ABSTRACT
In the early years of the rubber industry, natural rubber was the only material used for final products, and there was no need to know precisely the molecular characteristics such as average molecular weights and molecular weight distribution. However, since the introduction of various kinds of synthetic rubbers to the rubber industry, efforts have been devoted to understanding the correlations between their molecular weight characteristics and physical properties and processability. Apart from this technological aspect, considering the reaction of the chemical modification of current rubbers or the synthesis of new rubbers, elucidation of the molecular characteristics is the first necessary step for development. Until the introduction of gel permeation chromatography (GPC) to the method of polymer characterization in 1964 by Moore (1), a tedious molecular weight fractionation method or ultracentrifugal analysis was employed for these measurements. However, since then, GPC has been recognized as an invaluable zv168 method for the study of the molecular characterization of rubbers. At present, the term “size exclusion chromatography” (SEC) is more frequently used than GPC, and this is becoming much more refined in both hardware and software, as described elsewhere.
