Why viscose is weaker when it is wet

Short answer: Water gets into the fiber and pushes the cellulose molecules apart. That makes the fiber softer and weaker until it dries again and regains its original strength.

Water weakens the bonds

Cellulose is held together by bonds between molecules, which water partly breaks as it enters the fiber. That is why a wet viscose fiber is weaker than a dry one, even though it is the same fiber either way. See facts about bamboo for background on the fiber's structure.

That is why you should not wring it

Wringing wet viscose stretches the fibers permanently, because they are far more prone to damage in their weakened state. Instead press the water out in a towel by rolling the fabric up. See washing and care for the steps that protect the fabric the most.

That is why heavy pieces should lie flat

A heavy, wet piece that hangs stretches under its own weight while the fiber is weakened by the water. So lay it flat to dry on a towel or a drying rack instead of hanging it on a hanger.

Strength comes back

As the fabric dries, it regains its original strength, because the bonds in the cellulose reform as the water disappears. Damage only happens if the fabric was stretched or wrung out while it was still wet and vulnerable.

Modal is stronger when wet

Modal is stretched during the manufacturing process itself and therefore loses less strength in a wet state than ordinary viscose. See advantages of bamboo viscose for a comparison of how different cellulose fibers perform under different conditions in daily life.

What happens during a machine wash

A gentle cycle at low temperature stresses the fibers less than a normal or heavy cycle, because mechanical movement in the water can stretch the weakened fibers. Use a program with low spin for viscose and bamboo clothing.

Drying without spinning

If the fabric is still very wet after the machine, it is better to let it drip dry than to spin it further, because spinning stretches the fibers in much the same way that wringing by hand does.

Signs of overstretched fabric

A fabric that was stretched too much while wet sits looser and feels thinner afterward, even once it is dry again. See bamboo underwear for women for items made for gentle handling through the whole process.

In short

Viscose is weaker when wet because water partly breaks the bonds in the fiber. Never wring wet fabric, lay heavy pieces flat, and use a low spin cycle. That way the fabric regains its full strength once it dries again.

Frequently asked questions

Is viscose weaker when wet?

Yes. Water partly breaks the bonds in the fiber until the fabric dries again and the cellulose molecules return to their original, stronger structure.

Can you wring out wet viscose?

No. Wringing stretches the fibers permanently, because they are weaker in a wet state. Press the water out in a towel instead, without twisting the fabric.