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How is butyl rubber different from natural rubber?

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truck tires being removed from their molds — rubber Truck tires being removed from their molds.

Butyl rubber and natural rubber differ significantly in their origins, chemical structures, and performance characteristics.

Origins and Composition
* Natural rubber is a polyterpene hydrocarbon obtained from the latex of tropical trees, primarily Hevea brasiliensis.2
* Butyl rubber is a synthetic copolymer produced by reacting isobutylene with small amounts of isoprene, both of which are derived from petroleum or natural gas.1

Key Differences
* Chemical Resistance: Because butyl rubber contains very few unsaturated groups (carbon-carbon double bonds), it is highly resistant to oxidation and ozone attack, which degrade natural rubber.1
* Permeability: Butyl rubber has an unusually low permeability to gases, making it the preferred material for inner tubes and tubeless tire liners.1
* Performance: Natural rubber is valued for its superior flex resistance and heat buildup properties, making it ideal for heavy-duty tires. In contrast, butyl rubber has poor tread durability, limiting its use in tire treads.21