Untitled Document

If you have come to this page from a search engine please click here for a full site map and access to all site pages

The classification system used in the rubber industry for naming elastomers is based on that described in ISO 1629-1976. The last letter of the identification code defines the basic group to which the polymer belongs whilst the earlier ones provide more specific information and in many cases define the polymer absolutely. The list below is not exhaustive but covers many of the more common elastomers or rubbers and some “rubber-like” materials.

'M' Group: Rubbers with a Saturated -C-C- Main Chain:

IM	Polyisobutylene (e.g. VISTANEX), a soft inert polymer.
EPM	Copolymer of ethylene and propylene, rubber-like material.
EPDM	A terpolymer of ethylene, propylene and a di- or polyene giving pendent olefin groups as crosslinking sites (e.g. NORDEL).
CSM	Chlorosulphonated polyethylene (e.g. HYPALON), containing both C-Cl and C-SO2CI groups. Cl content 20-45%; S content 0.5-2.5%. Optimum properties 30% Cl, 1.5% S; ozone-resistant rubber also used in varnishes.
FPM	Fluoro/fluoroalkyl groups on C-C backbone (e.g. VITON, FLUOREL - copolymers of hexafluoropropylene and vinylidene fluoride). (e.g. TECHNOFLON copolymer of vinylidene fluoride and 1-hydropentafluoropropylene.
CFM	As FPM, but containing Cl as well as F; vinylidene fluoride (VF): chlorotrifluoroethylene (CTFE) copolymer (e.g. VOLTALEF, KEL F).

‘O’ Group: Rubbers with Carbon and Oxygen in the Main Chain:

These materials have good heat resistance and good low temperature properties.

CO	Poly(epichlorohydrin) (HERCLOR H) - the parent material from which comes:
ECO	Copolymer of epichlorohydrin and ethylene oxide (HERCLOR C).
GPO	Copolymer of propylene oxide and allyl glycidyl ether (PAREL).

‘Q’ Group: Silicone Rubbers:

These are all relatively stable thermally and because of their cold cure characteristics may be used as electrical insulants, seals, moulds, etc.

MQ	Polydimethylsiloxane; depending on the molar mass this can be an oil, wax or rubber.
MPQ	as MQ with the addition of phenylmethylsiloxane.
MPVQ	as above but with vinyl groups.
MFQ	as MQ but fluorinated.

'R' Group: Rubbers with an Unsaturated Carbon Backbone:

ABR	Refers to copolymers of butadiene and methyl methacrylate (e.g. BUTAKON ML) used to impregnate paper but also includes the terpolymer with acrylonitrile (primer, before adhesive layer applied) and tetrapolymer with styrene (used as a synthetic rubber).
BR	Poly(butadiene) - available as high cis (98%+), high trans (98% +) and anywhere in between. Can also have vinyl groups present at any level. General-purpose rubbers usually 90%+ cis or about 45% cis 45% trans 10% vinyl. High vinyls have some specialist uses.
CR	Poly(ß-chlorobutadiene) (e.g. CHLOROPRENE, NEOPRENE). Two main types, 'G', amber in colour with large molar mass range centred at about 100 000; 'W’, white, molar mass of narrower range and centred about 200 000. Used as an adhesive or where oil or ozone resistance required; gaskets, subaqua suits, etc.
IIR	Copolymer of isobutylene and diene such as butadiene or isoprene (BUTYL). Only a small amount of diene added (ca 2% - 5%) to give crosslinkable sites. Has low gas permeability, hence uses in inflatable products, and as general-purpose rubber.
CIIR	Chlorinated IIR} with 2-3% w/w halogen to decrease gas.
BIIR	Brominated IIR} permeability and improve self-adhesion on building.
IR	Synthetic cis-poly(isoprene) (e.g. CARIFLEX, NATSYN, SKI3) cis level 90-99%, remainder trans and vinyl. General-purpose rubber.
NBR	Copolymer; acrylonitrile and butadiene (e.g. KRYNAC, NITRILE) available with a wide range of ACN loadings to alter hardness; oil-resistant applications. Also available is terpolymer (see ABR) and tetrapolymer with styrene.
NR	Cis-poly(isoprene) natural rubber, essentially 100% cis, trans/vinyl <0.1%. Contains about 95% polyisoprene. Various grades available RSS, SMR, SIR, SLR, NIG with number identifying grade - 5, 10, 20. Also modified NR - PA, SP, OENR, ENR, DPNR. NR was the original general purpose (GP) rubber.
SBR	Random copolymer of styrene and butadiene. Styrene level varies from 10% to 80% but the general purpose level is 23.5%. Many types available and the exact type identified by a numeric code. General purpose rubber. Vast amounts used in tyres. Also available as ter/tetra polymer systems (see ABR & NBR).

