Plastics

There are two different types of plastics and they each have very different properties:

• Thermoplastics

- Soften when heated
- Can be reshaped

- They have chains of monomers with no links between them

• Thermosetting Plastics

- Can't be reshaped once cooled

- There are links between the monomer chains to stop movement between them.

SHAPING PLASTICS IS ALWAYS A HEAT PROCESS

Polymers
A general summary of polymers:

• Good electrical and thermal insulators
• Good strength to weight ratio
• Generally goo resistance to atmospheric and chemical erosion
• Low melting point
• Lightweight
• Available in a wide range of colours and transparency
• Two main categories, Thermoplastics and Thermosetting plastics

- Pigments are added to make the plastics colourful
- Thermosetting is cross linked monomers
- Thermoplastics are chains of monomers

Thermoplastics

• ABS- Acrylonitrile Butadiene Styrene
• CA- Cellulose Acetate
• Nylon- Polyamide
• PMMA- PolyMethylMethAcrylate- Acrylic
• PP- Polypropylene
• HIPS- High Impact Polystyrene
• PS- Polystyrene
• LDPE- Low Density Polyehtylene
• HDPE- High Density Polyehtylene
• uPVC- Polyvynil Chloride
• PVC- (Unplasticised flexible) Polyvynil Chloride
• PC- Poly Carbonate

Thermosets

• Epoxy resins- surface coatings and adhesives
• Melamine Formaldehyde- Tableware and decorative laminates
• Polyester Resins- Castings, Used in GRP
• Urea Formaldehyde- Electrical fittings and Adhesives