Unexpected Sustainability: Recycled and Biodegradable Polyester and Polyamide
Synthetic fibers, including polyester and polyamide, have a bad name when it comes to sustainability. But even these notoriously environmentally harmful fabrics can be produced in a more thoughtful manner that reduces harm – through recycling and creating versions that are biodegradable.
What are synthetic fibers?
Let’s start at the beginning – what are synthetic fibers anyway?
A synthetic fiber is one that is man-made and doesn’t exist in nature. This is in contrast to natural fibers, like cotton, wool, and linen, which are harvested from natural sources, then spun into yarn.
These man-made fibers are made up of polymers that are created through a chemical reaction called “polymerization” – different polymerization reactions are used to make different fibers. The source materials for forming synthetics vary; examples include coal, oil, natural gas, or liquified cellulose.
Once the polymers have been formed, the liquid solution is filtered. It can then be spun into fibers. The fibers must then be stretched to create a uniform group that can be formed into yarn. This yarn is then woven or knitted into fabric in the same way a natural fiber yarn would be.
Rayon, a cellulose-based material, was the very first synthetic fiber. It was created in 1924 as a cheaper alternative to silk by the DuPont company. However, man-made fibers didn’t really catch on in the mass market until the introduction of synthetic polyamide, also known as nylon, which could be used to make high-quality, durable women’s stockings.
These days, synthetic fibers are everywhere. The most widely used is polyester – it is very common in fast fashion because it’s cheap to produce and extremely versatile.
Polyester vs. Polyamide fabric: what’s the difference?
The two man-made fabrics we will be discussing today are polyester and polyamide.
The names sound very similar, but these two fibers are formed through completely different chemical reactions. Both polyester and polyamide are petroleum-based polymers, but the chemical links holding polyesters together are called ester bonds and those in polyamides are amide bonds.
These two fabrics also have different characteristics. Polyester tends to be more lightweight and is often used in casualwear. Polyamides are more durable and are usually used for hard-wearing garments like outerwear and activewear.
The benefits of polyester and polyamide: why do we use them?
When synthetic fibers were new to the market, the quality of fabrics made from them was much lower than the natural fibers consumers were used to at the time. However, manufacturing methods have come a long way in the years since and both polyester and polyamide have many characteristics that make for great garments.
Both fabrics are very versatile and can be made in a variety of weights, both with and without stretch. In addition, they are both strong and durable – stronger than many natural fibers, though polyamide is tougher than polyester. Another benefit of these fabrics is that they are naturally wrinkle-resistant, making them great for people who travel or for those who just hate ironing.
Polyesters and polyamides are both very comfortable to wear and can be soft and smooth to the touch, depending on the type of fabric. The biggest downside to these fibers when it comes to wearability is that they aren’t breathable and can trap sweat inside the garment and cause a clammy feeling.
The environmental pitfalls of polyester and polyamide
While polyester and polyamide are both quite versatile and comfortable to wear, the production process and the end-product are not very sustainable or environmentally friendly.
Here are a few of the harmful impacts of producing synthetic fibers like polyester and polyamide:
- Many of the chemicals used to create these fabrics are very toxic, which is dangerous for workers producing the fibers and for the environment, especially if they are not contained and disposed of properly. These chemicals can get into the water system, impacting aquatic life.
- Polyamide production in particular, creates nitrous oxide, which is harmful to the ozone layer.
- Crude oil and natural gas must be drilled and pumped from the earth to be used as the base for creating these fibers, which is a pollution-prone process that is removing non-renewable resources from the earth.
- Producing synthetic fibers uses a lot of water and energy.
- Polyester and polyamide are not biodegradable, so when they eventually make their way into landfills and the sea they stay there.
A more sustainable alternative: recycled and biodegradable synthetics
With the increased focus of the fashion industry on sustainability and reducing harm, traditional synthetics are being pushed aside for more environmentally friendly options. These more sustainable alternatives include natural fibers as well as recycled and biodegradable synthetics.
Recycled polyamide and polyester
The process of recycling already-used items to create new products reduces waste and helps keep materials useful and out of the landfills. Both polyester and polyamide can be made from recycled components.
Recycled polyester is made from plastic waste that is broken down and re-processed to create fabric. The used plastic that is the base of recycled polyester typically comes in the form of plastic bottles, either diverting them from the landfill or removing them from the ocean.
We stock a few recycled polyester fabrics made from Newlife™ and Seaqual™ yarn, both of which are created from plastic waste taken out of the sea or from other sources. This Seaqual™ swimwear fabric and this Newlife™ jacket fabric are great examples of beautiful recycled polyesters.
Producing recycled polyester fabric requires less water and energy than virgin polyester and reduces carbon emissions. Plus, recycled polyester has the same quality and wearability as traditional polyester fabric!
Recycled polyamide, on the other hand, is usually made from either fabric waste, industrial fishing nets, or carpets.
Recycled polyamide produces significantly less carbon emissions than virgin polyamide during the production process. It also helps to divert waste from landfills and keep it out of our seas. Fabrics containing recycled polyamide are exactly the same as those made with virgin polyamide – the chemical make-up is the same and the material performs that same way.
Biodegradable polyamide and polyester
Traditionally, polyester and polyamide are not biodegradable fibers. Researchers estimate that polyester would take 300 years to degrade completely. This means that clothing and other products made from these fibers will sit in landfills for hundreds of years without breaking down.
However, new techniques in fiber manufacturing makes biodegradable synthetics a possibility!
Biodegradable polyesters and polyamides can be created by adding organic compounds into the chemical mix used to form the fabric. This addition doesn’t impact the performance of the fabric, but it allows it to be degraded by microbes when discarded.
The decomposition occurs when the fabric is in damp and anaerobic conditions (with no oxygen), like when buried in a landfill – meaning it won’t degrade while sitting in your closet, but it will once you throw it away! Biodegradable polyamide and polyester can decompose in just 3-5 years, a big difference from the 300 years of traditionally-made synthetics!
We stock a range of biodegradable polyamide fabrics as well as biodegradable polyesters, including fabrics made with Yarnaway™ biodegradable yarn. This Yarnaway™ gabardine fabric is both biodegradable and made from recycled materials – it would make a great pair of trousers! This rust-colored biodegradable polyamide fabric would be awesome sewn into a light jacket or men’s swim shorts.
How is it made?
Now that you know what recycled and biodegradable polyester and polyamide are, let’s take a brief look at the processes that are used to create each of these sustainable textiles.
To make recycled polyester, waste plastics are first collected and sorted by color. These plastics are ground up to form small flakes. The plastic flakes are “depolymerized” – or broken down into their base molecule. They can then be re-polymerized and spun into fibers, combined into yarn, and woven or knitted into fabric.
Most recycled polyamide is made by first melting down the source materials. Polyamides melt at a low temperature, so they can be separated out from contaminants by melting them out. Just like with recycled polyester, the fibers are depolymerized so that they can be reformed into new polyamide fibers and made into fabrics.
Biodegradable polyamide and polyester
There are several different ways of producing biodegradable polyester and polyamide, but the most common method is a reaction utilizing diacid or acid anhydride, which are organic compounds that allow the resulting polymers to be biodegradable.
Synthetic fibers created through these methods become biodegradable when exposed to moisture – the polymer matrix expands in a damp environment, allowing microbes to get into the polymers and begin breaking them down. This is in contrast to traditional polyesters and polyamides, where the polymer matrix stays compact and doesn’t allow degradation.