Polyisobutylene Chemical Properties

Melting point:

54-56 °C

Boiling point:

300 °C

Density 

0.92 g/mL at 25 °C (lit.)

Tg

-61

Tg

-62

Tg

-64

Tg

-75

refractive index 

n20/D 1.51

Flash point:

>212

Flash point:

>482

form 

slab/chunk

Stability:

Stability Combustible. Incompatible with strong oxidizing agents.

InChI

InChI=1S/C4H8/c1-4(2)3/h1H2,2-3H3

InChIKey

VQTUBCCKSQIDNK-UHFFFAOYSA-N

SMILES

C=C(C)C

EPA Substance Registry System

Polyisobutylene (9003-27-4)

Safety Information

Safety Statements 

24/25

WGK Germany 

3

RTECS 

UD1010000

TSCA 

TSCA listed

HS Code 

39022000

Hazardous Substances Data

9003-27-4(Hazardous Substances Data)

MSDS

• Language:English Provider:ACROS
• Language:English Provider:SigmaAldrich

Polyisobutylene Usage And Synthesis

Chemical Properties

Polyisobutylene is composed of long-chain hydrocarbon formed by polymerization of isobutene, and is extremely stable under normal conditions. It is transparent non-noxious high-consistency semi-solid polymer free of impurities.

Chemical Properties

The physical properties of polyisobutene are very dependent on molecular weight. Polymers with average molecular weight (Mw) of about 15 000 are sticky viscous liquids whilst those with molecular weight of 100000-200000 are rubber-like, resembling unmilled crepe rubber.
Polyisobutene is non-crystalline when unstretched and is therefore soluble at room temperature in hydrocarbons and halogenated hydrocarbons. The material is resistant to most acids, alkalis and aqueous solutions, as would be expected from its saturated hydrocarbon structure and absence of tertiary hydrogen atoms. The lack of tertiary hydrogen atoms renders polyisobutene more resistant to oxidation than polypropylene; also, the less numerous and partially shielded methylene groups in polyisobutene are less reactive than those in polyethylene. However, polyisobutene is rather susceptible to thermal degradation since chain scission is favoured by the greater stability of the resultant tertiary free radical:
Polyisobutene may be chlorinated but the reaction is accompanied by severe degradation.
A limitation of polyisobutene is its tendency to cold flow and, as a result, the polymer finds little use in self-supporting form. Applications are restricted mainly to adhesives, fabric and paper coatings, and blends with other polymers. Low molecular weight polyisobutene is also used in caulking compounds.

Uses

polyisobutene (hydrogenated) is an emollient.
Polyisobutylene, sometimes called butyl rubber, and other times PIB, is a vinyl polymer. It's very similar to polyethylene and polypropylene in structure, except that every other carbon is substituted with two methyl groups. It is made from the monomer isobutylene, by cationic vinyl polymerization.
Polyisobutylene is a synthetic rubber, or elastomer. It's special because it's the only rubber that's gas impermeable. That is, it's the only rubber that can hold air for long periods of time. You may have noticed that balloons will go flat after a few days. This is because they are made of polyisoprene, which is not gas impermeable. Because polyisobutylene will hold air, it is used to make things like the inner tubes, liner layers of tires, and the inner liners of basketballs.

Preparation

Silicone rubbers are prepared as follows:

Other groups may replace the methyl groups. Silicone rubbers have excellent ozone and weathering resistance, good electrical properties, and good adhesion to metal.

Definition

ChEBI: A polymer composed of repeating 1,1-dimethylethylene units. 2-methylprop-1-ene (1,1-Dimethylethylene) is an alkene that is prop-1-ene substituted by a methyl group at position 2. It is an alkene and a gas molecular entity.

Application

Polyisobutylene (PIB) is a vinyl polymer with a uniquely low water diffusion rate and low glass transition temperature (Tg) (-75 °C). It is widely available for use in the following ways:
(1) PIB can be used as a common encapsulation material for photovoltaic modules.
(2) Chemically inert elastomers with oxidation and thermal degradation resistance and low gas permeability.
(3) Plasticisers in rubber formulations and sporting goods (e.g. golf clubs, tennis rackets, grips for bicycles and tools).
(4) Adhesive compositions used as wound dressings where PIB acts as a tackifier.
(5) Functionalisation of polyisobutylene with pyrene by photoinduced radical addition of 1-bromomethylpyrene in the presence of Mn2(CO)10 during the preparation of polyisobutylene-based block copolymers.
(6) Highly reactive polyisobutylene (HRPIB) is the most important industrial polymer material used as a lubricant, fuel and polymer additive. In contrast to conventional Polyisobutylene, HRPIB is a polymer using olefins as end groups.

Solubility in organics

non-polar organic solvents (i.e. aliphatic, aromatic, cyclic and halogenated hydrocarbons), THF

Polyisobutylene(9003-27-4)Related Product Information

• Polybutene
• butyl rubber
• Ferric acetylacetonate
• Tosylmethyl isocyanide
• 1,1,3,3-TETRAMETHYLBUTYL ISOCYANIDE
• TRIS(2,2,6,6-TETRAMETHYL-3,5-HEPTANEDIONATO)EUROPIUM(III)
• Aluminum acetylacetonate
• N-BUTYLISOCYANIDE
• Tris(2,4-pentanedionato)chroMiuM(III)
• Ethyl isocyanoacetate
• Benzyl isocyanide
• TRIS(2,2,6,6-TETRAMETHYL-3,5-HEPTANEDIONATO)DYSPROSIUM(III)
• Cupric acetylacetonate
• DICHLORO(ETHYLENEDIAMINE)PLATINUM(II)
• 2,4-PENTANEDIONE, SILVER DERIVATIVE
• COBALT(II) ACETYLACETONATE
• METHYL ISOCYANOACETATE
• PHENYLSELENOL
• Polyisobutene