高分子物理（ 复旦大学） chapter5 Condensed States of Polymers 高分子的聚合状态.ppt

Chapter 5 Condensed States of Polymers 5.1 Polymer Melts and Glasses Glass Transition as a Relaxation Process 5.2 Polymer Crystallization 5.2.1 Chain Conformations in Crystals Why Helix ? Chain packing in crystal lattices Chain packing in crystal lattices 5.2.2 Basic Morphology of Polymer Crystals Lamellae Crystallized from Dilute Solution Orientations of polymer chains in lamellae Lamellae Crystallized from Melt Lamellae in a spherulite The mechanism of Maltese cross extinction pattern Theoretical analysis of Maltese cross extinction pattern Relations of POM and SALS (small angle light scattering) SALS patterns of spherulites 5.2.3 Polymer Crystallization Chain-Folded Lamellae of Polymers Process of Polymer CrystallizationTwo steps: Estimate the critical nucleus size 2. Linear Growth of Polymer Crystallization Overall Polymer Crystallization Rate Overall Crystallization Kinetics Avrami equation Kinetics models of overall crystallization 1. Free growth model Kinetics models of overall crystallization-Avrami 2.Impingement model Thermodynamics of Crystallization: 1. Melting point of Lamellar Crystals Thermodynamics of Crystallization: 1. Melting point of Lamellar Crystals Thermodynamics of Crystallization: 2. Melting point of Polymer mixture Effects of “Impurities” on Tm Effects of “Impurities” on Tm 3. Effects of Chain Structure on Tm 5.3 Oriented States of Polymers Definition Applications Fiber, BOPP, BOPET, BOPE, … Orientation function 5.4 Liquid Crystalline Polymers What are Liquid Crystals Nematic Phase (向列相) Smectic Phases (近晶相) Liquid Crystal Phase of Chiral Molecules Lyotropic liquid crystals: 1) surfactants or amphiphilic block copolymers Lyotropic liquid crystals:2) rigid-rod polymers POM Used in the Study of LC Phases POM Used in the Study of LC Phases Liquid Crystalline Polymers Thermodynamics of thermotropic liquid crystal transition Maier-Saupe Theory for LC Transition Phase Transition Temp. R~vt b. new nucleus produced - homogeneo