‘T’ Group: Rubbers with Carbon, Oxygen and Sulphur in the Main Chain

OT	Polymer of bischloroalkylether (or formal), with sulphur. Most common one uses bis-2-chloroethylformal; CH2(OCH2CH2Cl)2 (with a little 1,2,3-trichloropropane for crosslinking) THIOKOL ST.
EOT	As above, but copolymerized with ethylene dichloride. All of these smell strongly of sulphur and are used for oil and solvent seals. The liquid polymers cold cure and are used as sealants in the building trade. Popular ones include Poly(ethylene disulphide) and Poly(butyl ether disulphide).

'U' Group: Polymer Chain Contains Carbon, Oxygen and Nitrogen

A wide range of materials used as oil-resistant materials, in oxidation-resisting applications and as lightweight shoe soling.

AU	Polyesterurethanes.
EU	Polyether urethanes.

Although not elastomers, certain other polymeric materials can exhibit “rubber-like” behaviour:

PVC	Poly(vinylchloride); hard brittle material (d = 1.4) often copolymerised with vinylidine chloride, vinyl acetate, styrene, ABR, ethylene vinyl acetate etc. for a wide range of applications. When plasticized, usually with esters such as phthalates, it becomes quite ‘rubbery’, used in conveyer belts, paints, varnishes, floor coverings, erasers (rubbers), flexible tubing, wellington boots and many cheap “rubber” goods. Thermoplastic.
PE	Polyethylene; a wide range of types available - HDPE (high density PE) and LDPE (low density PE). Numerous applications - medical implants to polythene bags, blended with elastomers such as EPDM to produce thermoplastic elastomers. Type distinguished by their melting points. - LDPE <110°C, HDPE up to 136°C. A reclaimed mixture shows a spread of melting points.
PP	Polypropylene; similar applications to PE but higher melting (165°C). Also used to make thermoplastic elastomers.
PS	Polystyrene; occasionally met as a reinforcing plastic within a continuous elastomeric phase (e.g.shoe soling) but can be considered to be present in some thermoplastic elastomers such as the block copolymers: 1.SIS styrene-isoprene-styrene 2.SBS styrene-butadiene-styrene

Chlorinated rubber; refers specifically to chlorinated natural rubber. Used for paints and adhesives. The theoretical level for (C5H8Cl2)n is 51% but commercial chlorinated rubber contains 65% Cl.

Rubber hydrochloride; again refers specifically to hydrochlorinated natural rubber - usually with about 90% of the double bonds hydrochlorinated (30% Cl). Plasticized material produced as film (e.g. PLIOFILM) was used for packaging.

M. G. Rubber; natural rubber to which methyl methacrylate has been grafted, commercial materials generally contain 30% or 49% w/w methacrylate.

GuttaPercha and Balata; Polyisoprene, with 100% of the units trans; pure material not unlike PVC in feel and, when plasticized, can have similar uses.

Chicle; a naturally occurring mixture of cis and trans polyisoprene (25:75), with resins, used in chewing-gum.

Guayule; natural cis-polyisoprene isolated from the shrub Parthenium argentatum by solvent extraction. Uses and properties as for NR, but smell reminiscent of gin. Efforts to develop commercial exploitation have not been particularly successful.