With technical advances in the field of cellulose nanomaterials such as cellulose filaments (CFs) and cellulose nanocrystals (CNCs), the development of functional forest-based materials could lead to enhanced applications in multiple industries: intelligent packaging, cosmetics, paints and coatings, foods, and advanced electronic and photonic materials, among others.
Forest-based products have long capitalized on lignocellulosic biomass which yields fibres that are processed to meet many different requirements, such as superabsorbent hygiene products, ultrasoft tissue products, or ultralightweight coated paper. Now, new forest-based functional materials have the potential to compete with other materials, based not only on performance, but on the merits of being a CO2-neutral, renewable, and recyclable resource. In addition to costeffectiveness and product differentiation, the forest industry is considering new technologies to healthily grow and secure long-term, respectable return on investment.
The competitiveness of forest-based materials rests on linking product development with the concept of fibre engineering and selective design by using new technical tools to manipulate and restructure fibres, and their constituents, on as small a scale as possible, including the molecular scale, to add functionality.
Owing to their market potential, a variety of fibrillated cellulose products, including cellulose microfibrils (CMFs) and cellulose nanofibrils (CNFs), have been produced using low-consistency mechanical treatment procedures. However, high energy consumption is required for mechanical fibre delamination at low consistency. To reduce the total energy consumption, numerous chemical or enzymatic pretreatments have been used in conjunction with mechanical processing.
The CF production process, developed by FPInnovations, has several key advantages compared to CMF and CNF production. CF can be produced at high consistency from all types of wood pulps, bleached or unbleached, without additional mechanical, chemical, or enzymatic pretreatment. A much higher production rate can be achieved in either continuous multi-pass or batch mode owing to the higher operating consistency. Using commercially available equipment to produce mechanical pulps may reduce the capital cost for commercialization, and has the potential to revive pulp mills that are idle due to market decline in newsprint and other paper grades.
In contrast, CNCs are produced by only chemical processes. Typically, a strong mineral acid such as sulphuric acid is reacted with bleached wood pulp under controlled conditions of acid-to-pulp ratio, temperature, and time to optimize CNC yield. Neutralization of the acidic sulphate groups introduced onto the CNC surfaces with sodium hydroxide, for example, improves the product’s thermal stability. It also allows CNC aqueous suspensions to be spray-dried to provide a powder that is easily transportable and subsequently, redispersible in water or polar solvents.
Canada is well-positioned to lead the world in making serious contributions to devising an economically responsible, science-based agenda for the bioeconomy of the 21st century. The potential for creating cellulose nanomaterials with tailor-made functionalities and responsiveness is also remarkably exciting and promising.
Significant work lies ahead: collaborative efforts between scientific and engineering disciplines and industrial expertise are essential for overcoming the challenges, and ensuring the development of methodologies for technological success and potential commercialization of the wide range of applications.