I remember when I was little I always used to flip around my shirt and read the tag when on car rides. I think I enjoyed the act of defiance in cultural norms of t-shirt wearing than I did the actual information on the tag. While all the tags would have a wide range of instructions for washing and brands, almost all the tags would say the shirt was made with polyester or cotton. I never really understood the difference between the two when I was younger and didn't really care to know. It was't until recently when I picked up sewing that I decided to learn what the difference was.
Cotton is a plant based material that is harvested and goes through a set of processes of bleaching and dyeing in order to become fabric for clothing.. Polyester a made from a reaction of coal, petroleum and water that goes through a process of bleaching and dyeing in order to become fabric for clothing. It may seem easy to pick the more ethical once reading those two simplified descriptions, but there is more grey area than one would expect. While both options have experience the negative effect of bleaching and dyeing, they both have positives and negatives.
While Cotton does come from a sustainable resource, its production is far from environmentally friendly. With cotton crops requiring approximately 20,000 litres of water to produce 1 kg of cotton and making up 24% of the worlds and insecticides pesticides purchases, its far from clean(1). These chemicals used are known to leak into surrounding water sources and harm ecosystems. Due to these negative impacts, many have started looking to organic cotton for clothing as it has less impact on the environment.
Despite cottons impact going into the market being harmful, it leaves on a positive note. Cotton is one of the most biodegradable materials you can buy for clothing. Although this is positive, it does have a drawback. Because this material can degrade easily, it has a shorter lifespan as a shirt before it become unwearable by the users standards (2). While I do think most people do throw out shirts way before they should be, cotton still suffers in this aspect.
When comparing to cotton, the production of polyester is immediately known to have a negative impact on the environment. Using coal and petroleum is unsustainable for the environment and also producing harmful chemicals into the atmosphere in their extraction. With polyester creating approximately 9.52 Kg of CO2 emissions per ton of fibre compared to cottons 5.89 Kg, it's easy to see how it impacts the environment (3).
While polyester is considered non-biodegradable, it is recyclable. Some of the plastic bottles being used now are made from old shirts and vise versa. Some is even recycled into fleece and more material to be used in other clothes. Along with its ability to be recycled, polyester tends to have a longer life as it degrades less when being worn when compared to cotton.
When it comes to buying a new shirt after reading some of the information provided, it can be a difficult moral choice. Both have their own set of positives and negatives that can dissuade one from purchasing them. While I did not set out to persuade a reader from buying one of the other, I did hope to inform you of the processes used in their making and hopefully spark some of your own research into the making of different materials as well.