rayon vs cotton - which is the best, most sustainable fiber?

rayon vs cotton which fiber is best? more sustainable?

Whenever I start consulting with a new client one of the first things we talk about is what types of fibers they are using and how they can do better. So, when deciding between rayon vs cotton, what's better?

This article covers...

I want to start this article by saying there is no perfect holy grail fiber. Every fiber has its pros and cons. While some are clearly more environmentally friendly than others, that does not mean that they are superior on every metric. While hemp is really easy to grow and has a relatively small environmental impact, it makes absolutely horrible swimwear. That is unless you finish it with a ton of chemicals, which isn't eco-friendly at all… So, I am starting these fibers smackdown series comparing all the pros and cons of different fibers. The goal of the article is to educate you in all of the differences between rayon vs cotton to help you make the best decision about which is the right choice for you.

The inspiration for this post came from the amount of false news out there about fibers. So here you go, coming straight from someone with a college degree in textiles, and 10 years of experience in fiber and fabric development.

To determine which fiber and fabrics are best in this rayon vs cotton fabric debate, we will look at three main categories. They are:

  1. manufacturing
  2. performance
  3. end life

category one - Manufacturing

First, what is rayon?

Rayon is a blanket term for regenerated fibers. Viscose, eco-friendly modal and Tencel, bamboo, and other man-made plant-based fibers are all considered rayons. Basically, any new innovative fiber that is made from a plant is basically a type of rayon.

Cactus fibers, lotus fibers, banana "silk" fibers, the guys making fibers our of seaweed. They are all rayon, and basically kind of just greenwashing since none of them will really open up about what chemicals they are using to make them.

Generally, rayons get their name after the processes used to create the fibers, or the plants used to make it. For examples viscose, is actually a fiber manufacturing system, Tencel, whose generic name is lyocell is made using the lyocell method. Bamboo rayon can be made using the non-eco friendly viscose technique or the eco-friendly Tencel technique. I know, it's confusing. And, brands marketing teams are definitely taking advantage of that to sell you greenwashed fibers.

Because of this, it is basically impossible to say all rayon is better or worse than cotton.

The different types of rayon

So, before we can determine if rayon is better than cotton, first we need to rank all the different types of rayons. For the sake of this article, and understanding the differences let's rank different rayons as follows from least eco-friendly to most eco-friendly.

  • Viscose
  • Rayon viscose made from fast-growing resources like bamboo and eucalyptus
  • Viscose made from reclaimed cellulosic sources like recycled textiles or agricultural waste
  • Modal
  • Tencel/lyocell
  • Lyocell made from fast-growing resources like bamboo and eucalyptus
  • Lyocell made from reclaimed cellulosic sources like recycled textiles or agricultural waste

wait, what is a regenerated fiber?

If you are into sustainable fashion and textiles you have probably heard of regenerated fibres. And, thanks to mainstream media you probably are thinking that regenerated fibers are eco-friendly.

Nope.

Regenerative fibers are basically the greenwashing way to say rayon.

Any type of rayon is considered a regenerative fiber. The definition of regenerative fibers is any fiber that is made from the liquefication of wood pulp. So all of those fancy fabrics that will save us made of seaweed, banana waste, you name it, they are basic "regenerative" rayons.

rayon vs cotton seaweed rayon

Is rayon a natural fiber?

No. There is no such thing as a rayon plant. Rayon fibers are not natural fibers. They are made by humans.

I think where a lot of the confusion originates is that technically rayon is not considered a synthetic material like polyester or acrylic. It is considered a semi-synthetic since because it is made out of natural ingredients. But, this has created a slippery slope for clever marketers.

Many people believe that because rayons derive from wood that makes them natural. No. To make rayon, extremely toxic chemicals, and chemistry are needed in order to break down the wood pulp and then transform that wood pulp into a rayon fiber.

Remember just because something uses something from nature, that does not mean the end product is natural. Cough, cough, high fructose corn syrup.

If rayon is not natural, how do you make it?

Let's first take a look at the viscose rayon process.

