If you shop around for bedding and look for luxury, comfort, breathability and environmental sustainability, you will definitely run into Rayon, Viscose, Modal, and Lyocell. This article will take a spin through fabric manufacturing processes and a little chemistry to help you understand the differences between these fabrics. Since this is BestBambooGuide, we’ll pay particular attention to the bamboo versions of each of these that are most commonly used in sheets, pillows, mattresses, and clothing.
All Four of These Fabrics Start Life as Plants
First things first. Rayon and viscose are the same thing: rayon is the term most commonly used in North America, while viscose is the term most commonly used in Europe. Given the global nature of businesses these days, you’re more likely than ever to see either of these terms used in either location, but don’t worry: they are still the exact same thing.
Now, even though these are all “man-made” fabrics, creating these fabrics always starts with a plant. The choice of plant will vary and has a big impact on the environmental sustainability of the material as well as on some of the properties of the fabric (such as its moisture wicking and antimicrobial properties). Of course, at BestBambooGuide we focus on bedding products whose fabric begins life as bamboo, but you should know that these fabrics are not always made from bamboo. All of these: rayon, viscose, modal, or lyocell, are made from a variety of plants including trees, soybeans, cotton, as well as bamboo. Some companies have even tried making these fabrics starting with Eucalyptus trees! (I don’t know how environmentally friendly it is to use a Eucalyptus tree though.)
The main reason these fabrics are all plant-based is that the strength and flexibility of the fabric comes from the cellulose in plants. Cellulose is the compound in plants which gives them their stiffness while still allowing them to be supple enough to survive in nature. The fabrics themselves are then “regenerated cellulose fibers.” This just means the original plants are dissolved and then reformed to make them into a fiber suitable for weaving into fabric. The fibers themselves are then made of these chains of cellulose. This is very similar to the (completely natural) process which produces silk. That’s why these fabrics are often compared to silk in terms of their texture.
The important part here is that although these are all man-made fibers, they are still composed of natural cellulose fibers. This gives them many of the properties you are looking for in bedding and clothing: a natural feel on the skin, breathability, and the ability to pull moisture (in the form of sweat) off your skin effectively. These moisture absorbing properties are confirmed by research. Yvonne Roach and Robert Kay say the following:
The most common absorbent fibre used is cotton, but other fabrics have recently been designed that are more absorbent, such as modal, micro-modal, Tencel®, and other viscose-based fibres. All of these are made from the same base material – plant cellulose – which loves water.
Water (or your sweat) gets absorbed into tiny gaps called micropores inside the fibre.
So while cotton is the most classical natural fiber, used in clothes and bedding for hundreds of years because of its moisture-absorbing properties, the new man-made fabrics of Rayon/Viscose, Lyocell and Modal keep these natural benefits, while embracing a more environmentally friendly approach to production.
Comparison With Synthetic Fabrics Like Nylon and Polyester
The question people often ask is whether viscose and rayon are similar to Nylon and Polyester. In short: no. Nylon and polyester are formed from chemicals that derived from petroleum. While the viscose fabrics we’re talking about for bedding are man-made they are still natural in that they are chemically similar to plants. Nylon and polyester are chemically much closer to plastic, which is also derived from petroleum. Sometimes peole will refer to nylon and polyester as “fully synthetic” to show the difference.
The guys at Robert Owen undershirts in the UK sum up this difference as follows:
Unlike Polyester, Viscose is water absorbing; water is absorbed into tiny micropores in the fibres themselves. This makes Viscose highly breathable, which is crucial for comfort.
Breathable fabrics remove water vapour (and heat) from your skin, leaving you feeling cool, dry and comfortable. Because Viscose does this so well, it is ideal for clothing that is worn all day and for clothing that’s worn next to your skin.
While these chemical differences may seem complicated the big difference is how the fabrics interact with water. Not surprisingly, the fabrics that are chemically similar to plastics tend to repel water. This great for outerwear, backpacks, or anything where you want to keep water out. It is definitely not great for clothing and bedding since it tends to trap the sweat coming off your body. This leaves you feeling hot and sticky: not what you want from your sheets!
On the other hand, fabrics that are made of cellulose tend to absorb moisture. This means the fabric will absorb the moisture off of your skin, and then it will be able to evaporate from the surface of the fabric. This is ideal for clothing and sheets since it helps to keep you cool and dry.
Differences Between Viscose/Rayon, Lyocell, and Modal
Alright, so all of these fabrics are similar in the face that they are man-made, but are based on plants giving them some of the nice properties of naturally derived fabrics. What are the differences?
We’ve already noted that viscose and rayon are just different names for the same fabric. Rayon is the North American name and viscose is the European name. These are both quite similar to modal. The only real difference between Viscose and Modal is in how the cellulose fibers are processed after the fabric has been produced. They both use the same chemical process to dissolve plants and create the fiber, but the fibers in modal fabric are put through extra processing to stretch them. This makes modal lighter and finer than viscose rayon and increases the strength of the fibers. This makes modal ideal for athletic clothing or uses in which the fabric is going to be treated a little more harshly. You can also tumble dry modal, which is something you should avoid with viscose rayon. That said, the modal fabric is usually a little too thin and airy to make for good bedding products.
Lyocell is created through a different chemical process than the other three. Whereas Viscose, Rayon, and Modal all use caustic soda to dissolve the plants they start with, the Lyocell process uses an organic compound called M-Methylmorpholine N-oxide (NMMO). Don’t let the name scare you! It’s is a non-toxic and organic compound that is actually more environmentally friendly than the caustic soda used to make Viscose Rayon. The biggest advantage to using NMMO is that it is easier to recapture to create what is known as a closed-loop process, where the chemicals are re-used instead of having to be disposed of. The end result is that Lyocell is somewhat more environmentally friendly because of this.
Despite this difference in product, the actual Viscose Rayon fabric is nearly identical to the Lyocell fabric. They have the same look and feel and moisture-wicking properties that are the hallmarks of these plant-based fabrics.
Summing It All Up
In the end, all of these fabrics are very similar. The biggest difference is that Modal is a bit finer and lighter than the others. It is also produces stronger fibers and is ideal for more intense use in athletic clothing.
The only real difference between Viscose/Rayon and Lyocell is the chemicals used to transform the plants they start with into fiber. As far as how they feel and perform, there is almost difference between these fabrics though. If environmental friendliness is your topic concern, then Lyocell does have some advantages over any of the others.