Lecture Notes: Solid-State Properties

A collection of vocabulary flashcards based on solid-state properties of polymers.

Celluloid

One of the first synthetic plastics produced by John Wesley Hyatt.

Amorphous Polymer

A polymer with long, randomly coiled chains that lack a defined crystalline structure.

Spherulite

A larger spherical superstructure made of many lamellae radiating outward with amorphous material among them.

Lamella

A thin plate-like crystalline region formed by folded polymer chains.

Glass Transition Temperature (Tg)

The temperature at which a polymer transitions from a brittle glassy state to a rubbery state.

Reptation

The model of chain motion in an entangled polymer melt, where a chain moves within a 'tube' formed by surrounding chains.

Critical Molecular Weight (Mc)

The minimum molecular weight needed for a polymer chain to form stable entanglements.

Melt

The state of a polymer heated above its melting temperature where it becomes soft and flowable.

Entropy (S)

A measure of the number of accessible configurations in a system; crucial in understanding thermal transitions.

First-Order Transition

A phase change (e.g., melting) where a first derivative of Gibbs free energy is discontinuous.

Second-Order Transition

A phase change (e.g., glass transition) where the first derivatives are continuous but the second derivatives are discontinuous.

Free Volume Theory

Theory explaining that glass transition occurs when the free volume in a polymer drops to a critical value.

Thermal Expansion Coefficient (α)

A measure of how much a material expands per unit length for a rise in temperature.

Kinetic Phenomenon

A behavior or process, such as Tg, that is influenced by the rate of changes in temperature and not purely thermodynamic properties.

Fox-Flory Equation

Empirical relationship that describes the dependence of Tg on molecular weight in polymers.

Tacticity

The stereoregularity of polymer chains, affecting crystallinity and packing efficiency.

Crystalline Region

Chain segments packed in an ordered, dense, and regular lattice formation.

Amorphous Region

Chains in a disordered state with random coil-like structures, which are less dense and more mobile.