Materials through the ages: All dressed up - technical fabrics
Maria Felice examines the huge range of materials that have been used in clothing over the years.
There is no such thing as bad weather, only inappropriate clothing – perhaps a frustrating truism when you’re cold and wet, but increasingly true as developments in technical fabrics gather pace.
The first materials that were used to keep people warm came from animals and birds. Using animal pelts to keep warm dates back to the time of the Neanderthals, and likewise the use of leather for clothing and shelter is millennia-old. But for as long as humans have been using animal products, they have been developing processes to refine and enhance them, for example tanning leather to prevent it becoming stiff in cold weather and rotting in the heat.
Until relatively recently, the insulating properties of materials such as down feathers had not been bettered, and its popularity as a filling for coats and duvets remained high. However, down is increasingly controversial due to the practice of plucking live birds that is often, although not always, carried out to obtain the feathers. Less contentious is the use of wool, a popular material for clothing for at least 5,000 years, although before the introduction of shears during the Iron Age, it was plucked out by hand or using bronze combs. Even with the introduction of cotton to Western wardrobes, wool has remained popular for its excellent insulation properties even when wet.
The advent in the 1700s of a flyer-and-bobbin system that enabled yarn to be drawn to a more even thickness, coupled with a machine that revolutionised sheep shearing, reduced the time and cost of producing woollen clothing and increased repeatability and quality.
In recent years, modern synthetic fibres, including nylon and polyester, have outstripped their natural counterparts. Nylon is the generic name for a group of polymers known as polyamides, which were first produced in the 1930s and began to be used in clothing a decade later. Polyester, developed around the same time, is a polymer with the ester functional group in its main chain. Textured polyester fibres are often used to fill quilted jackets with no risk of allergic reactions, unlike down feathers.
While natural wool provides excellent insulation, the search for a modern alternative that is lighter in weight led to the development of fabrics such as polar fleece, made of soft, insulating synthetic fabric, often polyester. Polar fleece was developed in 1979 by Malden Mills, now Polartec LLC. Unlike wool, fleece does not absorb moisture, however it is quite flammable and so must be treated with a flame retardant.
Thinsulate, developed by 3M, was first sold in 1979 and is made from a new type of narrower polyester fibre that is 15 micrometres in diameter. The weave of the fabric facilitates evaporation of moisture and makes the material more effective at insulating, because fibres can be packed closer together. The manufacturer claims that for the same thickness of material, Thinsulate is up to twice as insulating as duck down. The material is being used in the fabric roof of the new Porsche Boxster to reduce heat loss and noise levels inside the car. The development of superfine yarns has continued, and Japanese clothing retailer Uniqlo launched its Heattech range in 2003 to great industry acclaim. Each yarn is made up of many microacrylic fibres, each one tenth the diameter of a human hair. The material adsorbs moisture that is dissipated by the body and subsequently turns it into heat, which the yarn retains.
An addition to the wealth of high-tech garments has been silver threads – the silver reflects up to 95% of body heat, making it perfect for use in gloves for people suffering from poor circulation. It brings an added benefit of being naturally antibacterial, too. The silver nanoparticles inhibit bacterial growth by participating in chemical reactions with cell components that inactivate essential proteins and enzymes.
Keeping warm when temperatures are low is nothing new, but the idea of heat-retaining clothing for use when the ambient temperature is higher is a relatively new development. A collaboration between British Cycling, the University of Loughborough, UK and Adidas has produced a range of clothing that was worn by members of the 2012 British Olympic cycling team between their warm-up and race. The padded trousers are fitted with heating filaments that sit over core muscle groups to maintain their temperature between warm-up and the start of an event. The concept is similar to warmers used in Formula 1 racing to keep tyres at the optimum temperature for racing before the race begins.
As demands placed on specialist clothing continue to increase, science and engineering will continue to contribute more to its development – who knows what garment will be next to step out of the lab and onto a sportsman.