CHEM 332 Lecture Notes - Lecture 4: Stochastic Process, Glass Transition, Intermolecular Force
3 Oct 2016
School
Department
Course
Professor
Document Summary
Ethylene is when there are 2 ch2 groups within a polymer. Terephthalate is a benzene group with carboxylic groups. Can control the property of this polymer. If it is a rigid chain, there will not be much entanglement and will probably remain aligned in the solid state. Adding bulky/dense structure will interfere with the material, making it more loose", and thus is a plasticizer. Preventing the polymer chains from coming together reduced the number of intermolecular forces that keep the material together. Van der waals forces between molecules with induced dipoles (no obvious charge: induced dipoles- electron density on the surface changes due to a spontaneous imbalance of charges (temp charge that causes polarization) Plasticizers weaken these wan der waal forces, decreasing the stabilizing energy for a material, decreasing the tg, increasing mobility. A rough general rule is that dense materials are more stable o. Heat" computationally, and observe the change in slope this is the region for the tg.
