vi CONTENTS 3.5 Bonding and Molecular Structure 39 3.6 Stereoisomerism in Vinyl Polymers 40 3.7 Stereoisomerism in Diene Polymers 42 3.8 Summary 44 Problems 44 References 45 4 POLYMER MORPHOLOGY 46 4.1 Amorphous and Crystalline Polymers 47 4.2 The Effect of Polymer Structure,Temperature,and Solvent on Crystallinity 48 4.3 The Effect of Crystallinity on Polymer Density 49 4.4 The Effect of Crystallinity on Mechanical Properties 50 4.5 The Effect of Crystallinity on Optical Properties 51 4.6 Models for the Crystalline Structure of Polymers 53 4.7 Extended Chain Crystals 56 4.8 Liquid Crystal Polymers 57 Problems 59 References 60 5 CHARACTERIZATION OF MOLECULAR WEIGHT 61 5.1 Introduction 61 5.2 Average Molecular Weights 62 5.3 Determination of Average Molecular Weights 66 5.4 Molecular Weight Distributions 75 5.5 Gel Permeation (or Size-Exclusion)Chromatography (GPC,SEC) 79 5.6 Summary 85 Problems 86 References 89 6 THERMAL TRANSITIONS IN POLYMERS 91 6.1 Introduction 91 6.2 The Glass Transition 91 6.3 Molecular Motions in an Amorphous Polymer 92 6.4 Determination of Te 92 6.5 Factors that Influence T 95 6.6 The Effect of Copolymerization on T 97 6.7 The Thermodynamics of Melting 97 6.8 The Metastable Amorphous State 100 6.9 The Influence of Copolymerization on Thermal Properties 101 6.10 Effect of Additives on Thermal Properties 102