Butyl rubber

<p>Butyl rubber, sometimes just called butyl, is a <a href="/facts/Synthetic_rubber/58Fq4XYx">synthetic rubber</a>, a <a href="/facts/Copolymer/35D97DuV">copolymer</a> of <a href="/facts/Isobutylene/Bl5REcDx">isobutylene</a> with <a href="/facts/Isoprene/8ArKUyzT">isoprene</a>. The abbreviation IIR stands for isobutylene isoprene rubber. Polyisobutylene, also known as "PIB" or polyisobutene, (C4H8)n, is the <a href="/facts/Homopolymer/eF32E50K">homopolymer</a> of isobutylene, or 2-methyl-1-propene, on which butyl rubber is based. Butyl rubber is produced by polymerization of about 98% of isobutylene with about 2% of isoprene. Structurally, polyisobutylene resembles <a href="/facts/Polypropylene/HM9PvoCz">polypropylene</a>, but has two <a href="/facts/Methyl_group/fkM97EMD">methyl groups</a> substituted on every other <a href="/facts/Carbon/ukrgQexo">carbon</a> atom, rather than one. Polyisobutylene is a colorless to light yellow <a href="/facts/Viscoelastic/pDhHgx2T">viscoelastic</a> material. It is generally odorless and tasteless, though it may exhibit a slight characteristic odor.
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Butyl rubber open-in-new

Butyl rubber