The Elusive Fibre

Scouring through old journals and magazines can throw up fascinating snippets about the past, and many of those can catch you by surprise, and set you thinking all over again. Scraping websites for cotton alternatives, at some point, can well take one to a particular report from the proceedings of a textiles-related event would make for interesting reading. It goes thus:

Speaking at the annual meeting of the Bradford Dyers’ Association, recently, Sir Milton Sharp, observed that the deplorable condition of the cotton trade was chiefly due to the high price of raw material. He expressed the opinion, however, that the prospect of freeing the cotton manufacturing industry from entire dependence upon the cotton crops of the world was not impossible of realisation. It was within the range of possibility that properly directed scientific research would find means of producing a fibre which, although not exactly offering a substitute for cotton, would supplement the supply of cotton just as artificial silk had supplemented natural silk. Besides the possibility suggested, he thought it was certain that some day an alternative plant would be discovered equally capable of yielding suitable fibre in adequate quantity and which could be cultivated with less skill, care, and risks than were associated with cotton cultivation.

At first glance, the quote would appear to be from a report about an event organised last month, or probably last year; except, that it is not. Sir Milton, a wealthy dyer from Yorkshire, in fact died in May 1924. And, the extract in question is from a 1923 issue of the Journal of the Textile Institute Proceedings. The headline of the report too is telling: High Cost of Cotton: Alternative Fibres. Sharp was not prophetic in the sense that he did not predict what would happen in the future; but yet, he had outlined the need for a fibre that would be an alternative to cotton. Twisting this around, the quest for an alternative fibre is nothing new: it has time and again cropped up in the discourse for close to a hundred years, possibly more if one could keep digging into the past.

What has perceptibly changed since Sir Milton expressed his concerns about the problems of cotton roughly a century ago is that terminologies have interminably changed. Today, the quest is that for a sustainable product, be it in the form of a natural fibre or a smart textile.

A Twist in the Tale

In the last week of August this year, the announcement about the discovery of a new yarn sent the textiles industry into a tizzy. An international research team led by scientists at the University of Texas at Dallas and Hanyang University in South Korea were reported to have developed high-tech yarns that generate electricity when they are stretched or twisted. In a study published in the August 25 issue of the journal Science, researchers described “twistron” yarns and their possible applications, such as harvesting energy from the motion of ocean waves or from temperature fluctuations. When sewn into a shirt, these yarns would serve as a self-powered breathing monitor.

The discovery, as it were, caught the attention of the textiles-apparel industry, researchers interested in energy issues, and those concerned with emerging technologies and the Internet of Things. The announcement presented a convergence of interests and concerns.

A statement issued by the University of Texas at Dallas summed up the exhilaration of the researchers: “The yarns are constructed from carbon nanotubes, which are hollow cylinders of carbon 10,000 times smaller in diameter than a human hair. The researchers first twist-spun the nanotubes into high-strength, lightweight yarns. To make the yarns highly elastic, they introduced so much twist that the yarns coiled like an over-twisted rubber band. In order to generate electricity, the yarns must be either submerged in or coated with an ionically conducting material, or electrolyte, which can be as simple as a mixture of ordinary table salt and water.” It was a technological wonder, and much of the excitement would have been lost in the scientific jargon, most of which would have been gobbledygook to a lay person.

The announcement tried to contextualise the discovery. The researchers showed that a twistron yarn weighing less than a housefly could power a small LED, which lit up each time the yarn was stretched. And, to show that twistrons can harvest waste thermal energy from the environment, they connected a twistron yarn to a polymer artificial muscle that contracts and expands when heated and cooled. The twistron harvester converted the mechanical energy generated by the polymer muscle to electrical energy. “The researchers also sewed twistron harvesters into a shirt. Normal breathing stretched the yarn and generated an electrical signal, demonstrating its potential as a self-powered respiration sensor.” Everyone, expectedly, said, “Wow.”

Ray Baughman, director of the NanoTech Institute and a corresponding author of the study, was quoted, “Electronic textiles are of major commercial interest, but how are you going to power them? Harvesting electrical energy from human motion is one strategy for eliminating the need for batteries. Our yarns produced over a hundred times higher electrical power per weight when stretched compared to other weavable fibres reported in literature.”

