When we think about our laundry, it often involves a warm, cozy house and sunshine on a Sunday afternoon. But what about when the mercury drops to -20°F or you have that sudden urge to do your laundry in a hot spring? What happens to our clothes and fabrics in different temperatures?
Fortunately, the world of textiles is home to many dedicated people who have thought long and hard about this question. A brief perusal through some academic research articles on textile properties in extreme conditions reveals that cotton still remains king of performance even when things get sweaty (or not so sweaty).
The following article summarizes some of what we know about the effects of heat and cold on natural fibers such as cotton.
We’ve all been there – you’re going about a normal day and then, wham, a sudden heatwave. Whether you’re playing host to a wild summer party, or perhaps you’ve left your A/C unit behind on a business trip and are suffering in silence, extreme temperatures are not always as welcome as we’d like them to be.
When it comes to extreme heat, the first thing we need to think about is shrinkage. The majority of textile transformations that we observe in extreme temperatures are due to the processes of shrinkage and/or the process of relaxation.
Cotton is particularly susceptible to shrinkage. In fact, it is the most shrinkable of all the natural fibers. The shrinkage that we see in cotton when exposed to heat is a result of the cellulose in the fibers contracting, which causes the fibers to pull together.
On the other side of the coin, we have extremely cold temperatures. You might be a winter sports enthusiast or a resident of a chilly region. If you fit into either of these categories or have ever done your laundry in a cold environment, you’ll know that extreme cold can be just as challenging as extreme heat is.
One of the most interesting effects of extreme cold on textiles is the process of contraction due to the freezing of the water that is present in all fibers with some exceptions (more on that below). When water freezes, it expands by 9%. This expansion has the effect of causing fibers to contract and fabrics to wrinkle.
Cotton is particularly susceptible to this process of contraction in the extreme cold due to the fact that it is the most hydrophilic of all the natural fibers. What does this mean exactly? It simply means that cotton fibers love water and that, when water freezes, the fibers contract.
What Happens to Cloth in Extreme Temperatures?
Let’s take a look at what happens to the fibers themselves in extreme temperatures. Cotton’s resilience in extreme temperatures when subjected to extreme temperatures, cotton fibers shows an interesting phenomenon called superheating.
This occurs when the temperature rises higher than the boiling point of water but below the melting point of the fiber.
Cotton’s resilience in extreme temperatures is rooted in the fact that its fibers are crystalline in nature. The issue of thermal expansion is related to the fact that when crystalline fibers are heated, they do not expand. On the contrary, they contract.
When the fibers have been heated to the extreme, they may begin to melt. What’s more, the melting point of cotton is relatively high – around 170°C. This means that cotton is able to withstand relatively high temperatures before it starts to break down.
Cotton’s resilience in extreme temperatures
Cotton is a strong and resilient fiber that is able to withstand a very wide range of temperatures. Its thermal resilience is largely due to the fact that it is a natural fiber. Brilliantly, nature has designed cotton fibers to swell and shrink in response to changes in temperature.
When the temperature rises, the fibers absorb water and swell. At high temperatures, the fibers are fully hydrated and the fabrics become softer and more flexible. When the temperature falls, the fibers lose water and shrink. In extreme temperatures, the fabrics become stiffer and less flexible again.
Because of cotton’s thermal resilience, the fabrics are able to withstand high and low temperatures without undergoing major changes in their structure.
Despite the fact that cotton can withstand a wide range of temperatures, it is not suitable for very low temperatures.
Nylon’s resilience in extreme temperatures
Nylon is another widely-used synthetic fiber. It can be found in a huge range of items, from shoes to gardening gloves. When nylon is subjected to high temperatures, it contracts. When it’s low temperatures, it relaxes.
When nylon is heated, the molecules are forced to vibrate at a faster rate. This causes them to collide with each other and generate friction. This, in turn, creates a significant amount of heat.
A phenomenon known as relaxation occurs when nylon is subjected to low temperatures. The molecules in the fibers slow down and stop generating friction.
Nylon is particularly susceptible to being affected by humidity. When humidity is high, it causes nylon fibers to swell. This has a negative impact on the fabric and can lead to wrinkling and even holes developing in the material.
Polyester’s resilience in extreme temperatures
Polyester is one of the most widely used man-made fibers in the world. It’s easy to see why: it is cheap to produce, highly durable, and can be easily spun into different types of fibers – such as filament or yarn.
When subjected to extreme temperatures, polyester fibers resist contracting. They are actually capable of expanding when they are heated up.
The thermal expansion of the fibers is due to a change in the orientation of the molecules in the fiber. They uncoil and straighten out when they are heated, but they coil back up again when they are cooled.
When polyester is subjected to extreme cold, it shrinks. This is due to the molecules in the fibers contracting.
Dark and hot: The effect of darkness on cotton
We’ve all heard the old wives’ tale that you shouldn’t put your light-colored clothing in the washing machine with dark-colored clothing. But why not? When dye molecules are added to textiles, they react with the fibers in the garment and bind to them. It can take a long time for this reaction to occur.
When fabrics are subjected to heat, the dye molecules are pushed out of the fabric and into the water. This can cause fabrics to run (which is why you shouldn’t wash a garment with red wine on it with other items).
When fabrics are washed in very cold water (as is the case with cold water processing), the dye molecules are less likely to be pushed out of the fabric and into the water.
Instead, they may just gradually migrate out of the fabric. This can cause the color of the fabric to fade over time. It is most likely that the dye molecules will migrate out of the fabric when it is dark (which is why you shouldn’t wash dark-colored fabrics with white clothing).
When thinking about extreme temperatures and their impact on our clothes, it’s important to consider the wide range of fabrics that are out there and the different ways that they react to extreme conditions.
Nylon, polyester, and cotton are all commonly used natural fibers that are found in a wide range of garments. As we’ve seen, each of these fibers reacts differently in extreme temperatures.
Cotton is particularly susceptible to shrinkage in extreme temperatures, but it is also able to withstand relatively high temperatures before it begins to break down. Nylon is particularly susceptible to being affected by humidity, while polyester is more likely to resist contracting in extreme temperatures.
It’s important that we understand how our clothing is made and what happens to it in extreme temperatures so that we can best care for it and get the most wear out of it.