Elastomers - Struct & Prop, Rubber Types SANS

Plastics and elastomers differ due to their properties

• resistivity

• dielectric strength

• acoustic insulation

• extensibility

Which of the following is not a characteristic of rubber?

• non-crystalline

• electrical conductivity

• chemical restistance

• low softening temperature

Which kind of polymer arrangement does the below diagram represent?

• unvulcanized

• vulcanized

• stretched vulcanized

• stretched unvulcanized

Which polymeric arrangement does the figure represent?

• unvulcanized

• vulcanized

• stretched vulcanized

• stretched unvulcanized

How does the crystallinity of an elastomer affect its strength?

• Increases with increase in crystallinity

• Increases with decrease in crystallinity

• Decreases with increase in crystallinity

• No effect

The loss of heat in elastomers due to friction is known as

• resilience

• hardness

• resistivity

• hysteresis

How is the hardness of an elastomer measured?

• Bloom

• Brinnell hardness test

• Rockwell hardness test

• Shore durometer

What is the thermal conductivity of rubber?

• 0.04 W/m ^oC

• 0.16 W/m ^oC

• .064 W/m ^oC

• 1.12 W/m ^oC

What is the trade name for natural polyisoprene?

• natural rubber

• neoprene

• silicone

• buna acrylonitrile

What is the percentage of elongation of styrene butadiene?

• 450-500%

• 400-600%

• 500-700%

• 800%