If you’re a sneaker enthusiast, you’ve probably experienced the frustration of opening the box of those amazing sneakers you’ve kept for years, only to discover that they’re crumbling, the sole is disintegrating, or the material is simply falling apart. It sounds like magic, but it’s not. The culprit has a name: hydrolysis. And yes, it’s as scary as it sounds. But don’t worry, we’ll explain everything clearly and in a light-hearted way, so you can understand why this happens, which materials are most prone to this problem, and most importantly, how to prevent your precious sneakers from turning to dust.
What is Hydrolysis? The Science Behind “Sneakers That Turn to Dust”
Hydrolysis is a chemical process that occurs when water molecules interact with certain materials, causing their molecular bonds to break. In the case of sneakers, this happens mainly with polyurethane (PU), a very common material in shoe soles and components. When polyurethane comes into contact with moisture in the air or humid environments, the water molecules “attack” the chemical bonds of the material, weakening its structure and eventually causing it to disintegrate.
Imagine polyurethane as a sand castle. Hydrolysis is the ocean wave that gradually knocks down the towers and walls until the castle collapses. In the case of sneakers, the result is that crumbly appearance, soles that crack or even completely detach from the upper (the top part of the sneaker).
Why Does This Happen? The Lifespan of Materials
Everything in life has an expiration date, and the materials used in sneakers are no exception. Polyurethane, although durable and flexible, is not designed to last forever. Over time, especially if the sneakers are stored in inappropriate conditions (such as humid places or with extreme temperature variations), the hydrolysis process is accelerated.
And here’s a fun fact: hydrolysis doesn’t just happen because the sneakers are old. It can even occur in sneakers that have never been worn but have been stored for long periods. That’s why those Air Max or Jordans that you’ve kept in the box for a decade can be in terrible condition, even if they’ve never been on the pavement.
Which Materials Are Most Prone to Hydrolysis?
Not all materials used in sneakers suffer from hydrolysis. Here is a list of the main villains and heroes:
Materials Prone to Hydrolysis:
- Polyurethane (PU): The main culprit. Found in many sneaker soles, especially in models from the 90s and 2000s.
- EVA (Ethylene Vinyl Acetate): Less prone than PU, but can still undergo hydrolysis under extreme conditions.
- Glues and Adhesives: Many glues used in the manufacture of sneakers can also degrade over time, causing parts of the shoe to come loose.
Hydrolysis Resistant Materials:
- Rubber: Materials such as vulcanized rubber are much more durable and resistant to hydrolysis (rubber found in the sole of Vans Old Skool sneakers, for example)
- Leather: As long as it is well cared for, leather tends to last much longer without degrading.
- Modern Synthetic Fabrics: Materials like Kknit (Flyknit: used by Nike, PrimeKnit used by Adidas and EvoKnit used by Puma) are less prone to this problem.
Which Sneaker Models Are Most Affected?
Some iconic models are particularly known for suffering from hydrolysis, especially those that use polyurethane in their soles. Here are some of the “famous” ones that can turn to dust if not properly cared for:
- Nike Air Max 1, 95, 97 and other models in the Air Max line: Air Max technology often uses polyurethane in the midsole, which makes it vulnerable to hydrolysis.
- Air Jordans (especially 90s models): Many classic Jordans, such as the Air Jordan 3, 4, 5, and 6, use PU in their soles.
- Adidas Boost (in rare cases): Although Boost is more resilient, it is not immune to hydrolysis, especially in extreme conditions.
- Vintage Basketball Shoes: Many basketball shoes from the 80s and 90s used polyurethane, making them candidates for disintegration.
How to Avoid Hydrolysis and Save Your Sneakers?
Now that you know what causes hydrolysis, let’s get to the point: how to prevent your sneakers from turning to dust. Here are some practical tips:
1. Store in a Cool, Dry Place
Moisture is the number one enemy of sneakers. Store your sneakers in a dry place, away from bathrooms, basements, or areas where moisture can accumulate. A closet in your bedroom or in an air-conditioned area is ideal.
2. Use Silica Gel
Those little silica gel packets that come in sneaker boxes aren’t just for show. They help absorb moisture and keep the inside of the box dry. Place a few packets inside your sneakers and in the box where you store them.
Want to keep your favorite sneakers from turning to dust before their time? Silica gel can be your best friend! This magical powder (actually, it’s porous silicon dioxide granules) works as a super moisture absorber. Through a process called adsorption , it captures water molecules in the air and prevents moisture from attacking the sole of your sneakers, slowing down that dreaded hydrolysis process . So, whenever you put your sneakers away, throw a few silica gel sachets in the box or closet 🔥👟
3. Avoid Temperature Extremes
Very hot or very cold places can accelerate the degradation of the materials. Avoid storing your sneakers near heaters, radiators or in areas that receive direct sunlight for long periods.
