sustainability ·Aug 18, 2020

Bamboo - The Most Sustainable Material?

Why Bamboo?

Over the past few years Bamboo has gained increasing attending, deeming it to be ‘the most sustainable material’. Why?

Fast growth rates

It has been recorded that some species of bamboo can grow up to 1 metre per day (1), gaining it the title of 'the fastest growing plant on earth'. Unlike an oak tree that can take up to 20 years to reach maturity, bamboo is ready to be harvested after just 4. After harvesting, it doesn’t need to be replanted as it can regrow from its extensive root system.

Carbon Sink

Because of bamboo's accelerated growth rates, it is able to fix large amounts of CO₂from the atmosphere and convert this into 30% more oxygen than an equivalent mass of trees (2). It is therefore great at absorbing greenhouse gases.

Organic

Bamboo is almost always grown organically. Unlike cotton, harmful pesticides are not needed to aid its growth. This not only prevents soil depletion but also it means there are no harmful chemicals in your clothes.

Grows Anywhere
There are over 1,000 species of bamboo. It is able to thrive in a variety of different habitats and is therefore found all over the world (3).

Bamboo as a Textile

A common application for bamboo is as a textile that can be used for clothing, linens and other fabrics. There has been discrepancy as to whether it is truly a sustainable material and this comes down to how it is processed into textiles (4). Heavy, often toxic, chemicals are required to transform the plant into fabric.

There are two ways of processing the plant into fabric (5):

Mechanically – Bamboo Linen

This process involves crushing the woody parts of the bamboo and mixing them with a natural enzyme to break down the walls, allowing it to be spun down into yarn. The result of this is a thicker fabric often referred to as ‘bamboo linen’. It is both expensive and labour intensive to produce this linen and the resulting fabric is not particularly soft.

Chemically – Bamboo Rayon

This is the most popular method of bamboo processing as the resulting fabric is much softer. Chemically manufactured bamboo is often called ‘bamboo rayon’ due to the similarities in how it is chemically manufactured, and the soft feel is similar to that of rayon. This is how most bamboo products are manufactured as the end result is much softer than that of bamboo linen.

It is in the chemical manufacturing of bamboo that its sustainability comes into question. Bamboo rayon is made through the viscose process where toxic chemicals, such as sodium hydroxide and carbon disulphide, are used to break down the cellulose in bamboo. This produces a pulpy viscose substance that can then be spun into yarn and turned into fabrics. These chemicals can be harmful to human health and are both linked to cases of tiredness, nerve damage and headaches. It is estimated that around half of the waste from this production process cannot be recaptured and thus is released into the environment.

The Lyocell Process

There are other ways to chemically manufacture bamboo that are less environmentally damaging. The lyocell process, which is used to produce lyocell (TENCELÒ) from Eucalyptus cellulose, can be modified to use bamboo cellulose (6). This is a closed-loop process whereby a non-toxic chemical solution, N-methylmorpholine-N-oxide (amine oxide), is used to break down the cellulose - 99% of this solution can be recaptured and reused. TENCELÒ is becoming more popular and is now being used by some high street brands.

The lyocell process is a much better alternative to traditional chemical processing as the amine oxide is not harmful to human health.

Final Thoughts

Bamboo gains its title as the most sustainable material due to its abilities to fix CO₂from the atmosphere and grow almost anywhere, rapidly. Sadly, most bamboo items on the market are bamboo rayon. Lyocell is a more sustainable alternative with a much less damaging environmental impact but it is difficult to find lyocell products made from bamboo.

References

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