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DT > Theory - Polymers (Plastics) > Flashcards

Theory - Polymers (Plastics) Flashcards

1
Q

Plastics mainly come from………..

A

Crude Oil

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2
Q

What two groups are plastics divided into

A

Thermoforming Plastics

Thermosetting Plastics

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3
Q

What are Thermoforming plastics

A

Become soft and pliable when heated
Reheated as often as required
Can be shaped over and over again

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4
Q

What are Thermosetting plastics

A

Soft and pliable the first time they are heated but a chemical change takes place on cooling and they become rigid, non - flexible and cannot be reheated or changed

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5
Q

What is polymerisation

A

Occurs when MONOMERS join together to form a long chain called POLYMERS.
The word is deprived of “Poly” which means many.
And “Mer” which means parts

For example POLYSTYRENE are single monomers of STYRENE, going together to form a long chain

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6
Q

What are the characteristics of Thermoforming polymers

A

Soften when heated

Can be shaped when hot

The plastics will harden when cooled but can be reshaped if heated again

If heated and not shaped, tend to go back to their natural form

If overheated, the chemical structure will change

No links between misnomer chains, CAN BE RECYCLED

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7
Q

What are the characteristics of thermosetting polymers

A

Once heated and formed into a shape, they can’t be reformed

Brittle and hard

Prone to cracking if twisted and knocked

Heat resistant

Little movement between polymer chains, CANNOT BE RECYCLED

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8
Q

Give 9 thermoforming polymers

A 
Polyethylene Terephthalate (PET)
High - Density Polyethylene Terephthalate. (HDPE)
Polyvinyl Chloride (PVC)
Low - Density Polyethylene Terephthalate (LDPE)
Polypropylene (PP)
Rigid Polystyrene (PS)
Expand Polystyrene (PS) 
Acrylic (PMMA)
Acrylonitrile (ABS)
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9
Q

What are the characteristics of Polyethylene Terephthalate.

What is it used for

A

Moderate chemical resistance
Mainly used in transparent form

Drinks bottles, food containers

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10
Q

What are the characteristics of High - Density Polyethylene terephthalate.
What is it used for

A

Strong and stiff with excellent chemical resistance
Popular plastic that is easily coloured with an excellent finish.

Crates, Bowls, Buckets, Pipes

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11
Q

What are the characteristics of Polyvinyl Chloride.

What is it used for

A

Good chemical and weather resistance. Available in a number of forms with different properties.

Pipes, guttering, window frames, hoses, insulation cables

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12
Q

What are the characteristics of Low - Density Polyethylene Terephthalate.
What is it used for

A

Tough and flexible with good chemical resistance
A popular plastic that is easily coloured and has a smooth finish.

Detergent and shampoo bottles, toys, carrier bags, and transparent packaging

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13
Q

What are the characteristics of Polypropylene.

What is it used for

A

Lightweight
Food safe
Great chemical resistance
Good electrical insulator

Food containers, string, rope, medical equipment

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14
Q

What are the characteristics of Convectional Polystyrene.

What is it used for

A

Light
Hard
Toughed to increase impact strength

Popular for vacuum forming/food packaging

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15
Q

What are the characteristics of High Impact Polystyrene.

What is it used for

A

Good stiffness and impact resistance
Lightweight

Toys, refrigerator linings

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16
Q

What are the characteristics of Acrylic.

What is it used for

A

Tough
Can be brittle
Readily available
Food safe

Light Units, shop signs, car parts

17
Q

What are the characteristics of Polyamide, (NYLON)

What is it used for

A

Hard
Tough
Resistant to wear
Low friction

Bearings, gears, clothes

18
Q

What are the characteristics of Acrylonitrile Butadiene Styrene.
What is it used for

A

High impact strength
Lightweight
Durable
Scratch resistant

Kitchen products, mobile phone cases, toys and safety helmets

19
Q

Give 5 Thermosetting Plastics

A 
Polyester Resin
Epoxy Resin
Urea Formaldehyde
Phenol Formaladehyde
Melamine Formaldehyde
20
Q

What are the characteristics of Epoxy Resin.

What is it used for

A

Good chemical wear resistance
High strength when reinforced
Adhesive to many surfaces

Surface coatings, adhesives such as “Araldite”

21
Q

What are the characteristics of Melamine Formaldehyde.

What is it used for

A

Rigid
Good strength and hardness
Scratch resistant
Can be coloured

Laminates for work surfaces, tableware

22
Q

What are the characteristics of Phenol Formaldehyde.

What is it used for

A

Very good heat resistance
Very dark, hard
Quite brittle

Saucepan handles, cheap electrical fittings

23
Q

What are the characteristics of Polyester Resin.

What is it used for

A

Good heat and chemical resistance
Brittle but rigid

Embedding objects
Boat hulls
Car parts

24
Q

What are the characteristics of Urea Formaldehyde .

What is it used for

A 
Rigid
Brittle
Good strength
Heat resistant
Good electrical insulator

Adhesives
Electrical fittings, (e.g light switches and plugs)

25
Q

Give 5 added characteristics that can be given to plastics, and what they do

A

Plasticisers - make the plastic more flexible

Antistatics - reduce static

Fillers - such as glass strands, make the polymer stronger and improve impact resistance.

Pigments - change the colour

UV stabillers - withstand UV damage

26
Q

How is a plastic recycled, give the 5 steps

A 
Sorted
Shredded
Washed
Melted
Pelletised

DT (24 decks)

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