Vulcanization of Silicone Gum

Vulcanization of Silicone Gum

Vulcanization is a process that gives silicone rubber its special properties, including its strength and durability.silicone gum material vulcanizing agent It is usually done by exposing the elastomer to heat and chemicals, which creates cross-linking between the molecules that makes it harder and less flexible than non-vulcanized silicone rubber. It also improves its resistance to extreme temperatures and makes it more compatible with some adhesives and sealants. Vulcanized silicone rubber is often used in medical devices, automotive products, and electronics. It is also found in everyday household items like nipples and hairspray.

The basic raw materials that are mixed to make vulcanized silicone include silicone polymers, fillers, and additives.silicone gum material vulcanizing agent The polymers are kneaded under heat and pressure to mix them well. This is called a base compound, and it can be formed into different shapes using extrusion (for tubes and hoses) or by rolling out into sheets, or it can be molded into more complex pieces using compression or injection molding.

After the base compound is shaped into the desired shape, it undergoes a process known as vulcanization.silicone gum material vulcanizing agent This uses a curing agent to generate heat to cause the polymer chains to cross-link with each other. It can be done at high temperatures (known as High-Temperature Vulcanization or HTV) or at room temperature. When done at room temperature, it is called Room Temperature Vulcanization or RTV.

During the vulcanization process, sulfur atoms are incorporated into the polymer chain to form cross-links between the molecules. This causes the molecules to bond together to form a three-dimensional network that forms the thermoset of a cured silicone rubber or elastomer. The cross-links also make it much stronger and more durable than uncrosslinked silicone. This is why vulcanized silicone is more expensive than non-vulcanized silicone.

The chemistry of vulcanization is extremely complicated, but one of the key ingredients that makes it work is a molecule called silane. A silane is a chemical compound that contains a silicon group and an oxygen atom. When it comes into contact with the elastomer, it can react with the siloxane chains in the elastomer to form the cross-links. This is why it is important to use a high-quality, stable silane that has been carefully selected for its compatibility with elastomers and the ability to create strong, durable cross-links.

A specialized silane called 2,5-Dimethyl has a high decomposition temperature and good scorch performance. It can be used to cross-link a wide range of silicone rubbers, and it is suitable for use in RTV and HTV vulcanizates. It is also suitable for blending with nitrile rubber (NR) and ethylene-vinyl acetate (EVA) copolymers, improving their flame retardancy.

Liquid silicone rubbers can also be cured using silanes, but they cure more slowly than HTV silicones and liberate volatile by-products during the curing process. This type of vulcanization is not as good for a number of applications as the HTV method, but it may be an appropriate option for some situations. The future of vulcanized silicone is uncertain, but there are many options being explored to make the process more sustainable.

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