PHT121 Polymers

What is the glass transition temperature (Tg) of a polymer?

• The glass transition temperature (Tg) of a polymer is the temperature at which the polymer transitions from a hard, glassy state to a soft, rubbery state.

• The glass transition temperature (Tg) of a polymer is the temperature at which the polymer transitions from a crystalline state to an amorphous state.

• The glass transition temperature (Tg) of a polymer is the temperature at which the polymer transitions from a soft, rubbery state to a hard, glassy state.

• The glass transition temperature (Tg) of a polymer is the temperature at which the polymer transitions from a liquid state to a solid state.

How does the viscosity of a polymer change with temperature?

• Becomes solid

• Remains constant

• Increases

• Decreases

Explain the effect of temperature on the behavior of polymers.

• Temperature affects the mobility and flexibility of polymer chains.

• Temperature causes polymers to become more rigid and less flexible.

• Polymers become stronger at higher temperatures.

• Temperature has no effect on the behavior of polymers.

Discuss the relationship between molecular weight and viscosity in polymers.

• Viscosity decreases with molecular weight in polymers.

• Viscosity increases with molecular weight in polymers.

• There is no relationship between molecular weight and viscosity in polymers.

• Molecular weight and viscosity in polymers are inversely proportional.

Explain the concept of free volume in polymers and its relation to viscosity.

• Free volume in polymers refers to the color of the polymer. It is related to viscosity as darker polymers have higher viscosity.

• Free volume in polymers refers to the weight of the polymer. It is related to viscosity as heavier polymers have lower viscosity.

• Free volume in polymers refers to the temperature of the polymer. It is related to viscosity as higher temperature results in higher viscosity.

• Free volume in polymers refers to the space between polymer chains. It is related to viscosity as more free volume allows for easier movement of polymer chains, resulting in lower viscosity.

How does the chemical structure of a polymer affect its Tg?

• The mobility of its polymer chains

• The color of the polymer

• The electrical conductivity of the polymer

• The size of the polymer

Discuss the role of polymer chain entanglement in determining its viscosity.

• Polymer chain entanglement decreases the resistance to flow, leading to lower viscosity.

• Polymer chain entanglement only affects the color of the polymer, not its viscosity.

• Polymer chain entanglement increases the resistance to flow, leading to higher viscosity.

• Polymer chain entanglement has no effect on viscosity.