Environmental Concerns Could Stall Growth, but For Now the Future are and Future
Petroleum-based fibers have led the race with renewable fibers in the last few years. In 2024, they dominated the fiber market with a share of more than 67%, sharply rising from 62% in 2018. The main reason for this rally is that their main competitor, natural fibers, stagnated with an annual output fluctuating around 330 million metric tons in this period, unable to satisfy the growing fiber demand – natural fibers’ market share dropped from 31% to 26%, and their loss is just what their competitor got.
t the same time, cellulosic fibers, another renewable fiber category, could barely catch up with the fiber growth. With a compound annual growth of more than 5% yearly, they kept a stable market share above 6% in the past six years. As bio-based synthetic fibers are still in their infancy, with a market share of less than 0.5%, cellulosic fibers are currently the only significant player in the race to replace petroleum-based fibers with sustainable alternatives.
Why Cellulosic Fibers?
Cellulose fibers are made from natural cellulose, which is part of all major plants and, consequently, the most widely available organic polymer on earth, with up to one trillion tons produced annually. The abundant and easily obtainable raw materials support the mass production of cellulosic fibers. Since their first industrial production of in 1905, cellulosic fibers had dominated the fiber market for six decades, until being surpassed by synthetic fibers in 1968.
Then, after a long decline of nearly three decades, cellulosic fibers revived at the beginning of the 21st century, mainly driven by the demand for hiking in China. With a compound growth rate of more than 6% per year from 2000 through 2010, their output finally overtook the previous historical high in 1973.
The success story continued in the following 14 years, partially due to the world’s hunger for green materials – cellulosic fibers are bio-based and biodegradable, which answer well to the world’s calls for sustainability and reduced carbon footprint. With a compound annual growth rate of more than 5%, the global output of cellulosic fibers reached a new high of 8.3 million metric tons in 2024. This trend will likely continue in the following decade, as the industry is now working on new solutions to clear the hurdles that could hurt the future of cellulosic fibers.
Viscose Fibers: Environmental Hurdles
Many hurdles could slow down or inhibit the growth of cellulosic fibers in the future. One significant obstacle is their environmental problems. Although cellulosic fibers are made from natural resources such as wood pulp and cotton pulp, their production is not necessarily “green” because the whole process may involve large water and energy consumption, the use of toxic chemicals, and wastewater and exhaust emissions. This is especially true in the production of viscose fibers, the first-generation cellulosic fibers.
Current research and development (R&D) for viscose fibers mainly focus on the further reduction of water and energy consumption, as well as the treatment of wastewater and exhaust emissions.
Today, more than 78% of the cellulosic fibers produced worldwide are still viscose fibers because they provide consumers with desirable performance at a relatively low cost. But it’s also well-known that they could pollute a lot, which is the main factor that inhibits their growth worldwide and also results in rising regulatory pressure. For example, in May 2024, the Chinese government published a new regulation for viscose fiber production, setting stricter rules on the facility scales, sodium sulfate recovery, water and energy consumption, recycling and treatment for wastewater and exhaust emissions, etc. As China produces more than two third of the world’s viscose fibers, this regulation holds the reins tighter against the pollution, and forces the industry to go for greener production.
A significant step to solving viscose fibers’ environmental problems happened in 2017 when the Austria-headquartered Lenzing launched its EcoVero™, a viscose fiber that uses 50% less water and emits 50% less CO2 compared to generic viscose fibers. Similar efforts continue in other places in the world. This progress reduces the public discontent against viscose fiber facilities, thus helping viscose fibers continue their growth.
Current research and development (R&D) for viscose fibers mainly focus on the further reduction of water and energy consumption, as well as the treatment of wastewater and exhaust emissions. For example, some producers have developed biological methods to remove carbon disulfide (CS2) and hydrogen sulfide (H2S) from exhaust emissions. One of these producers is the China-based Hiest, whose method includes patented technology for growing microorganisms that naturally form a biomembrane system, capable of degrading more than 95% of H2S in the exhaust emissions from viscose fiber production.
Lyocell: Booming Capacity
Another method for removing environmental hurdles is to expand the capacity of lyocell fibers. As the third-generation cellulosic fibers, lyocell is made through a closed-loop process, resulting in almost zero waste. With these environmental advantages, lyocell fibers grew much faster than viscose fibers in the past decade. In 2024, more than 600 thousand metric tons of lyocell fibers were produced, up more than 20% from the previous year, compared to the 5% growth from viscose fibers in the same period.
