Silicone gum is an unvulcanized (uncrosslinked) basic polysiloxane with a high molecular weight, primarily used to manufacture HTV (High Temperature Vulcanization) silicone rubber, pigment masterbatches, and siloxane masterbatches.
In more detail:
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Polysiloxane Structure: Silicone gum consists of long, linear chains of repeating siloxane units (silicon-oxygen bonds) with organic groups attached to the silicon atoms.
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High Molecular Weight: The "gum" characteristic comes from the long polymer chains, giving it a high molecular weight and viscous nature. This high molecular weight is crucial for its eventual properties as a rubber.
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Unvulcanized (Uncrosslinked): In its gum form, the polysiloxane chains are not chemically linked together (crosslinked). This absence of crosslinking makes it easily deformable and processable. The vulcanization or curing process, which involves crosslinking, transforms the gum into a strong, elastic silicone rubber.
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Applications:
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HTV Silicone Rubber Production: Silicone gum is a key raw material for manufacturing HTV silicone rubber, which requires a curing process (often with heat) to create the final rubber product.
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Pigment Masterbatches: It acts as a carrier for pigments, allowing for uniform dispersion and easy incorporation into other materials.
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Siloxane Masterbatches: Similar to pigment masterbatches, it serves as a carrier for siloxane additives, improving their dispersion and processability.
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SiSiB Silicone Gum: The provided reference specifically mentions SiSiB silicone gum, implying it is a commercially available product designed for the aforementioned applications. Other manufacturers also produce silicone gums with varying properties.
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Key Properties Contributing to its Usefulness:
- Processability: The gum's unvulcanized state allows for easy shaping, molding, and mixing with other components.
- Versatility: It can be formulated to achieve a wide range of properties in the final rubber product, depending on the crosslinking method and additives used.
- Durability: Once vulcanized, silicone rubber exhibits excellent resistance to heat, chemicals, weathering, and aging.
In summary, silicone gum is the raw, unvulcanized form of silicone rubber, essential for producing various silicone-based products with tailored properties through subsequent crosslinking.
