Bamboo is one of the fastest-growing
plants in the world, with some growing 91cm a day, which makes it a highly
renewable resource - it absorbs more carbon dioxide and releases more oxygen
than trees, and the root will continue to grow without the need for
re-planting, all of which makes it great for the environment.
Bamboo is actually a grass, and once
fully grown, some of the larger species can look like trees with a thick trunk
and are much more sustainable than hardwood trees.
Strength
It’s incredibly strong, which is why it
is used for making many products from flooring to furniture, skateboards to
snowboards - even bulletproof vests, and reusable items such as coffee cups,
straws and plates, and recently different technologies have been developed for
bamboo fibre to be used for textiles, including bed sheets and blankets, and
fashion items such as clothing, underwear and socks.
Clothing! But wait! Before you run off
to restock your wardrobe, there are a few things to consider. Most bamboo is
grown in China, and there is limited information regarding how intensively
bamboo is being harvested, or what sort of land clearance might be underway in
order to make way for bamboo. Also, although bamboo doesn’t need pesticides,
there is no guarantee that they are not being used to maximise output.
Production Processes
One production process includes crushing
the woody part of the plant and applying natural enzymes to create a mushy
mass. The natural fibres are then mechanically combed out and spun into yarn.
The result has a similar feel to linen, but very little bamboo material is
produced this way since it’s labour intensive and expensive.
Most bamboo fabric is created through a
chemical process very similar to the production of rayon from wood or cotton.
While there are a number of ways to chemically create rayon, the most common is
the viscose process, where leaves and shoots are essentially cooked in strong
chemical solvents such as sodium hydroxide and carbon disulfide, both being
highly toxic and risky for human health.
Once cooked, the resulting liquid is
pushed through tiny holes (a spinnerette) directly into a chemical bath of
sulfuric acid (dangerous again) where it hardens into fine strands.
After being washed and bleached these
strands form rayon yarn which can be dyed and woven into a soft silky fabric
correctly referred to as ‘rayon from bamboo’. This is lyocell, a semi-synthetic
fabric that is commonly used as a substitute for cotton or silk, and a form of
rayon, composed of cellulose derived from wood.
This is where the sustainability of
bamboo gets a little….iffy.
Bamboo rayon is most commonly made
through the latter process. About 50% of hazardous waste from rayon production
cannot be recaptured and reused, but that doesn’t mean they are being dumped
directly into the environment.
If not correctly managed, these
chemicals pose a risk to workers’ health, with sodium hydroxide causing
irritation to the skin and eyes while carbon disulfide and sulfuric acid have
been linked to neural disorders and respiratory problems respectively.
Similarly, poor management of waste can
cause serious damage to the surrounding environment, but thankfully,
manufacturers in the last three years have been made to revamp their practices
and there has been a great deal of improvement in chemical management and waste
treatment.
The good news is that some facilities
have started using more benign technologies to chemically manufacture bamboo
fibres. As well as using less toxic chemicals, it can be processed in a ‘closed
loop’ system whereby 99.5% of the chemicals are captured and recycled.
The lyocell process is also used to
manufacture TENCEL®, a natural fibre made from wood pulp – usually from
eucalyptus, beech, birch and spruce trees. You’ll have seen it used in a myriad
of sustainable fashion items and in many high street brands.
The downsides are shrinkage - bamboo
fabric tends to shrink at a faster rate than cotton, and the cost - bamboo
fabric tends to be more expensive than either rayon or cotton.
Finally, we know that pandas love to eat
bamboo, but I think there might just be enough to go round!
Marilyn writes regularly for The Portugal News, and has lived in the Algarve for some years. A dog-lover, she has lived in Ireland, UK, Bermuda and the Isle of Man.