In our previous articles, we have already reviewed how the rubber, as well as what makes molecular biology so unique. spatial structure, which is responsible for its unrivalled flexibility and popularity. However, rubber is not yet rubber; in order to manufacture rubber by enhancing its beneficial properties, the rubber must be vulcanised. However, it does matter what type of rubber is used to make the rubber.
Not all rubber is the same
Since the rubber used has a fundamental impact on the manufactured rubber quality, and its properties, it is worth reviewing the classification of rubbers used in rubber manufacturing.
The most basic division is described in the previous part of our series of articles. natural rubber and synthetic rubber distinction between.
The latter were created due to a shortage of raw materials following the boom in rubber production. These materials in chemical plants, mainly from crude oil and natural gas.
In certain cases and areas of application synthetic rubbers have more favourable properties than natural rubber, As a result, synthetic rubber, which is generally more expensive than natural rubber, now accounts for around 50 per cent of the raw material used in rubber production.
In our previous article, we already mentioned rubber – especially pull following – its deformation and the rearrangement of the rubber macromolecules after the force has ceased to act.
In the case of cyclic loading, the deformation curves (histograms) of the first few loading cycles will be similar in shape but different in value. This phenomenon Mullins phenomenon or Mullins effect let's call it.
The most characteristic properties of different types of rubber
Natural rubber
In the spatial structure of natural rubber, repeating molecular segments follow each other regularly in the same position, resulting in a relatively high degree of orderliness.
Natural rubber always contains protein-based substances, which have strong interactions between their polar molecular groups, exhibit a higher than average degree of crystallisation. As a result, natural rubber also crystallises quite well, especially when subjected to tension. The Rubber made from natural rubber has very good dynamic properties., low hysteresis.
However, protein content is not an advantage in all areas: natural rubber-based tyres are not very water-resistant and are not resistant to oils either.
Tyres made from natural rubber have good wear resistance.
Isoprene rubber
Its main chemical component is identical to that of natural rubber, but it does not have such a regular structure, and does not contain protein. Because of this, it crystallises less, its dynamic properties are slightly inferior to those of natural rubber. It has low abrasion resistance and poor oil resistance, similar to natural rubber, but better water resistance.
Butadiene rubber
In the structure of butadiene rubber, the interaction between neighbouring macromolecules is weak. This means that rubber made from this raw material highly flexible, with outstanding dynamic properties and wear resistance will be a product with.
Butadiene-styrene rubber
A copolymer of butadiene and styrene (or methyl styrene), whose properties are essentially determined by the ratio of butadiene to styrene.
Thanks to styrene high tensile strength and better heat resistance as traditional rubber. As it is relatively inexpensive, it is often used in the tread compound of tyres.
Butyl rubber
Polyisobutylene has a very compact structure, which is why, compared to other types of rubber, it known for its very low air permeability and good chemical resistance.
Chloroprene rubber
Its main component is polychloroprene. One of its common commercial variants is used as a base material for diving suits. Neoprene.
Ethylene propylene rubber
Ethylene-propylene rubbers they can withstand temperatures much higher than most, which is why they are used as a raw material for the manufacture of heat-resistant tyres.
The next and final part of our series of articles will discuss how rubber can be produced from the above types of rubber during vulcanisation.
Image illustrating the Mullins phenomenon Eszter Fehér comes from his study.