4. Use them once in a while
It may seem strange, but wearing your sneakers occasionally can help extend their lifespan. The movement and flexing of the sole can prevent the material from hardening and breaking down.
5. Invest in Professional Conservation
If you have a pair of rare or very valuable sneakers, consider taking them to a shoe care specialist. They can apply products that slow down hydrolysis and help keep your sneakers in good condition.
6. Avoid Excessive Washing
Washing sneakers frequently, especially in washing machines, can accelerate the degradation of the materials. Prefer to clean them by hand and use products specifically designed for shoes.
What If My Sneakers Are Already Crumbling? Is There a Solution?
Unfortunately, once hydrolysis begins, there’s not much you can do to reverse the process. However, depending on the condition of your shoe, you can try a few solutions:
- Recoloring and Repair: If only parts of the shoe are affected, a sneaker restoration specialist can help rebuild or replace damaged parts.
- Sole Swap: In some cases, it is possible to replace the sole with a new one, especially if the upper (top part) is still in good condition. Or create a Hybrid Sneaker that would be the upper of a sneaker with another sole.
- Turn it into Art: If your sneakers are completely lost, why not turn them into a decorative piece? Many collectors use old sneakers as display items.
Conclusion: Take Good Care of Your Sneakers
Hydrolysis is a natural phenomenon, but that doesn’t mean you have to say goodbye to your favorite sneakers too soon. With the right care, you can extend the life of your sneakers and keep them in great condition for many years. Remember: proper storage, moderate use, and a little attention can make all the difference.
So next time you open the box of those Air Maxes or Jordans you’ve been saving so much, hopefully they’ll be intact and ready to wear. And if they’re not, at least now you know why that happened and how to prevent it from happening again in the future. After all, sneakers are more than just shoes – they’re stories, memories, and often true works of art. And they deserve the best care in the world.
FAQ: Questions and Answers about Hydrolysis in Tennis Shoes
Why are my sneakers crumbling even though I haven’t used them?
Ah, the classic tragedy of the sneaker that turns to dust without ever having been on the street! This happens because of hydrolysis, a chemical process that breaks down the molecules of the material (especially polyurethane) when it comes into contact with moisture in the air. Even when stored in its box, the sneaker is not immune to time and environmental conditions. It’s as if it were aging in slow motion, until one day… poof!
What is hydrolysis and why does it affect tennis?
Hydrolysis is a chemical reaction in which water molecules “attack” the bonds of materials such as polyurethane, causing them to degrade. In sneakers, this mainly occurs on the soles and glued parts. It’s as if the sneaker is fighting a losing battle against humidity, and unfortunately, water always wins.
Which materials are most prone to hydrolysis?
The main culprit is polyurethane (PU) , which is often used in the soles of old sneakers. EVA can also undergo hydrolysis, but it is more resistant. Materials such as vulcanized rubber and leather are more durable and less prone to this problem. So, if you want sneakers that will last a lifetime, keep an eye on the materials!
Which sneaker models are most affected by hydrolysis?
Some classic cars are notorious for suffering from hydrolysis, especially those that use polyurethane. The main ones “affected” are:
- Nike Air Max 1, 95 and 97
- Air Jordans from the 90s (like the Jordan 3, 4, 5, and 6)
- Old Basketball Shoes
If you have any of these, you might want to keep an eye out for them!
How can I prevent my sneakers from suffering hydrolysis?
Here are some tips to save your sneakers:
- Store them in a cool, dry place .
- Use silica gel inside the box to absorb moisture.
- Avoid extremes of temperature (do not leave it near a heater or in the sun).
- Wear your sneakers from time to time to prevent the materials from hardening.
By taking these precautions, your sneakers will have a better chance of surviving the test of time!
Can I fix a sneaker that is already falling apart?
It depends on the level of damage! If only certain parts are damaged, a sneaker restoration specialist can help replace or rebuild damaged parts. In more severe cases, it may be necessary to replace the sole. However, if the sneaker has already turned to dust, unfortunately, there is not much that can be done. How about turning it into a decorative piece?
Can new sneakers also suffer from hydrolysis?
Yes, but it’s rarer. Hydrolysis usually occurs in older sneakers or those that have been stored for long periods of time in inappropriate conditions. However, if you store new sneakers in a humid place for years, they can also suffer from the problem. So, don’t forget to store your sneakers in the basement, okay?
Is there any product to prevent hydrolysis?
There is no miracle product that completely prevents hydrolysis, but you can slow down the process with some precautions:
- Use silica gel to control moisture.
- Apply specific tennis care products .
- Keep your sneakers in a climate-controlled environment and away from moisture.
And of course, wear your sneakers every now and then to keep them “alive”!
