The vulcanization is a process by which heat is obtained rubber oil in the presence of the sulfur in order to make it a more material hard and the same time more resistant .
What is vulcanization?
The vulcanization is a process through which is achieved to a remarkable improvement to features that have the natural rubbers and synthetic , and reducing the minimum their plastic properties increasing at the same time its elastic properties .
- What is vulcanization
- Vulcanization process
- Tools and machinery
- Vulcanization applications
What is vulcanization
Vulcanization consists of a chemical reaction by means of which the filiform molecules that the rubber possesses intertwine with each other, which generally happens due to the action of sulfur but that can also happen by the addition of peroxides , thus forming way a three-dimensional grid . It is a process that manages to considerably improve the characteristics of rubbers because by its process it reduces the plastic properties that rubbers have and at the same time manages to increase their elastic conditions .
It is a process that consists of heating the rubber when it is raw in the presence of sulfur , in order to convert it into a harder material that is also resistant to cold. In the process, the linear polymers that are close together form cross-linking bridges between them, obtaining as a final result that the rubber molecules remain attached to each other, making the rubber more durable , resistant and does not lose its natural elasticity .
Originally there is data that in the Olmec culture , they made rubber balls that were used to play ball using plant extracts. According to the data that have been obtained from some investigations, the discovery of the vulcanization process arose thanks to Charles Goodyear , who in a totally accidental way in 1839, placed a container with sulfur and rubber above a heat source . The result of this was that the mixture that had been formed hardened and became completely waterproof , and was then given in the name of vulcanization, apparently in honor of the Vulcan God .
The process of vulcanization runs under pressure in molds suitable for this purpose and at a temperature at generally 150 ° C. Depending on the temperature having vulcanization and size having the article, the duration of the vulcanization process can reach vary between a few minutes and hours. During the vulcanization process, the closest parallel linear polymers form cross-linking bridges between themselves. As a result we obtain that the elastic molecules of the rubber bond with each other. This vulcanization process then has the ability to give rise to a more rubberdurable , which is able to resist chemical attacks without losing its natural elasticity . It is also a process by which the sticky surface of the material is transformed into a smooth surface that can adhere to metal or plastic substrates.
It is important to mention that vulcanization is a curing process that cannot be reversed and that defines cured rubbers as thermoset materials , in other words, in materials that do not melt with heat and takes them out of the category of thermoplastics , as in the case of polyethylene and polypropylene.
Tools and machinery
Different types of machines are used in the vulcanization process that are in charge of laminating and extruding . Sometimes it heated in molds with pressure , and other molds are used which are heated by steam and further have a close airtight . The risks that can occur with machinery are accidents of entrapment, crushing, etc., which must be prevented by means of specific devices. On some occasions vulcanizing ovens and autoclaves can be used , which must have safety valves ,pressure gauges and interlocks and doors.
It is important to mention that in order to accelerate the vulcanization process and in order to improve the properties of the products that have been vulcanized, accelerator products , such as products derived from dithiocarbomine acid and mercaptobenzothiazole , are also added to the rubber. , diphenylguanidine which can be added alone or in combination.
There are many vulcanization methods, including compression molding, which is the most widely used. Rubber curing processes are common such as sulfur systems , peroxides , metal oxides , acetoxysilane , amine crosslinking , and dysfunctional compounds .
There are many possible applications in which the vulcanization process can be used, among them we can mention the manufacture of rubber articles , such as automobile tires , sleeves , gaskets , footwear , gloves , etc. It is also used in the creation of foam rubber and soft rubber .
Its main importance is that through the process, it is possible to obtain a material that is more resistant and has greater flexibility , increasing its proportion to 20% and also, it is possible to prolong the cooking action by means of which it is possible to obtain rubber hardened .