But much of this would remain a marvel on paper certainly for a while, and for a number of reasons. This is not going to change the world till a level of mass production is reached, and the high costs involved would be beholden to economies of scale. Till then, twistron remains of academic interest.

Yarning for a Better Future

Twistron is only the latest, and perhaps the most exciting, of the new discoveries and inventions that have been in the news in recent times. There has been a flurry of activities in the textiles and apparel world of late, and companies have been making huge investments in research and development (R&D) ventures. The reasons are many, the most pressing of them being the imperative need to cut down costs, and to meet the demands of consumers craving for sustainable fashion.

The hype over twistron has precedents. Last year, researchers at the Georgia Institute of Technology, Atlanta (US) had announced the development of a fabric that can simultaneously harvest energy from both sunshine and motion. “Combining two types of electricity generation into one textile paves the way for developing garments that could provide their own source of energy to power devices such as smartphones or global positioning systems,” they announced, after the research was reported in the Nature Energy journal in September 2016.

The hybrid textile was presented as “a novel solution to charging devices in the field from something as simple as the wind blowing on a sunny day.” The research team used a commercial textile machine to weave together solar cells constructed from lightweight polymer fibres with fibre-based triboelectric nanogenerators. “Triboelectric nanogenerators use a combination of the triboelectric effect and electrostatic induction to generate small amount of electrical power from mechanical motion such as rotation, sliding or vibration.” The long and short of the technological geekspeak was that this fabric, only 320 micrometres in thickness, when woven together with strands of wool could be integrated into tents, curtains or wearable garments. Now, this was a fabric that would be highly flexible, breathable, light weight and adaptable to a range of uses.

It would be obvious that harnessing energy—be it solar, wind or thermal—comes across as one of the prime drivers for new fibres, yarns and fabrics in most research initiatives. A similar announcement had been made by the Vanderbilt University, Tennessee, this summer. A new, ultrathin energy harvesting system developed at the university’s Nanomaterials and Energy Devices Laboratory was claimed to be an invention whereby garments will soon be able to power cellphones, fitness trackers and other personal electronic devices as one walks, waves and even when one is sitting down. “Based on battery technology and made from layers of black phosphorus that are only a few atoms thick, the new device generates small amounts of electricity when it is bent or pressed even at the extremely low frequencies characteristic of human motion,” the university announced, following up on system described in a paper published by the journal ACS Energy Letters.

A deep dive into history shows that research into e-textiles, or what one refers to as smart textiles, is nothing new. The Wikipedia entry on the subject starts its history section thus: “The basic materials needed to construct e-textiles, conductive threads and fabrics have been around for over 1,000 years. In particular, artisans have been wrapping fine metal foils, most often gold and silver, around fabric threads for centuries. Many of Queen Elizabeth I’s gowns, for example, were embroidered with gold-wrapped threads.” Today’s research attempts are not new; they have only become better.

This fact is in sync with the earlier reference about Sir Milton and his foresight about alternative fibres. The enquiry into e-textiles is, to put in a cliched way, age-old. Harnessing electricity to power gadgets and heavy-duty machines was possible only in the late 19th century. And it is only now that the same knowledge is being applied as wearables. It only gets better with every new innovation.

Taking the Path of Nature

After the need to become environmentally responsible was driven home by the United Nations Conference on Environment and Development (UNCED), also known as the Rio Summit or Earth Summit, in June 1992, research into inventions and innovations in the textiles and apparel industry, as in any other industry sector or segment of society, got a direction. Activities, however, remained confined to efforts of likeminded individuals or groups. A concerted effort came only towards the fag end of 2006 when the United Nations (NA) General Assembly proclaimed 2009 as the International Year of Natural Fibres (IYNF) and invited the Food and Agricultural Organization (FAO) to facilitate its observance, in collaboration with governments, regional and international organisations, non-governmental organisations, the private sector and relevant organisations of the UN system.

It was a good start. The IYNF was able to raise the profile of natural fibres, thereby strengthening demand, promoting efficient and sustainable industries and contributing to improved welfare of fibre producing farmers. It also brought allied natural fibre industries together for mutual support in the communication of the importance and benefits of natural fibre industries. After all, sustainable fashion cannot be an all-encompassing reality till the entire system is democratised. Towards this, the role of inter-governmental organisations and their influence is crucial.

