Check the label on the T-shirt you are wearing. How many materials are listed? There is a good chance that the fabric has been woven from a mixture of different fibres, for example cotton and polyester. (The list refers only to the fabric. It does not take into account zips, buttons, the thread used to make it or any prints it may have). This presents one of the biggest challenges for textile recycling.
Currently, less than 1% of the garments produced are recycled to become clothes again. Due to the increasing number of materials and blends in textile composition, it is a challenge to find ways to separate fibres of different origin so that they can be recycled through their respective systems. The problem is especially found in blends of synthetics (such as polyester, elastane and spandex) with natural fibres (such as cotton, viscose and silk).
For reasons of design, functionality and cost, polyester has become the most frequently used fibre. Being petrochemical, it has very different properties from cotton, polyester's usual partner. Jeans are the perfect example. It has gone from being a 100% cotton garment to regularly containing up to 10% elastane. In textiles, percentages as low as 1% elastane make it absurdly difficult to optimise recycling. 87% of the materials used for clothing production end up in landfills or incinerators at the end of their use.
It is possible to recycle the blends by mechanical processes. However, this makes it difficult to control the material composition in the resulting yarns. In addition, the presence of a synthetic fibre in a fabric completely eliminates the biodegradation characteristic. And, in turn, the cellulosic content makes chemical recycling of synthetic fibres impossible.
As a result, mono-materiality is often used as a principle for sustainable design.
Mono-materiality refers to the presence of a single material in the composition of the product. In the case of textiles, being of the same origin is sufficient to facilitate the recycling of a garment in the future. It is key to the circular economy because mixtures of materials make it more difficult to capture the value of the material. The aim is to extend the circulation time of materials by avoiding extracting more resources than can be regenerated, a very important objective within the circular economy.
Text by: Roberta Lebed.