The working properties, common uses and environmental impact of the following: 

– thermoplastics ○ acrylic (PMMA) ○ nylon ○ polyvinyl chloride (PVC) ○ polystyrene (PS) ○ polypropylene (PP) ○ high and low density polyethylene (HDPE) (LDPE) ○ high impact polystyrene (HIPS) ○ polycarbonate (PC) ○ acrylonitrile butadiene styrene (ABS) ○ polyethylene terephthalate (PET) 

– thermosetting plastics ○ polyester resin ○ melamine formaldehyde (MF) ○ urea formaldehyde (UF) ○ epoxy resin – elastomers ○ neoprene ○ silicone ○ thermoplastic elastomer (TPE).

Polymers are made up of long chain molecules containing carbon, hydrogen and oxygen atoms, along with other chemicals such as chlorine and fluorine.

Polymers occur naturally in nature and can be derived from plant and animal sources.

They include:

• Casein (derived from milk) which is still used to make buttons, 

• Horn, 

• Resin (from trees) 

• Cellulose from plants - In the case of Cellulose it is mixed with acetic acid to make Cellulose acetate which is still used today for OHP slides.

These could be classed as natural polymers as they possess a similar molecular structure to those polymers commercially used today.

Synthetic polymers are gained through a process of thermal cracking. As they are derived from fossil fuels (particularly oil) they are carbon based and account for the majority of plastics used today.

In order for it to be useful to us, crude oil is broken down in oil refineries into its component parts, known as fractions, and these can then be used for many different purposes.

Polymers have some unique properties which make them particularly useful for modern day applications.

• They are good electrical and thermal insulators

• They have a good strength to weight ratio. This does not mean they are strong in the same way as steel but that they have good strength compared to their weight.

• They generally have good atmospheric and chemical resistance.

• They have fairly low melting temperatures (Thermoplastics only)

• They are lightweight

• They can be self coloured, opaque or transparent and are self finishing.

• They are quite hygienic and are water resistant.

• They can be enhanced with the addition of fillers, plasticisers and stabilisers to make them more flame retardant or anti-static etc.

Thermoplastic Elastomers (TPE’s) can be processed using conventional moulding equipment i.e. injection moulding and have the advantage of quicker production times compared to natural or synthetic rubbers.

Another advantage is that all waste and scrap material can be recycled.

TPE’s are commonly used for wire and cable coatings, for seals and hoses in the automotive industry as well as over mouldings of grips onto power tools casings, toothbrushes, pens and utensils etc...