One of the spinoffs of the IYNF was the Future Fibres Initiative (FFI). Established in December 2010 with support from the German ministry of food, agriculture and consumer protection, the FFI set out to give much needed support to sisal and other hard fibres. According to the FFI website, the  initiative strives to: advance technology transfer under south-to-south cooperation and under north-to-south cooperation; advocate equitable business models that reward farmers and other agents for their enterprise; encourage the adoption of ethical social practices including advancing gender equality; and encourage ‘responsible choices’ in the market place that are in concordance with the bio-based economy via sustainability promotion. There is, however, hardly any textile component here with the focus being on sisal, which is used in composite materials for cars, furniture and construction as well as in plastics and paper products.

But the other initiative had textiles at its core. As the IYNF drew to a close, representatives of 15 natural fibre organisations formed the Discover Natural Fibres Initiative (DNFI) to continue to support the objectives of IYNF. The DNFI “highlights activities to promote greener and more efficient agricultural techniques for growing natural fibres, efforts to improve life of the poor who are involved in natural fibres and to encourage increased demand for natural fibres.” Comprising an alliance of international natural fibre associations with emphasis on textiles, such as Cotton Council International (CCI), International Cotton Advisory Committee (ICAC), Bremen Cotton Exchange, International Textile Manufacturers Federation (ITMF), International Wool Textile Organization (IWTO), the DNFI has been building on the achievements of the IYNF 2009.

This year onwards, the DNFI is stepping up its promotional activities. It has instituted the DNFI Innovation in Natural Fibres Award to “promote the development of new products/components and applications using natural fibres as well as new processes for manufacturing of environmental friendly products.” Universities, institutes, industry and individuals working in the area of scientific research have been invited to participate. “Sustainability” should be just one important aspect of each submission considered by the judges. The winners will be announced in October.

The third is not exactly a spinoff, since the Intergovernmental Group (IGG) on Jute, Kenaf and Allied Fibres predates the IYNF. The IGG is a forum for intergovernmental consultation and exchange on trends in production, consumption, trade and prices of jute, kenaf and allied fibres, including regular appraisal of the global market situation and short-term outlook.

Tiny Steps, Yawning Gap

Most of the debates about alternative, nay sustainable, fibres or yarns hover around new-fangled or upcoming products. It would also be worthwhile to look at existing fibres, especially those occurring naturally, that are being used to produce fabrics and garments. There are, thankfully, many. But unfortunately, most of these either remain niche or operate on an extremely minute scale. If a difference has to be made, all these would need to scale up, and go the whole hog.

In this backdrop, new discoveries about what the world has come to also underline the need to proceed on a war footing. Only this July, researchers from the University of Leeds and Plymouth University found that polyester and acrylic clothing shed thousands of plastic fibres each time they were washed, sending another source of plastic pollution down the drain and, eventually, into the ocean. The numbers they threw up were staggering: their “laundry science” revealed that an average UK washing load—6kg of fabric—can release: 140,000 fibres from polyester-cotton blend, nearly half a million fibres from polyester, and more than 700,000 fibres from acrylic. For a planet, whose oceans cover more than two-thirds of the surface area, this should be an unnerving fact. With such level of contamination of the oceans, the world need to move away from such fibres—right away, before the oceans choke up as well.

The consumption of textiles is growing at a faster rate than that of the global population. Producing mass quantities of a water-intensive crop like cotton is problematic in itself, and the so-called man-made fibres (MMFs) are causing untold damage on the planet, most of which is yet to be documented properly. Humanity is caught between the devil and the deep sea. And when one adds to this backdrop the issue of consumption of resources like water and energy (which, in turn, also has a water component), what comes out of it is a very distressing picture.

For all its faults, cotton is less problematic than its alternatives, certainly the organic variant of it. According to the “Life cycle assessment (LCA) of organic cotton—A global average”, published by the non-profit Textile Exchange in 2012, organic cotton has significant advantages in comparison with conventional cotton. It causes 46 per cent less greenhouse gas emissions, 70 per cent less soil salinisation and 26 per cent less soil erosion. It uses 91 per cent less land and groundwater and 62 per cent less energy. With competition for arable land becoming tougher by the day, organic cotton producers will have to find a new and innovative way out. And, fast at that.

