Bamboo has been heavily publicised by manufacturers as being the ultimate in green fibre. Is this true or are we being bamboozled? I wanted to know how a bamboo T-shirt came to be. The following information is not a complete account, but hopefully covers enough ground to give you a rough idea.
The commercial growing of bamboo has the potential to be quite an eco-friendly process. As with all forms of commercial farming, profit often overides environmental issues. Harvesting wild bamboo in sustainable quantities would ensure minimal impact on the environment, but would sadly not satisfy the world's demand.
With commercial growing operations there is the real fear of clearing vast swaths of diverse wildlife and replacing it all with just the one plant type. Although bamboo grows well without chemical assistance, one would find it hard to believe that all producers resist the temptation of boosting production.
Most of the bamboo used to make clothing is grown in mainland China and bought up by Hebei Jigao Chemical Fiber Company. They hold the patent on the most widely used process for turning bamboo into fabric.
Modern bamboo yarn is a regenerated cellulose fibre. The fibres may be derived from bamboo pulp, but they have not been made from natural bamboo fibres and are, in fact, rayon fibres made through a chemical process. Bamboo fabrics, for the most part, are synthesised fibres and should really be labelled rayon or viscose. There is a mechanical process for extracting the fibres and producing yarn, but this is more labour intensive, therefore expensive, resulting in a fabric unlike the soft bamboo you would have likely experienced.
For the chemical process, the crushed bamboo is cooked with the help of Sodium hydroxide in to a cellulose fibre liquid and then pressed to remove any excess sodium hydroxide solution. Carbon disulfide is added to sulfurize the compound and cause it to jell. Sodium hydroxide is again added to create a viscose solution. The solution is then forced through tiny spinneret nozzles into a larger container of diluted sulfuric acid which hardens the viscose bamboo cellulose, creating tiny threads that can then be spun into regenrated bamboo fibre yarns.
The heavy processing of bamboo cellulose into fibre "can" be cleaner than that of conventional viscose if a closed loop process captures and reclaims all the solvents used in the process, unfortunately this is not standard practice.
The mechanical process involves machines crushing the woody parts of the bamboo plant and then broken down into a mushy mass with the aid of natural enzymes. The individual fibres are then combed out and spun into yarn. This is similar to the process used to make linen.
The mechanical process is much less popular than chemical processing primarily because it is much more labour intensive and costly. If your T-shirt were processed in this way, I am sure the manufacturer would be advertising the fact to boast less harmful processing and to justify why it is comparitively more expensive.
Dyeing The Bamboo
A large amount of industrial water pollution is due to textile dyeing and treatment. Most often, it is the conventional petrochemical dyes from exhausted dyebaths that take a heavy toll on our waterways. Undyed clothes are unquestionably better for the environment. If the idea of a totally off-white wardrobe isn't for you, then perhaps it is time to explore the vast range of botanical dyestuffs.
If your bamboo T-shirt's label doesn't boast a natural dye, then the chances are it is almost certainly a chemical colour. Chemical dyes are cheaper, easier to use and offer a wider range of colours that can be repeated and matched time after time.
The main problem for the consumer is lack of information that allows them to make an informed decision. Of course, manufacturers only like to tell us the good things about their products. Law doesn't require labels to state ingredients used in the production process or even what processes are undertaken.
Consumers may be paying more for garments on the assumption that the garments have environmentally friendly qualities. As "going green" becomes ever more important, it is vital that there is adequate access to all the facts as opposed to being "Greenwashed!"