Current R&D for lyocell fibers mainly focus on reducing the water and energy consumption in manufacturing process, which will make them even more environmentally favored. They actually gain more momentum – by late 2024, the lyocell fiber projects under construction totaled at around one million metric tons, which means that the manufacturers are very optimistic about the strong growth of production and consumption for the next few years.
Recycled Raw Materials: Green and Functional
Manufacturers are also working on increasing cellulosic fibers’ environmental advantages by integrating recycled materials, such as waste plastics and textiles, into raw materials. Examples include Lenzing’s EcoVera™ with Refubra viscose fibers, which use up to 20% of recycled raw material content from post-consumer textile waste, and the China-based Sateri’s Finex, short for “Fiber Next,” is a cellulosic fiber made from a mix of recycled pre- and post-consumer textile waste, as well as wood pulp from renewable plantations.
Recycled materials can even go further for making cellulosic fibers with additional functions. For example, a research team from Donoghue University, led by Pro. Mao Zhiping, has developed a high-strength and electrically conductive cellulosic fiber from waste cotton with polypyrrole (PPy), which has a potential being used for making temperature sensors or electrically heating textiles.
Breaking the Limits
Although they have environmental and many other advantages, cellulosic fibers also have some disadvantages that limit their applications to a bigger stage to compete with their petroleum-based counterparts. Examples include fibrillation, damage, flammability, and mildew. Solving these problems will help cellulosic fibers go beyond their limits and continue to tell the world a success story.
One of the main disadvantages of lyocell textiles is that they tend to fibrillate in the wet state, limiting their use in many applications. In addition to using the fibrillation feature to create fabric with special effects, researchers are working on reducing the fibrillation in various ways and in various steps of the manufacturing process. For example, the China-based Transfar, a chemistry company, has developed a method that reduces fibrillation by deeply linking cellulose molecular chains in the printing and dyeing. This invention solves the fibrillation problem without increasing the cost or complexity of the manufacturing process.
Another disadvantage is that cellulosic fibers are usually very flammable, with a low limiting oxygen index (LOI) of 17-19%. LOI is used to measure the flammability of materials, and if it is below 21%, the material can burn easily in normal atmospheric conditions.
Currently, there are three main methods for producing flame-retardant cellulosic fibers: blending modification, graft copolymer, and finishing. The bending modification method mixes flame retardants with cellulosic solution, producing fibers through a wet spinning process. One of the current focuses for bending modification is to use bio-based flame retardants, which help the fibers maintain their advantages in sustainability while achieving the flame-retardant goal. By far researchers have developed various types of bio-based flame retardants from starch, protein, lignin, chitosan, cyclodextrin, and other natural sources, which can raise the cellulosic fibers’ LOI to more than 35%, showing a great potential for further industrial production.
Another disadvantage is that cellulosic fibers easily mildew, resulting in damage and color change on textiles. Therefore, researchers are developing antibacterial agents to help cellulosic fibers prevent the spread of mildew while providing additional health benefits to the textiles. One of the current focuses of R&D is bio-based antibacterial agents such as chitosan, sorbic acid, and hinokitiol. These natural antibacterial agents are safe and non-toxic with excellent biocompatibility, which makes the antibacterial cellulosic fibers made from these natural agents suitable for food, cosmetic, and medical applications.
Another disadvantage is that cellulosic fibers are often easily damaged in the manufacturing process, for example, in the process of making nonwoven. The damage could cause surface problems and reduce the strength of nonwoven products. Specifically, tailored production equipment and machines are often required to facilitate the use of cellulosic fibers in these applications.
The Future Outlook
Looking ahead, the future of cellulosic fibers will be shaped by how effectively the industry addresses its environmental and technical challenges. While cellulosic fibers have regained momentum thanks to their renewable origins and biodegradability, ongoing concerns about water and energy use, chemical pollution, and product limitations remain significant hurdles. Innovations such as closed-loop lyocell production, integration of recycled materials, and the development of bio-based additives for flame retardancy and antibacterial properties are already paving the way for a greener and more versatile fiber market. If these advances continue and scale, cellulosic fibers are well-positioned to play a leading role in the transition toward more sustainable textiles, offering a viable alternative to petroleum-based fibers while meeting the growing global demand for eco-friendly materials.