  1. First, we start with wood pulp and steep it in a caustic soda solution of sodium hydroxide. During the steeping processes, the wood pulp becomes an alkali cellulose pulp. No, the mix doesn't look like pulp orange juice. Each piece of wood is actually about 2 feet square.
  2. Next, the alkali pulp is shredded down even more into tiny crumbs.
  3. The crumbs are then aged for up to three days. During this time a chemical process happens between the alkali cellulose and oxygen in the air. What is happening, is the polymer chain is decreasing from a high degree of polymerization to a lower dp.
  4. After aging, the crumbs are mixed with carbon disulfide. During this process, the pulp changes from whiteish to bright orange cellulose xanthate.
  5. Next, the bright orange xanthate crumbs are dissolved in sodium hydroxide which forms a honey-colored viscous. This is where viscose gets its name.
  6. Again the mix is aged. As time goes by the viscous will coagulate - which is just a sciency way of saying thicken.
  7. When the viscous is thick enough it is deaerated (science term for the air needs to be removed).
  8. Finally, the solution is ready to be extruded through a spinnerette and into an acid bath of sulfuric acid, sodium sulfate, glucose, and zinc sulfate. In the acid bath, the solution is regenerated (that's where that greenwashed term comes from) back into cellulose fiber aka rayon.

That's a lot of science, chemicals, and steps. I think now that you understand the viscose rayon process you would agree it's not natural at all!

rayon false facts

So, what other false facts are there about rayon?

A lot of journalists will tell you that rayon is so toxic it has been banned from production in the United States. Well, that is only 1/2 true. Curpromonioum rayon aka cupro (the kind of rayon made from cotton waste) was banned in 1975. Production for Lyocell and some types of viscose rayon still happens in the United States.

What is cotton?

rayon vs cotton what is cotton

Cotton comes from the seed of a plant. Cotton plants tend to like hot climates. That is why most of America's cotton production happens in the south, where it is hot. And globally, a ton of production happens in India.

Today, China is the number one producer of cotton, followed by India.

Is cotton a natural fiber?

Yes. Cotton is grown from a plant. It naturally occurs in nature, unlike rayon.

Is cotton better because it is natural and rayon is not?

Maybe not.

Chemicals are still used...

Just because cotton is a natural fiber, that does not mean that chemicals are not used in the process. Chemicals are actually used throughout the entire cotton value chain. From planting the cotton seeds with fertilizers to dousing them with heavy amounts of herbicides and pesticides to ensure fruitful crop season to the final finishing processes, your cotton shirt is full of chemicals.

Organic and regenerative (not regenerated) methods are better

Organic cotton, like organic food, promises not to use chemicals in its production. Regenerative farming is a holistic farming method that treats a farm as an eco-system. You can kind of think of it like zero-waste farming, where plants, animals, and people all work in synergy together.

Remember, regenerated, is just a fancy way of saying rayon.

regenerative vs regenerated

Side note -

How confusing are the terms regenerative and regenerated? They literally are basically exactly the same but mean two totally different things. One is eco-friendly, and the other is far from it. Sometimes I feel like the fashion industry people come up with these terms specifically to confuse everyone.

And none of this is to be confused with recycled synthetic fibers like polyester and nylon.

cotton produces a lot of waste

Cotton also produces a lot of waste. The cotton fibers are inside a cotton seed, that is on a cotton plant. The fibers make up a very very small percent of the entire plant which is basically destroyed during the picking process.

But, why is this a problem?

Well, it wasn't always. Back in the day cotton used to be picked by hand. Actually in many parts of India and developing countries cotton is still picked by hand. But, to increase productivity, cotton picking tractors are now used to pick cotton. The machine pickers destroy the entire cotton plant in the process of picking the cotton pods. So, instead of many harvests, there can only be one quick and wasteful one.

Where do the leftover parts of the cotton plant go?

Some of the cotton plants go to feed livestock. Let's think about this for a second. A few years ago I wrote about the loophole that allows the toxin drenched cotton to be fed to livestock, which humans eventually eat. And, in 2018, a new type of cotton seed was invented that is considered safe for humans to eat.

Secret cotton seeds in your food

Traditionally in India food was cooked with ghee, a type of clarified butter. Then, cheaper vegetable oil started to be used. Now, when I visit the villages most people are using cottonseed oil. I don't trust it. Even if you aren't specifically eating cotton seeds, your food could still be cooked in the toxic stuff without you knowing.

cotton waste as fabric

The other option for cotton waste is to make it into the regenerated fiber cupro. Cupro is a type of rayon specifically made from cotton waste. It kind of feels like modal, but is a little shinier and tends to be weaker. It was originally invented and used as a replacement for silk linings in jackets.