Among the alternatives that abound is viscose. This too needs to remain under the scanner, because unless the process is transparent, it can lead to wanton destruction of forests. There have been reports in the recent past about companies sourcing from those who have been indulging in illegal destruction of forests around the world. For viscose to grow and remain sustainable, the entire supply chain of all viscose that is the market needs to be transparent and traceable. After all, not every company is like Lenzing which was in November 2016 rated number one globally with respect to their procurement of wood, the key raw material in cellulose fibre production. This was the conclusion of the global ranking compiled by Canopy Planet Society, a Canadian non-profit organisation that works closely with 68 leading retail brands in the textiles industry worldwide, and is reckoned to be a driver in evaluating sustainable sourcing processes. But not every company has Lenzing’s cutting-edge technology, or can operate at the company’s sheer scale. If sustainable, viscose certainly needs to be kept in mind: the fibre yields per hectare of forests are up to four times higher than those of cotton, measured by kilogrammes per year. Moreover, trees can be cultivated without artificial irrigation and pesticides, and that too in managed forests and not plantations.

All other alternative ventures have made no headway at all, and remain confined to such minuscule levels to be even noticed. Everyone has heard of the immense possibilities of, say, flax and hemp. Both have been around for thousands of years, with earliest-known usage of hemp dating back to 8,000 BC. Both are excellent alternatives to cotton, and do not need fertilisers or pesticides. Linen, derived from flax does have a market, but remains out of the reach of many people. Therein certainly lies a logistical problem. Just the fact that a fibre has been sustainably grown and the resultant garment has been sustainably sourced would mean zilch unless it is affordable.

After all, it was not without reason that MMFs became popular in the second half of the previous century: an ordinary worker could buy two polyester shirts for the price of a cotton one, give or take. This certainly poses a challenge to research institutions and companies searching for that elusive alternative fibre. Then again, does there need to be just one alternative fibre? Can different alternative fibres be positioned differently? Of what use can be a particular fibre if costs are so prohibitive that it cannot have a miss dimension? Why should industry be caught in a bind where one company asserts that “my” alternative is better than “yours”?

Today’s efforts are sporadic, scattered and occasionally work at cross-purposes too. There are far too many organisations and associations working on sustainability issues and alternatives. That’s where the scope lies—of synergising efforts towards that alternative world.

15 of the world’s major plant and animal fibres

# Plant fibres

• Abaca: It’s a leaf fibre, composed of long slim cells that form part of the leaf’s supporting structure. Lignin content is a high 15 per cent. Abaca is prized for its great mechanical strength, buoyancy, resistance to saltwater damage, and long fibre length—up to 3m. The best grades of abaca are fine, lustrous, light beige in colour and very strong. Once a favoured source of rope for ship’s rigging, abaca shows promise as an energy-saving replacement for glass fibres in automobiles.
• Coir: Among vegetable fibres, coir has one of the highest concentrations of lignin, making it stronger but less flexible than cotton and unsuitable for dyeing. The tensile strength of coir is low compared to abaca, but it has good resistance to microbial action and salt water damage. A coarse, short fibre extracted from the outer shell of coconuts, coir is found in ropes, mattresses, brushes, geotextiles and automobile seats.
• Cotton: It’s almost pure cellulose, with softness and breathability that have made it the world’s most popular natural fibre. Fibre length varies at 10–65mm, and diameter at 11–22 microns. It absorbs moisture readily, which makes cotton clothes comfortable in hot weather, while high tensile strength in soap solutions means they are easy to wash. Cotton is the world’s most widely used natural fibre and still the undisputed “king” of the global textiles industry.
• Flax: Like cotton, flax fibre is a cellulose polymer, but its structure is more crystalline, making it stronger, crisper and stiffer to handle, and more easily wrinkled. Flax fibres range in length up to 90 cm, and average 12–16 microns in diameter. They absorb and release water quickly, making linen comfortable to wear in hot weather. One of nature’s strongest vegetable fibres, flax was also one of the first to be extracted, spun and woven into textiles.
• Hemp: Long, strong and durable, hemp fibres are about 70 per cent cellulose and contain low levels of lignin (around 8–10 per cent). The fibre diameter ranges at 16–50 microns. Hemp fibre conducts heat, dyes well, resists mildew, blocks ultraviolet light and has natural anti-bacterial properties. Shorter, woody core fibres (“tow”) contain higher levels of lignin. Easy to grow without agrochemicals, hemp is used increasingly in agro-textiles, car panels and fibreboard, and “cottonised” for clothing.
• Jute: Dubbed the “golden fibre”, jute is long, soft and shiny, with a length of 1–4m and a diameter of 17–20 microns. It is one of nature’s strongest vegetable fibres and ranks second only to cotton in terms of production quantity. Jute has high insulating and anti-static properties, moderate moisture regain and low thermal conductivity. The strong threads made from jute fibre are used worldwide in sackcloth - and help sustain the livelihoods of millions of small farmers.
• Ramie: It is white with a silky lustre, similar to flax in absorbency and density but coarser (25–30 microns). One of the strongest natural fibres, it has low elasticity and dyes easily. Strands of ramie range up to 190 cm in length, with individual cells as long as 40 cm. Trans-fibre fissures make ramie brittle but favour ventilation. Not widely known outside the East Asian countries that produce it, ramie is lightweight, silky and made for summer.
• Sisal: Lustrous and creamy white, sisal fibre measures up to 1 m in length, with a diameter of 200–400 microns. It is a coarse, hard fibre unsuitable for textiles or fabrics. But it is strong, durable and stretchable, does not absorb moisture easily, resists saltwater deterioration, and has a fine surface texture that accepts a wide range of dyes. Too coarse for clothing and upholstery, sisal is replacing glass fibres in composite materials used to make cars and furniture.

