design and technology
POLYMERS
1. What are the two types of plastic?
Thermoplastics and Thermosetting plastics
2. What is the difference between the molecular structures of the two plastics?
The thermoplastics have long chains of molecules that are tangled together and have no fixed pattern but the thermosetting plastics have a long chain of molecule that are cross linked
3. What happens to the feel and properties of a plastic once a plasticiser is added during the manufacture of plastics?
The feel becomes rubbery making it more flexible and ideal for upholstery and clothing
4. What are the differences between the working characteristics of the two types of plastic?
Thermoplastics can be reheated and reshaped many times while thermosetting plastics cannot be reheated or reshaped
5. What is plastic memory?
The property of a plastic being able to go back to its original flat shape when reheated unless they have been damaged overheated or overstretched
6. All plastics have one key property. What is it?
A good electrical insulator
THERMOLPLASTIC
Polymer Properties uses Advantages Disadvantages
Acrylic Good impact strengths (tends not to shatter but to break into large pieces) lightweight good electrical insulator durable Ornamental fish tanks baths and bathroom furniture car indicator covers /reflectors Can be recycled excellent environment stability polishers and finishes well available in numerous colours Relatively soft scratches easily poor chemical resistance
Polyethene Tough
Resistance to chemicals
Soft and flexible
Good electrical insulator Carrier bags
Toys
Washing-up bowls
Bleach bottles
Buckets
Shampoo bottles Can be recycled but not easily excellent chemical resistance Although it can be recycled, most of the waste ends up in landfill sites
Polyvinyl
Chloride
(PVC) Good chemical resistance
Weather-resistance
Lightweight
Good electrical insulator
Stiff
Hard
Tough
1. What are the two types of plastic?
Thermoplastics and Thermosetting plastics
2. What is the difference between the molecular structures of the two plastics?
The thermoplastics have long chains of molecules that are tangled together and have no fixed pattern but the thermosetting plastics have a long chain of molecule that are cross linked
3. What happens to the feel and properties of a plastic once a plasticiser is added during the manufacture of plastics?
The feel becomes rubbery making it more flexible and ideal for upholstery and clothing
4. What are the differences between the working characteristics of the two types of plastic?
Thermoplastics can be reheated and reshaped many times while thermosetting plastics cannot be reheated or reshaped
5. What is plastic memory?
The property of a plastic being able to go back to its original flat shape when reheated unless they have been damaged overheated or overstretched
6. All plastics have one key property. What is it?
A good electrical insulator
THERMOLPLASTIC
Polymer Properties uses Advantages Disadvantages
Acrylic Good impact strengths (tends not to shatter but to break into large pieces) lightweight good electrical insulator durable Ornamental fish tanks baths and bathroom furniture car indicator covers /reflectors Can be recycled excellent environment stability polishers and finishes well available in numerous colours Relatively soft scratches easily poor chemical resistance
Polyethene Tough
Resistance to chemicals
Soft and flexible
Good electrical insulator Carrier bags
Toys
Washing-up bowls
Bleach bottles
Buckets
Shampoo bottles Can be recycled but not easily excellent chemical resistance Although it can be recycled, most of the waste ends up in landfill sites
Polyvinyl
Chloride
(PVC) Good chemical resistance
Weather-resistance
Lightweight
Good electrical insulator
Stiff
Hard
Tough