Proceeding Articles

Nippon Paper industries has been developing Cellulose Nanofibre (CNF) products prepared by the fibrillation of chemically modified pulp since 2007.

In November 2013 we started to operate a pre-commercial plant in order to provide CNF for the collaborators, potential users and internal use, after 5 years of fundamental research together with out collaborators with the aim of commercialization of products using CNF. In our pre-commercial plant, mainly TEMPO oxidized CNF is produced, a process developed by the research group of Prof. A. Isogai at The University of Tokyo. In addition t TEMPO oxidation, other chemical modifications such as carboxymethylation are carried out in out plant as well. Thus collaborators can choose the type of CNF samples, depending on their target applications.

In 2016, NPI announced the plan to install a CNF full-scale production facilities at the Ishinomaki Mill and the Gotsu Mill in Japan. At the Ishinomaki Mill, CNF prepared by TEMPO oxidation will be produced, and at the Gotsu Mill, CNF prepared by carboxymethylation will be produced.

In this brief paper we will present our developments of manufacturing techniques and applications of chemically modified CNF

In this work, the pulp fibers were enzymolyzed to prepare the nano-sized cellulose (NC). The as-prepared samples were characterized by optical microscopy, electron microscopy, and Raman spectra. The experimental results indicated that enzymatic hydrolysis of pulp fibers could produce the spherical NC with a mean particle size of about 30 nm, which has the excellent monodispersity and uniformity. When the concentration of complex enzymes was 20 u/mL (cellulase: xylanase = 9:1), the yield of NC was 13.6%. The single cellulase was used, even if the concentration and time reached up to 200 u/mL, only a mixture of trip and granular flocculation were obtained. The positive synergistic effect between xylanase and cellulase could be due to the enzymolysis of hemicellulose located on the cellulose microfibers to favorable of cutting and splitting of the microfibers by the endoglycannase in cellulase. Otherwise, the additive copper sulfate could decrease formation of reducing sugar effectively.

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A classification of the wide variety of solids according to physical, structural and chemical characteristics shows the category of heterophase solids to be the largest group of natural and artificial substances. Most manufacturing and manufactured materials fall in this category.

The structure of such materials can be described by the shape, size, concentration, orientation and topology of the constituent phases. Statistical methods in particular, geometric probability sometimes supplemented by certain physical ortopological restrictions, provide adequate tools for the description of naturally grown or artificially mixed systems.

Mechanical modulus properties as well as thermal and electrical properties can be treated in a fairly general manner,based either on field distortion of one phase by the presence of another phase or by means of phase models that give upper and lower limits for the property.

The problem of strength properties can be seen in terms of fracture mechanisms or as a statistical one, in which case extreme value theory provides a suitable method.

Organic polymers have always been useful for the making of fibres, films, rubbers, plastics, adhesives and coatings and cover a wide range of properties. For several years, systematic efforts have been made to explore the use of fully synthetic fibres on a paper machine either alone or together with cellulose materials. Several sheet properties can be substantially improved by this approach. More recently, the preparation of polymer systems has been studied that occupy an intermediate position between a uniform fibre and a homogeneous film. They have been called `fibrids’ and permit one to prepare two-dimensional sheet-like entities without the use of a liquid vehicle (such as water on a papermachine) that range in their properties from paper to textiles.

This paper is a condensed survey of the interactions between water and cellulose materials. It is introduced by some general remarks about the interaction of water with solids, with special attention to hydrogen bonds, solutions and gels, then about the chemical and physical properties of cellulose fibres. The main discussion is devoted to the interaction of water below and above the saturation point, dimensional changes and restricted swelling, drying and hysteresis and, finally, the quantitative measurements of the absorbed water.

Equilibrium water retention isotherms have been determined for papermaking fibres through the range of moisture contents that is of greatest papermaking interest.

The experimental method provides not only a measure of the swelling of the fibres and the equilibrium water retention at any force of water removal, but, conversely, the method measures the force with which the water is held and the force with which fibres or fibre elements are held together by residual water.

Factors affecting the mechanism of water retention and the amount of water held by fibres are demonstrated by the isotherms of model and papermaking fibres of widely varying properties and treatments. The part played by the mechanism and extent of water retention on the development of wet web properties during drying is discussed and the need is demonstrated for more information than is provided by the isotherm.

Finally, consideration is given to the role of swelling and water retention in pulp evaluation and some general principles are suggested by which the running and papermaking properties of a pulp might be predicted.

Micro-radiography has been used to determine the width and moisture content of individual pulp fibres during their drying from the swollen state. The method, which employs soft X-rays to produce contact radiographs of the fibres, is described and results are given for a spruce sulphite wood pulp. An assessment of changes in the thickness of the fibres while drying is also given.