Experiment 20 - End group analysis

Abstract

The high molecular weight of a polymer is one of the most immediate consequences of the chain structures of these molecules. The ends of polymer chains sometimes consist of groups different from the monomer units that make up the body of the polymer molecule. The analysis of end groups is primarily useful for the determination of molecular weights and for studying the kinetics of polymerization and depolymerization. End group analysis can also be applied to studies of polymer inhibition. End group analysis is an important method for polymer characterization. A wide range of chemical and physical techniques are used for the determination of functional groups as well as end groups. This chapter focuses on molecular weight determination method based on end group analysis using titration. Estimation of the total end group content by either chemical or physical methods and of the number average molecular weight, by a method such as osmometry permits the calculation of the average number of end groups per molecule, which is a measurement of the degree of branching.