This is a relatively basic guide to plastic selection to help someone with minimal experience. There is tremendous variety in the field of thermoplastics. Firstly, there are a number of families of thermoplastics with familiar names such as polypropylene and nylon. Then within each of these, there are further categories and grades of the plastic. The situation is further complicated by blends between different families that can provide enhanced properties. Mechanical properties can also be easily modified through the use of fillers. Talc and fibreglass are both common additives.

It must be remembered that this is still not a mature field. The first Nylons were commercialized less than 70 years ago and new varieties of plastics

Relative cost 1.0

PP is easy to mould and colour. Natural resin is not clear (milky) even if some grades (PP random) shows acceptable transparency with thin walls (i.e. Tupperware food container). Mechanical properties are better than PE but still not very high compared with technical polymers such as PA or POM. Suitable for food contact. Suitable for outdoor use products.Can be used for injection moulding, extrusion, blow moulding, rotational moulding

Typical Products - plastic bottles, boxes, containers,caps, liquid tanks,plastic chairs, car bumpers, toys, gadgets.

Tradenames - Novolen (BASF), Verton (LNP), Clysar (Dupont) & many others

Relative cost - 1.2

PE is easy to mould and colour. Natural resin is milky rather than clear. Good impact resistance but low rigidity and mechanical properties, low surface hardness (scratches easily, could be very flexible so suitable for living hinges. Suitable for food contact. Widely used in the packaging industry for disposable items. Suitable for products used outdoors. Can be used for injection moulding, extrusion, blow moulding, rotational moulding.

Typical Products - plastic bottles, boxes, containers,pipes, caps, gaskets, toys, gadgets.

Tradnames - Dowlex (Dow), Paxon (Exxon) & many others

Relative cost - 1.5

PS is easy to mould and colour. Natural resin is clear, quite hard and brittle. Impact resistant grades are added with elastomer to improve mechanical properties but only solid colors are possible. Suitable for food contact. Can be used for injection moulding, extrusion, thermoforming, vacuumforming. Easy to paint, weld and glue.

Typical Products - Internal drawers and doors for fridges, internal walls for fridges, toys, gadgets.

Tradenames - Noryl (GE), Styrofoam (Dow) & many others

Relative cost - 1.8

ABS is easy to mold and color. Natural resin is normally not clear even if there are some clear grades (more expensive tha regular grades). Good mechanical properties, good aesthetical properties (surfaces can be very bright and shiny). Good dimensional stability. Can be used for injection molding, extrusion, thermoforming, vacuumforming.. Easy to paint, weld and glue.

Typical Products - Printers housing, monitor housings, toys, pieces of furniture.

Tradenames - Cycolac (GE), Lustran (Monsanto)

Relative Cost - 2.4 - 3.8

PMMA is easy to color and need some expertise to mold it properly. Natural resin is clear with excellent optical properties. Natural resin is quite hard and scratch resistant. Modified grades have good impact resistance but reduced hardness. Good aesthetical properties (surfaces can be very bright and shiny). It is used for injection molding, extrusion, thermoforming, casting.

Typical Products - Spectacle lenses, car's rear light shells, electronic device's windows,

Tradenames - Perspex (ICI), Plexiglass (Altuglas)

Relative Cost - 3.0 - 3.8

PC is easy to color but need some expertice to mold it properly. Natural resin is clear with good optical properties. Natural resin is not as hard as PMMA. PC has excellent impact resistance. Good aesthetical properties (surfaces can be very bright and shiny). It is used for injection molding, extrusion, thermoforming.

Typical Products - Safety helmets, plafoniere per lampade , phone housings, fari anteriori auto, CD

Tradenames - Caliber (Dow), Lexan (GE)

Relative Cost - 2.4 - 3.0

Nylon is a "technical polymer", it has very good mechanical properties it is easy to color but need some expertice to mold it properly. Natural resin is not clear. After molding Polyammide resins needs to absorb moisture (up to 10 %of their weight) to reach the best mechanical properties. It is used mainly for injection molding.

Typical Products - Mechanical components (gears, clips, heavy duty parts)

Tradenames - Zytel (Dupont), Capron (BASF) & many others

Relative Cost - 2.4 - 3.8

PVC comes in 2 varieties: flexible and rigid. The rigid variety is used primarily for plastic tubing and fittings because of its low cost and high resistance to solvents, etc. For this reason it is also extensively used in the medical field. It is easy to colour but requires a bit of experience to mould. It can be injection moulded, extruded, vacuum formed.

Flexible PVC has a plasticizer added that makes it soft. It is the outgassing of this chemical that gives new car interiors their characteristic smell.

Typical Products - water and electrical piping, inflatable boats and beach toys

Tradenames - Alpha (AlphaGary), Geon (PolyOne)

Relative Cost - 3.0 - 3.8

PET is used mostly to make synthetic fibres although most consumers will be more familiar with its use for drink bottles. PET is naturally colourless and odourless. It is impact resistant and can be used as a barrier for chemicals.

Typical Products - drink bottles, packaging, synthetic fibres

Tradenames - Mylar (film) - Dacron, Terylene fibres

Relative Cost - 2.4 - 3.0

POM is a "technical polymer", it has very good mechanical properties, it is easy to color but need some expertice to mold it properly. Natural resin is not clear. POM has quite low friction factor and good elastic memory. It is used mainly for injection molding.

Typical Products - gears, bushings, ski boots, ski bindings, impellers

Tradenames - Celcon (Hoechst), Delrin (Dupont), Ultraform (BASF)