So let that sink in, even if you are buying only cotton garments, you are still, indirectly, supporting the rayon industry.

cotton also uses a lot of water

Cotton is a thirsty crop. But, a lot of the water that cotton uses is rainwater. The media amazes me because they always seem to leave that part out. We see headlines like, cotton is so thirsty that each cotton shirt uses 100 swimming pools of water - or some other type of hyped-up headline like that. But, how much of that water is rainwater? I think it's important to remember that water was not taken from reservoirs.

I am not saying that farms do not irrigate water, all I am saying here is some water naturally falls from the sky. And, no one seems to know exactly how much.

Direct evidence of this, is when there are dry seasons, cotton crops fail, and cotton prices increase because of scarcity.

So, yes. Cotton is natural and rayon is not. But, as you can see in their production methods both have not so "natural" manufacturing processes.

category two - performance and fabric characteristics

Ok, so it's hard to determine which fibers manufacturing process is the best. What about the fiber characteristics? Is one fiber superior to the others that will create a better product that lasts longer?

We will rank the fibers on four characteristics

  1. durability
  2. comfort
  3. appearance
  4. home care

scoring
all properties are scored on a four-point scale

  • excellent
  • good
  • fair
  • poor

1 - durability

rayon vs cotton - abrasion resistance

Abrasion resistance is the material's ability to not break down from rubbing. This is an important attribute for places like between the leg on pants and under armpits on shirts where there could be a lot of rubbing and friction. If you want your product to not wear out and get holes, you want a fabric with good abrasion resistance. So how do the fibers rank?

  • cotton - good
  • viscose rayon - fair
  • lyocell rayon - fair

conclusion - cotton has a slightly better abrasion resistance

rayon vs cotton - strength

How strong is the fabric? This measure relates to how much force is necessary to break the fibers.

  • cotton - good
  • viscose rayon -poor to good depending
  • lyocell rayon - good

Poor to good, what does that mean? There are different qualities of rayon that are dependent on the chemistry and aging time while the fibers are being manufactured.

But as a general rule, cotton and rayons will have around the same strength.

rayon vs cotton - strength loss when wet aka wet strength

Generally, when fibers become wet, they become weaker. Just how much weaker though?

  • cotton - +10 percent, cotton is actually stronger when wet
  • viscose rayon - 30-50% weaker
  • lyocell rayon - 11% weaker

Why is this information important? If you are designing work out gear or swim gear that will become wet cotton is a better choice over rayon. Also, wet strength is an indicator of how much your clothes will wear out in the wash.

conclusion - cotton is the best as it becomes stronger when wet, followed by lyocell, and then viscose

2 - comfort

rayon vs cotton - absorbancy

Absorbancy is the fiber's ability to absorb water, both from the air and when submerged, like in laundering or swimming. As a general rule hydrophilic fibers like water and are good at absorbing. Good absorbancy in a fiber creates a more comfortable fabric that leaves you feeling cool instead of clammy, and is considered a breathable fiber. And, fibers with high absorbency also tend to have lower rates of static cling.

  • cotton - 8%
  • viscose rayon - 11%
  • lyocell rayon - 11%

conclusion - cotton and viscose and lyocell rayon are about even when it comes to absorbancy. For some reason, I get a lot of people asking me which fiber is more breathable cotton or rayon? For the most part, people seem to think that cotton is more breathable, probably thanks to Cotton Inc's heavy marketing on the fabric of our lives. In reality, when it comes to breathability, there is not much difference.

rayon vs cotton - flexibility

The more flexible a fabric is the more fluid and drapey it is. For example, think of a silk dress and a heavy winter wool sweater. The silk dress has more flow.

  • cotton - fair
  • viscose rayon - good
  • lyocell rayon - fair

conclusion - I would even say some new viscose rayons are excellent. The other week I got a delivery off rayon fabric swatches from a mill and they were really really hard to tell apart from silk. As technology gets better, so are the fabrics.

But, is excellent flexibility always good?

No. In some cases like in men's button-down work shirts, we want crisp structured cotton. Flowy silk is not always better for design. It is important to take into account what you are designing and then what fiber will help to make the best product for that specific style.

