Thermoplastic Polymers (Thermoplastics) (Leaving Cert Engineering): Flashcards
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Key property of thermoplastics
Key property of thermoplastics
Flexible when heated, rigid when cooled
3 examples of thermoplastics
3 examples of thermoplastics
Acrylic (Perspex), polythene, polypropylene
How thermoplastics are made
How thermoplastics are made
Addition polymerisation
Mer definition
Mer definition
Basic unit molecule used in polymerisation
What breaks double bonds in polymerisation
What breaks double bonds in polymerisation
Free radical (catalyst)
Thermoplastic structure type
Thermoplastic structure type
Amorphous (random, disorganised)
Primary bonding in thermoplastics
Primary bonding in thermoplastics
Covalent (very strong)
Secondary bonding in thermoplastics
Secondary bonding in thermoplastics
Van Der Wall's Forces (weak)
Why thermoplastics soften when heated
Why thermoplastics soften when heated
Van Der Wall's Forces break down
Co-polymers purpose
Co-polymers purpose
Mix chains to improve properties (harder/softer/rigid/flexible)
Effect of branching
Effect of branching
Creates firmer, more rigid material
Effect of crystalline regions
Effect of crystalline regions
More tensile strength along aligned chains