The truth about Polyester
Polyester is a synthetic fibre derived from petroleum based products. Polyester fibres are formed via a chemical reaction between an acid and alcohol. The material is used extensively in clothing.
Polyester (polyethylene terephthalate) pellets or chips are synthesized from petroleum-based products. Polyester is thermoplastic, meaning it can be melted and reformed. These pellets are melted and the melted polymer is forced through small holes (spinnerettes). On the exit side of the spinnerettes, the continuous filaments (fibers) solidify. The size and shape of the hole dictates the shape and diameter of the fibers. The fibers are solid polymer; there are no void spaces inside the fibers. These continuous filaments—called “tow”—can be cut to any length (no length distribution, all fibers have the same length) to produce staple fibers for use in textiles and nonwovens, or they can be left as a continuous monofilament, which resembles fishing line.
Being a fiber derived from oil, polyester is water-repellent, and therefore not absorbent. The moisture regain is only 0.4% at standard temperature and humidity conditions. For this reason polyester fabrics do not absorb sweat and can give one a moist, warm, clammy feel. Polyester fibers typically have a low level of wicking, and strength can vary greatly because it can be controlled by how much drawing (stretching) occurs during production. It can go from 2.5 grams/denier to 9.5 grams/denier. These strengths are considered moderate to very high. Higher fiber strengths will produce stronger fabrics. Since it is produced from petroleum, polyester is not considered sustainable and it is not biodegradable.
Is polyester toxic when burned?
When polyester is burned it produces carbon dioxide, carbon monoxide, and water, just like if you were burning a cellulose product. So, while CO2 and CO can both be fatal in concentrations, the fumes are no more dangerous than an ordinary wood fire. However, polyester melts at fairly low temperatures; when polyester garments are ignited they will cling to the skin and severely complicate and exacerbate burns and their treatment. For this reason clothing such as Under Armour, that is otherwise highly regarded for its perspiration-wicking properties, has been banned by the Forest Service and the Marines.
What is polyester?
Polyester is a category of polymers which contain the ester functional group in their main chain. However, the term "polyester" as a specific material most commonly refers to polyethylene terephthalate (PET), which can be made in two ways, and both are done in chambers that feature strong vacuums and high temperatures. The first requires dimethyl terephthalate and ethylene glycol. You make it this way, and the process will liberate methanol--which you have to capture, store and figure out something to do with. (In most cases, the "something to do with it" is to mix it with terephthalic acid and feed it back into the process.) The other is to use terephthalic acid and ethylene glycol. This requires more heat, but it produces no methanol--a very important thing when you consider how dangerous methanol is. No one wants it around if they're not using it. Some polyesters also include naturally-occurring chemicals, such as in the cutin of plant cuticles, as well as synthetics such as polycarbonate and polybutyrate.
An average 6kg wash load could release an estimated 137,951 polycotton fibres from blended fabrics, 496,030 polyester fibres and 728,789 acrylic fibres. These fibres add to the general microplastics pollution as they are too small to be caught by washing machine filters and therefore flow into sewage and end up in the sea. This then endagers sea life and if eaten by human consumed fish could potential cause damage to humans.
Polycotton is a blend of both polyester and cotton. The ratio varies but one of the most common blends is 65% cotton 35% polyester. 50% blends are also quite common.
What is polycotton?
Environmental implications of synthetic fibres
Recent studies have shown the shocking extent of plastics in the world’s oceans and lakes. If microscopic plastic is in oceans, lakes, and rivers, is it in drinking water as well?
Microplastics have been shown to absorb toxic chemicals linked to cancer and other illnesses, and then release them when consumed by fish and mammals.
If plastic fibers are in your water, experts say they’re surely in your food as well — baby formula, pasta, soups, and sauces, whether from the kitchen or the grocery.