Molecular weight and molecular weight distribution are well known to affect the properties of polymeric materials. Even though for decades viscosity has been an integral part of product specifications used to characterize molecular weight of polymeric materials in industry, the need to define the molecular weight distribution of a product has attracted little attention. However, in recent years producers and users of polymeric materials have become ever more interested in value-added polymers with not only specific molecular weights but also optimal molecular weight distribution to offer unique performance advantages to products.
In fact, molecular weight distribution has become an important marketing feature for polymeric products in the 1990s. It is very common these days to see new grades of polymeric materials introduced to the marketplace that are specially designed to have either narrow or bimodal molecular weight distribution. In the case of a copolymer, the stress is on the uniformity in composition distribution throughout the entire molecular weight distribution. Therefore, the need to improve the analytical capability in R&D to characterize molecular weight distribution by size exclusion chromatography or gel permeation chromatography has become increasingly urgent in recent years.
Determination of molecular weight distribution of a polymer is very often not a simple task. Tins is one of the reasons it is still not commonly used as a final product specification. Many books have been published on size exclusion chromatography. However, there has still been a need for a book that stresses practical applications of size exclusion chromatography to the important polymeric materials in industry. Hopefully the valuable experiences of the authors in this book