Polymers Flashcards
1
Q
Give the features of thermo-setting
A
Cross links - very strong
High melting point
Cant be remolded easy
Hard and rigid
2
Q
Give examples of where thermo-setting is used
A
rulers, yoghurt pots.
3
Q
State the features of thermo-softening
A
Weak forces of attraction
Low melting point
Remouldable
Soft and flexible
4
Q
Give an example where thermo-softening is used
A
Plastic bags
5
Q
What are the reaction conditons of Low Density Polyethene (LDPE)
A
Temp- 200 degrees
Pressure - 2000atm
Catalyst - trace of oxygen
6
Q
What are the reaction conditons of High Density Polyethene (HDPE)
A
Temp - 60 degrees
Pressure - 2atm
Catalysyt - Ziegler-Natta