On a thermal trace, what marks the glass transition?

• A tall sharp peak
• A step in the baseline
• A sudden drop to zero

What happens to a polymer sample at the glass transition?

• Its segments start to wriggle and it turns rubbery
• Its chains snap into short pieces
• Its ordered regions all melt at once

Past the entanglement molar mass, chains loop together and the melt thickens fast.

Circle one:   True   False

One melt sits below the entanglement molar mass and one sits well above it. What differs?

• The longer melt is far thicker
• The longer melt flows more easily
• Both melts pour exactly alike

Two polymers share one backbone. One has bulky side groups. Which is stiffer at room temperature?

• The one without side groups
• Both feel exactly the same
• The one with bulky side groups

Why is the glass transition not a first-order transition?

• It happens too fast to measure
• It spreads over a range with no latent heat
• It only happens in ordered regions

A polar backbone grips neighboring chains, so it raises the transition temperature.

Circle one:   True   False

A student points at the melting peak and says the sample turned rubbery there. What is the mistake?

• The step marks melting, not the peak
• Crystallisation and melting are the same change
• Rubberiness starts at the earlier step