THE CHEMISTRY OF SHOES AND SCIENCE

 

Shoes are famous savior, supportive sole-mate and in modern terms can be interpreted as a synonym of style. They are an important part of dressing and lifestyle. Can we imagine a world without shoes, now? Impossible, right? But how many times you thank or imagine the science and engineering that led to the development of your style champion and caretaker of your feet?

Yes, these shoes involve equally important and basic engineering as involved in any scientific machinery. Shocked? We will be discussing the chemical aspects and science of footwear and its impact on you and us.

According to “How Shoes Are Made” by The Sneaker Factory, the most crucial feature in shoe design is not the pattern used for the shape and look of the shoe but it’s something else on which the repute, strength, style, comfort, and importance of the product depend. The materials most commonly used in shoe production are leather, textiles, adhesives, synthetics, foam, and most important in modern times is Rubber. Guess what? The study, research, investigation, and production of these fundamental items have their backbone in the fields of science known as Chemistry. The prime focus of the article will be on Rubber sole in footwear. 

Rubber is, say, the blood of trees in some sense.

Let’s start it with clarifying that rubber is not derived from materials similar to plastic, rubber is actually a very natural product. Rubber is derived from ‘hevea brasiliensis’, also known as rubber trees. In a process similar to tapping maple sap of syrup, trees are cut into and the milky white runoff is collected in buckets. This raw material is a type of latex, the materials that make doctor's gloves, and… other more invasive products. Then the latex undergoes heat treatment to break up most of the natural proteins to turn it into rubber. But, do you have this natural rubber in the sole of your shoes or Sneakers? No, it is not that simple.

Most of the famous gum-soles are actually made from polybutadiene, which is a product that comes out of processing oil.

What is Polybutadiene?

Polybutadiene is one of the synthetics that most closely comes to the natural Isoprene rubber, but it is a very, very different material, and being a derivative of plastic, it’s certainly not natural in the same way rubber is. Polybutadiene rubber is a polymer formed from the polymerization of the monomer 1,3-butadiene. Polybutadiene has a high resistance to wear and is used especially in the manufacture of tires, and widely for making shoes and sandals. You have exactly the same compound at your feet which is there in a motor, yes. Isn’t it interesting?  Let’s have a look at how polybutadiene looks in chemistry.

Oh! I know it is horrible. Let’s move on to the next surprise

Sneak to sneakers

What if I say sneakers are sneakers due to the thing we are talking here? Yes, it is Rubber. The first rubber-soled shoes didn’t appear until the late 1890s, but the first real sneaker popped up in 1917. The term ‘sneakers’ was derived from the idea that these shoes didn’t make too much noise. The term was first used in the late 1800s when this type of shoe was introduced. Since it has a rubber sole, it doesn’t create a sound (or at least minimal) so one can sneak around wearing shoes with such sole. All thanks to processed rubber. Although it’s also true that some people love the tapping noise of leather sole. Which one are you?

Why Rubber soles are better?

A leather-soled shoe is more comfortable when worn in the summer. There is no doubt that leather soles and leather footwear allow your feet to breathe. But then a pair of rubber soles shoes are multi-weather shoes, that is, the rubber sole footwear is suitable for all seasons. For all intents and purposes, rubber is indestructible. When you are walking on wet pavement or on snow-covered streets, you should definitely wear shoes with rubber soles as they provide better traction on wet surfaces. The chance of slipping also gets reduced. Moreover, rubber sole shoes are an economical and practical choice for footwear.

Not all rubber soles are the same. Depending on the brand and type of shoes and that you are wearing, the various chemically variant rubber soles that are used are as follows:

Resin Rubber:  This type of sole is waterproof and also hard-wearing. However, it tends to feel a bit hard when you are walking on a hard surface. Mind that this resin is nowhere even close to anything edible.

Crepe Rubber: Crepe rubber is considered as the most versatile type of sole for footwear as it is light, flexible, and hard-wearing.

Gristle Rubber: This rubber sole is mostly used in industrial footwear. It is robust in quality.

PVC: Are we wearing pipes? Oh really? Well yes in an analytical sense we are. Soles made of PVC is flexible (like the pipes, funny?) and cheap but can be slippery. At times, cracks also occur.

Polyurethane: If your shoes keep you stuck to even slippery surfaces you should thank this substance as it may be the reason for it. This offers good resistance to slipping. It is light and hard-wearing.

Well we will be discussing these specific types of rubber and their importance for the shoe industry and shoe lovers. Point to be noted is where there is rubber, adhesives should not be ignored.

Let me wind this informative ride up here with an interesting and historical fact-

The shoes which were worn by Neil Armstrong, when he walked on the moon, are probably floating somewhere in space. Surprised? Well, it is true. When he did his famous moonwalk, he was afraid that the shoes he was wearing would be contaminated by foreign, and possibly dangerous space materials. He discarded his shoes outside, in space. They were never found again.

What do you think should we start a mission named searching shoes?

What say?

See you.