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Silicone Engineering > Blog > Difference between ‘curing’ and ‘vulcanisation’? – Silicone

Difference between ‘curing’ and ‘vulcanisation’? – Silicone

In practical terms, there is no difference between curing and vulcanisation. The name for the process by which any elastomer material becomes cross linked is curing. Vulcanisation is the name used for curing when a system uses sulphur.

What does HTV mean?

High Temperature Vulcanisation

Why are some silicone rubbers specified as ‘addition cure’?

Addition cure silicone is what we call Platinum cured. Addition Cure refers to the method by which the cross links form in the rubber. In a traditional peroxide cure silicone rubber, thermal breakdown of the peroxide creates the chemical that forms the cross links between the polymer chain. In an addition cure system certain side branches on the chains themselves link together to form the cross links. In many common compounds this reaction needs platinum to be present in the formulation to act as a catalyst.

What does thermoset (cross linked) mean?

Silicone rubber used at Silicone Engineering is mainly of the HCR variety. In this world of abbreviations people sometimes understandably get mixed up. HCR is often referred to as Heat Cured Rubber however, High Consistency Rubber is the correct abbreviation.

HCR uses a heat-activated peroxide cure catalyst system to chemically cure the rubber. This converts the material from compound to rubber form.

A cross link is a chemical bond that links one polymer chain to another. Thermoset simply means the silicone compound has been “Set” by means of “Temperature” (Thermo).

The most basic answer is that a Thermoset is a material that has been irreversibly cured, normally by the use of temperature. Cross Links are the chemical bonds that form between the individual polymer strands during the curing process. When something has been “Cross Linked” this means that it has been cured.

About the author

Simon Holmes
 

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