Other important polymers

Butyl rubber

Butyl rubber is a synthetic rubber, a copolymer of isobutylene with isoprene. The abbreviation IIR stands for Isobutylene Isoprene Rubber.

Polyisobutylene, also known as "PIB" or polyisobutene, (C₄H₈)_n, is the homopolymer 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 polypropylene, having two methyl groups substituted on every other carbon atom.

Properties:

Poly isobutylene is a colorless to light yellow visco–elastic material. It is generally odorless and tasteless, though it may exhibit a slight characteristic odor.

Butyl rubber has excellent impermeability, and the long poly isobutylene segments of its polymer chains give it good flex properties.

The formula for PIB is: − (− CH₂ − C(CH₃)₂ −)_n−

The formula for IIR is:

A synthetic rubber, or elastomer, butyl rubber is impermeable to air and used in many applications requiring an airtight rubber.

Uses: Polyisobutylene and and butyl rubber are used in the manufacture of adhesives, agricultural chemicals, fiber optic compounds, ball bladders,caulks and sealants, cling film, electrical fluids, lubricants (2 cycle engine oil), paper and pulp, personal care products, pigment concentrates, for rubber and polymer modification, for protecting and sealing certain equipment for use in areas where chemical weapons are present, as a gasoline/diesel fuel additive, and even in chewing gum.

The first major application of butyl rubber was tire inner tubes. This remains an important segment of its market even today.

Polymonochloro trifluoroethylene

It is obtained from monochlorotrifluoroethylene.

Properties:

Due to the presence of chlorin, it is less resistant to heat and chemicals.

Uses:

It is used as a coating on cooking utencils.

Polymethylmetha acrylate(PMMA)

It is obtained by polymerization of methyl methacrylate (MMA) in the presence of organic peroxide. The starting material MMA is obtained from acetone in the following way.

Properties:

PMMA is also known as plexiglass or Lucite. It has lightweight and can be moulded almost to any desired shape, the scratching on this can be removed easily by rubbing with solvent such as acetone. So it is the best alternative to glass. Also, optical clarity is the main feature of this polymer.

Uses:

It is used for making optical lenses, aircraft windows, plastic jewellery, etc.

Polyethyl acrylate (PEA)

It is a polymer of ethyl acrylate

It is a tough and some what rubber like product. It is used in the manufacture of cloth, blankets and carpets etc.

Glyptal

The monomers of glyptal are ethane – 1,2 – diol and 1,2 – benzene dicarboxylic acid (pthalic acid)

Uses:

It is used in the manufacture of paints & lacqers.

Formaldehyde Resins

These are typical thermosetting condensation polymers. On heating these resins become highly cross linked.These are of following types:

Urea–Formaldehyde bakelites

These are the Bakelite type polymers from urea & formaldehyde

Uses:

These are used for making buttons adhesives, electrical goods, etc.

Phenol – Formaldehyde bakelite

Phenol and formaldehyde condense in presence of caustic soda (catalyst) to give a linear polymer containing alternate phenol and methylene units.

Uses:

Photograph records, electrical goods, formicable tops, gear wheels for steel rolling and paper mills, protective casting, etc are some of the products made from Phenol–formaldehyde resins.

Melamine–Formaldehyde resin

When melamine copolymerises with formaldehyde melamine formaldehyde resins are formed.

Uses:

These are used for making decorative articles and unbreakable dinner – wares.