Lyocell and Tencel were specifically designed to mimic the look, feel, and technical qualities of cotton.

rayon vs cotton - elasticity

Elasticity is the ratio between stretch and recovery. How much can a fiber stretch, and then, return back to the original size? This is important because we don't want our clothes to stretch out over time.

  • cotton - poor
  • viscose rayon - fair
  • lyocell rayon - good

conclusion - cotton does not have much stretch, while viscose rayon has the most.

Generally, for the sake of comfort, we want a little bit of stretch in our clothes. But, again, depending on the design, the stretch is not always a good thing. Like in the example of raw denim jeans. We want a sturdy rigid fabric.

rayon vs cotton - hand

The hand of a fabric is very subjective, it is a description of how a fabric feels, literally in your hands.

In my opinion, there is no real ranking system for this. It is totally up to the person touching the fabric.

3- appearance

rayon vs cotton - resiliency

Can the fabric spring back after being crushed? You probably noticed this while packing for vacations. Why do some garments come out totally wrinkly and some look just as great as when you packed them? A general rule is that knits always have better resiliency than woven fabrics.

  • cotton - poor
  • viscose rayon - poor
  • lyocell rayon - fair

conclusion - rayons actually behave like cotton in a lot of ways. And, this is evident in resiliency. While lyocell is a little less prone to wrinkles, if you are planning on packing a suitcase none of these options are fibers you would want to bring with you. Unfortunately, polyester is one of the most wrinkle-resistant fibers out there.

rayon vs cotton - pilling resistance

Pills are those little balls of fibers and fuzz that form on the top of fabrics. Usually, fabrics with higher static electricity and low moisture absorbency (hydrophobic) tend to pill more easily.

  • cotton - good
  • viscose rayon - good
  • lyocell rayon - good

conclusion - all of these fibers are able to resist pilling, this is because they are also good at absorbing moisture.

4 - home care

rayon vs cotton- mildew resistance

  • cotton - poor
  • viscose rayon - fair
  • lyocell rayon - fair

conclusion - Cotton is actually one of the most prone fibers to mildew in the world. This is because it is so great at absorbing moisture. While viscose and lyocell rayons are a little less likely to grow mildew they are not far behind cotton's poor performance.

For me in India mildew resistance is super important. During half the year it rains every day, and mildew and mold become a real problem. For that reason, I prefer silks which are more mildew resistant. And, acetate also does better in wet climates.

rayon vs cotton - ironing
  • cotton - 400
  • viscose rayon - 350
  • lyocell rayon - 400

conclusion - all three fabrics you can get pretty hot without damaging.

rayon vs cotton wash vs dry clean

Cotton, viscose rayon, and lyocell rayon can all be laundered at home in a standard washing machine and dryer. Dry cleaning is not necessary for any of these fibers, which is nice because that amounts to fewer chemicals going into the garment's entire lifecycle.

rayon vs cotton - sunlight resistance
  • cotton - fair
  • viscose rayon - fair
  • lyocell rayon - good

conclusion - viscose rayon will hold up a little better in the sunlight and UV rays. While this might not be an important metric for someone living in, say, Alaska, resistance to sunlight is important for people living in hot sunny climates that want their clothes to last.

So, which garment performs the best? And, will make the best product.

Well, I kind of fooled you. I think that depends on what type of product you are making. Each fiber has different pros and cons.

category three - What about the end-life?

What happens to rayon and cotton when we are done using them?

If it's hard to determine whether rayon vs cotton is more natural or has better performance, what about the afterlife of the garment? Do they biodegrade?

Which fiber is biodegradable, rayon or cotton?

Both fibers are biodegradable! And, a recent study just proved that rayon might actually biodegrade quicker than cotton!

But, it is important to remember what these fabrics will biodegrade into. if they are soaked in toxic dyes, and textiles finishes, do we really want them to biodegrade into our soil?

Which is more sustainable? Rayon or cotton?

Neither. Each fabric has its own set of pros and cons. It's as simple as that. When deciding what fabric is right for you to use in your clothing line, or even to buy for your closet, there are A LOT of different considerations to take. Maybe resistance to mildew is your number one priority, like for me in Goa. Or, maybe, you care more about the chemicals that go into making the product. Everyone has a different prerogative, and IMO there is no right answer to the great debate about rayon vs cotton.

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