Mediaspace scheduled maintenance: Aug 25, 2026 07:00 - 12:00 AM. During this time, videos will be temporarily unavailable. Check status updates.

Lecture

Glass Transition: Theoretical Insights

In course

MSE-431: Physical chemistry of polymeric materials

The student has a basic understanding of the physical and physicochemical principles which result from the chainlike structure of synthetic macromolecules. The student can predict major characteristics of a polymer from its chemical structure and molecular ...

Description

This lecture delves into the concept of glass transition, explaining the calculation of heat capacity, crystallization, and melting processes using Differential Scanning Calorimetry (DSC). It covers the Newton's law of Viscosity, Elasticity, and the Williams-Landel-Ferry (WLF) Equation. The discussion extends to the Poisson's ratio, viscoelastic behavior, and the effect of molecular weight on the glass transition temperature. Various glass transition theories are explored, including the Free-Volume Theory, Kinetic Theory, and Thermodynamic Theory. The lecture also examines the impact of chemical structure on the glass transition temperature, the behavior of copolymers and mixtures, and the transitions observed by Dynamic Mechanical Analysis (DMA).

Official source

Ontological neighbourhood

Physics

Thermodynamics: Statistical mechanics

Related concepts (32)

Dynamic mechanical analysis

Dynamic mechanical analysis (abbreviated DMA) is a technique used to study and characterize materials. It is most useful for studying the viscoelastic behavior of polymers. A sinusoidal stress is applied and the strain in the material is measured, allowing one to determine the complex modulus. The temperature of the sample or the frequency of the stress are often varied, leading to variations in the complex modulus; this approach can be used to locate the glass transition temperature of the material, as well as to identify transitions corresponding to other molecular motions.

Phase transition

In chemistry, thermodynamics, and other related fields, a phase transition (or phase change) is the physical process of transition between one state of a medium and another. Commonly the term is used to refer to changes among the basic states of matter: solid, liquid, and gas, and in rare cases, plasma. A phase of a thermodynamic system and the states of matter have uniform physical properties. During a phase transition of a given medium, certain properties of the medium change as a result of the change of external conditions, such as temperature or pressure.

Thermal analysis

Thermal analysis is a branch of materials science where the properties of materials are studied as they change with temperature.

Kinetic theory of gases

The kinetic theory of gases is a simple, historically significant classical model of the thermodynamic behavior of gases, with which many principal concepts of thermodynamics were established. The model describes a gas as a large number of identical submicroscopic particles (atoms or molecules), all of which are in constant, rapid, random motion. Their size is assumed to be much smaller than the average distance between the particles. The particles undergo random elastic collisions between themselves and with the enclosing walls of the container.

Thermodynamic system

A thermodynamic system is a body of matter and/or radiation, considered as separate from its surroundings, and studied using the laws of thermodynamics. Thermodynamic systems may be isolated, closed, or open. An isolated system exchanges no matter or energy with its surroundings, whereas a closed system does not exchange matter but may exchange heat and experience and exert forces. An open system can interact with its surroundings by exchanging both matter and energy.

Related lectures (36)

Glass Transition: Polymer Properties

Explores glass and melting transitions in polymers, including characterization methods and specific polymer properties.

Elasticity: Constitutive Modelling in Geomechanics

Explores constitutive equations in geomechanics, stress-strain behavior, and practical applications in engineering.

Glass Transition: Theory and Applications

Explores the glass transition of polymeric materials, covering its definition, theory, and practical implications.

Elasticity and Deformation

Covers stress, strain, modulus of elasticity, and material behavior under different loads.

Phase Equilibria: Understanding Vapor-Liquid Separation

Provides an overview of vapor-liquid phase diagrams and their role in separation processes, focusing on phase equilibria and the Gibbs phase rule.