Compostable Polyester Exists. Let's Talk About It
I was scrolling through Vogue Business the other day when I stumbled upon an article by George Arnett about biodegradable lingerie. I thought the topic was interesting. You see, unless you want to wear only simple cotton underwear, there’s not a high chance you’ll find something biodegradable or sustainable in any other way.
Conventional underwear is often made from nylon, polyester, lycra, elastane. Especially when it’s decorated with lace. However, you don’t need a synthetic fiber to make lace. On the contrary, you can actually make lace from organic cotton, too. And not just that. The article introduced me to something called compostable polyester and elastane. WHAT? Let’s dig deeper.
WHAT IS COMPOSTABLE POLYESTER
Biodegradable polymers have been a very interesting topic in the science community in the past two decades. According to Polymer Database, there are two types of biodegradable polymers. “The first class are polymers synthesized from renewable sources, and the other class are synthetic, mostly from mineral oil derived polymers that are biodegradable.”
The production of these polymers is still not widely spread but there are some that have gained commercial use like polylactic acid (PLA), polyglycolic acid (PGA), poly-ε-caprolactone (PCL), polyhydroxybutyrate (PHB), and poly(3-hydroxy valerate). “The most common and most promising bioplastic is polylactic acid. First, corn or other biomaterial is fermented to produce lactic acid, which is then polymerized to polylactic acid (PLA). The demand for PLA is expected to grow from 0.1 Mta today to 2Mta over the next few years.” (Polymer Database) Now, if we assume that corn or other biomaterials are organic, then this sound very promising.
WHY IT’S STILL NOT OKAY TO THROW COMPOSTABLE POLYESTER AWAY
“People ask me ‘If I lie down in the garden, will it start to disappear?’,” said Stephanie Devine, a businesswoman from Australia who developed one of the first bras from compostable polyester, for Vogue Business. That’s funny because when something is compostable, we often think that we can just throw it in the bin and it will degrade naturally within a certain period of time. However, that is not entirely true. In order to be biodegradable, a polymer needs certain conditions.
According to SPHERE Group, those conditions are “physico-chemical (temperature, humidity, pH) and micro-biological (quantity and nature of microorganisms).” This means that compostable polymers need to be put in the so-called industrial compost. To biodegrade they need numerous microorganisms, constant temperature of 50 or 60ºC as well as humidity. (SPHERE Group) For example, Wolford specifies decomposition of their compostable lingerie “begins when products are treated with a natural enzyme in a facility maintained at a temperature of 60 degrees Celsius.” (Vogue Business) So no, your underwear won’t disappear if you lie down in the garden in it.
But where to dispose of your compostable underwear then? You should be able to just dispose of it into your biowaste bin. However, since this is a brand new field, I recommend checking with someone from the waste management infrastructure available in your country.
Cover photo from Wolford Aurora Collection 2019.