Conversion from Paper Pulp to Cellulose Nanofibers（CNFs）

In this century, various methods have been found to separate “cellulose microfibrils” from plant cellulose fibers and to convert them into nanocellulose materials. Research and development of nanocellulose-containing organic and inorganic composites has been investigated for preparation of new functionalized materials in the world. If the production mass of nanocellulose is increased, the price of nanocellulose is expected to be reduced when paper pulps are used as the resources. The mass of production and consumption of nanocellulose materials will increase, if nanocellulose-containing polymer composites are achieved to have high strength, elastic modulus, and toughness even at small mass ratios of nanocellulose in the composites, resulting in a decrease in nanocellulose price. Partial substitution from metallic materials, reductions of the mass of fossil resources-based polymers and marine microplastics, and creation of a sustainable society based on biomass resources may be contributed by the quantitative and qualitative expansions of nanocellulose application and utilization. This is because nanocellulose materials are biosynthesized from atmospheric CO₂, and abundantly accumulated as cellulose microfibrils in plant bodies. The use of nanocellulose may also partly prevent and reduce the global environmental and resource issues. In the process of research and development for efficient preparation methods of new nanocellulose materials, various chemical pretreatments have been developed. These chemistry fields of plant cellulose fibers are categorized to new position-selective surface chemical modifications of crystalline cellulose microfibrils. These fields may open new technology of paper-like functional materials using chemically modified wood cellulose fibers containing abundant scaffolds for efficient counterion-exchanges with diverse cationic metal ions and alkylammonium ions under aqueous conditions.