperature of 800℃ using methane sulfonic acid (MSA) or Iodine (I₂) as a catalyst for the carbonization. MSA is more effective for the carbonization than Iodine. CNFs added to bamboo papers are enhanced the mechanical and electrical properties of the bamboo papers in both of the case before and after the carbonization. CNFs obtained from wood pulp, so called, TEMPO oxidized CNFs, show a needle-like structure in nanometer-size after the chemical carbonization.