Although many people are not aware of it, textile materials are important components of the energy and sustainability equation. Not long ago, the public, generally, knew little about the textile materials in products such as layered fabric face masks. That all changed as the entire world turned to wearing them in response to the danger of COVID-19 infection.
But there are many more applications that play important roles in a sustainable and healthy future. Fibrous substrates contribute to energy savings, help with developing greener materials for a sustainable infrastructure and can even serve as energy harvesters.
Energy and economics
In the past few decades, the textile sector—from the production of raw materials to making garments—has been working to conserve energy to reduce the overall cost of manufacturing. While the major cost component of a textile product is the raw material, it is estimated that about 6–10 percent of the cost of manufacturing is from energy consumption during manufacture.
But the price of raw materials is primarily a fixed cost, so there may be little leverage available to save on these expenses. Furthermore, the prices of fibers—both natural and synthetic—are dependent on many factors. For synthetics, such as polyester and polypropylene, the price is directly correlated with the price of oil. In the case of natural fibers such as cotton, the price is dependent on even more volatile factors, including the weather in any given year. Therefore, textile businesses are more likely to focus on the manageable and variable costs, and that includes energy.
Energy is the heart of manufacturing; process optimization, machinery maintenance and regular energy audits are, therefore, essential. In conventional textiles, a spinning operation has several precursor processes, such as the blow room operation and carding, which involve heavy machinery. Proper machinery alignment and correct belt usage and maintenance will support energy conservation, and a regular energy audit can also help to mitigate inefficiencies.
Professional associations, too, can help the industry with information about how to save energy and manage costs. For example, SITRA, the Coimbatore, India-based South India Textile Research Association, has undertaken numerous energy studies and has made available useful educational materials for the textile industry.
According to Mirza Khyum, who has experience as a production officer for Thermax Check Fabrics Ltd., Bangladesh, “The reduction of energy consumption in any phase of manufacturing can save enormous costs and resources. As a result, carbon emissions will be reduced to safeguard Mother Nature. Some factories are reusing the process waste to produce quality goods to advance the approach of conserving resources,” says Khyum. Bangladesh is the second-largest manufacturer of ready-made clothing in the world.
The textile sector, generally, is making efforts to conserve energy as a way to cut manufacturing costs, but it also seeks to be good stewards of the environment. Process optimization steps starting with raw materials can make a significant difference in the larger energy use picture.
Cotton, for example
In the case of natural fibers, precision agriculture to conserve on chemical use, such as herbicides and pesticides—and, more importantly, water—is being practiced. West Texas, one of the world’s leading cotton producing regions, has been a pioneer in growing cotton and other rotation crops with fewer resources. Most of the cotton crop grown there is dryland, which depends on rain during the growing season. Even in places of irrigated production, that irrigation is supplementary.
Producer support groups such as the Lubbock, Texas-based Plains Cotton Growers Inc. and state systems such as the Agriculture Experimental Stations regularly offer educational and outreach programs on water conservation, as the water usage is directly related to water pumping and power use.
As part of its 10-year sustainability initiative, the entire U.S. cotton industry is endeavoring to enhance the efficiency of fiber production. The industry’s goal is to decrease energy use by 15 percent, which cotton producers manage via a multifaceted approach that includes reducing tillage and the use of nitrogen fertilizer. This goal also focuses on reducing greenhouse gas emissions by 39 percent, decreasing water usage by 18 percent, increasing land use efficiency by 15 percent and increasing soil carbon by 30 percent.
Textile material applications
Advanced textiles such as nonwoven mats have important roles to play in conserving energy. Glass fiber mats manufactured via carding and chemical bonding are used in insulating materials for homes and commercial buildings. These fibrous materials are common between roofing structures and the gypsum-based drywall sheets.
The necessity of such insulation products has become clear after the power outage crisis due to winter storms in Texas. One of the reasons for the failure was lack of adequate weatherization of the natural gas pipelines.
Commonly used housing infrastructure products play a vital role in conserving energy and are indeed industrial textile products. Home furnishing items, such as window blinds and draperies, or coated textiles in PVC finished products find applications in many ready-to-build structures. Temporary shelters used as COVID-19 testing centers and vaccination sites were erected quickly and efficiently to deal with specific crises, without requiring the material and energy resources of a permanent structure.
There are many less obvious, but equally useful, products worth noting. The HVAC filters used in homes filter dust in the ventilation and humidity control pipes, thereby reducing the energy load and increasing the efficiency of heating and cooling units. Normally these pleated filters are made using bonded staple fiber nonwoven webs. Floor mats and carpets not only provide aesthetic value, but more importantly serve as insulating materials.
It is estimated that there are about 40 different textile-based items in an automobile. High-loft nonwovens are used as heating, ventilation and acoustic insulators. Air filters and engine filters are necessary components to keep an automobile running. Automobile manufacturers are looking into utilizing recycled materials to replace metal components wherever possible to reduce the overall weight of an automobile. Other industrial textile materials in an automobile—headliners, trunk liners and insulators, for example—help to reduce fuel consumption.
Textile substrates and composites are used in energy harvesting, as well. Windmill blades are relatively lightweight composites, made strong by using carbon fiber and other high-tech fibers for strength. Lithium-ion batteries use fiber-based separators to separate the anode and cathode electrodes. Cellulose-based wet-laid materials are common separators, in addition to those made from natural and synthetic fibers.
Hollingsworth & Vose, a global supplier of advanced textile materials, has been a pioneer in developing battery separators, building on its years of experience in the development of wet-laid nonwovens. LIELSORT®, a product from Japanese producer Teijin Ltd., utilizes microporous polyethylene to develop the separators. But with recent supply chain interruptions, one can expect developed economies to invest heavily in these advanced products to reduce dependency on producers in other countries for the materials.
A way forward
The Biden administration has a plan to invest about $1.2 trillion over eight years to rebuild infrastructure in the U.S. This will offer an opportunity for using advanced and sustainable materials in building energy-efficient structures. Particular attention is being paid to climate change in this initiative, which necessitates reduced greenhouse gas emissions throughout the process.
Geosynthetics, insulation products and soft composites will be amply utilized in future construction projects, spurring more research and development. This suggests that manufacturers of advanced textile products can undoubtedly anticipate growth in the near future.
Seshadri Ramkumar, Ph.D., is a professor in the Nonwovens & Advanced Materials Laboratory, Texas Tech University, Lubbock.