Rubber has been used for centuries for so many different things. Natural rubber was cured in various ways to make it stronger and to make it easier for people to work with. However, the curing process wasn't perfect, so for many years, people tried to come up with ways to make rubber work better. One very successful process was vulcanization. But, what exactly is vulcanization?
Vulcanization is a process which takes natural rubber and heats it up and adds various chemicals (generally sulfur or sulfur-based) to strengthen and toughen the rubber up. The chemicals and heating process do that by taking the polymer chains which naturally occur in the rubber and making crosslinks in between them. Imagine that the polymer chains in the rubber are like parallel lines. They are just floating around in there, with no real connection to each other. This makes the rubber pretty sticky. Curing the rubber will help to get rid of some of that stickiness, but not enough. When vulcanization is used, the various chemicals and heating processes take those parallel lines and connect them up by creating ties in between them. The parallel lines go from lines that don't touch and aren't necessarily stable to something like a railroad track. The ties in between the polymer chains will make them more stable, which will toughen up the rubber and make it less sticky. Getting rid of that stickiness makes it better for use in products like tires.
Benefits to Vulcanizing Rubber
There are several benefits to vulcanizing natural rubber, aside from the fact that it will get rid of the natural stickiness of the rubber. One of those benefits is that the rubber gains a kind of memory. In this case, memory means that when there is a load on the rubber that deforms the rubber, the rubber will return back to its original shape when the load is removed. Think of a tire when it's put on your car. It's nice and round. When it's on your car, it gets a little deformed because the weight of the car and whatever is in the car weighs it down. But, if the car were to be lifted, the tires would return back to their round shape.
Vulcanization makes natural rubber much more usable in a whole lot of products. Those products span from hockey pucks to insulating gloves that electricians use to handle electrical wires.