Plastic: types

Question 1

2 categories

Answer 1

• thermoplastic
• thermosetting

All plastics are based on polymers and they are created by bonding molecules

Question 2

Thermosetting

Answer 2

• once it’s set, can’t be reheated to soften or shape or mould
• this is because molecules are cross linked
• bond between the molecules are very strong

Question 3

Example + uses of thermosetting

Answer 3

1. Nylon -> string -> comb
2. Low density polyethylene (LDPE) -> thin -> plastic bags, soft water bottle
3. High density polyethylene (HDPE) -> thicker -> bottles (range of colors), pipes *not safe for food
4. Polyethylene terephthalate (PET) -> standard water bottles *safe for food
5. Polyvinyl chloride (PVC) -> constructions -> toys -> clothing -> medical
6. Acrylic (PMMA) -> usually 3mm
7. Polystyrene (PS) -> form of sheets, balls, powder -> cups/plates for party *not good for environment
8. Polypropylene (PP) -> medical use -> strong structure
9. Acrylonitrile butadiene styrene (ABS) -> 3D printers, bottle caps

Question 4

Thermoplastic

Answer 4

• can be reheated and shaped in many ways
• become moldable after

Question 5

Example + uses of thermoplastic

Answer 5

1. Polyester resin (include GPR aka fibre glass) -> flat roofs, pipes, tanks -> waterproof, UV stability
2. Melamine formaldehyde (MF) -> surface walls, cabinets *not microwavable
3. Urea formaldehyde (UF) -> colorless chemical -> dizziness, skin irritation, nausea -> might trigger asthma -> insulator -> suitable for plug socket, toilet seat
   -> high melting point
4. Phenol formaldehyde (PF) -> common refer to WBP (*water and boil proof) -> provides structural and moisture durability -> brittle -> use with plywood
5. Epoxy resin