As you have seen here in our blog, magnesium oxide is an essential compound in the composition of quality products for various industrial applications. In this article, we will specify a very important use for the industry in general, which is the use of the raw material in fluoroelastomer rubber, a material that is extremely resistant to chemical attacks and high temperatures.
In this way, even under adverse conditions, fluorinated rubber – as it is also known – retains its properties. However, this requires that the curing process takes place in a proper way. And this is where magnesium oxide plays a primary role in the process. Let’s check it out?
Magnesium oxide in the curing process of fluoroelastomer rubber
Magnesium oxide is a curing agent in halogenated rubber formulations, such as fluoroelastomer. In this process, cross-linking of the fluoroelastomer rubber takes place, which changes the chemical structure of the rubber forming a network of molecules linked together. This forms a three-dimensional elastic network, with bonds of molecules along the chain. By applying magnesium oxide to the fluoroelastomer compounds, the reactivity rate of the compound is controlled.
In these cases, magnesium oxide has two functions: firstly, it acts as a hydrogen fluoride receptor, but it also acts as a receptor for fluoride by-products during curing and after cross-linking.
Magnesium oxide is used to remove fluorides and hydrogen from the polymer to create unsaturation in the polymer chain – i.e., double bonds – by cross-chain addition. Additionally, it acts as an acid receptor, stabilizing the curing system, either by diamine, bisphenol, or with organic peroxides that will promote a radical by hydrogen or bromine extraction.
The different types of magnesium oxide
It is important to say that there are several magnesium oxides on the market, which can be divided into two groups: mineral or synthetic. The mineral, as the name implies, comes from rocks, such as Magnesite and Brucite. Synthetic, on the other hand, is usually extracted from seawater or even brine in the form of magnesium chloride and synthesized to magnesium hydroxide.
In the halogenated rubber industry, the most commonly used type of magnesium oxide is synthetic magnesium oxide, because its surface area and particle size distribution are ideal for the cross-linking process of fluoroelastomer compounds.
But what are the benefits of magnesium oxide in this application anyway?
The main benefit, without doubt, is the effectiveness of magnesium oxide for curing fluoroelastomer rubber. The surface area activity indicates the ability of magnesium oxide to react with hydrofluoric acid (HF). Therefore, the larger the surface area, the greater the processing safety and crosslinking properties.
These conditions vary, of course, according to the surface areas and how the magnesium oxide calcination process takes place. The fact is, regardless of how the whole process occurs, the result is very positive and results in an optimal healing time.
Now an important question: are you curious about what we did to get to these results? Bel Mag, always concerned about ensuring the best solution for the market, has developed a specific study to justify all these conclusions! Keep following our blog as we will give you details about how this research took place.
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