7. Phase Transition Quiz

What is the temperature at which the transition occurs between the glassy and rubbery states of a polymer?

• Tg

• Tn

• Tm

• Tl

Which polymer is in viscous liquid phase at room temperature?l

• Poly(vinyl chloride) (PVC)

• Polydimethylsiloxane

• Polypropylene (atactic)

• Poly(vinyl acetate) (PVAc)

What is the main reason for polyethylene having a low Tg value?

• Presence of side groups

• High flexibility and absence of side groups

• Chain length

• Cross-linking

Which technique is used to study the transitions in polymers conveniently?

• FTIR

• Dilatometry

• HPLC

• Proximate

What is the term used to describe the time required for a protein to respond to a change in temperature or pressure?

• Transition

• Relaxation

• Dispersion

• Denaturation

Which factor DID NOT affects the gelatinization process of starch?

• Density

• pH

• Fat and Protein

• Sugar

Which one is NOT in the categories of the molecular motions in an amorphous polymer?

• Translational motion of entire molecules

• Cooperative wriggling & jumping of segments of molecules

• Vibration of bonds about equilibrium positions

• Motions of a few atoms along the main chain

Which theory defines Tg as the temperature at which the relaxation time for the segmental motions in the main polymer chain is of the same order of magnitude as the time scale of the experiment?

• Starch Gelatinization

• Free-Volume Theory

• Kinetic Theory

• Thermodynamic Theory

These are some structural factors that can affect Tg, EXCEPT

• Polarity

• Copolymerization

• Steric hindrance

• Diffusivity

Which source of starch has a gelatinization temperature range of 68-78 °C?

• Wheat

• Barley

• Potato

• Rice