# Animal fibres

• Alpaca: It is partly hollow, from 20–70 microns in diameter and comes in 22 natural colours. It is light, stronger than sheep’s wool, and provides excellent insulation. Huacayo alpacas produce soft, dense, short fibres, while the fleece of the rarer suri is lustrous, silky and straight. Alpaca blends well with wool, mohair and silk. Soft and dense, or lustrous and silky, alpaca is used to make high-end luxury fabrics and outdoor sports clothing.
• Angora: The silky white hair of the angora is a hollow fibre classed as wool. With a diameter of 14–16 microns, it is one of the silkiest animal fibres. Angora wool is very soft to the touch, thanks to the low relief of its cuticle scales. Fine, silky and exceptionally soft to the touch, the wool of the Angora rabbit is used in high quality knitwear.
• Camel: The fine down fibre of the Bactrian camel averages around 20 microns in diameter and varies in length from 2.5–12.5 cm. Baby camel hair, which can measure as little as 16 microns (on a par with fine cashmere), is the softest and most prized. Owing to its quality and scarcity, camelhair is used in luxury textiles. The best quality camel yarn is spun on drop spindles by women in nomadic households of Mongolia and Inner Mongolia, China.
• Cashmere: US standards set an average fibre diameter for cashmere of no more than 19 microns, and top quality fibre is just 14. It has natural crimp, allowing it to be spun into fine, lightweight fabrics. Cashmere has small air spaces between the fibres, which makes it warm without weight, while thin cuticle cells on the fibre surface make it smooth and lustrous. Its luxurious, rare and expensive: the wool of six Kashmir goats is enough to make just one cashmere sports jacket.
• Mohair: Light and insulating, its tensile strength is significantly higher than that of merino wool. Like wool, mohair has surface scales, but they are thinner, making it smooth to the touch. Light reflected from the surface gives mohair a characteristic lustre. Thin surface scales make mohair smooth to touch, while light reflected from its surface gives it a characteristic lustre.
• Silk: It is a continuous thread of great tensile strength measuring from 500–1500m in length, with a diameter of 10–13 microns. In woven silk, the fibre’s triangular structure acts as a prism that refracts light, giving silk cloth its highly prized “natural shimmer.” It has good absorbency, low conductivity and dyes easily. Developed in ancient China, where its use was reserved for royalty, silk remains the “queen of fabrics.”
• Wool: It has a natural crimpiness and scale patterns that make it easy to spin. Fabrics made from wool have greater bulk than other textiles, provide better insulation and are resilient, elastic and durable. Fibre diameter ranges from 16 microns in superfine merino wool (similar to cashmere) to more than 40 microns in coarse hairy wools. Limited supply and exceptional characteristics have made wool the world’s premier textile fibre.

Source: Food and Agricultural Organization (FAO)